An Improved Super-Twisting Sliding Mode for Flexible Upper-Limb Exoskeleton

Aiming at the decrease of tracking accuracy caused by nonlinear friction and strong coupling flexible upper-limb exoskeleton, an improved super-twisting sliding mode controller (ISTSMC) is proposed. Compared with conventional super twisted (STSMC), this method can replace switching function under integral term a nonsmooth term, resulting in faster response, less vibration when performing trajectory tracking, reduced steady-state error. The introduction causes to have stronger anti-interference ability. At same time, parameters ISTSMC be adjusted order achieve expected control performance. effectiveness feasibility proposed algorithm are verified through experiments.