Method and Apparatus for Operating a Sensor System, Sensor System

Abstract

A method for operating a sensor system for operating a sensor system includes electrically connecting sensors of a plurality of sensors to one another with a bus system. The method further includes communicating with the plurality of sensors over the bus system using a control device. The method further includes controlling one or more of the sensors of the plurality of sensors to transmit data to the control device with a predefinable bit width. The method further includes controlling one or more of the sensors of the plurality of sensors to transmit data to the control device with a reduced bit width. The sensor system includes the plurality of sensors and the control device.

Claims

1. A method for operating a sensor system for a motor vehicle, the sensor system having a plurality of sensors and a control device, the method comprising: electrically connecting sensors of the plurality of sensors to one another with a bus system; communicating with the plurality of sensors over the bus system using the control device; controlling one or more of the sensors of the plurality of sensors to transmit data to the control device with a predefinable bit width; and controlling one or more of the sensors of the plurality of sensors to transmit data to the control device with a reduced bit width.

2. The method as claimed in claim 1, further comprising: controlling a respective sensor of the plurality of sensors to transmit the data with a bit width of 5 bits or less.

3. The method as claimed in claim 1, further comprising: controlling at least one sensor of the plurality of sensors to transmit the data with a reduced resolution in order to reduce the bit width.

4. The method as claimed in claim 1, further comprising: controlling at least one sensor of the plurality of sensors to preprocess the data before the data are transmitted to the control device in order to reduce the bit width.

5. The method as claimed in claim 1, further comprising: controlling at least one sensor of the plurality of sensors to compare captured data with at least one threshold value.

6. The method as claimed in claim 1, further comprising: controlling at least one sensor of the plurality of sensors to filter, integrate, and/or derive the data before transmitting the data to the control device.

7. The method as claimed in claim 1, further comprising: controlling at least one sensor of the plurality of sensors to compare data with a plurality of threshold values; and increasing a bit value to be transmitted based on a number of exceeded threshold values.

8. The method as claimed in claim 1, wherein the control device communicates with the sensors of the plurality of sensors using a PSI5 protocol.

9. The method as claimed in claim 1, further comprising: controlling at least one sensor of the plurality of sensors to alternately transmit the data with the reduced resolution and to preprocess the data in order to reduce the bit width before transmitting the data to the control device.

10. The method as claimed in claim 1, further comprising: controlling at least one sensor of the plurality of sensors to alternately vary the bit width.

11. The method as claimed in claim 1, wherein the control device is configured to control one or more of the sensors of the plurality of sensors to (i) transmit data to the control device with the predefinable bit width, and (ii) to transmit data to the control device with a reduced bit width.

12. A sensor system for a motor vehicle comprising: a conduction band; a plurality of sensors arranged on the conduction band and configured to make electrical contact with the conduction band, a bus system configured to connect electrically sensors of the plurality of sensors; and a control device connected to the conduction band configured to communicate with the sensors of the plurality of sensors using the bus system, the control device configured to operate the plurality of sensors by controlling one or more of the sensors of the plurality of sensors to transmit data to the control device with a predefinable bit width, and controlling one or more of the sensors of the plurality of sensors to transmit data to the control device with a reduced bit width.

13. The sensor system as claimed in claim 1, further comprising: a contact apparatus configured to connect the plurality of sensors to the control device.

14. The method as claimed in claim 1, wherein the plurality of sensors are arranged on a conduction band.

15. The method as claimed in claim 1, wherein all of the plurality of sensors are configured to transmit the data with a reduced bit width.

16. The method as claimed in claim 10, wherein at least one of the sensors is configured to alternately vary the bit width.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The disclosure shall be explained in more detail below on the basis of the drawing.

[0019] FIG. 1 shows a simplified illustration of an advantageous sensor system.

