Fundamental study of force control method for pelvis-supporting body weight support system

Takao Watanabe, Eiichi Ohki, Takeshi Ando, Masakatsu G. Fujie

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    7 Citations (Scopus)

    Abstract

    An active body weight support (BWS) system, which unloads body weight with pelvic support, has been developed to assist the walking movement. This system unloads body weight with a motor-actuated device from below with pelvic support, unlike prevailing BWS systems that lift up the subject from above via a harness connected to a wire. The force control method to unload body weight has not been sufficiently studied. As a first step, a comparison study between normal walking and walking with the developed BWS mechanism was conducted to specify the force control method. Since the precise and constant unloading force is believed to be an important prerequisite for BWS gait therapy, different constant unloading forces were set as the target unloading force. The target unloading force was varied from 100 (N) to 300 (N) to observe the difference among forces. The measured unloading forces were not completely constant but fluctuated. The motor introduced a delay at over 200 (N) during lifting. As a result, the floor reaction force was reduced by the target unloading force. However, some differences were found in the bimodal shape of the floor reaction force and the trajectory of the sacrum's vertical position. The results showed the necessity of damping the fluctuation of unloading force by improving following characteristics and adjusting target velocity. Further precise force control will be carried out to realize constant unloading force.

    Original languageEnglish
    Title of host publication2008 IEEE International Conference on Robotics and Biomimetics, ROBIO 2008
    Pages1403-1408
    Number of pages6
    DOIs
    Publication statusPublished - 2008
    Event2008 IEEE International Conference on Robotics and Biomimetics, ROBIO 2008 - Bangkok
    Duration: 2009 Feb 212009 Feb 26

    Other

    Other2008 IEEE International Conference on Robotics and Biomimetics, ROBIO 2008
    CityBangkok
    Period09/2/2109/2/26

    Keywords

    • Dynamic body weight support
    • Force control
    • Pelvic support
    • Treadmill training
    • Walking movement

    ASJC Scopus subject areas

    • Biotechnology
    • Artificial Intelligence
    • Computer Vision and Pattern Recognition
    • Electrical and Electronic Engineering

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  • Cite this

    Watanabe, T., Ohki, E., Ando, T., & Fujie, M. G. (2008). Fundamental study of force control method for pelvis-supporting body weight support system. In 2008 IEEE International Conference on Robotics and Biomimetics, ROBIO 2008 (pp. 1403-1408). [4913206] https://doi.org/10.1109/ROBIO.2009.4913206