本文建立一垂直液壓伺服控制系統，利用小流量伺服閥，作低速之液壓缸定位控制及追蹤控制；對於外部負載的模擬，則利用壓力伺服閥控制負載缸之油室壓力，以得到等負載或變負載之效果。
　　由於液壓伺服系統為一非線性系統，近來文獻的處理的方式，多利用操作點線性化或是系統鑑定的方法，得到一近似的線性數學模式進行控制器之設計；亦有以專家經驗為基礎，設計模糊控制器應用在此非線性系統。本文則建立一非線性數學模式，再利用非線性控制理論之輸入-輸出線性化，設計控制器並與線性控制器作比較，由實驗結果可以知道，非線性控制器應用於液壓伺服系統，其追蹤性能優於傳統線性控制器，且亦具有較佳之抗干擾能力。

The study sets up a vertical hydraulic servo control system, and controls the positioning and tracking task of the hydraulic cylinder under low speed with a small flow servo valve. For the simulation of the load force in the experiment, in order to get the result of constant or variable load force, a pressure servo valve is used, which controls the pressure of the chamber of the load cylinder.
About the nonlinearity of the hydraulic servo system, many papers in recent years used the linearization at the operation point or system identification to get the approximate linear mathematical model, and then design the controller according to the model. Also, some papers based on expert experience, applied the fuzzy controller design on this nonlinear system. This paper sets up a nonlinear mathematical model, and designs a controller using input-output linearization, then compares the results with traditional linear controller. From the observation of the experiment, the tracking performance and the disturbance rejection of nonlinear controller is better than traditional linear controller.

[1] H. E. Merritt, “Hydraulic Control Systems”, John Wiley & Sons, 1967.
[2] S. R. Lee and K. Sprinivasan, “Self-tuning Control Application to Closed-Loop Servohydraulic Material Testing”, Trans. Of ASME J. of DSMC, Vol. 112, pp. 681-689, 1990.
[3] J. S. Yun and H. S. Cho, “Application of an Adaptive Model Following Control Technique to a Hydraulic Servo Systems Subjected to Unknown Disturbances”, Trans. Of ASME J. of DSMC, Vol. 113, No.3, pp. 479-486, 1991.
[4] M. C. Shih and Y. R. Sheu, “The Adaptive Position Control of an Electro-Hydraulic Servo Cylinder”, JSME Int. J., Ser. III, Vol.34, No.3, pp. 70-376, 1991.
[5] P. C. Chen, ”An Experiment Study on the Position Control of a Hydraulic Cylinder using a Fuzzy Logic Controller”, JSME Int. J., Ser. III, Vol.34, No. 4, pp. 481-489, 1991.
[6]J.-J. E. Slontine and W. Li, “Applied Nonlinear Control”, Prentice-Hall, 1991.
[7] A. Isidori, “Nonlinear Control Systems”, Springer Verlag, Third Edition, 1996.
[8] S. Axelson and K.S.P. Kumar, “Dynamic Feedback Linearization of a Hydraulic Valve-actuator Combination”, Proceedings of the American Control Conference, Vol. 88, pt 1-3, pp. 2202-2203,1988.
[9] H. Hahn, A. Piepenbrink, and K.-D. Leimbach, “Input/Output Linearization Control of an Electro Servo-Hydraulic Actuator”, IEEE Conference on Control Applications - Proceeding, Vol. 2, pp. 995-1000, 1994.
[10] J. Chiriboga, M.-W. L. Thein, and E. A. Misawa, “Input-output Feedback Linearization Control of a Load-sensing Hydraulic Servo System”, IEEE Conference on Control Applications - Proceeding, pp. 910-915, 1995.
[11] G. Vossoughi and M. Donath, “Dynamic Feedback Linearization for Electrohydraulically Actuated Control Systems”, ASME Journal of Dynamic Systems, Measurement and Control, Vol. 117, pp. 468-477, 1995.
[12] M. Lemmen and M. Bröcker, “CACSD for hydraulic cylinders”, Proc. Of the 2000 IEEE International Symposium on Compter-aided Control System Design, pp 101-106, 2000.
[13] G. A. Sohl and J. E. Bobrow, “Experiments and Simulation on the Nonlinear Control of a Hydraulic Servosystem”, IEEE Transations Control Systems Technology, Vol. 7, No.2, pp. 238-247, 1999.
[14] A. Kugi, K. Schlacher, and R. Novak, “Nonlinear Control in Rolling Mills: A New Perspective”, IEEE Transations on Industry Applications, Vol. 37, No. 5, pp. 1394-1402, 2001.
[15] R. H. Brown, S. C. Schneider, and G. M. Mulligan, “Analysis of Algorithms for Velocity Estimation from Discrete Position Versus Time Data”, IEEE Transations On Industrial Eletronics, Vol. 39, No. 1, pp. 11-19, 1992.
[16] NAKAMURA, “Applied Numerical Methods in C,” Prentice Hall, Internation Editions, 1995.
[17] A. Tustin, “The Effects of Backlash and of Speed-Dependent Friction on the Stability of Closed-Cycle Control System,”J. of the Institution of Electrical Engineers, Vol. 94, No.2, pp. 143-151, 1947.
[18] 許朝勝, ”長行程單桿液壓缸於垂直負荷之位置伺服控制研究”,成大機械所論文,1999.
[19] 許耀林, “H∞控制理論應用於材料試驗機力控制之研究”,台大造船及海洋工程學研究所, 2001.
[20] 邱奕範, “命令及摩擦力前饋控制於工具機之研究,” 成功大學機械研究所論文, 2002.
[21] 李義評, ”模糊控制塑膠射出成型機射出速度及保壓之研究”,成大機械所論文,1996.