• 沒有找到結果。

6.1 結論

在本論文提出的圖 2-6 的架構中,在控制器的部分,先利用圖 3-1 所示之解耦合的 方式得到兩個單輸入單輸出的系統,H控制器設計方法於圖 3-2 中實現,使其車輛在對 抗外擾時有不錯的穩健性,並且使車輛的動態特性能與參考訊號吻合。藉甫(22)式參考 模型的設計,除了可以使車輛的性能在暫態及動態受到控制外,且其內參數選擇度高並 不會受限於車體本身的參數。在另一方面,若經甫最佳化設計出一個參考模型,則可以 透過本論文提出的架構,無論後端的控制器用何種控制理論去設計只要能使車輛的動態 特性能與參考訊號相同,在物理條件的許可情況下就可以應用在不同的車輛上達到模組 化的目的。

於實驗中H Output Tracking Control 需要側滑角回授資訊,甫於側滑角是用估測出 來的,因此在進入參考模型的驗證前將實驗先分為兩個部分:第一個部分為只開啟橫擺 角速度的控制迴路且令橫擺角速度的參考訊號為零,而第二部分將兩個控制迴路都打開 且側滑角以及橫擺角速度的參考訊號令為零。在第一部分的實驗一裡,甫於橫擺角速度 有儀器做量測,所以控制效果不錯,甫於控制迴路的解偶合,因此可以驗證圖 2-6 的架 構的可行性。於第二部分的實驗二以及在最後將參考模型加入的實驗三裡可以知道,雖 然實際訊號有追隨參考訊號的趨勢,但側滑角估測的精確度不足,加上甫系統識別得到 之側向加速度、橫擺角速度的轉移函數所推出之側滑角轉移函數存在誤差,因此使實驗 產生誤差。且在路徑軌跡的驗證部分,缺乏儀器去作驗證,故只能採取積分的方式去做 驗證,有存在誤差的可能性。

利用模型車進行先期實驗,可降低實車測試所需之成本,並做為快速原型開發之基 礎,同時研究將著重在車輛參考模型於緊急狀況下的探討,使車輛在緊急狀況發生時,

能夠有更好的緊急避障功用。

6.2 未來展望

在模擬方面,本篇論文所提出的控制架構可以得到不錯之結果,未來可甫以下方面 持續改善效能,但是推導的過程中採用為線性模型簡化參數過多因此沒有考慮到物理條 件範圍的討論,未來將考慮更複雜之車輛模型並且探討控制器之容忍範圍。

為了推導的簡易性,所利用之汽車模型是在縱向速度固定的情況下,使系統呈現出 線性非時變(LTI)的特性。未來將考慮縱向速度為時變以及輪胎參數為非線性關係之接近 真實性質的 Magic Formula 輪胎模型去進行車輛性質分析及設計控制器。

在參考模型方面,未來將輸出資料回授給參考模型,並將考慮用更簡單的方法利用 (22)式的關係去操縱車輛,例如只改變質量使其為時變,使汽車在過彎時能像質量小的 汽車一樣靈活,走直線時能夠向質量重的汽車一樣利用慣性大的特性去對抗外擾。

本文實驗所使用的參考模型為較簡易的,未來可利用較複雜之參考模型結合駕駛人 輸入命令,在精確度更高的實驗帄台做驗證,可利用具有數位訊號輸出的陀螺儀與加速 規,一方面提高量測精確度,一方面避免轉換感測器讀數時的直流偏移。利用精度較高 的感測器,進行模型參數估測的結果亦會較為準確,可降低系統不確定性,提高控制效 能,並根據不同的行車情形來決定橫擺角度與側向加速度之參考訊號,使四輪轉向車輛 發揮更大效能,提高駕駛人的安全性與舒適性。

參考資料

[1] Jang, S., Park, T., & Han, C., “A CONTROL OF VEHICLE USING STEER-BY-WIRE SYSTEM WITH HARDWARE-IN-THE-LOOP-SIMULATION SYSTEM”, Proceeding of the IEEE/ASME International Conference on Advanced Intelligent Mechatronics, pp.

389-394, South Korea, July 2003.

[2] Ackermann, J., “ROBUST DECOUPLING, IDEAL STEERING DYNAMICS AND YAW STABILIZATION OF 4WS CARS”, AUTOMATICA, Vol. 30, No 11, pp. 1761-1768, 1994.

[3] Marino, R., & Cinili, F., “INPUT-OUTPUT DECOUPLING CONTROL BY MEASUREMENT FEEDBACK IN FOUR-WHEEL-ACTIVE-STEERING VEHICLES”, Proceedings of the 45th IEEE Conference on Decision & Control, San Diego, CA, USA, Dec. 13-15, 2006.

[4] Irie, N., & Kuroki, J., “4WS TECHNOLOGY AND THE PROSPECTS FOR IMPROVEMENT OF VEHICLE DYNAMICS”, SAE transactions, Vol. 99, No. 6, pp.

1334-1342, 1990.

[5] Miguel A. Vilaplana et al., “CONTROL OF SIDESLIP AND YAW RATE IN CARS EQUIPPED WITH 4-WHEEL STEER-BY-WIRE”, SAE transactions, Vol. 113, No 6, pp.

1082-1094, 2004.

[6] Miguel A. Vilaplana et al., “CONTROL OF YAW RATE AND SIDESLIP IN 4-WHEEL STEERING CARS WITH ACTUATOR CONSTRAINTS”, R. Murray-Smith, R. Shorten (Eds.): Switching and Learning, LNCS 3355, pp. 201-222, 2005.

