Research On Control Of Planar3-RRR Parallel Robot

It’s commonly known that parallel robots’feature of high stiffness, high accuracy andhigh load. Thanks to these features, it has been applied for the situations required multidegrees of freedom, high working load, precise positioning and high speed movement. As aclassic example of parallel robots, planar3-RRR parallel robot inherits these advantages, andcan be used as both planar accurate positioning platform and high speed platform. Thisthesis’s is research purpose is to have a better understanding of planar3-RRR parallel robots’performance of high speed and high accuracy.Firstly, we research on the calibration method of the planar3-RRR parallel robot. Thedimensional error of the components and the joint clearance collectively contribute to thepositioning error of the robot. The existence of the components’ dimensional errors andpositioning error bring differences between the theoretical model and the real robot, and affectrobots’ accuracy. However, it can be discerned with kinematic calibration and compensate.Joints’clearances mainly affect the precision of the robot. But the research on discerning jointand compensating its effect remains rare. Considering the accuracy and precision is equallyimportant when it comes to accurate positioning application, we make an attempt ondiscerning the joint clearance and compensating its effect in real-time control.For realizing high speed trajectory tracking, on one hand we need a suitable controller,on the other hand we need accurate control torque feed forward. I our research we bringaccelerometer into the control system. By acquiring the acceleration in the joint space andworking space, we can more easily discern the inertia and mass parameters. It helps us toreach a more robust controller and more accurate force control.Finally, for realizing high speed and accuracy control, we developed a control systembasing on dSPACE system. We put forward several control models for high speed andaccuracy applications, and discussed the control system’s limitation to the performance.