Feedback time delay as a stabilizing tool in trajectory tracking, analysis and experiments

A trajectory-tracking problem is considered, represented by linear time invariant (LTI) dynamics of the error. Interesting complexity appears, both analytically and experimentally, when the feedback line is affected by a time delay. We analyze first, the influence of the delay on the system stability and then validate the findings via experiments and numerical simulations. In this effort the system dynamics and the control law are all kept fixed while the only varying parameter is taken to be the feedback time delay, /spl tau/. The analysis is conducted utilizing a recent framework of the authors, "cluster treatment of characteristic roots (CTCR)". We obtain the complete stability outlook of the system in the domain of /spl tau/ and observe an interesting property: the feedback delay may be utilized as a stabilizing tool within the control that is when properly selected it may improve the quality of control. We validate these observations via an experimental study and a dynamic simulation work. Ultimately, we propose a unique and interesting procedure to use the time delay as a stabilizing agent as well as a tool to enhance the control performance.