Contact Information Oak Ridge National Laboratory P.O. Box 2008 Building 7601, MS-6305 Oak Ridge, TN 37831-6305 Telephone: (865)574-9025 Fax: (865)574-4624 E-mail: dixonwe@ornl.gov

Dr. Warren Dixon received his B.S. and Ph.D. degrees in 1994 and 2000, respectively, from the Department of Electrical and Computer Engineering from Clemson University and his M.E. degree in 1997 from the Department of Electrical and Computer Engineering from the University of South Carolina.  After completing his doctoral studies he was selected as an ORNL Eugene P. Wigner Fellow where he currently works in the Robotics and Energetic Systems Group of the Engineering Science and Technology Division. Dr. Dixon’s main research interest has been the development and application of Lyapunov-based control techniques for mechatronic systems.  Recent publications have focused on Lyapunov-based control of nonlinear systems including: hydraulic systems, visual servoing systems, robotic systems, meso-scale mechanisms, underactuated systems, and nonholonomic systems.  Dr. Dixon was recently awarded the 2001 ORNL Early Career Award for Engineering Achievement for "sustained innovative advancements of nonlinear Lyapunov-based control of engineering systems."

Recent and Ongoing Research Projects

Visual Servo Control for Robotic Systems – This project is motivated by the desire to enable robotic systems with an improved sense of perception and intelligence to facilitate operation in unstructured and dynamically changing environments. The research efforts exploit nonlinear, Lyapunov-based design and analysis techniques to develop visual servo control algorithms that enable vision-based robotic motion despite the lack of depth information and/or knowledge of the camera calibration parameters. Current efforts have focused on the use of monocular approaches that reconstruct the Euclidean space through a projective homography. Other approaches include the use of a cooperative strategy that employs both a camera in-hand (providing a local, close-up view) and fixed camera (providing a global, wide range view). A high-speed (955 frames per second) vision system has been developed for experimental demonstrations using various robotic systems. For example projects, see the following links: Cooperative Visual Servoing (Camera-in-Hand and Fixed Camera) and Monocular Homography-Based Tracking of a Mobile Robot (Camera-in-Hand).

Wheeled Mobile Robot Control – This project is motivated by the desire to explore new control strategies for wheeled mobile robots that provide improved design flexibility and control performance. Recent efforts have focused on the development of nonlinear, Lyapunov-based design and analysis tools to construct an adaptive torque control input for mobile robots that can be utilized in a modular manner with parameter estimate update laws to enable unified tracking and regulation despite parametric uncertainty in the system. The impact of this research is that design/analysis techniques are developed that do not constrain the adaptive update law to a position/velocity based gradient update law. With the improved flexibility in the choice of the update law, improved tracking response is facilitated. For an overview of the experimental demonstration of this research see link to Modular Adaptive Project page.

Generalized Kinematics Formulation – This project is motivated by the desire to develop an automated mechanism to generate the Jacobian and forward kinematics of a generalized robotic system from a given D-H table. These efforts support the larger research efforts directed at simulating multi-optimization criteria-based robot behavioral adaptability and motion planning for highly redundant robots.

Meso-Scale Robotic Systems – This project is motivated by the desire to explore new locomotion concepts for robotic systems at the meso-scale. Recent efforts have been directed at the development of a novel piezoelectric-based locomotion design for a meso-scale mobile robot that exploits a compliant mechanical structure which enables piezoelectric forces to be amplified and transmitted to mechanisms that propel the robot through a lift and pull scheme. The lift and pull design contrasts with typical slip/stick approaches that assume the inertia effects of the robot will allow the robot to slip on a smooth surface.

Publications

Books

Dixon, W. E., A. Behal, D. M. Dawson, and S. Nagarkatti, Nonlinear Control of Engineering Systems: A Lyapunov-Based Approach, Birkhäuser Boston, 2003 (ISBN: 0-8176-4265-X).

Dixon, W. E., D. M. Dawson, E. Zergeroglu, and A. Behal, Nonlinear Control of Wheeled Mobile Robots, Vol. 262 Lecture Notes in Control and Information Sciences, Springer-Verlag London Ltd., 2000 (ISBN: 1-85233-414-2).


Journals

Dixon, W. E., M. S. de Queiroz, D. M. Dawson, and T. J. Flynn, “Adaptive Tracking and Regulation Control of a Wheeled Mobile Robot with Controller/Update Law Modularity,” IEEE Transactions on Control Systems Technology 12(1), 138–147 (2004).

