| Electromagnetic riveting(EMR)is an advanced joint technology of upsetting rivets quickly by using electromagnetic force generated by alternating magnetic field.It has the advantages of large riveting force,no pollution and good material adaptability,and has broad application prospects in automotive and aerospace fields.Aiming at the potential application requirements of electromagnetic riveting in automatic production,a fully coupled finite element model of electromagnetic riveting was established in this paper to study the influence of structural parameters of discharge coils in electromagnetic riveting equipment on its performance.Then based on the analysis results,an automatic electromagnetic riveter was designed and manufactured for industrial robots.At the same time,the common route planning problems in robot automatic riveting were explored.Firstly,the fully coupled electromagnetic riveting model was established by using LS-DYNA software,and the model was verified.On this basis,the structural parameters of the core component of the discharge coil were studied,and the influence of the section shape,height and width on the riveting force and energy saving effect was analyzed.The results showed that the performance of rectangular coil and trapezoidal coil was better,the difference of each index of the two coils was less than 2%,but the processing cost of rectangular coil was lower,and it was more suitable for the manufacture of rivet gun.In addition,with the increase of the height of the rectangular section coil,the performance indexes decreased slightly.But when the coil width decreased,each index increased obviously.Secondly,the automatic electromagnetic riveter was designed and manufactured.The power,shock absorption and body of the riveter were analyzed.Then,referring to the numerical simulation results,the modeling design of each part was completed in Solid Works software,and the riveter was manufactured and tested.The test results showed that the rivet forming was uniform,and the size of pier head met the relevant standards.The variation of pier head size was less than 3%,and the riveting quality and repeatability of riveter met the requirements.Finally,the riveting route of multi-row multi-rivet structure was planned based on the automatic electromagnetic rivet gun manufactured.The shortest riveting route model was established based on genetic algorithm,and the riveting route of robot was optimized.The length of optimized route 1′ was 30.09% shorter than that of the initial route 1.The optimized route 2′ was 16.48% shorter than the initial route 2,and the maximum deformation and maximum residual stress were reduced by 136.84% and 10.1%.At the same time,compared with route 1′ without deformation,the maximum deformation and maximum residual stress of route 2′ with deformation were reduced by 87.72% and 6.3%,and the route length was increased by 9.6%.In addition,the finite element model of multi-row and multi-rivet was verified. |
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