FR3031596A1 - ULTRASONIC MEASUREMENT SYSTEM AND METHOD FOR MANAGING THE SAME - Google Patents

Abstract

A method of managing an ultrasound transceiver facility (20) comprising: - transmitting a first signal representing a first code mode by a first ultrasonic sensor (1) of a first group (G 12) in a first measurement cycle, - transmitting a second signal using a second ultrasonic sensor (2) of the first group (G 12), - receiving the echo of the first signal and the second signal by a third sensor to ultrasound (1, 2), and - distinguish between the part of the echo from the first signal and that of the second signal by decoding the codeword.

Description

FIELD OF THE INVENTION The present invention relates to a method for managing an ultrasound transmission-reception installation as well as to an ultrasound system and to a means of transport equipped with such a system and implementing this process. STATE OF THE ART For many years, ultrasonic emission-reception facilities (abbreviated ultrasonic sensors) have been used in the automotive industry for environmental detection and distance measurement. The driving assistance functions also frequently rely on ultrasonic sensors typically used in groups of four to six sensors per bumper of a means of transport (hereinafter referred to as "vehicle" for the purpose of simplification).

DE 10 2008 007 667 A1 describes a method for managing a parking or storage maneuvering assistance system using ultrasonic distance sensors operating in two different modes with different transmission sequences over time. . In particular, this document proposes to switch according to the speed of the vehicle. The document EP 1 105 749 B1 describes an object gripping device by ultrasonic receiver-emitters which modifies the transmission signals with a variable characteristic in time and in particular according to a random function. To avoid that the waiting time announced for the exploitation of received echoes results in a simultaneous neutralization of several systems and then by a superposition, it is further proposed that after the detection of a superposition of systems, we have a random waiting time. The choice of a new carrier frequency to avoid disturbing two systems must be done randomly to prevent the two systems from interfering with each other, even after the carrier has been modified. DE 10 2011 109 830 A1 describes a method for determining the origin of a reception signal received by an ultrasonic sensor of a vehicle and which examines different transmission signals encoded after reception of the reflected signal and extraction. code word.

Subsequently, the extracted code word is compared with the coding of the codeword used for the transmission signal, thus avoiding having to make a correlation. Current ultrasound systems typically operate with a fixed frequency in the range of 40 kHz-50 kHz for transmit mode and receive mode. The identical working frequency used by all sensors ensures cross-echo mode, ie a sensor can receive the echo frequency of the neighboring transmitter sensor. To use cross-echo information correctly in a parking aid system, it is necessary to have a perfect association with the sensor-transmitter. A multiple emission by sensors with an unambiguous association of the echo to a sensor is only possible if this is ensured by the geometry of the mounting positions of the sensors, for example in the front position / rear position or the intermediate sensors by compared to sensors installed laterally. In current systems, this limits the rate of measurement update of the systems (measurement cycles per unit of time) because typically four forward sensors or four rear sensors have "visibility ranges" or input ranges that overlap and so they are not suitable for transmitting in the same measurement cycle. In addition, the use of fixed working frequencies limits the robustness of detection which will have little security vis-à-vis disturbance by ultrasonic signals from other vehicles.

Object of the invention The object of the present invention is to improve the recognition of the signal and the preparation of the signal by coding to remedy or at least mitigate the disadvantages mentioned above. DISCLOSURE AND ADVANTAGES OF THE INVENTION For this purpose, the subject of the invention is a method of managing an ultrasound transmission-reception installation consisting in transmitting a first signal representing a first code mode by a first sensor to ultrasound of a first group of ultrasonic sensors in a first measurement cycle, emitting a second signal using a second ultrasonic sensor of the first group, receiving the echo of the first signal and the first signal. second signal by a third ultrasonic sensor and distinguishing between the echo portion from the first signal and the portion from the second signal by decoding the code word. In other words, the problem defined above is solved by the invention by a method of managing an ultrasound transceiver. This installation can in particular apply to a vehicle (motor vehicle). The installation comprises, as indicated above, several ultrasonic sensors arranged so that at least their input ranges (possibility of receiving an echo signal from a neighboring sensor) overlap partially. In a first step, a first signal representing a first code word is transmitted by means of a first ultrasonic sensor of a first group of ultrasonic sensors emitted in a first measuring cycle. The first measurement cycle is the period during which an ultrasound signal is emitted with the ultrasound transceiver and the first echo of the signal coming from the environment of the installation is received. emission-reception. According to the invention, the first signal is modeled to be able to recognize its properties as a function of time and reconstruct it.

