Road surface sensing system for a vehicle

• US 5,061,932 A
• Filed: 08/06/1990
• Issued: 10/29/1991
• Est. Priority Date: 08/10/1989
• Status: Expired due to Term

• Current Assignee: Lucas Industries Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Lucas Industries Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Tribe, Raglan H. A. H., Thomson, Neil G.
• Primary Examiner(s): Barron, Jr., Gilberto
• Application Number:
  US07/562,923
• Time in Patent Office: 449 Days
• Field of Search: 342/70-72, 342/104, 73/105, 73/146
• US Class Current: 342/70
• CPC Class Codes: B60G 17/019 characterised by the type of sensor or the arrangement thereof B60G17/01941 takes precedence
• CPC Class Codes: B60G 2400/82 Ground surface
• CPC Class Codes: B60G 2401/174 Radar
• CPC Class Codes: B60G 2500/10 Damping action or damper
• CPC Class Codes: B60G 2500/30 Height or ground clearance
• CPC Class Codes: B60G 2500/42 Sensibility
• CPC Class Codes: B60G 2600/14 Differentiating means, i.e. differential control
• CPC Class Codes: B60G 2600/604 low pass
• CPC Class Codes: B60G 2800/24 Steering, cornering
• CPC Class Codes: G01S 13/60 wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track G01S13/64 takes precedence
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 13/935 for terrain-avoidance
• CPC Class Codes: G01S 2013/9318 Controlling the steering
• CPC Class Codes: G01S 2013/93185 Controlling the brakes
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/9322 using additional data, e.g. driver condition, road state or weather data
• CPC Class Codes: G01S 2013/9323 Alternative operation using light waves
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 2013/93275 in the bumper area

Abstract

A system for sensing road irregularities from a vehicle modifies an operational system of the vehicle, such as a suspension system, according to the type and severity of the sensed irregularity. The system employs a Doppler Microwave radar sensor arranged to project radiation at a road surface ahead of the vehicle and includes means for detecting radiation reflections of which the carrier frequency is amplitude modulated according to the surface irregularities. An electronic circuit differentiates the modulated signal to produce a control signal representative of said surface condition and a controller receives said signal and modifies the operation of the vehicle system in response thereto.

Claims

1. A road surface sensing system for a vehicle, said system comprising:

a transmitter for projecting electromagnetic radiation having a carrier at a road surface ahead of a vehicle; and

a receiver for receiving the electromagnetic radiation reflected by the road surface whereby the carrier of the reflected radiation is amplitude modulated according to irregularities of the road surface, said receiver comprising;

detection means for detecting an amplitude modulation signal of the carrier of the reflected radiation;

differentiating means for differentiating the amplitude modulation signal from said detection means and for producing a control signal representative of a road surface condition; and

vehicle system control means, responsive to the control signal from said differentiating means, for modifying an operating of the vehicle.

2. A system as claimed in claim 1, in which said transmitter is a microwave transmitter.

3. A system as claimed in claim 1, in which said receiver further comprises a low pass filter connected between said detection means and said differentiating means.

4. A system as claimed in claim 1, in which said vehicle system control means includes comparing means for comparing the control signal at least one threshold.

5. A system as claimed in claim 4, in which said comparing means includes discriminating means for discriminating between a positive slope and a negative slope of the amplitude modulation signal.