A method of negotiating an obstacle including driving an articulated vehicle along a drive direction over a surface, driving the articulated vehicle to approach an obstacle with a rearward portion of the articulated vehicle, pivoting arms of the vehicle from a stowed position next to a main frame of the vehicle downward and away from the main frame, raising and supporting the main frame on the arms, positioning at least a portion of the main frame substantially against the obstacle, and driving onto the obstacle.