Abstract: In this paper,the minimum joint torque jump measure is proposed and the dynamical fault-tolerant property of redundant robots is researched.At different locked moment,the joint torque based on the expression of joint torque jump is derived.Then the difference between minimum joint torque jump solution and minimum joint velocity jump solution is mathematically analyzed.The result indicates that the minimum joint velocity jump solution is effective to control the end-effectors errors in the case of lower velocity,otherwise the minimum joint torque jump solution is necessary.Finally,a simulation example for a planar 3R redundant robot is presented.