Design and implementation of position feedback controllers for an X-Y table

A circuit was designed for feedback modification of a computer controlled stepping motor positioning system. Instrumentation amplifiers were used to obtain the motor phase currents. The sum of the amplifier outputs was applied to an analog-to-digital converter. The converter data was multiplexed to a computer's parallel port inputs. Experiments were performed to find the correspondence between torque, current, and the converter output. A number of C language programs were written to modify the stepping of the motor in reaction to high torque.<>