【正文】 有許多曲線擬合的 方法，如指數擬合，正交多項式擬合切比雪夫再恰當不過了。 該 部件 的工作狀況 制定 ，這是由作者 設計制定的 ，是旋轉擋板結構組成的輪擋板，聯軸器，爬行器齒輪和步進電機等（參見圖 1 ） 。該6024e功能數位觸發(fā)能力，以及 2 個 24位， 20 兆赫計數器 /倍 。整個系統是 具有完善的 界面，易操作，并 很好地 完成 功 能。在中國，傳統的風機性能測試是經常做手動或單片機，其中有許多不足，包括：降低精度，重型工人的勞動強度，不 完 善 的用戶界面 ，等等?？蓮V泛應用于科研院所和風機生產廠家 ,具有較高的推廣應用價值。 關鍵詞 :風機 。 因此，根據用戶的需求現代時代實 驗技術，自動測試及分析系統風機性能的基礎上的虛擬儀表工具 LabWindows / CVI 的設計在這個文件中。實驗結果表明， 穩(wěn)定性試驗過程中增加了， 讀數誤差是可以避免和測量精度和實驗效率得到了改善。和 8 數字輸入 /輸出線。 這種結構不僅可以實現自動控制， 而且 也有小而靈活 的優(yōu)點 。最小二乘法是通過以適應性能參數，因為特性曲線的風機大多是拋物線。 與這一職能的磁通整個壓力曲線， 通量靜態(tài)壓力曲線，流量 效率曲線可以達到這個數字 。 4 ）數據處理：在本 系統 中，而不是 指 原始數據，而 是 計算數據，包括流量， 效率，功率 和總壓能證明在數字和波形形式。 4 實驗系統 以離心式鼓風機（ 472型）進行全面的測試 ， 例如，在實驗室，性能測試實驗取得了該項 功能 。 performance testing。 fitting performance parameters based on least square method to draw performance curves of fans. Calculation of performance parameters Refer to the national standard GB123685[8], Aerodynamics performance test procedure of ventilator, the ventilator performance testing of the discharge outlet is achieved. The fan performance parameters are calculated as follow so: where dnis the aperture of restriction orifice。Ais the area of wind pipe。waveform display of signals, are delivered in the front panel for user operating this system conveniently. 4) Data processing: in this module, not only original data but also calculated data including flux, efficiency, power and total pressure can be shown in numeric and waveform form. Moreover, based on least square method the fan performance curve can be fitted with free selected fit module. 5) Test report: after test, operators can achieve the test report including grid or graph type of test dada in this module. Also, data saving, printing, exporting, importing etc are all realized. 6) History query: according to the test number and fan type, users can find history records they need with numeric or graph type documents in this module. Thus, a needed test report including fan performance curve can be displayed and printed. 7) Experimental simulation: a visual flash film is designed for operator to know the operating procedure well. 8) System help: using the hyper text technology, the system help on line is built which consists of three parts, namely, fan performance test system overview, background knowledge and operating instruction. In conclusion, the software system has key functions as follows: autoacquiring parameters of fan performance, adjusting the rotating speed and flux of blower, autogenerating record of testing and performance curve, moreover, the software can also display, save and print these signals in graphic and numeric form. The whole system is friendly and convenient for operating. 4 Experiment of the system Take the centrifugal blower (472 type) for testing example in laboratory, the performance testing experiment was made with this system. As shown in , each point is the numerical value of test signal, and that connected line is the performance fitting curve based on least square method. Compared with handwork which was done at the same time, the two test results are nearly equal and the accuracy can pletely meet the needs of national standard 5 Conclusion From all above, the whole system has friendly functions, which can be used widely in scientific research institutes and factories. This system improves the stability of testing process, avoids the error of reading, calculation a