Research And Design Of Control System Of Drying Room In Automobile Coating Production Line

In recent years, Chinese automobile industry is gradually mature, however, there remains a big gap between domestic automobile brans and foreign automobile brands. In order to enhance the brand competition, domestic automobile manufacturers have continued to increase investment in technology, upgrade manufacturing technique and improve the quality of products.Drying is a key process in the automobile manufacturing process. Temperature is the most important factor in the process of drying. Due to the increasing demand for the quality of automobile paint film, the traditional control method has shown some limitations. This thesis will take the automobile drying room system as the research abject and take the construction of safe and stable monitoring system as the research targets in order to make study and design on the drying room control system. The drying room control system includes: the design of the electronic control system, the design of the temperature control system, the design of the upper monitoring system.Firstly, the basic structure of automobile drying room has been taken into consideration on the design of the temperature control system. The working principle of the three subsystem like combustion heating, circulation heating and fresh air supply hearing are introducing respectively, on this basis, analysis is made on the inherent characteristics of drying room temperature control system. Then the drying room control system is determined as a nonlinear, time variable, large time delay and strong interference characteristics of complex control systems; System mathematical model is derived from the test determination of circulation heating system. The mathematical model is stimulated and analyzed through PID control and fuzzy PID control.It is found that the mere application of PID control is difficulty in obtaining a better control effect, while the fuzzy PID control can strengthen the captive of uncertainty adapt ability so that a relatively better effect for parameter time-varying or model; The construction of temperature control system composed of industrial control computer, PLC controller, temperature sensor and electric control valve, and under the LabVIEW environment, the fuzzy PID temperature control is compiled.Then, the electronic control system is composed of power system and PLC control system. For the sake of meeting the requirements of drying room system stability and being easy to detect and clear fault, the control circuit of dynamical system is designed into separate power supply.; the circuit diagram of the PLC control system is also designed, and the programming software rslogix5000 is used to compile function program such as automatic start and stop of system, fan control, fault alarm and so on. The long-term stable operation shows that the stability control of the drying equipment is realized.Finally, the author designs the monitoring system. The monitoring system consists of touch screen monitoring system and computer monitoring system. The FactoryTalk view configuration software written touch screen monitor, convenient in drying room scene visually check to see the running state of the drying room and the oven control; under the LabVIEW environment, the preparation of the industrial control PC monitoring program, the realization of the user login, fault information display, temperature data logging curve and history curve query function, realized in the control room to monitor the drying room equipment and process parameters. The long term stable operation of the monitoring system shows that the function of the monitoring system has reached the design requirements.