Research On Speed Fluctuation Control Of Hybrid-driven Machine

Hybrid-driven mechanism is driven by constant speed motor and servomotor. Inputs from a uniform constant speed motor and a programmable motion servomotor are summed in two degrees of freedom at the output of the linkage. With this machine, the constant speed motor supplies the main torque and power, while the servomotor, which supplies a little part of torque and power, adjusts the output motion. This kind of machine system not only has advantages of classical mechanical system, but also is controllable and has great flexibility. Hybrid-driven seven-bar mechanism is formed by introducing a two linkage bar to five-bar mechanism. This is a new mechanism of simple structure with big flexibility which can generate given path or movement. It has high practical value.This kind of press not only had advantages of classical press system, but also was controllable and had great flexibility with applying hybrid-driven seven-bar mechanism to press, it could provide for programmable motion outputs. Therefore, without changing the geometric parameters of the system, only through adjusting the trajectory of servomotor displacement, the press could meet different material processing requirements.The typical kinetic rules of the mechanical presses were analyzed. Then the feasibility of hybrid-driven seven-bar mechanical presses was discussed. The type of the hybrid-driven mechanical press suitable for deep drawing was selected. The forward and inverse kinematics analysis of the hybrid-driven seven-bar mechanism was made by loop vector method, and the displacement, velocity and acceleration resolution expressions of each part were worked out.In order to realize the flexible output of the slider, the optimum design of the hybrid-driven seven-bar mechanism was carried out through two major processes. The first process was to optimize the geometric parameters of the mechanism, on the assumption that the servomotor rotates at a constant angular velocity equal to the constant velocity motor. The second process was to optimize the displacement trajectory of the servomotor based on the results of the first process while keeping the geometric parameter unchangeable. The input displacement of the servomotor was separately optimized by using polynomial curve. The results pointed out that by adjusting the trajectory of servomotor displacement, the velocity of slider was not only changed, but also achieved different curve of displacement and velocity. It could provide for programmable motion outputs, the flexible output of slider was gained.