IEEE Transactions on Automatic Control, Vol.65, No.3, 1333-1339, 2020
Integral Control of Stable Negative-Imaginary Systems Preceded by Hysteresis Nonlinearity
In this note, constant reference tracking using integral control for negative-imaginary (NI) systems preceded by hysteresis nonlinearity is addressed. The hysteresis nonlinearity is considered to be slope-restricted, though no specific modeling framework is exploited. It is effectively shown that integral tracking controllers are guaranteed to exist when a stable NI system with sign-definite dc-gain is preceded by such hysteresis nonlinearities. When the dc-gain is negative-definite, under positive feedback configuration with positive slope-restricted hysteresis, it is established that the integral controller gain can be any positive diagonal matrix. The development of the proposed model-independent inversion-free scheme is carried out in general state-space setting and is applicable for multiple-input multiple-output systems with decoupled hysteresis nonlinearities. Effectiveness of the results is illustrated with examples.
Keywords:Hysteresis;Linear systems;Stability analysis;Aerospace electronics;Control systems;Dynamics;Electron tubes;Hysteresis nonlinearity;integral control;negative-imaginary (NI) system;piezoelectric actuator;reference tracking