Application of mode switching control using initial state variables in constraint final-state control to high-precision dual stage

Abstract

Precise positioning stages with high-speed and high-precision control performance are increasingly required for improving production efficiency and quality. In this paper, a final-state control method considering input limitation is applied to a novel high-precision dual stage during acceleration. In the method, the timing to activate the final-state control is automatically determined by a proposed criterion. The method can significantly reduce the calculation time so that realtime implementation becomes possible. Experimental results illustrate that the method can reduce the maximum thrust of the fine stage without degrading control performance.

Resonant-Dynamics LTV Feedforward for Flexible Motion Systems

“…The subsequent development of snap feedforward [5] made it possible to account for the compliant and potentially resonant dynamics expressed by non-rigid-body (NRB) modes. Examples in the LTI domain include [3] which deals with the feedforward control of a motion stage system in the discrete-time domain, and [2] which compares different model-inversion based feedforward control designs for nonminimum-phase systems. In [1] and [8], a combination of feedforward and feedback control synthesis is used to account for flexible dynamics.…”

A compliance feedforward scheme for a class of LTV motion systems

“…More recently, [8] addresses the problem of regulating the plant output when the disturbance is not known a priori, and [12] proposes a model-based non-causal feedforward scheme for double integrator-based Linear Time-Varying (LTV) systems, a class of systems also considered in the present work. In [6], work has been done on the discrete-time control of a stage, considering the plant as a Linear Time-Invariant (LTI) system. In [11] a feedforward method for flexible systems with time-varying performance locations is presented.…”