ELECTROMAGNETIC DETECTION SYSTEM FOR PARKING OPERATION

Abstract: An electromagnetic detection system mainly for signalizing not visible obstacles during vehicle parking operation. The system comprises a transmitting-receiving mean (F) of radiofrequency field consisting of two wires or strips of electrically conductive material (antenna) coupled together; a mean (T) capable of creating, all around said transmitting-receiving mean, an electromagnetic radiofrequency field; a mean (R) capable of detecting the variations of said electromagnetic field produced by an object approaching the said transmitting-receiving mean; a mean (S) capable of signalizing such variations with an acoustic or view signal. Advantages: detection of the obstacles approaching the vehicle with absolute continuity for all the extension of the part which has to be protected (for example the bumper); detection of the obstacles not depending on their physical properties as shape, dimensions, density and reflective property, continuity of the obstacles detection from the maximum detection distance up to the contact without the blind zone (30-40 centimeters before the contact) which characterizes the prior art systems.

Description: TITLE : Electromagnetic detection system for parking operation . * * * * * This invention relates to a system able to provide a alarm signal indicative of the presence of any kind of obstacles in proximity of the part of the vehicle .which has to be protected. The application of this system becomes very usefull durin parking operation and mainly for protecting the back part of the vehicle the most difficult to control from the driver seat. It is known, in the applicable art, to employ different systems for use in vehicles control during parking operation. These systems include means vhich detect approachin obstacles by monitoring with acoustic or view signals in all the cases in which the direct perception of the driver is difficult or impossible. It is possible to mention some examples of prior art for use with the same purpose to which the present invention relates. For example, U.S. Pat. No. 4.278.962, is based on the us of transmitting and receiving means of ultrasonic waves . In this case the electronic system includes one or more transmitting- receiving transducers mounted outside the vehicle bumper and a electronic unit, electricaly connected to them, which provides t decode the acoustic waves reflected by obstacles in proximity of the vehicle and to signalize approximately the distance by digital or analogic means. Such a system is nevertheless not always able to recogniz the real distance between the ultrasonic transdoucer and th detected obstacle because the ammount of reflected ultrasonic waves ( one of the parameters on which is based the distanc measuring system ) is depending on the shape .density an reflective property of the obstacle. Furthermore the ultrasonic system is unable to detect obstacles which are closer than 30- 40 centimeters owing to the phisical limits of the system which is based on the measurement of the time employed by the acoustic waves to return after reflection. It is also known that the detection field, when using ultrasonic system, has a conical shaped configuration and for this reason it is not able to protect, for example, the bumper surface for all his extension but only with an angled limitation departing from the acoustic transdouce . For this reason, in order to obtain more complete protection, it is necessary the use of more than one acoustic transdouce . In addition, the prior art ultrasonic system need the use of external sensors (acoustic transdoucerε) which are visible and susceptible of handling and damage ent. Furthermore the ultrasonic system is relatively expensive in his components (electronic unit, ultrasonic transdoucers) . Is the object of the present invention to overcome the problems of the prior art and to provide a practical obstacles detection system, mainly for vehicles, of low cost, easy installation, not visible outside the vehicle and ablε to give an alarm signal when the obstacle is approaching the part of the vehicle which has to be protected, with the following benefits: Detection of the obstacles approaching the vehicle with absolute continuity for all the extension of the part which has to be protected (for example the bumper). - Detection of the obstacles not depending on theyr phisical proprieties as shape, dimensions,density and reflective propriety. Continuity of the obstacles detection from the maximu detection distance up to the contact without the blind zone (30-40 centimeters before the contact) which characterizes the prior art systems. - Increment of the detection sensitivity as shorter is the obstacle distance which guarantees a more prompt alarm signal fo very short approaching movements in the close proximity. Low cost. For this purpose, according to the present invention, th electromagnetic detection system is characterized in that i employs, in his preferred embodiment, a transmitting-receivin mean consisting of two wires or strps of electrical conductiv material (antennas) coupled together; a mean capable of generatin an electromagnetic field (near field) of radio frequency al around this transmitting-receiving mean; a mean capable o detecting (demodulate) the variations of said electromagneti field caused by an object which is approaching to sai transmitting-receiving mean; a mean giving an acoustic or wie alarm signal in presence of such electromagnetic field variation. The invention will now be described, in his preferre embodiment, in more details with