Development Of Precision Assembly And Welding System For Miniature Base Assembly

Accelerometer is the main part of inertial navigation,widely used in aviation,aerospace and other fields,its performance has a great impact on the accuracy of navigation and guidance.At present,the production of accelerometer base components mainly relies on manual assembly and welding,but manual assembly has problems such as low precision and efficiency,low yield,poor product consistency,and welding process requires high technical level of workers,so it is difficult to achieve mass production.Aiming at the above problems,an automatic precision assembly and welding equipment for the accelerometer base assembly was developed to meet the current production requirements.Firstly,according to the characteristics of the accelerometer base component and assembly technical requirements,the overall scheme of the assembly system is optimized.In order to solve the problems of difficult clamping and easy clamping of the suspension wire,difficult picking up of the pendulum component and poor welding quality,the fixture and control system at the end of the assembly system are improved and optimized to ensure the function stability of the assembly system.Secondly,based on the system hardware and equipment functional requirements,the overall control system of the base component assembly equipment is designed,and the control strategy of the suspension tensioning force based on the closed-loop feedback of the tension sensor and the strategy of the micro-hole wire penetration and self-altering based on machine vision feedback/guidance are formulated.The automatic welding process of acceleration base component was developed by adopting the force-visual feedback based automatic welding technology and PID based temperature control mode to improve the assembly efficiency of base component.Among them,in order to realize the pose detection of the accelerometer base component,a better image processing algorithm is adopted to realize the pose recognition and accurate positioning of the target part.Adaptive step size auto-focusing algorithm is adopted to solve the problem that the captured images are separated from the camera depth of field due to the consistency difference of parts.To test the hardware function and calibration assembly key parameters,based on the layered architecture of software framework and multithreaded programming technology,development of automatic assembly system control software,design the friendly human-computer interaction interface,realize the automatic assembling of accelerometer base components and welding function,get rid of the component assembly dependence on the assembly workers technical level.In addition,the system debugging software is developed based on the modular idea to facilitate the independent testing of each hardware,realize the control of the system hardware and the collection of force,temperature and position information,and lay a foundation for the implementation of subsequent assembly control software.Based on the assembly precision and welding quality requirements of the accelerometer base component,the factors affecting the assembly precision of the components to be assembled were analyzed,the system parameters to be calibrated were determined,and the calibration and compensation scheme of the key parameters of the assembly system was developed.Based on the vision measurement system and the assembly system,the corresponding error compensation model was established,and the key parameters of the system were corrected by the assembly control software,so as to ensure the assembly accuracy of components and the product yield.Finally,the assembly experiment results show that the clearance position accuracy of the pendulum component is better than 20?m after assembly,the tension force of the suspension wire and the welding quality meet the assembly technical requirements of the accelerometer base component,and the product consistency and assembly efficiency are effectively improved.