Kinematic Synthesis And Virtual Prototype Development Of A Novel Three Rotational Parallel Mechanism

With the aid of NSFC Project, to meet the demand for the spatial rotational mechanism used in the field of aircraft industry and intelligent robot, this thesis investigates into the design theory and method of a novel three rotational parallel mechanism which is invented by Tianjin University. The following work has been accomplished.1. Kinematic analysis. Referring to the kinematic characteristics of the three rotational parallel mechanism, the Tilt-and-Torsion angles are used to describe the orientation of the platform. Based on the screw theory, three equations involving driving parameters and pose parameters are formulated and proved by an example. And the Jacobian matrix is derived.2. Workspace analysis. The reachable and task workspace definitions of the mechanism are proposed. Then the reachable workspace is searched based on the inverse position analysis with some constrained conditions such as the actuated journey, gemel angles and linkage interference. And the relationships between dimensional parameters and workspace are studied.3. Dimensional synthesis. The influences and ranges of design variables are showed in the performance maps which describe the relationship between the global kinematic performance indexes and the design variables. Considered the geometry and engineering constraints, the kinematic optimization design is completed.4. Virtual prototype design, and the static/dynamic characteristic estimation. The virtual prototype is set up according to the demand of the engineering. Based on this model, the motion simulation and interference checking are carried out and a finite element model is proposed with the aid of ANSYS software. The key parts which affect the static and dynamic characters of the mechanism are identified by the estimation of static stiffness and modal.The above-mentioned outcomes lay a solid foundation for the development of the 3-PUS&S prototype.