Dixon, W. E., Y. Fang, D. M. Dawson, and T. J. Flynn, "Range Identification for Perspective Vision Systems," IEEE Transactions on Automatic Control 48(12), 2232–2238 (2003).

Dixon, W. E., E. Zergeroglu, and D. M. Dawson, "Global Robust Output Feedback Tracking Control of Robot Manipulators," Robotica, to appear.

Dixon, W. E. and J. Chen, "Comments on 'A Composite Energy Function-Based Learning Control Approach for Nonlinear Systems with Time-Varying Parametric Uncertainties'," IEEE Transactions on Automatic Control 48(9), 1671–1672 (2003).

Fang, Y., W. E. Dixon, D. M. Dawson, and E. Zergeroglu, "Nonlinear Coupling Control Laws for a 3-DOF Overhead Crane System," IEEE Transactions on Mechatronics 8(3), 418–423 (2003).

Dixon, W. E., E. Zergeroglu, D. M. Dawson, and B. T. Costic, "Repetitive Learning Control: A Lyapunov-Based Approach," IEEE Transactions on Systems, Man, and Cybernetics -Part B: Cybernetics 32(4), 538–545 (2002).

Dixon, W. E., D. M. Dawson, B. T. Costic, and M. S. de Queiroz, "A MATLAB-Based Control Systems Laboratory Experience for Undergraduate Students: Towards Standardization and Shared Resources," IEEE Transactions on Education 45(3), 218–226 (2002).

Behal, A., D. M. Dawson, W. E. Dixon, and Y. Fang, "Tracking and Regulation Control of an Underactuated Surface Vessel with Nonintegrable Dynamics," IEEE Transactions on Automatic Control 47(3), 495–500 (2002).

Dixon, W. E. and E. Zergeroglu, "Comments on ‘Adaptive Variable Structure Setpoint Control of Underactuated Robots," IEEE Transactions on Automatic Control 46(5), 812 (2001).

Dixon, W. E., D. M. Dawson, E. Zergeroglu, and A. Behal, "Adaptive Tracking Control of a Wheeled Mobile Robot via an Uncalibrated Camera System," IEEE Transactions on Systems, Man, and Cybernetics -Part B: Cybernetics 31(3), 341–352 (2001).

Dixon, W. E., I. D. Walker, D. M. Dawson, and J. P. Hartranft, "Fault Detection for Robot Manipulators with Parametric Uncertainty: A Prediction Error Based Approach," IEEE Transactions on Robotics and Automation 16(6), 689–699 (2000).

Dixon, W. E., D. M. Dawson, and E. Zergeroglu, "Tracking and Regulation Control of a Mobile Robot System with Kinematic Disturbances: A Variable Structure-Like Approach," Transactions of the ASME: Journal of Dynamic Systems, Measurement and Control: Special Issue on Variable Structure Systems 122, 616–623 (2000).

Dixon, W. E., Z. P. Jiang, and D. M. Dawson, "Global Exponential Setpoint Control of Wheeled Mobile Robots: A Lyapunov Approach," Automatica 36(11), 1741–1746 (2000).

de Queiroz, M. S., F. Zhang, and W. E. Dixon, "Comments on ‘Redesign of Hybrid Adaptive/Robust Motion Control of Rigid-Link Electrically-Driven Robot Manipulators,’" IEEE Transactions on Robotics and Automation 16(4), 448–449 (2000).

Dixon, W. E. and E. Zergeroglu, "Comments on Sliding-Mode Motion/Force Control of Constrained Robots," IEEE Transactions on Automatic Control 45(8), 1576–1577 (2000).

Zhang, F., D. M. Dawson, M. S. de Queiroz, and W. E. Dixon, "Global Adaptive Output Feedback Tracking Control of Robot Manipulators," IEEE Transactions on Automatic Control 45(6), 1203–1208 (2000).

Zergeroglu, E., W. E. Dixon, A. Behal, and D. M. Dawson, "Adaptive Set-Point Control of Robotic Manipulators with Amplitude-Limited Control Inputs," Robotica 18(2), 171–181 (2000).

Dixon, W. E., E. Zergeroglu, D. M. Dawson, and M. W. Hannan, "Global Adaptive Partial State Feedback Tracking Control of Rigid-Link Flexible-Joint Robots," Robotica 18(3), 325–336 (2000).

Dixon, W. E., D. M. Dawson, E. Zergeroglu, and F. Zhang, "Robust Tracking and Regulation Control for Mobile Robots," International Journal of Robust and Nonlinear Control: Special Issue on Control of Underactuated Nonlinear Systems 10, 199–216 (2000).

Dixon, W. E., D. M. Dawson, F. Zhang, and E. Zergeroglu, "Global Exponential Tracking Control of A Mobile Robot System via a PE Condition," IEEE Transactions on Systems, Man, and Cybernetics -Part B: Cybernetics 30(1), 129–142 (2000).

Zergeroglu, E., W. E. Dixon, D. M. Dawson, and A. Behal, "Lyapunov-Based Set-Point Control of the Acrobot," International Journal of Robotics and Automation 14(4), 161–170 (1999).

Feemster, M., D. M. Dawson, A. Behal, and W. E. Dixon, "Tracking Control in the Presence of Nonlinear Dynamic Frictional Effects: Robot Extension," Asian Journal of Control 1(3), 153–168 (1999).

Zergeroglu, E., W. E. Dixon, D. Haste, and D. M. Dawson, "Composite Adaptive Output Feedback Tracking Control of Robotic Manipulators," Robotica 17, 591–600 (1999).

Dixon, W. E., M. S. de Queiroz, D. M. Dawson, and F. Zhang, "Tracking Control of Robot Manipulators with Bounded Torque Inputs," Robotica 17, 121–129 (1999).

Conference

Pazderski, D., K. Kozlowshi, and W. E. Dixon, "Tracking and Regulation Control of a Skid-Steering Vehicle," Proceedings of the American Nuclear Society Tenth International Conference on Robotics and Remote Systems for Hazardous Environments, Gainesville, Florida, March 28–April 1, 2004, pp. 369–376.

Noakes, M. W. and W. E. Dixon, "Ergonomic Interface Concepts for Minimally Invasive, Remote, and Virtual Surgical Systems," 12th Annual Medicine Meets Virtual Reality Conference, Newport Beach, California, January 15–17, 2004, pp. 275–277.

Jung, D. L, W. E. Dixon, and F. G. Pin, "Automated Kinematic Generator for Surgical Robotic Systems, 12th Annual Medicine Meets Virtual Reality Conference, Newport Beach, California, January 15–17, 2004, pp. 144–146.

Chitrakaran, V., D. M. Dawson, W. E. Dixon, and J. Chen, "Identification of a Moving Object's Velocity with a Fixed Camera," Proceedings of the 2003 IEEE Conference on Decision and Control, Maui, Hawaii, December 2003, pp. 5402–5407.

Chen, J., A. Behal, D. M. Dawson, and W. E. Dixon, "Adaptive Visual Servoing in the Presence of Intrinsic Calibration Uncertainty," Proceedings of the 2003 IEEE Conference on Decision and Control, Maui, Hawaii, December 2003, pp. 5396–5401.

Fang, Y., W. E. Dixon, D. M. Dawson, and J. Chen, "An Exponential Class of Model-Free Visual Servoing Controllers in the Presence of Uncertain Camera Calibration," Proceedings of the 2003 IEEE Conference on Decision and Control, Maui, Hawaii, December 2003, pp. 5390–5395.

Dixon, W. E., "Teach by Zooming: A Camera Independent Alternative to Teach by Showing Visual Servo Control," Proceedings of the 2003 IEEE International Conference on Intelligent Robots and Systems, Las Vegas, Nev., October 2003, pp. 749–754.

Chen, J., D. M. Dawson, W. E. Dixon, and A. Behal, "Adaptive Homography-Based Visual Servo Tracking," Proceedings of the IEEE International Conference on Intelligent Robots and Systems, Las Vegas, Nev., October 2003, pp. 230–235.

Chen, J., W. E. Dixon, D. M. Dawson, and M. McIntire, "Homography-Based Visual Servo Tracking Control of a Wheeled Mobile Robot," Proceedings of the 2003 IEEE International Conference on Intelligent Robots and Systems, Las Vegas, Nev., October 2003, pp. 1814–1819.

Dixon, W. E, Y. Fang, D. M. Dawson, and J. Chen, "Adaptive Range Identification for Exponential Visual Servo Control," Proceedings of the 2003 IEEE International Symposium on Intelligent Control, Houston, Tex., October 2003, pp. 46–51.

Dixon, W. E., Y. Fang, D. M. Dawson, and T. J. Flynn, "Range Identification for Perspective Vision Systems," Proceedings of the 2003 IEEE American Control Conference, Denver, Colo., June 2003, pp. 3448–3453.

