Abstract: Position sensors for detecting the position of a linear motor relative to a platen are disclosed. In one embodiment, the sensor includes first and second magnetic members having teeth disposed relative to the teeth on the platen. A single turn planar drive winding is disposed around at least one of the teeth of the first and second magnetic members for producing a first and a second drive flux within each of the magnetic members. A single turn planar sense winding is disposed around at least one of the teeth of the first and second magnetic members for generating first and second outputs which are a periodic function of the position of the sensor relative to the platen. In another embodiment of the present invention, the sensor includes two magnetic members each having four pole pieces. A drive winding is disposed on each member for establishing first and second fluxes in each member which are symmetrical about a center of each member.

Abstract: Using as an actuator a stepper motor operated in a position-sensed closed loop mode via an electronic commutator by position and anomaly corrected motion control signals provided by a programmable logic array and by a microprocessor, provides a precision power positioner. The correct enabling of the motor coils, based on position sensing of the motor phase, using electronic commutation for the stepper motor, transforms the problem of enabling coil selection to the programmable logic array, which by its logic provides a simplified operating control as a function of present armature position feedback, and by a microprocessor corrects for anomalies such as temperature rise, square-law, and phase increase as a function of position desired and present armature position feedback signals, and thus provides high positional accuracy, high speed and force (torque) control independent of the motor cardinal step positions.