Design Of Synchronous Lifting Control System For Large Antenna

In order to measure the electrical properties of large spaceborne expandable reflector antenna on the ground to guide its structural design,it is necessary to carry out the zero gravity suspension experiment of the antenna.Before the experiment,the antenna should be suspended to a specified height,and ensure its lifting accuracy requirements.The electrical performance of the antenna depends on the accuracy of the surface of the reflector,and the surface accuracy of the reflective surface is susceptible to the self-weight of the antenna.Therefore,a large antenna synchronous lifting control system is designed.The gravity of the antenna is offset by the suspension tension,and the antenna can be lifted to a specified height with a specified lifting accuracy.According to the comprehensive analysis of the characteristics and control requirements of the system,the overall control system program is made.In order to achieve the automation of control needs,the system uses PLC as the main controller and use touch screen as a human-computer interaction interface.The system can achieve remote control through the Ethernet communication between the touch screen and PLC.PLC control the servo motor to drive the mechanical actuator to achieve the lifting function of system.To ensure movement precision,semi-closed-loop control strategy is employed.In this control system,encoders supplied with the servo motors are used to monitor the position parameters of the antenna.These parameters are sent to PLC via modbus communication and then transferred to the touch screen.On the basis of the overall scheme,the main controller,touch screen,motor drive system feedback device and lifting device of the system are selected.Complete the control system hardware circuit design,then interface of the touch screen is designed and the overall framework of the PLC program is developed.After the completion of hardware and software design,the hardware debugging,software debugging,laboratory debugging and on-site debugging of the system are completed.The synchronous lifting system has three operating modes,that is a single point of lifting,five-point synchronous lifting and automatic operation mode.The touch screen can be used to set the lifting displacement and speed parameters of the antenna and display varieties of operating conditions of the system.