| Each leg of a hydraulic driven foot robot has multiple active degrees of freedom,and each active degree of freedom is generally equipped with a highly integrated hydraulic drive unit,which can greatly improve the work-weight ratio of the robot joint drive.However,most of the hydraulic drive units are throttle valve-controlled cylinder system,which has a large energy loss.However,the pump control system has high efficiency,but the response ability is poor.The valve control system and the pump control system are combined to form a new type of pump valve compound drive system,but the introduction of the pump valve compound drive control system,it brings a series of common problems.These problems undoubtedly increase the difficulty of high precision and high response stress control performance of each joint hydraulic drive unit of the robot.According to the characteristics and control strategy of the pump valve compound driving force control system of the robot joint hydraulic drive unit,the following research work is carried out in this paper,the main contents are as follows:(1)The mathematical modeling and simulation model of the pump valve compound driving force control system are completed.In order to meet the requirements of energy saving,high precision and high response of robot joint hydraulic drive unit,a pump valve compound driving force control system is designed,and the composition and working principle of the system are introduced in detail.The mathematical model of the key components of the pump valve compound drive force control system is established.Through the MATLAB/Simulink simulation platform,the simulation model of the pump valve compound drive force control system is constructed,and the feasibility of the scheme is verified by simulation analysis.(2)The compound control strategy based on nonlinear model is studied.The comprehensive control strategy of each loop is studied,including the tracking error compensation controller and the load compensation controller based on the nonlinear model.The combined control strategy of pump control loop and valve control loop is combined to form the compound control strategy of pump valve compound drive force control system.Finally,the feasibility of the designed control strategy is verified by simulation and the control compensation effect of the control strategy is quantitatively analyzed.(3)The control strategy of QFT-DLOC is studied.Firstly,the mathematical model of the pump control loop is simplified,the open-loop transfer function of the simplified force control system is obtained,and the quantitative feedback controller is designed.Secondly,in order to reduce the influence of disturbance torque on the control performance of servo motor,a disturbance torque observer is designed.Finally,the control effect of QFT-DLOC is verified by simulation and the control compensation effect is analyzed quantitatively.(4)To build the performance test platform of the pump valve compound drive force control system,carry out the related experimental research of the force control system,verify the feasibility of the scheme and the compensation effect of the designed control strategy.The correctness of the principle of the system is verified by experimental conditions.On this basis,the feasibility of composite controller and QFT-DLOC controller based on nonlinear model is verified respectively. |
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