【作者】 李志辉；

【导师】 孙丽萍；

【作者基本信息】 东北林业大学 ， 农业电气化与自动化， 2010， 硕士

【摘要】 木材干燥是提高木材利用率、节约木材的一项重要措施。微波-真空干燥是一种具有极快干燥速度、不污染环境等优点的低温干燥新技术,该技术结合了微波加热和真空干燥两项技术的优点,不仅能克服单独微波干燥过程中因温度过高而易出现内裂和内部烧焦的缺陷,又能轻易解决单独真空干燥过程中因空气介质稀少而使热量传递困难的问题,还能降低干燥成本,大幅度减少干燥时间,所以将微波-真空干燥技术应用于木材干燥是一项具有巨大发展前景和应用价值的技术。微波-真空木材干燥过程呈现非线性及不确定性等特点,为其设计高效合理的自控控制系统也变得尤为重要。针对花旗松的微波-真空干燥工艺,建立了时间序列下木材干燥的ARMA数学模型。在木材干燥控制过程进行理论分析的基础上,结合模糊控制的智能性与常规PID控制的可靠性,设计了一种Fuzzy-PID自整定控制器,采用模糊推理的方法实现PID参数的在线整定。应用MATLAB/Simulink工具对干燥窑常规PID控制和Fuzzy-PID自整定控制进行仿真,通过分析与比较得到：Fuzzy-PID自整定控制器的阶跃响应曲线具有上升快,稳态性能好,过渡过程时间短,超调量小的优点,控制特性满足系统的要求。这对提高木材干燥过程的控制水平,有效地保证木材干燥质量、降低能源消耗和减少成本,具有重要的理论研究和实际指导意义。结合Fuzzy-PID自整定控制算法运算量大,需要保证实时性的特点,对系统的硬件实现进行了探索分析,选取了TI公司控制系列的TMS320LF2407A作为处理器。为了降低开发人员编写DSP代码的难度和工作量,提高整个DSP系统的性能和可行性,给出了MATLAB/Simulink平台上DSP代码开发的设计流程。基于Fuzzy-PID自整定微波-真空木材干燥控制系统策略的设计,提高了控制系统的精度和稳定性,在利用先进控制算法解决生产实际问题上做了有益的尝试。同时,使系统结构设计更加合理、实用性强,很好的满足了微波-真空木材干燥自动化控制的要求。更多还原

【Abstract】 Wood drying is an important measure to economize on wood and increase its utilization. Microwave-Vacuum drying(MVD) is low-temperature drying technologies with fast drying rate and environmental advantages, which combines with two technical advantages of microwave heating and vacuum drying. It not only can overcome that individual microwave drying process is vulnerable within the crack and internal burnt defects because of high temperature, but also resolves the heat transfer problems easily making by air media scarcity in separate vacuum drying process, meamwhile, the drying costs is reduced and the drying time is decreased substantially. Consequently, it’s a great development and application of technology that the microwave-vacuum drying technology applied to wood drying.Microwave-vacuum drying of wood process has some characteristics such as nonlinear, hysteresis quality, uncertainties and so on, so as to design effective automation control system becomes particularly important. A fuzzy self-tuning PID controller is designed on the basis of theoretical analysis of wood drying control procedures, combining with fuzzy control’s intelligence and conventional PID control reliability, fuzzy inference method is used to implement a PID online setting. Based on MATLAB/Simulink tools for simulation, by simulation, analysis and comparison of conventional PID and fuzzy self-tuning PID control of drying kiln, it’s showed that the step response curve controlled by fuzzy self-tuning PID has risen fast, steady performance, short transition process time, small overshoot and other advantages like this, control features meet the system requirements. This will increase the wood drying process control level, guarantee the wood drying quality effectively, decrease energy consumption and reduce costs, which have important meaningful for theoretical research and practical application.With the characteristic of large algorithm operational capacity for fuzzy self-tunig PID, at the same time the need to ensure that real-time features, hardware implementation approach is explored, TMS320LF2407A DSPs from TI company control series is selected as the processor. In order to reduce difficulty and workload to write DSP code for the developers, improve overall DSP system performance and feasibility, the MATLAB/Simulink platform DSP code development and design process is given.This article propose the microwave-vacuum drying of wood control system based on fuzzy self-tuing PID, increased the control accuracy and stability, It is an beneficial attempt taking advantage of advanced process control algorithms to solve the actual problem. Meanwhile, system architecture design is reasonable, practical and satisfied for the automation control requirements microwave-vacuum drying of wood.更多还原