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Jenkinson GP, Conn AT, Tzemanaki A. ESPRESS.0: Eustachian Tube-Inspired Tactile Sensor Exploiting Pneumatics for Range Extension and SenSitivity Tuning. SENSORS (BASEL, SWITZERLAND) 2023; 23:567. [PMID: 36679363 PMCID: PMC9860791 DOI: 10.3390/s23020567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
Optimising the sensitivity of a tactile sensor to a specific range of stimuli magnitude usually compromises the sensor's widespread usage. This paper presents a novel soft tactile sensor capable of dynamically tuning its stiffness for enhanced sensitivity across a range of applied forces, taking inspiration from the Eustachian tube in the mammalian ear. The sensor exploits an adjustable pneumatic back pressure to control the effective stiffness of its 20 mm diameter elastomer interface. An internally translocated fluid is coupled to the membrane and optically tracked to measure physical interactions at the interface. The sensor can be actuated by pneumatic pressure to dynamically adjust its stiffness. It is demonstrated to detect forces as small as 0.012 N, and to be sensitive to a difference of 0.006 N in the force range of 35 to 40 N. The sensor is demonstrated to be capable of detecting tactile cues on the surface of objects in the sub-millimetre scale. It is able to adapt its compliance to increase its ability for distinguishing between stimuli with similar stiffnesses (0.181 N/mm difference) over a large range (0.1 to 1.1 N/mm) from only a 0.6 mm deep palpation. The sensor is intended to interact comfortably with skin, and the feasibility of its use in palpating tissue in search of hard inclusions is demonstrated by locating and estimating the size of a synthetic hard node embedded 20 mm deep in a soft silicone sample. The results suggest that the sensor is a good candidate for tactile tasks involving unpredictable or unknown stimuli.
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Affiliation(s)
- George P. Jenkinson
- Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, UK
| | | | - Antonia Tzemanaki
- Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, UK
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Liu H, Laflamme S, Zellner EM, Aertsens A, Bentil SA, Rivero IV, Secord TW. Soft Elastomeric Capacitor for Strain and Stress Monitoring on Sutured Skin Tissues. ACS Sens 2021; 6:3706-3714. [PMID: 34582189 DOI: 10.1021/acssensors.1c01477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sutures are ubiquitous medical devices for wound closures in human and veterinary medicine, and suture techniques are frequently evaluated by comparing tensile strengths in ex vivo studies. Direct and nondestructive measurement of tensile force present in sutured biological skin tissue is a key challenge in biomechanical fields because of the unique and complex properties of each sutured skin specimen and the lack of compliant sensors capable of monitoring large levels of strain. The authors have recently proposed a soft elastomeric capacitor (SEC) sensor that consists of a highly compliant and scalable strain gauge capable of transducing geometric variations into a measurable change in capacitance. In this study, corrugated SECs are used to experimentally characterize the inherent biomechanical properties of canine skin specimens. In particular, an SEC corrugated with a re-entrant hexagonal honeycomb pattern is studied to monitor strain and stresses for three specific suture patterns: simple interrupted, cruciate, and intradermal patterns. Stress is estimated using constitutive models based on the Fractional Zener and the Kelvin-Voigt models, parametrized using a particle swarm algorithm from experimental data and results from a validated finite element model. Results are benchmarked against findings from the literature and show that SECs are valuable for clinical evaluation of tensile force in biological skins. It was found that both the ranking of suture pattern performance and the sutured skin's Young's modulus using the proposed approach agreed with data reported in the literature and that the estimated stress at the suture level closely matched that of an approximate finite element model.
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Affiliation(s)
- Han Liu
- Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Simon Laflamme
- Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Eric M. Zellner
- Veterinary Clinical Sciences, Iowa State University, Ames, Iowa 50011, United States
| | - Adrien Aertsens
- Veterinary Clinical Sciences, Iowa State University, Ames, Iowa 50011, United States
| | - Sarah A. Bentil
- Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011, United States
| | - Iris V. Rivero
- Department of Industrial and Systems Engineering, Rochester Institute of Technology, Rochester, New York 14623, United States
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, New York 14623, United States
| | - Thomas W. Secord
- Department of Mechanical Engineering, University of St. Thomas, St. Paul, Minnesota 55105, United States
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Bewley J, Jenkinson GP, Tzemanaki A. Optical-Tactile Sensor for Lump Detection Using Pneumatic Control. Front Robot AI 2021; 8:672315. [PMID: 34277716 PMCID: PMC8281246 DOI: 10.3389/frobt.2021.672315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 06/16/2021] [Indexed: 11/28/2022] Open
Abstract
Soft tactile sensors are an attractive solution when robotic systems must interact with delicate objects in unstructured and obscured environments, such as most medical robotics applications. The soft nature of such a system increases both comfort and safety, while the addition of simultaneous soft active actuation provides additional features and can also improve the sensing range. This paper presents the development of a compact soft tactile sensor which is able to measure the profile of objects and, through an integrated pneumatic system, actuate and change the effective stiffness of its tactile contact surface. We report experimental results which demonstrate the sensor's ability to detect lumps on the surface of objects or embedded within a silicone matrix. These results show the potential of this approach as a versatile method of tactile sensing with potential application in medical diagnosis.
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Affiliation(s)
- Jonathan Bewley
- Department of Mechanical Engineering, Faculty of Engineering, University of Bristol, Bristol, United Kingdom
| | - George P. Jenkinson
- Department of Mechanical Engineering, Faculty of Engineering, University of Bristol, Bristol, United Kingdom
- Bristol Robotics Laboratory, University of Bristol, Bristol, United Kingdom
| | - Antonia Tzemanaki
- Department of Mechanical Engineering, Faculty of Engineering, University of Bristol, Bristol, United Kingdom
- Bristol Robotics Laboratory, University of Bristol, Bristol, United Kingdom
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Li C, Lü G, Shen J. Tactile sensor with an inverted V-shaped indenter for elastic tissue identification. INTEL SERV ROBOT 2019. [DOI: 10.1007/s11370-019-00304-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Formulation and statistical evaluation of an automated algorithm for locating small bowel tumours in wireless capsule endoscopy. Biocybern Biomed Eng 2018. [DOI: 10.1016/j.bbe.2018.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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