In other words, the first signal has a kind of fingerprint that allows a unambiguous association between the echo and the original ultrasonic sensor. Then, a second ultrasonic sensor of the first group or the other group emits a second signal to the environment. The second signal may also have a codeword, but which differs from that of the first signal. Then, the echoes of the first signal and the second signal are received by means of a third ultrasonic sensor; the third ultrasonic sensor is for example the first and / or the second ultrasonic sensor. Alternatively, the first and second ultrasound sensors 30 may be considered for the reception phase as corresponding to a third ultrasonic sensor. Alternatively, the ultrasonic sensor may be an additional ultrasonic sensor with respect to the first and second ultrasonic sensors. Optionally, at least the echo of the first signal and / or the echo of the second signal are further received by a fourth ultrasonic sensor. Next, the two components of the second signal from the first signal are distinguished by decoding the code word. This is done for example by appropriate filtering. For this purpose, the timing diagram of the filter is adapted to that of the predictable signal and the components of the echo signal of the filter output signal which are very different from the first signal are neutralized. Then, each signal part contained in the echo received is associated with a corresponding transmission operation, for example an ultrasonic sensor as the original sensor, and the environment is analyzed, for example on the basis of the travel time. the signal, the intensity of the echo, etc. according to the state of the art. In this way, per unit time, it will be possible to emit more ultrasound signals and to receive echoes, which considerably increases the resolution in space and time for the ultrasonic emission-reception installation according to the invention. invention with respect to the state of the art. Environmental information will be more accurate and reliable. Preferably, the ultrasonic sensors of the first group are arranged relative to each other to receive the respective crossed echoes. This applies in particular to all ultrasonic sensors in a group. In other words, one member of the group may receive at least one echo from another member of the group, preferably from all members of the group as far as the reflective object allows. The second signal represents a second code word. In order to have good recognition security for distinguishing the components from the first signal with respect to the echo components from the second signal, the signs of the first code word of a signal segment whose properties are distinguished are distinguished. differ in time by appropriate filtering. This excludes that code word signs whose echoes potentially arrive on the same ultrasonic sensor, may combine and prohibit a single association with an original ultrasound sensor. An example of such code words are orthogonal codes. For example, two separate signals from each other can also be used for the first and second codewords. This greatly increases the recognition and the association of the received echo and gives better immunity to the disturbances of the ultrasonic sensors. In particular, it is possible to guarantee that successive segments of time signals differ in their fundamental frequency and / or in the evolution of their fundamental frequency, especially with respect to the initial frequency and / or the target or target frequency and / or the frequency variation direction and / or the frequency variation rate and / or the frequency range (For example, a range characterized by a low frequency h (m) and a high limit frequency or a start frequency and a target frequency) so that appropriate filtering after echo reception can be identified. Because of the simple properties of a signal or a predefined combination of signal properties, different characteristics or code words for the signals of the ultrasonic transceiver according to the invention can be used and distinguished from one another. by appropriate filtering (digital and / or analog). The second signal can be distinguished for example by a considerably shorter duration and / or a considerably greater amplitude than those of the first signal. In particular, a shorter duration means that for near-range detection, faster results will be obtained for unambiguous identification of corresponding echo signals and considerably lower the detection limit of the near area. Consequently, deviations between objects that are very close to the environment may be reported earlier and, if necessary, corresponding warning signals will be emitted earlier. In the case also of objects moving towards the ultrasonic sensor system, a much earlier warning signal can be emitted. It is thus possible to stop the operation of the echo from the second signal while that of the first signal continues. This occurs if both the first and second signals are reflected by the same object in the environment. In particular, it is advantageous to emit a strongly shortened signal if the same ultrasonic sensor is used for echo reception, and thus the oscillation amplitude of its membrane must fall below one. predefined limit, before the echo can be reliably detected with respect to the signal that ends. To avoid specific code disturbances over a prolonged period, a method called "code switching" is used in the context of the present invention. Thus, in a second measuring cycle which extends in particular the first measuring cycle directly, a third signal is transmitted representing a third code word using the first ultrasound sensor of the first group of ultrasound sensors. In a previous measurement cycle, this first ultrasonic sensor had issued the first codeword as described above. Since the first code word and the third code word are in different frequency ranges, in particular disjoint frequency ranges, a disturbance of narrow bands (for example by a foreign ultrasound signal) can not disturb than one of the two code words, which no longer allows a reliable detection of its echo. If the disturbance lasts, at least one of the transmitted code words also leads to an echo that will be recognized safely and used for the detection of the environment.

