Recent Research Projects

Recent Research Projects - 2007

Michael Lemmon, University of Notre Dame

Self-Triggered Feedback over Networked Control Systems - National Science Foundation (2007-2010)
Personnel: Dr. Michael Lemmon, Dr Xiaobo Hu

Description: This fundamental research project examines the minimum amount of feedback information required to achieve a specified level of performance in a networked control system. The project examines the use of event-triggered and self-triggered feedback as a means of tailoring the amount of feedback information to what's actually going on in the system. We're particularly interested in how such event triggering would work over wireless networks.
Publications:

X. Wang and M. Lemmon (2008), Decentralized Event-triggering Broadcast over Networked Systems, , to appear in Hybrid Systems: computation and control, 2008.
X. Wang and M. Lemmon (2008), State based Self-triggered feedback control systems with L2 stability, to appear in 17th IFAC world congress, 2008.
X. Wang and M. Lemmon (2007), Self-triggered Feedback Control Systems with Finite-Gain L2 Stability,accepted (subject to revision) to IEEE Transactions on Automatic Control, June, 2007.
X. Wang and M. Lemmon (2008), Event-triggered Broadcasting across Distributed Networked Control Systems, , submitted to American Control Conference, , 2008.
M. Lemmon, T. Chantem, X. Hu, and M. Zyskowski (2007), On Self-Triggered Full Information H-infinity Controllers, Hybrid Systems: Computation and Control, April 2007.

Metropolitan Scale Sensor-Actuator Networks for Combined Sewer Overflows- Indiana 21st CTF and EmNet LLC (2007-2009)
Personnel: Dr. Michael Lemmon, Mr. Pu Wan, Dr. Luis Montestruque

Description: A large-scale distributed system is a dynamical system consisting of several interconnected subsystems. A "centralized" approach for controlling such systems has a single controller regulating the behavior of all subsystems. This approach does not scale well since the complexity of the communication network supporting centralized feedback control becomes unwieldy as the number of subsystems increases. We therefore consider the possibility of using a group of "decentralized" controllers to regulate the overall system's behavior. In decentralized controllers, an individual subsystem's controller makes its decisions only based on information from a select set of neighbors. The communication required to support such a decentralized controller is usually a multi-hop communication network which can have inherent limits on the rate at which feedback data can be shared between subsystems. This research project is designing the control system to be used in a metropolitan-scale deployment of a sensor-actuator network being used to reduce the frequency of combined sewer overflow events in city sewer systems.
Publications:

L. Montestruque and M.D. Lemmon (2008), CSOnet: a metropolitan scale wireless sensor-actuator network, submitted to International Workshop on Mobile Device and Urban Sensing (MODUS), 2008
P. Wan and M. Lemmon (2007), Distributed Flow Control using Embedded Sensor-Actuator Networks for the Reduction of Combined Sewer Overflow (CSO) Events, IEEE Conference on Decision and Control, 2007.

Distributed Estimation and Control of Flow Fields - Crane Naval Base and DTRA (2007-2011)
Personnel: Dr. Michael Lemmon

Description: This is a new project examining the use of distributed processes to monitor and control dynamical systems characterized by field flows such as Maxwell's equations and the Navier-Stokes equations. We're particularly interested in using these techniques to develop novel methods for tracking airborne plumes of contaminants. Joint work with the dept. of environmental engineering is interested in using this work to image subsurface groundwater contaminants. Most of our initial work in this area has focused on consensus estimation.
Publications:

Y. Sun and M. Lemmon (2007), Convergence of Consensus Filtering under Network Throughput Limitations , IEEE Conference on Decision and Control, 2007.
Y. Sun and M. Lemmon (2007), Swarming under Perfect Consensus using Integral Action American Control Conference , 2007.
M.D. Lemmon and Y. Sun (2006), Cohesive Swarming under Consensus, IEEE Conference on Decision and Control, 2006.
A. Nightingale, D.A. Duffin, M. Lemmon, B. Goodwine, and E. Jumper (2006), Adaptive-Optic Correction of a Regularized Compressible Shear Layer, 37th AIAA Plasmadynamics and Lasers Conference, June 5-8, 2006, San Francicso, CA.

Real-Time Control Systems - National Science Foundation (2004-2008)
Personnel: Dr. Michael Lemmon, Dr. Xiaobo Sharon Hu, Ms. Thidapat Chantem, Mr. Xiaofeng Wang

Description: Hard periodic real-time systems are computer systems running periodic task sets whose jobs must be completed before a specified deadline. Hard periodic real-time has dominated the development of most computer control systems since this allows us to use discrete-time system models to predict the closed loop system's performance. This approach, however, can also result in significant over-provisioning of the computer system implementing the controller. The objective of this research work is to develop soft or firm real-time systems for computer control that are still able to provide guarantees on feedback control system performance.
Publications:

T. Chantem, X.S. Hu, and M.D. Lemmon (2007), Period and Deadline Selection Problem for Real-Time Systems, Real Time Systems Symposium: work-in-progress track(RTSS07), 2007.
T. Chantem, X. Hu, and M.D. Lemmon (2006), Generalized Elastic Scheduling, IEEE Real Time Systems Symposium, 2006,
X. Hu, T. Chantem, and M.D. Lemmon (2006), Optimal Elastic Scheduling, IEEE Real-Time and Embedded Technology and Applications Symposium (works in progress track), 2006.
D. Liu, X. Hu, M.D. Lemmon, and Q. Ling (2006), Firm Real-Time System Scheduling Based on a Novel QoS Constraint, IEEE Transactions on Computers, March 2006.
D. Liu, X. Hu, M.D. Lemmon, and Q. Ling (2005), Scheduling Tasks with Markov-Chain Constraints, 17th Euromicro Conference on Real-time Systems, July 2005.
X. Sharon Hu, Donglin Liu, Michael D. Lemmon, and Qiang Ling (2003), Firm Real-Time System Scheduling Based on a Novel QoS Constraint, Real Time Systems Symposium (RTSS03), Cancun Mexico, November 2003.

OLD PROJECTS (2006)