A Design And Implementation Of Wood Drying Kiln Measure And Control Module

In the whole world, with the improving of people’s requirements of life, woodenfurniture and wooden decoration products gradually won consumers. However, we are facedwith the reality of the rapid decline in the forest resources. The concerning about thedeterioration of the environment inevitably leads to fewer output of wood raw material. Thus,the more efficient, low cost use of limited forest resources becomes very important.A reasonable drying process is a key step in the industry before making raw materialsinto finished products. Otherwise, with the drying of the woods, different parts of them willhave a different shrinkage, witch will produce warping, breaking or other deformation. Thereare many methods for drying wood including air drying method, wood drying kiln methodand some other special methods. Among them, the drying kiln method is the most popular.But, with a long drying cycle, a complex baseline controlling, it’s hard to handling forworkers. How to simplify the drying kiln drying process, improve the quality of wood andreduce labor costs are the urgent problem to resolve.Embedded control system is a good choice. An embedded system is a computer systemwith a dedicated function within a larger mechanical or electrical system, often with real-timecomputing constraints. It is embedded as part of a complete device often including hardwareand mechanical parts. The key characteristic, however, is being dedicated to handle aparticular work. Since the embedded system is dedicated to specific tasks, design engineerscan optimize it to reduce the size and cost of the product and increase the reliability andperformance. Some embedded systems are mass-produced, benefiting from economies ofscale. Therefore, the implementation of embedded system in wood drying kiln process is veryrealistic. It helps to produce low-cost, high-quality, large-scale production. And ultimately, itwill reduce costs, improve efficiency, improve utilization of woods, reducing forest loss.Currently, most wood drying kiln control systems have a single function, a backwardtechnology. It’s a product of the last century. The main drawback of them is the lack ofself-control of the drying process, the low automation and the scale limitation.Based on the analysis of the functional and non-functional requirements of distributedwood drying system, this paper established the direction of research and design. This distributed design is also a modular design. The system consists of four modules: PC monitormodule, main control module, measure module and control module. These modules aredivided into three levels: PC monitor module is responsible for monitoring a plurality of wooddrying kiln; main control module is responsible for single kiln drying process, monitoring andhuman-machine interaction; measure module is responsible for the single kiln sensor datameasuring and processing; control module is responsible for receiving control commandsfrom main control module and have a real-time controlling of the drying kiln devices. Themain content of this paper is the research of lower level measure module and control module.Based on the overall design of the wood drying kiln control system, this paper analyzesthe design of a single kiln measure module and control module. First, based on the Arduinotechnology platform and the requirements of the two modules, circuit diagrams are given andthe key parts are analyzed. RS485bus communication technology is utilized in thecommunication between the two modules and the main control module. And the main controlmodule is the master node; the measure module and the control module are the slave nodes.Then, based on the hardware platform, the software designs of the two modules areproposed. Communication software is a key aspect of software design. The communicationprotocol, the master-slave handshake and communication state machine is confirmed incommunication design. Measure module and control module take a similar main programstructure. For the limitations of the Arduino hardware resources, state machine approach iswidely used in program design to improve the response speed of the system.At the end, experiments and tests carried out for the designed and implemented result. Itshows that the communication is normal; each functional unit is operated normally. It is inline with expectations.The measure module and control module achieved in this paper is an important parts ofthe distributed wood drying control system. This modular, self-controlled drying processdesign will be able to greatly enhance the drying effect of wood, improve wood utilization,and reduce labor costs.