The Design And Research On Hydraulic Synchronous Lift System Based On PWM

With the rapid development of our modern society, some bridges can not satisfymodern traffic any longer. Moreover, to solve problems in building and repairing a bridge,synchronous lift technique has been applied to practical projects as an important techniquein bridge building, reforming and repairing. Synchronous lift technique in a bridge usesthe form of distributed manipulation and centered control to guarantee the safety, efficacyand convenience in projects like bridge renewal, reformation and maintaining. In this way,it also reduces or avoids traffic interruption, lowers the cost and protects the localenvironment.This paper develops a hydraulic synchronous lift system based on PWM by analysingthe principles of synchronous lift in bridge and the requirements of engineering projects.The system mainly includes three subsystems: computer main control subsystem, PWMhydraulic power subsystem and real time monitoring subsystem. So it gathers advancedtechniques such as computer technology, automotive control, hydraulic transmission andcontrol, real time monitoring etc. Through system designing and debugging, it reaches theaccuracy required, and can work efficiently, steadily and safely.Firstly, analyse the principles of bridge lifting and then complete the overall conceptdesign of the system based on technical parameters and construction requirements. Byanalysing and improving the existing hydraulic system, an electrical schematic and thedirection of designing the monitoring system are achieved.Secondly, specifically introduce the hardware and software of the control system. Thehardware is mainly comprised of PLC control units. The equipment model andconfiguration are decided according to I/O requirements. A detailed circuit diagram is alsoprovided in this part. The software part introduces S7-200programming of the four-pointsynchronous lift system, S7-300programming of the main station, and the user interfacedesign. The generation of PWM signal is emphasisly described here.Finally, through simulation debugging and real equipment debugging, the wholesystem meets the designing and construction demands.