PhD Dissertation Presentation
Monday, June 30, 2008
9:30 am
2555 D Engineering Bldg.
(Mechanical Engineering Conference Room)“Adaptive Control Subject to Input Constraints: Maneuvering Wheeled Platforms Using a Holonomic Mobile Robot”
by
Nandagopal Methil-Sudhakaran
Advisor: Dr. Ranjan Mukherjee
The problem of adaptive control in the presence of input constraints is studied in the context of a holonomic mobile robot pushing and steering a wheelchair using a single manipulator. Adaptive control is employed to estimate, in real time, the inertia characteristics of the wheelchair and its occupant, and friction between the wheelchair and the surface that it traverses. The input constraints considered are actuator saturation and actuator dynamics. Saturation of control input limits the maximum input that can be provided to the system and input actuator dynamics dictate the speed with which the control input can be realized. If left unaddressed, these constraints can result in poor tracking performance and/or instability. The control designs presented here complement the mechanical design of the manipulator such that a holonomic mobile robot employing the manipulator can maneuver a wheelchair asymptotically along a reference trajectory. The results are however subject to certain practical requirements on the reference trajectories. The reference trajectories can be generated autonomously or provided by a human operator and in this context, preliminary designs of haptic devices have been explored. Overall, this work has the potential to provide greater mobility to residents of Long Term Care facilities, which are currently experiencing an acute shortage of nurses and an increasing number of inmates. The concepts developed in this work can be extended to other wheeled platforms with non-holonomic constraints, such as stretchers and wheeled carts, thus providing the scope for applications in hospitals and other healthcare institutions. Experimental results employing an RP-6 mobile robot platform and a wheelchair are presented to validate the theoretical results.
Persons with disabilities please contact Aida Montalvo at montalai@egr.msu.edu to request accommodations.