【作者】 申明会；

【导师】 赵曜；

【作者基本信息】 四川大学 ， 控制理论与控制工程， 2006， 硕士

【摘要】 大多数传感器的输出(通常是微弱的电压或电流信号)和被检测的信号之间为非线性关系。气体流量传感器也是如此，因而在每一个流量计出厂前必须对它标定。标定的一种方法是：给出流量计量程范围内的若干个流量作为测试点(下面简称测点)，记录对应每一个测点的传感器的输出，再分段线性化，就得到了量程范围内的一张流量&传感器输出表——标定表；当使用这个流量计测量流量时，流量计根据内部的传感器输出查标定表就得到了此时的流量。我所做的工作就是通过调整步进电机和变频器在气体管道上给出一个测点流量。 在本次设计以前，对每一个测点的调节是由操作人员观察标准气体流量表(以下简称标准表)的读数，然后手动调整变频器和步进电机来实现的。变频器控制管道风速，步进电机驱动器控制阀门大小，以此来决定管道的气体流量。但人工操作的主要缺点就是速度慢，生产效率低。为此，本人设计了基于ATmega16单片机的气体流量控制器。它可以接收测点的输入，然后读取标准表获取实际的流量，根据实际流量和目标流量(测点流量)之间的偏差调整变频器的输出频率和步进电机的步数，最终使气体管道的流量达到测点流量。 流量控制器的核心是单片机，它直接关系到控制器设计的可靠性、复杂性以及开发周期。选用ATmega16单片机具有很多好处。它具备1 MIPS／MHz(百万条指令每秒／兆赫兹)的高速处理能力，并具有强大的片内外设。因此，本系统虽然只进行了较少的外围电路设计却能够实现复杂的系统功能，包括变频器的数字PID控制、步进电机驱动器的控制、三个LED的显示、四个按键的输入扫描、同PC的RS232通信等。此外，ATmega16单片机更适宜用高级语言编程，从而能够大大缩短软件的开发周期。本次设计采用了ImageCraft公司的ICCAVR C语言编译器。在软件设计上，采用了时间触发嵌入式系统设计模式。先更多还原

【Abstract】 The outputs of most sensors which are generally small voltage or current signals are nonlinear with the tested signals. So is the flow sensor in a gas flowmeter. We must scale the flowmeter before we use it. Here’s a way of scaling a flowmeter. Firstly, we need to pick several flowrate samples among the range of the flowmeter to implement them one by one on the scaling platform; secondly, we record the corresponding voltage outputs of the flowmeter; finally, we make the piece-wise linearization to the outputs of the flowmeter based on its whole range and get a Flow-Voltage table, the scaling table. If we carry out a flow measurement with the flowmeter, the flowmeter will look up the scaling table according to its voltage output and get the flowrate magnitude. My work is the implementation of the selected flowrate in the air pipeline of the scaling platform through the adjustment of stepping motor and frequency-converter.The task used to be done by an operator before this design was accomplished. The operator uses the stepping motor to tune the valve and the frequency-converter to control the air speed in the pipeline so that he can adjust the flowrate to his destined magnitude. But there are some weaknesses in this scaling mode that the adjusting time is unbearable long and it takes the operator to do the repeated job if we need scale many flowmeters of the same type. So I designed a gas flowrate controller based on ATmegal6, a microcontroller produced by ATMEL co. of U.S.A. The controller can accept the flowrate inputs set by an operator, and then read the standard flowrate that could measure the current flowrate in a high degree of更多还原