Extraction of External Torque Disturbance in Positioning Servomechanism

This paper presents the design of the digitallycontrolled positioning servomechanism whose steady state target position is unaffected by arbitrary class of load torque disturbances. For rejection of the torque disturbance effects on the steady state value of motor target angular position, the IMPACT (Internal Model Principle and Control Together) controlling structure is proposed. As an example, the servomechanism is considered in which the output drive torque is produced by using IFOS (Indirect Field Oriented Control) of an induction motor. Some improvements of the controlling structure are proposed in order to eliminate the ringing of control variable and thus to enable easier physical realization of the positioning servomechanism. The theoretical results are confirmed bysimulation.