| A six-wheeled autonomous omni-directional vehicle (ODV) called T3 has been developed at Utah State University's (USU) Center for Self-Organizing and Intelligent Systems (CSOIS). This paper focuses on T3's ability to climb stairs using its unique configuration of six independently driven and steered wheels and active suspension height control. Stability criterion is developed for any vehicle dimensions and orientation, on any staircase. Method of optimizing vehicle approach angles is presented. Controllers are investigated for controlling vertical wheel movement with the objective of maintaining optimum chassis pitch and roll angles. A controller is presented that uses feedback from wheel loading, vertical wheel position, and chassis orientation sensors. The implementation of the controller is described, and T3's stair climbing performance is presented and evaluated. Abilities and limitations of current hardware and algorithms are identified along with suggestions for future improvements. |
