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Mohammadi Nejad Rashty A, Sharbafi MA, Mohseni O, Seyfarth A. Role of compliant mechanics and motor control in hopping - from human to robot. Sci Rep 2024; 14:6820. [PMID: 38514699 PMCID: PMC10957903 DOI: 10.1038/s41598-024-57149-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 03/14/2024] [Indexed: 03/23/2024] Open
Abstract
Compliant leg function found during bouncy gaits in humans and animals can be considered a role model for designing and controlling bioinspired robots and assistive devices. The human musculoskeletal design and control differ from distal to proximal joints in the leg. The specific mechanical properties of different leg parts could simplify motor control, e.g., by taking advantage of passive body dynamics. This control embodiment is complemented by neural reflex circuitries shaping human motor control. This study investigates the contribution of specific passive and active properties at different leg joint levels in human hopping at different hopping frequencies. We analyze the kinematics and kinetics of human leg joints to design and control a bioinspired hopping robot. In addition, this robot is used as a test rig to validate the identified concepts from human hopping. We found that the more distal the joint, the higher the possibility of benefit from passive compliant leg structures. A passive elastic element nicely describes the ankle joint function. In contrast, a more significant contribution to energy management using an active element (e.g., by feedback control) is predicted for the knee and hip joints. The ankle and knee joints are the key contributors to adjusting hopping frequency. Humans can speed up hopping by increasing ankle stiffness and tuning corresponding knee control parameters. We found that the force-modulated compliance (FMC) as an abstract reflex-based control beside a fixed spring can predict human knee torque-angle patterns at different frequencies. These developed bioinspired models for ankle and knee joints were applied to design and control the EPA-hopper-II robot. The experimental results support our biomechanical findings while indicating potential robot improvements. Based on the proposed model and the robot's experimental results, passive compliant elements (e.g. tendons) have a larger capacity to contribute to the distal joint function compared to proximal joints. With the use of more compliant elements in the distal joint, a larger contribution to managing energy changes is observed in the upper joints.
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Affiliation(s)
- Aida Mohammadi Nejad Rashty
- Lauflabor Locomotion Laboratory, Institute of Sport Science and Centre for Cognitive Science, Technical University of Darmstadt, Darmstadt, 64289, Germany.
| | - Maziar A Sharbafi
- Lauflabor Locomotion Laboratory, Institute of Sport Science and Centre for Cognitive Science, Technical University of Darmstadt, Darmstadt, 64289, Germany
| | - Omid Mohseni
- Lauflabor Locomotion Laboratory, Institute of Sport Science and Centre for Cognitive Science, Technical University of Darmstadt, Darmstadt, 64289, Germany
| | - André Seyfarth
- Lauflabor Locomotion Laboratory, Institute of Sport Science and Centre for Cognitive Science, Technical University of Darmstadt, Darmstadt, 64289, Germany
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Silva AB, Murcia M, Mohseni O, Takahashi R, Forner-Cordero A, Seyfarth A, Hosoda K, Sharbafi MA. Design of Low-Cost Modular Bio-Inspired Electric-Pneumatic Actuator (EPA)-Driven Legged Robots. Biomimetics (Basel) 2024; 9:164. [PMID: 38534849 DOI: 10.3390/biomimetics9030164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 02/29/2024] [Accepted: 03/04/2024] [Indexed: 03/28/2024] Open
Abstract
Exploring the fundamental mechanisms of locomotion extends beyond mere simulation and modeling. It necessitates the utilization of physical test benches to validate hypotheses regarding real-world applications of locomotion. This study introduces cost-effective modular robotic platforms designed specifically for investigating the intricacies of locomotion and control strategies. Expanding upon our prior research in electric-pneumatic actuation (EPA), we present the mechanical and electrical designs of the latest developments in the EPA robot series. These include EPA Jumper, a human-sized segmented monoped robot, and its extension EPA Walker, a human-sized bipedal robot. Both replicate the human weight and inertia distributions, featuring co-actuation through electrical motors and pneumatic artificial muscles. These low-cost modular platforms, with considerations for degrees of freedom and redundant actuation, (1) provide opportunities to study different locomotor subfunctions-stance, swing, and balance; (2) help investigate the role of actuation schemes in tasks such as hopping and walking; and (3) allow testing hypotheses regarding biological locomotors in real-world physical test benches.
