恒温箱温度控制系统的设计

摘要

在此次设计中，主要是设计一套能够精确控制温度的恒温箱温度控制系统。该系统能够实时、自动、准确的测量恒温箱内的温度，然后通过加热和降温将温度控制在设定的误差范围内。恒温箱在各个领域里都有很重要的意义，但其控制系统又较为复杂，基本上不可能用数学的方法建立准确的模型。当前是用经典控制和智能控制两种控制算法相结合的方式对温度进行高效的控制。

我们采用STC12C5A60S2单片机作为核心控制器，温度测量采用数字温度传感器，使用PID控制，输出控制用量的调节用的是可控硅触发端的通断，从而实现对温度的控制。温度在一定范围内可以由人工调节，并能在环境温度降低时实现自动调整。这样将PID和单片机结合使用，可以将整个控制系统的精度提高，将误差减小。

PID算法是经典的控制算法，在实际的控制中有着很高的地位。PID算法相对简单，控制精度高。但是PID调节的参数无法适应系统很长时间，需要对参数不断的整定，以达到更好的控制效果。该算法最重要的是怎样合理有效的整定其参数，针对这种情况我们就要对其进行仿真建模，通过MATLAB找到更好的解决方法，以免浪费不必要的时间，有效的提高了设计效率，也使控制性能可以达到预期的效果。

关键词：恒温箱；温度控制；MATLAB；PID

This paper is mainly to design a set of temperature control system that can control the temperature of incubators precisely. This system is capable in automatically and accurately measuring the temperature inside the oven in real-time and control the temperature within the setting error range by heating and cooling. Incubators have a very important significance in various fields. Due to its complication in the control system, basically it is impossible to mathematically establish a mode accurately. The current used algorithm control method is the classical control method and intelligent control method. By combining these two algorithms, an effective control on the temperature is achieved.

STC12C5A60S2 microcontroller is used as the core controller. The temperature measurement is done by using PID control on the digital temperature sensor. The amount of output is control by using the trigger of SCR, where the temperature control is achieved. The temperature can be adjusted manually within certain range and it can adjust automatically when the ambient temperature decreases. The combination of usage of PID and microcontroller can increase the accuracy of the control system and therefore reduce the errors.

PID is a classical algorithm and control algorithms. It has a very high status in the actual control system. The PID algorithm is relatively simple and has high precision of control. But in order to achieve a better control effect, The PID parameters need a constant tuning and they are unable to adapt in the system for a longer time. Therefore is it important for finding a reasonable and effective tuning for the parameters in which we have to modeling and stimulation. In order to find a better solution without wasting much time, MATLAB is used and this has effectively improve the design efficiency and the control performance achieved the desired results.

Key words: Incubators; Temperature control; MATLAB; PID control

摘要 .................................................................................................................... I Abstract................................................................................................................. II 引言 .. (1)

1 绪论 (2)

1.1 课题背景，目的和意义 (2)

1.2 国内外研究现状 (2)

1.3 发展方向 (3)

1.4 本章小结 (3)

2 恒温箱温度控制系统的总体设计 (4)

2.1 恒温箱温度控制系统设计的研究内容与基本要求 (4)

2.1.1恒温箱温度控制系统设计的研究内容 (4)

2.1.2恒温箱温度控制系统设计的基本要求 (4)

2.2 恒温箱温度控制系统的基本工作原理 (4)

2.3 控制方案的选择 (5)

2.3.1比例控制（P） (5)

2.3.2比例积分控制（PI） (6)

2.3.3比例微分控制（PD） (6)

2.3.4比例积分微分控制（PID） (7)

2.4 PID的特点与参数的整定 (8)

2.4.1PID调节器的特点 (8)

2.4.2PID调节器参数的整定 (8)

2.5 本章小结 (9)

3 恒温箱温度控制系统的硬件电路的设计 (10)

3.1 元器件的选择 (10)

3.1.1温度传感器的选择 (10)

3.1.2电线的选择 (10)

3.1.3显示器的选择 (11)

3.1.4 稳压器的选择 (11)

3.1.5按键的选择 (12)

3.1.6加热负载控制器件的选择 (12)

3.1.7核心控制器的选择 (13)

3.2 单片机电路的设计 (13)

3.3 显示电路的设计 (14)

3.4 按键电路的设计 (15)

3.5 报警电路的设计 (16)

3.6 稳压电路的设计 (16)

3.7 过零检测电路 (17)