WO2009130725A1

WO2009130725A1 - Apparatus for detecting obstacles, in particular for assistance in driving and/or parking a vehicle

Info

Publication number: WO2009130725A1
Application number: PCT/IT2008/000286
Authority: WO
Inventors: Carlo Vedani
Original assignee: Cobra Automotive Technologies S.P.A.
Priority date: 2008-04-23
Filing date: 2008-04-23
Publication date: 2009-10-29

Abstract

An apparatus for detecting obstacles, in particular for assistance in driving and/or parking a vehicle, comprising: a plurality of detecting units (10), adapted to detect obstacles; a control unit (20) for receiving at least signals representative of detections from the detecting units (10) and generating notification signals (100); a first terminal (30) for generating a first voltage (VL); a second terminal (40) for generating a second voltage (VH), higher than the first voltage (VL); a conductive path (50) connecting the detecting units (50) to each other in succession and connecting this succession to the first terminal (30), the second terminal (40) and the control unit (20). Communication between the control unit (20) and detecting units (10) is obtained by overlapping of the first voltage (VL) by the second voltage (VH) in a controlled manner in the conductive path (50).

Description

APPARATUS FOR DETECTING OBSTACLES, IN PARTICULAR • FOR ASSISTANCE IN DRIVING AND/OR PARKING A VEHICLE

D e s c r i p t i o n.

The present invention relates to ^■ an apparatus for detecting obstacles, in particular for assistance in driving and/or parking a car.

Jt is known that some ^' vehicles, such .as cars, can be provided with sensors, positioned on the bumpers or close thereto, to detect the presence of obstacles and offer suitable signals to the driver, so that the latter is able to avoid undesirable collisions between the vehicle and said obstacles .

In more detail, said sensors are used during the^' parking steps, i.e. in the possible difficult situations of a vehicle when it is in close proximity to other vehicles or obstacles and it is necessary to position the vehicle itself in a precise manner.

The sensors present on a vehicle are generally governed by a control unit designed to communicate with each sensor so as to receive the^' results of the related detection from each said sensor and cause, if necessary, a signal for the driver.

Presently available are configurations in which the control unit is directly connected to several sensors, by .use of two or three pins and two or three dedicated wires or cables for connection with each sensor.

An alternative solution made available by the known art contemplates use of a bus for connection between the control box and sensors. In particular, in the configuration in which the sensors are connected in cascade, each sensor must have at least six terminals (positive input, negative input, positive output, negative output, bus input, bus output) at its disposal for a connection of this type.

It is apparent that both solutions briefly mentioned above have important operating disadvantages, above all in terms of high number of physical connections used

(cables/wires and/or pins) negatively affecting the production costs and making the whole system more complex.

Accordingly, the present invention aims ^• at providing an apparatus for detecting obstacles, in particular for assistance in driving and/or parking a vehicle, enabling a connection between the control unit and the different sensors to be obtained through use of a reduced number of cables/wires.

It is a further aim of the invention to make available an apparatus enabling a reduction to be obtained in the number of pins necessary on the control unit and/or the sensors for achieving a communication in any case complete and reliable.

An auxiliary aim of the invention is to provide an apparatus in which the sensors can be uniquely identified by the control unit and preferably also by other sensors .

A further auxiliary aim of the invention is to make available an apparatus in which the sensors are suitably powered in such a manner that communication between the sensors and the control unit can take place without downward limitations in the baud rate.'

The foregoing and further aims - are substantially achieved by. an apparatus for detecting obstacles, in particular for assistance in driving and/or parking a vehicle, in accordance with the features recited in the appended claims .

Further features and advantages ^' will become more apparent from the detailed description of a preferred and non- limiting embodiment of an apparatus in accordance with the invention. This description is taken with reference to the accompanying drawings , given by way of non- limiting example, in which:

- Figs. Ia, Ib, and Ic show possible embodiments of an apparatus in accordance with the invention;

- Fig. 2 shows a detecting unit being part of the apparatus seen in Figs_.. Ia, Ib, Ic,- - Fig. 3 -is a detail of an alternative embodiment of the apparatus in Figs. Ia, Ib, Ic.

With reference to the drawings, an apparatus for detecting obstacles, in particular for assistance to driving and/or parking of a vehicle in accordance with the invention has been generally identified by ■reference numeral -1.

