CONTROLLER FOR AUTOMATIC MACHINE HAVING MAIN SHAFT

摘要

PROBLEM TO BE SOLVED: To provide a controller which speedily stops a main shaft without any overshoot. SOLUTION: A position command is sent periodically in a servo system from CNC 10 of the controller 1 of the automatic machine. The CPU of a digital servo circuit 12 reads position commands out of a common RAM 11 in specific cycles and calculates position deviation PER according to the position signal from a pulse coder. The product PG*PER of the position deviation PER and position PG is calculated and outputted to a speed command limiter. The speed command limiter limits the absolute value|VCMD|of a speed command VCMD outputted to a speed controller so that it does not exceed a speed command limit value VLIMIT (>0). The speed command limit value VLIMIT varies according to a specific transition pattern right after a main shaft fixed position stop command is outputted and decreases down to a final value WLMfin (>0) as the position deviation approaches 0.