• 제어로봇시스템학회논문지
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• 제14권10호
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• pp.1062-1072
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• 2008

When mobile robots perform the mission in the rough terrain, the traversability depended on the terrain characteristic is useful information. In the traversabilities, wheel-terrain maximum friction coefficient can indicate the index to control wheel-terrain traction force or whether mobile robots to go or not. This paper proposes estimating wheel-terrain maximum friction coefficient. The existing method to estimate the maximum friction coefficient is limited in flat terrain or relatively easy driving knowing wheel absolute velocity. But this algorithm is applicable in rough terrain where a lot of slip occurred not knowing wheel absolute velocity. This algorithm applies the tire-friction model to each wheel to express the behavior of wheel friction and classifies slip-friction characteristic into 3 major cases. In each case, the specific algorithm to estimate the maximum friction coefficient is applied. To test the proposed algorithm's feasibility, test bed(ROBHAZ-6WHEEL) simulations are performed. And then the experiment to estimate the maximum friction coefficient of the test bed is performed. To compare the estimated value with the real, we measure the real maximum friction coefficient. As a result of the experiment, the proposed algorithm has high accuracy in estimating the maximum friction coefficient.

• Journal of Biosystems Engineering
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• 제26권1호
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• pp.1-10
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• 2001

Interactions between cage wheel and soil under the wet paddy field condition were analyzed. The cage wheel as a traction aid to driving tires of tractor was attached to the outside of the tires. The driving torque transmitted only to the cage wheel was measured and its effect on the total driving torque by both the tires and cage wheel was analyzed. Mathematical models were developed to predict the soil thrusts y a single lug and by the cage wheel with many lugs, respectively. Experimental results showed that as the diameter of cage wheel increased, positive effects of the cage wheel on the traction also increased. About 33-40% of the total traction force was obtained by the cage wheel with a diameter 1,182mm and 49-55% with a diameter 1,222mm. The peak thrust of the single lug of cage wheel increased by 31% and 59%, respectively when the diameter of the cage wheel increased from 1,182mm to 1,222mm and 1,262mm. The thrust by the cage wheel was estimated by using the developed mathematical models and the results were proved that the models are reliable for the estimation of the traction by the cage wheels.