Control of vibrations for a parallel manipulator with flexible links — concepts and experimental results

13th International Conference on Motion and Vibration Control; 12th International Conference on Recent Advances in Structural Dynamics

Morlock, M.^1 ; Burkhardt, M.^2 ; Seifried, R.^1

Institute of Mechanics and Ocean Engineering, Hamburg University of Technology, Hamburg

21073, Germany^1

Institute of Engineering and Computational Mechanics, University of Stuttgart, Stuttgart

70569, Germany^2

关键词: Active vibration controls;    Comprehensive controls;    Control of vibrations;    End-effector trajectory;    Flexible multibody systems;    Linear quadratic regulator;    Parallel manipulators;    Proportional controller;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/744/1/012069/pdf
DOI  :  10.1088/1742-6596/744/1/012069

来源: IOP

【 摘 要 】

A comprehensive control approach is presented to reduce the vibrations of a parallel manipulator with a kinematic loop and two flexible links whereof the longer one can show significant oscillations. The control objectives are end-effector trajectory tracking and active vibration control. The system is modeled as a flexible multibody system and exact feedforward control based on the full dynamic flexible multibody system is applied to improve the end-effector trajectory tracking performance. Furthermore, the effect of different position control concepts for the two linear drives, such as gain scheduling for the utilized cascade control and a model based friction compensation, on the movers themselves as well as on the end-effector are discussed, which can be conflicting. Experimental results are presented illustrating the achievable accuracy of the end-effector tracking for different trajectories while showing significant error reductions for a feedforward control based on an elastic model in contrast to a rigid one. Finally, a model based curvature controller is utilized which actively controls the occurring oscillations of the parallel manipulator. Here, a proportional controller as well as a linear-quadratic regulator are applied and the impact of an additional curvature control on the end-effector tracking performance is investigated.