Patent ID: 6741055
Filing Date: 2004-05-25
Classification: G05B

Abstract:
A positioning-controlling apparatus comprising:a servo motor; a servo driver for controlling an operation of said servo motor; a rotary encoder for detecting an amount of rotation of said servo motor; a moving mechanism driven by said servo motor so as to move an object; a linear encoder for detecting an amount of movement of said moving mechanism; and an origin sensor for detecting whether the object to be moved by said moving mechanism is located within a detectable region; wherein said servo driver is operable to: detect a commutation signal phase, from said rotary encoder, for driving said servo motor; generate an electrical current instruction with rectangular waveform pulses based on the commutation signal phase from said rotary encoder until said rotary encoder detects a Z phase or until said linear encoder detects a Z phase; after said rotary encoder detects the Z phase or said linear encoder detects the Z phase, generate an electrical current instruction with sine waveform pulses based on the detected Z phase, thereby switching a driving mode of said servo motor from rectangular waveform pulses to sine waveform pulses; at a beginning or resumption of operation, control said servo motor so that said moving mechanism returns the object to an origin position corresponding to a position of the Z phase detected by said linear encoder; and after the object is moved to the origin position, control said servo motor so that said moving mechanism moves the object to a required position and keeps the object at the required position; and wherein, while said servo driver is controlling said servo motor so that said moving mechanism is returning the object to the origin position, and when said origin sensor first detects that the object is located within the detectable region, said linear encoder is operable to detect the Z phase only after said rotary encoder detects the Z phase.