Optimal Control Of Hybrid-Driven Precision Press

The hybrid-driven precision press combines the motion of a large uncontrollable constant speed motor and that of a small controllable servomotor via a two-DOF mechanism into flexible motion of a slider. In this system, the constant speed motor satisfies main requirements of torque and motion, while the servomotor contributes to modulation on this motion. This dissertation focuses on the optimal control of the hybrid-driven precision press. The major achievements are listed as follows:1. The forward and inverse kinematics of the hybrid-driven precision press is analyzed. Given the motion of the cranks driven by constant speed motor and servomotor, that of slider and other links is obtained with forward kinematics. Given the motion of the crank driven by constant motor and the slider, that of the crank driven by servomotor and other links is obtained with inverse kinematics.2. Based on the kinematic analysis, the motion of centroids of all links is obtained, then the dynamic model of the hybrid-driven precision press is established with virtual work principle.3. Firstly, the optimal control model of the precision press is set up. Based on the calculus of variation, its optimal solution is obtained. Secondly, the question on optimal control is transformed into a question on boundary condition. Then, based on the conjugate function algorithm, its numerical solution is obtained. Lastly, validity and advantage of optimal control is proved by comparing simulation results of optimal control and PID control.4. At the end of the dissertation, some suggestion is given for further study of the hybrid-driven precision press and its control.