DETAILED DESCRIPTION

[0020] FIG. 1 shows a simplified illustration of an advantageous sensor system 1. The sensor system 1 has a plurality of sensors 2 which are in the form of pressure sensors, acceleration sensors or rate-of-rotation sensors, for example. The sensors 2 are arranged on a conduction band 3 which is used to make electrical contact with all sensors 2 for the purpose of supplying energy, on the one hand, and transmitting signals, on the other hand. For this purpose, provision is made in the present case for the conduction band 3 to make contact with or operate the sensors 2 by means of a bus system 4 which is shown in FIG. 1 by means of a simplified connecting line. At a free end 5 of the conduction band, the latter has a contact apparatus 6, preferably in the form of a plug contact, which is or can be used to connect the sensor system 1 to a control device 7 indicated here. The control device 7 receives data signals from the sensors 2 by means of the bus system 4 and evaluates said signals. In the present case, communication takes place by means of the PSI5 protocol in which data captured by the sensors are transmitted to the control device 7 by means of bit-coded data packets. In this case, a data packet advantageously comprises two start bits, a predetermined number of data bits which describe the actual bit value to be transmitted, and an end bit or parity bit.

[0021] In contrast to previously known solutions, the sensors 2 are controlled, in particular by the control device 7, to transmit the data packets with a reduced bit width. The bit width of the data transmission results from the number of bits in the respective data packet. For this purpose, provision is made in the present case for the data to be transmitted using 1 to 10 bits, in particular using 5 bits or 3 bits. As usual, the data then also include 1 to 2 start bits and the parity bit, thus resulting in a total bit width of 4 bits to 13 bits.

[0022] The number of bits is advantageously reduced by means of at least one of the two methods described below:

[0023] A first exemplary embodiment provides for the output signals from the sensors 2 to be passed to the communication bus or the bus system 4 with a diminished resolution, the bit width being reduced for each sensor 2. An example of such a reduction in the bit width is, for example, the halving of the bits for each sensor on the PSI5 communication bus. As a result, the communication bus or the bus system 4 is used less by the sensors 2, with the result that additional sensors 2 can be added to the communication bus 4. Increasing the number of sensors maintains the measurement accuracy of the sensor system 1 despite a reduced bit width, in which case the advantage of more sensor values overall and therefore a particularly high monitoring width being achieved by the sensors 2 is achieved on account of the increased number of sensors.

[0024] A second exemplary embodiment provides for the bit width to be reduced by virtue of the sensors 2 already preprocessing the data signals output to the communication bus by the sensors 2. This reduces the bit width of the transmission to 3 bits per sensor, in particular. Preprocessed sensor signals, for example, are transmitted in these 3 bits. For example, the pressure or acceleration rates of one of the sensors 2 can already be compared in the sensor with predetermined threshold values corresponding to a signal strength, for example. In particular, provision is made for the captured data signals from the respective sensor to be compared with a plurality of threshold values which correspond to different signal strengths. For this purpose, the captured data signals are advantageously filtered, integrated or derived in the respective sensor 2. The more threshold values are exceeded by the preprocessed signal from the sensor, the higher the incrementation of the bit value defined by the 3 bits. If, for example, none of the threshold values is exceeded, 000 is determined as the bit value. If a first threshold value is exceeded, 001 is determined as the bit value. If a second threshold value which is higher than the first threshold value is exceeded, 010 is determined as the bit value. If a third threshold value which is higher than the second threshold value is exceeded, 100 is output as the bit value.

[0025] It goes without saying that further information and further features of the respective sensor 2 can also be represented in the 3 bits. In the present case, the 3 bits can be understood as an example and may vary depending on requirements.

[0026] Another exemplary embodiment provides for a combination of the two methods described above to be carried out by the sensor system 1. In particular, provision is made for a pair of the sensors 2 to place their data on the communication bus with a lower resolution and for the remaining sensors to preprocess the captured data as described in order to reduce the number of bits. Another exemplary embodiment provides for the sensors 2 of the sensor system 1 to transmit their data to the communication bus in a manner alternating between the two methods described, with the result that the respective sensor 2 outputs the data once with a lower resolution and transmits preprocessed data to the communication bus in the next data set.

[0027] The advantage of the described method is that more sensors than before can be arranged on the conduction band 3 and can be used by the bus system 4. The interfaces and the cabling complexity are considerably reduced as a result, in particular for applications in which a large number of sensors is required. Despite the reduced number of bits, the sensors 2 provide a residual performance which allows the control device 7 to comprehend the basic signal profile of the respective output signal. Even if the information is no longer as accurate as before, this disadvantage is more than just compensated for by the increased number of sensors. Therefore, the sensor system 1 advantageously has more than three, in particular more than four, sensors, which is not possible with previous operating methods on account of the use of the communication bus 4.