Motion Control And Stability Study Of Mobile Parallel Robot

Mobile robotics technology is one of the most popular technologies in recent years. As multifunctional moving carrier, this type of robot is widely used in various fields. However, its arms are usually serial mechanisms, hence their rigidity is small. As an important branch of robotics research area, parallel robot has many advantages, such as higher structural rigidity, higher load capacity, higher position accuracy and so on. It has been widely used in analog equipment, such as CNC machine, sorting institutions, micro-manipulator and measuring machines and so on.The disadvantages of these two classes of robots limit their applications. Mobile Parallel Robots(MPR) are a class of robots which integrate the structural features of both parallel robots and mobile robots. The major merits of MPR include the manipulation flexibility, big workspace, high rigidity, good load-bearing capacity, flexible posture-variation and convenient avoiding obstacles capability. It can also realize adaptive adjustments to the targeted position and the orientation according to the task requirements.In this thesis a 6-DOF MPR composed of a moving platform and 3 PPUU subchains with the omnidirectional wheels is investigated. This paper is organized as follows: First, the mechanism of MPR is analyzed. Based on the kinematics, the control of MPR's moving platform is studied and then an adaptive control method with constant-orientation is studied. Second, the stability of MPR is analyzed, including static stability and dynamic stability. In order to improve the stability and flexibility, a method of structural optimization is introduced. Finally, the experiments are performed to verify the theoretical analysis.This work has completed a study of motion control, stability and structure optimization of MPR, and the results obtained from this study provide the foundation for further studies and practicability of MPR.