Mehmet Önder EFE, Coşku KASNAKOĞLU

A nonlinear disturbance observer scheme for discrete time control systems

This paper presents a modification to the original disturbance observer based control (DOBC) scheme by redefining the lowpass filter using a nonlinear element. The proposed technique improves the disturbance prediction performance for both small and large magnitude disturbance signals. The contribution of the current work is to unfold the stability and performance conditions under the proposed modification. A comparative set of simulation studies are discussed and it is seen that the proposed modification results in smaller disturbance prediction error energy and smaller tracking error energy when the plant model is discrete time and uncertain.

PDF

___

[1] Gürhanlı A. Modified acceleration feedback for practical disturbance rejection in motor drives. Turkish Journal of Electrical Engineering & Computer Sciences 2018; 26: 2151-2161.
[2] Vatankhah B, Farrokhi M. Offset-free adaptive nonlinear model predictive control with disturbance observer for DC-DC buck converters. Turkish Journal of Electrical Engineering & Computer Sciences 2017; 25: 2195-2206.
[3] Zeinaly Z, Ramezani A, Ozgoli S. Design and implementation of a modified communication disturbance observer for teleoperation systems. Turkish Journal of Electrical Engineering & Computer Sciences 2017; 25: 1522-1540.
[4] Ohishi K, Ohnishi K, Miyachi K. Torque-speed regulation of dc motor based on load torque estimation method. In: Proceedings of the JIEE International Power Electronics Conference; Tokyo, Japan; 1983. pp. 1209-1218.
[5] Chen WH, Yang J, Guo L, Li S. Disturbance-observer-based control and related methods-an overview. IEEE Transactions on Industrial Electronics 2016; 63 (2): 1083-1095.
[6] Sarıyıldız E, Oboe R, Ohnishi K. Disturbance observer-based robust control and its applications: 35th anniversary overview. IEEE Transactions on Industrial Electronics 2019; 67 (3): 2042-2053.
[7] Kempf CJ, Kobayashi S. Discrete-time disturbance observer design for systems with delay. In: Proceedings of 4th IEEE International Workshop on Advanced Motion Control; Mie, Japan; 1996. pp. 332-337.
[8] Godler I, Honda H, Ohnishi K. Design guidelines for disturbance observer’s filter in discrete time. In: Proceedings of 7th IEEE International Workshop on Advanced Motion Control; Maribor, Slovenia; 2002. pp. 390-395.
[9] Yang K, Choi Y, Chung WK. Performance analysis of discrete-time disturbance observer for second-order systems. In: Proceedings of the 42nd IEEE Conference on Decision and Control; Maui, Hawaii, USA; 2003. pp. 4877-4882
[10] Chen C, Tomizuka M. Optimal plant shaping for high bandwidth disturbance rejection in discrete disturbance observers. In: American Control Conference; Baltimore, MD, USA; 2010. pp. 2641-2646
11] Lee C, Joo Y, Shim H. Analysis of discrete-time disturbance observer and a new q-filter design using delay function. In: 12th International Conference on Control, Automation and Systems; Jeju Island, Korea; 2012. pp. 556-561.
[12] Kang D. Design of a disturbance observer for discrete-time linear systems. In: 14th International Conference on Control, Automation and Systems; Gyeonggi-do, Korea; 2014. pp. 1381-1383.
[13] Park G. Joo Y, Lee C, Shim H. On robust stability of disturbance observer for sampled-data systems under fast sampling: an almost necessary and suﬀicient condition. In: IEEE 54th Annual Conference on Decision and Control; Osaka, Japan; 2015. pp. 7536-7541.
[14] Shim H, Jo NH. An almost necessary and suﬀicient condition for robust stability of closed-loop systems with disturbance observer. Automatica 2009; 45 (1): 296-299.
[15] Yun H, Park G, Shim H, Chang HJ. State-space analysis of discrete-time disturbance observer for sampled-data control systems. In: American Control Conference; Boston, MA, USA; 2016. pp. 4233-4238.
[16] Uzunovic T, Sariyildiz E, Sabanovic A. A discussion on discrete implementation of disturbance-observer-based control. In: IEEE 15th International Workshop on Advanced Motion Control; Tokyo, Japan 2018. pp. 613-618.
[17] Muramatsu H, Katsura S. An adaptive periodic-disturbance observer for periodic-disturbance suppression. IEEE Transactions on Industrial Informatics 2018; 14 (10): 4446-4456