Patent ID: 8264669

Claim:
A movable body drive method in which a movable body is driven along a predetermined plane including a first axis and a second axis orthogonal to each other, the method comprising: a first process in which a position coordinate of the movable body is obtained, based on measurement values of three encoder heads among a plurality of first encoder heads whose position in a direction parallel to the second axis is different and a plurality of second encoder heads whose position in a direction parallel to the first axis is different, with the three encoder heads respectively facing three gratings among a pair of first gratings whose periodic direction is in a direction parallel to the first axis and a pair of second gratings whose periodic direction is in a direction parallel to the second axis that are arranged on a surface parallel to the predetermined plane of the movable body, the first gratings and the second gratings being positioned on a top surface of the movable body; and a second process in which a measurement value of an encoder head to be newly used is set so that the position coordinate is maintained before and after the switching of the encoder head.