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Frontiers of Information Technology & Electronic Engineering >> 2018, Volume 19, Issue 9 doi: 10.1631/FITEE.1601667

Physical human-robot interaction estimation based control scheme for a hydraulically actuated exoskeleton designed for power amplification

1. State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001, China
2. Zhongshan Torch Group Co., Ltd., Zhongshan 528400, China
3. Weapon Equipment Research Institute, China South Industries Group Corporation, Beijing 102202, China

Available online: 2018-12-03

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Abstract

We proposed a lower extremity exoskeleton for power amplification that perceives intended human motion via humanexoskeleton interaction signals measured by biomedical or mechanical sensors, and estimates human gait trajectories to implement corresponding actions quickly and accurately. In this study, torque sensors mounted on the exoskeleton links are proposed for obtaining physical human-robot interaction (pHRI) torque information directly. A Kalman smoother is adopted for eliminating noise and smoothing the signal data. Simultaneously, the mapping from the pHRI torque to the human gait trajectory is defined. The mapping is derived from the real-time state of the robotic exoskeleton during movement. The walking phase is identified by the threshold approach using ground reaction force. Based on phase identification, the human gait can be estimated by applying the proposed algorithm, and then the gait is regarded as the reference input for the controller. A proportional-integral-derivative control strategy is constructed to drive the robotic exoskeleton to follow the human gait trajectory. Experiments were performed on a human subject who walked on the floor at a natural speed wearing the robotic exoskeleton. Experimental results show the effectiveness of the proposed strategy.

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