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Sun P, Shan R, Wang S, Chang H. Finite-time compensation control with dead-zone estimation for a rehabilitative walker considering internal disturbance forces. ISA TRANSACTIONS 2024; 152:256-268. [PMID: 39013690 DOI: 10.1016/j.isatra.2024.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 07/03/2024] [Accepted: 07/03/2024] [Indexed: 07/18/2024]
Abstract
This study discusses a finite-time compensation tracking control method for a rehabilitative training walker. The dynamic model with input dead zone was constructed to describe the walker, and a finite-time disturbance forces observation method was proposed based on the impact mechanism on tracking performance. This approach is novel in that the disturbance forces were observed in reverse through their effects on tracking performance, thus successfully obtaining the disturbance forces of the walker. To ensure the practical finite-time stability of the system, the nonlinear finite-time compensation tracking controller with stochastic configuration networks (SCN) dead-zone estimation was built for the rehabilitative walker. Simulation results and comparative analyses confirmed that the proposed compensation control method effectively restrains dead zone and internal disturbance forces.
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Affiliation(s)
- Ping Sun
- School of Artificial Intelligence, Shenyang University of Technology, 110870, PR China.
| | - Rui Shan
- School of Artificial Intelligence, Shenyang University of Technology, 110870, PR China.
| | - Shuoyu Wang
- Department of Intelligent Mechanical Systems Engineering, Kochi University of Technology, 7828502, Japan.
| | - Hongbin Chang
- School of Artificial Intelligence, Shenyang University of Technology, 110870, PR China.
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2
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Bodo G, Tessari F, Buccelli S, De Guglielmo L, Capitta G, Laffranchi M, De Michieli L. Customized Series Elastic Actuator for a Safe and Compliant Human-Robot Interaction: Design and Characterization. IEEE Int Conf Rehabil Robot 2023; 2023:1-6. [PMID: 37941251 DOI: 10.1109/icorr58425.2023.10304680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
When it comes to robotic-mediated rehabilitation it is mandatory to design a system that guarantees a safe and compliant human-machine interaction. Dealing with rehabilitative upper limb exoskeletons, Series Elastic Actuators offer a potential solution for this purpose. This work proposes four different solutions for SEAs' spring design. After an analysis on the mechanical requirements, four different solutions are explored and presented. The performances of the proposed highly integrated SEAs are compared. An initial static characterization provided insights on the linearity and repeatability of each spring torque-angle performances. The dynamics of the springs and their frequency responses are then analysed to show how it is possible to exploit our system for human-robot interaction applications.
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3
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Al-Dahiree OS, Ghazilla RAR, Tokhi MO, Yap HJ, Gul M. Design and Characterization of a Low-Cost and Efficient Torsional Spring for ES-RSEA. SENSORS (BASEL, SWITZERLAND) 2023; 23:3705. [PMID: 37050767 PMCID: PMC10099043 DOI: 10.3390/s23073705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/23/2023] [Accepted: 03/31/2023] [Indexed: 06/19/2023]
Abstract
The design of torsional springs for series elastic actuators (SEAs) is challenging, especially when balancing good stiffness characteristics and efficient torque robustness. This study focuses on the design of a lightweight, low-cost, and compact torsional spring for use in the energy storage-rotary series elastic actuator (ES-RSEA) of a lumbar support exoskeleton. The exoskeleton is used as an assistive device to prevent lower back injuries. The torsion spring was designed following design for manufacturability (DFM) principles, focusing on minimal space and weight. The design process involved determining the potential topology and optimizing the selected topology parameters through the finite element method (FEM) to reduce equivalent stress. The prototype was made using a waterjet cutting process with a low-cost material (AISI-4140-alloy) and tested using a custom-made test rig. The results showed that the torsion spring had a linear torque-displacement relationship with 99% linearity, and the deviation between FEM simulation and experimental measurements was less than 2%. The torsion spring has a maximum torque capacity of 45.7 Nm and a 440 Nm/rad stiffness. The proposed torsion spring is a promising option for lumbar support exoskeletons and similar applications requiring low stiffness, low weight-to-torque ratio, and cost-effectiveness.
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Affiliation(s)
- Omar Sabah Al-Dahiree
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia; (O.S.A.-D.)
| | - Raja Ariffin Raja Ghazilla
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia; (O.S.A.-D.)
| | | | - Hwa Jen Yap
- Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia; (O.S.A.-D.)
| | - Mustabshirha Gul
- Department of Mechanical Engineering, Faculty of Engineering and Technology, Bahauddin Zakariya University, Multan 60000, Pakistan
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4
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Sun T, Yang J. Adaptive Interaction Control of Compliant Robots Using Impedance Learning. SENSORS (BASEL, SWITZERLAND) 2022; 22:9740. [PMID: 36560108 PMCID: PMC9784497 DOI: 10.3390/s22249740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
This paper presents an impedance learning-based adaptive control strategy for series elastic actuator (SEA)-driven compliant robots without the measurement of the robot-environment interaction force. The adaptive controller is designed based on the command filter-based adaptive backstepping approach, where a command filter is used to decrease computational complexity and avoid the requirement of high derivatives of the robot position. In the controller, environmental impedance profiles and robotic parameter uncertainties are estimated using adaptive learning laws. Through a Lyapunov-based theoretical analysis, the tracking error and estimation errors are proven to be semiglobally uniformly ultimately bounded. The control effectiveness is illustrated through simulations on a compliant robot arm.
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5
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Wang H, Zhang Q, Sun Z, Tang X, Chen IM. Continuous Terminal Sliding-Mode Control for FJR Subject to Matched/Mismatched Disturbances. IEEE TRANSACTIONS ON CYBERNETICS 2022; 52:10479-10489. [PMID: 33872168 DOI: 10.1109/tcyb.2021.3066593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A robust finite-time control (FTC) framework using continuous terminal sliding-mode control (SMC) and high-order sliding-mode observer (HOSMO) is discussed to realize the trajectory tracking of flexible-joint robots in this article. Control performances of the robots always suffer from unknown matched and mismatched time-varying disturbances. Traditional SMC exists with a chattering phenomenon and cannot cope with mismatched time-varying disturbances due to its inherent structure property. For this reason, two HOSMOs are devised to estimate the time-varying disturbances on the link and motor side, respectively. Then, by fusing the states and disturbance estimations into a novel terminal sliding-mode surface, a continuous robust FTC scheme is developed. The proposed control strategy can not only handle both matched and mismatched time-varying disturbances but also obtain a finite-time convergence performance. The rigorous finite-time stability analysis of the closed-loop system under the proposed control method is guaranteed. The results are illustrated to verify the effectiveness and robustness of the proposed design approach.
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6
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Development of a Series Elastic Tendon Actuator (SETA) Based on Gait Analysis for a Knee Assistive Exosuit. ACTUATORS 2022. [DOI: 10.3390/act11060166] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
An exosuit is a wearable robot that assists the muscular strength of a human that wears it by using multiple wires with similar functions to human muscles. This study focuses on the development of a series elastic tendon actuator (SETA) for the actuation of an exosuit. A gait analysis was performed for walking on stairs to deduce the design requirements of SETA, and the necessary performances were then determined based on these requirements. The SETA is designed to assign compliance to rigid wires using linear springs. The deformation in linear springs generated during tension was measured through an encoder to calculate the human robot interaction (HRI) force. By utilizing the HRI force as feedback of an admittance controller, the SETA was capable of providing wire tensions required by an exosuit. The performance of the SETA was verified through series elastic component (SEC) deformation and force control experiments. The SEC deformation increased from 0 to 3.86 mm when the wire tension increased from 0 to 100 N. This force controller demonstrated a slight vibration owing to the mechanical properties of the springs constituting the SEC during the step input; however, the value gradually converged to 100 N. The developed SETA was applied to an exosuit system for supporting knee strength of the elderly when walking on stairs.
