Efficient implementation of patched LQR for control and protection of multi-mass drives

Multi-mass drives are in principle low-damped oscillatory systems. Controllers for such systems must be designed with care, especially when safety constraints or equipment constraints need to be respected during their operation. Recently a robust protective control technique based on invariant sets was introduced and experimentally verified for such applications. The idea is to correct the control input to the drive as to avoid the multi-mass drive constraints violation in the future. In this paper we merge Linear Quadratic Regulator (LQR) with the correction procedure and exploit convexity of the raised control problem to significantly reduce the required on-line computational power and memory requirements and to broaden the applicability of the control scheme to multi-input systems.