The Properties Study Of 3SPU-3SPU Parallel Mechanism

With the development of parallel mechanism research, lower-mobility parallel mechanism has attracted much attention due to their simple and compact in structure, less on drive element, easy control, and low cost, ect. Moreover, they have much more use value and wider apply foreground in production and manufacturing. Based on the analyses of the current situation of the lower-mobility parallel mechanism home and abroad, a novel 3SPU-3SPU parallel symmetrical mechanism with 3-DOF is put forward in this dissertation. This mechanism can perform three translational DOF. In comparison to the traditional parallel mechanism which can perform three translational DOF, the key distinction is that the drive motors of the traditional parallel mechanism usually install on the each branch, however, those of this mechanism all install on the base, and they can control this mechanism through driving the first turning pair of the cardan joint,so then it will realize the purpose of driving near the mechanism,reducting vibration and improving the accuracy. Some theoretical issues on the parallel mechanisms are investigated systematically in this dissertation. Innovation research as follows:(1) Based on the existence of geometry constraints in this mechanism, the forward and inverse position solutions of the parallel mechanism are derived by using vector method and the mathematical notation between the first intersection angle and the second one of the cardan joint, thereby the equations can be obtained; By means of CAD variation geometry approach to built the wire frame simulation mechanisms, it can obtain the simulation solutions which verify the quations.(2) Through the derivation and inversion of the forward position solution s, a Jacobian matrix and a Hessian matrix are derived, thereby the forward and inverse solutions of the velocity and acceleration are derived. MATLAB-based programming, the analytic results are obtained, then those of the kinematics are verified by means of CAD variation geometry approach. The static of the parallel mechanism is analyzed by using virtual work principle, then the force Jacobian matrix is obtained.(3) The entity modeling is built in Solidworks software, then this mechan- ism is analyzed on the state of motion by dynamic simulation. Based on theoretical analysis and MATLAB programming, curses of the inverse kinematics are plotted, which verify the solutions of the dynamics.At last, the interfaces of the forward and inverse position solutions and ones of the forward and inverse velocity solutions on the parallel mechanism are built by MATLAB.