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Mo L, Feng P, Shao Y, Shi D, Ju L, Zhang W, Ding X. Anti-Disturbance Sliding Mode Control of a Novel Variable Stiffness Actuator for the Rehabilitation of Neurologically Disabled Patients. Front Robot AI 2022; 9:864684. [PMID: 35585837 PMCID: PMC9108206 DOI: 10.3389/frobt.2022.864684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/18/2022] [Indexed: 11/13/2022] Open
Abstract
Lower limb exoskeletons are widely used for rehabilitation training of patients suffering from neurological disorders. To improve the human–robot interaction performance, series elastic actuators (SEAs) with low output impedance have been developed. However, the adaptability and control performance are limited by the constant spring stiffness used in current SEAs. In this study, a novel load-adaptive variable stiffness actuator (LaVSA) is used to design an ankle exoskeleton. To overcome the problems of the LaVSA with a larger mechanical gap and more complex dynamic model, a sliding mode controller based on a disturbance observer is proposed. During the interaction process, due to the passive joints at the load side of the ankle exoskeleton, the dynamic parameters on the load side of the ankle exoskeleton will change continuously. To avoid this problem, the designed controller treats it and the model error as a disturbance and observes it with the disturbance observer (DOB) in real time. The first-order derivative of the disturbance set is treated as a bounded value. Subsequently, the parameter adaptive law is used to find the upper bound of the observation error and make corresponding compensation in the control law. On these bases, a sliding mode controller based on a disturbance observer is designed, and Lyapunov stability analysis is given. Finally, simulation and experimental verification are performed. The wearing experiment shows that the resistance torque suffered by humans under human–robot interaction is lower than 120 Nmm, which confirms that the controller can realize zero-impedance control of the designed ankle exoskeleton.
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Affiliation(s)
- Lufan Mo
- School of Mechanical Engineering and Automation, Beihang University, Beijing, China
| | - Pengbo Feng
- Beihang Goer (WeiFang) Intelligent Robot Co., Ltd, Weifang, China
| | - Yixin Shao
- School of Mechanical Engineering and Automation, Beihang University, Beijing, China
| | - Di Shi
- School of Mechanical Engineering and Automation, Beihang University, Beijing, China
- *Correspondence: Di Shi,
| | - Linhang Ju
- School of Mechanical Engineering and Automation, Beihang University, Beijing, China
| | - Wuxiang Zhang
- School of Mechanical Engineering and Automation, Beihang University, Beijing, China
- Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China
| | - Xilun Ding
- School of Mechanical Engineering and Automation, Beihang University, Beijing, China
- Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China
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Wang Q, Liu D, G. Carmichael M, Aldini S, Lin CT. Computational Model of Robot Trust in Human Co-Worker for Physical Human-Robot Collaboration. IEEE Robot Autom Lett 2022. [DOI: 10.1109/lra.2022.3145957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Zhong B, Guo K, Yu H, Zhang M. Toward Gait Symmetry Enhancement via a Cable-Driven Exoskeleton Powered by Series Elastic Actuators. IEEE Robot Autom Lett 2022. [DOI: 10.1109/lra.2021.3130639] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Li G, Li Z, Kan Z. Assimilation Control of a Robotic Exoskeleton for Physical Human-Robot Interaction. IEEE Robot Autom Lett 2022. [DOI: 10.1109/lra.2022.3144537] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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11
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Abstract
Abstract
With diverse areas of applications, wearable robotic exoskeleton devices have gained attention in the past decade. These devices cover one or more human limbs/joints and have been presented for rehabilitation, strength augmentation and interaction with virtual reality. This research is focused towards design, modeling and control of a novel series elastic actuation (SEA) based index finger exoskeleton with a targeted torque rendering capability of 0.3 Nm and a force control bandwidth of 3 Hz. The proposed design preserves the natural range of motion of the finger by incorporating five passive and two actively actuated joints and provides active control of metacarpophalangeal and proximal interphalangeal joints. Forward and inverse kinematics for both position and velocity have been solved using closed loop vector analysis by including human finger as an integral part of the system. For accurate force control, a cascaded control structure has been presented. Force controlled trajectories have been proposed to guide the finger along preprogrammed virtual paths. Such trajectories serve to gently guide the finger towards the correct rehabilitation protocol, thus acting as an effective replacement of intervention by a human therapist. Extensive computer simulations have been performed before fabricating a prototype and performing experimental validation. Results show accurate modeling and control of the proposed design.
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Wang T, Zheng T, Zhao S, Sui D, Zhao J, Zhu Y. Design and Control of a Series-Parallel Elastic Actuator for a Weight-Bearing Exoskeleton Robot. SENSORS (BASEL, SWITZERLAND) 2022; 22:1055. [PMID: 35161799 PMCID: PMC8840669 DOI: 10.3390/s22031055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/22/2022] [Accepted: 01/25/2022] [Indexed: 12/04/2022]
Abstract
Weight-bearing exoskeletons are robots that need to carry loads and interact with humans frequently. Therefore, the actuators of these exoskeletons are supposed to be capable of outputting sufficient force with high compliance and little weight. A series-parallel elastic actuator (SPEA) is designed, in this work, to meet the demanding requirements of an exoskeleton robot called PALExo. A gas spring is installed in parallel with an electric cylinder to adjust the force output range of the actuator according to the needs of the exoskeleton. A series elastic module (SEM) is installed in series with the electric cylinder and gas spring to improve the compliance of the actuator, the stiffness of which is variable to adapt to the different stiffness requirements of the exoskeleton's legs in the standing phase and swinging phase. A force controller combining dynamic compensation and a cascade control with an inner velocity loop and a disturbance observer is designed for the SPEA. The performance of the force controller is verified by experiments and the results demonstrate that the controller has good adaptability to the stiffness of the SEM.
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Affiliation(s)
| | | | | | | | | | - Yanhe Zhu
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin 150001, China; (T.W.); (T.Z.); (S.Z.); (D.S.); (J.Z.)
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13
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A Review on the Rehabilitation Exoskeletons for the Lower Limbs of the Elderly and the Disabled. ELECTRONICS 2022. [DOI: 10.3390/electronics11030388] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Research on the lower limb exoskeleton for rehabilitation have developed rapidly to meet the need of the aging population. The rehabilitation exoskeleton system is a wearable man–machine integrated mechanical device. In recent years, the vigorous development of exoskeletal technology has brought new ideas to the rehabilitation and medical treatment of patients with motion dysfunction, which is expected to help such people complete their daily physiological activities or even reshape their motion function. The rehabilitation exoskeletons conduct assistance based on detecting intention, control algorithm, and high-performance actuators. In this paper, we review rehabilitation exoskeletons from the aspects of the overall design, driving unit, intention perception, compliant control, and efficiency validation. We discussed the complexity and coupling of the man–machine integration system, and we hope to provide a guideline when designing a rehabilitation exoskeleton system for the lower limbs of elderly and disabled patients.
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14
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Xu D, Li X, Wang Y. Bionic design of universal gripper for nursing robot with hybrid joints and variable Equivalent Link Length. JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING 2022; 44:600. [PMCID: PMC9702696 DOI: 10.1007/s40430-022-03905-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 11/07/2022] [Indexed: 10/15/2023]
Abstract
Currently, most rehabilitation/nursing robots attach the human body to the end of the robot by ‘binding’ solution, which makes the operation complicated and greatly limits their applications. Therefore, it is necessary to study a universal gripper that can directly grasp human limbs as the end-effector of the robot. Inspired by the human hand, this paper proposes a bionic under-actuated gripper that imitates the structure of human hand. The concept of Equivalent Link Length (ELL) is proposed to optimize the envelope effect. And the structure with hybrid rotational and translational joints is proposed to increase gripping stiffness and to avoid the harmful component in the grip force. Theoretical analyses and experiments on envelope effect, force distribution and load capacity show that the propose gripper can grasp cylindrical (limb-shaped) objects with wide applicable size range, and also has a high load capacity. Furthermore, the gripper has the characteristic of almost constant force transfer ratio, which reduces the number of sensors required by the system. These results show that the gripper has the potential to be used in the nursing robot system.
