Research On Identification Model And Modification Method For Mobility Design Defects Of Mechanisms

The design defects identification and modification of mechanical products are key factors for enhancing design efficiency and ensuring design quality. Taking the design defect identification as main clue, the identification and modification for circuit defect, branch defect, dexterity design defect and rotation ability design defect in mechanisms are studied deeply and systematically.The circuit defect and branch defect are the usual design defects during the kinematic synthesis of linkage mechanism and the spherical four-bar mechanism is regarded as the research object. By using the mapping function form Euclidean space to Conformal space, the Conformal model of the spherical four-bar mechanism is established. The representation of configuration for the precision points is given based on the Conformal model of the spherical four-bar mechanism and the algebra calculation rules in Conformal Geometric Algebra. The circuit defect or branch defect of the mechanism could be distinguished by whether the configurations of all the precision points are the same. The distance curve of the mechanism is established by the inner product of the Conformal Geometric Algebra and the identification of circuit for the spherical four-bar mechanism is realized based on the distance curve of the mechanism and the limit lines. The circuit defect of the mechanism could be distinguished by whether all the precision points are located on the same circuit. The modification for circuit defect or branch defect is implemented by using simulated annealing optimization algorithm to optimize the input or output values for mechanism with circuit defect or branch defect.Aiming at the dexterity design defect, the spherical serial mechanism with three degree of freedom is regarded as the research object. Link coordinate systems for the spherical serial mechanism are created by the D-H method. Based on the theory of the Conformal Geometric Algebra and the link coordinate systems for the mechanism, the analytic solution for the inverse kinematics is obtained, and the service region is defined by this analytic solution. The calculation of the dexterity is implemented based on the service region and the service circle. The dexterity design defect for the spherical mechanism is distinguished by whether the dexterity meet the design requirement. The modification for dexterity design defect is implemented by using improved particle swarm optimization algorithm to optimize the values of the link for mechanism with dexterity design defect.Aiming at the rotation ability design defect, the 2T1 R parallel robot is regarded as the research object. The Conformal model of 2T1 R parallel manipulator is established by using the mapping function form the Euclidean space to the Conformal space. Based on the Conformal model of the parallel mechanism and the algebra operation in Conformal Geometric Algebra, the identification method for rotation ability design defect is put forward. The modification for rotation ability design defect is implemented by using improved bacterial colony chemotaxis algorithm to optimize the values of the link for mechanism with rotation ability design defect.Identification and modification model for circuit defect, branch defect, dexterity design defect and rotation ability design defect provide effective theories, methodologies and techniques for the identification and modification of mechanism design defects.