Patent ID: 6603562
Filing Date: 2003-08-05
Classification: G01B,G03F,G05B,H02K

Abstract:
A two-dimensional positioning apparatus for positioning an object in a two dimensional direction, said apparatus comprising:a platen comprising teeth formed at fixed spacings along X and Y axes; a slider comprising two X-axis motors, two X-axis position sensors, a Y-axis motor, and a Y-axis position sensor, said slider being loaded with said object and disposed above said platen; a converter for producing signals for detecting X-axis position of a center point of said slider and a yaw angle &thgr; of said slider according to position detector signals from said two X-axis position sensors; an X&thgr; controller for feedback controlling movement of said slider in X-axis and &thgr;-axis directions separately according to signals converted by said converter; a command converter circuit for converting control output of said controller to propulsion commands to be supplied to said two X-axis motors, said command converter circuit comprising: means for receiving X-axis and &thgr;-axis propulsion commands outputted by said controller and for producing propulsion commands to be supplied to said two X-axis motors according to a sum of and a difference between said X-axis and &thgr;-axis propulsion commands, and means for restricting X-axis limits of said propulsion commands Ir0 to Imaxâˆ’|Ir&thgr;|, wherein Imax is the maximum value of the propulsion commands and Ir&thgr; is a &thgr;-axis propulsion command; and a Y-axis controller for receiving a position detection signal from said Y-axis position sensor, and for feedback controlling Y-axis direction according to said position detection signal.