A Control System for Dual-Axis Linear Motor

Fundamental positioning characteristics of a dual-axis Sawyer linear motor are described. The Sawyer motor is capable of high positional accuracy. An electronic control unit of the motor whose velocity is proportional to the frequency of the electric current was produced in our laboratory. The positioning system was constructed using two Sawyer motors, an air bearings suspension unit and an electronic control unit. The stable motion of the motor was confirmed on the open loop operation. The adjustable operating conditions were the live load of 1㎏, the maximum acceleration of 1.2G and the maximum velocity of 350㎜/s. Absolute positioning accuracy was improved within ±5㎛, on microstep operating conditions of dividing one pitch of 508㎛ into 508 steps. The following two conclusions were obtained. An accelerating-cruising-decelerating control is effective for reduction in the travel time required. Also, microstep operation is effective for improving the resolution of position.