Nonlinear control for magnetic bearings in deployment test rigs: simulation and experimental results

Abstract

In this paper three control schemes for a test set-up of a magnetic bearing system for deployment rigs of solar arrays are described. The air gap of the magnet has to be controlled to a constant value independent of the deployment of the solar array. The deployment of the rig has been modeled as a variation in the load of the magnetic bearing. The considered controller design procedures are linear PD, nonlinear PD, and sliding mode. For all three schemes simulations are presented in order to make a comparison. However, the experiments with a test set-up have only been done for the linear PD and the sliding mode control scheme, since they were simple to implement. The results suggest to take the nonlinearities into account, since the nonlinear control schemes give better performance.

Development of an axial suspended AMB experimental bench for load and disturbance tests

“…A Butterworth filter is used, because it has a flat amplitude response in the pass-band and a steep cut-off response in the stop band (Pretorius, 1982). The Butterworth band pass filter is designed The equivalent damping constant (b eq ) and stiffness (k eq ) is thus (Scherpen, 1998): (16) The linearized AMB system with a PD controller can be represented by the block diagram in Figure 8. The parameters k a1 and k a2 are current to voltage gains, while the parameters k i1 and k i2 are the attraction force to current gains.…”

Nonlinear control of a magnetically levitated single-axis controlled axial blood pump

“…In [10], it applies state feedback controller with nonlinear control to control the magnetic-bearings system. In [11], the sliding mode control is used to control the magnetic-bearings system.…”

Design and Implementation of a Large-Scale Gravity Compensation System for Lunar Rover

“…The force unit is usually a soft spring connected in cable. The magnetic bearing is also used to reduce the friction between the trolley and the rail in [2]. The drawback of the passive GCS arises mainly from the inertia of the positioning unit.…”