Type Synthesis Of Rotational Decoupled Parallel Mechanisms And Analysis Of The Novel Mechanism

The parallel mechanism has been applied in many fields for the dual relationshipbetween it and the serial mechanism on structure and performance characteristics. As oneimportant branch of the parallel mechanism, the rotational parallel mechanism has beenwidely used in the fields which need spatial orientation, such as ship motion simulationplatform, target tracking, etc, however, Strong coupling is a prominent feature of theparallel mechanism, and it makes the design, analysis, assembly, and development of thecontrol system of the parallel mechanism very complicated, This thesis aiming at thecoupling problems of parallel mechanisms, the type synthesis method of the rotationaldecoupled parallel mechanisms will be proposed. According to this method, the typesynthesis of the rotational decoupled parallel mechanisms will be performed. The maincontributions are as follows:This paper collects the existing rotational decoupled parallel mechanisms,realization conditions of rotational degrees of freedom of the mechanism and criterion fortype synthesis of the branches are proposed, then the type synthesis theory of therotational decoupled parallel mechanisms will be constructed based on constraintsynthesis method, the type synthesis of the rotational decoupled parallel mechanisms isperformed using the proposed theory and Many novel mechanisms are obtained. Theexistence and existence condition of three degrees of freedom rotational fully decoupledparallel mechanism are illuminated, and some three degrees of freedom rotational fullydecoupled parallel mechanisms are given.A novel mechanism is selected from many rotational decoupled parallel mechanismshave been obtained by Optimization selection. Aimed at this mechanism, kinematicsanalyses are conducted and the kinematics equations are also established, thus derivingand formulating the direct and reverse solutions of position, velocity and acceleration,The workspace and singular configuration of those two mechanisms are analyzed and theworkspace is simulated through MATLAB.Under the guarantee of the parallel mechanism has good transmission performance，meanwhile，taking minimization of attitude error of moving platform as the target theoptimized objective function was established, and the overall optimal solution is acquiredby adopting the genetic algorithm．Three-dimensional model is established in Pro/E based on the overall optimal solution, moreover, simulation model is built with ADAMS, motion trajectory planningand simulation of moving platform is performed, the displacement curves and velocityand acceleration curves of the actuators are drawn, and further for dynamic analysis.