GB2540869A

GB2540869A - Variable communication window for a data transmission from a sensor to a control device

Info

Publication number: GB2540869A
Application number: GB1610847.4A
Authority: GB
Inventors: Rudolph Marcel; Schumann Michael
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2015-06-24
Filing date: 2016-06-21
Publication date: 2017-02-01
Anticipated expiration: 2036-06-21
Also published as: FR3038065A1; GB201610847D0; GB2540869B; FR3038065B1; DE102015211740A1

Abstract

The present invention relates to a method for a data transmission from an ultrasonic sensor (100) to an electronic control unit (150). Echo information is produced by the sensor in a measuring cycle Mn, Mn+1 etc. Each measuring cycle has a measuring window MFn, MFn+1 etc. Each echo information is transmitted from the sensor to the electronic control unit in a communication window KFn-1, KFn etc. within the following measuring window Mn, Mn+1 etc. The sensor varies the starting instant of the communication window independently so that an interfering signal S(n-1), S(n) etc. varies its temporal position and can be recognized as such.

Description

Title

Variable communication window for a data transmission from a sensor to a control device

The present invention relates to a method for data transmission between a sensor, in particular an ultrasonic sensor, on the one hand and a control and evaluation device on the other hand. Furthermore, the present invention relates to a sensor which is adapted to carry out such a method.

Prior art

Sensors, in particular ultrasonic sensors, are already prior art. Furthermore, methods for transmitting data between an ultrasonic sensor on the one hand and a control device on the other hand are known from the prior art. For example, the patent specification DE 10 2011 121 463 A1 discloses a method for communication between a sensor, in particular an ultrasonic sensor, and a control device, in which method data is transmitted by adjusting the amplitude of an electric voltage applied to the data line from a reference value to an amplitude value different from the reference value.

Ultrasound-based measuring systems are used to measure a distance to an object situated in front of a sensor. The sensors used are based on a pulse/echo method. In this operation the sensor emits an ultrasonic pulse and measures the reflection of the ultrasonic pulse (echo) caused by an object. The distance between sensor and object is then calculated via the measured echo propagation time and the speed of sound.

Modern ultrasonic sensors convert the received echo signal in the sensor by an analog-digital converter (also referred to as A/D converter below) into the digital domain and process the received signals by appropriate signal processing devices. The echo information is then transmitted digitally to an electronic control unit (ECU). The transmission of this data according to the prior art takes place in a specified dedicated communication window either a) after the last measuring cycle or b) during the next measuring cycle.

The variant a) involves an additional break in the measuring operation and results in a lower update rate of the environment, which results in a reduction of the measuring dynamics of the system. Generally, the variant b) is therefore preferred. However, it is then critical if the data transmission results in interference in the receiving channel during the measuring operation.

In 6th generation ultrasonic sensors, a current-modulated data transmission was developed, instead of a voltage-modulated data transmission. The interference occurring is thereby reduced, so that it is assumed that a data transmission during the measuring operation is fundamentally possible.

Disclosure of the invention

There is disclosed a method for data transmission between a sensor, in particular an ultrasonic sensor, on the one hand and an electronic control and evaluating device (also referred to as ECU below) on the other hand, in which method echo information produced by the sensor is transmitted from the sensor to the ECU in a communication window. In doing so, the sensor varies the communication window independently.

Furthermore, there is disclosed a sensor which is adapted to carry out such a method.

Thus, interference in the receiving channel, possibly caused by the data transmission during a measuring operation, is minimised by the invention, so that this inference has no or only little influence on the quality of the echo information to be evaluated. According to the invention, it is thus possible on the one hand to prevent this interference from erroneously being interpreted as object echoes (so-called "false positives"), and on the other hand from masking genuine object echoes (so-called "false negatives").

The subclaims show preferred developments of the invention.

In a preferred embodiment, the communication window is varied from one measuring cycle to a next measuring cycle.

The variation of the communication window takes place preferably stochastically or according to a predetermined sequence .

Preferably the communication window lies within a measuring window of a following measuring cycle. A range of the variation of the communication window is preferably parametrically changeable, resulting in the advantage that the data transmission from the sensor to the ECU can be adjusted to changed external conditions.

The communication window is varied by the sensor preferably by varying starting instants of the communication window by the sensor.

Furthermore, preferably the variation of the starting instants of the communication window is greater than a variation of capture windows in upper threshold filter layers of the ECU, the variation relating to starting instants and/or lengths. The capture windows of the upper threshold filter layers are usually varied only with the travelling speed, i.e. they are larger at higher speeds than at lower speeds. In this case, a capture window serves the purpose that an echo which has occurred can confirm a previously measured echo of the sensor if the difference of the echo distances lies within the capture window. Preferably, for certain signal processing functions in the upper threshold layers, only confirmed echoes are further processed, for example for a trilateration.

