Studies And Elementary Application Of 3PTT Parallel Manipulator

Parallel mechanisms have been used more and more extensive because of thecharacteristic of high rigidity, strong capacity, high precision and compact structure. Parallelmechanism has many kinds of patterns because of the different composition, and threetranslate parallel mechanism is one of the most utility outlook mechanism among them, butanalysis and development to it is too inadequate. In this paper, the following researcheshaving been done to 3PTT parallel mechanism:First, the structural analysis was studied. The kinematics characteristic matrix of theparallel mechanism was obtained through the kinematics characteristic matrix of the serialmechanism and the kinematics characteristic matrix of 3PTT parallel mechanism wasobtained, and the DOF of the mechanism was computed.Second, the coordinate system was set up on 3PTT parallel mechanism and the structuralparameters of the mechanism was defined. The inverse analytic solution was obtainedthrough the vector equation. The jacobian matrix of the 3PTT parallel mechanism wasderived by differential coefficient method and the singularity position was found.Third, the D-H coordinate system was set up on a branch of 3PTT parallel mechanism,the dynamics equation was established by Newton-Euler method and the inverse solution ofdynamics was obtained.Forth, the kinematics and dynamics simulation of 3PTT parallel mechanism was studiedby MATLAB and ADAMS software. Through the simulation, a conclusion can be obtainedthat the theoretical data calculated by MATLAB software was coincident to the emulationaldata obtained by ADAMS simulation. So the kinematics and dynamics analysis was proved tobe correct.Fifth, the design method of parallel machine tool was introduced and a simpleapplication example of 3PTT parallel mechanism used in the machine tool was illustrated.Through above studies, we have had concrete and deeply knowledge to the kinematicsand dynamics characteristic of 3PTT parallel mechanism and this has made a goodfoundation for its application.