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Affiliation(s)
- Dingmin Xu
- Key Laboratory of High-efficiency and Clean Mechanical Manufacture of MOE, National Demonstration Center for Experimental Mechanical Engineering Education, School of Mechanical Engineering, Shandong University, 17923 Jingshi Road, Jinan, 250061 China
| | - Xueyong Li
- Key Laboratory of High-efficiency and Clean Mechanical Manufacture of MOE, National Demonstration Center for Experimental Mechanical Engineering Education, School of Mechanical Engineering, Shandong University, 17923 Jingshi Road, Jinan, 250061 China
| | - Yonghui Wang
- Rehabilitation Center, Qilu Hospital of Shandong University, Jinan, 250012 Shandong China
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15
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A Novel Intrinsic Force Sensing Method for Robot Manipulators During Human–Robot Interaction. IEEE T ROBOT 2021. [DOI: 10.1109/tro.2021.3072736] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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16
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Tuan HM, Sanfilippo F, Hao NV. Modelling and Control of a 2-DOF Robot Arm with Elastic Joints for Safe Human-Robot Interaction. Front Robot AI 2021; 8:679304. [PMID: 34490356 PMCID: PMC8416520 DOI: 10.3389/frobt.2021.679304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/02/2021] [Indexed: 11/30/2022] Open
Abstract
Collaborative robots (or cobots) are robots that can safely work together or interact with humans in a common space. They gradually become noticeable nowadays. Compliant actuators are very relevant for the design of cobots. This type of actuation scheme mitigates the damage caused by unexpected collision. Therefore, elastic joints are considered to outperform rigid joints when operating in a dynamic environment. However, most of the available elastic robots are relatively costly or difficult to construct. To give researchers a solution that is inexpensive, easily customisable, and fast to fabricate, a newly-designed low-cost, and open-source design of an elastic joint is presented in this work. Based on the newly design elastic joint, a highly-compliant multi-purpose 2-DOF robot arm for safe human-robot interaction is also introduced. The mechanical design of the robot and a position control algorithm are presented. The mechanical prototype is 3D-printed. The control algorithm is a two loops control scheme. In particular, the inner control loop is designed as a model reference adaptive controller (MRAC) to deal with uncertainties in the system parameters, while the outer control loop utilises a fuzzy proportional-integral controller to reduce the effect of external disturbances on the load. The control algorithm is first validated in simulation. Then the effectiveness of the controller is also proven by experiments on the mechanical prototype.
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Affiliation(s)
- Hua Minh Tuan
- Department of Control Engineering and Automation, Faculty of Electrical and Electronic Engineering, Ho Chi Minh City University of Technology (HCMUT), Ho Chi Minh City, Vietnam.,Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Filippo Sanfilippo
- Department of Engineering Sciences, University of Agder (UiA), Grimstad, Norway
| | - Nguyen Vinh Hao
- Department of Control Engineering and Automation, Faculty of Electrical and Electronic Engineering, Ho Chi Minh City University of Technology (HCMUT), Ho Chi Minh City, Vietnam.,Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam
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Hussain F, Goecke R, Mohammadian M. Exoskeleton robots for lower limb assistance: A review of materials, actuation, and manufacturing methods. Proc Inst Mech Eng H 2021; 235:1375-1385. [PMID: 34254562 DOI: 10.1177/09544119211032010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The field of robot-assisted physical rehabilitation and robotics technology for providing support to the elderly population is rapidly evolving. Lower limb robot aided rehabilitation and assistive technology have been a focus for the engineering community during the last three decades as several robotic lower limb exoskeletons have been proposed in the literature as well as some being commercially available. Numerous manufacturing techniques and materials have been developed for lower limb exoskeletons during the last two decades, resulting in the design of a variety of robot exoskeletons for gait assistance for elderly and disabled people. One of the most important aspects of developing exoskeletons is the selection of the most appropriate proper material. The material selection strongly influences the overall weight and performance of the exoskeleton robot. The most suitable fabrication method for material is also an important parameter for the development of lower limb robot exoskeletons. In addition to the materials and manufacturing methods, the actuation method plays a vital role in the development of these robot exoskeletons. Even though various materials, manufacturing methods and actuators are reported in the literature for these lower limb robot exoskeletons, there are still avenues of improvement in these three domains. In this review, we have examined various lower limb robotic exoskeletons, concentrating on the three main aspects of material, manufacturing, and actuation. We have focused on the advantages and drawbacks of various materials and manufacturing practices as well as actuation methods. A discussion on future directions of research is provided for the engineering community covering the material, manufacturing and actuation methods.
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Affiliation(s)
- Fahad Hussain
- Human-Centred Technology Research Centre, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Roland Goecke
- Human-Centred Technology Research Centre, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Masoud Mohammadian
- Human-Centred Technology Research Centre, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
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18
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Maqsood K, Luo J, Yang C, Ren Q, Li Y. Iterative learning-based path control for robot-assisted upper-limb rehabilitation. Neural Comput Appl 2021. [DOI: 10.1007/s00521-021-06037-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AbstractIn robot-assisted rehabilitation, the performance of robotic assistance is dependent on the human user’s dynamics, which are subject to uncertainties. In order to enhance the rehabilitation performance and in particular to provide a constant level of assistance, we separate the task space into two subspaces where a combined scheme of adaptive impedance control and trajectory learning is developed. Human movement speed can vary from person to person and it cannot be predefined for the robot. Therefore, in the direction of human movement, an iterative trajectory learning approach is developed to update the robot reference according to human movement and to achieve the desired interaction force between the robot and the human user. In the direction normal to the task trajectory, human’s unintentional force may deteriorate the trajectory tracking performance. Therefore, an impedance adaptation method is utilized to compensate for unknown human force and prevent the human user drifting away from the updated robot reference trajectory. The proposed scheme was tested in experiments that emulated three upper-limb rehabilitation modes: zero interaction force, assistive and resistive. Experimental results showed that the desired assistance level could be achieved, despite uncertain human dynamics.
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19
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Koh MH, Yen SC, Leung LY, Gans S, Sullivan K, Adibnia Y, Pavel M, Hasson CJ. Exploiting telerobotics for sensorimotor rehabilitation: a locomotor embodiment. J Neuroeng Rehabil 2021; 18:66. [PMID: 33882949 PMCID: PMC8059234 DOI: 10.1186/s12984-021-00856-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/18/2021] [Indexed: 12/01/2022] Open
Abstract
Background Manual treadmill training is used for rehabilitating locomotor impairments but can be physically demanding for trainers. This has been addressed by enlisting robots, but in doing so, the ability of trainers to use their experience and judgment to modulate locomotor assistance on the fly has been lost. This paper explores the feasibility of a telerobotics approach for locomotor training that allows patients to receive remote physical assistance from trainers. Methods In the approach, a trainer holds a small robotic manipulandum that shadows the motion of a large robotic arm magnetically attached to a locomoting patient's leg. When the trainer deflects the manipulandum, the robotic arm applies a proportional force to the patient. An initial evaluation of the telerobotic system’s transparency (ability to follow the leg during unassisted locomotion) was performed with two unimpaired participants. Transparency was quantified by the magnitude of unwanted robot interaction forces. In a small six-session feasibility study, six individuals who had prior strokes telerobotically interacted with two trainers (separately), who assisted in altering a targeted gait feature: an increase in the affected leg’s swing length. Results During unassisted walking, unwanted robot interaction forces averaged 3−4 N (swing–stance) for unimpaired individuals and 2−3 N for the patients who survived strokes. Transients averaging about 10 N were sometimes present at heel-strike/toe-off. For five of six patients, these forces increased with treadmill speed during stance (R2 = .99; p < 0.001) and increased with patient height during swing (R2 = .71; p = 0.073). During assisted walking, the trainers applied 3.0 ± 2.8 N (mean ± standard deviation across patients) and 14.1 ± 3.4 N of force anteriorly and upwards, respectively. The patients exhibited a 20 ± 21% increase in unassisted swing length between Days 1−6 (p = 0.058). Conclusions The results support the feasibility of locomotor assistance with a telerobotics approach. Simultaneous measurement of trainer manipulative actions, patient motor responses, and the forces associated with these interactions may prove useful for testing sensorimotor rehabilitation hypotheses. Further research with clinicians as operators and randomized controlled trials are needed before conclusions regarding efficacy can be made.
