| Parallel mechanism with few degrees of freedom not only has the advantages of flexiblemovement, compact structure, high rigidity, high precision, strong bearing capacity, but alsohas the characteristics of low cost, easy to control. Planar3-DOF parallel mechanism is a kindof important component of parallel mechanism with less degrees of freedom. It has wideapplication in various fields.This paper systematically studies the3-PRP planar3-DOF parallel mechanism (the3-PRP mechanism for short), and mainly analyzes positive and inverse solutions of thismechanism, singular configuration, reachable workspace and stiffness characteristics.Firstly, the kinematics property of the3-PRP mechanism is analyzed. Using thecoordinate transformation method to establish its motion constraint equations to analyze thepositive and inverse kinematics of the mechanism, and then the positive and inversekinematics of position are derived; Then, on the basis of kinematic analysis of the movingplatform, it can figure out the speed, acceleration of mechanism moving platform and also theJacobian matrix.Secondly, singularity of3-PRP mechanism is analyzed. The singularities are divided intothree types. The result is that the3-PRP mechanism singularity within the workspace is free;The limit boundary search method is adopted to simulate the workspace, and also with thehelp of MATLAB software, the workspace of the3-PRP mechanism is solved. By changingthe input and output range of the mechanism, it comes to the conclusion that the change ofinput and output has a deep effect on the shape and size of the3-PRP mechanism’s reachableworkspace; Finally, the condition number of Jacobian matrix is obtained by analyzing thedexterity of the3-PRP mechanism.Then, the dissertation using the new conservative coordinate conversion stiffness matrixderived rigidity the3-PRP mechanism stiffness components are on the direction of X axis andY axis and attitude angle, and using MATLAB software, the stiffness mapping curve insideworkspace is obtained under the situation that attitude angle is given, what’s more, according to the stiffness mapping curve, the stiffness characteristics of the3-PRP mechanism areanalyzed.Finally, This section studies the mechanism kinematics simulation. Three-dimensionalmodeling software UG8.0is used to establish the model of the mechanism. After the modelsassembled, they are imported into simulation software ADAMS to add constraints andestablish the virtual prototype of the3-PRP mechanism. The simulation is carried out on themechanism separately driven by single axis, two and three-axis kinematics. By changing thesettings of the driving function, it can figure out the impact of the driving on mechanism’smotion parameters. |
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