| 摘要 |
PROBLEM TO BE SOLVED: To prevent a drive motor for driving a rotary table from being an overload state or overheated by influence of a processing load.SOLUTION: A rotary table is rotated by a processing load. A drive motor increases output torque to return the rotary table to a target position positioned. When the output torque reaches an upper limit torque Tmax, or when the output torque equal to an allowable torque Tp or greater continues for a predetermined time &Dgr;T, reduction of the output torque is prompted by changing the target position commanded to the drive motor. Thus, an overload state and overheating of the drive motor is prevented. When the output torque becomes less than the allowable torque Tp, the target position is changed to make a positional deviation of the drive motor become zero, and the positional displacement is quickly reset. Thus, processing error is reduced and processing accuracy is improved. |
