Kinematic Analysis of an Omnidirectional Mobile Assembly Robot

For the special assembly application in narrow space with uneven ground, a 5-DOF (degree of freedom) omnidirectional mobile assembly robot is developed. It is composed of an omnidirectional mobile platform with four groups of parallel MY (mutual YoYo) wheels and a 2-DOF parallel lifting mechanism. Firstly, the overall kinematic model of the robot is built based on both omnidirectional movement of the robot and the structural features of the 2-DOF parallel lifting mechanism. The circular curve trajectory of the robot is simulated based on the model. Then, the hyperbolic filtering PD (proportional derivative) controller is used to track the trajectory of the robot and analyze trajectory tracking errors. The controller can control average error at about 5 mm, and the errors decrease as the tracking time decrease. Finally, the experiment results validate the accuracy of the kinematic model and the simulation results, and the controller can realize the trajectory tracking quickly and accurately. It further verifies the superiority of the omnidirectional mobile assembly robot.