Tim Bretl

• Assistant Professor of Aerospace Engineering
• University of Illinois at Urbana-Champaign


• Curriculum Vitae

Contact

• Office: 148 Coordinated Science Laboratory
• Phone: (217) 244-3126
• Email: tbretl@illinois.edu
• Research Group: RMS Lab

Affiliations

• Coordinated Science Laboratory
• Beckman Institute for Advanced Science and Technology
• Department of Computer Science
• Department of Electrical and Computer Engineering
• Neuroscience Program

Education

• Postdoc, Computer Science, Stanford University (2005-2006)
• PhD, Aeronautics and Astronautics, Stanford University (2005)
• MS, Aeronautics and Astronautics, Stanford University (2000)
• BA, Mathematics, Swarthmore College (1999)
• BS, Engineering, Swarthmore College (1999)

Teaching

• AE 583/ECE550: Advanced Robotic Planning (2009), (2011)
• AE 483: Aerospace Decision Algorithms (Spring 2011), (Fall 2011), (2012)
• AE 482/ECE470: Introduction to Robotics (2009), (2012)
• AE 403: Spacecraft Attitude Control (2008), (2010), (2012)
• AE 252: Introduction to Aerospace Dynamics (2007), (2009)
• AE 100SD: Introduction to Aerospace Engineering - Spacecraft Design (2010)
• AE 498 MPA (2006), (2007), (2008)

Book Chapters and Journal Publications

• [19] T. Bretl and Z. McCarthy, "Quasi-Static Manipulation of a Kirchhoff Elastic Rod based on a Geometric Analysis of Equilibrium Configurations," conditionally accepted for publication in the International Journal of Robotics Research, 2012. [by request]
• [18] T. Bretl and Z. McCarthy, "Mechanics and Quasi-Static Manipulation of Planar Elastic Kinematic Chains," accepted for publication in IEEE Transactions on Robotics, 2012. [by request]
• [17] K. A. Shorter, Y. Li, T. Bretl, and E. T. Hsiao-Wecksler, "Modeling, control, and analysis of a robotic assist device," Mechatronics, 22(8):1067-1077, 2012. [pdf]
• [16] R. D. Gregg, A. Tilton, S. Candido, T. Bretl, and M. Spong, "Control and Planning of 3D Dynamic Walking with Asymptotically Stable Gait Primitives," IEEE Transactions on Robotics, 28(6):1415-1423, 2012. [pdf]
• [15] A. Becker and T. Bretl, "Approximate Steering of a Unicycle Under Bounded Model Perturbation Using Ensemble Control," IEEE Transactions on Robotics, 28(3):580-591, 2012. [pdf]
• [14] T. Bretl, "Minimum-Time Optimal Control of Many Robots that Move in the Same Direction at Different Speeds," IEEE Transactions on Robotics, 28(2):351-363, 2012. [pdf] [mp4]
• [13] R. Ma, N. Aghasadeghi, J. A. Jarzebowski, T. Bretl, and T. P. Coleman, "A Stochastic Control Approach to Optimally Designing Variable-Sized Menus in P300 Communication Prostheses," IEEE Transactions on Neural Systems and Rehabilitation Engineering, 20(1):102-112, 2012. [pdf]
