Communications: electrical – External condition vehicle-mounted indicator or alarm – Transmitter in another vehicle
Patent
1995-05-19
1997-02-11
Hofsass, Jeffery
Communications: electrical
External condition vehicle-mounted indicator or alarm
Transmitter in another vehicle
340435, 340436, 340904, 367 99, 367909, G08G 116
Patent
active
056025424
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a circuit arrangement for a motor vehicle having an ultrasonic sensor and an evaluation circuit to determine the distance of a motor vehicle from an obstacle. A circuit arrangement for the determination and display of the undershooting of predetermined minimum distances between a vehicle and an obstacle is already known from EP 48 958 B1. In the circuit arrangement, used as a parking aid, an ultrasonic sensor transmits sound waves and measures the transit time of the echo reflected from an obstacle. In this arrangement, the measurement of the distance from the obstacle is sufficiently precise only during the approach to an obstacle as far as to a specific minimum value, since the sensor cannot register every contour in the case of a very small distance from obstacles, for example from the fender of the vehicle. This leads to the measurement being aborted or no longer displayed, on safety grounds, at a distance of a few centimeters. In practice, this leads to a relatively large amount of parking space being wasted during parking.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a parking aid with a wheel sensor, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a circuit arrangement for a motor vehicle having an ultrasonic sensor, an evaluation circuit and a warning display for an output of a distance of a vehicle from an obstacle, wherein also at least one displacement sensor is provided and the evaluation circuit has means for determining a distance in an immediate near range of the motor vehicle from the signals of the displacement sensor, and the means is formed to determine the distance above a predetermined limiting value, by an ultrasonic transit time measurement.
When the device is designed in accordance with the present invention, it has the advantage that the distance from the vehicle contour can be registered with sufficient precision to a value close to 0 cm.
By means of the measures listed in the dependent claims, advantageous further developments and improvements of the circuit arrangement specified in the main is particularly advantageous that the measurement of the distance above a predetermined limiting value is carried out by means of ultrasonic measurement. This measurement is independent of steering movements and hence always registers the shortest distance from an obstacle. Below the predetermined limiting value, on the other hand, the distance determination is carried out using the measured values of the displacement sensor.
By comparing the measurement contour (=obstacle contour) with the stored vehicle contour, the shortest distance from an obstacle is advantageously registered. In consequence, obstacles located at the vehicle edge are also included in the evaluation. Furthermore, it is particularly advantageous that, as a result of the double measurement of the distance by means of the ultrasonic sensor and the comparison with a defined travel distance, which is measured by the displacement sensor, a calibration for the distance measurement can be carried out. By means of simple averaging, a correction factor can be formed which corrects the distance value for the corresponding measuring range. In this case, the correction can advantageously be carried out in such a way that a minimum distance is assessed, on safety grounds.
An advantageous application of the distance measurement is given in the case of a parking aid which can be used as a parking aid or an unparking aid.
Furthermore, it is advantageous to activate the display or the parking aid only at low speeds. At greater speeds, greater distances are also maintained, so that a measurement of short distances is no longer necessary. This threshold can be defined dynamically by means of the ABS sensors.
The novel features which are considered as characteristic for the invention a
REFERENCES:
patent: 4537271 (1985-08-01), Ito et al.
patent: 4567747 (1986-02-01), Matay
patent: 4694296 (1987-09-01), Sasaki et al.
patent: 4778023 (1988-10-01), Sugasawa
patent: 4908704 (1990-03-01), Fujioka et al.
patent: 5153559 (1992-10-01), Atsumi
patent: 5212467 (1993-05-01), Park
patent: 5214408 (1993-05-01), Asayama
patent: 5220536 (1993-06-01), Stringe et al.
patent: 5330226 (1994-07-01), Gentry et al.
patent: 5386285 (1995-01-01), Asayama
Hofsass Jeffery
Robert & Bosch GmbH
Striker Michael J.
Trieu Van T.
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