Fang, Y., W. E. Dixon, D. M. Dawson, and J. Chen, "Robust 2.5D Visual Servoing for Robot Manipulators," Proceedings of the 2003 IEEE American Control Conference, Denver, Colo., June 2003, pp. 3311–3316.

Fang, Y., A. Behal, W. E. Dixon, and D. M. Dawson, "Adaptive 2.5D Visual Servoing of Kinematically Redundant Robot Manipulators," Proceedings of the 2002 IEEE Conference on Decision and Control, Las Vegas, Nev., December 10–13, 2002, pp. 2860–2865.

Fang. Y., D. M. Dawson, W. E. Dixon, and M. S. de Queiroz, "Homography-Based Visual Servoing of Wheeled Mobile Robots," Proceedings of the 2002 IEEE Conference on Decision and Control, Las Vegas, Nev., December 10–13, 2002, pp. 2866–2871.

Chen, J., W. E. Dixon, J. R. Wagner, and D. M. Dawson, "Exponential Tracking Control of a Hydraulic Proportional Directional Valve and Cylinder via Integrator Backstepping," Proceedings of the 2002 ASME International Mechanical Engineering Congress and Exposition, New Orleans, La., November 17–22, 2002.

Dixon, W. E. and L. J. Love, "Lyapunov-based Visual Servo Control for Robotic Deactivation and Decommissioning," Proceedings of the ANS Spectrum 2002: International Conference on Nuclear and Hazardous Waste Management, Reno, Nev., August 4–8, 2002.

Dixon, W. E., M. S. de Queiroz, and D. M. Dawson, "Adaptive Tracking and Regulation Control of a Wheeled Mobile Robot with Controller/Update Law Modularity," Proceedings of the 2002 IEEE International Conference on Robotics and Automation, Wasington, D.C., May 11–15, 2002, pp. 2620–2625.

Varma, V. K. and W. E. Dixon, "Design of a Piezoelectric Meso-Scale Mobile Robot: A Compliant Amplification Approach," Proceedings of the 2002 IEEE International Conference on Robotics and Automation, Washington, D.C., May 11–15, 2002, pp. 1137–1142 .

Dixon, W. E., E. Zergeroglu, Y. Fang, and D. M. Dawson, "Object Tracking by a Robot Manipulator: A Robust Cooperative Visual Servoing Approach," Proceedings of the 2002 IEEE International Conference on Robotics and Automation, Washington, D.C., May 11–15, 2002, pp. 211–216.

Fang, Y., W. E. Dixon, D. M. Dawson, and E. Zergeroglu, "Nonlinear Coupling Control Laws for a 3-DOF Overhead Crane System," Proceedings of the 2001 IEEE Conference on Decision and Control, Orlando, Fla., December 4–7, 2001, pp. 3766–3771.

Dixon, W. E., D. Moses, I. D. Walker, and D. M. Dawson, "A Simulink-Based Robotic Toolkit for Simulation and Control of the PUMA 560 Robot Manipulator," Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Maui, Hawaii, November 2001, pp. 2202-2207.

Fang, Y., E. Zergeroglu, W. E. Dixon, and D. M. Dawson, "Nonlinear Coupling Control Laws for an Overhead Crane System," Proceedings of the 2001 IEEE Conference on Control Applications, Mexico City, Mexico, September 5–7, 2001, pp. 639–644.

Dixon, W. E., E. Zergeroglu, D. Dawson, and B. T. Costic, "Repetitive Learning Control: A Lyapunov-Based Approach," Proceedings of the 2001 IEEE Conference on Control Applications, Mexico City, Mexico, September 5–7, 2001, pp. 530–535.

Dixon, W. E., I. D. Walker, and D. M. Dawson, "Fault Detection for Wheeled Mobile Robots with Parametric Uncertainty," Proceedings of the 2001 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Como, Italy, July 2001, pp. 1245–1250.

Dixon, W. E., D. M. Dawson, B. T. Costic, and M. S. de Queiroz, "Towards the Standardization of a MATLAB-Based Control Systems Laboratory Experience for Undergraduate Students," Proceedings of the American Control Conference, Arlington, Va., June 2001, pp. 1161–1166.

Setlur, P., A. Behal, W. E. Dixon, and D. M. Dawson, "Adaptive Position and Orientation Regulation for the Camera-in-Hand Problem," Proceedings of the 2001 International Symposium on Adaptive and Intelligent Systems and Control, Charlottesville, Va., June 2001.