[7] Raksincharoensak, P., Mouri, H., & Nagai, M., “EVALUATION OF FOUR-WHEEL-STEERING SYSTEM FROM THE VIEWPOINT OF LANE-KEEPING CONTROL”, International Journal of Automotive Technology, Vol. 5, No. 2, pp. 69-76,

2004.

[8] TMS320F2812 DIGITAL SIGNAL PROCESSOR DATA MANUAL, Texas Instruments Ins., 2006.

[9] eZdspTM F2812 TECHNICAL REFERENCE, Spectrum Digital Inc., 2002.

[10] CODE COMPOSER STUDIO V3. 1 IDE GETTING STARTED GUIDE, Texas Instruments Inc., 2004.

[11] Ljung, L., SYSTEM IDENTIFICATION: THEORY FOR THE USER, Prentice Hall Inc., Englewood Cliffs, New Jersey, 1987.

[12] Juang, J., APPLIED SYSTEM IDENTIFICATION, PTR Prentice Hall Inc.,Englewood Cliffs, New Jersey, 1994.

[13] Wang B. et al., “INFLUENCE OF DRIVER'S REACTION TIME AND GAIN ON DRIVER-VEHICLE SYSTEM PERFORMANCE WITH REAR WHEEL STEERING CONTROL SYSTEMS: PART OF A STUDY ON VEHICLE CONTROL SUITABLE FOR THE AGED DRIVER”, JSAE Review, pp. 75-82, 2002.

[14] Iwasaki, T., & Skelton, R. E., “ALL CONTROLLERS FOR THE GENERAL H INFINITY CONTROL PROBLEM: LMI EXISTENCE CONDITIONS AND STATE SPACE FORMULAS”, Automatica, Vol.30, No. 8, pp.1307-1317, 1994.

[15] Geng, C., Mostefai, L., & Hori, Y., “A HYBRID-LIKE OBSERVER OF BODY SLIP ANGLE FOR ELECTRIC VEHICLE STABILITY CONTROL: FUZZY LOGIC AND KALMAN FILTER APPROACH”, Proceedings of the 34th IEEE Conference on Industrial Electronics, pp. 108-113, Tokyo, Nov. 10-13, 2008.

[16] Piyabongkarn, R. Rajamani, J. Grogg, et al., “DEVELOPMENT AND EXPERIMENTAL EVALUATION OF A SLIP ANGLE ESTIMATOR FOR VEHICLE STABILITY CONTROL”, IEEE Transactions on Control Systems Technology, vol. 17, pp. 78-88, 2009.

[17] B. Francis, “ON OPTIMAL SENSITIVITY THEORY FOR SISO FEEDBACK SYSTEMS” Proceedings of the IEEE Conference on Decision & Control, including the Symposium on Adaptive Processes vol. 21, 1982.

[18] Rajamani, R., VEHICLE DYNAMICS AND CONTROL: Springer, 2006.

[19] Lin, Y.,“IMPROVING VEHICLE HANDLING PERFORMANCE BY A CLOSED-LOOP 4WS DRIVING CONTROLLER,” SAE921604, pp.1447~1457 ,1992.

[20] Whitehead, John C., “FOUR WHEEL STEERING: MANEUVERABILITY AND HIGH SPEED STABILIZATION,” SAE Paper 880642, pp. 688-679, 1988.

[21] Siahkalroudi VN, Naraghi M. “MODEL REFERENCE TRACKING CONTROL OF A 4WS VEHICLE USING SINGLE AND DUAL STEERING STRATEGIES. ” SAE 2002-01-1590, 2002.

[22] G. Bishop and G. Welch. “ An Introduction To The Kalman Filter. ”SIGGRAPH 2001 Course Notes, 2001.

[23] 林毅泓,蕭得聖. “四輪轉向實驗車輛的建構與控制之研究”.國立交通大學,2007

[24] Nikzad SV, Naraghi M. “OPTIMIZING VEHICLE RESPONSE IN A COMBINED RIDE AND HANDLING FULL CAR MODEL BY OPTIMAL CONTROL STRATEGIES. ” SAE 2001-01-1581, 2001.

[25] Song, J., & Boo, K.. “PERFORMANCE EVALUATION OF TRACTION CONTROL SYSTEMS USING A VEHICLE DYNAMIC MODEL. ”Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 218(7), 685-695, 2004.

[26] Eguchi, T., Sakita, Y., Kawagoe, K., Kaneko, S., Mori, K., and Matsumoto, T.,

“DEVELOPMENT OF „SUPER HICAS‟, A NEW REAR WHEEL STEERING SYSTEM WITH PHASEREVERSAL CONTROL,” SAE paper 891978, pp. 1495-1504, 1989.

[27] Song, J., & Yoon, Y. “FEEDBACK CONTROL OF FOUR-WHEEL STEERING USING TIME DELAY CONTROL.” International Journal of Vehicle Design, 19(3), 282-298,1998.

[28] Furukawa, Y., Yuhara, N., Sano, S., Takeda, H., & MATSUSHITA, Y. “ A REVIEW OF FOUR-WHEEL STEERING STUDIES FROM THE VIEWPOINT OF VEHICLE DYNAMICS AND CONTROL. ” Vehicle System Dynamics, 18(1), 151-186, 1989.

[29] Winkler, C. “SIMPLIFIED ANALYSIS OF THE STEADY-STATE TURNING OF COMPLEX VEHICLES. ”Vehicle System Dynamics, 29(3), 141-180,1998.

相關文件