Abstract:

A new optimal cam profile design method was proposed based on the mechanism dynamics and control system co-simulation and optimization to reduce the contact force of the mould dies driven by the can mechanism in a high-speed bottle blowing machine. An optimization model was built for the bottle flowing machine dies motion control system, its objective function is to minimize the time of the bottle die clamping motion under restraint of maximum contact force. A state variable of the displacement of bottle die was introduced based on the relationship between the contact force and contact information according to Hertz contact theory, the high-speed impact-free cam profile design problem was transformed to the fastest control problem without displacement overshooting. The control system parameters and the motion velocity for the fastest motion under restraint of non-overshooting were obtained by the mechanism dynamics and control system co-simulation and optimization, and the control of the contact force was realized by adjustment of displacement offset. The optimal motion curve can be converted into the cam profile. Simulation results show that the optimized cam profile can make the soft landing under high velocity, reduce the impact and vibration, achieve the fatigue life of 1.4×107 cycles.

Key words: mechanics, co-simulation and optimization, cam profile, mechanical dynamics, optimal control