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 to gain more stability locomotion of exoskeleton
device by using the Sliding Mode Control (SMC) technique, and to explore the recent patents of
assistive exoskeleton robots and methods.
Methods: The recent patents of assistive exoskeleton robots were investigated in this research. The trajectory
generation of the gait cycle was 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 were controlled using SMC methods. The robust design of controller performance
of position and velocity control for each joint was 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 the exoskeleton robot,
even with disturbance affecting the system. Thus, it is robust to external forces with humans in the loop
system. The steepest command trajectory will cause a lower output tracking response and vice versa.