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A novel hybrid closed-loop control approach for dexterous prosthetic hand based on myoelectric control and electrical stimulation

Li Jiang (State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, China)
Qi Huang (State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, China)
Dapeng Yang (State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, China and Artificial Intelligence Laboratory, Harbin Institute of Technology, Harbin, China)
Shaowei Fan (State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, China)
Hong Liu (State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, China)

Industrial Robot

ISSN: 0143-991x

Article publication date: 11 June 2018

Issue publication date: 29 August 2018

231

Abstract

Purpose

The purpose of this study is to present a novel hybrid closed-loop control method together with its performance validation for the dexterous prosthetic hand.

Design/methodology/approach

The hybrid closed-loop control is composed of a high-level closed-loop control with the user in the closed loop and a low-level closed-loop control for the direct robot motion control. The authors construct the high-level control loop by using electromyography (EMG)-based human motion intent decoding and electrical stimulation (ES)-based sensory feedback. The human motion intent is decoded by a finite state machine, which can achieve both the patterned motion control and the proportional force control. The sensory feedback is in the form of transcutaneous electrical nerve stimulation (TENS) with spatial-frequency modulation. To suppress the TENS interfering noise, the authors propose biphasic TENS to concentrate the stimulation current and the variable step-size least mean square adaptive filter to cancel the noise. Eight subjects participated in the validation experiments, including pattern selection and egg grasping tasks, to investigate the feasibility of the hybrid closed-loop control in clinical use.

Findings

The proposed noise cancellation method largely reduces the ES noise artifacts in the EMG electrodes by 18.5 dB on average. Compared with the open-loop control, the proposed hybrid closed-loop control method significantly improves both the pattern selection efficiency and the egg grasping success rate, both in blind operating scenarios (improved by 1.86 s, p < 0.001, and 63.7 per cent, p < 0.001) or in common operating scenarios (improved by 0.49 s, p = 0.008, and 41.3 per cent, p < 0.001).

Practical implications

The proposed hybrid closed-loop control method can be implemented on a prosthetic hand to improve the operation efficiency and accuracy for fragile objects such as eggs.

Originality/value

The primary contribution is the proposal of the hybrid closed-loop control, the spatial-frequency modulation method for the sensory feedback and the noise cancellation method for the integrating of the myoelectric control and the ES-based sensory feedback.

Keywords

Acknowledgements

This work is partially supported by the National Natural Science Foundation of China (No. 51675123, 61603112), the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (Grant No. 51521003), the National Basic Research Program (973 Program) of China (No. 2011CB013306) and the Research Fund for the Doctoral Program of Higher Education of China (No. 20132302110034).

Citation

Jiang, L., Huang, Q., Yang, D., Fan, S. and Liu, H. (2019), "A novel hybrid closed-loop control approach for dexterous prosthetic hand based on myoelectric control and electrical stimulation", Industrial Robot, Vol. 45 No. 4, pp. 526-538. https://doi.org/10.1108/IR-12-2017-0209

Publisher

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Emerald Publishing Limited

Copyright © 2018, Emerald Publishing Limited

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