A base for a mobile X-ray imaging system comprises a carriage, a mounting structure mounted to the carriage and that movably holds an imaging device, a wheel base, and a controller. The wheel base comprises at least three wheels mounted to the carriage to be pivotable around a vertical pivot axis and to rotate around a horizontal wheel axis. At least two of the wheels form rearside wheels and at least one of the wheels forms a frontside wheel. Each rearside wheel is independently steerable in its orientation around the vertical pivot axis by a pivot actuator. Each rearside wheel is independently drivable around its horizontal wheel axis by a drive actuator to move the base relative to the floor. The controller steers and drives the rearside wheels.