Additive-state-decomposition-Based Event Triggered Spatial Repetitive Control for Fast Tool Servo Systems

This paper presents an event triggered spatial repetitive controller (ETSRC) method for a fast tool servo (FTS) system with multiple disturbances to improve the tracking performance for position-dependent periodic signals, which is based on the additive state decomposition (ASD) technique and the disturbance observer (DOB) approach. First, the original tracking problem for a position-dependent periodic reference input of the disturbed FTS system is decomposed into two sub-problems, namely, the tracking problem of the linear time-invariant (LTI) primary system and the robust stabilization problem of the secondary system. For the LTI primary system, an ETSRC method is constructed to ensure the tracking capability of the system while saving the communication and computational resources. Secondly, in the secondary system, the available position information of the FTS system is used to design a DOB to estimate and compensate for multiple disturbances. Finally, comparative simulations are performed on the FTS system and the results show that the method outperforms the conventional DOB control method and other repetitive control methods.