JP2011239081A - Signal processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a delay time generated from when a request signal is received from an electronic control device to when digital data is transmitted to the electronic control device.SOLUTION: When a communication apparatus 24 receives a request signal from an electronic control device 10, digital data stored in a memory 23 is transmitted to the electronic control device 10. In addition, a communication cycle estimating part 25 estimates a timing to receive the request signal next time, based on the timing when the request signal is received last time but one and the timing when the request signal is received last time. A timing generating part 26 calculates a timing obtained by subtracting a processing time from the timing when the request signal is received next time, and carries out A/D conversion of a sensor signal by an A/D converter 22 at the calculated timing. The A/D-converted sensor signal (digital data) is stored in the memory 23 to be used in the next transmission.

Description

  The present invention relates to a signal processing device that converts an output signal of a sensor into digital data.

  Conventionally, as this type of device, a sensor for detecting a state of a control target such as an in-vehicle engine, an A / D converter for A / D converting a sensor signal acquired from the sensor into digital data, and an A / D There is a control system including an electronic control device that controls a control target based on digital data output from a converter (see, for example, Patent Document 1).

JP 2005-167972 A

  In the above control system, when a control target is controlled using a plurality of sensors, the sensor signal is A / D converted for each sensor to obtain digital data, and the control target is controlled based on the digital data for each sensor. It will be necessary.

  If there is a time difference in the timing for each sensor that acquires sensor signals from a plurality of sensors, even if each of the plurality of sensor signals is A / D converted, the accuracy of the digital data varies from sensor to sensor. For this reason, it is important to make the timings for A / D converting sensor signals from a plurality of sensors as close as possible.

  Here, if the electronic control device is connected to each of the plurality of sensors by electrical wiring, the timings at which the sensor signals are A / D converted from the plurality of sensors can be synchronized, but the electronic control device And a large number of electric wirings are required between each of the plurality of sensors. Furthermore, when a plurality of sensors and the electronic control device are arranged at positions separated from each other, many long electric wires are required, and the cost of the electric wires increases.

  Therefore, in order to reduce the cost of electrical wiring, a plurality of signal processing devices that A / D convert sensor signals from a plurality of sensors are used to connect a plurality of signal processing devices and an electronic control device with a single communication cable. Thus, a control system in which the electronic control device acquires digital data through serial communication with a plurality of signal processing devices is conceivable.

  In the control system, when the signal processing device receives a request signal for requesting digital data from the electronic control device, the sensor signal is A / D converted into digital data, and the digital data is transmitted to the electronic control device via digital communication. However, a certain period is required to convert the sensor signal into digital data by the A / D converter. For this reason, there is a delay of a certain period from when the signal processing device receives the request signal from the electronic control device to when the digital data is transmitted to the electronic control device.

  In view of the above points, the present invention provides a signal processing device for transmitting digital data to an electronic control device upon receiving a digital data request signal from the electronic control device, and then electronically controlling the digital data after receiving the request signal from the electronic control device. The purpose is to shorten the delay time that occurs before transmission to the apparatus.

In order to achieve the above object, according to the first aspect of the present invention, conversion means for converting an analog sensor signal output from the sensor into digital data to be transmitted to an external device;
A memory for storing digital data converted by the conversion means;
When receiving a request signal from the external device, communication means for transmitting the digital data stored in the memory to the external device;
Based on the timing of receiving the request signal two times before and the timing of receiving the request signal last time, estimation means for estimating the timing of receiving the request signal next time;
Control means for controlling the timing at which the conversion means performs the conversion and stores the digital data in the memory based on the timing estimated by the estimation means.

  According to the present invention, before the communication means receives the request signal from the external device, the conversion means converts the sensor signal into digital data and stores the digital data in the memory. For this reason, it is possible to shorten the delay time that occurs between receiving the request signal from the external device and transmitting the digital data to the external device. In addition, based on the timing of receiving the request signal two times before and the timing of receiving the request signal last time, the timing of receiving the request signal next time is estimated, and the conversion means performs the conversion based on the estimated timing. Since the timing to store the digital data in the memory is controlled, the conversion means can convert the sensor signal into the digital data immediately before receiving the request signal from the external device. Can be sent to an external device.