Behal, A., W.E. Dixon, D. M. Dawson, and Y. Fang, "Tracking and Regulation Control of an Underactuated Surface Vessel with Nonintegrable Dynamics," Proceedings of the 39th IEEE Conference on Decision and Control, Sydney, Australia, December 2000, pp. 2150–2155.

Dixon, W. E., D. M. Dawson, and E. Zergeroglu, "Robust Control of a Mobile Robot System with Kinematic Disturbances," Proceedings of the IEEE International Conference on Control Applications, Anchorage, Alaska, September 2000, pp. 437–442.

Dixon, W. E., D. M. Dawson, E. Zergeroglu, and A. Behal, "Adaptive Tracking Control of a Wheeled Mobile Robot via an Uncalibrated Camera System," Proceedings of the 2000 American Control Conference, Chicago, Ill., June 2000, pp. 1493–1497.

Dixon, W. E., I. D. Walker, D. M. Dawson, and J. P. Hartranft, "Fault Detection for Robotic Manipulators with Parametric Uncertainty: A Prediction Error Based Approach," Proceedings of the IEEE International Conference on Robotics and Automation, San Francisco, Calif., April 2000, pp. 3628–3634.

Dixon, W. E., D. M. Dawson, F. Zhang, and E. Zergeroglu, "Global Exponential Tracking Control of A Mobile Robot System via a PE Condition," Proceedings of the 38th IEEE Conference on Decision and Control, Phoenix, Ariz., December 1999, pp. 4822–4827.

Dixon, W. E., E. Zergeroglu, D. M. Dawson, and M. W. Hannan, "Global Adaptive Partial State Feedback Tracking Control of Rigid-Link Flexible-Joint Robots," Proceedings of the 1999 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Atlanta, Ga., September 1999, pp. 281–286.

Dixon, W. E., D. M. Dawson, F. Zhang, and E. Zergeroglu, "Global Exponential Setpoint Control of Mobile Robots," Proceedings of the 1999 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Atlanta, Ga., September 1999, pp. 683–688.

Dixon, W. E., D. M. Dawson, E. Zergeroglu, and F. Zhang, "Robust Tracking Control of a Mobile Robot System," Proceedings of the 1999 IEEE International Conference on Control Applications, Kohala Coast, Hawaii, August 1999, pp. 1015–1020.

Feemster, M., D. M. Dawson, A. Behal, and W. E. Dixon, "Tracking Control in the Presence of Nonlinear Dynamic Frictional Effects: Robot Extension," Proceedings of the Conference on Control Applications, Kohala Coast, Hawai, August 1999, pp. 1169–1174.

Zergeroglu, E., W. E. Dixon, A. Behal, and D. M. Dawson, "Composite Adaptive Output Feedback Tracking Control of Robotic Manipulators," Proceedings of the 1999 American Control Conference, San Diego, Calif., June 1999, pp. 3013–3017.

Dixon, W. E., F. Zhang, D. M. Dawson, and A. Behal, "Global Robust Output Feedback Tracking Control of Robot Manipulators," Proceedings of the 1998 IEEE International Conference on Control Applications, Trieste, Italy, September 1998, pp. 897–901.

Zergeroglu, E., W. E. Dixon, D. M. Dawson, and M. W. Hannan, "Lyapunov-Based Set-Point Control of the Acrobot," Proceedings of the 1998 IEEE International Conference on Control Applications, Trieste, Italy, September 1998, pp. 887–891.

Dixon, W. E., M. S. de Queiroz, D. M. Dawson, and F. Zhang, "Tracking Control of Robot Manipulators with Bounded Torque Inputs," Proceedings of the 6th IASTED International Conference on Robotics and Manufacturing, Banff, Canada, July 1998, pp.112–115.

Dixon, W. E., E. Zergeroglu, D. M. Dawson, and M. S. de Queiroz, "Global Output Feedback Tracking Control for Rigid-Link Flexible-Joint Robots," Proceedings of the 1998 IEEE International Conference on Robotics and Automation, Leuven, Belgium, May 1998, pp. 498–504.

Zhang, F., D. M. Dawson, M. S. de Queiroz, and W. E. Dixon, "Global Adaptive Output Feedback Tracking Control of Robot Manipulators," Proceedings of the 36th IEEE Conference on Decision and Control, San Diego, Calif., December 1997, pp. 3634–3639.


Videos

Dixon, W. E., E. Zergeroglu, D. M. Dawson, and M. W. Hannan, "Experimental Video of a Controller for Flexible Joint Robots," Video Proceedings of the 1999 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Atlanta, Ga., September 1999.

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Last updated: April 16, 2004