Research On Temperature And Humidity Control Method Of 1m~3 Climate Box Based On Event-triggered Strategy

China is a large country of production of wood-based panel.Total production and demand have reached the world.The wood-based panel products are widely used in the decoration and furniture fields for home,office and public places.However,formaldehyde released by the wood-based panels has been listed as a first-class carcinogen by the World Health Organization,and the formaldehyde release period released in the artificial sheet material is 3 to 15 years.Therefore,governments attach great importance to formaldehyde release problems with wood-based panels and their products.Developed countries such as the United States,Japan,Germany have formulated a resident aldehyde release limit of wood-based panels and their products in the form of legal or mandatory standards,respectively,ensuring people's health and safety.As of now,the detection of formaldehyde release in all countries is to limit the amount of formaldehyde release of the wood-based panel and its products using 1m~3 climate chamber method.The 1m~3 climate chamber method is a quantitative dew point saturated water vapor to deliver the quantitative dew point in the box in a 1m~3 in the closed space,and the quantification of mixed air is excluded in the box,and the air speed in the case in the case is flow in the case where the wind speed is fixed.The time for detecting the sample is 3 to 28 days,while fog and condensation are not allowed in any time.Therefore,the climate chamber method is used to measure the limit of formaldehyde release which is difficult to achieve high control accuracy.Like other countries,China also includes this method in the mandatory national standard GB 18580-2017.At present,the measurement accuracy of the 1m~3 climate chamber above China is just the maximum error allowed by the national standard,and the time to reach the steady state lasts long,causing a lot of resource waste,and the redundant use of the communication channel.Taking only 28 days to calculate,the electric energy consumed by a refrigeration compressor with an operating power of 4KW is 2688KW·h.If a statutory inspection department has 30 detection boxes,the electric energy consumed per year can reach 3*106KW·h.Under the general trend of energy saving and emission reduction in our country,the energy saving of 1m~3 climate chamber has become a problem that must be solved in the industry.Therefore,this dissertation is for the current problems of 1m~3 climate chamber method,and proposes an idea based on an event triggering strategy.The temperature and humidity control system is used to model the climate chamber temperature and humidity control system.Using the modern control theory,the controller can be designed to achieve temperature and humidity in climate room with fast precision control and resource saving effect.Besides,this dissertation also develops an 1m~3 climate chamber,completing hardware selection and software design,and performs field experiments to verify the feasibility of the control algorithm proposed in this dissertation.The main research work of the dissertation is as follows:First,in theory,the working mechanism of each part of the climate chamber is analyzed,and the thermodynamic differential equation of the climate chamber temperature and humidity control system based on the law of energy conservation law is modeled.Since the system model is a multi-input multi-output system,there is a coupling phenomenon between system variables.This dissertation uses a sliding mode controller to control,and four event-triggered rules are designed,in theory,the climate chamber operation process reduces redundant resources.The control effect does not exceed the national standard allowed error,and the sliding mode controller and the PID controller simulations are compared according to the written event-triggered rules.Next,this dissertation analyzes the hardware structure of 1m~3 climate chamber and hardware demand.According to the inspection principle,the temperature control system,humidity control system,climate chamber and control system are briefly described and the main hardware selection is completed.A schematic and physical map of each part system is given.Then,combined with the proposed event-triggered strategies,this dissertation has completed the programming of the ladder diagram control program on STEP 7-Micro WIN SMART software,and designed the human-computer interaction interface using Win CC flexible SMART software,and completes the communication with the PLC.Finally,this dissertation has conducted a field experiment of 1m~3 climate chamber temperature and humidity control algorithm,and the experimental results were compared with the simulation results.The reliability of the established temperature and humidity control model is described,and the event-triggered strategies for this dissertation design are verified.The control effect is better than the national standard,and the control speed is faster than most equipment at home and abroad;and it is concluded with the control effect without an event trigger policy.The algorithm has played a certain situation in the case of the control speed and control effect saving the role of resource.