Enhancing transient response of asymptotic regulation with disturbance onset

In incorporating an internal model (IM) to an linear time invariant (LTI) feedback system to achieve asymptotic regulation for exogenous disturbances, limitation in robust stability often hinders the transient response performance, such as the convergence rate and maximum output magnitude, of the LTI closed loop system. When the onset time of the disturbance introduced to the system is known, we formulate a linear time varying (LTV) controller, which exploits this information to improve the transient performance while maintaining the asymptotic regulation and desired robust stability. Simulation and experimental results for asymptotic regulation of a linear motor are presented to demonstrate the improvement of the proposed LTV over LTI controller.