Networked Real-Time Control Strategy Dealing With Stochastic Time Delays and Packet Losses

[+] Author and Article Information
Won-jong Kim1

Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843-3123wjkim@tamu.edu

Kun Ji, Ajit Ambike

Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843-3123


Corresponding author.

J. Dyn. Sys., Meas., Control 128(3), 681-685 (Jun 21, 2005) (5 pages) doi:10.1115/1.2232692 History: Received August 18, 2004; Revised June 21, 2005

A novel model-predictive-control strategy with a timeout scheme and p-step-ahead state estimation is presented in this paper to overcome the adverse influences of stochastic time delays and packet losses encountered in network-based distributed real-time control. An open-loop unstable magnetic-levitation (maglev) test bed was constructed and employed for its experimental verification. The compensation algorithms developed in this paper deal with the network-induced stochastic time delays and packet losses in both the forward path and the feedback path simultaneously. With the p-sampling-period delay upper bound, the networked control system (NCS) can also accommodate up to p1 successive packet losses. Experimental results demonstrate the feasibility and effectiveness of this networked real-time control strategy.

Copyright © 2006 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 1

Distributed real-time control system with network-induced time delays

Grahic Jump Location
Figure 2

Actual control signal U(N) adopted by the actuator node and components of the control signal packet u(n) with respect to time when different time delays or packet losses occur. Figures (a)–(d) cover all the possible cases of the time delay τca(n) up to 4h or the number of consecutive packet losses up to 3. Short vertical lines indicate sampling instants. Solid arrows indicate that new control signal packages arrive in the corresponding sampling interval. Dotted arrows indicate that the incoming control signal packages are delayed or lost.

Grahic Jump Location
Figure 3

Ball position with packets losses beginning at t=12s

Grahic Jump Location
Figure 4

Ball position with four successive packet losses occurring every 6s

Grahic Jump Location
Figure 5

Ball position with 20% packet losses beginning at t=12s onwards

Grahic Jump Location
Figure 6

Step response without packet loss

Grahic Jump Location
Figure 7

Step response with 20% packet losses

Grahic Jump Location
Figure 8

Tracking a sinusoidal command with packet losses beginning at t=50s

Grahic Jump Location
Figure 9

System tracking response with 10% packet losses

Grahic Jump Location
Figure 10

System tracking response with 20% packet losses




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In