Safety should be at the top of the list in the design of upper limb rehabilitation robots. The Position-controlled upper limb rehabilitation robot can only follow predetermined trajectories to complete rehabilitation training. The motion state of the affected limb is not adjustable with the desired torque of the body, and cannot be trained in accordance to human movement intention. In this paper, a magnetorheological upper limb rehabilitation system (MRRS) based on position control is proposed to achieve better interactivity and safety. The feasibility of motion trajectory is verified by simulation analysis with Matlab/Simulink software. In addition, the adaptive conductivity control method is adopted to realize the desired torque interaction under the action of the internal position closed-loop controller. The adaptive safety control effect of MRRS in acceleration and deceleration conditions under different interaction forces under is studied. The analysis results show that the magnetorheological damper can control the upper limb rehabilitation system to achieve the expected safety control effect when the patient interaction force changes.
 

Magnetorheological dampers, Upper limb rehabilitation, Conductivity control, Safety control