In addition, the method according to the invention can emit a fourth signal representing the first code word using a fourth ultrasonic sensor belonging to a second group. The ultrasonic sensors of the first group may be arranged with respect to those of the second group so that they can not receive echoes of ultrasound signals from the second group. In other words, the first code word is transmitted during the first measurement cycle only by the first ultrasonic sensor and by the fourth ultrasonic sensor, which limits the number of code words and makes it possible to increase their number. distance as signs. This increases security and recognition. As for geometric considerations, there can be no overlap between the first group and the second group, the recognition security is not reduced by the simultaneous use of the first code word. Preferably, the speed of circulation of the ultrasonic transmission-reception system (which is equipped with a motor vehicle, for example) is compared with a predefined reference and, in response to the results, the code word to be transmitted. by the first ultrasonic sensor in the next measurement cycle will be selected from a predefined number of codewords. For example, the length of the code word can be adapted so that at a vehicle speed above a predefined reference, the pre-warning time is maintained until a collision using a password. shorter code or more short codewords. As described, a long code word for a high velocity might require long detection as the object of the environment and the moment of collision approach in the meantime in a dangerous manner. . In this way, the update rate and the detection range are improved at the cost of less disruption neutralization.

According to the invention, it is assumed that the ultrasonic sensors used are able to transmit a coded transmission signal and simultaneously receive several foreign codewords from neighboring sensors and to be able to detect them. This is done for example with linear frequency ramps and the use of correlation methods by the receiving unit. We will have a reserve of additional detection robustness by a further fluctuation of the order of the code words used as well as by a further variation of the code and by the use of a stochastic waiting time between the different patterns of the code. emission (all the properties thus mentioned can be used separately or in any combination). This allows for example to neutralize foreign sources of ultrasound or own disturbances, triggered by annoying reflections. According to a second development, the subject of the invention is an ultrasonic measurement system having a first group of ultrasonic sensors with a first and a second ultrasonic sensor and a second group of ultrasonic sensors with a third ultrasonic sensor. ultrasound. The ultrasonic sensors of the first group are arranged geometrically with respect to those of the second group so as not to be able to receive the echoes of the signals of the second group. In other words, cross-echo reception is excluded under any technically interesting usage conditions (practically any condition). Furthermore, the ultrasonic measurement system allows the above-defined method to be performed and the resulting characteristics, combinations of features and advantages correspond to what has been described above for the process; this information is not included for purposes of simplification. According to a third development, the invention relates to a means of transport, in particular a vehicle, such as a passenger vehicle, a carrier, a truck or commercial vehicle, an aerial vehicle and / or a vehicle. aquatic device having an ultrasonic measurement system according to the second above development of the invention. The means of transport may utilize the ultrasonic measurement system to have application and / or operating information of any driver assistance system. Also, for the means of transport reference will be made to the features and combinations of features as well as the advantages developed above. In contrast to the state of the art, the invention does not only propose to disturb emissions and to have a stochastic waiting time for the transmission commands of different ultrasonic sensors. Moreover, by an appropriate choice of the code (code word) and a corresponding wiring of the ultrasonic sensors in the combination of the system, such as "transmitter", "receiver" or "transmitter and receiver", to realize the advantages described above. above the ultrasonic measurement system so as to cover both the near area and the remote area of the environment by allowing multiple transmissions with overlapping sensor detection ranges. Optionally, code switching increases detection security in the direction of deleting erroneous object detections.

