Idea for Guard to Prevent Robot Vacuums from Getting Stuck Under Furniture

Robot vacuums invariably get stuck under some piece of furniture (often couches). Solution--an adjustable-height "visor" along the front perimeter, to prevent the robot from going under the problem furniture that is going to get it stuck.

I guess a complication is that it is not enough for the visor to extend upwards, preventing entrance. That might just cause the unit to stall. It needs to extend down, over the bumper, which is what prompts the unit to redirect when it hits an obstacle.

Although I think there is a software fix. If the unit is not moving for 10 seconds, even if the bumper is not activated, assume it has hit an obstacle, and change direction.