  For example, the control means can store the digital data in the memory a predetermined period before the timing estimated by the estimation means. In this case, the conversion means converts the sensor signal into the digital data during the predetermined period. And the time required for the digital data to be stored in the memory.

  In addition to the digital sensor signal obtained by A / D conversion of the sensor signal, the digital data transmitted by the signal processing apparatus can be converted into digital data from the result of performing signal processing on the digital sensor signal. .

In the invention according to claim 2, the communication means also receives other request signals transmitted from the external device to other signal processing devices,
The control means calculates an avoidance period avoiding communication between the external device and the other signal processing device based on the other request signal received by the communication means, and avoids the avoidance period. The digital data is stored in the memory at a timing to be controlled.

  According to the present invention, it is possible to obtain highly accurate digital data and transmit the highly accurate digital data to the external device without being adversely affected by the communication between the external device and another signal processing device. .

In the invention according to claim 3, the sensor has a function of outputting a signal indicating that it is an optimal period suitable for the conversion means to convert the sensor signal from the sensor,
The control means controls timing for storing the digital data in the memory in the optimum period based on the signal from the sensor.

  According to the present invention, since the conversion unit performs the conversion and stores the digital data in the memory in the optimum period suitable for the conversion unit to convert the sensor signal from the sensor, the accuracy is higher. Digital data can be obtained and transmitted to an external device.

In the invention according to claim 4, the sensor has a function of performing a self-diagnosis,
The control unit causes the sensor to perform the self-diagnosis during a period in which the communication unit is not communicating with the external device.

  According to the present invention, a highly accurate self-diagnosis can be performed in the sensor without being adversely affected by communication between the communication means and the external device.

It is a figure showing the whole vehicle brake system composition in a 1st embodiment of the present invention. It is a figure which shows the structure of the signal processing apparatus of FIG. The operation of the electronic control device of FIG. 1, the operation of the communication device of the signal processing device, the counter value of the communication cycle estimation unit, the operation of the timing generation unit, the stored contents of the memory, the operation of the A / D converter, and the value of the sensor signal It is a timing chart which shows. It is a flowchart which shows the control processing of the timing generation part of FIG. It is a timing chart which shows the counter value of the operation | movement of the electronic control apparatus of FIG. 1, the operation | movement of a communication apparatus, and a communication period estimation part. It is a timing chart which shows the operation | movement of the electronic controller in a comparative example, the operation | movement of the communication apparatus of a signal processing apparatus, the memory content of a memory, the operation | movement of an A / D converter, and the value of a sensor signal. It is a timing chart which shows the operation | movement of the electronic controller in the modification of 1st Embodiment, the operation | movement of the communication apparatus of a signal processor, the memory content of a memory, the operation | movement of an A / D converter, and the value of a sensor signal. It is a figure which shows the structure of the signal processing apparatus in 2nd Embodiment of this invention. The operation of the electronic control device of the second embodiment of the present invention, the operation of the communication device of the signal processing device, the counter value of the communication cycle estimation unit, the operation of the timing generation unit, the stored contents of the memory, the operation of the A / D converter, It is a timing chart which shows the value of a sensor signal. It is a timing chart which shows the counter value of the action | operation of the electronic control apparatus of 2nd Embodiment of this invention, the action | operation of a communication apparatus, and a communication period estimation part. It is a flowchart which shows the control processing of the timing generation part of FIG. It is a figure which shows the structure of the signal processing apparatus in 3rd Embodiment of this invention. The operation of the electronic control device of the third embodiment of the present invention, the operation of the communication device of the signal processing device, the counter value of the communication cycle estimation unit, the operation of the timing generation unit, the stored contents of the memory, the operation of the A / D converter, 4 is a timing chart showing values of sensor signals, timing signals, and clock signals. It is a flowchart which shows the control processing of the timing generation part of 3rd Embodiment of this invention. It is a figure which shows the structure of the signal processing apparatus of 4th Embodiment of this invention. The operation of the electronic control device of the fourth embodiment of the present invention, the operation of the communication device of the signal processing device, the counter value of the communication cycle estimation unit, the operation of the timing generation unit, the stored contents of the memory, the operation of the A / D converter, 5 is a timing chart showing values of sensor signals and self-diagnosis timing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings in order to simplify the description.

