Research On Double Joint Module Of Self-Driving Articulated Arm Coordinate Measuring Machine

The traditional articulated arm coordinate measuring machine adopts three rotating single joints and three swinging single joints interlaced arrangement in series,which has the advantages of measuring angle flexibility and ease of operation,and is widely used in the processing site of precision workpieces for online inspection and measurement.With the progress of the times,the six-degree-of-freedom self-driving articulated arm coordinate measuring machine composed of a single joint has problems such as difficulty in kinematic inverse solution and large manufacturing and installation errors,which is difficult to meet the high-precision,low-error measurement needs put forward by the increasingly intelligent manufacturing industry.Based on the comprehensive consideration of the scientific research results of modular drive joints at home and abroad and the analysis of the working principle of the articulated arm measuring machine,this paper proposes the design idea of an integrated double-joint module,which integrates the pitch joint and the rotary joint in a joint module to improve the overall structure of the measuring machine and improve its measurement accuracyFirstly,through a large number of investigations on the research results and current status of modular drive joints at home and abroad,combined with the structural principle and performance indicators of self-driving articulated arm measuring machine,the design index of the double joint module of self-driving joint arm measuring machine is proposed.The exterior of the double-joint module adopts an integrated structural design,and the internal adopts a transmission scheme of brushless DC motor drive,harmonic reducer deceleration and electromagnetic brake safety protection.And from the overall structure of the measuring machine,the mechanica l analysis is carried out,and the torque required by the double joint module is estimated,so as to select the specific model of each transmission component inside the joint;Secondly,the three-dimensional structure assembly of the double-joint module is completed in the SOLIDWORKS software;In ADAMS software,the dynamic simulation of the double joint is verified,and the performance of the simulated torque and output speed of the joint is obtained,which provides a reference for the motion control of the selected motor and reducer.ANSYS Workbench was used to analyze the static deformation and biaxial perpendicularity of the bi-joint module,and to optimize the structure of the joint shell,end cap,and other components.The results show that the maximum static deformation of the double-joint module is 0.02208 mm,the maximum flexible deformation of the structure is 0.011029 mm,and the verticality error between the joint spindles is 7.2".The optimized joint shell and end cap volume are reduced by 9% and 12%,respectively,to meet the design requirements for double joint stiffness and precision.Then,the static error source and dynamic error source of the double joint module are systematically analyzed,and the error model is mainly established from three aspects,namely the structure manufacturing and installation error of the double joint module,the rotation angle error inside the joint module,and the bending error of the connecting shell between the double joints.In ANSYS,the static deformation of th e error on the biarticular structure is simulated and verified with the error in the theoretical model,and the average ratio of the angle ratio between theory and experiment is 0.134,which proves the correctness of the theoretical analysis and simulation results.Finally,the hardware circuit design of the synchronous measurement and control circuit system of the double-joint module is carried out,and the interface circuits such as motor drive,encoder,current detection,and system power supply are designed respectively.Matlab/Simulink is used to complete the modeling of the dual-motor synchronous control program,realize the setting of the host computer interface in Labview,build two brushless DC motor synchronous control experimental platforms,and verify the feasibility and stability of the BLDC synchronous control program of the two brushless DC motors in the double-joint measurement and control system.Fig [99] Table [20] Reference [86]...