• [12] Y. Li, A. Becker, K. A. Shorter, T. Bretl, and E. T. Hsiao-Wecksler, "Estimating System State During Human Walking with a Powered Ankle-Foot Orthosis," IEEE/ASME Transactions on Mechatronics, vol. 16, no. 5, October 2011 [pdf]
• [11] C. Omar, A. Akce, M. Johnson, T. Bretl, R. Ma, E. Maclin, M. McCormick, and T. P. Coleman, "A Feedback Information-Theoretic Approach to the Design of Brain-Computer Interfaces," International Journal of Human-Computer Interaction, vol. 27, iss. 1, pp. 5-23, 2011. [pdf]
• [10] T. Bretl, G. Arechavaleta, A. Akce, and J. P. Laumond, "Comments on 'An Optimality Principle Governing Human Walking'," IEEE Transactions on Robotics, vol. 26, iss. 6, pp. 1105-1106, 2010. [pdf]
• [9] T. Bretl. "Control of Many Agents by Moving Their Targets: Maintaining Separation," Recent Progress in Robotics: Viable Robotic Service to Human, Lecture Notes in Control and Information Sciences (LNCIS), vol 370, pp. 145-156, 2008. [pdf]
• [8] K. Hauser, T. Bretl, J. Latombe, K. Harada, and B. Wilcox, "Motion Planning for Legged Robots on Varied Terrain," The International Journal of Robotics Research, vol. 27, iss. 11-12, pp. 1325-1349, 2008. [pdf]
• [7] T. Bretl and S. Lall, "Testing Static Equilibrium for Legged Robots," IEEE Transactions on Robotics, vol. 24, iss. 4, pp. 794-807, 2008. [pdf]
• [6] K. Hauser, T. Bretl, K. Harada, and J. Latombe, "Using motion primitives in probabilistic sample-based planning for humanoid robots," Algorithmic Foundations of Robotics VII, Springer Tracts in Advanced Robotics (STAR), Springer Berlin / Heidelberg, vol 47, p507-522, 2008. [pdf]
• [5] K. Hauser, T. Bretl, J. Latombe, and B. Wilcox, "Motion planning for a six-legged lunar robot," Algorithmic Foundations of Robotics VII, Springer Tracts in Advanced Robotics (STAR), Springer Berlin / Heidelberg, vol 47, p301-316, 2008. [pdf]
• [4] T. Bretl, "Motion Planning of Multi-Limbed Robots Subject to Equilibrium Constraints: The Free-Climbing Robot Problem," International Journal of Robotics Research, vol. 25, iss. 4, pp. 317-342, 2006. [pdf]
• [3] T. Bretl, S. Rock, J.C. Latombe, B. Kennedy, and H. Aghazarian. "Free-Climbing with a Multi-Use Robot," Experimental Robotics IX, Springer Tracts in Advanced Robotics (STAR), Springer Berlin / Heidelberg, vol. 21, p449-458, 2008. [pdf]
• [2] T. Bretl, S. Lall, J.C. Latombe, and S. Rock. "Multi-Step Motion Planning for Free-Climbing Robots," Algorithmic Foundations of Robotics VI, Springer Tracts in Advanced Robotics (STAR), Springer Berlin / Heidelberg, vol 17, p59-74, 2008. [pdf]
• [1] T. Bretl, J.C. Latombe, and S. Rock. "Toward Autonomous Free-Climbing Robots," Robotics Research, Springer Tracts in Advanced Robotics (STAR), Springer Berlin / Heidelberg, vol 15, p6-15, 2005. [pdf]

