Study&Design Of Environment Monitoring System For Refrigerated Container

Nowadays as the economic globalization deepens, refrigerating transportation has been developing rapidly.Safety problems of transportation of fresh goods are getting widespread attention,and safe and stable means of transportation has great economic benefits.In terms refrigerating transportation vehicles, refrigerated container is replacing refrigerated ships step by step,and its proportion is getting bigger. In recent years intelligent control technology has achieved great development and because of its unique superiority and broad development prospects in the field of control research, more and more scientific researchers apply the intelligent control technology to the research of refrigerated container environment monitoring system.Refrigerated container environment monitoring system uses ARM9as the core of its hardware platform. The author writes programme for frequency conversion control using control algorithm,and uses the ZigBee wireless data transmission technology to monitor such environment factors in the container as temperature, humidity etc. as well as to monitor and control the running state of compressor, fans and humidifier on a real-time basis. This paper adopts the modular design method to design the hardware system and this way a core control board using S3C2440A and the frequency conversion control and driving circuit are designed. It builds the Linux embedded software platform as its software system.Using fuzzy theory, this article designs the self-adaptive fuzzy PID control algorithm to achieve frequency conversion control of the compressor. Results of the MATLAB simulation show that it has smaller overshoot compared with that of the conventional PID control and the system achieves stable state in a short period of time.Using ZigBee wireless data transmission technology, this system resolves the problem that it's hard to flexibly form network and wire when using wired data transmission.And this paper studies and discusses the networked control of refrigerated container ships.The experiment results show that the system can achieve stable state in a relatively short time and the wireless data transmission is reliable, thus this system is capable to effectively achieve the frequency conversion control of the motors.The algorithm is concise and highly efficient and meets the requirement of real-timing of the refrigerated container monitoring system and thus fulfills expectations.