Research And Application Of Food Tunnel Furnace Temperature Control System Based On Sliding Mode Control

In recent years,with the continuous development of food enterprises,enterprises are facing increasing competitive pressure.In order to enhance the competitiveness of enterprises,it is necessary to improve the production efficiency and quality of tunnel furnace.Traditional tunnel furnace temperature control system uses PID control,but this method has slow heating speed,large overshoot,which affects the product quality.Therefore,it is necessary to reform and optimize the tunnel furnace.In this paper,the temperature control system of tunnel furnace is deeply studied and analyzed.By using the advantage of sliding mode control which is not disturbed by outside,the sliding mode control is combined with the temperature control system of tunnel furnace to improve the anti-interference ability and work efficiency of the system.Firstly,the structure of temperature control system of tunnel furnace is introduced.According to the different functions of tunnel furnace,the hardware part is divided into combustion system,circulating heating system,conveying system,dehumidification system and software control system.The working principle of tunnel furnace is further introduced.Combining with the actual production process and the operation mode of tunnel furnace,the problems in the working process of tunnel furnace are found out.At the same time,solutions to various problems and control objectives are proposed.By improving some parts of the tunnel furnace,installing motors between the burner and the combustion chamber,installing sensors inside the tunnel furnace,optimizing the information acquisition system of the tunnel furnace.For the additional equipment,configure the corresponding I/O points.The upper computer is used as the platform and the configuration monitoring interface is used as the control platform to monitor the internal operation status of tunnel furnace.Furthermore,the heat transfer modes of each system in tunnel furnace are studied.Based on the analysis of flow transformation and the actual measured data,the heat supplied by the burner,the heat consumed by the product and the heat consumed by the tunnel furnace are calculated,and the thermal efficiency of the tunnel furnace is obtained.Then,the causes of heat loss in tunnel furnace are analyzed,and an improved scheme is put forward.According to the heat conversion of tunnel furnace,the double-volume temperature model is optimized by referring to the boiler model in the dual-volume temperature sliding mode control system,and the mathematical model of the temperature control system of tunnel furnace is obtained.In this paper,sliding mode control is used to control the temperature control system of tunnel furnace.The difference between sliding mode control and other control is that thestructure of sliding mode control is not fixed.In the dynamic process,according to the current state of the system,sliding mode control can constantly change the structure to adapt to the state of the system and ensure that the system moves according to the state trajectory of the predetermined sliding mode.Because the external disturbance has no effect on the sliding mode,the sliding mode control has the advantages of fast response,strong anti-interference ability and easy realization.The stability of the nonlinear system with disturbance is analyzed,and the anti-jamming ability of sliding mode control is verified.Through analysis,we can know that the nonlinear system with interference can reach the sliding surface in finite time,and the system is stable.Thus,it lays a theoretical foundation for the application of sliding mode control in tunnel furnace system.According to the tunnel furnace system,the structure of the controller is determined,and the sliding mode controller is designed.According to the actual field data,the parameters of the sliding mode controller are calculated.Through the system simulation,the control effects of sliding mode control and PID control on tunnel furnace system at 165 ~175 ~C are obtained respectively.The feasibility of sliding mode control in temperature control system of tunnel furnace is verified.