Research And Design Of Dual Motor Servo System For SMT Machine

SMT machine is very important in the production line of electronic equipment,which can automatically complete the placement of electronic component.Pick up the SMT components by moving the placement head to the designated position and place the components on the corresponding PCB board.In recent years,with the rapid development of electronic industry and the miniaturization of electronic components and the complexity of circuit boards,the demand for the SMT machine is also getting higher and higher in China.At present,A large number of small and medium-sized electronics company are existed in our country,in the preliminary stage of product research and development,A lot of manpower and material resources were spent in making circuit sample.The research of the SMT machine and design of private SMT machine is of great importance to electronic company.In the paper,the desktop SMT machine was developed independently in the laboratory.In order to achieve high speed and precise positioning of the X-Y axis,X-Y axis motion control system of SMT machine were researched and analyzed,and the control system was designed.Firstly the motion of the X-Y axis was analyzed,including the basic motion and combined motion,in order to select appropriate actuator to achieve various motions and achieve motion control of the X-Y axis.Comparison of asynchronous motor,DC servo motor,AC servo motor,we chose the AC servo motor as the actuator of X-Y axis.Around the drive model of AC servo motor,The suitable scheme of the motor control program,dual motor control and double motor position feedback was selected.The implementation of specific programs included the hardware design and software design,the main circuit of double motor drive,control unit,drive unit and power supply were included in the hardware;the software is mainly divided into two aspects: one is the realization of dual motor drive software,including three loop control program of current loop,speed loop and position loop;two is to realize control algorithm of the dual motor linkage.Compare the reference pulse algorithm and algorithm based on data sampling of two kinds of interpolation algorithm,The algorithm based on data sampling was selected as the core of the motion control.In order to optimize the performance of the control system,the speed planning algorithm was added on the basis of the interpolation algorithm,which made the system less impact and higher precision.Finally,according to the actual needs of the placement machine system,the driving servo system of dual motor were tested,the waveform of system was recorded,including the waveform of current loop,speed loop and position loop.And according to the design requirements of the servo,the waveform and data of system were analyzed.The experimental results show that the dual motor driving servo system enhance control of X-Y axis motion on the placement machine significantly and improve the speed and the precision,so the design is valuable in practice for transformation of the SMT machine.