Improving the Position and Vibration Control of Multi-Body Structures Under External Disturbances

An H infinity based controller has been developed for an experimental multi-body test structure to reduce vibration in the flexible beam components, while maintaining accurate position control of the rigid components. The controller was effective at attenuating vibration in the flexible beam when it lifts off of a rubber end stop. However, it was not as effective in attenuating vibration caused by external loadings, or due to contact with the end stop. This paper dem-onstrates the effects of changes to the weighting functions associated with the controller design under these conditions. Although changes to the weighting functions can result in greater damp-ing of the flexible components, this could result in less accurate position control of the rigid components.