DE102008044367A1 - Intelligent sensor for a motor vehicle, detection system and method for transmitting a sensor signal - Google Patents

Abstract

The invention relates to an intelligent sensor for a motor vehicle, which is designed to detect a parameter, in particular an acceleration or a distance, and to generate a data record representing the parameter. The sensor also includes a sensor clock that is configured to generate a clock signal that represents a clock for transmitting the data set. The sensor is also configured to communicate with a master according to a communication protocol and to transmit the data set to the master using a communication protocol in response to a timing clock generated by the sensor clock during a time window formed by a period of time. According to the invention, the sensor clock generator is designed to change the clock frequency of the clock for transmitting the data set as a function of a clock signal representing a clock frequency of the control signal. For this purpose, the sensor has a clock regulator which is designed to generate the carrier signal such that the clock frequency of the sensor clock generator corresponds to the determined clock frequency of the master time clock.

Description

State of the art

The The invention relates to an intelligent sensor for a motor vehicle. The sensor is designed to have at least one parameter, in particular an acceleration, a speed or a distance to capture and generate a record containing the parameter represents. The sensor also has a sensor clock on, wherein the sensor clock is formed, a clock signal to generate a timing for transmitting the Represented record. The sensor also has a the processing unit connected to the sensor clock. The processing unit is formed according to a communication protocol with to communicate to a master and using the communication protocol in response to a signal generated by the sensor clock Timed the record during a period of time time window to be transmitted to the master.

From the US 2007 0239 950 A1 a device is known which has a primary and a secondary control unit. The primary and secondary controllers may each communicate with each other and synchronize a time clock for communicating using a time server.

Disclosure of the invention

According to the invention formed in the sensor of the type mentioned above, the sensor clock, the clock frequency of the clock for transmitting the record depending on a the clock frequency of the clock to change the representative control signal. The sensor has for this purpose a clock regulator, which is designed, one of the master according to the communication protocol transmitted master signal generated by a master clock at least in time sections to detect and a clock frequency of the master time clock with which generates the master signal has been. The clock regulator is formed, the carrier signal to generate such that the clock frequency of the sensor clock the determined clock frequency of the master time clock corresponds. Thereby is advantageously achieved that the sensor clock inexpensive and / or can be provided at low cost.

One Master within the meaning of the teaching of the invention one for communicating according to a communication protocol trained receiver or transceiver, a controller a motor vehicle, a control device of a fieldbus or be a host of a communication system of a motor vehicle.

In a preferred embodiment, the sensor clock to generate the clock, an RC element comprising at least one Resistance and at least one capacity up. Through the RC element can be the sensor clock compared to a quartz oscillator be provided advantageously low cost.

In a preferred embodiment, the sensor clock generator for generating the timing, an LC element comprising at least one Inductance and a capacity up. By the LC element can be the sensor clock compared to a quartz oscillator be provided advantageously low cost.

In In a preferred embodiment, the sensor has a for connecting to a data bus formed interface. The sensor is designed to record the data via the interface and transfer the data bus to the master. exemplary Embodiments of an interface for connection with a data bus are an interface for connecting to a Fieldbus, or a PSI5 interface (PSI5 = peripheral sensor interface 5) in bus configuration. A fieldbus is, for example, a LIN bus (LIN = Local Interconnect Network), CAN Bus (CAN = Controller Area Network), MOST (Media-Oriented Systems Transport) bus, Flex-RayTM bus, TTP bus (TTP = Triggered-Time-Protocol) or an Interbus.

In an advantageous embodiment, the clock regulator a frequency divider, wherein the frequency divider is formed, the clock frequency of the master time clock and / or the clock frequency of the sensor clock each according to a duty cycle to divide and the control signal depending on one Difference of the division result to produce.

Thereby Advantageously, the clock control can be done with high accuracy.

In In a preferred embodiment, the sensor is a distance sensor, which is designed as a parameter, in particular by means of Doppler interferometry or Pulse Echo Runtime detection to detect a distance. For example The distance sensor can measure the distance by means of ultrasound or electromagnetic Detect rays.

Of the Sensor is for example an acceleration sensor for an airbag, which is formed as a parameter in particular by means of at least one piezoelectric element acceleration to capture.

