Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
  • G01S15/88—Sonar systems specially adapted for specific applications
  • G01S15/93—Sonar systems specially adapted for specific applications for anti-collision purposes
  • G01S15/931—Sonar systems specially adapted for specific applications for anti-collision purposes of land vehicles
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
  • G01S15/87—Combinations of sonar systems
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
  • G01S7/521—Constructional features
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
  • G01S15/88—Sonar systems specially adapted for specific applications
  • G01S15/93—Sonar systems specially adapted for specific applications for anti-collision purposes
  • G01S15/931—Sonar systems specially adapted for specific applications for anti-collision purposes of land vehicles
  • G01S2015/937—Sonar systems specially adapted for specific applications for anti-collision purposes of land vehicles sensor installation details
  • G01S2015/938—Sonar systems specially adapted for specific applications for anti-collision purposes of land vehicles sensor installation details in the bumper area
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S367/00—Communications, electrical: acoustic wave systems and devices
  • Y10S367/909—Collision avoidance

Definitions

• Method and device for detecting objects in particular as a parking assistance device in a motor vehicle
• the invention relates to a method and a device for detecting objects, in particular as a parking assistance device in a motor vehicle, comprising a number of distance sensors, at least one microcontroller controlling the distance sensors and an output unit.
• Ultrasonic sensors are particularly useful in the close range because of their very high resolution.
• Such a device is known for example from DE 44 25 419 C1, with a rear transmitter and receiver arrangement, a front transmitter and receiver arrangement, which comprises at least one transmitter and receiver unit in the middle front area and one transmitter and receiver unit in the front corner areas , a control unit for activating and deactivating the transmitter and receiver arrangement and acoustic and / or optical warning elements which, in the case of activated transmitter and receiver arrangements, generate warning signals dependent on their output signals, the front and rear transmitter and receiver arrangements being activated as long as the Reverse gear is active and the vehicle speed does not exceed a first threshold.
• the transmitter and receiver arrangement on the front is activated as long as the reverse gear is not active and the driving speed does not exceed a predetermined second threshold value. In all other driving conditions, both transmitter and receiver arrangements are deactivated.
• the distance measurement using ultrasonic transducers as a parking aid or for the detection of side obstacles in motor vehicles is based on the measurement of the travel time of the sound.
• a converter attached to the motor vehicle sends out a signal which is sent to a Obstacle is reflected. This echo can be received by further transducers mounted on the motor vehicle.
• the running time of the short wave train results directly from the time of its arrival at the receiver.
• the transit time measurement is carried out by correlating the transmitted and the received signal.
• the invention is therefore based on the technical problem of creating a method and a device for detecting objects in which the influences of other sources on the measurement accuracy are avoided.
• each sensor being given a sensor-specific identifier or the sensors being grouped together. It is also possible to have the sensors work in groups on different carrier frequencies.
• the distance sensors are preferably designed as ultrasound transducers, especially as foil ultrasound transducers, since they can be operated in a further frequency range and have good resolution.
• 1 is a schematic block diagram of the device for detecting objects with ultrasonic transducers
• FIG. 3 shows a cross section through a film sandwich ultrasound transducer
• 4a shows the amplitude characteristic for a 12 ⁇ m film ultrasound transducer
• Fig. 6 is a schematic representation of the reception situation
• Fig. 7 is a schematic representation of the determination of the distance of an object
• the device 1 for detecting objects comprises a microcontroller 2, a power supply 3, a plurality of ultrasonic transducers 4, a transmit / receive circuit 5 assigned to the respective ultrasonic transducers 4 and an optical and / or acoustic warning device 6.
• the microcontroller 2 has different functions. On the one hand, this imprints a time-variable identifier on the transmission signals of the ultrasound transducers 4 and, on the other hand, it evaluates the received signals the ultrasonic transducer 4 after the runtime and determines the distances between objects. The imprint of the identifier and the evaluation will be described in detail later. Furthermore, the microcontroller 2 controls the optical and / or acoustic warning device 6.
• This can be designed, for example, as a display on which the current distance to the objects is shown alphanumerically.
• the distance can be output acoustically by means of a speech output unit or by means of signal tones of different frequency and / or volume.
• the sequence control will now be explained by way of example for a transmit / receive circuit 5 and an ultrasound transducer 4 with reference to FIG. 2.
• the transmit / receive circuit 5 comprises a transmit amplifier 7, a series resistor 8, a decoupling capacitor 9, an amplitude limiter 10, an amplifier 11, a demodulator 12 and a signal detection unit 13. If the device 1 is now activated, the microcontroller 2 embosses the ultrasound Converter 4 has a transmission signal with a time-variable identifier, for which purpose the microcontroller 2 generates a corresponding electrical signal 14 and supplies it to the transmission amplifier 7. Depending on the type of electrical signal 14 to be used, microcontroller 2 generates signal 14 directly or by means of a function generator or a modulatable oscillator.
• This electronic signal 14 is amplified by the transmission amplifier 7 and excites the ultrasound transducer 4 due to the changing electrical field to emit ultrasound waves in accordance with the frequency spectra of the electrical signal 14.
• the voltage supply 3 supplies the operating voltage for both the transmitter amplifier 7 and for the ultrasound transducer 4.
• the resistor 8 provides a bias on the transducer 4 and is so large that the electrical charge on the transducer 4 remains almost constant in the receiving mode, so that when an ultrasonic wave is received at the transducer 4, an electrical signal arises from the change in its capacitance, which is fed to the input of the amplitude limiter 10, the decoupling capacitor 9 causing DC decoupling from the input amplifier 7 or the ultrasonic transducer 4.
• the amplitude-limited AC signal at the output of the amplitude limiter 10 is amplified by the amplifier 1 1 and demodulated in the demodulator 12, i.e. the identifier of the received signal is separated. Since the change in the identifier of the transmission signal over time is known, a comparison can be used to check whether the received signal is an echo of the transmission signal or comes from another ultrasound source.
• the film sandwich ultrasound transducer 4 comprises a conductive and preferably colored one Cover film 15, a structured spacer film 16, a transducer electrode 17 and a plastic bumper 18 or side impact protection.
• a film sandwich ultrasound transducer 4 is thus optically optimally adapted to the body of a motor vehicle and is barely perceptible.
• the transducer electrode 16 is designed, for example, as a conductive lacquer. Instead of the structured spacer film 16, the distance can also be realized by means of a structure produced by screen printing.
• foil ultrasound transducers 4 over other transducers is the large frequency range in which they can work.
• 4a shows, for example, the reception amplitude of an echo signal over the frequency for a film-ultrasound transducer 4 with a 12 ⁇ m film at an object distance of 1.40 m with a smooth surface, the reception amplitude at the resonance frequency being 0 dB was standardized. As can be seen from the illustration, the reception amplitude is attenuated over a wide frequency range less than 10 dB in relation to the resonance.
• 4b shows the reception amplitude for a film-ultrasound transducer 4 with a 24 ⁇ m film under the same measurement conditions.
• the electrical signal 14 is preferably modulated in order to impress the various, time-variable identifier, in principle all types of modulation known from communications technology being considered.
• the carrier signal to be modulated that is to say the fundamental frequency on which the ultrasound transducer 4 transmits, consists of wave trains, the modulation being able to take place within one wave train or over several wave trains, depending on the type of modulation selected.
• FIG. 5a shows an amplitude modulation within a wave train and in FIG. 5b an amplitude modulation over several wave trains.
• the reception amplitudes must always be evaluated relative to one another. Furthermore, it is necessary to amplify the received signal with an amplitude control amplifier (AGC) in order to avoid that the signal is amplified to the limit and thus the amplitude formation is lost. To increase the signal-to-noise ratio, it is also necessary to limit the frequency bandwidth.
• AGC amplitude control amplifier
• Frequency modulation is also possible both within a wave train (FIG. 5c) and over several wave trains (FIG. 5d).
• the received signal can be amplified to the limit, since the information lies in the signal frequency.
• Demodulation takes place by high-quality bandpass filters or generally by frequency analysis. It should be noted that frequency shifts occur due to relative movements of the obstacles (Ooppler effect). The frequency swing of the modulation must be greater than such a frequency shift for safe operation.
• the phase modulation is only practicable within a wave train (FIG. 5e), since the basic phase position of the input signal varies with the distance to the obstacle and therefore only a relative phase position or change in phase can be evaluated.
• the pulse length modulation (FIG. 5f) and the pulse pause modulation (FIG. 5g) change the length or the distance of several wave trains. It should be noted that the length and especially the distance of the wave trains are changed by a relative movement of the obstacle. Some of the modulation types mentioned can also be combined.
• identifiers are preferably chosen randomly and varied in order to rule out that two systems have the same identifier. If an interference signal is now received from another motor vehicle, the measurement can be declared invalid on the basis of the unknown identifier. If two signals are superimposed on the receiver, the identifier is destroyed, which is also recognized. A valid measurement is not possible during such a fault. For this reason, the transmission of signals should also be interrupted for a certain time in order to allow the other system to carry out valid measurements. So that two systems do not suspend their measurements at the same time and then interfere again, the waiting time should also be random.
• an additional identifier is modulated onto the transmission signals that have different carrier frequencies. So that a separate identifier does not have to be assigned to each vehicle, it should be changed randomly during operation. If two systems are now transmitting on the same frequency and there is mutual interference, this is recognized and the systems change their transmission frequency. The new transmission frequency should be chosen at random to prevent both systems from working again with the same transmission frequency.
• FIGS. 6 and 7 show the determination of the distance and the position of an object 19.
• FIGS. 6 and 7. Assuming that eight ultrasound transducers can transmit and receive 4 ultrasound waves, there are 64 possible running routes. 6 shows the seventh ultrasound transducer 4 in transmission mode and two of eight possible routes to the first and fourth ultrasound transducers 4. The most likely location of the object 19 results from the superposition of up to 64 ellipse equations, which is shown in FIG. 7 for the two running routes from FIG. 6.

