Research And Application Of The Embedded System For The Feed Pellet Control System

Granulating is one of the most common steps in the modern feed manufacturing process. In order to keep the quality of products stable and maximize the efficiency, the feed pellet system must be controlled in a given range. Thus a proper automatic controller based on advanced control algorithms has great importance for quality improvement and productivity enhancement.In this thesis, Feed Pellet System is the control subjects, and by summing up the existing theories on control methods for time-delay system, some improvement and innovation are being presented and discussed. Achieve the simulation for the feed pellet process, develop the hardware and software for the controller based on the embedded system with the uC/OSⅡas the operation system. The research of this thesis mainly focuses on the following aspects:1. The history, status of the embedded system and time-delay control system and research content are discussed.2. System Modeling and Simulation. In this thesis, the working principles of the Feed Pellet System are introduced and its mathematical model is derived. By using LabVIEW, the method of IMC-Smith predictor are simulated. Experiment results illustrate that the performance of this control method is better than the conventional time-delay control method on solving the problem of Feed Pellet Control System.3. The Hardware Development for the Embedded Control System. In this thesis, basing on the practical request of the Feed Pellet Control System, an embedded control system is designed, in which the microcontroller ARM7TDMI-LM3S8962 is used as the core. This thesis describes the principles of circuit for each module, achieving the real-time acquisition for temperature and current and control functions.4. The Software Development for the Embedded Control System. This thesis makes a detailed analysis of the kernel of uCosII and its working principles. With this understanding, it makes an introduction about the start-up codes of LM3S8962, replantation process of uCosⅡto LM3S8962 and drivers for each hardware module of the embedded system. 5. IMC-Smith Predictor. Smith predictor is an effective and classical method to compensate for large time-delay in process control system. But the Feed Pellet System has some complex characteristics such as large lag, nonlinearity which cause conventional Smith predictor too sensitive to reach the ideal control effect. In view of this problem, this paper presents a modified Smith predictor structure which is called IMC-Smith predictor, and the parameters of controllers of this modified Smith predictor are derived by IMC principles. All of this modification can improve the performance of system response and enhance the ability of disturbance suppression.In a sum, a Feed Pellet Control System is designed in this paper, which is consisted of the time-delay control method, IMC-Smith predictor and the embedded control platform. This system is a comprehensive and effective control system for Feed Pellet Control System.