In an advantageous embodiment is the sensor is a current sensor, which is designed to detect an electric current as a parameter. For example, the current sensor may be part of an electric window lift and detect a current increase of a window lift motor.

Further advantageous embodiments for a sensor are a temperature sensor, a voltage sensor or a pressure sensor.

The The invention also relates to a detection system for a motor vehicle. The detection system comprises at least one sensor of the aforementioned Art. The detection system also has one to communicate with the at least one sensor formed master, wherein the Master has a processing unit. The processing unit is formed according to the communication protocol to generate the master signal and a parameter representing the parameter Receive record. The master also has a clock, which is designed to generate the master time clock. Advantageous the detection system may be part of a motor vehicle.

The The invention also relates to a method for transmitting a Sensor signal to a master in a motor vehicle. In the process is by means of at least one sensor, preferably a plurality of sensors, at least one parameter, in particular an acceleration, a Speed or a distance or a combination of these and a data record representing the parameter generated.

Further is transmitted by the sensor one time clock to transmit of the data record representing clock signal, wherein the sensor according to a communication protocol communicates with a master and the record under application of the communication protocol depending on a timer generated by the sensor during a by a Time segment formed time frame transmitted to the master becomes. By means of the sensor one of the master according to the Communication protocol transmitted master signal at least in sections detected and by means of the sensor a clock frequency of a master clock determined with which the master signal has been generated. Next will by means of the sensor, a clock frequency of the clock for transmitting of the data set as a function of the clock frequency the time clock for transmitting the record representing Changed control signal, the control signal generated in such a way is that the clock frequency of the timing of the sensor of the determined Clock frequency of the master time clock corresponds.

The Invention will now be described below with reference to figures and others Embodiments described.

1 shows an embodiment of a detection system for detecting at least one parameter by means of at least one sensor;

2 shows an embodiment of a processing unit with a frequency divider for in 1 illustrated detection system;

3 shows an exemplary embodiment of a signal sequence that has been generated according to a communication protocol;

4 shows an embodiment of a burst generated according to a communication protocol of a PSI5 bus;

5 shows an embodiment of a method for transmitting a sensor signal to a master in a motor vehicle.

1 schematically shows an embodiment of a detection system 2 with a sensor 1 , The sensor 1 is in this embodiment, an ultrasonic sensor, which is formed, a distance 19 by means of a transmitted ultrasound 15 and a back-reflected ultrasound 17 capture.

The sensor 1 has a processing unit 3 on. The processing unit 3 has a sensor clock 5 , a clock control 7 and a clock detection device 9 on. The clock detection device 9 has an entrance 18 for a master signal. The processing unit 3 also has an interface 10 which, in this embodiment, is an interface for connection to a fieldbus.

the interface 10 is input side with an input 12 connected for a distance signal. The entrance 12 is via a connection line 42 with an ultrasonic sensor 14 of the sensor 1 connected. The ultrasonic sensor 14 is formed, ultrasonic waves 15 and from an object, such as a vehicle 30 , reflected back ultrasonic waves 17 to receive and generate a distance signal representing the distance 19 between the ultrasonic sensor 14 and the vehicle 30 represents. The ultrasonic sensor 14 For example, the distance signal can be generated by means of Doppler interferometry or pulse-echo transit time detection. Advantageously, a time base for detecting the pulse-echo transit time by one of the sensor clock 5 generated clock signal may be formed. The ultrasonic sensor 14 is input side via a connecting line 36 with the sensor clock 5 connected via the connecting line and the clock signal to form the time base receive.

The detection device 2 also has a master 20 on. The master 20 has a processing unit 22 and one with the processing unit 22 connected clock 25 on. The master 20 is formed according to a communication protocol - for example, a communication protocol of a fieldbus - with the sensor 1 to communicate and from the sensor 1 to receive a data set containing a parameter, in this embodiment the distance 19 represents.