(First embodiment)
1 and 2 show a first embodiment of an in-vehicle brake system according to the present invention. FIG. 1 is a diagram showing an overall configuration of an in-vehicle brake system.

  The in-vehicle brake system 1 in FIG. 1 includes an electronic control device 10 and signal processing devices 20A and 20B.

  The electronic control device 10 is for controlling a wheel brake device, and is connected to the signal processing devices 20 </ b> A and 20 </ b> B via a single communication cable 30. The communication cable 30 is for performing serial communication in digital communication between the electronic control device 10 and the signal processing devices 20A and 20B. The electronic control device 10 controls the brake device for preventing the skidding of the vehicle and the like based on data acquired via the communication cable 30 between the signal processing devices 20A and 20B.

  When the signal processing device 20 </ b> A receives a request signal for requesting digital data from the electronic control device 10, the sensor signal of the yaw rate sensor is A / D converted into digital data, and the digital data is transmitted via the communication cable 30 to the electronic control device. 10 to send. The digital data is data indicating the voltage of the sensor signal.

  FIG. 2 shows a specific configuration of the signal processing device 20A. The signal processing device 20A includes a yaw rate sensor 21a, an A / D converter 22, a memory 23, a communication device 24, a communication cycle estimation unit 25, and a timing generation unit 26.

  The yaw rate sensor 21a is a sensor that detects the yaw rate of the vehicle. The A / D converter 22 is an analog / digital converter that A / D converts the sensor signal output from the yaw rate sensor 21a into digital data. The digital data of this embodiment is digital data indicating the voltage of the sensor signal. The memory 23 is a buffer memory that temporarily holds digital data output from the A / D converter 22. The communication device 24 performs serial communication with the electronic control device 10 via the communication cable 30.

  The communication period estimation unit 25 estimates the timing of receiving the request signal next time based on the counter value of a counter that counts the passage of time. The timing generator 26 controls the timing at which A / D conversion is performed by the A / D converter 22 according to the timing estimated by the communication cycle estimation unit 25. Note that the communication period estimation unit 25 and the timing generation unit 26 are configured by a microcomputer or the like and execute processing to be described later.

  The signal processing device 20B of FIG. 1 includes an acceleration sensor 21b that detects vehicle acceleration instead of the yaw rate sensor 21a, and the configuration other than the acceleration sensor 21b is the same as that of the signal processing device 20A.

  In the present embodiment, the electronic control device 10 constitutes an external device, the A / D converter constitutes a conversion means, and the communication device constitutes a communication means in relation to the constituent elements described in the claims. The communication period estimation unit constitutes an estimation unit, and the timing generation unit constitutes a control unit.

  Next, the operation of this embodiment will be described. First, the electronic control apparatus 10 transmits a request signal to the signal processing apparatuses 20A and 20B via the communication cable 30 in a time division manner. Before receiving the request signal from the electronic control device 10, the signal processing devices 20 </ b> A and 20 </ b> B convert the sensor signal into digital data by the A / D converter 22 and store it in the memory 23. When the signal is received, the digital data is transmitted to the electronic control apparatus 10 via the communication cable 30.

  Hereinafter, details of operations of the electronic control device 10 and the signal processing device 20A will be described with reference to FIG. 3A is a timing chart showing the operation of the electronic control device 10, FIG. 3B is a timing chart showing the operation of the communication device 24 of the signal processing device 20A, and FIG. FIG. 3D is a timing chart showing the counter value of the timing generator 26. FIG. 3E is a timing chart showing the transition of data held in the memory 23, FIG. 3F is a timing chart showing the operation of the A / D converter 22, and FIG. 3G is an output from the yaw rate sensor 21a. It is a timing chart which shows the value of the sensor signal to be performed.

  As illustrated in FIGS. 3A and 3B, the electronic control device 10 transmits a request signal to the communication device 24 of the signal processing device 20 </ b> A multiple times. 3A and 3B show an example in which the electronic control device 10 transmits a request signal to the signal processing device 20A at timings T (N) and T (N + 1).

