@Override
    public void update(float tpf) {
        if (enabled && spatial != null) {
            if (getMotionState().applyTransform(spatial)) {
                spatial.getWorldTransform();
                applyWheelTransforms();
            }
        } else if (enabled) {
            applyWheelTransforms();
        }
    }
Update this control. Invoked once per frame, during the logical-state
update, provided the control is added to a scene.

@param tpf the time interval between frames (in seconds, &ge;0)
jme3-jbullet/src/main/java/com/jme3/bullet/control/VehicleControl.java