Research On Electro-hydraulic Servo Actuator Control Of Hydraulic Quadruped Robot

With the exploration of the robot research and the extension of the application fields,bionic robot has been widely used in military operations,medical,fire relief and extraterrestrial detection.In the environmental adaptability,flexibility and load ability,etc.,the legged robot has outstanding performance.Electro-hydraulic servo actuator is the joint driving unit of the hydraulic quadruped robot,which performance directly affects the dynamic performance and motion stability of the robot.Therefore,in view of the importance of the electro-hydraulic servo actuator in the motion control of the quadruped robot,this thesis makes in-depth researches on the electro-hydraulic servo actuator position control and driving force control of the hydraulic quadruped robot.According to the structure characteristics of the robot legs which are drived by electro-hydraulic actuator,the mathematical models of electro-hydraulic actuator position and driving force control system is established by theoretical analysis.Aiming at the problems of time-varying and uncertainty,model parameters are identified and the accuracy of the identification model is verified to obtain the more accurate mathematical model of electro-hydraulic servo actuator,which provides theoretical basis for the controller design and simulation analysis.For the residual vibration problems of the position control of robot joint,input shaping control strategy is applied to the position control of electrohydraulic servo actuator.At the same time,command shaping controller is designed to suppress or eliminate the residual vibration of system.Then,AMESim and Simulink are combined to carry out the coordinated simulation for verifying the control strategy.In order to improve the control precision of the driving force control ofrobot joint,the sliding mode control strategy is applied to the driving force control of electro-hydraulic servo actuator.For the vibrations problems of sliding mode control,fuzzy sliding mode control strategy which combines fuzzy control and sliding mode control is proposed,moreover,simulation analysis of the controller is carried out for verifying the effectiveness of the control strategy.The effectiveness and reliability of the proposed control techniques for position control and driving force control of robot joint on the actual system are verified on single leg test platform of hydraulic quadruped robot which is established by the laboratory of Harbin University of Science and Technology.