The master 20 is via a data bus 23 with an exit 21 of the sensor 1 connected. The data bus can be formed, for example, by the field bus, in particular a LIN bus, a CAN bus or a MOST bus. The exit 21 is about a connection 16 with the interface 10 connected. the interface 10 is on the input side via the connecting line 36 with the sensor clock 5 connected. The sensor clock 5 has, for example, an RC element. The sensor clock is designed, a clock signal 8th to generate, and this over the connecting line 36 issue. The clock signal 8th represents a timing for transmitting the data set to the master 20 ,

At the beginning of a transmission of the record from the sensor 1 to the master 20 can the clock 25 of the master 20 generate a timing for transmitting the aforementioned master signal according to the communication protocol and the master 20 can this over the data bus 23 , the exit 21 and the connection 16 to the interface 10 send. the interface 10 can the master signal through the connection 16 received and over the entrance 18 to the detection device 9 send. The detection device 9 is configured to detect the master signal at least in sections and to determine a clock frequency of the master time clock with which the master signal has been generated. In this embodiment, the master signal is by means of the master time clock of the clock 25 been generated.

The detection device 9 may for example be formed as a bit-time detection device, wherein the bit-time detection device is adapted to detect a bit rate and / or a bit duration, which is that of the clock 25 generated master time clock corresponds. The detection device 9 is configured to generate an output signal which corresponds to the master time clock of the clock generator determined using the master signal 25 corresponds and this output side via a connecting line 40 issue. The clock regulator 7 is on the input side via the connecting line 40 with the detection device 9 connected. The clock regulator 7 is on the output side via a connecting line 38 with the sensor clock 5 connected. The clock regulator 7 is on the input side via a connecting line 39 with the output of the sensor clock 5 connected and so can over the connecting line 39 the clock signal 8th receive. The clock regulator 7 is formed from the input side via the connecting lines 40 and 39 received signals form a difference, and depending on the difference - which is a difference in frequency between the over the connecting lines 39 and 40 received signals corresponds to - generate a control signal, and this output side via the connecting line 38 to the sensor clock 5 to send. The sensor clock 5 Thus, depending on the control signal, a clock frequency of the clock signal 8th to change. The control signal can be formed for example by a voltage. The sensor clock 5 For example, to generate the clock signal, it may have a resistance and a capacitance formed by a capacitance diode. The capacitance diode is designed to change its capacitance as a function of the control signal, in particular of a voltage.

the interface 10 is input side with the connection line 36 connected and can that by the regulator 7 changed clock signal 8th received, and in response to the clock signal 8th with the master 20 to communicate. In this way, advantageously, a frequency difference, between that of the clock 25 generated timing and that of the clock 5 generated clock at least partially or completely compensated.

2 schematically shows an embodiment of a processing unit 4 for the in 1 shown sensor 1 , The processing unit 4 can be in place of the processing unit 3 be used. The processing unit 4 has a sensor clock 50 , a clock control 6 , a bit-time detecting device 9 and an interface 10 on. the interface 10 is output side with an input 18 the bit-time detecting device 9 connected. The bit-time detection device 9 is on the output side via a connecting line 48 with the clock regulator 6 connected. The clock regulator 6 is on the output side via a connecting line 46 with a frequency divider 32 connected. The frequency divider 32 is on the input side via a connecting line 44 with the sensor clock 50 connected, and can over the connecting line 44 one from the sensor clock 50 generated clock signal 8th receive.

The frequency divider 32 is formed, the clock signal 8th to divide according to a predetermined division ratio and the output side, a clock signal 33 with a clock frequency corresponding to the division result. The frequency divider 32 is on the input side also via a connecting line 46 with the clock regulator 6 connected. The frequency divider 32 is formed, the division ratio in dependence on a via the connecting line 46 received control signal generated by the clock controller 6 , to change. The division ratio can be changed, for example, in steps N, for example according to the rule 1 / (900 + N), where N is between 0 and 200.

The frequency divider 32 is on the output side via a connecting line 52 with a frequency multiplier 34 connected. The frequency multiplier 34 is trained, one over the connecting line 52 on the input side received clock signal 33 multiplying by a predetermined ratio, for example, 1000: 1, and generating an output signal having a frequency corresponding to the multiplying result. The frequency of the clock signal 8th may for example be 1 megahertz. The frequency of the frequency multiplier 34 generated clock signal is then also 1 megahertz. The sensor clock 50 may for example have a frequency tolerance of +/- 5 percent. The frequency multiplier 34 can be formed for example by a PLL multiplier (PLL = Phase-Locked-Loop) or an FLL multiplier (FLL = Frequency-Locked-Loop).

