Control for automatic machine tool drive.

摘要

A drive (32) system includes a single stage gear reducer end power screw (32), a brushless variable-speed electric motor (12) with position and velocity sensing instrumentation, a solid state power amplifier, and a programmable controller. During operation an absolute positional reference is established when the slide actuates a non-contacting limit switch to signal that the slide is within less than one motor revolution of the correct starting point. A memory accessible by a microprocessor has paired values of velocity and position stored in a table representing ideal such values for deceleration portions of the motion cycle. Alternatively, the microprocessor computes each new value of position and velocity in real time as required to update the velocity commands sent to a comparator. The comparator compares the predetermined slide position to the actual slide position and signals the microprocessor that a change in output to the motor power supply is required. A digital to analog converter converts the motor velocity signal that issues from the microprocessor to a variable d.c. voltage whose magnitude varies over a range that determines the sense of direction and speed of the drive motor.