reference to the accompanyin drawings, in which: Fig. 1 is a general block diagram of the apparatus of th preferred embodiment of the invention. Fig. 2 is an electrical circuit schematic diagram of th apparatus of the preferred embodiment of the invention. Fig. 3 shows an example of automotive installation of th system, object of the present invention, for use as vehicl parking control in the back side of the vehicle. Fig 4,5 and 6 show respectively the diagrammati configuration of the section view, the side view and the uppe view of the electromagnetic detection field generated around th car bumper when employing the preferred embodiment of the present invention used as parking control. Referring now to these enclosed drawings, the apparatu employing the system object of the present invention is mainl composed, in his preferred embodiment, of two parts: one electronic units M and one electromgnetάc radio frequency fiel F, In more details, in Fig. 1, At symbolizes the transmittin antenna connected with the radio frequency oscillator T and A simbolyzes the receiving antenna connected with the revealatio device R, A simbolyzes the signal amplifier and S the acousti module for alarm signal. The electrical circuit of Fig. 2 is a preferre application example of the general block diagram of Fig.l. In i the transmitting-receiving mean is constituted by two simpl coupled electrical wires like, for example, a Television fla antenna 300 Ohm cable. In both the drawings is diagrammatically shown with F th electromagnetic near field which, expanding all around sai transmitting antenna At, encloses said receiving antenna Ar whic is connected to the said revelation unit R where 1 and 2 are,fo example, two germanium diodes used to demodulate the amplitud variation of the electromagnetic signal captured by the antenn Ar. To said revelation unit R is connected, through the resistor and the capaciotor 4,to said amplifier A; the function of th resistor atnd capacitor is to cut continuous component of the radi frequency signal in order to transfer, to the said amplifier A, o better, to the first operational amplifier 5,only the alternat component of the signal caused by the variation of the sai electromagnetic field F. In this manner it is possible to obtain self-adjusting condition of the circuit in order that slo variations of some parameters (external temperature, power suppl voltage, lenght and coupling characteristic of antennas) are no affecting the reliability of the electronic circuit. Furthermore said amplifier A includes, beside fe resistors and capacitors, the resistor 6 which applies the revealed signa to the second operational amplifier 7 for a further amplification. SUBSTITUTE Said amplifier A is connected to the acoustic module S whic include the transistor 8 which provides the output to the acousti transdoucer 9 for the audible alarm signal. Said transmitting antenna At is connected to the sai radio frequency oscillator T which, in this example, mainl comprises one transistor 10 and one coil 11 in orther to generat radio frequency oscillations coupled to the second coil 12, bu my alternatively be any kind of radio frequency free-oscillator. The electronic unit now described is encapsulated in small size module which can be easily arranged, for example, inside the vehicle close the reverse gear lamp from which ca receive the power supply of 12 Vdc during the parking operatio (see Fig. 3) . To said module will be connectedt«the two antennas At an Ar which will be easily arranged, for example, inside the plasti bumper. To this purpose it could be used a two wires electri cable where the distance between the two wires be possibly no less than 4-5 millimeters. According to the present invention, this preferre embodiment of the system installed on a vehicle ensures, when th circuit is switched on, the generation of a near electromagneti field F all around the transmitting antenna At. Due to th proximity of the conductive material of the vehicle and to th particular arrangement of the antenna At, the space configuration of this electromagnetic near field appears as diagrammaticall shown in Fig. 4,5,6. The receiving antenna Ar that, in thi case, is immerged in said electromagnetic field will receive thi radio frequency signal of constant amplitude. When any object, with the only exclusion of substances with very low electrica .conductivity (glass,ceramic,plastic with clean surfaces), wil enter this electromagnetic field, will generate a field parameter perturbation and consequentely will cause a reduction of the oscillations amplitude which, in this particular case,will b detected by the receiving antenna Ar and applied to th revealation module R and transformed, through the said amplifie A, in an audible alarm signal produced by the said acoustic modul S. It is to be appreciated that the foregoing description i of a preferred embodimentof of the invention which can be modifie in various ways without departing from the spirit and scope of th invention which could widely be changed in his circuita characteristics and in his aspplications field. For example, the system object of the present inventio could be utilized as a body detector for use in walking-throug access controls devices, as a proximity sensor for use i close/open doors, to actuate illumination or alarm systems an furthermore, with the use of antenna cables of appropriate lenght for perimetral protection systems. Furthermore, with appropriate improvements of the basila electronic circuit, it could be used as a warning device fo predetemined approaching distances in vehicular or object movement.