Apparatus 1 applies to situations in which a moving body, such as a vehicle, must avoid collision with one or more elements foreign thereto, herein generally identified as "obstacles"..

These situations can occur in particular during the parking steps, when the driver, due to his/her inability or to an objective limitedness of the available spaces, needs to know the distance of his/her vehicle from a possible obstacle.

Apparatus 1 first of all comprises a plurality of detecting units 10, each adapted to detect the presence of obstacles .

In particular, each detecting unit is preferably provided with a sensor 16, adapted to generate radiation and to receive . corresponding reflected radiation so that the presence/closeness of obstacles can be determined .

Preferably, sensor 16 can be able to determine the distance to which an obstacle is, relative to the vehicle on which apparatus 1 is mounted.

As diagrammatically shown in Fig. 2, sensor 16 can comprise an ultrasonic transducer 16a,- coupled to a transformer 16b interlocked with a pair of transistors 16c preferably operated in a push-pull modality.

Also provided is a device 16d for reading the detection carried out by sensor 16.

Each detecting unit 10 is further provided with _^ a control block 14 for managing operation of the detecting unit 10; this control block 14 will be described in more detail in the following.

The detecting units 10 are preferably mounted on a bumper (or both bumpers) of a vehicle; more generally the detecting units 10 are mounted on the vehicle in such a manner that they can detect the presence of obstacles in the region in front of and/or in the region at the back of the vehicle itself.

By way of example, four-six detecting units can be mounted on the front bumper (or close thereto) and four detecting units on the rear bumper (or close thereto) .

Apparatus 1 also comprises a control' unit 20, associated with said detecting units 10 for receiving at least signals representative of detections from the detecting . units themselves 10 and generating corresponding notification signals 100.

The control unit 20 practically manages and co- ordinates operation of the detecting units 10; in particular it communicates with the detecting units 10 and generates suitable notification signals 100 as a function of the different detections.

It is to be noted that the notification signals 100 generated by the control ■ unit 20 can be intended both for the driver, through a suitable signalling interface provided in the vehicle, and for the control system of the vehicle itself, so that, if necessary, operations (e.g. emergency braking, speed limitations, etc.)^' can be performed in an automatic manner and without a relevant input by the driver.

Apparatus 1 further comprises a first terminal^' 30 for generating a first voltage VL, and a second terminal 40 for generating a second voltage VH.

The second voltage VH is higher than the first voltage VL. By way of example, the first voltage VL can be of 6 V, while the second voltage VH can be of 9 V. Apparatus 1 further comprises a conductive path 50 connecting the detecting units 10 in succession to each other and connecting the succession of detecting units 10 to the first terminal 30, -the second terminal 40 and the control unit 20.

The conductive path can be obtained for example through a wire, a cable possibly divided into several portions suitably interposed between the detecting units so as -to form the above described connecting structure.

For instance, data starting from the first detecting unit (as better clarified in the following, the closest to the second terminal 40) pass through all the other detecting, units before reaching the control unit 20, while data starting from the control unit .20 and having to reach the first detecting unit do not pass through other detecting units.

Likewise, data starting from the last detecting unit

(as better clarified in the following, the closest to the first terminal 30) reach the control unit without passing through other detecting units, while data starting from the control unit 20 and having to reach the last detecting unit pass through all the other detecting units.

In this way, communication between the control unit 20 and detecting units 20 can be obtained through overlapping of the second voltage VH on the first voltage VL in a controlled manner in the conductive path 50.

Practically, the first voltage VL is used to power the detecting units 10 when the second voltage VH is missing; in fact usually it is the second voltage VH that is used for carrying out feeding during the detecting step in which sensors 16, to, be better described in the following, are employed.

When some information is to be exchanged between the control unit 20 and one or more of the detecting units 10, the second voltage VH (that, as said, .is higher than the first one) is turned off in a controlled and regulated manner, so ^' as to transmit the desired information.

Therefore, the detecting units 10 are always powered/ exactly due to the first voltage VL; in this way, loss of the information stored inside the detecting units 10 themselves is avoided and there is no dependence on the frequency of the pulses passing along the wire.

