多机测控系统在风洞试验研究中的应用

THE APPLICATION OF MULTI-COMPUTER MEASUREMENT AND CONTROL SYSTEM IN THE WIND TUNNEL EXPERIMENTAL RESEARCH

一种多计算机数据自动采集、处理和控制系统成功地应用于大迎角气动特性研究的风洞试验中,实现了大迎角非对称裁荷的主动控制和数据处理。系统主要由硬、软件两部分组成。硬件包括:中心计算机、控制机、A/D 转换器、接口等;软件包括:数据采集、处理、控制及其算法等程序。其中主动控制部分能满足目标函数的控制要求。且干扰、误动作影响小,工作可靠性强。具有适应范围广、实现容易、成本低等特点,为测控技术多机网络实现计算机风洞测控技术应用积累了实践经验,给风洞-计算机一体化的研究提供了技术资料。

A multi-computer measurement and control system andits application in a wind tunnel experimental research are introducedin this paper.The signals are detected by sensors.Then they are filteredamplified,and fed to the A/D converters,which convert them to digital variables and feed into the central computer.The central computer cutsoff the errors and supplies filter to produce a signal for control.Then,central computer feeds the data in according with given algorithm toproduce control signals.The signals from control computer are fed tothe executive components to operation.Two control approaches:Look-up control and adaptive control areadopted in the system.The look-up control is that experimental dataobtained by manual experiments are stored in the control computer.The computer compares the data in it with the data sampled and deter-mines control values.The data are used as PID adjustment variables.Finally the control computer calculates final control value.For theadaptive control method,the computer continually samples the plantoutput signals,and automatically determines the system states andcorrects the system operations to ensure the system in an optimum statein accordance with minimum value principle and dynamic programmingprinciple.The system software are compiled with assembly and advancedlanguage,Sampling,control and communication programs are compiledwith assembly language.The data processing programs compiled withadvanced language. In calculating methods, the mathematical expectationof the multi-point sampling values are obtained. DDC increamentadjustment algorithm, which is one of the PID algorithm, is adopted.The control system has been applied successfully in wind tunnelexperimental researches about areodynamics characteristic control athigh angles of attack. The results show that the system has satisfiedwith the control accuracy requirements. It is of the small effect ofinterference and a little error operations, well steady and reliableoperation, simple construction, low costs and broad application ranges.