Design And Experimental Study Of 3-PSR Parallel Mechanism

Since its birth,the parallel mechanism has been well known for its high stiffness,high precision and strong bearing capacity.With the continuous research on the parallel mechanism and the diversified development of the manufacturing industry for more abundant product requirements,the application fields of the parallel mechanism are more and more extensive and the functions are more and more rich.In this paper,the modular symmetric 3-PSR parallel mechanism with three degrees of freedom is taken as the research object,and its component structure is designed,and the related experimental research is carried out.The specific research contents of this paper are as follows:(1)According to the constraint relationship and geometric characteristics of the 3-PSR parallel mechanism,the inverse position solution was analyzed;By introducing the Angle variable of rotating pairs and using the iterative method to solve the Angle of rotating pairs and the position of moving platform,the attitude of moving platform can be solved.Based on Matlab software,parameters such as tilt Angle of P pair in 3-PSR mechanism were changed,and the reachable workspace of the 3-PSR mechanism was ploted by using forward solution under such inclination Angle.Through the numerical comparison of the key dimensions in the workspace,the ideal P-pair tilt Angle is selected.(2)According to the ideal inclination obtained above,the modular Angle platform used by 3-PSR mechanism is designed and processed,and the adjustable motion pair is designed to obtain the adjustable motion pair that can realize a variety of adjustment modes.The prototype body is constructed,and the motion control system is also built.Trajectory tracking experiments of the mechanism were carried out by using laser tracker,and compared with the planned trajectory and the forward solution trajectory.(3)The closed-loop vector chain method was used to obtain the zero-point error model of the mechanism,and the error identification under multiple driving positions was carried out,and the influence of zero-point error on the terminal pose was analyzed.The total error model of the mechanism was established.The geometric relation between the measuring points was used to transform the coordinates,and the zero calibration experiment of the mechanism was carried out with the laser tracker.(4)Based on electronic ruler,wireless acquisition and transceiver system of analog voltage,motion controller and other elements,the wired and wireless control system of the prototype was built,and the upper computer software was written to conduct the wireless control experiment of the prototype.The data were refined and smoothed to improve the follow-up state of the prototype.