Landscapes

• Engineering & Computer Science (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Physics & Mathematics (AREA)
• Computer Networks & Wireless Communication (AREA)
• General Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
• Electric Propulsion And Braking For Vehicles (AREA)
• Traffic Control Systems (AREA)

Priority Applications (6)

Applications Claiming Priority (4)

Related Child Applications (3)

Publications (1)

Family

ID=26047974

Family Applications (1)

Country Status (6)

Cited By (7)

Families Citing this family (33)

Citations (4)

Family Cites Families (15)

• 1999
  • 1999-07-21 EP EP99936612A patent/EP1105749B1/de not_active Expired - Lifetime
  • 1999-07-21 US US09/762,456 patent/US6690616B1/en not_active Expired - Lifetime
  • 1999-07-21 ES ES99936612T patent/ES2176007T3/es not_active Expired - Lifetime
  • 1999-07-21 AT AT99936612T patent/ATE217093T1/de not_active IP Right Cessation
  • 1999-07-21 WO PCT/EP1999/005378 patent/WO2000008484A1/de not_active Ceased
  • 1999-07-21 JP JP2000564065A patent/JP2002522773A/ja active Pending
• 2003
  • 2003-08-22 US US10/646,920 patent/US7027356B2/en not_active Expired - Lifetime

Patent Citations (4)

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