Intelligent slip-optimization control with traction-energy trade-off for wheeled robots on rough terrain

On rough terrain, there are a variety of soil types having different soil strength. It means that it is needed to change wheel control strategies since optimal wheel slip levels differ depending on soil strength. Therefore, this paper proposes a novel algorithm for optimal slip control of wheeled robots with a trade-off between traction and energy consumption on the basis of observing a change of a robot velocity on a variety of soil types. Proposed intelligent slip-optimization control algorithm is largely divided into three main parts; (1) slip optimization (2) slip controller (3) intelligent disturbance compensator. For slip optimization, an optimal slip model is derived as a function of slip ratios regarding maximum traction and tractive efficiency from indoor experimental data during a wheel-terrain interaction. Optimized slip ratio is used as an input of a PID slip controller with compensation of disturbance which occurs by a change of surface shapes. This algorithm is verified by controlling a real four wheeled robot on rough terrains.