Peer-Reviewed Conference Publications

• [48] D. Matthews and T. Bretl, "Experiments in Quasi-Static Manipulation of a Planar Elastic Rod," to appear in IEEE/RSJ International Conference on Intelligent Robotics and Systems (IROS), 2012.
• [47] C. Orduno, A. Becker, and T. Bretl, "Motion Primitives for Path Following with a Self-Assembled Robotic Swimmer," to appear in IEEE/RSJ International Conference on Intelligent Robotics and Systems (IROS), 2012.
• [46] A. Akce, J. Norton, and T. Bretl, "A Brain-Machine Interface to Navigate Mobile Robots Along Human-Like Paths Amidst Obstacles," to appear in IEEE/RSJ International Conference on Intelligent Robotics and Systems (IROS), 2012.
• [45] A. Becker, C. Onyuksel, and T. Bretl, "Feedback Control of Many Differential-Drive Robots with Uniform Control Inputs," to appear in IEEE/RSJ International Conference on Intelligent Robotics and Systems (IROS), 2012.
• [44] A. Becker and T. Bretl, "Approximate Steering of a Plate-Ball System Under Bounded Model Perturbation Using Ensemble Control," to appear in IEEE/RSJ International Conference on Intelligent Robotics and Systems (IROS), 2012.
• [43] A. Akhtar, L. J. Hargrove, and T. Bretl, "Prediction of Distal Arm Joint Angles from EMG and Shoulder Orientation for Prosthesis Control," in the International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), August 2012.
• [42] T. Bretl and Z. McCarthy, "Equilibrium Configurations of a Kirchhoff Elastic Rod Under Quasi-Static Manipulation," in Workshop on Algorithmic Foundations of Robotics (WAFR), June 2012. [pdf]
• [41] A.-S. Puydupin-Jamin, M. Johnson, and T. Bretl, "A convex approach to inverse optimal control and its application to modeling human locomotion," in IEEE International Conference on Robotics and Automation (ICRA), May 2012. [pdf]
• [40] Z. McCarthy, T. Bretl, and S. Hutchinson, "Proving path non-existence using sampling and alpha shapes," in IEEE International Conference on Robotics and Automation (ICRA), May 2012. [pdf]
• [39] N. Aghasadeghi, A. Long, and T. Bretl, "Inverse optimal control for a hybrid dynamical system with impacts," in IEEE International Conference on Robotics and Automation (ICRA), May 2012. [pdf]
• [38] S. Hutchinson and T. Bretl, "Robust optimal deployment of mobile sensor networks," in IEEE International Conference on Robotics and Automation (ICRA), May 2012. [pdf]
• [37] Z. McCarthy and T. Bretl, "Mechanics and manipulation of planar elastic kinematic chains," in IEEE International Conference on Robotics and Automation (ICRA), May 2012. Winner of Best Manipulation Paper Award. [pdf] [mp4]
• [36] D. Bonnie, S. Candido, T. Bretl, and S. Hutchinson, "Modelling search with a binary sensor utilizing self-conjugacy of the exponential family," in IEEE International Conference on Robotics and Automation (ICRA), May 2012. [pdf]
• [35] Y. Li, K. A. Shorter, E. T. Hsiao-Wecksler, and T. Bretl, "Simulation and Experimental Analysis of a Portable Powered Ankle-Foot Orthosis Control," in ASME Dynamic Systems and Control Conference, Arlington, VA, 2011.
• [34] E. A. Morris, K. A. Shorter, Y. Li, E. T. Hsiao-Wecksler, T. Bretl, G. F. Kogler, and W. K. Durfee, "Actuation Timing Strategies for a Portable Powered Ankle Foot Orthosis," in ASME Dynamic Systems and Control Conference, Arlington, VA, 2011.
• [33] C. Das, A. Becker, and T. Bretl, "Probably Approximately Correct Coverage for Robots With Uncertainty," in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2011. [pdf]
• [32] N. Aghasadeghi and T. Bretl, "Maximum Entropy Inverse Reinforcement Learning in Continuous State Spaces with Path Integrals," in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2011. [pdf]
• [31] A. Akce and T. Bretl, "A Compact Representation of Locally-Shortest Paths and its Application to a Human-Robot Interface," in IEEE International Conference on Robotics and Automation (ICRA), 2011. [pdf]
• [30] D. Steines, T. Bretl, E. Maclin, and T. Coleman, "Application of Feedback-Related Negativity to Brain-Computer Interface," Society for Neuroscience, San Diego, CA, 2010.
• [29] A. Akce and T. Bretl, "A Probabilistic Language Model for Hand Drawings," in Pattern Recognition (ICPR), 2010 20th International Conference on, 2010, pp. 109-112. [pdf]
• [28] R. Gregg, T. Bretl, and M. Spong, "A Control Theoretic Approach to Robot-Assisted Locomotor Therapy," IEEE Conference on Decision and Control (CDC), Atlanta, GA, 2010. [pdf]
• [27] A. Becker and T. Bretl, "Motion planning under bounded uncertainty using ensemble control," in Robotics: Science and Systems (RSS), 2010. [pdf]
• [26] R. D. Gregg, T. Bretl, and M. W. Spong, "Asymptotically stable gait primitives for planning dynamic bipedal locomotion in three dimensions," in IEEE International Conference on Robotics and Automation (ICRA), 2010, pp. 1695-1702. [pdf]
• [25] A. Akce, M. Johnson, and T. Bretl, "Remote teleoperation of an unmanned aircraft with a brain-machine interface: Theory and preliminary results," in IEEE International Conference on Robotics and Automation (ICRA), 2010, pp. 5322-5327.[pdf]
