LQG control of elastic servomechanisms based on motor position measurements

The control of the load position in an elastic servo positioning system is addressed. Compliant with a design constraint common in industrial robotics and the machine tool industry, this study assumes that the motor position only is measured. LQG methods are used to observe and feedback the whole state of the system. Particular attention is devoted to some practical issues such as the role and tuning of an integral action and of feedforward filters for setpoint tracking, and the choice of the weights for LQ design. Experimental comparison to state of the art PID design is discussed.