The present invention will be described hereinafter in more detail with the aid of examples of methods for managing an ultrasound transceiver system shown in the accompanying drawings in which: FIG. 1 is a diagrammatic overall view of the ultrasonic measurement system according to the invention; FIG. 2 shows a first table showing a first mode of operation of an ultrasonic measurement system according to the invention; FIG. 3 shows a second table showing an alternative embodiment of an ultrasonic measurement system according to the invention; FIG. 4 shows a third table of a variant of operation of a measurement system by According to the invention, FIG. 5 shows a fourth table of an operating variant of an ultrasonic measurement system according to the invention; FIG. 6 shows a fifth table which shows a variant of operation. of an ultrasonic measuring system according to the invention 15 and - Figure 7 shows a flow chart explaining different steps of an embodiment of a method according to the invention. DESCRIPTION OF EMBODIMENTS FIG. 1 is a schematic top view of an exemplary embodiment of an ultrasonic measurement system 20 composed of ultrasonic sensors 1, 2, 3, 4, 5, 6 integrated in the bumper of a passenger vehicle 10 constituting an example of a means of transport. The ultrasonic sensors 1, 2, 3, 4, 5, 6 have respective lobes 11, 12, 13, 14, 15, 16. The ultrasonic sensors 1, 2, 3, 4, 5, 6 are connected by a signal transmission line to a central control unit 7 constituting an operating unit. Depending on the environment objects, the ultrasonic sensors 1, 2, 3, 4, 5, 6 are only able to receive cross echoes in a conditional manner. For example, the ultrasonic sensors 1, 2, 3, 4, 5, 6 are divided into groups G12, G23, G34, G35, G56 to develop the possibility or impossibility of cross-echo reception. For example, groups G12 and G45 are so far apart that they can not receive echoes from signals of group G45 for ultrasonic sensors 1, 2 of group G12. The tables of FIGS. 2 to 6 relate to the operating modes resulting from the arrangement of the ultrasonic sensors 1, 2, 3, 4, 5, 6 of FIG. 1. FIG. 2 shows a table explaining a transmission pattern. possible reception for ultrasonic sensors 1, 2, 3, 4, 5, 6 (first row of the table) corresponding to the arrangement given by way of example in FIG. 1. Under the first line, two other lines represent a first measurement cycle (reference 1) and a second measurement cycle (reference 2) represented by a second block. In the cells of the tables the writing conventions are as follows: 10 - "s" is the sensor which, in one measurement cycle at a time, also emits and receives a direct echo, - "r" indicates a sensor which, in a measurement cycle receives only crossed echoes and emits no signal, and - "s / r" indicates the sensor which also transmits and receives in direct / cross mode. The right part of the table represents for the six ultrasound sensors 1, 2, 3, 4, 5, 6 (the numbering in the first line of all the tables corresponds to Figure 1) and the measurement cycles 1 and 2 are each time represented as if the ultrasonic sensors 1, 2, 3, 4, 5, 6 were operating in the measurement cycle as a direct D receiver and / or as a cross-echo receiver C. The hatches represent four different code words emitted by the ultrasonic sensors 1, 2, 3, 4, 5, 6 or receiving them in the form of echo. With one exception, the codes used must ensure a good mutual neutralization: only the codes corresponding to the first sensor in the first measurement cycle and the sixth sensor in the second measurement cycle emitting in the example presented do not necessarily have of particular property to neutralize each other. FIG. 3 shows a possible modification of the operating mode represented in FIG. 2 by the introduction of particularly short signals characterized by the word "short" (writing convention). Unlike the legend relating to Figure 2, the word "short" is representative of the expression "short" indicating that the sensor concerned sends the short signal and allows to receive the direct echo as it follows the right half of the table (the signals "short" are received and used during the same measurement cycle and with the same ultrasonic sensors 1, 2, 3, 4, 5, 6. FIG. 4 shows a development of the operating mode. 3, which makes it possible to optimize the update rate of the measurements (the number of measurement operations per unit of time) For this, in each measurement cycle 1, 4, using two ultrasonic sensors 1, 2, 3, 4, 5, 6 spaced apart from each other, a short "short" signal is emitted and received, which may for example have a short pulse of frequency in particular, for the sixth ultrasonic sensor in the second cycle of my On the other hand, another transmission operation has been provided and for the first ultrasonic sensor in the fourth measuring cycle, another transmission operation (each with direct echo reception) has been implemented. For the operating mode shown in FIG. 4, a good reciprocal neutralization of the code transmitted for example in the third measurement cycle from the first and second ultrasonic sensors is required. In addition, a good reciprocal code neutralization with which the fifth and sixth ultrasonic sensors emit in the second measurement cycle is required.

FIG. 5 shows an example of such code switching to increase the robustness of the detection for a higher update rate. Instead of what is shown in FIG. 2, there are only two different code-cycle mode combinations to be implemented and in the third and fourth 25 measurement cycles, the first ultrasonic sensor 1 operates with the code which was provided in the first and second measurement items for the sixth ultrasonic sensor (and not the other way around). The same applies to the codes transmitted in the first and second measurement cycles by the second and third ultrasonic sensors or the fourth and fifth ultrasonic sensors. Specific code errors can be avoided in this way, at least for a period of four measurement cycles. FIG. 6 shows an example of code switching based on the transmission patterns of FIG. 3. In this case, the code transmitted by the first ultrasonic sensor 1 in the first measuring cycle 3031596 12 is replaced after four cycles. measurement by a code not used until then. The same applies to the code that is for example issued by the fifth ultrasonic sensor 5 in the first measurement cycle. In this way, at the latest after four measurement cycles, the code used is changed to avoid systematic errors of recognition over a long period and thus improve the detection of a collision. FIG. 7 shows the steps of an exemplary embodiment of the method of the invention for managing an ultrasound transmission-reception facility. In step 100 a first signal representing a first code word is transmitted by means of a first ultrasonic sensor belonging to a first group of ultrasonic sensors and using a fourth sensor. Ultrasound of a second group of ultrasonic sensors is emitted each time in a first measuring cycle. In step 200 a second signal is emitted using a second ultrasonic sensor of the first group. In step 300 the echoes of the first signal and the second signal are received by a third ultrasonic sensor identical to the first ultrasonic sensor. In step 400, the components of the echo from the first signal and those from the second signal are distinguished by decoding the code words contained in these parts. The decoding of the code words allows a higher measurement signal density per unit of time with always error-free detection and association. In step 50 a third signal is generated representing a third code word using the first ultrasonic sensor of the first group of ultrasonic sensors in a second measurement cycle. There is thus a code switch to avoid in principle code-specific recognition errors. In step 600, a flow rate of the ultrasonic transceiver system (e.g., a transport means equipped with the invention) is compared to a predefined reference. In response to the event, in step 700 a code word is selected that the first ultrasonic sensor must transmit in the next measurement cycle in time; this selection is made in a predefined set of codewords. Since the rate of circulation exceeds the predefined reference, a multiplicity of shorter codeword applications is produced, for example, to improve the system response time and thereby optimize the warning time. 5 10