  At timing T (N), when receiving the Nth request signal, the communication device 24 transmits the digital data (N) stored in the memory 23 to the electronic control device 10 through the communication cable 30 (FIG. 3B). ) Medium data transmission). In addition to this, the communication device 24 outputs the Nth request signal to the communication cycle estimation unit 25 in response to the reception of the Nth request signal.

  The communication cycle estimation unit 25 calculates the estimated reception timing estimated to receive the next request signal, that is, the (N + 1) th request signal, specifically, the counter value indicating the estimated reception timing. As described above, the counter is a counter that counts the passage of time. The timing generator 26 controls the timing at which the A / D converter 22 performs A / D conversion on the sensor signal of the yaw rate sensor 21 a based on the counter value calculated by the communication cycle estimation unit 25. Since the A / D converted digital data is stored in the memory 23, the timing generator 26 controls the timing at which the A / D converter 22 performs A / D conversion and stores the digital data in the memory 23. Will be.

  Hereinafter, the operation of the communication cycle estimation unit 25 and the timing generation unit 26 will be described with reference to FIG. FIG. 4 is a flowchart showing processing of the communication cycle estimation unit 25 and the timing generation unit 26.

  First, in step S100, the counter value of the counter at the estimated reception timing estimated to receive the (N + 1) th request signal is calculated. Hereinafter, the calculated counter value is referred to as a counter value ST (N + 1) of the (N + 1) th estimated reception timing.

  Specifically, the (N + 1) -th estimated reception timing includes the count value C (N) of the counter at the reception timing T (N) at which the N-th request signal is received, and the (N−1) -th request signal. Based on the count value C (N−1) (see FIG. 5) of the counter at the received reception timing T (N−1), the following equation (1) is used.

(N + 1) th estimated reception timing counter value ST (N + 1) = count value C (N) + {count value C (N) −count value C (N−1)} (1)
5A, 5 </ b> B, and 5 </ b> C, the electronic control device 10 transmits a request signal to the signal processing device 20 </ b> A at timings T (N−1) and T (N). An example is shown in which the difference between the counter value of the counter at (N−1) and the counter value of the counter at timing T (N) is {count value C (N) −count value C (N−1)}. ing.

  Next, in step S110, using the counter value ST (N + 1) of the (N + 1) th estimated reception timing, the A / D converter 22 performs a counter value (A / D conversion) on the sensor signal of the yaw rate sensor 21a. Hereinafter, the A / D conversion counter value is calculated.

  Specifically, the A / D conversion counter value is a time obtained by subtracting the processing time from the timing ST (N + 1) (= ST (N + 1) −processing time). The processing time is the time required for the A / D converter 22 to A / D convert the sensor signal of the yaw rate sensor 21 a into digital data and store the digital data in the memory 23.

  Next, in step S120, it is determined whether or not the current counter value matches the A / D conversion counter value. If the current counter value does not coincide with the A / D conversion timing, the determination in step S120 is NO and the process returns to step S120. Therefore, the determination in step S120 is repeated until it is determined that the current counter value matches the A / D conversion timing.

  Thereafter, when the current counter value coincides with the A / D conversion timing, the determination in step S120 becomes YES, and the process proceeds to step S130. In step S130, the A / D converter 22 is instructed to A / D convert the sensor signal of the yaw rate sensor 21a into digital data. Accordingly, the A / D converter 22 A / D converts the sensor signal of the yaw rate sensor 21a into digital data (N + 1) (see FIG. 3F). That is, the timing at which the sensor signal is taken into the A / D converter 22 is controlled, and the sensor signal is A / D converted by the A / D converter 22 at the timing when the current counter value coincides with the A / D conversion timing. It will be. Accordingly, digital data (N + 1) acquired by the A / D converter 22 is stored in the memory 23 (see FIG. 3E).

  Next, when the communication device 24 receives the (N + 1) th request signal from the electronic control device 10 through the communication cable 30 at timing T (N + 1), the communication device 24 communicates the digital data (N + 1) stored in the memory 23. It transmits to the electronic control apparatus 10 through the cable 30 (refer FIG.3 (b)). Thereafter, the electronic control unit 10 receives the digital data (N + 1) (denoted as data reception in FIG. 3A).

