Title :
Experimental Evaluation of Dynamic Redundancy Resolution in a Nonholonomic Wheeled Mobile Manipulator
Author :
White, Glenn D. ; Bhatt, Rajankumar M. ; Tang, Chin Pei ; Krovi, Venkat N.
Author_Institution :
Gen. Motors, Honeoye Falls, NY
fDate :
6/1/2009 12:00:00 AM
Abstract :
Mobile manipulators derive significant novel capabilities for enhanced interactions with the world by merging mobility with manipulation. However, a careful resolution of the redundancy and active control of the reconfigurability, created by the surplus articulated DOFs and actuation, are the keys to unlocking this potential. Nonholonomic wheeled mobile manipulators, formed by mounting manipulator arms on disc-wheeled mobile bases, are a small but important subclass of mobile manipulators. The primary control challenges arise due to the dynamic-level coupling of the nonholonomy of the wheeled mobile bases with the inherent kinematic and actuation redundancy within the articulated chain. The solution approach in this paper builds upon a dynamically consistent and decoupled partitioning of the articulated system dynamics between the external (task) space and internal (null) space. The independent controllers, developed within each decoupled space, facilitate active internal reconfiguration, in addition to resolving redundancy at the dynamic level. Specifically, two variants of null-space controllers are implemented to improve disturbance rejection and active reconfiguration during performance of end-effector tasks by a primary end-effector impedance mode controller. These algorithms are evaluated within an implementation framework that emphasizes both virtual prototyping and hardware-in-the-loop testing with representative case studies.
Keywords :
manipulator dynamics; manipulator kinematics; mobile robots; motion control; wheels; articulated system dynamics; dynamic redundancy resolution; impedance mode controller; inherent kinematic redundancy; manipulator arm; motion control; nonholonomic wheeled mobile manipulator; Aerodynamics; Arm; Impedance; Kinematics; Manipulator dynamics; Merging; Robots; Robustness; Testing; Virtual prototyping; Dynamic redundancy resolution; hardware-in-the-loop (HIL); nonholonomic wheeled mobile manipulator (NH-WMM); virtual prototyping (VP);
Journal_Title :
Mechatronics, IEEE/ASME Transactions on
DOI :
10.1109/TMECH.2008.2008802