Experimental studies of control concepts for a parallel manipulator with flexible links

다국어 초록 (Multilingual Abstract)

Control of flexible multibody systems, such as flexible manipulators, is a challenging task. This is especially true if end-effector trajectorytracking is aspired. On the one hand, these systems require a large number of generalized coordinates to describe their dynamicalbehavior accurately. On the other hand, only a small subset of these values can be measured or reconstructed on-the-fly. Hence, it is difficult,if not nearly impossible, to use a state controller. In addition, flexible systems are underactuated, i.e. they possess less control inputsthan generalized coordinates. In case of a non-collocated output controller, which is the case for end-effector trajectory tracking, theclosed loop of the system might lose passivity and is non-minimum phase. In order to achieve end-effector trajectory tracking, exact andapproximate feed-forward controls can be applied. In this work, two different versions of such concepts are compared experimentally.

These model-based concepts are computed off-line and they supply, next to the required input values, a C1-continuous solution of thecomplete state vector which can be used for feedback control. If the system is non-minimum phase, a two-sided boundary value problemhas to be solved and the solution includes a pre-actuation as well as a post-actuation phase. While the exact method incorporates all dynamicaleffects of the flexible multibody system, the approximate concepts neglect certain implications, for example the dynamical effectsdue to the flexibility. In addition to the presentation of the theoretical basics of the control approaches and the underlying models,this contribution addresses some of the crucial obstacles, which have to be overcome for the operation of the test bench, e.g., signal conditioning,state reconstruction and friction compensation. Since the installed sensors do not allow the direct measurement of the endeffectorposition, image tracking is used to judge the quality of the different control approaches.

참고문헌 (Reference)

1 M. W. Spong, "Robot modeling and control" John Wiley & Sons 2006

2 C. J. Damaren, "Passivity and noncollocation in the control of flexible multibody systems" 122 (122): 11-17, 2000

3 R. Seifried, "Multibody Dynamics:Computational Methods and Applications, Computational Methods in Applied Sciences 28" Springer 53-75, 2013

4 "Modbus: Modbus application protocol application V1.1b3"

5 M. S. Grewal, "Kalman filtering: theory and practice using MATLAB" John Wiley & Sons 2011

6 M. Burkhardt, "Inversion based trajectory tracking control for a parallel kinematic manipulator with flexible links" 2013

7 T. Kurz, "From Neweul to Neweul-M2: symbolical equations of motion for multibody system analysis and synthesis" 24 (24): 25-41, 2010

8 B. Bona, "Friction compensation in robotics: an overview" 4360-4367, 2005

9 A. Ast, "Flatness-based control of parallel kinematics using multibody systems – simulation and experimental results" 76 (76): 181-197, 2006

10 R. A. Singer, "Estimating optimal tracking filter performance for manned maneuvering" Target Hughes Aircraft Company 1970

11 R. Seifried, "Dynamics of underactuated multibody systems" Springer 2014

12 J. Blanchette, "C++ GUI Programming with Qt4" Prentice Hall 2008

13 X. R. Li, "A survey of maneuvering target tracking: dynamic models" 212-235, 2000

14 W. Blajer, "A geometric approach to solving problems of control constraints: theory and a DAE framework" 11 (11): 343-364, 2004