Design and Control Analysis of 2-DOF Spherical Wrist

In this paper, a novel design of a 2-DOF spherical wrist which is based on umbrella gear transmission is proposed. Using three umbrella gear and their attribute, a 2-DOF spherical wrist is designed to have the capability to pitch move when bilateral umbrella gear homodromous rotation and swing move when bilateral umbrella gear inversus rotation. This spherical wrist has two degree of freedom which can pitch and swing. Through constructive solid geometry, the spherical wrist's motion space is analyzed. Moreover, through the gear transmission relationship, the relation between the spherical wrist's angular velocity and the electromotor's angular speed is established. Using the software of Solidworks Motion to verify motion characteristics and Matlab to analyze experimental data and achieve experimental results. The experimental results show that the 2-DOF spherical wrist has large range of movement and high integration. Moreover, it's convenient to control the wrist.