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Observer Sliding Mode Control Design for lower Exoskeleton system: Rehabilitation Case Nasir Ahmed Alawad; Amjad J. Humaidi; Ahmed Sabah Alaraji
Journal of Robotics and Control (JRC) Vol 3, No 4 (2022): July
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/jrc.v3i4.15239

Abstract

Sliding mode (SM) has been selected as the controlling technique, and the state observer (SO) design is used as a component of active disturbance rejection control (ADRC) to reduce the knee position trajectory for therapeutic purposes. The suggested controller will improve the needed position performances for the Exoskeleton system when compared to the proportional-derivative controller (PD) and SMC as feed-forward in the ADRC approach, as shown theoretically and through computer simulations. Simulink tool is used in this comparison to analyze the nominal case and several disruption cases. The results of mathematical modeling and simulation studies demonstrated that SMC with a disturbance observer strategy performs better than the PD control system and SMC in feed-forward with a greater capacity to reject disturbances and significantly better than these controllers. Performance indices are used for numerical comparison to demonstrate the superiority of these controllers.
Fractional proportional derivative-based active disturbance rejection control of knee exoskeleton device for rehabilitation care Nasir Ahmed Alawad; Amjad Jaleel Humaidi; Ahmed Sabah Alaraji
Indonesian Journal of Electrical Engineering and Computer Science Vol 28, No 3: December 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v28.i3.pp1405-1413

Abstract

The use of rehabilitation exoskeleton by physiotherapists in their daily practice is becoming more common. In this study, the active disturbance rejection controller (ADRC) is proposed to ensure high performance of trajectory tracking for asstitve exoskeleton at the level of knee-joint. The controlled medical robot has to mimic the actual physical training and application for knee-rehabilitation. Two versions of ADRC is presented to control the rehabilitation system. One version is based on conventional ADRC, while the other version is based on fractional proportional-derivative PD-ADRC. A comparison study in performance has been conducted between two versions of ADRCs in terms of robustness against disturbances. According to numerical simulations, the results showed that the fractional PD-based ADRC ouptperforms the ADRC in terms of robustness characteritics based on the index root mean square error (RMSE).