A robust servo control unit for robotic manipulators is developed, using a permanent magnet DC motor driven by a 4-quadrant transistor chopper. Its major feature is that it can be used either as a torque-type servo for the dynamic control of robotic manipulators or as a conventional velocity-type servo for NC machine tools.
The 'Hysteresis-Controlled Bang-Bang Control' method is adopted for the armature current control while the PI control method is employed for the velocity control. The Unit, as a torque-type servo, constitutes an essential building block when implementing almost all kinds of position control algorithms for robotic manipulators such as the ($α_-$) computed torque algorithm, the resolved acceleration algorithm, the adaptive algorithm, the VSS algorithm as well as the PID algorithm.