Time-delay estimator and disturbance observer based on neural network in networked control system


  • Xuan-Kien Dang Department of Electrical and Electronic Engineering, HoChiMinh City University of Transport, Vietnam
  • Van-Thu Nguyen Department of Maritime Engineering, HoChiMinh City University of Transport, Vietnam
  • Xuan-Phuong Nguyen Department of Maritime Engineering, HoChiMinh City University of Transport, Vietnam


disturbance observer, networked control system, neural network, Smith predictor, time-delay estimator


In this paper, we deal with the control problem of network induced delays and randomly varying time-delay controlled plant under the effect of disturbances and noise in networked control systems (NCS). In a time-delay NCS it becomes more challenging to attain stability when the disturbances and noise interference appear in form of a time-varying signal in the close loop of the NCS. These in turn make the conventional control methods, e.g., normal mathematical model of Smith predictor, more complicated when the aim is to meet quality requirements of the NCS. To overcome these inherent challenges, we mainly analyze the existing techniques, and then propose a novel method to efficiently reduce the effect of time-delays, disturbances, and noise interference for highly efficient and accurate control purposes. Specifically, we introduce a joint solution of time-delay estimator and disturbance observer in which the outer loop with an adaptive Smith predictor is utilized to compensate time-delays for the whole NCS while the inner loop with disturbance observer is to eliminate the disturbances and noise interference. By using neural network identification and the estimation method, the proposed model provides many outstanding advantages such as high adaptation, robust stability, and fast response. The simulation results generated via TrueTime Beta2.0 platform demonstrate that our design significantly improves the performance of NCS.


Agarwal, M., & Canudas, C. (1987). On-line estimation of time delay and continuous-time process parameters. International Journal of Control, 46(1), 295-311. http://dx.doi.org/10.1080/00207178708933899

Anton, C., Henriksson, D., & Martin, O. (2009). TrueTime 2.0 beta 1 - Reference Manual, 1st ed. Sweden: Department of Automatic Control, Lund University.

Bahill, A. T. (1983). A simple adaptive Smith-predictor for controlling ime-delay systems. IEEE. Control System Magazine, 3(2), 16-22. DOI: 10.1109/MCS.1983.1104748

Chiang, W. L., Chen, T. W., Liu, M. Y, & Hsu, C. J. (2001). Application and robust H∞ control of PDC fuzzy controller for nonlinear systems with external disturbance. Journal of Marine Science and Technology, 9(2), 84-90. http://jmst.ntou.edu.tw/marine/9-2/84-90.pdf

Choi, Y., Yang, K., Chung, W. K., Kim, H. R., & Suh, I. H. (2003). On the robustness and performance of disturbance observers for second-order systems. IEEE Transactions on Automatic Control,48(2), 315-320. DOI: 10.1109/TAC.2002.808491

Cuenca, A., García, P., Albertos, P., & Salt, J. (2011). A non-uniform predictor-observer for a networked control system. International Journal of Control, Automation, and Systems, 9(6), 1194-1202. DOI 10.1007/s12555-011-0621-5

Cuenca, A., Salt, J. Casanova, V., & Pizá, R. (2010). An approach based on an adaptive multi-rate smith predictor and gain scheduling for a networked control system: Implementation over Profibus - DP. International Journal of Control, Automation, and Systems, 8(2), 473-481. DOI: 10.1007/s12555-010-0237-1

Dang, X. K., Guan, Z. H., Li, T., & Zhang, D. X. (2012). Joint smith predictor and neural network estimation scheme for compensating randomly varying time-delay in networked control system. Proceedings of the 24th Chinese Control and Decision Conference, China, 512-517. DOI: 10.1109/CCDC.2012.6244077

Dang, X. K., Guan, Z. H., Tran H. D., & Li, T. (2011). Fuzzy adaptive control of networked control system with unknown time-delay. Proceedings of the 30th Chinese Control Conference, China, 4622-4626. DOI: 10.1109/ICMLC.2008.4620729

Dang, X. K., Nguyen, V. T., & Nguyen, X. P. (2015). Robust control of networked control systems with randomly varying time-delays based on adaptive Smith predictor. Rangsit Journal of Arts and Sciences, 5(2), 175-186. DOI: 10.14456/rjas.2015.16

Gao, Z., & Ding, S. X. (2007). State and disturbance estimator for time-delay systems with application to fault estimation and signal compensation. IEEE Transactions on Signal Processing, 55(12), 5541-5551. Doi: 10.1109/TSP.2007.900154

Grieco, L. A., & Mascolo, S. (2002). Smith predictor and feed forward disturbance compensation for ATM congestion control. Proceedings of the 41th IEEE Conf. Decision and Control, USA, 987-992. DOI: 10.1109/CDC.2002.1184638

Huang, Y. J. ., Kuo, T. C., & Tseng, H. Y. (2007). Fuzzy estimator design for the control systems with unknown time-delay. Proceedings of the World Congress on Engineering, 417- 420.

