METHOD FOR DETECTING INVERSION OF MOVING DIRECTION OF MOBILE OBJECT, AND SERVO CONTROL METHOD AND DEVICE USING THE METHOD

摘要

PROBLEM TO BE SOLVED: To accurately detect the direction inverting timing of a mobile object for correcting an error that is caused by the influence of a stick motion by detecting the inverting timing of one of both mobile objects at the current position of the other mobile object. SOLUTION: A numerical controller 2 analyzes a given NC program and outputs the center coordinates X0 and Y0 of a complete round to a friction corrector 7 of a servo controller 1. In a complete round motion, the moving direction of an X axis mobile object 5a is inverted when the position of a Y axis mobile object 5b is coincident with the Y coordinates of the center of the complete round. Then moving direction of the object 5b is inverted when the position of the object 5a is coincident with the X coordinates of the center of the complete round. The current positions Xt and Yt of objects 5a and 5b are always inputted to the corrector 7 from the position detectors 6a and 6b respectively. The correction value is calculated from the positions Xt and Yt and the inverted position information X0 and Y0 which are inputted from the controller 2 and then added to the velocity command value.