Kinematics Analysis of Serial-Parallel Hybrid Humanoid Robot in Reaching Movement

As the demand to the practical operation ability of humanoid robots improving, serial-parallel hybrid structure has started to be used in the research of humanoid robot. However, analytical solutions of the forward and inverse kinematics are hard to obtain due to the redundancy of humanoid robot and the complex topology of hybrid structure. Besides, humanoid robots should have the capability to complete complicated operation in the low structured task workspace. So, it should have not only the humanoid shape but also the behavior that adapts to the direct interaction with people. In this work, a novel 4-DOF hybrid humanoid robot was taken as an example, the forward kinematics equation was derived, the theory of screws and lie group and lie algebra were applied to calculate the end velocity. A numerical calculation method based on neurophysiology sensorimotor transformation model and fuzzy logic compensator was proposed to solve the inverse kinematics in reaching movement. The proposed strategy can make the robot execute reaching movements with human-like posture. Simulation and test results validate the effectiveness respectively.