Velocity control of servo systems using an integral retarded algorithm

•A novel delay-based controller called the Integral Retarded controller is introduced.•Analytic calculation of the algebraic design rule is presented.•Experimental results demonstrate that delays can reduce control effort.

This paper presents a design technique for the delay-based controller called Integral Retarded (IR), and its applications to velocity control of servo systems. Using spectral analysis, the technique yields a tuning strategy for the IR by assigning a triple real dominant root for the closed-loop system. This result ultimately guarantees a desired exponential decay rate σd while achieving the IR tuning as explicit function of σd and system parameters. The intentional introduction of delay allows using noisy velocity measurements without additional filtering. The structure of the controller is also able to avoid velocity measurements by using instead position information. The IR is compared to a classical PI, both tested in a laboratory prototype.