Claims (5)

CLAIMS 1 °) A method of managing an ultrasound transceiver (20) comprising: transmitting (100) a first signal representing a first code mode by a first ultrasonic sensor (1) of a first group (G12) of ultrasonic sensors (1-6) in a first measurement cycle, transmitting (200) a second signal using a second ultrasonic sensor (2) of the first group (G12), receiving (300) ) the echo of the first signal and the second signal by a third ultrasonic sensor (1, 2), and distinguishing (400) between the echo portion from the first signal and the portion from the second signal by decoding the code word. Method according to Claim 1, characterized in that the ultrasonic sensors (1, 2) of the first group (G12) are arranged in the space to receive crossed echoes. 3) Method according to claim 1, characterized in that the second signal represents a second code word. Method according to claim 1, characterized in that the signs of the first code word consist of a time signal segment whose properties as a function of time are distinguished from those of the second signal by appropriate filtering. Method according to Claim 4, characterized in that the successive time signal segments are distinguished by the fundamental frequency and / or the evolution of the fundamental frequency, in particular according to the starting frequency and / or the frequency of the arrival and / or 3031596 the direction of variation of the frequency and / or a rate of frequency variation and / or a frequency range. 6. Process according to claim 1, characterized in that the second signal has a much shorter duration and / or an amplitude different from that of the first signal. The method according to claim 1, characterized in that the echo operation from the second signal is already completed at the instant when the first signal is still in operation. The method according to claim 1, characterized in that it further comprises the steps of: transmitting (500) a third signal representing a third code word using a first ultrasonic sensor ( 1) of the first group (G12) formed of ultrasonic sensors (1-6) in a second measurement cycle and / or transmitting (100) a fourth signal representing the first code word using a third sensor with ultrasound (4) of a second group (G45), the ultrasonic sensors (1, 2) of the first group (G12) being arranged in space to receive no signal echoes from the second group (G45) ). Method according to Claim 1, characterized in that the association between the used code words and the ultrasonic sensors (1-6) is modified for a next transmission cycle, the modification being carried out in particular. according to a predefined succession and / or stochastically. The method according to claim 1, further comprising comparing (600) a flow velocity of the ultrasound receiving facility (20) to a predefined reference and in response thereto. selects (700) a code word to be transmitted by the first ultrasonic sensor (1) in the next measurement cycle from a predefined set of code words, in particular of modified length. 11 °) Ultrasonic measuring system having: a first group (G12) of ultrasonic sensors (1, 2) having a first ultrasonic sensor (1) and a second ultrasonic sensor (2) and a second group (G45) ultrasonic sensors (4, 5) with a third ultrasonic sensor (4), the ultrasonic sensors (1, 2) of the first group (G12) being arranged in the space to not receive second group echoes (G45) and the ultrasonic measurement system (20) executing the method according to any of claims 1 to 10. 12) Means of transport equipped with an ultrasonic measurement system ( 20) according to claim 11 implementing a method according to any one of claims 1 to 10 consisting in: transmitting (100) a first signal representing a first coded mode by a first ultrasonic sensor (1) of a first group (G12) of 25 ultrasonic sensors (1-6) in a first measurement cycle, transmitting (200) a second signal to the aid e of a second ultrasonic sensor (2) of the first group (G12), receiving (300) the echo of the first signal and the second signal by a third ultrasonic sensor (1, 2) and distinguishing (400) between the echo portion from the first signal and the portion from the second signal by decoding the code word. 35