Overloaded Clamping Device Dual Motor Backlash Transmission System Modeling And Control

The design and control strategies of the rotational driving system for the grippers of 250 Ton forging manipulators were studied in this thesis. The system has the features such as large inertia, large variation of load, nonlinearities of hydraulic part, dead zone of control valve, gear backlash and nonlinear of friction torque. It is difficult to meet the requirement of fast accelerating, fast retarding and precise positioning. A function exchangeable driving system with two motors was proposed in combination with the requirements and features of forging manipulator gripper driving system to eliminate the effect of gear backlash. The main studies are as follows:1,A two motors driving system was proposed for eliminating the effect of backlash. A single motor driving system which can not eliminate the effect of gear backlash was also built to compare with the double motor driving system. The nonlinear models of the driving systems were established.2,The parameters of the cartridge valve were identified by the least square method based on the frequency responses and step responses. The frictional torque model of the motors was also set up based on experimental data.3,The fuzzy adaptive tuning PID controller was applied to the control of the driving system. The comparison between conventional PID and fuzzy PID shows that fuzzy PID has better control performance for systems with dead-zone of control valve, gear backlash and friction nonlinearities. The accumulated error of the gripper driving system can be eliminated and requirement of precision can be met.4,The comparison between gripper rotational driving systems with and without gear backlash shows that gear backlash affects the performance of system significantly and the driving system with double motors can eliminate the effect of gear backlash on the system.The analysis of simulation results indicates that the proposed double motor driving system can meet the requirement of response speed and control precision. Moreover, the system has the features such as smoothness of fast response and strong anti-interference capability.