Configuration Synthesis And Performance Study Of Humanoid Joint Based On Parallel Mechanism

Humanoid robot is one of the most active branches of robotics,joints are keys of function realization.In this paper,humanoid ankle and shoulder are taken as object,spherical parallel mechanism with few DOFs are taken as prototype,configuration synthesis and performance analysis are conducted according to bionic principle.The main contents are as follows:According to the principle of motion bionics,spherical parallel mechanism with 2-DOFs UP+R is chosen as prototype,and UP+R ankle mechanism is obtained,statics and stiffness of this ankle mechanism are analyzed.On the basis of UP+R ankle mechanism,the anthropomorphic spherical parallel humanoid ankle mechanism with the characteristic of mechanical unloading and balanced stiffness is obtained according to the theory of bionic design.Kinematics,statics and static stiffness analysis of ankle mechanism are all conducted.Finally,the prototype of ankle is manufactured and extreme position angle is measured.A group of passive spherical hinges with large workspace are designed to imitate ball and socket joints,3-RRR spherical parallel mechanism with 3-DOFs is introduced to imitate parallel drive of muscle groups,the design idea of bias output is adopted to increase the workspace,and then the universal ball and socket mechanism is obtained.This mechanism is taken as prototype,and then the spherical parallel humanoid shoulder is designed according to the principle of structural bionic design and spatial consistency,and the workspace of shoulder is analyzed.Finally,the prototype of shoulder is manufactured and the continuity of workspace is verified.The movement of human shoulder girdle is measured,and the experimental data is obtained to describe the movement of human shoulder girdle.From the view of motion bionics,2PUS+RR rotational parallel mechanism with 2-DOFs is proposed to be taken as prototype of humanoid shoulder girdle,bionic design of mechanism parameters is conducted according to the motion data of human shoulder girdle.Two spherical parallel mechanisms with 2-DOFs are proposed to be taken as prototype of humanoid shoulder girdle for simple structure and conventional control.Inverse kinematics solution of this two mechanisms are obtained.2PUS+U spherical parallel humanoid shoulder girdle mechanism and RPRS+U spherical parallel humanoid shoulder girdle mechanism are obtained.The motion of human shoulder girdle is considered,(2PUS+U)-(3RRR)and(RPRS+U)-(3RRR)two double-spherical hybrid humanoid shoulders are obtained.The mapping relationship of workspace between double-spherical hybrid humanoid shoulder and human shoulder is derived.Kinematics model of the positive solution of doublespherical hybrid mechanism is established.The inverse solutions of two double-spherical hybrid humanoid shoulders are derived,and the accuracy verified by simulation test.