Abstract: Based on the screw theory， the concepts of motion screw， force screw and partial velocity screw were introduced. Then Kane dynamic equations were derived for an upper limb rehabilitation robot with 5 DOF. Simulation results show that dynamics analysis for the robot based on the screw theory is more concise and explicit than that based on the DH method in which local coordinate systems are used. The solution of Kane equations only involves addition， subtraction and multiplication， so the method has higher calculation efficiency than nonlinear Lagrange and NewtonEuler dynamic equations and is easier to implement real time control. The robotic joint curves of angular displacements， angular velocities， angular accelerations were studied by simulation from initial configuration to ready configuration. The conclusion validates the correctness and effectiveness of Kane equations based on the screw theory.

Key words: upper limb rehabilitation robot, screw theory, partial velocity screw, dynamics, Kane equations