Multi-criteria optimization of a hexapod machine. (English) Zbl 1146.70306

KÜbler, Lars; Henninger, Christoph; Eberhard, Peter

Multibody Syst. Dyn. 14, No. 3-4, 225-250 (2005).

Summary: Alternative designs of a hexapod machine are proposed and investigated with the aims to reduce flexibility and to eliminate singular kinematic configurations that appear in the workspace for the current design of the machine. The hexapod is modeled as a rigid multibody system. Articular coordinates associated with desired tool trajectories are computed by inverse kinematics. Hence, dynamic forces and torques are not considered and, as there is no closed-loop control realized in the model, the actual rotational and translational position of the tool deviates from the desired position due to machining loads. These deviations serve as objective functions during a multi-criteria optimization in order to determine the best design regarding stiffness/flexibility of the machine. Further, a general approach for evaluating flexibility behavior of the machine in the complete workspace is introduced and the results from the optimization are verified. Besides flexibility, a crucial point for machining tools is the size of the feasible workspace. Therefore, the influence of the design modification on the workspace is also taken into account.

MSC:

70B15	Kinematics of mechanisms and robots
90C29	Multi-objective and goal programming

Keywords:

dynamic system design; multi-criteria optimization; parallel kinematics; hexapod machine; singular configurations; flexibility analysis

Software:

Neweul; ADIFOR; NEWOPT/AIMS; HEXACT

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