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Affiliation(s)
- Min Hyong Koh
- Department of Physical Therapy, Movement and Rehabilitation Sciences, Northeastern University, 360 Huntington Avenue, 301 Robinson Hall, Boston, MA, 02115-5005, USA
| | - Sheng-Che Yen
- Department of Physical Therapy, Movement and Rehabilitation Sciences, Northeastern University, 360 Huntington Avenue, 301 Robinson Hall, Boston, MA, 02115-5005, USA
| | - Lester Y Leung
- Division of Stroke and Cerebrovascular Diseases, Department of Neurology, Tufts Medical Center, Boston, USA
| | - Sarah Gans
- Division of Stroke and Cerebrovascular Diseases, Department of Neurology, Tufts Medical Center, Boston, USA
| | - Keri Sullivan
- Division of Stroke and Cerebrovascular Diseases, Department of Neurology, Tufts Medical Center, Boston, USA
| | - Yasaman Adibnia
- Division of Stroke and Cerebrovascular Diseases, Department of Neurology, Tufts Medical Center, Boston, USA
| | - Misha Pavel
- Khoury College of Computer Sciences, Northeastern University, Boston, USA
| | - Christopher J Hasson
- Department of Physical Therapy, Movement and Rehabilitation Sciences, Northeastern University, 360 Huntington Avenue, 301 Robinson Hall, Boston, MA, 02115-5005, USA. .,Departments of Bioengineering and Biology, Northeastern University, Boston, USA.
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20
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Abstract
AbstractThe design and control of a cable-driven rehabilitation robot, which can be configured easily for exercising different articulations such as elbows, shoulders, hips, knees and ankles without requiring any orthosis, are introduced. The passive, active-assisted and active-resisted exercises were designed and implemented using impedance control. The controller could switch between exercises according to the force feedback. The effectiveness of the proposed controller was demonstrated by experimental studies. The robot was tested first with a dummy extremity and then with a healthy subject mimicking various types of patients during the tests. Experimental results showed that satisfactory closed-loop performances were achieved.
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21
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Mou F, Wu D, Dong Y. Disturbance rejection sliding mode control for robots and learning design. INTEL SERV ROBOT 2021. [DOI: 10.1007/s11370-021-00360-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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22
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Bhardwaj S, Khan AA, Muzammil M. Lower limb rehabilitation robotics: The current understanding and technology. Work 2021; 69:775-793. [PMID: 34180443 DOI: 10.3233/wor-205012] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND With the increasing rate of ambulatory disabilities and rise in the elderly population, advance methods to deliver the rehabilitation and assistive services to patients have become important. Lower limb robotic therapeutic and assistive aids have been found to improve the rehabilitation outcome. OBJECTIVE The article aims to present the updated understanding in the field of lower limb rehabilitation robotics and identify future research avenues. METHODS Groups of keywords relating to assistive technology, rehabilitation robotics, and lower limb were combined and searched in EMBASE, IEEE Xplore Digital Library, Scopus, Web of Science and Google Scholar database. RESULTS Based on the literature collected from the databases we provide an overview of the understanding of robotics in rehabilitation and state of the art devices for lower limb rehabilitation. Technological advancements in rehabilitation robotic architecture (sensing, actuation and control) and biomechanical considerations in design have been discussed. Finally, a discussion on the major advances, research directions, and challenges is presented. CONCLUSIONS Although the use of robotics has shown a promising approach to rehabilitation and reducing the burden on caregivers, extensive and innovative research is still required in both cognitive and physical human-robot interaction to achieve treatment efficacy and efficiency.
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Affiliation(s)
- Siddharth Bhardwaj
- Department of Mechanical Engineering, Aligarh Muslim University, Aligarh, UP, India
| | - Abid Ali Khan
- Department of Mechanical Engineering, Aligarh Muslim University, Aligarh, UP, India
| | - Mohammad Muzammil
- Department of Mechanical Engineering, Aligarh Muslim University, Aligarh, UP, India
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23
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Abu-Dakka FJ, Saveriano M. Variable Impedance Control and Learning-A Review. Front Robot AI 2020; 7:590681. [PMID: 33501348 PMCID: PMC7805898 DOI: 10.3389/frobt.2020.590681] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 10/22/2020] [Indexed: 11/13/2022] Open
Abstract
Robots that physically interact with their surroundings, in order to accomplish some tasks or assist humans in their activities, require to exploit contact forces in a safe and proficient manner. Impedance control is considered as a prominent approach in robotics to avoid large impact forces while operating in unstructured environments. In such environments, the conditions under which the interaction occurs may significantly vary during the task execution. This demands robots to be endowed with online adaptation capabilities to cope with sudden and unexpected changes in the environment. In this context, variable impedance control arises as a powerful tool to modulate the robot's behavior in response to variations in its surroundings. In this survey, we present the state-of-the-art of approaches devoted to variable impedance control from control and learning perspectives (separately and jointly). Moreover, we propose a new taxonomy for mechanical impedance based on variability, learning, and control. The objective of this survey is to put together the concepts and efforts that have been done so far in this field, and to describe advantages and disadvantages of each approach. The survey concludes with open issues in the field and an envisioned framework that may potentially solve them.
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Affiliation(s)
- Fares J. Abu-Dakka
- Intelligent Robotics Group, Department of Electrical Engineering and Automation (EEA), Aalto University, Espoo, Finland
| | - Matteo Saveriano
- Intelligent and Interactive Systems, Department of Computer Science and Digital Science Center (DiSC), University of Innsbruck, Innsbruck, Austria
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24
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Hamza MF, Ghazilla RAR, Muhammad BB, Yap HJ. Balance and stability issues in lower extremity exoskeletons: A systematic review. Biocybern Biomed Eng 2020. [DOI: 10.1016/j.bbe.2020.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Compliant Manipulation Method for a Nursing Robot Based on Physical Structure of Human Limb. J INTELL ROBOT SYST 2020. [DOI: 10.1007/s10846-020-01221-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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26
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Xia J, Huang D, Li Y, Qin N. Iterative learning of human partner’s desired trajectory for proactive human–robot collaboration. INTERNATIONAL JOURNAL OF INTELLIGENT ROBOTICS AND APPLICATIONS 2020. [DOI: 10.1007/s41315-020-00132-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
AbstractA period-varying iterative learning control scheme is proposed for a robotic manipulator to learn a target trajectory that is planned by a human partner but unknown to the robot, which is a typical scenario in many applications. The proposed method updates the robot’s reference trajectory in an iterative manner to minimize the interaction force applied by the human. Although a repetitive human–robot collaboration task is considered, the task period is subject to uncertainty introduced by the human. To address this issue, a novel learning mechanism is proposed to achieve the control objective. Theoretical analysis is performed to prove the performance of the learning algorithm and robot controller. Selective simulations and experiments on a robotic arm are carried out to show the effectiveness of the proposed method in human–robot collaboration.