the interface 10 is about the connection 16 with the exit 21 connected. the interface 10 can over the connection 16 receive the master signal, and - for example, in response to a synchronization signal - the master signal to the input 18 the bit-time detecting device 9 send. The clock regulator 6 can over the connecting line 48 that from the bit time detector 9 generated output signal representing the clock frequency of the master time clock received. The clock regulator 6 is also on the input side via a connecting line 51 with the frequency multiplier 34 connected and so can the output signal of the frequency multiplier 34 receive. The clock regulator 6 is formed from the over the connecting line 51 received signal and the over the connecting line 48 received signal to form a frequency difference and in the case of a frequency difference to generate a control signal with which the frequency difference compensated who can and this via the connecting line 46 to the frequency divider 32 to send. The clock regulator 6 may for example be a proportional integral rule. This way you can use the connection line 51 which also with the interface 10 connected, one at the entrance 12 for a sensor signal received record with a clock frequency to the output 21 are sent, which corresponds to the clock frequency of the master time clock.

The processing unit 3 in 1 and / or the processing unit 4 in 2 can each be at least formed by a part of a microprocessor, a microcontroller, an FPGA (FPGA = Field Programmable Gate Array), each controlled by a control program, in particular computer program product. Also conceivable is an embodiment in which the processing unit 3 and or 4 is realized by an ASIC (Application Specific Integrated Circuit).

3 shows an embodiment of a signal sequence, which has been generated according to a LIN communication protocol. The signal sequence is within a time interval 63 sent and includes a header 59 and an answer 61 , The header 59 includes a signal burst 60 which has a bit string. The signal burst 60 follows a time interval 62 , representing a time interval between two bytes. Thereafter, an identification record 64 sent, with which a sensor to be read is addressed. After the identification record 64 begins the response of the by means of the identification record 64 addressed sensor. The answer 61 has a time interval at the beginning 69 on after records sent by the sensor, each followed by a time interval of the length of the time interval 62 be sent. The answer 61 includes in this embodiment a record 65 , a record 66 and a record 67 , The records 65 . 66 and 67 each have the duration 68 on and off of a record 70 representing a checksum completed. The records 65 . 66 and 67 each represent a parameter which, by means of the data set 64 addressed sensor has been detected. The duration 68 forms a time window in which a data record can be transmitted. The time interval 61 forms a time window in which the records 65 . 66 , and 67 can be transmitted.

4 shows an embodiment of a signal sequence 72 which has been sent on a data bus. Shown is a timeline 74 and an amplitude axis 76 , The signal sequence 72 has periodically and alternately successive data sets and synchronization pulses. In this embodiment, a synchronization pulse follows 82 a record 81 , On the synchronization pulse 82 follows a record 83 , On the record 83 follows a synchronization pulse 84 followed by a record 85 , The synchronization pulses of the signal sequence 72 are sent at a clock frequency generated by a clock and each have a signal amplitude 78 on. The data records each have a maximum amplitude 80 on.

5 shows an embodiment of a method for transmitting a sensor signal to a master in a motor vehicle, for example by means of in 1 illustrated detection system.

At one step 80 of the method, a parameter, in particular an acceleration or a distance, is detected by means of a sensor and a data record representing the parameter is generated. At one step 82 the sensor generates a clock signal representative of a timing for transmitting the data set and the sensor communicates according to a communication protocol with a master and using the communication protocol in response to a time clock generated by the sensor, the data set being active during a time window formed by a period of time the master is transmitted.

At one step 84 a master signal sent by the master according to the communication protocol is detected by the sensor at least in a time-wise manner and by means of the sensor a clock frequency of a master time clock is determined with which the master signal has been generated.

At one step 86 the sensor changes a clock frequency of the clock pulse for transmitting the data set as a function of a control signal representing a clock frequency, wherein the control signal is generated by means of the sensor such that the clock frequency of the clock of the sensor corresponds to the determined clock frequency of the master clock.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 20070239950 A1 [0002]

Claims (10)

