Abstract
In servo systems, it is known empirically that stability margin at the error channel influences the characteristics of the response against reference command. This paper, therefore, presents a method of designing servo system, which has a certain specified stability margin at the output of servo compensator or the error channel.
The relation between the stability margin at the input of plant and the one at the output of servo compensator is derived, where the state feedback law for the augmented system of plant and servo compensator is determined using the solution of a generalized Riccati equation. The stability margin at the output of servo compensator can be specified by means of this relation and an adjusting parameter for the state feedback gain, and design guidance is proposed for improving the behavior of the response for command input. It is also shown that the servo system possessing integrity at the error channel or robust stability against saturation of integrator can be designed using the conventional Riccati equation for the augmented system.
