Toward Improving Actuation Transparency and Safety of a Hip Exoskeleton With a Novel Nonlinear Series Elastic Actuator

Qian, Yuepeng1,2,3; Han, Shuaishuai1; Wang, Yining2,3; Yu, Haoyong1; Fu, Chenglong2,3

2022-09-01

10.1109/TMECH.2022.3201255

IEEE-ASME TRANSACTIONS ON MECHATRONICS   Impact Factor & Quartile

1083-4435

1941-014X

Actuation transparency and safety are important requirements in the design and control of assistive exoskeletons for individuals who suffer lower limb deficits but still maintain a certain level of voluntary motor control. In recent years, series elastic actuator (SEA) has been regarded as a promising solution for transparent actuation and safe human-robot interaction, thus SEAs are widely developed and applied in assistive exoskeletons. However, existing SEAs designed for assistive exoskeletons still lack both actuation transparency and safety because of high stiffness of the elastic element and the high mechanical impedance of the actuators. To address this problem, a novel nonlinear SEA (nSEA) is presented in this article. The optimized nonlinear series elastic element coupled with a quasi-direct drive motor creates the nSEA with low mechanical impedance, high backdrivability, and less acoustic noise. Besides, a new torque control, based on cascade PI control, is proposed for the nSEA to control the interaction torque with high accuracy and robustness. Finally, an experimental evaluation with human subjects is performed to validate the advantages of the nSEA-driven hip exoskeleton in the realization of actuation transparency and safety. The root-mean-square interaction torque in zeroimpedance mode is as low as 0.051 N . m during walking conditions, leading to a negligible negative influence on the hip joint's range of motion, walking speed, and energy expenditure when wearing the hip exoskeleton.

Cascade PI control nonlinear series elastic actuator (nSEA) transparent actuation wearable hip exoskeleton

SCI ; EI

English

Corresponding

National Natural Science Foundation of China[U1913205] ; A*star SERC["192 25 00054","192 25 00045"] ; Stable Support Plan Program of Shenzhen Natural Science Fund[20200925174640002] ; Science, Technology and Innovation Commission of Shenzhen Municipality[ZDSYS20200811143601004]

Automation & Control Systems ; Engineering

Automation & Control Systems ; Engineering, Manufacturing ; Engineering, Electrical & Electronic ; Engineering, Mechanical

WOS:000852237800001

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

20223812755576

Acoustic impedance ; Acoustic noise ; Elasticity ; Exoskeleton (Robotics) ; Human robot interaction ; Mechanical actuators ; Perturbation techniques ; Torque ; Two term control systems

Control Systems:731.1 ; Robotics:731.5 ; Control Equipment:732.1 ; Light/Optics:741.1 ; Acoustic Properties of Materials:751.2 ; Acoustic Noise:751.4 ; Mathematics:921 ; Physical Properties of Gases, Liquids and Solids:931.2

ENGINEERING

Web of Science

1.Natl Univ Singapore, Dept Biomed Engn, Singapore 117583, Singapore
2.Southern Univ Sci & Technol, Dept Mech & Energy Engn, Shenzhen Key Lab Biomimet Robot & Intelligent Sys, Shenzhen 518055, Peoples R China
3.Southern Univ Sci & Technol, Guangdong Prov Key Lab Human Augmentat & Rehabil, Dept Mech & Energy Engn, Shenzhen 518055, Peoples R China

Qian, Yuepeng,Han, Shuaishuai,Wang, Yining,et al. Toward Improving Actuation Transparency and Safety of a Hip Exoskeleton With a Novel Nonlinear Series Elastic Actuator[J]. IEEE-ASME TRANSACTIONS ON MECHATRONICS,2022,PP(99):1-12.

Qian, Yuepeng,Han, Shuaishuai,Wang, Yining,Yu, Haoyong,&Fu, Chenglong.(2022).Toward Improving Actuation Transparency and Safety of a Hip Exoskeleton With a Novel Nonlinear Series Elastic Actuator.IEEE-ASME TRANSACTIONS ON MECHATRONICS,PP(99),1-12.

Qian, Yuepeng,et al."Toward Improving Actuation Transparency and Safety of a Hip Exoskeleton With a Novel Nonlinear Series Elastic Actuator".IEEE-ASME TRANSACTIONS ON MECHATRONICS PP.99(2022):1-12.