Multi-Axis Motion Controllers for Robots and AGVs

Abstract A micro computer based multi-axis motion controller for servo control of d.c. motors for robotic applications is presented in this paper. The motion controller interface uses LM628 precision motion controller chips. The design presented in this paper facilitates control of four motors from a single PC board consisting of four LM628 chips. The motion controller board has provisions to issue commands to all or some chips simultaneously. The presence of LM628 chips relieves the host computer of the responsibility of feedback control and it is free to perform other tasks once the necessary commands are downloaded to the motion controller board. The motion controller chips perform the closed loop control to drive the motors to the desired positions and/or to run at the desired velocity. The motion controller board also has safety features to stop the motors in case of problems and provide self diagnostics. This motion controller is used to control a prototype Automatic Guided Vehicle (AGV) and a five axis robot. The performance of the motion controller board is observed to be satisfactory.