外文翻译---基于stm32的恒温箱温度控制系统

外文翻译---基于stm32的恒温箱温度控制系统内容摘要：

nd program, and an extensive range of enhanced I/Os, most of which have alternate functions and peripherals connected to two APB buses. It has three general purpose 16bit timers plus two watchdogs, as well as standard and advanced munication interface USART used to municate with LCD[2]. More importantly, it offers two 12bit ADCs with 1μ s conversion speed which make it suit for fast acquisition and fast processing. It is one of the important reasons for this system to choose TM32F103 as the core controller. Filtering and conversion circuits In order to realize the convention from PWM signal to analog output, we use the second order low pass filter to filter out the high frequency ponents and keep DC ponent and changing duty cycle of PWM signal so that the analog voltage output is got then. shows the designed Butterworth filter. After filtering, convert PWM signal to 0~ V to control thyristor conduction angle[3]. Thus we realized the precise control of heating temperature. Fig 3 Butterworth filter 4 Software design control algorithm This system uses PID control algorithm which is a basic control method widely used in industrial process control method widely used in industrial process control. Augmented PID control algorithm[4] is uk uk 1 = KP ( ek ek 1 ) + K 1 ek + K D ( ek 2ek 1 + ek 2 ) . However, if this algorithm was used directly, it could generate a lare overshoot and cause integral saturation easily when starup, stop or adjust substantially. In order to inhibit the emergence of this phenomenon, we use integral separation as an improvement. Integral separation won39。 t work until actual temperature is approaching the settings. When it works, it can eliminate static error and improve precision[5]. Block diagram of integral separation PID is shown in . Fig 4 Integral separate PID algorithm block diagram Touch screen software design It makes humanputer interface much more friendly, more convenient and faster by using touch screen. Use dedicated control chip ADS7843 to connect AMT9532, fourwire resistive touch screen, withSTM32F103, process the touch screen signals[6]. Touch screen39。 s software design flow chart is shown in . Fig 5 Touch screen flow chart Use standard thermometer with ℃ precision as calibration to check the experimental results. Specific methods: set different temperatures within the appropriate range though touch screen, wait until the temperatures shown in the LCD are stable, then calculate the errors based on the actual temperature of standard thermometer with fo。