Abstract: For the safety problem of an assistive robotic manipulator interacting with human in a close range,a safety design method based on collision detection is presented and realized.The collision is detected by the difference of the reference torque calculated according to the manipulator's dynamic model and the actual torque measured by torque sensor. In the design of joint torque sensor,the finite element analysis method is applied to optimizing the pasted position of strain gauge,and meanwhile a signal processing circuit with high disturbance-resisting capacity is developed.According to the low speed characteristic of the assistive robotic manipulator,a simplified dynamic model is established to strike a compromise between efficiency and accuracy of the reference torque computation.Experimental results illustrate the higher sensitivity and real-time performance of the proposed design.