Research Of Key Technologies In The Control System Of Servo Press

With the continuous development of metal sheet forming research and application,equipment for material processing is improving towards flexibility and intelligence. Dueto its high flexibility and velocity variation ability, servo press is extensively adopted inthe field of sheet forming. However, the bottle necks of large scale high performanceservo pressbrake rest in high speed, high precision motion curves planning of heavy loadlarge inertia system and the capacity of large torque servo motor etc. Thus, this thesis doesits research systemically on the significant technologies for servo press controlling systemin three directions as follows: user-defining motion curve planning, multi-motorsynchronization control and controlling software design.Aiming at solving the problem of overswinging of the lower dead point in largeinertia system motion curves planning, a planning method is proposed based on cubicspline interpolation fitting. Compared to the conventional linear acceleration anddecelerations motion controlling method, this one can realize high controlling precision,motion transiting smoothly and motion impact reducing substantially. Experiment resultsshow that this algorithm is preferable to satisfy the demand for servo press to define itsmotion curve.Aiming at solving the problems of motor capacity limit and large dimensionworkstation unbalance loading in large-scale servo press, multi-motor synchronizationcontrol strategy is considered. Analyzing common methods of synchronization control,two valid ways are selected, that is master-follower control and electronics virtual masteraxis control. Results shows that the latter one has a higher synchronization controlprecision, the difference angle is within0.18°between two motors. Meanwhile,multi-motors synchronization measurement for unbalance loading is carried out. Subjectresults show that master motor adopting velocity control and follower motor adoptingtorque range limiting control can balance the loading among the motors.Aiming at security, stability and maintainability requirement for motor servo presscontrol software, four principles as integrity, observability, validity and transportability is proposed. According to the principles, state machine mechanism, parameter validityexamination is adopted in the design of servo press control software.The technology research mentioned above is applied successfully in servo pressbrakeof two specifications. A2000KN mechanical toggle rod servo press is applied on athermal forming production line in one state-owned enterprise. And1000KN synchronicdirect-drive servo press is developed as the experiment platform of state key laboratory ofmaterial forming and mold technology in Huazhong University of Science&Technology.