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Affiliation(s)
- Alessandro Brugnera Silva
- Lauflabor Locomotion Laboratory, Centre for Cognitive Science, Technical University of Darmstadt, 64289 Darmstadt, Germany
- Biomechatronics Laboratory, Department of Mechatronics and Mechanical Systems of the Polytechnic School of the University of São Paulo (USP), São Paulo 05508-030, SP, Brazil
| | - Marc Murcia
- Lauflabor Locomotion Laboratory, Centre for Cognitive Science, Technical University of Darmstadt, 64289 Darmstadt, Germany
| | - Omid Mohseni
- Lauflabor Locomotion Laboratory, Centre for Cognitive Science, Technical University of Darmstadt, 64289 Darmstadt, Germany
| | - Ryu Takahashi
- Adaptive Robotics Laboratory, Graduate School of Engineering Science, Osaka University, Toyonaka 560-0043, Japan
| | - Arturo Forner-Cordero
- Biomechatronics Laboratory, Department of Mechatronics and Mechanical Systems of the Polytechnic School of the University of São Paulo (USP), São Paulo 05508-030, SP, Brazil
| | - Andre Seyfarth
- Lauflabor Locomotion Laboratory, Centre for Cognitive Science, Technical University of Darmstadt, 64289 Darmstadt, Germany
| | - Koh Hosoda
- Adaptive Robotics Laboratory, Graduate School of Engineering Science, Osaka University, Toyonaka 560-0043, Japan
- Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Maziar Ahmad Sharbafi
- Lauflabor Locomotion Laboratory, Centre for Cognitive Science, Technical University of Darmstadt, 64289 Darmstadt, Germany
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Zhao G, Mohseni O, Murcia M, Seyfarth A, Sharbafi MA. Exploring the effects of serial and parallel elasticity on a hopping robot. Front Neurorobot 2022; 16:919830. [PMID: 36091418 PMCID: PMC9449899 DOI: 10.3389/fnbot.2022.919830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 07/25/2022] [Indexed: 11/30/2022] Open
Abstract
The interaction between the motor control and the morphological design of the human leg is critical for generating efficient and robust locomotion. In this paper, we focus on exploring the effects of the serial and parallel elasticity on hopping with a two-segmented robotic leg called electric-pneumatic actuation (EPA)-Hopper. EPA-Hopper uses a hybrid actuation system that combines electric motors and pneumatic artificial muscles (PAM). It provides direct access to adjust the physical compliance of the actuation system by tuning PAM pressures. We evaluate the role of the serial and parallel PAMs with different levels of compliance with respect to four criteria: efficiency, performance, stability, and robustness of hopping against perturbations. The results show that the serial PAM has a more pronounced impact than the parallel PAM on these criteria. Increasing the stiffness of the serial PAM decreases the leg stiffness of the unloading phase during hopping. The stiffer the leg, the more efficient and the less robust the movement. These findings can help us further understand the human hopping mechanism and support the design and control of legged robots and assistive devices.
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Seyfarth A, Zhao G, Jörntell H. Whole Body Coordination for Self-Assistance in Locomotion. Front Neurorobot 2022; 16:883641. [PMID: 35747075 PMCID: PMC9211759 DOI: 10.3389/fnbot.2022.883641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 05/12/2022] [Indexed: 12/03/2022] Open
Abstract
The dynamics of the human body can be described by the accelerations and masses of the different body parts (e.g., legs, arm, trunk). These body parts can exhibit specific coordination patterns with each other. In human walking, we found that the swing leg cooperates with the upper body and the stance leg in different ways (e.g., in-phase and out-of-phase in vertical and horizontal directions, respectively). Such patterns of self-assistance found in human locomotion could be of advantage in robotics design, in the design of any assistive device for patients with movement impairments. It can also shed light on several unexplained infrastructural features of the CNS motor control. Self-assistance means that distributed parts of the body contribute to an overlay of functions that are required to solve the underlying motor task. To draw advantage of self-assisting effects, precise and balanced spatiotemporal patterns of muscle activation are necessary. We show that the necessary neural connectivity infrastructure to achieve such muscle control exists in abundance in the spinocerebellar circuitry. We discuss how these connectivity patterns of the spinal interneurons appear to be present already perinatally but also likely are learned. We also discuss the importance of these insights into whole body locomotion for the successful design of future assistive devices and the sense of control that they could ideally confer to the user.
