Communications: electrical – Land vehicle alarms or indicators – Of relative distance from an obstacle
Reexamination Certificate
1999-04-19
2001-08-28
Swarthout, Brent A. (Department: 2736)
Communications: electrical
Land vehicle alarms or indicators
Of relative distance from an obstacle
C340S903000, C340S943000, C367S909000
Reexamination Certificate
active
06281786
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to an obstacle detection system for a vehicle.
2. Description of the Prior Art
U.S. Pat. No. 5,717,399 discloses an obstacle detection system for vehicle use which utilizes a plurality of electromagnetic antennas for transmitting FM radio waves and receiving reflected radio waves for detection of nearby objects as well as remote objects in order to cover a wide detection range. In view of the known fact that the electromagnetic antenna has only insufficient detection capability for detection of nearby objects, particularly due to its narrow directivity, it is necessary to provide a plurality of the electromagnetic antennas within a single radar module for covering a wide detection angle for the nearby object as contemplated in the above patent, or to add a scanning mechanism to the single electromagnetic antenna for covering the wide detection angle. However, this involves additional and complex circuit configurations or mechanical structures with attendant cost increase for manufacture of the system. Further, when the plurality of the differently oriented electromagnetic antennas are combined into the one radar module for detection of the nearby objects over a wide angular detection zone, the individual antennas have to be activated sequentially to monitor individual areas one by one within the detection zone. However, there is always a problem with this detection method that the nearby object is only detected at the last of the sequence, causing a delay in detection response.
SUMMARY OF THE INVENTION
The present invention has been accomplished in view of the above problems to provide an improved obstacle detection system for a vehicle which is capable of detecting nearby and remote objects successfully by use of a combination of electromagnetic wave and ultrasonic wave sensors. The system of the present invention includes a plurality of the ultrasonic wave sensors each of which transmits an ultrasonic wave around the vehicle and receives a reflected ultrasonic wave thereof for detection of nearby obstacles around the vehicle, and an electromagnetic wave sensor which transmits an electromagnetic wave in a forward direction of the vehicle and receives a reflected electromagnetic wave thereof for detection of the remote obstacle. The system includes a vehicle speed sensor is provided for sensing a speed of the vehicle and provides a speed output indicative thereof. Also included in the system is a detection unit which detects a presence of the nearby obstacle based upon the reflected ultrasonic wave when the speed output is not more than a predetermined reference speed, and detects a position of the remote obstacle relative to the vehicle only based upon the reflected electromagnetic wave when the speed output exceeds the reference speed. The detection unit issues a nearby signal upon detection of the nearby obstacle and issues a remote signal when the position of the remote obstacle is within a predetermined long distance from the vehicle. A warning unit is also provided to give warnings respectively in response to the nearby and remote signals. Thus, the system utilizes the ultrasonic sensor which is known to have good sensitivity for detection of the nearby obstacle and the electromagnetic sensor known to have good sensitivity for detection of the remote obstacle, thereby covering a wide detection range with sufficient and reliable sensitivity and with a simple circuit configuration.
Preferably, the detection unit is configured to shorten the predetermined long distance for narrowing a detection range of the remote obstacle as the speed output is lowered, thereby eliminating unnecessary detection of a far remote obstacle when the vehicle is traveling at a relatively low speed.
The system is also preferred to include a direction sensor which provides a steering wheel angle of the vehicle so that the electromagnetic wave sensor varies its wave transmission direction or directivity depending upon the steering wheel angle for reliable detection of the remote obstacle located in an actual course that the vehicle is intended to proceed.
Further, the system may includes a rear electromagnetic wave sensor unit which transmits an electromagnetic wave in a rearward direction of the vehicle and receives a reflected electromagnetic wave thereof for detecting a remote obstacle behind the vehicle. The detection unit processes the reflected electromagnetic wave from the rear electromagnetic wave sensor to detect a position of the remote obstacle behind the vehicle and to discriminate the remote obstacle as another vehicle approaching from behind when the position of the remote obstacle is found to become closer to the vehicle and to issue a catching-up signal indicative of the presence of the catching-up vehicle. The warning unit responds to the catching-up signal for generating a warning for assuring a safe driving.
The warning unit may comprise a buzzer generating an intermittent buzzing sound of which interval and/or frequency varies according to the detection of the nearby and remote obstacles.
Alternatively, the warning unit may comprise a voice speaker which generates a voice message for the detection of the nearby and remote obstacles.
These and still other objects and advantageous features of the present invention will become more apparent from the following description of the preferred embodiment of the present invention when taken in conjunction with the attached drawings.
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patent: 5530651 (1996-06-01), Uemura et al.
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patent: 5717399 (1998-02-01), Urabe et al.
patent: 5831717 (1998-11-01), Ikebuchi
patent: 5872508 (1999-02-01), Taoka
patent: 5940011 (1999-08-01), Agravante et al.
patent: 2309555 (1997-07-01), None
Adachi Kenichi
Azuma Naoya
Greenblum & Bernstein P.L.C.
Matsushita Electric & Works Ltd.
Swarthout Brent A.
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