In more detail, apparatus 1 preferably comprises^' a main switch 60, interposed between the second terminal 40 and the succession of detecting units 10, and interlocked with the control unit 20 for controlled overlapping of the first voltage VL by the second voltage VH and sending of information to one or more detecting units 10.

In this way, controlled overlapping of the second voltage VH on the first voltage VL generates a sequence of ^' pulses having a duration and/or frequency arid/or phase and/or time distance through which coding of the information exchanged between the control unit 20 and detecting units 10 occurs.

In other words, when the control unit 20 must send a piece of information to one or more detecting units 10 (this information can be a command for detection activation, a request for the detection results, etc.) , it causes opening and closing of said main switch 60 in a predetermined sequence, so as to generate a series of pulses representing the piece of information . that has to be transmitted.

The control unit 20 is in particular provided with a transmitting terminal 21, through ^'which it acts on said main switch 60.

As for the detecting units 10, they are designed for interpretation of these pulse sequences and therefore can act consequently.

Preferably, each detecting unit 10 comprises a first interface 11 to be connected to the first terminal 30, and a second interface 12, to be connected to the second terminal 40.

As mentioned above, each detecting unit 10 preferably

^• comprises a control block 14; the .function of the latter is to selectively adjust a connection between the first and second interfaces 11, 12 and cause overlapping of the first voltage VL by the second voltage VH in the conductive path 50 sending information at least to said control unit 20.

In other words, when the detecting unit 20 must send information to the control unit 20 (this information preferably comprising results of detections carried out by the detecting unit itself) , the control block 14 of this detecting unit 10 carries out opening and closure of the connection between ^'the first and second - interfaces 11, 12 so as to generate a code representative of the information to be transmitted.

To this aim, each detecting unit 10 preferably comprises an auxiliary switch 15, interposed between the first and second interfaces 11, 12 and interlocked with the control block 14.

As diagrammatically shown in Fig. 2, the auxiliary switch 15 can consist of a MOSFET 15a.

The control unit 20, through reception of a succession of high values (corresponding to the second voltage VH) and low values (corresponding to the first voltage VL) will be able to interpret the information.

Preferably, each detecting unit 10 is further provided with a third interface 13 for receiving the first voltage VL and/or the second voltage VH.

Practically, during operation, through the third interface 13 the detecting unit 10 normally receives the second voltage VH that is used as power supply,- when codes are transmitted through the conductive path 50, the detecting unit 10 can "hear" them and, if- suitable, can interpret them and perform possible commands received or other actions determined as a function of what received.

As above mentioned, the conductive path 50 connects the different detecting units 10 in- succession; in addition, preferably, the conductive path 50 has a first end 51 to be connected to the second terminal 40 and a second end 52.

The second end 52 is connected, through a first branch 53, to the first terminal 30 and, through a second branch 54, to the control unit 20; in particular, the second branch 54 is connected to a receiving terminal 22 of the control unit 20. In fact, through the second branch 54,. the control unit 20 receives data and information from the detecting units 10 though the conductive path 50.

Preferably, as shown in Figs. Ia-Ic, the first branch 53 comprises^' a diode 53a, such oriented that the second voltage VH cannot reach the first terminal 30.

Fig. 3 shows a detail of apparatus 1, wherein a slightly different modality is employed for generation of the first voltage VL; from the second terminal 40 an auxiliary branch 31 starts which comprises a Zener diode oriented as shown in the figure and having a predetermined reverse voltage, of 3 V for example. In this way, a first voltage VL lower than the second voltage VH will be available at the first terminal 30

(in the exemplary case in which the second voltage VH is 9V, the first voltage VL can be 6 V) .

Advantageously each detecting unit ,10 is uniquely associated with an identification code to be encoded through controlled overlapping of the second voltage VH on the first voltage VL; in this manner, each detecting unit 10 , can • be reached and identified along the conductive path 50 through generation of a suitable pulse sequence.

Each detecting unit 10 is provided with a memory .in which at least its identification code is stored, so that the detecting unit 10 itself can recognise the information sent and directed to it. The possibility of uniquely identifying each detecting unit 10 is particularly useful because the different sensors, depending on the position they have on the

^• bumper, must be coded with different range and different s.hape; it is also important for diagnostic purposes, in order to be able to clearly identify the sensor having a malfunction.

