电动螺旋压力机的打击能量与回程位置控制

Controlling strike energy and stroke position in an electrical screw press

研究了电动螺旋压力机的打击能量精确控制和滑块回程位置的准确定位问题.采用直接转矩控制实现稳定的电动机转矩输出,采用速度模式与转矩模式互相切换的方法保证打击能量的稳定,消除了滑块惯性下滑时因摩擦和直流励磁引起的能量损失,并避免了因急剧正反转易引起的电动机过流现象,能量相对误差可控制在2%以内;利用电机自身制动力实现滑块减速,采用基于预估控制系统的速度规划算法解决电机制动力难以保证大惯量负载条件下滑块的准确定位问题,滑块回程位置误差限定在±1 mm以内.

Exact strike energy and precise backward position control of the slide for an electrical screw press were researched. Direct torque control of speed regulation technology was adopted to output the steady torques of the motors. In order to keep strike energy, the method alternating between speed mode and torque mode is applied to resolve the energy dissipation which is aroused by mechanical friction and DC magnetization when the slide is in a coast move, and to avoid the phenomenon of overcurrent which always occurs when the motor reverses sharply. Thus, the stroke energy tolerance is guaranteed below 2%. The slowdown of the slide is achieved by the motors＇ own brake power, but the precise backward stroke position cannot be easily mastered because of the shortage of this kind of brake power. However, a speed of layout method based on a predictive control system has been designed. The backward stroke position error of the slide is eventually kept within ±1 mm.