In this paper. an optimal sliding mode control method for trajectory tracking of discrete-time systems based on linear quadratic regulator is proposed to improve the trajectory tracking control accuracy and robustness of upper limb rehabilitation robot under the condition of highly nonlinearities. external disturbances. and unmodeled dynamics. https://www.chiggate.com/turbo-air-m3f72-3-n-78-wide-m3-series-reach-in-freezer-featuring-three-solid-doors-energy-star-online-now/