Preferably, the succession of detecting units 10 is arranged from the first end 51 of the conductive path 50 to the second end 52 of the conductive path 50, and the signals used for communication between the detecting units 10 and control unit 20 propagate from the first to the second ends 51. 52.

Figs. Ia, Ib, Ic show different embodiments of apparatus 1, relating to different solutions -for earthing of the different detecting units.

In Fig. Ia, the (four-pin) detecting units 10 are all sequentially connected with each other, and the first detecting unit is earthed.

In Fig. Ib, all (three-pin) detecting units are individually connected to a single earth terminal.

In Fig. Ic, each (three-pin) detecting unit 10 is connected- to a respective terminal of the control device 2 comprising the control unit 20 and the main switch 60; each of said terminals is connected to a single earth.

From the point of view of operation, the following steps are carried out. Initially, before apparatus 1 can operate, the different detecting units 10 are not yet recognisable

(i.e. uniquely identifiable) and all auxiliary switches

15 are open; therefore only the detecting unit that is

5. immediately, downstream of the main switch 60 is fed with the second voltage VH, since said main switch is in the closed condition. •

The control unit 20 therefore generates a first data0 packet (or "telegram") so as to define identification of the first detecting unit 10 that is immediately downstream of the main switch 60.

When the first detecting unit 10 has received its5 identification and has stored its identification code, it closes its auxiliary switch 15 , and the control unit 20 generates a second packet of identification data, intended for the second detecting unit that, due to closure of the auxiliary switch 15 of the first0 detecting unit, is fed ^'with the second voltage VH.

Going on in this manner, a condition is reached at which all detecting units 10 have been identified and have closed their auxiliary switch 15. 5 .

The control unit 20 recognises this situation because it receives the second voltage VH on its receiving terminal 22; vice versa, as far as there was still at least one detecting unit 10 to be identified, at least 0 one auxiliary switch 15 was open and the second voltage VH could not be received by the receiving terminal 22 of the control unit 20.

When the initialisation step is over, all au-xiliary switches 15 are closed and the main switch 60 is normally closed; under this situation, the detecting units 10 are all powered and there is no information transmission.

Subsequently, the control unit 20 sends an activation command so that the detecting units 10 (not necessarily all of them, but also some of them, depending on the command sent) start verifying the presence of possible obstacles; the activation command is sent by opening and closing the main switch 60 following a predetermined sequence .

In particular, the activation command can make one or more detecting units emit radiation, and make one or more detecting unit detect the corresponding reflected radiation; therefore, following an activation command generated by the control unit 20, each detecting unit 10 can be called to only emit radiation, to only detect a reflected radiation, or to perform both operations.

Then, when the control unit 20 has to receive the results of the different detections, it' generates a request signal, dialling a further code via the main switch 60.

After generation of this second code, the main switch 60 is maintained to the closed condition.

Then a step starts in which the detecting units 10 that have been concerned with the command, in succession, send their data to the control unit 20, through a suitable sequence ^' of opening/closing operations of their auxiliary switches 15.

Depending on the code sent by the control unit 20, the detecting units 10 know which of them must answer and which sequence is to be followed; preferably, the more the detecting unit is close to the main switch 60, the higher the answer priority is,- if the detecting units 10 leave their auxiliary switch 15 closed, a "high" pulse will be transmitted, while if they open their auxiliary switch 15, a "low" pulse will be transmitted

(it is to be noted that, in the absence of other signals, the receiving terminal 22 of the control unit 20 is connected to the first terminal 30 and therefore receives the first voltage VL) .

All detecting units disposed downstream, by maintaining their auxiliary switch 15 closed, allow data coming from the detecting units upstream to reach the receiving terminal 22 of the control unit 20.

Simultaneously, the other detecting units 10 are also able to "listen to" data sent from the detecting unit upstream to the control unit 20, since they are passed through by such an information flow.

Then, the subsequent detecting unit that has to answer is able to determine when the preceding detecting unit has finished its transmission and can subsequently start transmission of the following packet of detection data.

It will be understood that each of the detecting units that has to give an answer knows how many detecting units before it have to answer, and knows the duration of each answer; in fact the answer is formed of a substantially fixed number of bits .

Therefore, each detecting unit is able to determine the moment at which it has to give its answer (if requested) .

