Navigator interface

A self-propelled guide unit configured to connect to and guide a self-propelled load bearing unit, such that the self-propelled load bearing unit can travel on a floor surface when the self-propelled guide unit and the self-propelled load bearing unit are connected, the self-propelled guide unit being configured to:

• receive at least one parameter from the self-propelled load bearing unit,
• use the at least one parameter in the generation of a control signal, and
• transmit the generated control signal to the self-propelled load bearing unit for controlling the propulsion of the self-propelled load bearing unit, the self-propelled guide unit comprises:
• at least one engaging element configured to engage at least one corresponding engaging element on the self-propelled load bearing unit,
• at least one drive wheel configured to propel the self-propelled guide unit on the floor surface, and
• wherein the self-propelled guide unit is configured to lift itself from the floor surface by the steps:
• moving the at least one drive wheel in a direction away from the floor surface,
• having the at least one engaging element engage the at least one corresponding engaging element on the self-propelled load bearing unit,
• continuing to move the at least one drive wheel in a direction away from the floor surface such that the at least one engaging element carries a portion of the weight of the self-propelled guide unit.