Kaveh Akbari Hamed

Curriculum Vitae (Updated December 2013)


I am currently a postdoctoral research fellow working with Prof. Jessy W. Grizzle at the Electrical Engineering and Computer Science Department of the University of Michigan. My research interests span control theory, nonlinear and robust control, robotics, hybrid systems, dynamical systems, optimization, and power systems. I develop nonlinear feedback control solutions for dynamical models ranging from robotic systems to power systems. The models of these systems are typically characterized by high dimensional state spaces, with nonlinear and hybrid dynamics. My research has a clear path from theory to practice. While the bulk of my experience has been on the theoretical side of these subjects, recently, in my postdoctoral studies, I have been pursuing experimental implementation of my work on a challenging 3D bipedal robot, ATRIAS.

We are on the verge of a new revolution in robotic legged locomotion. During the past three decades enormous advances have occurred in control and motion planning of dynamic locomotion of legged robots. In particular, hundreds of walking mechanisms have been built in research laboratories and companies throughout the world. The study of legged locomotion has been motivated by the desire to allow people with disabilities to walk and to replace humans in hazardous environments with capable machines. Over the coming years and decades, the development of an agile and stable bipedal robot with a desired level of control will impact the developing world in even greater ways than may now be imaginable. Walking or bipedal robots will help people with physical disabilities or aid in disaster response. However, there is still a long way to go to make this a reality. In particular, while the technology involved in robot construction is advancing rapidly, the science of stabilization of trajectories for these robots based on feedback control algorithms to achieve standing, walking, stepping over obstacles, etc. is lagging.

Robotic legged locomotion can be modeled as hybrid systems. Steady-state locomotion corresponds to a periodic orbit in the model. For researchers within the control systems community, underlying the study of energy-efficient, dynamic, robust and asymptotically stable legged locomotion, is the challenging mathematical problem of determining the existence and robust stability of periodic solutions (e.g., walking and running locomotion) to hybrid systems describing locomotion by robots. The feedback controllers for these systems can be hybrid as well, including both continuous and discrete (event-based) actions. Furthermore, modern complex engineering systems necessitate the application of multiple modes of operation which places stringent demands on controller design. Such systems typically possess a multi-echelon hierarchical hybrid control architecture.

My research is interdisciplinary and well positioned to develop systematic methods, based on robust nonlinear control, hybrid control theory and optimization, for controlling a class of dynamical systems arising from mechanical systems and power electronics. The results of this research can be used for achieving stable, agile, efficient and robust locomotion in legged robots, especially bipedal robots. They can also be used to improve the control of existing robots, machines, mechanical systems interrupted by collision, electronic power systems interrupted by switches, and also to provide guidelines for improving the mechanical design of future robots, controlled prosthetic legs and wearable robots (biomedical applications) and power electronics devices.

Research Interests:

Feedback Control Theory, Nonlinear and Robust Control, Robotics, Hybrid Systems, Dynamical Systems, Optimization, Control of Legged Locomotion, and Power Electronics Systems.

Research Group: Prof. Jessy W. Grizzle (Dynamic Leg Locomotion Lab)

Selected Recent Publications:
  • K. Akbari Hamed and J. W. Grizzle, Event-based stabilization of periodic orbits for underactuated 3D bipedal robots with left-right symmetry,” IEEE Transactions on Robotics, vol. 30, issue 2, pp. 365-381, April 2014 (see) (draft file) (animation 1) (animation 2) (animation 3) (animation 4).
  • K. Akbari Hamed, N. Sadati, W. A. Gruver, and G. A. Dumont, “Stabilization of periodic orbits for planar walking with non-instantaneous double support phase,” IEEE Transactions on Systems, Man, and Cybernetics, Part A, vol. 42, issue 3, pp. 685-706, May 2012 (see) (draft file).
  • K. Akbari Hamed, N. Sadati, W. A. Gruver, and G. A. Dumont, “Exponential stabilization of periodic orbits for running of a 3D monopedal robot,” IEE Control Theory and Applications, vol. 5, issue 11, pp. 1304-1320, July 2011 (see) (draft file).
  • K. Akbari Hamed and J. W. Grizzle, “Robust event-based stabilization of periodic orbits for hybrid systems: Application to an underactuated 3D bipedal robot,” Proceedings of the  2013 IEEE American Control Conference (ACC), Washington, DC, USA, pp. 6206-6212, June 2013 (see) (draft file) (ACC talk).
  • K. Akbari Hamed, B. G. Buss and J. W. Grizzle, Within-stride feedback laws for exponential stabilization of periodic orbits for underactuated 3D walking” in preparation, 2014. 
  • K. Akbari Hamed, B. G. Buss, and J. W. Grizzle, Continuous-time controllers for stabilizing periodic orbits of hybrid systems: Application to an underactuated  3D bipedal robot,  53rd IEEE Conference on Decision and Control (CDC 2014), under review, March 20, 2014 (draft) (Supplemental Material). 
  • A. Ramezani, J. W. Hurst, K. Akbari Hamed, and J. W. Grizzle, “Performance analysis and feedback control of ATRIAS, a 3D bipedal robot,” ASME Journal of Dynamic Systems, Measurement and Control, accepted to appear, September 2013 (see) (draft file).  
  • N. Sadati, G. A. Dumont, K. Akbari Hamed, and W. A. Gruver, “Two-level control scheme for stabilization of periodic orbits for planar monopedal running,” IEE Control Theory and Applications, vol. 5, issue 13, pp. 1528-1543, August 2011 (see(draft file).
  • R. Ansari, M. R. Feyzi, K. Akbari Hamed, N. Sadati, Y. Yasaei and S. Ouni, “Input-output linearization of a fourth-order input-affine system describing the evolution of a three-phase/switch/level (Vienna) rectifier,” IEE Power Electronics, vol. 4 , issue 8, pp. 867-883, September 2011 (see) (draft file).
  • B. G. Buss, A. Ramezani, K. Akbari Hamed, B. A. Griffin, K. S. Galloway, and J. W. Grizzle, Preliminary walking experiments with underactuated 3D bipedal robot MARLO,”  2014 IEEE/RSJ International Conference on Intelligent Robots and Systems, under review, Chicago, IL, September 2014 (draft file). 
Recent Book:
  • Hybrid Control and Motion Planning of Dynamical Legged LocomotionSeries on Systems Science and Engineering, Wiley-IEEE Press, ISBN: 978-1-118-31707-5, 272 pages, Hoboken, NJ, USA, October 2012 (see Wiley) (see IEEE Xplore(see Front matter) (see Ebook(see Google Play).


    Our Recent Experiments Directed by Prof. Grizzle  on the MARLO (ATRIAS) Project 

    Details can be found in: 

    Robustness against an external horizontal force

    Robustness against an external horizontal force


    Walking with nontrivial feet


    Walking with point feet