Decomposed optimal trajectory control of hydraulic actuated quadruped robot based on model prediction

摘要

Hydraulic actuated quadruped robot has strong load capacity, good flexibility, and strong adaptability to complex environments. Pointing at the multi coupling and multi variable characteristics of hydraulic quadruped robot, this paper proposes a decomposed trajectory tracking control strategy based on model prediction for hydraulic quadruped robot. The tracking model is derived by the structure of the hydraulic quadruped robot. The inequality constraints of the quadruped robot motion are built. And the trajectory tracking control problem of the robot is transformed into a quadratic programing problem. The error model of the robot is built. Combining the minimization goals of robot motion speed and acceleration error, the stability and continuity constraints for robot motion are planned. The decomposed trajectory tracking controller with trajectory constraints is designed. The performance of proposed control method is verified by simulation and prototype experiment. The simulation and prototype comparative experiments of classical control strategy and the proposed control strategy are conducted on the hydraulic robot. The results show that compared with the traditional method, the motion trajectory error of the hydraulic robot is relatively small by the proposed optimal trajectory tracking control strategy. The rolling angle accuracy is ±0.066 rad, and the pitching angle accuracy is −0.073 to 0.044 rad. The effectiveness of the proposed control algorithm is verified by the simulation and experimental results. The accuracy of the hydraulic robot model in the control algorithm is improved, the impact during hydraulic robot motion is reduced, and the service life of the robot was increased, as well as the stability of robot motion is enhanced.