Kinematics and singularity analysis of a novel 7-DOF humanoid arm based on parallel manipulating spherical joints

The work addresses the motion characteristics and singularity of a novel 7-DOF humanoid arm based on parallel manipulating spherical joints. Firstly, according to parallel manipulating spherical joints, the arm is equipped with the better load bearing ability and better anthropomorphic characteristics than the traditional series configuration. Secondly, the complete forward kinematics is derived. Thirdly, the Jacobian matrix and the Jacobian matrix in the force field are obtained through differential transformation method, which is adopted for the singularity analysis in the later part. Finally, the calculation result of the dexterity provides clues for evaluating the manipulator.