| 6-DOF parallel platforms have many characteristics, such as high load capacity, high stiffness, high accuracy, fast dynamic response and the small cumulative error, so 6-DOF parallel platforms are widely applied, such as flight simulator, new kind of machine-tool, and air space docking areas, and it should be further researched and developed in many applications, but the research about kinematics and force control strategy is also relatively deficient, these will impede the development of 6-DOF parallel platform in the future.The 6-DOF parallel robot was provided by Suzhou Boshi. Firstly, in order to get the movement of the branched-chain curves and athletic stance about platform, we apply matrix analysis and homogeneous coordinate transformation to establish a kinematic model for 6-DOF parallel platform.Secondly, through analysis the advantages and disadvantages of dynamics equation method, Newton-Euler method is used to establish the robot dynamic model, then the generalized force is calculated. The simulation results of 6-DOF parallel platform reveal the force of every branched-chain is reasonable.Then the thesis analyzed the force and position control theory of 6-DOF parallel platform, and in order to achieve the force/position cooperative control, the thesis used a Generalized Predictive Control (GPC) algorithm, and using multi-sensor fusion with force and position sensors to complete force/position synergic control. The control strategy can guarantee the tracking accuracy of the position and force and can make the end-effector move along the constraint surface with a desired contact force. The simulation results of 6-DOF parallel platform reveal the high accuracy of position and force tracking control, meanwhile the robot has a strong ability to adapt to uncertain environment.Then, the hardware of control system was introduced.Finally, the main research works are summarized and the problems required to further study are included. |
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