To apply the network QoS (Quality-of-Service) concept including as Integrated Service (Int-Serv) and Differentiated Service (Diff-Serv) to effectively support end-to-end networked control applications.

Main focuses are: How network QoS such as bandwidth, jitter, loss rate affect performances of a networked control system.

• How to systematically find or mathematically approximate the mapping between application QoS/control performance specification and network QoS.
• How to design an optimal QoS profile to support a networked control system.
• How to adapt a networked control system to compensate changes in QoS or deterioration in QoS.

Distributed mobile robots operated over a network as shown in Figure 1 is used as our case study. The network in this project is assumed to be shared with other applications such as email, FTP, MP3 video stream, etc.

Fig. 1 Distributed mobile robot system.

Journal Papers

• M.-Y. Chow, Y. Tipsuwan, “Gain Adaptation of Networked Dc Motor Controllers on QoS Variations,” IEEE Transactions on Industrial Electronics, Vol. 50, no. 5, October, 2003.
• Y. Tipsuwan and M.-Y. Chow, "Control Methodologies in Networked Control Systems," Control Engineering Practice, vol. 11, 2003, pp.1099-1111.

Conference Papers

• Y. Tipsuwan, M.-Y Chow, “Neural Network Middleware for Model Predictive Path Tracking of Networked Mobile Robot over IP Network,” IEEE IECon’03, Roanoke, VA, Nov 2 – Nov 6, 2003.
• Y. Tipsuwan, M.-Y. Chow, “An Implementation of a Networked PI Controller over IP Network,” IEEE IECon’03, Roanoke, VA, Nov 2 – Nov 6, 2003.
• Y. Tipsuwan, M.-Y. Chow, “On the Gain Scheduling for Networked PI Controller Over IP Network,” 2003 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Port Island, Kobe, Japan, July 20-24, 2003.
• Y. Tipsuwan, M.-Y. Chow, “Gain adaptation of mobile robot for compensating QoS deterioration”, Proceedings of IECon’02, Sevilla, Spain, November 5 – 8, 2002.
• Y. Tipsuwan, M.-Y. Chow, “Network-Based Controller Adaptation Based On QoS Negotiation and Deterioration,” IECon01, Denver, CO, Nov.28-Dec.02, 2001, pp. 1794 -1799.
• M.-Y. Chow, Y. Tipsuwan, “Network-based control adaptation for network QoS variation,” MILCOM 2001, October 28-31, 2001, McLean, VA, pp. 257-261.

Thesis and Technical Reports

• Y. Tipsuwan, Gain Scheduling for Networked Control System, Ph.D. Thesis, Department of Electrical and Computer Engineering, North Carolina State University, August 2003.
• Y. Tipsuwan, Network-based control systems: Qualifying review report, Department of Electrical and Computer Engineering, North Carolina State University, October 2001.

Tutorials

• M.-Y. Chow, “Methodologies in Time Sensitive Network-Based Control Systems,” 2003 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Port Island, Kobe, Japan, July 20-24, 2003.
• M.-Y. Chow, Y. Tipsuwan, “Real Time Network-Based Control System,” IEEE IECon 2002 Tutorial, Sevilla, Spain, November 5, 2002.
• M.-Y. Chow, Y. Tipsuwan, “Network-Based Control Systems: A Tutorial,” Proceedings of IEEE IECon 2001 Tutorial, November 28 – December 2, Denver, CO, pp. 1593 -1602.

Software prototype:

The distributed mobile robots operated over network with different QoS settings is simulated on Matlab/Simulink platform. The simulation focuses on two types of Quality-of-Services

• Integrated Service: This type of QoS allows each mobile robot system to reserve network resources for guaranteed QoS such as bandwidth, delay bound, and loss rate.
• Differentiate service: This type of QoS is used to prioritize packets sent between the main controller and a robot regarding to different levels of importance in packets.
  

Hardware prototype:

Several mobile robots have been built for our testing and evaluation of the proposed control schemes. All robots are connected through a wireless network through a router, which can provide QoS to all end-to-end applications. The actual experiment is being set up using a CISCO 7000 router and several Linux-based PCs.