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.
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:
See the progress of our team directed by Prof. Grizzle on the MARLO (ATRIAS) project: