Output Tracking Performance of Active Exoskeleton Robot Using Sliding Mode Control

Background:: Assistive exoskeleton robot is required to improve the control of exoskeleton joints. The robust response of all joint controls is planned to improve the performance of joint tracking control. Recent patents of an assistive exoskeleton robot concern to explore the system design and integration have been used. Objective:: To design and improve the control performance for gain more stability locomotion of exoskeleton device by using the Sliding Mode Control (SMC) technique, and to explore the recent patents of an assistive exoskeleton robots and methods. Methods:: The recent patents of assistive exoskeleton robots currently investigate in this research. The trajectory generation of gait cycle is approximated using a polynomial equation of the ninth order in the curve fitting of the Human Clinical Gait Cycle (CGC) of lower limb joints. The position and velocity control along the gait cycle are controlled using SMC methods. The robust design of controller performance of position and velocity control for each joint is established via design simulation in three cases. Results:: The output tracking performance of hip, knee, and ankle joint’s position and velocity shows the controller performance. Three cases of control design study are validated by simulation methods. Conclusion:: The SMC controller significantly improves the motion control of exoskeleton robot, even with disturbance affecting the system. Thus, it is robust to external forces with humans in the loop system. A steepest command trajectory will cause a lower output tracking response and vice versa.