Robotic Micromanipulation For Precise Assembly And Soldering

With the acceleration of social information process,the demand for intelligent devices is also explosive growth.As a key process in electron industry,the efficiency and quality of electronic assembly and soldering directly affect the capacity and reliability of intelligent equipment.Although recent progress in soldering robot has greatly improved the productivity,how to deal with the offset of metal pin and through hole center is still a big challenge,which may affect the soldering quality,reduce the product reliability or even result in failure.Moreover,it is time-consuming to determine the process parameters of different sizes of solder joints on PCB by trained process engineers,and this manual based mode is subjective and lack of unified standards,and the soldering process parameters obtained by different process engineers are also different.This paper aims to solve these problems in practical electronic soldering industry.1)The pin alignment is carried out to eliminate the soldering defects caused by the offset between the pin of electronic components and the through-hole axis.For pin alignment,the springback movement of the pin after removing the external force must be compensated to ensure the accuracy of pin alignment.To adress this,this paper first carries out a mechanical analysis of the pin's deformation based on the elastoplastic deformation theory.Then,the springback movement of the metal pin after removing the external force in the air and with the interference of molten solder is analyzed,and the prediction method of springback displacement is also proposed.2)This paper proposes a hybrid visual servoing control method for precise pin alignment.The position-based target region arriving controller is used to control the manipulator to quickly reach the target region in the field of view;After a continuous control mode switching function is enabled,the image-based pin alignment controller with springback compensation controls the manipulator to push the pin to reach the desired position in the image space.After removing the manipulator,the pin's free end spontaneously back to the through-hole axis.3)This paper also proposes a vision-based key soldering process parameter decision method is proposed to replace the time-consuming manual-debugging method.Firstly,a multi-input required solder volume calculation model for through-hole components is established.Then,a vision-based key soldering parameter automatic determination method is proposed based on this calculation model.Finally,practical robotic soldering experiments on three kinds of electronic components are carried out to verify the effectiveness and robustness of the proposed prediction model for metal pin's springback,the hybrid visual servoing control method for micromanipulation and the vision-based key soldering parameter automatic determination method.