L1 Adaptive Control for a Vertical Rotor Orientation System

Abstract

Bottom-fixed vertical rotating devices are widely used in industrial and civilian fields. The free upside of the rotor will cause vibration and lead to noise and damage during operation. Meanwhile, parameter uncertainties, nonlinearities and external disturbances will further deteriorate the performance of the rotor. Therefore, in this paper, we present a rotor orientation control system based on an active magnetic bearing with L 1 adaptive control to restrain the influence of the nonlinearity and uncertainty and reduce the vibration amplitude of the vertical rotor. The boundedness and stability of the adaptive system are analyzed via a theoretical derivation. The impact of the adaptive gain is discussed through simulation. An experimental rig based on dSPACE is designed to test the validity of the rotor orientation system. The experimental results show that the relative vibration amplitude of the rotor using the L 1 adaptive controller will be reduced to ∼50% of that in the initial state, which is a 10% greater reduction than can be achieved with the nonadaptive controller. The control approach in this paper is of some significance to solve the orientation control problem in a low-speed vertical rotor with uncertainties and nonlinearities.

Nonlinear Control of a Vertical Rotor Orientation System

“…(1) that the bottom-fixed rotor can be described as a 5-order differential equation. In the authors' previous work [9,10] , as the angular displacements, i.e. α and β, does not influence the rotation speed dynamic, the state equation of x 5 is omitted and ω c is treated as a constant.…”

“…(1) will reduce to a 4-order differential equation, as shown in Equ. (2) in [10]. This treatment is acceptable when the rotational speed is high enough (i.e.…”