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Real-time trajectory tracking control of a parallel robot with flexible links
Publikationstyp
Journal Article
Date Issued
2021-04
Sprache
English
Author(s)
Institut
TORE-URI
Journal
Volume
158
Article Number
104220
Citation
Mechanism and Machine Theory (158): 104220 (2021-04)
Publisher DOI
Scopus ID
Real-time end-effector trajectory tracking is applied to a newly developed parallel robotic system with two highly flexible links. In contrast to previous works, which are typically based on offline precalculations or rigid model inversion, a dynamic flexible multibody model is inverted online. As the underactuated system is non-minimum phase, the inverse model needs to be rendered stable for real-time integration. Therefore, three approaches are developed for the considered robot. Firstly, output redefinition is applied by directly weighting the elastic deformations and rotations of the links. Secondly, a small counter weight is attached at an advantageous location on the robot having only a minor influence on the eigenfrequencies. Lastly, the rotational degree of freedom of the end-effector is used to stabilize the internal dynamics of the inverse model with a small motion of a rotary motor. The concepts and real-time applicability are validated within experiments which extends the related literature being highly based on theoretical investigations. The experimental end-effector tracking performance based on the three minimum phase approaches is close to the desired trajectory and clearly outperforms classical rigid body inversion.
Subjects
Flexible links
Internal dynamics
Model inversion
Parallel robot
Real-time control
Underactuated robot