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27
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Huo W, Alouane MA, Amirat Y, Mohammed S. Force Control of SEA-Based Exoskeletons for Multimode Human–Robot Interactions. IEEE T ROBOT 2020. [DOI: 10.1109/tro.2019.2956341] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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28
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Sun T, Peng L, Cheng L, Hou ZG, Pan Y. Composite Learning Enhanced Robot Impedance Control. IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 2020; 31:1052-1059. [PMID: 31107667 DOI: 10.1109/tnnls.2019.2912212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The desired impedance dynamics can be achieved for a robot if and only if an impedance error converges to zero or a small neighborhood of zero. Although the convergence of impedance errors is important, it is seldom obtained in the existing impedance controllers due to robots modeling uncertainties and external disturbances. This brief proposes two composite learning impedance controllers (CLICs) for robots with parameter uncertainties based on whether a factorization assumption is satisfied or not. In the proposed control designs, the convergence of impedance errors, reflected by the convergence of parameter estimation errors and some auxiliary errors, is achieved by using composite learning laws under a relaxed excitation condition. The theoretical results are proven based on the Lyapunov theory. The effectiveness and advantages of the proposed CLICs are validated by simulations on a parallel robot in three cases.
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29
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Zhang Q, Sun D, Qian W, Xiao X, Guo Z. Modeling and Control of a Cable-Driven Rotary Series Elastic Actuator for an Upper Limb Rehabilitation Robot. Front Neurorobot 2020; 14:13. [PMID: 32161531 PMCID: PMC7052376 DOI: 10.3389/fnbot.2020.00013] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 02/06/2020] [Indexed: 11/13/2022] Open
Abstract
This paper focuses on the design, modeling, and control of a novel remote actuation, including a compact rotary series elastic actuator (SEA) and Bowden cable. This kind of remote actuation is used for an upper limb rehabilitation robot (ULRR) with four powered degrees of freedom (DOFs). The SEA mainly consists of a DC motor with planetary gearheads, inner/outer sleeves, and eight linearly translational springs. The key innovations include (1) an encoder for direct spring displacement measurement, which can be used to calculate the output torque of SEA equivalently, (2) the embedded springs can absorb the negative impact of backlash on SEA control performance, (3) and the Bowden cable enables long-distance actuation and reduces the bulky structure on the robotic joint. In modeling of this actuation, the SEA's stiffness coefficient, the dynamics of the SEA, and the force transmission of the Bowden cable are considered for computing the inputs on each powered joint of the robot. Then, both torque and impedance controllers consisting of proportional-derivative (PD) feedback, disturbance observer (DOB), and feedforward compensation terms are developed. Simulation and experimental results verify the performance of these controllers. The preliminary results show that this new kind of actuation can not only implement stable and friendly actuation over a long distance but also be customized to meet the requirements of other robotic system design.
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Affiliation(s)
- Qiang Zhang
- School of Power and Mechanical Engineering, Wuhan University, Wuhan, China.,UNC/NCSU Joint Department of Biomedical Engineering, NC State University, Raleigh, NC, United States
| | - Dingyang Sun
- School of Power and Mechanical Engineering, Wuhan University, Wuhan, China
| | - Wei Qian
- School of Power and Mechanical Engineering, Wuhan University, Wuhan, China
| | - Xiaohui Xiao
- School of Power and Mechanical Engineering, Wuhan University, Wuhan, China.,Wuhan University Shenzhen Research Institute, Shenzhen, China
| | - Zhao Guo
- School of Power and Mechanical Engineering, Wuhan University, Wuhan, China.,Wuhan University Shenzhen Research Institute, Shenzhen, China
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30
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Cremer S, Das SK, Wijayasinghe IB, Popa DO, Lewis FL. Model-Free Online Neuroadaptive Controller With Intent Estimation for Physical Human–Robot Interaction. IEEE T ROBOT 2020. [DOI: 10.1109/tro.2019.2946721] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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31
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Kim D, Koh K, Cho GR, Zhang LQ. A Robust Impedance Controller Design for Series Elastic Actuators using the Singular Perturbation Theory. IEEE/ASME TRANSACTIONS ON MECHATRONICS : A JOINT PUBLICATION OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY AND THE ASME DYNAMIC SYSTEMS AND CONTROL DIVISION 2020; 25:164-174. [PMID: 32431485 PMCID: PMC7236756 DOI: 10.1109/tmech.2019.2951417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Impedance control is capable of further flexibly adjusting the driving-point impedance of series elastic actuators (SEAs) in addition to impedance reduction by the elastic element. This enhances safety and compliance during interaction between humans and robots, in comparison with rigid robots under impedance control or SEAs under position control. In this study, we propose an impedance controller for SEA systems that is developed based on the singular perturbation (SP) theory and time-delay estimation (TDE) technique. The SP theory allows for alleviating the burden of the requirement for states to be measured. The TDE technique is effective in compensating for system dynamics and uncertainties involved in system behaviors with minute computation loads. Employing both a simulation study and experimental study, we demonstrate the efficacy of the proposed control created from the combination of the SP theory and TDE technique. The effect of the proposed impedance control on reducing the driving-point impedance of interacting SEAs is examined.
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Affiliation(s)
- Dongwon Kim
- Department of Physical Therapy and Rehabilitation Science, University of Maryland Baltimore, Baltimore, MD 21201 USA, and also with the Department of Bioengineering, University of Maryland College Park, College Park, MD 20742 USA
| | - Kyung Koh
- Department of Physical Therapy and Rehabilitation Science, University of Maryland Baltimore, Baltimore, MD 21201 USA
| | - Gun-Rae Cho
- Korea Institute of Robot and Convergence Website Directions, Pohang 37666 South Korea
| | - Li-Qun Zhang
- Department of Physical Therapy and Rehabilitation Science, and the Department of Orthopaedics, University of Maryland Baltimore, Baltimore, MD 21201 USA, and also with the Department of Bioengineering, University of Maryland College Park, College Park, MD 20742 USA
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32
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Human postural ankle torque control model during standing posture with a series elastic muscle-tendon actuator. SN APPLIED SCIENCES 2020. [DOI: 10.1007/s42452-020-1955-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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33
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Nalbach S, Banda RM, Croce S, Rizzello G, Naso D, Seelecke S. Modeling and Design Optimization of a Rotational Soft Robotic System Driven by Double Cone Dielectric Elastomer Actuators. Front Robot AI 2020; 6:150. [PMID: 33501165 PMCID: PMC7806115 DOI: 10.3389/frobt.2019.00150] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 12/16/2019] [Indexed: 11/13/2022] Open
Abstract
Dielectric elastomers (DEs) consist of highly compliant electrostatic transducers which can be operated as actuators, by converting an applied high voltage into motion, and as sensors, since capacitive changes can be related to displacement information. Due to large achievable deformation (on the order of 100%) and high flexibility, DEs appear as highly suitable for the design of soft robotic systems. An important requirement for robotic systems is the possibility of generating a multi degree-of-freedom (MDOF) actuation. By means of DE technology, a controllable motion along several directions can be made possible by combining different membrane actuators in protagonist-antagonist configurations, as well as by designing electrode patterns which allow independent activation of different sections of a single membrane. However, despite several concepts of DE soft robots have been presented in the recent literature, up to date there is still a lack of systematic studies targeted at optimizing the design of the system. To properly understand how different parameters influence the complex motion of DE soft robots, this paper presents an experimental study on how geometry scaling affects the performance of a specific MDOF actuator configuration. The system under investigation consists of two cone DE membranes rigidly connected along the outer diameter, and pre-compressed out-of-plane against each other via a rigid spacer. The electrodes of both membranes are partitioned in four sections that can be activated separately, thus allowing the desired MDOF actuation feature. Different prototypes are assembled and tested to study the influence of the inner radius as well as the length of the rigid spacer on the achievable motion range. For the first experimental study presented here, we focus our analysis on a single actuation variable, i.e., the rotation of the rigid spacer about a fixed axis. A physics-based model is then developed and validated based on the collected experimental measurements. A model-based investigation is subsequently performed, with the aim of studying the influence of the regarded parameters on the rotation angle. Finally, based on the results of the performed study, a model-based optimization of the prototype geometry is performed.
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Affiliation(s)
- Sophie Nalbach
- Center for Mechatronics and Automation Technologies (ZeMA) gGmbH, Saarbrücken, Germany
- Department of Systems Engineering, Saarland University, Saarbrücken, Germany
- Department of Material Science and Engineering, Saarland University, Saarbrücken, Germany
| | - Rukmini Manoz Banda
- Department of Systems Engineering, Saarland University, Saarbrücken, Germany
- Department of Material Science and Engineering, Saarland University, Saarbrücken, Germany
| | - Sipontina Croce
- Department of Electrical and Information Engineering, Polytechnic University of Bari, Bari, Italy
| | - Gianluca Rizzello
- Department of Systems Engineering, Saarland University, Saarbrücken, Germany
- Department of Material Science and Engineering, Saarland University, Saarbrücken, Germany
| | - David Naso
- Department of Electrical and Information Engineering, Polytechnic University of Bari, Bari, Italy
| | - Stefan Seelecke
- Center for Mechatronics and Automation Technologies (ZeMA) gGmbH, Saarbrücken, Germany
- Department of Systems Engineering, Saarland University, Saarbrücken, Germany
- Department of Material Science and Engineering, Saarland University, Saarbrücken, Germany
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34
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Jamwal PK, Hussain S, Ghayesh MH. Robotic orthoses for gait rehabilitation: An overview of mechanical design and control strategies. Proc Inst Mech Eng H 2020; 234:444-457. [PMID: 31916511 DOI: 10.1177/0954411919898293] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The application of robotic devices in providing physiotherapies to post-stroke patients and people suffering from incomplete spinal cord injuries is rapidly expanding. It is crucial to provide valid rehabilitation for people who are experiencing abnormality in their gait performance; therefore, design and development of newer robotic devices for the purpose of facilitating patients' recovery is being actively researched. In order to advance the traditional gait treatment among patients, exoskeletons and orthoses were introduced over the last two decades. This article presents a thorough review of existing robotic gait rehabilitation devices. The latest advancements in the mechanical design, types of control and actuation are also covered. The study comprehends discussions on robotic rehabilitation devices developed both for the training on treadmill and over-ground training. The assist-as-needed strategy for the gait training is particularly emphasized while reviewing various control strategies applied to these robotic devices. This study further reviews experimental investigations and clinical assessments of different control strategies and mechanism designs of robotic gait rehabilitation devices using experimental and clinical trials.
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Affiliation(s)
- Prashant K Jamwal
- Department of Electrical and Computer Engineering, Nazarbayev University, Astana, Kazakhstan
| | - Shahid Hussain
- Human-Centred Technology Research Centre, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Mergen H Ghayesh
- School of Mechanical Engineering, The University of Adelaide, Adelaide, SA, Australia
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35
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XU TIAN, FAN JIZHUANG, FANG QIANQIAN, ZHAO JIE, ZHU YANHE. ROBOTIC ARM COLLISION REACTION STRATEGIES FOR SAFE HUMAN–ROBOT INTERACTION WITHOUT TORQUE SENSORS. J MECH MED BIOL 2019. [DOI: 10.1142/s0219519419400347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Three kinds of collision reaction strategies for increasing safety during human and robot interactions without relying on torque sensors are proposed in this paper. In the proposed algorithms, motor torque is estimated by driver current. The generalized momentum observer is used for collision detection, which does not need joints acceleration information and calculates the inverse of the inertia matrix. Three different collision reaction strategies, going away, dragging by hands and mechanical impedance developed in this paper, aim to enhance safety to humans during physical interaction with robots. For verifying the efficiency of the proposed algorithms, experiments are tested between a 1-DOF manipulator system and a human being. At last, the experiments’ results show that the proposed collision reaction algorithms are effective.
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Affiliation(s)
- TIAN XU
- State Key Laboratory of Robotics and System, School of Mechatronics Engineering, Harbin Institute of Technology Harbin, Heilongjiang 150080, P. R. China
| | - JIZHUANG FAN
- State Key Laboratory of Robotics and System, School of Mechatronics Engineering, Harbin Institute of Technology Harbin, Heilongjiang 150080, P. R. China
| | - QIANQIAN FANG
- State Key Laboratory of Robotics and System, School of Mechatronics Engineering, Harbin Institute of Technology Harbin, Heilongjiang 150080, P. R. China
| | - JIE ZHAO
- State Key Laboratory of Robotics and System, School of Mechatronics Engineering, Harbin Institute of Technology Harbin, Heilongjiang 150080, P. R. China
| | - YANHE ZHU
- State Key Laboratory of Robotics and System, School of Mechatronics Engineering, Harbin Institute of Technology Harbin, Heilongjiang 150080, P. R. China
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36
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Ghidini S, Beschi M, Pedrocchi N. A Robust Linear Control Strategy to Enhance Damping of a Series Elastic Actuator on a Collaborative Robot. J INTELL ROBOT SYST 2019. [DOI: 10.1007/s10846-019-01071-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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37
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Mechanical and Control Design of an Industrial Exoskeleton for Advanced Human Empowering in Heavy Parts Manipulation Tasks. ROBOTICS 2019. [DOI: 10.3390/robotics8030065] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Exoskeleton robots are a rising technology in industrial contexts to assist humans in onerous applications. Mechanical and control design solutions are intensively investigated to achieve a high performance human-robot collaboration (e.g., transparency, ergonomics, safety, etc.). However, the most of the investigated solutions involve high-cost hardware, complex design solutions and standard actuation. Moreover, state-of-the-art empowering controllers do not allow for online assistance regulation and do not embed advanced safety rules. In the presented work, an industrial exoskeleton with high payload ratio for lifting and transportation of heavy parts is proposed. A low-cost mechanical design solution is described, exploiting compliant actuation at the shoulder joint to increase safety in human-robot cooperation. A hierarchic model-based controller with embedded safety rules is then proposed (including the modeling of the compliant actuator) to actively assist the human while executing the task. An inner optimal controller is proposed for trajectory tracking, while an outer safety-based fuzzy logic controller is proposed to online deform the task trajectory on the basis of the human’s intention of motion. A gain scheduler is also designed to calculate the inner optimal control gains on the basis of the performed trajectory. Simulations have been performed in order to validate the performance of the proposed device, showing promising results. The prototype is under realization.
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38
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Hamaya M, Matsubara T, Teramae T, Noda T, Morimoto J. Design of physical user–robot interactions for model identification of soft actuators on exoskeleton robots. Int J Rob Res 2019. [DOI: 10.1177/0278364919853618] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent breakthroughs in wearable robots, such as exoskeleton robots with soft actuators and soft exosuits, have enabled the use of safe and comfortable movement assistance. However, modeling and identification methods for soft actuators used in wearable robots have yet to be sufficiently explored. In this study, we propose a novel approach for obtaining accurate soft actuator models through the design of physical user–robot interactions for wearable robots, in which the user applies external forces to the robot. To obtain an accurate soft actuator model from the limited amount of data acquired through an interaction, we leverage an active learning framework based on Gaussian process regression. We conducted experiments using a two-degree-of-freedom upper-limb exoskeleton robot with four pneumatic artificial muscles (PAMs). Experimental results showed that physical interactions between the exoskeleton robot and the user were successfully designed to allow PAM models to be identified. Furthermore, we found that data acquired through an interaction could result in more accurate soft actuator models for the exoskeleton robots than data acquired without a physical interaction between the exoskeleton robot and the user.
