Type Synthesis Theory Of Double Parallel Coupling Mechanisms And Synthesis Of New Architectures

The parallel mechanism has the advantages of high precision,large bearing capacity and sensitive dynamic response.However,for the reasons of the interference of components and spatial singularity,the working space of parallel mechanism is generally limited,and the new architectures of parallel manipulators with large working space are still scarce at present.For this problem a configuration method to make two parallel manipulators coupled is proposed in this paper,and a new kind of double parallel coupling mechanism with better workspace is obtained.The digital type synthesis theory of double parallel coupling mechanism is established based on the screw theory and computer technology,and a series of new architectures is published.The principle of double parallel coupling mechanism is studied according to the concept for coupling transmission of motion,and three types of coupling joints and kinematic chains are defined.The general steps to design a double coupling parallel mechanism are summarized.The motion superposition of the mechanism mentioned in this paper is analyzed by the homogeneous coordinate transformation method,and the applicable degree of freedom which can be transmitted by the method is confirmed.The mathematic matrix is used to describe the kinematic chains,and a simplified matrix description method and a full parameter matrix description method are proposed.The mapping relationship between the coupling kinematic chains and the digital description matrix is established.Based on the screw theory,recursive method is used in the progress of motion screw system of coupling kinematic chains calculating by computer automatically.According to the matrix null space theory,The computer solution of constraint screw system of the coupling kinematic chains is realized.Three kinds of coupling kinematic chains databases are established by computer automatically,and the coupling kinematic chains database is established further based on constraint screw system classification.Based on the constraint screw theory,the feasible confinement model of symmetrical parallel mechanism with two rotational,two rotational and one translational degree of freedom are respectively established.According to the principle of constraint screw feature matching and the coupling kinematic chains databases,the symmetrical double parallel coupling mechanism with two rotational,two rotational and one translational degree of freedom are respectively synthesized,and a series of new types of the double parallel coupling mechanism are obtained.In this paper,the special types of the double parallel coupling configuration is systematically studied.The characteristic of four kinds of special double parallel coupling mechanisms and the causes of formation are analyzed,and the specific cases of the relevant mechanisms are given further.By the kinematics analysis of the 3-RRR//RRR double parallel coupling mechanism,the general inverse kinematics method of the double parallel coupling mechanism is given.The 3-RRR//RRR double parallel coupling mechanism is applied to the design of the bionic shoulder joint,and a spherical 3-DOF hybrid bionic shoulder joint prototype is successfully developed.UMAC multi-axis motion controller is used as the control center,the electrical control systems of the bionic shoulder joint prototype are builted,and the basic kinematic experiments of the bionic shoulder joint prototype are completed finally.