Intelligent sensor ( 1 ) for a motor vehicle, wherein the sensor ( 1 ) is adapted to capture a parameter and a data set ( 65 . 66 . 67 ), which represents the parameter, and wherein the sensor ( 1 ) a sensor clock ( 5 ), which is designed to generate a clock signal, wherein the clock signal has a time clock for transmitting the data set ( 65 . 66 . 67 ), and wherein the sensor ( 1 ) one with the sensor clock ( 5 ) connected processing unit ( 3 . 10 ) configured to communicate with a master according to a communication protocol and using the communication protocol in response to one of the sensor clocks ( 5 ) generate the data record ( 65 . 66 . 67 ) during a time window formed by a period of time ( 61 . 68 ) to the master, characterized in that the sensor clock ( 5 ) is formed, the clock frequency of the clock for transmitting the data set ( 65 . 66 . 67 ) in response to a control signal representing the clock frequency of the clock cycle and the sensor ( 1 ) a clock controller ( 7 ), which is formed, a master signal transmitted by the master according to the communication protocol, generated by means of a master time clock ( 60 ) to detect at least a period of time and a clock frequency of the master time clock ( 25 ), with which the master signal has been generated, and to generate the control signal such that the clock frequency of the sensor clock ( 5 ) of the determined clock frequency of the master time clock ( 25 ) corresponds. Sensor ( 1 ) according to claim 1, characterized in that the sensor clock ( 5 ) for generating the timing, an RC element comprising at least one resistor and at least one capacitor. Sensor ( 1 ) according to claim 1, characterized in that the sensor clock ( 5 ) for generating the timing, an LC element comprising at least one inductor and a capacitor. Sensor ( 1 ) according to one of the preceding claims, characterized in that the sensor ( 1 ) one for connection to a data bus ( 23 ) trained interface ( 10 . 21 ), and is adapted to the data set ( 65 . 66 . 67 ) via the interface ( 10 . 21 ) and the data bus ( 23 ) to the master ( 20 ) transferred to. Sensor ( 1 . 4 ) according to one of the preceding claims, characterized in that the clock regulator ( 6 ) a frequency divider ( 32 ), wherein the frequency divider ( 32 ), the clock frequency of the master time clock ( 25 ) and / or the clock frequency of the sensor clock ( 50 ) in each case according to a duty ratio and to generate the control signal in response to a difference of the division result. Sensor ( 1 ) according to one of the preceding claims, characterized in that the sensor ( 1 ) is a distance sensor, which is designed as a parameter by means of pulse-echo transit time detection a distance ( 19 ) capture. Sensor ( 1 ) according to one of the preceding claims, characterized in that the sensor ( 1 ) is an acceleration sensor for an airbag, which is designed to detect an acceleration as a parameter. Sensor ( 1 ) according to one of the preceding claims, characterized in that the sensor is a current sensor which is designed to detect an electric current as a parameter. Detection system ( 2 ) for a motor vehicle, with at least one sensor ( 1 ) according to one of the preceding claims and with a device for communicating with the at least one sensor ( 1 ) trained Master ( 20 ), whereby the master ( 20 ) a processing unit ( 22 ), which is designed to generate the master signal according to the communication protocol and a data record representing the parameter ( 65 . 66 . 67 ), and the master ( 20 ) a clock ( 25 ), which is formed, the master time clock ( 60 ) to create. Method for transmitting a sensor signal ( 65 . 66 . 67 ) to a master ( 20 ) in a motor vehicle, in which by means of at least one sensor ( 1 ) a parameter, in particular an acceleration, a speed or a distance ( 19 ) and a data set representing the parameter ( 65 . 66 . 67 . 81 . 83 . 85 ) is generated, and in which by means of the sensor ( 1 ) is generated a clock signal representing a timing for transmitting the data record, and in which the sensor ( 1 ) according to a communication protocol with a master ( 20 ) communicates using the communication protocol in dependence on one of the sensors ( 1 ) time record of the record ( 65 . 66 . 67 . 81 . 83 . 85 ) during a time window formed by a period of time ( 61 . 68 ) to the master ( 20 ), characterized in that in the method by means of the sensor ( 1 ) one of the master ( 20 ) according to the communication protocol sent master signal ( 60 ) is detected at least in sections, and by means of the sensor ( 1 ) a clock frequency of a master time clock ( 25 ) is determined, with which the master signal ( 60 ) and the sensor ( 1 ) one Clock frequency of the clock for transmitting the data set ( 65 . 66 . 67 . 81 . 83 . 85 ) as a function of a control signal representing the clock frequency of the clock for transmitting the data set, and by means of the sensor ( 1 ) the control signal is generated such that the clock frequency of the clock ( 5 ) of the transmitter ( 1 ) of the determined clock frequency of the master time clock ( 25 ) corresponds.