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Affiliation(s)
- Masashi Hamaya
- The Department of Brain Robot Interface, ATR-CNS, Kyoto, Japan
- The Graduate School of Frontier Bioscience, Osaka University, Osaka, Japan
| | - Takamitsu Matsubara
- The Department of Brain Robot Interface, ATR-CNS, Kyoto, Japan
- The Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
| | - Tatsuya Teramae
- The Department of Brain Robot Interface, ATR-CNS, Kyoto, Japan
| | - Tomoyuki Noda
- The Department of Brain Robot Interface, ATR-CNS, Kyoto, Japan
| | - Jun Morimoto
- The Department of Brain Robot Interface, ATR-CNS, Kyoto, Japan
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39
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Sanchez-Villamañan MDC, Gonzalez-Vargas J, Torricelli D, Moreno JC, Pons JL. Compliant lower limb exoskeletons: a comprehensive review on mechanical design principles. J Neuroeng Rehabil 2019; 16:55. [PMID: 31072370 PMCID: PMC6506961 DOI: 10.1186/s12984-019-0517-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 03/26/2019] [Indexed: 12/04/2022] Open
Abstract
Exoskeleton technology has made significant advances during the last decade, resulting in a considerable variety of solutions for gait assistance and rehabilitation. The mechanical design of these devices is a crucial aspect that affects the efficiency and effectiveness of their interaction with the user. Recent developments have pointed towards compliant mechanisms and structures, due to their promising potential in terms of adaptability, safety, efficiency, and comfort. However, there still remain challenges to be solved before compliant lower limb exoskeletons can be deployed in real scenarios. In this review, we analysed 52 lower limb wearable exoskeletons, focusing on three main aspects of compliance: actuation, structure, and interface attachment components. We highlighted the drawbacks and advantages of the different solutions, and suggested a number of promising research lines. We also created and made available a set of data sheets that contain the technical characteristics of the reviewed devices, with the aim of providing researchers and end-users with an updated overview on the existing solutions.
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Affiliation(s)
| | - Jose Gonzalez-Vargas
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Avda Doctor Arce, 37, E-28002 Madrid, Spain
| | - Diego Torricelli
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Avda Doctor Arce, 37, E-28002 Madrid, Spain
| | - Juan C. Moreno
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Avda Doctor Arce, 37, E-28002 Madrid, Spain
| | - Jose L. Pons
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Avda Doctor Arce, 37, E-28002 Madrid, Spain
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40
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Senoo T, Murakami K, Ishikawa M. Deformation Control of a Manipulator Based on the Zener Model. JOURNAL OF ROBOTICS AND MECHATRONICS 2019. [DOI: 10.20965/jrm.2019.p0263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this study, passive dynamic control of a manipulator is designed and realized. According to the control strategy, the shift in the position and orientation of an end effector attributable to an external force is regarded as deformation of the robot. The Zener model, known as a standard linear solid model, is used to generate the deformable behavior, which describes the combination of plastic and elastic deformation. Based on the relation analysis between the Zener model and two other deformable models, two types of control methods are proposed in terms of the model’s expression. Physical simulations with a robotic arm are executed to validate the proposed control laws.
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41
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Di Lallo A, Catalano MG, Garabini M, Grioli G, Gabiccini M, Bicchi A. Dynamic Morphological Computation Through Damping Design of Soft Continuum Robots. Front Robot AI 2019; 6:23. [PMID: 33501039 PMCID: PMC7806024 DOI: 10.3389/frobt.2019.00023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 03/11/2019] [Indexed: 01/19/2023] Open
Abstract
Inspired by nature, soft robotics aims at enhancing robots capabilities through the use of soft materials. This article presents the study of soft continuum robots which can change their dynamic behavior thanks to a proper design of their damping properties. It enables an under-actuated dynamic strategy to control multi-chamber pneumatic systems using a reduced number of feeding lines. The present work starts from the conceptual investigation of a way to tune the damping properties of soft continuum robots, and leverages on the introduction of viscous fluid within the soft chamber wall to produce dissipative actions. Several solutions are analyzed in simulations and the most promising one is tested experimentally. The proposed approach employs a layer of granular material immersed in viscous silicone oil to increase the damping effect. After validation and experimental characterization, the method is employed to build soft continuum actuators with different deformation patterns, i.e., extending, contracting and bending. Experimental results show the dynamic behavior of the presented actuators. Finally, the work reports information on how the actuators are designed and builded, together with a discussion about possible applications and uses.
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Affiliation(s)
- Antonio Di Lallo
- Dipartimento di Ingegneria dell'Informazione, Centro di Ricerca E. Piaggio, Università di Pisa, Pisa, Italy.,Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Pisa, Italy
| | | | - Manolo Garabini
- Dipartimento di Ingegneria dell'Informazione, Centro di Ricerca E. Piaggio, Università di Pisa, Pisa, Italy
| | - Giorgio Grioli
- Fondazione Istituto Italiano di Tecnologia, Genoa, Italy
| | - Marco Gabiccini
- Dipartimento di Ingegneria dell'Informazione, Centro di Ricerca E. Piaggio, Università di Pisa, Pisa, Italy.,Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Pisa, Italy
| | - Antonio Bicchi
- Dipartimento di Ingegneria dell'Informazione, Centro di Ricerca E. Piaggio, Università di Pisa, Pisa, Italy.,Fondazione Istituto Italiano di Tecnologia, Genoa, Italy
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Yu YL, Lan CC. Design of a Miniature Series Elastic Actuator for Bilateral Teleoperations Requiring Accurate Torque Sensing and Control. IEEE Robot Autom Lett 2019. [DOI: 10.1109/lra.2019.2891287] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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43
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Interactive Compliance Control of a Wrist Rehabilitation Device (WR eD) with Enhanced Training Safety. JOURNAL OF HEALTHCARE ENGINEERING 2019; 2019:6537848. [PMID: 30918621 PMCID: PMC6409001 DOI: 10.1155/2019/6537848] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 01/21/2019] [Indexed: 11/25/2022]
Abstract
Interaction control plays an important role in rehabilitation devices to ensure training safety and efficacy. Compliance adaptation of interaction is vital for enabling robot movements to better suit the patient's requirements as human joint characteristics vary. This paper proposes an interactive compliance control scheme on a wrist rehabilitation device (WReD) for enhanced training safety and efficacy. This control system consists of a low-level trajectory tracking loop and a high-level admittance loop. Experiments were conducted with zero load and human interaction, respectively. Satisfactory trajectory tracking responses were obtained, with the normalized root mean square deviation (NRMSD) values being 1.08% with zero load and the NRMSD values no greater than 1.4% with real-time disturbance and interaction from human users. Results demonstrate that such an interactive compliance control method can adaptively adjust the range of training motions and encourage active engagement from human users simultaneously. These findings suggest that the proposed control method of the WReD has great potentials for clinical applications due to enhanced training safety and efficacy. Future work will focus on evaluating its efficacy on a large sample of participants.
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Rahmani M, Rahman MH. An upper-limb exoskeleton robot control using a novel fast fuzzy sliding mode control. JOURNAL OF INTELLIGENT & FUZZY SYSTEMS 2019. [DOI: 10.3233/jifs-181558] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Mehran Rahmani
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, WI, USA
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Active Impedance Control of Bioinspired Motion Robotic Manipulators: An Overview. Appl Bionics Biomech 2018; 2018:8203054. [PMID: 30420899 PMCID: PMC6211161 DOI: 10.1155/2018/8203054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 06/06/2018] [Accepted: 06/24/2018] [Indexed: 11/17/2022] Open
Abstract
There are two main categories of force control schemes: hybrid position-force control and impedance control. However, the former does not take into account the dynamic interaction between the robot's end effector and the environment. In contrast, impedance control includes regulation and stabilization of robot motion by creating a mathematical relationship between the interaction forces and the reference trajectories. It involves an energetic pair of a flow and an effort, instead of controlling a single position or a force. A mass-spring-damper impedance filter is generally used for safe interaction purposes. Tuning the parameters of the impedance filter is important and, if an unsuitable strategy is used, this can lead to unstable contact. Humans, however, have exceptionally effective control systems with advanced biological actuators. An individual can manipulate muscle stiffness to comply with the interaction forces. Accordingly, the parameters of the impedance filter should be time varying rather than value constant in order to match human behavior during interaction tasks. Therefore, this paper presents an overview of impedance control strategies including standard and extended control schemes. Standard controllers cover impedance and admittance architectures. Extended control schemes include admittance control with force tracking, variable impedance control, and impedance control of flexible joints. The categories of impedance control and their features and limitations are well introduced. Attention is paid to variable impedance control while considering the possible control schemes, the performance, stability, and the integration of constant compliant elements with the host robot.
