METHOD OF SUPPRESSING TORSIONAL VIBRATION IN A MOTOR SPEED CONTROL SYSTEM AND APPARATUS THEREFOR

摘要

A method of suppressing torsional vibration in a motor speed control system having a mechanism which transmits the drive torque from the motor to the load via a drive shaft which has a torsional spring system, and an apparatus therefor. Signals of a motor speed detector usually contain pulsating signals of a high frequency, but differentiation of the speed detection signals does not provide signals that vary in proportion to the rate of change of the motor speed. However, pulsating value of speed signals can be decreased if an average value of signals of the motor speed detector (3) is calculated for every predetermined period, and the ratio of change of the motor speed can be calculated from the above signals. In this invention, the acceleration torque instruction of the motor is given by an output signal of a speed controller (11), and the load torque of the motor that is a disturbance to the acceleration torque of the motor is controlled in a direction to be cancelled by the torque instruction compensation signals output by a motor acceleration torque controller (25) that has a proportional gain and an integrator. This acts in a direction to cancel the disturbance torque of the motor caused by acceleration, sudden change in the load or distorsion of the drive shaft, and whereby torsional vibration is suppressed and variable speed characteristics are obtained maintaining stability. IMAGE