• [24] I. R. De Pablo, A. Becker, and T. Bretl, "An optimal solution to the linear search problem for a robot with dynamics," in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2010, pp. 652-657. [pdf]
• [23] A. Becker, R. Sandheinrich, and T. Bretl, "Automated manipulation of spherical objects in three dimensions using a gimbaled air jet," in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2009, pp. 781-786. [pdf]
• [22] D. DeVon and T. Bretl, "Control of many agents moving in the same direction with different speeds: a decoupling approach," in American Control Conference (ACC), 2009. [pdf]
• [21] C. Omar, M. Johnson, T. Bretl, and T. P. Coleman, "Policies for neural prosthetic control: initial experiments with a text interface," in American Control Conference (ACC), Seattle, WA, 2008. [pdf]
• [20] C. Omar, M. Johnson, T. Bretl, and T. Coleman, "Querying the user properly for high-performance brain-machine interfaces: recursive estimation, control, and feedback information-theoretic perspectives," in IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), Las Vegas, NV, 2008. [pdf]
• [19] T. Bretl, "Control of Many Agents by Moving their Targets: Maintaining Separation," in International Conference on Advanced Robotics (ICAR), Jeju, Korea, 2007. [pdf]
• [18] T. Bretl, "Control of many agents using few instructions," in Robotics: Science and Systems (RSS), Atlanta, GA, 2007. [pdf]
• [17] D. DeVon and T. Bretl, "Kinematic and Dynamic Control of a Wheeled Mobile Robot," in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2007. [pdf]
• [16] T. Bretl and S. Lall, "A Fast and Adaptive Test of Static Equilibrium for Legged Robots," in IEEE International Conference on Robotics and Automation (ICRA), 2006. [pdf]
• [15] K. Harada, K. Hauser, T. Bretl, and J. Latombe, "Natural motion generation for humanoid robots," in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Beijing, China, 2006. [pdf]
• [14] T. Miller, T. Bretl, and S. Rock, "Control of a climbing robot using real-time convex optimization," in IFAC Symposium on Mechatronic Systems, Heidelberg, Germany, 2006. [pdf]
• [13] K. Hauser, T. Bretl, K. Harada, and J. Latombe, "Using motion primitives in probabilistic sample-based planning for humanoid robots," in Workshop on the Algorithmic Foundations of Robotics (WAFR), New York, NY, 2006. [pdf]
• [12] K. Hauser, T. Bretl, J. Latombe, and B. Wilcox, "Motion planning for a six-legged lunar robot," in Workshop on the Algorithmic Foundations of Robotics (WAFR), New York, NY, 2006. [pdf]
• [11] K. Hauser, T. Bretl, and J. Latombe, "Learning-Assisted Multi-Step Planning," in IEEE International Conference on Robotics and Automation (ICRA), Barcelona, Spain, 2005. [pdf]
• [10] K. Hauser, T. Bretl, and J. Latombe, "Non-Gaited Humanoid Locomotion Planning," in Humanoids, Tsukuba, Japan, 2005. [pdf]
• [9] T. Bretl, S. Rock, J. Latombe, B. Kennedy, and H. Aghazarian, "Free-Climbing with a Multi-Use Robot," in International Symposium on Experimental Robotics (ISER), Singapore, 2004. [pdf]
• [8] T. Bretl, S. Lall, J. Latombe, and S. Rock, "Multi-Step Motion Planning for Free-Climbing Robots," in Workshop on the Algorithmic Foundations of Robotics (WAFR), Zeist, Netherlands, 2004. [pdf]
• [7] T. Bretl, S. Rock, and J. Latombe, "Motion Planning for a Three-Limbed Climbing Robot in Vertical Natural Terrain," in IEEE International Conference on Robotics and Automation (ICRA), Taipei, Taiwan, 2003. [pdf]
• [6] T. Bretl, T. Miller, S. Rock, and J. Latombe, "Climbing Robots in Natural Terrain," in i-SAIRAS, Nara, Japan, 2003.[pdf]
• [5] T. Bretl, J. Latombe, and S. Rock, "Toward Autonomous Free-Climbing Robots," in International Symposium on Robotics Research (ISRR), Siena, Italy, 2003. [pdf]
• [4] T. Bretl and S. Rock, "Planning Robust Dynamic Transitions for Enhanced Mobility of Planetary Rovers," in IFAC Conference on Mechatronic Systems, Berkeley, CA, 2002, pp. 109-114. [pdf]
• [3] T. Bretl and S. Rock, "Robust Execution of Aggressive Maneuvers for Planetary Robotics," in AIAA Guidance, Navigation, and Control Conference and Exhibit (AIAA-GNC), Monterey, CA, 2002. [pdf]
• [2] C. M. Clark, T. Bretl, and S. Rock, "Applying kinodynamic randomized motion planning with a dynamic priority system to multi-robot space systems." 2002, pp. 7-3621. [pdf]
• [1] K. Stein, R. Benney, T. Tezduyar, V. Kalro, J. Potvin, and T. Bretl, "Fluid-Structure Interaction Simulation of a Cross Parachute: Comparison of Numerical Predictions with Wind Tunnel Data," in CEAS/AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar, Toulouse, France, 1999. [pdf]

Thesis

• T. Bretl, "Multi-Step Motion Planning: Application to Free-Climbing Robots," PhD Thesis , 2005. [pdf]

Links

• Robotics and neuro-Mechanical Systems Lab (RMS Lab)
• Brain-Machine Interface Group at Illinois
• Old Version of This Website