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Du G, Long S, Li F, Huang X. Active Collision Avoidance for Human-Robot Interaction With UKF, Expert System, and Artificial Potential Field Method. Front Robot AI 2018; 5:125. [PMID: 33501004 PMCID: PMC7805694 DOI: 10.3389/frobt.2018.00125] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/11/2018] [Indexed: 11/13/2022] Open
Abstract
With the development of Industry 4.0, the cooperation between robots and people is increasing. Therefore, man-machine security is the first problem that must be solved. In this paper, we proposed a novel methodology of active collision avoidance to safeguard the human who enters the robot's workspace. In the conventional approaches of obstacle avoidance, it is not easy for robots and humans to work safely in the common unstructured environment due to the lack of the intelligence. In this system, one Kinect is employed to monitor the workspace of the robot and detect anyone who enters the workspace of the robot. Once someone enters the working space, the human will be detected, and the skeleton of the human can be calculated in real time by the Kinect. The measurement errors increase over time, owing to the tracking error and the noise of the device. Therefore we use an Unscented Kalman Filter (UKF) to estimate the positions of the skeleton points. We employ an expert system to estimate the behavior of the human. Then let the robot avoid the human by taking different measures, such as stopping, bypassing the human or getting away. Finally, when the robot needs to execute bypassing the human in real time, to achieve this, we adopt a method called artificial potential field method to generate a new path for the robot. By using this active collision avoidance, the system can achieve the purpose that the robot is unable to touch on the human. This proposed system highlights the advantage that during the process, it can first detect the human, then analyze the motion of the human and finally safeguard the human. We experimentally tested the active collision avoidance system in real-world applications. The results of the test indicate that it can effectively ensure human security.
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Affiliation(s)
- Guanglong Du
- School of Computer Science and Engineering, South China University of Technology, Guangzhou, China
| | - Shuaiying Long
- School of Computer Science and Engineering, South China University of Technology, Guangzhou, China
| | - Fang Li
- School of Computer Science and Engineering, South China University of Technology, Guangzhou, China
| | - Xin Huang
- Guangzhou Start to Sail Industrial Robot Co., Ltd, Guangzhou, China
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Sanchez MRA, Leal-Junior AG, Segatto MV, Marques C, Dos Santos WM, Siqueira AAG, Frizera A. Fiber Bragg grating-based sensor for torque and angle measurement in a series elastic actuator's spring. APPLIED OPTICS 2018; 57:7883-7890. [PMID: 30462057 DOI: 10.1364/ao.57.007883] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 08/20/2018] [Indexed: 06/09/2023]
Abstract
Conventional technologies to monitor torque feedback and angle in exoskeleton actuators are bulky and sensitive to misalignments, and do not allow for multiplexed operation. Fiber Bragg grating (FBG)-based sensors are a robust sensing approach that are desirable for multi-parametric monitoring. Temperature, strain, torque, and angle are widely studied in human-robot interaction. In order to acquire the torque and angle of deflection in the torsional spring of a series elastic actuator, an experimental setup with the spring and an array of three FBGs is submitted to repeated torques and angles. This paper presents the characterization and validation of the FBG-based sensor for measuring by torque and angle variations. Temperature cross-sensitivity is derived by the use of a non-strain FBG. The developed sensor presented high linearity and small error for torque and angle measurements.
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Liu Y, Guo S, Hirata H, Ishihara H, Tamiya T. Development of a powered variable-stiffness exoskeleton device for elbow rehabilitation. Biomed Microdevices 2018; 20:64. [PMID: 30074095 DOI: 10.1007/s10544-018-0312-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Robot-assisted movement training by means of exoskeleton devices has been proven to be an effective method for post-stroke patients to recover their motor function. However, in order to be used in home-based rehabilitation, the kinematic structure of a wearable exoskeleton device should provide portability and make allowances for the natural joint range of motion for the user. Additionally, the actuated stiffness of the target joint is desired to be adjustable in accordance with the specific impairment level of the patient's upper limb. In this paper, we present a novel portable exoskeleton device which could provide support for rehabilitation patients with variable actuated stiffness in the elbow joint. It has five passive degrees of freedom to guarantee the user's natural joint range of motion and intra-subject variability, as well as an integrated variable stiffness actuator (VSA) which can adjust the joint stiffness independently by moving the pivot position. An elbow power-assist trial with different actuated joint stiffnesses was tested on a healthy subject to evaluate the functionality of the proposed device. By regulating the joint stiffness, the proposed device could provide variable power assistance for the wearer's elbow movements.
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Affiliation(s)
- Yi Liu
- Graduate School of Engineering, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa, 761-0396, Japan.
| | - Shuxiang Guo
- Key Laboratory of Convergence Medical Engineering System and Healthcare Technology, the Ministry of Industry and Information Technology, Beijing Institute of Technology, No. 5, Zhongguancun South Street, Haidian District, Beijing, 100081, China.
- Faculty of Engineering and Design, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa, 761-0396, Japan.
| | - Hideyuki Hirata
- Faculty of Engineering and Design, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa, 761-0396, Japan
| | - Hidenori Ishihara
- Faculty of Engineering and Design, Kagawa University, 2217-20 Hayashi-cho, Takamatsu, Kagawa, 761-0396, Japan
| | - Takashi Tamiya
- Department of Neurological Surgery, Faculty of Medicine, Kagawa University, 1750-1 Miki-cho, Takamatsu, Kagawa, 761-0701, Japan
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Lee J, Lee C, Tsagarakis N, Oh S. Residual-Based External Torque Estimation in Series Elastic Actuators Over a Wide Stiffness Range: Frequency Domain Approach. IEEE Robot Autom Lett 2018. [DOI: 10.1109/lra.2018.2800128] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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50
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Lee H, Kim HJ, Park J. Control of a nonanthropomorphic exoskeleton for multi-joint assistance by contact force generation. INT J ADV ROBOT SYST 2018. [DOI: 10.1177/1729881418782098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In this article, a novel controller for a nonanthropomorphic exoskeleton robot was designed to reduce joint torque of its operator using the contact force between them. Since the joints of the nonanthropomorphic exoskeletons are not directly connected to those of the operator due to the difference between their kinematic structure, joint assistance is performed by transmitting the contact force on their coupling parts instead of transmitting the joint torque of the nonanthropomorphic exoskeleton directly into the human joint. Most of the previous studies have focused on reducing the measured contact force by moving the coupling parts or commanding the robot joint torque. On the contrary, the proposed method focuses on reducing the human joint torque, which is estimated by formulating inverse dynamics, by obtaining possible contact force solutions. The commanding torque of the nonanthropomorphic exoskeleton was calculated by inverse dynamics based on the model information. To verify the control performance of the proposed method, we have developed a simulation environment for a lower-limb nonanthropomorphic exoskeleton. When the coupling part was implemented to be rigid for an ideal case, the joint torque of the human model to perform the same motion was successfully reduced by the given torque reduction ratio. For a more realistic condition, a nonrigid coupling was also implemented as a virtual spring-damper system, and its effect on the control performance was demonstrated in the simulation.
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Affiliation(s)
- Hosang Lee
- Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
| | - Hyung Joo Kim
- Central Advanced Research and Engineering Institute, Hyundai Motor Company, Seoul, Republic of Korea
| | - Jaeheung Park
- Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
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