Due to the differences in structural design of lower limb rehabilitation robots

the control methods are diversified. A simple control method is proposed to make it move along the planned trajectory for the lower limb rehabilitation robot. In order to design the controller

it is necessary to obtain the inherent transfer function of the robot system at first. After analysis

it is found that the system is a nonlinear system

and its transfer function is approximated via experiments. And then it is changed into a linear control problem. Then pole assignment method is used to design the system as a critically damped second-order system

and the transfer function of the system controller is obtained by backstepping. After testing the hip motion control system of robot

the test results show that the designed controller can meet the requirements.