wheel which is parallel with the first and at least a third supporting element which can take the form of a wheel application_number US 2277579 A description with reference to the drawings fig1 shows a self propelled mechanism 10 in the form of a vehicle that is controlled in accordance with the invention it will be appreciated that the mechanism of fig1 as well as the accompanying circuit schematic diagram of fig2 are illustrative only in addition to facilitate the understanding of the device and its operation a table of nomenclature is included at the end of this specification the self propelled vehicle 10 is formed by a chassis 11 in which are mounted parallel positioned wheels w 1 and w 2 that constitute the driving instrumentalities or elements of the device in addition the chassis is supported in the rear by a supporting element in the form of a wheel w 3 it will be apparent that the supporting element w 3 can take a wide variety of other forms and may be supplemented by additional support elements and also that the disposition of the driving wheels w 1 and w 2 shown at the front of the vehicle can be positioned in a wide variety of ways for example at the rear the driving wheels w 1 and w 2 are controlled by respective motors m 1 and m 2 the latter are in turn operated from a command module 12 which is in turn controlled by a user or operator from a control.