Overload Clamping Device Hydraulic Modeling Of Synchronous Drive System And The Internal Model Control Study

Synchronization driving with load balancing of hydraulic system is one of hot spots and difficult problems for heavy-duty gripping devices. The hydraulic driving system of gripper rotational mechanism of 250t forging manipulators is analyzed in this thesis. After the model of the driving system is built, the synchronization driving and load balancing of multi-hydraulic motors are analyzed based on internal model control (IMC) and pressure feedback compensation. The main studies are as follows:(1) The hydraulic driving system of gripper rotational mechanism is proposed and designed based on the basic requirements of synchronization driving and load balancing of heavy-duty gripping devices. Then, the parameters of the hydraulic system and the types of major hydraulic components are determined.(2) The nonlinear model of cartridge electro-hydraulic proportional control valve is built by using power bond graph. According to experimental data, the unknown parameters of this nonlinear model are identified by using least-squares method and the accuracy of the model is proven.(3) The mathematic model of the hydraulic motor system is built by using power bond graph. According to the experimental data, the friction torque model of the motors is obtained. Thus, a more practical model of the hydraulic motor driving system is available.(4) A quasi-affine model of the hydraulic motor driving system is obtained by taking Taylor expansion with respect to the control input at time k-1 for the nonaffine nonlinear hydraulic motor driving system. Then, the nonlinear IMC is designed. Simulation studies show that the IMC has good robustness to disturbances.(5) A synchronization and compensation method is proposed for synchronization driving of multi-systems. The pressure difference of the two motors is calculated as the compensation control signal of one of the two motors. Simulation studies show that the synchronization control system with IMC and pressure feedback compensation has good performance and the requirements of synchronization driving and load balancing can be achieved.