An essential advantage of the present invention is that the influence of interference in the receiving channel can be eliminated by the described type of variation of the communication window. Cases in which interference is recognised as false object echoes or in which interference masks genuine object echoes can thus be prevented.

Furthermore, in preferred embodiments the sensor is an ultrasonic sensor which is adapted to carry out the disclosed method. Further, the sensor may, for example, be an electromagnetic sensor, a capacitive sensor or another sensor which in the same way as the ultrasonic sensor has the problem that a data transmission from the sensor to a control device can influence a measuring result of the sensor .

Brief description of the drawing(s)

Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawing, in which:

Figure 1 is an exemplary schematic representation of an ultrasonic sensor;

Figure 2 is exemplary time profiles of measuring cycles including communication windows according to the prior art;

Figure 3 is exemplary time profiles of measuring cycles including communication windows according to an embodiment of the present invention.

Embodiments of the invention

Figure 1 shows a schematic representation of an ultrasonic sensor 100. The ultrasonic sensor 100 has an ultrasonic pulse transmitter 110, an echo receiver 120, an A/D converter 130 and a digital signal processing device 140. The ultrasonic pulse transmitter 110 emits an ultrasonic pulse 115, and the echo receiver 120 receives reflections 125 of the ultrasonic pulse (echoes) caused by an object.

An output of the echo receiver 120 and optionally of the ultrasonic pulse transmitter 110 are connected to an input of the A/D converter 130, so that the A/D converter 130 can convert the received echo signal and optionally required signals from the ultrasonic pulse transmitter 110 into the digital domain. An output of the A/D converter 130 is connected to an input of the digital signal processing device 140, which digitally processes the received signals. An output of the digital signal processing device 140 is connected to an input of an ECU 150 via a connection 145. Via this connection 145, results of an echo signal measurement in relation to the emitted ultrasonic pulses from the ultrasonic sensor 100 are transmitted to the ECU 150.

Figure 2 shows exemplary time profiles of four measuring cycles, a first measuring cycle Mn, a second measuring cycle Mn+1, a third measuring cycle Mn+2 and a fourth measuring cycle Mn+3, according to the prior art. As can be seen from Figure 2, a measuring cycle has respectively a time window for a measurement (also referred to as measuring window MF below), which lasts from a measuring starting instant tMS to a measuring finishing instant tME-Further, a measuring cycle M has respectively a time window for data transmission from the ultrasonic sensor 100 to the ECU 150 (also referred to as communication window KF below), the communication window KF lasting from a communication starting instant tKs to a communication finishing instant tKe and in each measuring cycle M lying respectively at a specified, same place within the measuring window MF. That is to say, the communication starting instant tKs and the communication finishing instant tke are the same for each communication window KF. Further, in this case a communication window KFn belonging to a measuring cycle Mn lies respectively in a measuring cycle Mn+1 following the measuring cycle Mn. In the example shown in Figure 2, accordingly a preceding communication window KFn-1 lies within the first measuring window MFn, a first communication window KFn lies within the second measuring window MFn+1, a second communication window KFn+1 lies within the third measuring window MFn+2, and a third communication window KFn+2 lies within the fourth measuring window MFn+3.

As can further be seen from Figure 2, within a measuring window an object echo OE(n), OE(n+l), etc. is respectively received as a result of a reflection of a previously emitted ultrasonic pulse. An associated signal converted into the digital domain (and optionally processed) is transmitted during the communication window KFn in the following measuring cycle Mn+1 as a respective first echo signal ES(n), second echo signal ES(n+l), etc. from the ultrasonic sensor 100 to the ECU 150.

As can further be seen from Figure 2, within a communication window KF a first interfering signal S(n), a second interfering signal S(n+1), etc. respectively occurs. An associated signal converted into the digital domain (and optionally processed) is then transmitted during the communication window KF in the following measuring cycle M, for example, as a respective false signal (e.g. false positive) FS(n), FS(n+l), etc. In the case where the interfering signals are produced, for example, in the receiving channel of the ultrasonic sensor and have a repeating pattern, these interfering signals may be erroneously interpreted as object echoes, in particular if the communication window is fixed in time and an interfering signal is always displayed at the same time. In another example, the interfering signals can result in real object echoes being masked out.

