Tree-type hybrid mechanism configuration synthesis based on modular decomposition and power-concentrated joint closed-loop design

Abstract

Mechanisms with multiple end-effectors are widely used in engineering due to their ability to synchronize and collaborate on multiple processes. However, this kind of mechanism is difficult to design due to its high topological complexity and complex applied loads. In order to solve this problem, this article proposes a configuration synthesis method for tree-type hybrid mechanisms from two aspects: modular decomposition of open-loop mechanisms and closed-loop design of power-concentrated joints. According to the correlation of the space of degrees of freedom between the end-effector, the mechanism is decomposed into different modules for hierarchical design to simplify the mechanism structure. The unit power concentration index is utilized to find the joints where the power output is relatively concentrated and replace them with low-complexity single-degree-of-freedom closed-loop structures to improve the structural stiffness and dynamic performance of the mechanism. Finally, the feasibility of the proposed method is verified by taking a steel arch looping mechanism with four end-effectors as an example. The aim of this article is to design a simple and reliable multi-branch mechanism with high load carrying capacity to make it more adaptable to the complex and harsh operating environment, which can provide a reference for the design of similar engineering equipment.