基于自适应Smith控制率的煤样燃点检测仪表温度控制系统

摘要

煤样的燃点是煤炭的重要物理属性,是煤炭开发、运输及使用过程中的重要的技术参数；针对煤样燃点检测中温度控制的工程需要,介绍了一种基于AT89C55单片机内核的煤样燃点检测仪表设计方法,重点研究了其温度控制系统的特点、关键技术问题及其解决办法；为了有效地解决对于煤样加热炉这一时滞、大惯性、时变参数受控对象的控制问题,采用了一种基于指数遗忘的递推最小二乘算法(Recursive Least Squares with Exponential Forgetting,RLSEF)的Smith控制器(Smith Controller)；仿真结果表明该自适应Smith控制器可以有效地补偿受控对象的时滞、大惯性特性,并能很好地适应系统参数的变化.当加热炉惯性时间常数在2000～6000s间按正弦规律交替变化时,在温度上升到64.9℃后,实际升温速度就可进入要求的升温速度(5士0.25℃/min)的范围之内,满足该仪表的设计要求.%The burning point of coal sample is a crucial physical property of coal, and it is also a key technical parameter for the exploitation, transportation, and application of coal. To meet with engineering requirements, we introduce a scheme of a coal sample burning point detecting instrument, which is based on an AT89C55 MCU. The characteristics, key techniques, and solutions of the temperature control system are introduced with respect to the instrument. We employ an adaptive Smith controller with a Recursive Least Squares with Exponential Forgetting (RLSEF) algorithm to solve the control problems of this time-delay, big inertia, and time-variable plant (coal sample heating furnace). Simulations show that the adaptive Smith controller is able to not only compensate the time-delay and big inertia of the plant and but also adapt to the variations of plant parameters, so that the requirement for the rising rate of temperature (5±0. 25℃min) can be fulfilled effectively.