Kato, A., Muis, A., & Ohnishi, K. (2006). Robust network motion control system based on disturbance observer. Automatika, 47(1-2), 5-10.

Kaya, I. (2003). A new Smith predictor for controlling a process with an integrator and long dead-time. ISA Transactions, 42, 101-110.

Kenji, N., & Kouhei, O. (2008). A design method of communication disturbance observer for time delay compensation, taking the dynamic property of network disturbance into account. IEEE Transactions on Industrial Electronics, 55(5), 2152-2168. DOI: 10.1109/TIE.2008.918635

Koofigar, H. R. (2014). Robust adaptive control with environmental disturbance rejection for perturbed underwater vehicles. Journal of Marine Science and Technology, 22(4), 455-462. DOI: 10.6119/JMST-013-0522-3

Lai, C. L., & Hsu, P. L. (2010). Design the remote control system with the time-delay estimator and the adaptive Smith predictor. IEEE Transactions on Industrial Informatics, 6(1), 73-80. DOI: 10.1109/TII.2009.2037917

Lee, M. H., Park, H. G., Lee, W. B., Lee, K. S., Jeong, W. B., Yoon, K. S., . . . Choi, K. K. (2012). On the design of a disturbance observer for moving target tracking of an autonomous surveillance robot. International Journal of Control, Automation, and Systems, 10(1), 117-125. DOI 10.1007/s12555-012-0113-2

Na, J., Castello, R. C. N. R., Grino, & Ren, X. M. (2009). Disturbance observer based repetitive controller for time-delay systems. Proceedings of IEEE Conference on Emerging Technologies & Factory Automation, Spain, 1-9. DOI: 10.1109/ETFA.2009.5347008

Shaltaf, S., & Abdallah, M. (2000). An enhanced technique for online discrete cosine transform based time varying delay estimation. Circuits Systems and Signal Processing, 19(6), 501-515. DOI: 10.1007/BF01271285

Shaltaf, S. J., & Mohammad, A. A. (2009). Neural networks based time-delay estimation using DCT coefficients. American Journal of Applied Sciences, 6(4), 703-708. DOI: 10.3844/ajassp.2009.703.708

Shaltaf, S. J. (2007). Neuro-fuzzy based time-delay estimation using DCT coefficients. ISA Transactions, 46(1), 21-30. DOI: 10.1016/j.isatra.2006.02.002

Shima, H., & Jo, N. H. (2009). An almost necessary and sufficient condition for robust stability of closed-loop systems with disturbance observer. Automatica, 45(1), 296-299. DOI: 10.1016/j.automatica.2008.10.009

Tran, H. D., Guan, Z. H., Dang, X. K., Cheng, X. M., & Yuan, F. S (2013). A normalized PID controller in networked control systems with varying time delays. ISA Transactions, 52(5), 592-599. DOI: 10.1016/j.isatra.2013.05.005

Yang, K. j., Choi, Y. j., Chung, W. K., Suh, I. H., & Oh, S. R. (2002). Robust tracking control of optical disk drive system using error based disturbance observer and its performance measure. Proceedings of the American Control Conference, USA, 2, 1395-1400. DOI: 10.1109/ACC.2002.1023216

Yashiro, D., & Kouhei, O. (2010). A Communication disturbance observer with a band-pass filter for delay time compensation. IEEE International Symposium on Industrial Electronics, 3585 - 3589. DOI: 10.1109/ISIE.2010.5637330

Yoo, S. J., Park, J. B., & Choi, Y. H. (2009). Adaptive dynamic surface control for disturbance attenuation of nonlinear systems, International Journal of Control, Automation, and Systems, 7(6), 882-887. DOI: 10.1007/s12555-009-0602-0

Zhao, G., & Wang, J. (2011). H∞ DOF control of stochastic systems with time-varying delay and L∞ disturbance. International Journal of Control, Automation, and Systems, 9(4), 777-784. DOI: 10.1007/s12555-011-0420-z

Zhong, Q. C., & Normey-Rico, J. E. (2001). Disturbance observer based control for processes with an integrator and long dead-time. Proceedings of the 40th IEEE Conference on Decision and Control, USA, 3, 2261-2266. DOI: 10.1109/.2001.980594




How to Cite

Xuan-Kien Dang, Van-Thu Nguyen, & Xuan-Phuong Nguyen. (2023). Time-delay estimator and disturbance observer based on neural network in networked control system. Journal of Current Science and Technology, 6(2), 173–184. Retrieved from https://ph04.tci-thaijo.org/index.php/JCST/article/view/502



Research Article