This paper investigates kinetic behavior of a planetary rover with attention to tire-soil traction mechanics and articulated body dynamics, and thereby study the control when the rover travels over natural rough terrain. Experiments are carried out with a rover test bed to observe the physical phenomena of soils and to model the traction mechanics, using the tire slip ratio as a state variable. The relationship of load-traction factor versus the slip ratio is modeled theoretically then verified by experiments, as well as specific parameters to characterize the soil are identified. A dynamic simulation model is developed considering the characteristics of wheel actuators, the mechanics of tire-soil traction, and the articulated body dynamics of a suspension mechanism. Simulations are carried out to be compared with the corresponding experimental data and verified to represent the physical behavior of a rover. Finally, a control method is proposed and tested. The proposed method keeps the slip ratio within a small value and limits excessive tire force, so that the rover can successfully traverse over the obstacle without digging the soil or being stuck.

Date Published: 17 July 2002
PDF: 12 pages
Proc. SPIE 4715, Unmanned Ground Vehicle Technology IV, (17 July 2002); doi: 10.1117/12.474459

Published in SPIE Proceedings Vol. 4715:
Unmanned Ground Vehicle Technology IV
Grant R. Gerhart; Chuck M. Shoemaker; Douglas W. Gage, Editor(s)