Figure 3 shows exemplary time profiles of four measuring cycles, a first measuring cycle Mn, a second measuring cycle Mn+1, a third measuring cycle Mn+2 and a fourth measuring cycle Mn+3, according to an embodiment of the present invention. Similar to Figure 2, a measuring cycle M has respectively a measuring window MF which lasts from an instant tMS to an instant tME· Further, a measuring cycle M has respectively a communication window KF, and a communication window KFn belonging to a measuring cycle Mn lies respectively in a measuring cycle Mn+1 following the measuring cycle Mn. In the example shown in Figure 3, accordingly a preceding communication window KFn-1 lies within the first measuring window MFn, a first communication window KFn lies within the second measuring window MFn+1, a second communication window KFn+1 lies within the third measuring window MFn+2, and a third communication window KFn+2 lies within the fourth measuring window MFn+3.

In contrast to Figure 2, however, in a method according to the present invention, as shown in Figure 3, the starting instants of the communication windows KF are varied according to the invention by the ultrasonic sensor 100. Thus, a preceding communication window KFn-1 which lies before the first communication window KFn, and which lies in the first measuring cycle Mn, has a first starting instant tKs; a communication window KFn has a second starting instant tKs' which in the example shown lies earlier in the second measuring cycle Mn+1 than the first starting instant tKs in the first measuring cycle Mn, a communication window KFn+1 has a third starting instant tKs" which in the example shown lies earlier in the third measuring cycle Mn+2 than the first starting instant tKs in the first measuring cycle Mn and later than the second starting instant tKs' in the second measuring cycle Mn+1; and a communication window KFn+2 has a fourth starting instant tKs'" which in the example shown lies earlier in the fourth measuring cycle Mn+3 than the preceding starting instants tKs/ tKs' and tKs" in respective preceding measuring cycles Mn, Mn+1 and Mn+2.

As can further be seen in Figure 3, for example a detected interfering signal S(n-l), S(n), S(n+1) etc. is thereby varied in its temporal occurrence, in particular if the interfering signal is an interfering signal itself caused regularly by the data transmission. Associated digital signals from the digital signal processing device are thus transmitted as different measuring results FS(n-l), FS(n), FS(n+l), etc. to the ECU 150. As an advantageous effect of the variation of the communication window, thus for example, a pattern of an interfering signal which is produced upon the data transmission from the ultrasonic sensor 100 to the ECU is changed in time, with the result that an interfering signal can be recognised as such.

The variation of the communication window can take place advantageously stochastically or according to a predetermined sequence. Moreover, it is advantageous if the communication window can be varied from one measuring cycle to a next measuring cycle.

It is further advantageous if the range of a variation of the communication window can be changed by an external parameterisation. Thus, advantageously a range of a variation of the communication window can be adjusted to a speed of a vehicle in which the ultrasonic sensor is situated. For example, the range can be increased at a higher speed.

Further, advantageously the starting instants of the communication window are more highly varied than the capture windows of upper threshold layers, which serve to filter out any erroneous object echoes which still occur, filters from the prior art with predefined, mostly speed-dependent capture windows being used.

An ultrasonic sensor according to an embodiment of the present invention is designed to vary the communication window independently, without the need for an associated communication process with the ECU. Undesired measuring interruptions can thereby be avoided.

Besides the above written disclosure, for the further disclosure of the invention, reference is hereby additionally made to the representations in Figures 1 to 3.

Claims

1. Method for a data transmission from a sensor (100) to an electronic control unit (150), in which method echo information produced by the sensor is transmitted from the sensor to the electronic control unit in a communication window, characterised in that the sensor varies the communication window independently.

2. Method according to Claim 1, characterised in that the communication window is varied from one measuring cycle to a next measuring cycle.

3. Method according to Claim 1 or 2, characterised in that the variation of the communication window performed by the sensor takes place stochastically or according to a predetermined sequence.

4. Method according to one of Claims 1 to 3, characterised in that the communication window lies in a measuring window of a following measuring cycle.

5. Method according to one of Claims 1 to 4, characterised in that a range of the variation of the communication window is parametrically changeable.

6. Method according to one of Claims 1 to 5, characterised in that the communication window is varied by the sensor preferably by varying the starting instants of the communication window by the sensor.

7. Method according to one of Claims 1 to 6, characterised in that the variation of the starting instants of the communication window is greater than the variation of capture windows in upper threshold filter layers.

8. Method according to one of Claims 1 to 7, characterised in that the sensor is an ultrasonic sensor.

9. Sensor which is adapted to carry out the method according to one of the preceding claims.

10. Sensor according to Claim 9, characterised in that the sensor is an ultrasonic sensor.

11. Method for a data transmission, substantially as herein described with reference to and as shown in the accompanying drawings .