Umashankar Nagarajan

About

Umashankar Nagarajan is a robotics researcher whose work centers on dynamically stable mobile robots, motion planning, and human-robot interaction. He is best known for his foundational contributions to the ballbot—a human-sized mobile robot that balances on a single spherical wheel—addressing key challenges in state transition, balancing, yaw control, and omnidirectional movement. His most-cited work, "The Ballbot: An Omnidirectional Balancing Mobile Robot" (2013, 120 citations), along with complementary papers on trajectory planning and underactuated control (each exceeding 100 citations), established critical theoretical and experimental frameworks for dynamically stable robotic platforms. Nagarajan further extended this research into high-dimensional shape space planning for robots with arms, introducing the concept of "shape-accelerated balancing systems" to elegantly handle complex underactuated dynamics. Beyond balancing robots, he has contributed to humanoid robot safety through fall control strategies and, more recently, to practical mobile manipulation systems capable of one-shot learning of complex household tasks. With a body of work accumulating nearly 500 citations, his research meaningfully bridges advanced control theory and real-world robotic deployment in human environments, making him a notable figure in mobile robotics and autonomous systems.

Research Focus

Key Achievements

Top Papers

1. 1
   The ballbot: An omnidirectional balancing mobile robot

   120 citations · 2013
2. 2
   State transition, balancing, station keeping, and yaw control for a dynamically stable single spherical wheel mobile robot

   105 citations · 2009
3. 3
   Trajectory planning and control of an underactuated dynamically stable single spherical wheeled mobile robot

   101 citations · 2009
4. 4
   Direction-changing fall control of humanoid robots: theory and experiments

   43 citations · 2013
5. 5
   Planning in high-dimensional shape space for a single-wheeled balancing mobile robot with arms

   26 citations · 2012
6. 6
   A Mobile Manipulation System for One-Shot Teaching of Complex Tasks in Homes

   21 citations · 2020
7. 7
   Generalized direction changing fall control of humanoid robots among multiple objects

   20 citations · 2010
8. 8
   Human-robot physical interaction with dynamically stable mobile robots

   19 citations · 2009
9. 9
   Shape space planner for shape-accelerated balancing mobile robots

   19 citations · 2013
10. 10
    Integrated motion planning and control for graceful balancing mobile robots

    15 citations · 2013

Key Collaborators

Contact & Links