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Affiliation(s)
- André Seyfarth
- Lauflabor Locomotion Laboratory, Institute of Sport Science and Centre for Cognitive Science, Technische Universität Darmstadt, Darmstadt, Germany
- *Correspondence: André Seyfarth
| | - Guoping Zhao
- Lauflabor Locomotion Laboratory, Institute of Sport Science and Centre for Cognitive Science, Technische Universität Darmstadt, Darmstadt, Germany
| | - Henrik Jörntell
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, Lund, Sweden
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Mohseni O, Schmidt P, Seyfarth A, Sharbafi MA. Unified GRF-based control for adjusting hopping frequency with various robot configurations. Adv Robot 2022. [DOI: 10.1080/01691864.2022.2077637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Omid Mohseni
- Lauflabor Locomotion Laboratory, Centre for Cognitive Science, TU Darmstadt, Darmstadt, Germany
| | - Patrick Schmidt
- Lauflabor Locomotion Laboratory, Centre for Cognitive Science, TU Darmstadt, Darmstadt, Germany
| | - Andre Seyfarth
- Lauflabor Locomotion Laboratory, Centre for Cognitive Science, TU Darmstadt, Darmstadt, Germany
| | - Maziar A. Sharbafi
- Lauflabor Locomotion Laboratory, Centre for Cognitive Science, TU Darmstadt, Darmstadt, Germany
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Abstract
AbstractIn order to approach the performance of biological locomotion in legged robots, better integration between body design and control is required. In that respect, understanding the mechanics and control of human locomotion will help us build legged robots with comparable efficient performance. From another perspective, developing bioinspired robots can also improve our understanding of human locomotion. In this work, we create a bioinspired robot with a blended physical and virtual impedance control to configure the robot’s mechatronic setup. We consider human neural control and musculoskeletal system a blueprint for a hopping robot. The hybrid electric-pneumatic actuator (EPA) presents an artificial copy of this biological system to implement the blended control. By defining efficacy as a metric that encompasses both performance and efficiency, we demonstrate that incorporating a simple force-based control besides constant pressure pneumatic artificial muscles (PAM) alone can increase the efficiency up to 21% in simulations and 7% in experiments with the 2-segmented EPA-hopper robot. Also, we show that with proper adjustment of the force-based controller and the PAMs, efficacy can be further increased to 41%. Finally, experimental results with the 3-segmented EPA-hopper robot and comparisons with human hopping confirm the extendability of the proposed methods to more complex robots.
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Bohler TE, Brown RF, Dunn S. Relationship between affective state and empathy in medical and psychology students. AUSTRALIAN PSYCHOLOGIST 2021. [DOI: 10.1080/00050067.2021.1926218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Tamara E. Bohler
- Medical School, Australian National University, Canberra, Australia
| | - Rhonda F. Brown
- Research School of Psychology, Australian National University, Canberra, Australia
| | - Stewart Dunn
- Psychological Medicine, University of Sydney, Sydney, Australia
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Zhao G, Szymanski F, Seyfarth A. Bio-inspired neuromuscular reflex based hopping controller for a segmented robotic leg. BIOINSPIRATION & BIOMIMETICS 2020; 15:026007. [PMID: 31968325 DOI: 10.1088/1748-3190/ab6ed8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
It has been shown that human-like hopping can be achieved by muscle reflex control in neuromechanical simulations. However, it is unclear if this concept is applicable and feasible for controlling a real robot. This paper presents a low-cost two-segmented robotic leg design and demonstrates the feasibility and the benefits of the bio-inspired neuromuscular reflex based control for hopping. Simulation models were developed to describe the dynamics of the real robot. Different neuromuscular reflex pathways were investigated with the simulation models. We found that stable hopping can be achieved with both positive muscle force and length feedback, and the hopping height can be controlled by modulating the muscle force feedback gains with the return maps. The force feedback neuromuscular reflex based controller is robust against body mass and ground impedance changes. Finally, we implemented the controller on the real robot to prove the feasibility of the proposed neuromuscular reflex based control idea. This paper demonstrates the neuromuscular reflex based control approach is feasible to implement and capable of achieving stable and robust hopping in a real robot. It provides a promising direction of controlling the legged robot to achieve robust dynamic motion in the future.
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Affiliation(s)
- Guoping Zhao
- Author to whom any correspondence should be addressed
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Oehlke J, Beckerle P, Seyfarth A, Sharbafi MA. Human-like hopping in machines : Feedback- versus feed-forward-controlled motions. BIOLOGICAL CYBERNETICS 2019; 113:227-238. [PMID: 30370464 PMCID: PMC6510817 DOI: 10.1007/s00422-018-0788-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 10/21/2018] [Indexed: 06/08/2023]
Abstract
Template models of legged locomotion are powerful tools for gait analysis, but can also inspire robot design and control. In this paper, a spring-loaded inverted pendulum (SLIP) model is employed to control vertical hopping of a 2-segmented legged robot. Feed-forward and bio-inspired virtual model control using the SLIP model are compared. In the latter approach, the feedback control emulates a virtual spring between hip and foot. The results demonstrate similarity of human and robot hopping. Moreover, the feedback control proves to simplify and improve hopping control. It yields better perturbation recovery and locomotion adaptation and is even easier to tune. Thus, human-like hopping is achievable using a rather simple template-based controller, which ensures the required performance, robustness and versatility.
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Affiliation(s)
- Jonathan Oehlke
- Institut für Mechatronische Systeme im Maschinenbau, Technische Universität Darmstadt, Otto-Berndt-Straße 2, 64287, Darmstadt, Germany
| | - Philipp Beckerle
- Institut für Mechatronische Systeme im Maschinenbau, Technische Universität Darmstadt, Otto-Berndt-Straße 2, 64287, Darmstadt, Germany
- Elastic Lightweight Robotics Group, Robotics Research Institute, Technische Universität Dortmund, Otto-Hahn-Straße 8, 44221, Dortmund, Germany
| | - André Seyfarth
- Lauflabor Locomotion Laboratory, Institute of Sport Science, TU Darmstadt, Magdalenenstr. 27, 64289, Darmstadt, Germany
| | - Maziar A Sharbafi
- Lauflabor Locomotion Laboratory, Institute of Sport Science, TU Darmstadt, Magdalenenstr. 27, 64289, Darmstadt, Germany.
- Control & Intelligent Processing Center of Excellence and the School of Electrical and Computer Engineering, College of Engineering, University of Tehran, 14395-515, Tehran, Iran.
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Davoodi A, Mohseni O, Seyfarth A, Sharbafi MA. From template to anchors: transfer of virtual pendulum posture control balance template to adaptive neuromuscular gait model increases walking stability. ROYAL SOCIETY OPEN SCIENCE 2019; 6:181911. [PMID: 31032044 PMCID: PMC6458364 DOI: 10.1098/rsos.181911] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 02/08/2019] [Indexed: 06/09/2023]
Abstract
Biomechanical models with different levels of complexity are of advantage to understand the underlying principles of legged locomotion. Following a minimalistic approach of gradually increasing model complexity based on Template & Anchor concept, in this paper, a spring-loaded inverted pendulum-based walking model is extended by a rigid trunk, hip muscles and reflex control, called nmF (neuromuscular force modulated compliant hip) model. Our control strategy includes leg force feedback to activate hip muscles (originated from the FMCH approach), and a discrete linear quadratic regulator for adapting muscle reflexes. The nmF model demonstrates human-like walking kinematic and dynamic features such as the virtual pendulum (VP) concept, inherited from the FMCH model. Moreover, the robustness against postural perturbations is two times higher in the nmF model compared to the FMCH model and even further increased in the adaptive nmF model. This is due to the intrinsic muscle dynamics and the tuning of the reflex gains. With this, we demonstrate, for the first time, the evolution of mechanical template models (e.g. VP concept) to a more physiological level (nmF model). This shows that the template model can be successfully used to design and control robust locomotor systems with more realistic system behaviours.
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Affiliation(s)
- Ayoob Davoodi
- School of ECE, Control and Intelligent Processing Center of Excellence (CIPCE), College of Engineering, University of Tehran, Tehran, Iran
| | - Omid Mohseni
- School of ECE, Control and Intelligent Processing Center of Excellence (CIPCE), College of Engineering, University of Tehran, Tehran, Iran
| | - Andre Seyfarth
- Lauflabor Locomotion Lab, Centre for Cognitive Science, TU Darmstadt, Germany
| | - Maziar A. Sharbafi
- School of ECE, Control and Intelligent Processing Center of Excellence (CIPCE), College of Engineering, University of Tehran, Tehran, Iran
- Lauflabor Locomotion Lab, Centre for Cognitive Science, TU Darmstadt, Germany
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