Claims: * C L A I M S * 1. - An electromagnetic detection system for parking operatio mainly for detecting obstacles during vehicles parking operation characterized in that is comprising: a transmitting-receiving mean of radiofrequency field; a mean capable of creating, all around said transmitting-receivin mean, an electromagnetic radiofrequency field; a mean capable of detecting the variations of said electromagnetic field (near field) produced by an object approaching the sai transmitting-receiving mean; a mean capable of segnalaizing such variations with an acoustic or wiev alarm signal indicating the presence and the approaching of an object. 2. - An electromagnetic detection system as claimed in claim 1, characterized in that the said transmitting-receiving mean is composed by one or preferably two wires or strips of electrical conductive material, used as antennas, coupled toghether an applied inside the body, which has to be protected, for all his lenght. 3. - An electromagnetic detection system as claimed in claim 1 or 2, chracterized in that the said mean capable to create a electromagnetic radio frequency field is composed by an electronic oscillator coupled to the said transmitting antenna. 4.- An electromagnetic detection system as claimed in claims 1 or 3, characterized in that the said electronic oscillator comprises one only transistor which, connected to a first coil, generates radio frequency oscillation which is inductively transferred to second coil connected to the said transmitting antenna. 5.- An electromagnetic detection system as claimed in claim 1, characterized in that the said mean capable of demodulating the variation of said electromagnetic field comprises a revealation unit coupled to the said receiving antenna immerged in said electromagnetic field. 6. - An electromagnetic detection system as claimed in claim 1 or 5 characterized in that the said revealation unit, capable of detecting the variations of the electromagnetic field, comprises two revealation diodes which demodulate the amplitude of the signal received by the said receiving antenna. 7. - An electromagnetic detection system as claimed in claim 1 characterized in that the said acoustic module comprises an acoustic transdouce . 8.- An electromagnetic detection system as claimed in any of claims 1-7 characterized in that the signal decoded by the acoustic transdoucer, for transforming into an alarm sound, ha been previously amplified by an electronic amplifier comprising first and a second operational amplifier. 9. - An electromagnetic detection system as claimed in any of claims 1-8, characterized in that a resistor and a capacitor connected between the said revealation unit and said amplifier give a self-adjustement of the electronic circuit in orther t avoid instability or malfunctioning of the system due t changement in external temperature, voltage supply and antenna characteristics as theyr lenght and installing configuration. 10.- An electromagnetic detection system as claimed in any o claims 1-9, characterized in that all the electronic component are encapsulated in a small size module which can be arrange close the reverse gear lamp of the vehicles and electricall connected to this lamp for power supply. SUBSTITUTE SHEET

Inventors: DEL SIGNORE MAURO, DEL SIGNORE, MAURO
Applicants: SIGNORE MAURO DEL, DEL SIGNORE, MAURO
Application year: 1993
Main classification: G01S13
IPC codes: B60Q1, B60W30, G01S13, G08G1