Research On Articulation Module Of Self-driven AACMM

The traditional AACMM(Articulated Arm Coordinate Measuring Machine)is widely used in automobile,aviation and other machinery manufacturing field because of its wide measurement range,good portability and wide measurement space.With the current intelligent manufacturing field of automatic equipment,in order to improve the demand of online and mass measurement,the traditional AACMM can not meet the requirements above because of its low efficiency,poor path planning,larger subjective error.The repeatability is mainly influenced by the manual pulling measuring mode.This paper based on the researchs of the traditional AACMM,combining with the beneficial results of the existing industrial robotic arm,put forward the idea of replacing the existing unpowered joint with automatic joint which includes brushless motor,harmonic reducer as well as precision shaft.By using such joints to construct the Self-driven AACMM.Main research work is as follows:At first,this paper inrtroduces and analyzes the present research situation and problems of AACMM at home and abroad.Studying the differences of structure characteristics between ACMM and light machine arm.Then point out the the key point of designing a Self-driven AACMM based on the existing AACMM.Based on the theory and simulation method,the design of the modular configuration of the self-driven AACMM is carried out.A simplified model of the structure is established.The mechanical model of torque and acceleration is established,the size of the whole machine and the size of each joint are estimated and the device is selected.Based on the virtual prototyping technology,a virtual prototype of the self-driven AACMM is established.The rationality of the above estimation model is evaluated by simulation,the parameters of the joint are evaluated,and the joint components are optimized with the further simulation resultsDesigned and developed the measurement and control circuit.The circuit takes the stm32f407 microcontroller as the core,including the grating encoder data acquisition,the probe trigger circuit,the motor driver control and the joint communication circuit.The software corresponding to the circuit is designed.The Joint module prototype is developed,the repeatability experiment is carried out under different touching frequency,speed and each side.The results show that the abrupt change of speed and acceleration must be reduced and the repeatability error is decreased by the method of improving the control methods.In the bilateral experiment,when the speed is less than 1.53rad/s,the probability of the trigger rebound is smaller,and the maximum repeatability error is ±2.11″.The joint structure parameter calibration model is established,and the joint structure parameters are calibrated,measured and validated by controlling the motor at the 0.23rad/s speed.The experimental results show that the technical scheme is feasible.The research results provide an important basis for the research of the self-driven AACMM.