P-FABRIK: A General Intuitive and Robust Inverse Kinematics Method for Parallel Mechanisms Using FABRIK Approach

TL;DR

P-FABRIK is a versatile and robust inverse kinematics method for parallel mechanisms, leveraging a novel decomposition strategy and FABRIK algorithm to handle diverse configurations and out-of-workspace targets efficiently.

Contribution

It introduces a general inverse kinematics approach for parallel mechanisms using topological decomposition and FABRIK, addressing limitations of traditional methods.

Findings

Demonstrated effectiveness across various parallel mechanisms.

Verified robustness with out-of-workspace targets.

Showed computational efficiency through simulations.

Abstract

Traditional geometric inverse kinematics methods for parallel mechanisms rely on specific spatial geometry constraints. However, their application to redundant parallel mechanisms is challenged due to the increased constraint complexity. Moreover, it will output no solutions and cause unpredictable control problems when the target pose lies outside its workspace. To tackle these challenging issues, this work proposes P-FABRIK, a general, intuitive, and robust inverse kinematics method to find one feasible solution for diverse parallel mechanisms based on the FABRIK algorithm. By decomposing the general parallel mechanism into multiple serial sub-chains using a new topological decomposition strategy, the end targets of each sub-chain can be subsequently revised to calculate the inverse kinematics solutions iteratively. Multiple case studies involving planar, standard, and redundant parallel mechanisms demonstrated the proposed method's generality across diverse parallel mechanisms. Furthermore, numerical simulation studies verified its efficacy and computational efficiency, as well as its robustness ability to handle out-of-workspace targets.