Motion-force interaction in articulated-platform parallel mechanisms with closed-loop passive limbs

Mechanism and Machine Theory, vol. 228, pp. 106526

Abstract

Articulated mobile platforms and closed-loop passive limbs have become two prominent features in parallel robots for pick-and-place operations, enabling large rotation and efficient constraint, respectively. However, the influence of structural parameters inside closed-loop limbs on the performance of such mechanisms remains insufficiently understood. To address this issue, this paper proposes an evaluation approach for the motion-force interaction of articulated-platform parallel mechanisms with closed-loop passive limbs. The investigated mechanisms feature an 8-degree-of-freedom (DOF) articulated mobile platform constrained by eight wrenches from passive limbs, also referred to as an 8-wrench-8-DOF system. The power coefficient is adopted to quantify the relationship between each distal wrench and its corresponding virtual distal twist, as well as that between each proximal wrench and its corresponding actual proximal twist. Representative mechanisms, such as the Heli4 and H4 variants, are analyzed. The results show that the approach effectively reveals how closed-loop limb parameters influence the distal motion-force interaction performance of the parallel mechanism. The methodology offers a new perspective for evaluating articulated-platform parallel mechanisms and provides a theoretical foundation for future work, including dimension optimization and type selection.

Authors 3

1. Qizhi Meng corresponding Aachen Institute of Mechanism Theory

   RWTH Aachen University · University of Duisburg-Essen

   Affiliation as printed

   Chair for Mechanics and Robotics, Faculty of Engineering, University of Duisburg-Essen, Duisburg, 47057, Germany

   Institute of Mechanism Theory, Machine Dynamics and Robotics, RWTH Aachen University, Kackertstraße 16-18, Aachen, 52072, Germany

2. Burkhard J. Corves Aachen Institute of Mechanism Theory

   RWTH Aachen University

   Affiliation as printed

   Institute of Mechanism Theory, Machine Dynamics and Robotics, RWTH Aachen University, Kackertstraße 16-18, Aachen, 52072, Germany

3. Andrés Kecskeméthy

   University of Duisburg-Essen

   Affiliation as printed

   Chair for Mechanics and Robotics, Faculty of Engineering, University of Duisburg-Essen, Duisburg, 47057, Germany