As unmanned electric wheeled mobile robots have been increasingly applied to high-speed operations in unknown environments, the wheel slip becomes a problem when the robot is either accelerating, decelerating, or turning at high speed. Ignoring the effect of wheel slip may cause the mobile robot to deviate from the desired path. In this paper a recently proposed method is implemented to estimate the surface conditions encountered by an unmanned wheeled mobile robot, without using extra sensors. The method is simple, economical and needs less processing power than for other methods. A reaction torque observer is used to obtain the rolling resistance torque and it is applied to a wheeled mobile robot to obtain the surface condition in real-time for each wheel. The slip information is observed by comparing the reaction torque of each wheel. The obtained slip information is then used to control the torque of both wheels using a torque controller. Wheel slip is minimized by controlling the torque of each wheel. Minimizing the slip improves the ability of the unmanned electric wheeled mobile robot to navigate in the desired path in an unknown environment, regardless of the nature of the surface.