Data-driven Ripple-free Control for Unstable Dual-rate Systems

A dual-rate sampled-data control system is designed in which the sampling period of a process output is longer than the holding period of a process input. In such a system, there are the process output may still oscillate even when the sampled output converges to a reference input. Therefore, the intersample ripples caused by the input oscillation must be suppressed. For known dynamic systems, it is possible to design the output to follow the reference input while suppressing input oscillations in steady state, but this is not easy when the dynamic characteristics are unknown. For a control system with unknown dynamics, a dual-rate control law is extended using the step response of the control system to suppress the output oscillation between the sampling period.