Integrated precision 3-DOF position sensor for planar linear motors

Planar linear motors have been shown to be capable of fast accurate 2-DOF motions, making them useful for assembly tasks. However, the lack of sensing capability has limited their applications. Previous planar motor sensors were precise but bulky and sensed only a single direction of motion. We present a small integrated 3-DOF sensor capable of 0.2 /spl mu/m position resolution (1/spl sigma/) which has been integrated with an existing planar linear motor without changing its overall size. Physical design of the sensor is presented as well as the custom electronics used to produce a low-noise DC output from the small signal levels of the sensor. Finally, we present results that demonstrate the resolution and accuracy of the complete sensor system.