AUTOMATIC MOTORWAY DRIVING SYSTEM FOR MOTOR VEHICLES

• US 3,773,136 A
• Filed: 01/14/1972
• Issued: 11/20/1973
• Est. Priority Date: 01/29/1971
• Status: Expired due to Term

• Current Assignee: Bruno Cavallarin, Mario Palazzetti
• Original Assignee: Bruno Cavallarin, Mario Palazzetti
• Inventors: Palazzetti, Mario, Cavallarin, Bruno
• Primary Examiner(s): Betts, Kenneth H.
• Assistant Examiner(s): Silverstrim, John P.
• Application Number:
  US05/217,905
• Time in Patent Office: 676 Days
• Field of Search: 180/98,79,79.1 318/587 340/104,61
• US Class Current: 180/168
• CPC Class Codes: G05D 1/0265 using buried wires

Abstract

This invention relates to an automatic motorway driving system in which passive rectangular coils are buried in a motorway, preferably in both the normal driving and overtaking lanes, for cooperation with a front transmitter loop and two rear receiver loops carried by each vehicle. Each vehicle has an alternating current generator which applies an alternating current to the transmitter loop and which scans a range of frequencies cyclically so that signals picked up through inductive linkage of the receiver loops with the buried coils can provide servo control signals indicative of the distance of preceding vehicles or the presence of overtaking vehicles. The two receiver loops symmetrically placed at opposite sides of the vehicle and electronic comparison of the signals picked-up thereby is used to control a vehicle steering servomechanism to maintain the vehicle centrally in the normal driving lane.

Claims

1. Automatic motorway driving system comprising a specially equipped motorway having a normal driving lane and an overtaking lane And vehicles having electrically controlled steering and equipped with an installation adapted to cooperate with the motorway, wherein:

the motorway is provided with a series of closed substantially rectangular conductive coils, buried beneath and parallel to the motorway surface with their long sides arranged symmetrically with respect to and parallel to the longitudinal axis of the normal driving lane of the motorway;

the vehicle installation includes an alternating voltage generator, a transmitter loop connected to the generator and disposed at the front of the vehicle on the longitudinal axis thereof, two receiver loops disposed symmetrically with respect to the longitudinal axis of the vehicle at the rear of the latter and adapted to be coupled inductively with successive coils in the normal driving lane of the motorway, and a first comparison circuit connected to the two receiver loops and comparing the amplitudes of the signals picked-up by the receiver loops to provide an output signal controlling the vehicle steering, each vehicle having a brake control servomechanism, the alternating voltage generator mounted on each vehicle generating a voltage the frequency of which increases as the vehicle passes from one end to the other of each buried coil of the normal driving lane of the motorway and in which the signal picked by one of the receiver loops is applied to detecting means which determine if such signal contains, in addition to the instantaneous transmitted frequency of the vehicle in question, also an extraneous, higher, frequency due to a preceding vehicle, said means in such case actuating said brake control servomechanism by an amount inversely proportional to the difference between the two frequencies.

2. Automatic driving system as defined in claim 1, in which the detector means include a band-stop filter having a narrow stop band connected to one of said receiver loops and controlled by the alternating voltage generator to eliminate the frequency of the signal applied to the transmitter loop at any given instant, a third comparison circuit which compares the frequency of the output signal of the band-stop filter with the said frequency of the signal applied to said transmitter loop and a gate inserted between said detecting means sensitive to the difference of frequency and the brake control servomechanism, said gate receiving an enabling signal from said third comparison circuit when the frequency of the output signal of the band-stop filter is higher than the instantaneous frequency of the signal applied to said transmitter loop of the vehicle.

3. Automatic driving system as defined in claim 1, in which said detecting means sensitive to the differene of frequency comprise a non-linear element connected to one of the receiver loops, a low-pass filter having a pass frequency equal to the maximum possible difference in frequency between the instantaneous transmission frequency of the vehicle and the said extraneous frequency, connected to the output of the non-linear element, and means applying the output of the low-pass filter to the brake control servomechanism to apply the brakes in dependence upon said frequency difference.

4. Automatic driving system as defined in claim 1, including rectifier circuits and respective low pass filters connecting each receiver loop to said first comparison circuit, and an inverter connected to the output of one of said rectifying circuits, the commencement of each frequency increase in the alternating voltage provided by the generator being controlled by the leading edge of the output signal from said inverter.

5. Automatic motorway driving system comprising a specially equipped motorway having a normal driving lane and an overtaking lane and vehicles having electrically controlled steering and equipped with an installation adapted to cooperate with the motorway, wherein:

the motorway is provided with a series of closed substantially rectangular conductive coils, buried beneath and parallel to the motorway surface with their long sides arranged symmetrically with respect to and parallel to the longitudinal axis of the normal driving lane of the motorway;

the vehicle installation includes an alternating voltage generator, a transmitter loop connected to the generator and disposed at the front of the vehicle on the longitudinal axis thereof, two receiver loops disposed symmetrically with respect to the longitudinal axis of the vehicle at the rear of the latter and adapted to be coupled inductively with successive coils in the normal driving lane of the motorway, and a first comparison circuit connected to the two receiver loops and comparing the amplitudes of the signals picked-up by the receiver loops to provide an output signal controlling the vehicle steering, the motorway also including conductive coils buried parallel to the motorway surface, aligned along the axis of the overtaking lane, said coils having a substantially rectangular shape symmetrically disposed with respect to the axis of the overtaking lane and further having a supplementary loop which extends into the gap between the adjacent ends of two coils of the normal driving lane, and including a rectifying circuit connected to one of the receiver loops, an indicator connected to the output of said rectifying circuit, a gate interposed between said rectifying circuit and said indicator, means enabling said gate in response to movement of the vehicle past the end of a said coil in the normal driving lane, said gate passing an energising signal to said indicator when the overtaking lane of the motorway is occupied, and sensitive means disabling said gate.