Model Based Feedforward and State Control of the Parallel Kinematics PaLiDA

verfasst von

B. Denkena, H. Grendel, C. Holz

Abstract

In this paper, the development, testing and implementation of model based controls for a hexapod parallel kinematic machine is presented. First a rigid body model of the static and dynamic forces is designed and tested on a multibody simulation. The development of a model of the static and dynamic forces made possible a feedforward control of the rigid body model. The model is able to calculate all forces needed to hold and move the TCP (tool center point) correctly as was verified in simulation. Only inaccuracies and numerical deviation have to be considered by the position control of the struts. These effects lead to a higher tracking error in reality than in simulation. The feedforward control reduces the deviations by about two thirds, especially during the phases of acceleration. Further a model based state control has been developed for the linear direct drives. To avoid using the disturbed position signal for the differentiation of the actuator velocity a state observer is added. The reference action of the controlled loop and its disturbance performance has been increased by a feedforward control of the desired speed or a PI-control, respectively. This control concept clearly exceeds the former PID-controller in all aspects. The tracking errors are reduced significantly and the systems disturbance behavior is exceeded to allow further application of the PKM in production like handling or forces controlled processes.

Organisationseinheit(en)

Institut für Fertigungstechnik und Werkzeugmaschinen
Institut für Mechatronische Systeme

Typ

Aufsatz in Konferenzband

Seiten

185-202

Publikationsdatum

2004

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja