A Motion Control of Multi-layer Retractable Roof Using a Non-linear Disturbance Observer

This paper presents a motion control scheme for a multi-layer slide roof using non-linear disturbance torque observer to reduce the mechanical vibration and speed fluctuations. In the multi-layer retractable roof system, weight and load fluctuations can suddenly occur when the roof layers are overlapping. This leads to speed ripples, high mechanical vibration, and a reduced motion control performance. In this paper, a non-linear disturbance observer is proposed to improve the motion control performance. The disturbance torque is estimated and then added to the torque current reference of the speed controller to compensate the sudden load fluctuation as the roof layers are moving. To increase the stability of the observer, torque dead-zone is used at the starting area to reduce mechanical vibration. In the designed instantaneous position and speed reference adaptive control scheme, the speed reference of the slide roof is determined based on the motion pattern and instantaneous position error. In addition, the proposed disturbance observer can counter the sudden load change which results in reduced position error and lower speed fluctuation. To verify the proposed idea, a 2-layer slide roof prototype was manufactured and experiments were performed. The proposed control scheme shows the advanced motion control performance with reduced speed fluctuation and vibration.