It is to be noted that the first detecting unit, at the end of its transmission, keeps its auxiliary switch 15 in the closed condition, so as to enable also the detecting units downstream to use the second voltage VH.

Data transmission from the detecting units 10 to the control unit 20 goes on as described above, until the last detecting unit (i.e. the one concerned with the command and the closest to the first terminal) is reached, which last unit will transmit the detected data to the control unit 20.

The control unit, depending on the received data, will, if necessary, send a suitable notification signal 100 to the vehicle's driver and/or the vehicle's automatic control system.

When the data- transmitting step from the detecting units 10 to the control unit 20 has been completed, a new detection step can begin, being activated as above described by a related activation command preferably different from the preceding one, sent by the control unit 20 to all detecting units 10 through a controlled sequence of opening/closing actions of the main switch^' 60. "

The invention achieves important advantages .

First of all, due to the above described structure the number of wires and/or pins used for obtaining a connection between the control unit and the different detecting units is reduced.

In addition, the different detecting units can be uniquely identified, so as to make coding and diagnostics of the different units quick and efficient.

Another advantage is found in that the detecting units are suitably powered, so that communication between the detecting units themselves and the control unit is not affected by the baud rate used.

Claims

■ C L A I M S

1. An apparatus for detecting obstacles, in particular for assistance in driving and/or parking a vehicle, comprising: _t

- a plurality of detecting units (10) , adapted to detect obstacles;

- a control unit (20) associated, with said detecting units (10) for receiving at least signals representative of detections from said detecting units •(10) and generating notification signals (100) ;

- a first terminal (30) for generating a first voltage (VL) ; a second terminal (40) for generating a second voltage (VH) , higher than said first voltage (VL)-;

- a conductive path (50) connecting the detecting units (10) to each other in succession and connecting said succession to said first terminal (30) , second terminal (40) and control unit (20) , communication between said control unit (20) and detecting units (10) being obtained by overlapping of said first voltage (VL) by said second voltage (VH) in a controlled manner in the conductive path (50) .

2. An apparatus as claimed in claim 1, further comprising a main switch (60) interposed between said second terminal (40) and said succession of detecting units (10) and interlocked with said control unit (20) for controlled overlapping of said first voltage (VL) by said second voltage (VH) and sending of information to one or more detecting units (10) .

3. An apparatus as claimed in claim 1 or 2 , wherein each of said detecting units (10) comprises: - a first interface (11) to be connected to said first terminal ( 30 ) ;

- a second interface (12) to be connected to said second terminal (40) ;

- a control block (14) for selectively adjusting a connection _ between said first and second interfaces

(11, 12) and carrying out overlapping of said first voltage (VL) by said second voltage (VH) in said conductive path (50) and sending information at least to said control unit (20) . '

4. An apparatus as claimed in anyone of the preceding claims, wherein each detecting unit (10) comprises a third interface (13) for receiving said first voltage (VL) and/or said second voltage (VH) .

5. An apparatus as claimed in anyone of the preceding claims, wherein said conductive path (50) has a first end (51) to be connected to said second terminal (40) and a second end (52) connected to said first terminal (30) through a first branch (53) and to said control unit (20) through a second branch (54) .

6. An apparatus as claimed in anyone of the preceding claims, wherein said controlled overlapping of the first voltage (VL) by the second voltage (VH) generates a sequence of pulses having a duration and/or frequency and/or phase and/or time distance incorporating information exchanged between said control unit (20) and detecting units (10) .

7. An apparatus as claimed in anyone of the preceding claims wherein each detecting unit (10) is uniquely associated with an identification code to be encoded through controlled overlapping of said first voltage (VL) by said second voltage (VH) .

8. An apparatus as claimed in anyone of the preceding claims, wherein said succession of detecting units (10) is arranged from the first end -(51) of said conductive path (50) to the second end (52) of said conductive path (50) , .signals used for communication between said detecting units (10) and control unit (20) propagating from said ■ first to said second ends (51, 52) .

9. An apparatus as claimed in anyone of the preceding claims, wherein said first voltage (VL) is a supply voltage sufficient for said detecting units (10) .

10. An apparatus as claimed in claims 2 and 5, wherein said control unit (20) has a transmitting terminal (21) connected to the main switch (60) , and a receiving terminal (22) connected to the second branch (54) of said conductive path (50) .