1、2850英文单词，1.4万英文字符，中文4900字外文翻译原文 Teaching digital control using a low-cost microcontroller-based temperature control kit Abstract The design of a low-cost digital temperature control kit is described. The system enables the students to implement various control strategies using a microco
2、ntroller. The kit is intended to be helpful in a control laboratory as a complement to the digital control system theory taught to undergraduate students. Keywords microcontroller-based control； teaching digital control； temperature control With the availability of low-cost computers a
3、nd microcontrollers, digital control has gained popularity and most current control systems are based on digital techniques. The same is true for simulation. Digital simulation techniques have replaced analogue simulators. These simulators are in the form of interactive computer packages used in the
4、 industry, in research laboratories, colleges and universities. Early simulation packages such as ACSL were designed for large mainframe computers and only large organizations could afford to purchase and use such packages. Currently, software packages such as TUTSIM, 20-sim, program CC, VisSim, Ext
5、end, and MATLAB are available for desktop PCs and they are within the budgets of most universities and colleges. Some packages (e.g. MATLAB and program CC) are also offered in the form of a low-cost student edition and students can purchase and use these packages on their own PCs, away from the univ
6、ersity laboratories. Simulation is an invaluable tool in teaching the theory of control system. For example, the student can plot the accurate root-locus of a complex System in a matter of a few minutes rather than spending several hours. Similarly, the time and frequency responds of a system can ve
7、ry easily be plotted with the aid of simulator package. Although the simulators are very useful tools they are not same as real world solutions. There are also cases in which computer models may be inappropriate, or the system is too complex to describe by mathematical equations in a computer. It is
8、 the authors experience that students learn an engineering topic best when they see the physical results of the experiments they perform. Simulation can still be used at the first level of the analysis but this should be supported with real physical laboratory experiments. Thus, simulators should be
9、 a complementary tool rather than the only tool when teaching an engineering topic. One of the problems with commercially available physical laboratory experiments is that the experimental kits are usually very expensive, especially when a number of similar kits are purchased for teaching purpose. S
10、uch kits may also require frequent calibration and maintenance services as a result of component failures and ageing. Laboratory kits also do become obsolete quite rapidly as new products are developed. This paper describes a low-cost temperature control kit which is designed and used in the enginee
11、ring teaching laboratories of Near East University. The kit is based on the popular PIC16F877 model microcontroller, manufactured by Microchip Inc. The overall cost of the kit is less than $200, which is well below the cost of similar commercially available educational temperature control kits. The
12、design, modeling and digital control of the kit are described in detail. Temperature control kit Educational temperature control kits are not new. Many companies manufacturing laboratory kits also offer some kind of general process control or temperature control kits.TCL-1 by Kuruganti is a temperat
13、ure control loop trainer which is intended to show how the temperature in a heat exchanger can be controlled. TCL-1, also by Kuruganti, is an on/off-based temperature control teaching kit. PROCON by Feedback Instruments is a progress control system, which includes rigs for level, flow, temperature a
14、nd pH control. Here, the temperature control system uses water as the process fluid and the kid provide PID control with auto-tune facilities. G34/EV is a PID-based educational temperature control unit manufactured by Elettronica. The unit can be interfaced to a PC and consists of a PID controller,
15、power amplifier, and signal conditioner for temperature sensors. Near East University offers undergraduate and graduate level engineering courses and control engineering is one of these topics, which is taught for one semester. There are no practical experiments and students have been using the MATL
16、AB package to design, simulate and test their control theory. It was felt necessary to provide some practical experiments to the students as a way of supporting the theoretical concepts taught in the classroom. The main reason to design a control kit rather than to buy a commercially available one w
17、as the cost. Process control is a very important field of automatic control engineering and as a first initiative it was decided to develop a digital temperature control experiment based upon a microcontroller. One of the aims during the implantation of this laboratory kit was to use low cost, but i
18、ndustrial equipment in order to ensure the necessary robustness for its use. It is hoped to develop more control-based experiments in the near future with the participation of members of the faculty and students. The block diagram of the digital temperature control kit is shown in Fig.1. The working
19、 principle of this experiment consists of heating the water in a small container using a low-voltage electric heating element and a simple MOSFET-based power controller circuit. A temperature sensor is immersed into the water whose output signal is sent to a PIC-type microcontroller. This signal is compared with a reference temperature signal and a PID controller algorithm is implemented by the microcontroller to achieve the required temperature control action.
