Abstract: Aiming at the problems of traditional elastic joints, a new elastic joint was proposed, and a two-degree-of-freedom manipulator was designed on the basis.Firstly, the mathematical model of the optimized elastic joint system was analyzed to explore a reliable control mode. Secondly, the mechanical structure design and position control algorithm of the two degree of freedom manipulator were given, and the manipulator prototype was designed. A double loop control scheme was adopted by the control algorithm of the manipulator adopts, in which the model reference adaptive controller (MRAC) was used in the inner loop to deal with the uncertainty of system parameters, and the fuzzy proportional integral controller (FPIC) was used in the outer loop to reduce the influence of external disturbance on the load. Finally, in order to verify the applicability of the control algorithm to elastic joints and manipulators, a computational simulation experiment was carried out on the two-degree-of-freedom manipulator system using MATLAB.The results show that the proposed controller concept has the advantages of fast response and small error. When there is external interference, the response of FPIC-MRAC controller is obviously better than PID controller, and the controller can maintain the stability of the manipulator system. The result verifies the effectiveness of this control algorithm.

Key words: robot actuator; double loop position control algorithm; harmonic drive; planetary transmission mechanism; model reference adaptive control (MRAC); fuzzy proportional integral control (FPIC)