High order disturbance observer design for linear and nonlinear systems

© 2015 IEEE. In this paper, a disturbance observer is proposed for nonlinear systems with high order disturbance, where not only disturbance but also its high order derivatives are estimated. The relationship of the proposed observer with the existing results is discussed. Then, the result is further extended to the case of minimal-order output-based disturbance observer design for linear systems subject to high order disturbances. Two practical examples about actuator fault diagnosis for a nonlinear missile system and disturbance estimation for a double-effect pilot plant evaporator system with unobservable states are provided to illustrate the effectiveness of the proposed approaches

CONTROL GLOBAL PD PARA SEGUIMIENTO DE POSICIÓN EN MOTORES A PASOS DE IMANES PERMANENTES

El control del motor a pasos de imanes permanentes es un tema de bastante interés en la actualidad ya que es bastante utilizado en aplicaciones que requieren precisión y por que puede ser controlado a lazo abierto. Pero en algunas aplicaciones el desempeño del motor a lazo abierto no es suficiente, lo que ha motivado al diseño de controladores a lazo cerrado que consideren la dinámica no lineal completa del motor. En este artículo se presenta el diseño de un controlador para el seguimiento de posición en motores a pasos de imanes permanentes que acciona una carga dependiente de la posición, además se prueba la estabilidad global del sistema a lazo cerrado utilizando el método directo de Lyapunov y se presentan resultados en simulación del controlador.Palabra(s) Clave(s): estabilidad de Lyapunov, imanes permanentes, motor a pasos, seguimiento de posición

Compensative microstepping based position control with passive nonlinear adaptive observer for permanent magnet stepper motors

This paper presents a compensative microstepping based position control with passive nonlinear adaptive observer for permanent magnet stepper motor. Due to the resistance uncertainties, a position error exists in the steady-state, and a ripple of position error appears during operation. The compensative microstepping is proposed to remedy this problem. The nonlinear controller guarantees the desired currents. The passive nonlinear adaptive observer is designed to estimate the phase resistances and the velocity. The closed-loop stability is proven using input to state stability. Simulation results show that the position error in the steady-state is removed by the proposed method if the persistent excitation conditions are satisfied. Furthermore, the position ripple is reduced, and the Lissajou curve of the phase currents is a circle