偏置输出的3-RRR+(S-P)仿生关节机构设计与分析

针对3-RRR+(S-P)球面并联机构安全工作空间较小,不能满足人形机器人肩关节、髋关节工作空间设计需求的问题,依据仿生设计理论,参照人体肱骨结构,提出了偏置输出的设计思想,并以3-RRR+(S-P)球面并联机构为原型,设计完成了偏置输出的3-RRR+(S-P)仿生关节机构。通过坐标变换的方法,得到新型仿生关节机构与原型机构工作空间的映射关系,进而得到新型仿生关节机构的安全工作空间。在保留原型机构运动学、力学特性的基础上,新型仿生关节机构的安全工作空间大幅增大,完全可以满足人形机器人肩关节、髋关节工作空间的设计需求。

Structure Design and Workspace Analysis of 3-RRR+(S-P) Bionic Joint Mechanism with Offset Output

The 3-RRR+(S-P) spherical parallel mechanism is very similar to human shoulder and hip joint. This mechanism can be taken as the prototype of the shoulder and hip joint for humanoid robot. However, the secure workspace of 3-RRR+(S-P) spherical parallel mechanism is so small, that could not meet the requirements of the shoulder and hip joint for humanoid robot. According to bionics and structure of human thighbone, the design idea of biasing output was proposed. And then, the 3-RRR+(S-P) bionic joint mechanism with biasing output was proposed based on the 3-RRR+(S-P) spherical parallel mechanism. For the bionic joint mechanism and prototype mechanism, there was a certain mapping relation between their secure workspaces. The mapping relation was obtained based on conversion of coordinates, and then, the secure workspace of the proposed bionic joint mechanism was obtained. The 3-RRR+(S-P) bionic joint mechanism with biasing output retained the kinematic and mechanical performance of prototype mechanism, and had a substantially increased secure workspace. The secure workspace of the proposed bionic joint mechanism could meet the requirements of the shoulder and hip joint for humanoid robot absolutely.