  In addition, the communication device 24 outputs the (N + 1) th request signal to the communication cycle estimation unit 25. Thereby, the communication cycle estimation unit 25 and the timing generation unit 26 perform the same operation as described above.

  That is, in step S100, the counter value ST (N + 2) {= C (N + 1) + (C (N + 1) −C (N))} of the (N + 2) th estimated reception timing is calculated. Next, in step S110, the A / D conversion counter value {= (ST (N + 2) −processing time)} is calculated using the counter value ST (N + 2) of the (N + 2) th estimated reception timing, and step S120. In step (1), it is determined whether or not the current counter value matches the A / D conversion counter value. When the current counter value matches the A / D conversion counter value, in step S130, the A / D converter 22 is instructed to A / D convert the sensor signal of the yaw rate sensor 21a into digital data (N + 2). Digital data (N + 2) acquired by / D conversion is stored in the memory 23.

  Next, when the communication device 24 receives the (N + 2) -th request signal from the electronic control device 10 through the communication cable 30, the digital data (N + 2) stored in the memory 23 is transmitted through the communication cable 30 to the electronic control device 10. Send to.

  Further, after receiving the digital data (N) from the signal processing device 20A, the electronic control device 10 transmits a request signal to the signal processing device 20B. Each time the signal processing device 20B receives a request signal from the electronic control device 10, the signal processing device 20B transmits digital data in the same manner as the signal processing device 20A. And the electronic control apparatus 10 controls a brake device according to the digital data from signal processing apparatus 20A, 20B.

  According to the present embodiment described above, when the communication device 24 of the signal processing device 20A (20B) receives the request signal from the electronic control device 10 through the communication cable 30, the communication cycle estimation unit 25 next requests the request signal. The counter value of the estimated reception timing estimated to be received is calculated. The timing generator 26 subtracts the processing time from the counter value of the next estimated reception timing, calculates the A / D conversion counter value of the timing at which the A / D converter 22 A / D converts the sensor signal, When the counter value matches the A / D conversion counter value, the A / D converter 22 is instructed to A / D convert the sensor signal of the yaw rate sensor 21a (acceleration sensor 21b) into digital data. Accordingly, digital data acquired by the A / D converter 22 is stored in the memory 23. When receiving the next request signal from the electronic control device 10 through the communication cable 30, the communication device 24 transmits the digital data stored in the memory 23 to the electronic control device 10 through the communication cable 30. Therefore, when the communication device 24 receives the request signal from the electronic control device 10, digital data can be transmitted to the electronic control device 10 without causing a long delay time.

  Next, the superiority of the above-described embodiment will be described using a comparative example. 6A to 6E show timing charts in the comparative example. 6A is a timing chart showing the operation of the electronic control device 10, FIG. 6B is a timing chart showing the operation of the signal processing device, and FIG. 6C shows the transition of data held in the memory 23. FIG. 6D is a timing chart showing the operation of the A / D converter 22, and FIG. 6E is a timing chart showing the value of the sensor signal.

  In this comparative example, as shown in FIGS. 6C and 6D, at timing T (N), the A / D converter 22 converts the sensor signal (denoted as sensor signal (2) in the figure) into digital data ( A / D conversion is performed on the digital data (2) in the figure, and this digital data is stored in the memory 23. At the next timing T (N + 1), the digital data stored in the memory 23 is converted into the electronic control unit 10. (See FIGS. 6A to 6C).

  In such a case, it takes a long time between the A / D converter 22 A / D converting the sensor signal into digital data and transmitting the digital data to the electronic control device 10. For this reason, the digital data does not indicate the value of the sensor signal immediately before receiving the request signal, but is data indicating the sensor signal at the time of going back in the past. For this reason, the accuracy of the digital data is low.

  In contrast, in the present embodiment, as described above, the A / D conversion counter value at the timing at which the A / D converter 22 performs A / D conversion on the sensor signal is changed from the counter value at the next estimated reception timing to the processing time. Subtract to calculate. Therefore, digital data indicating the value of the sensor signal immediately before receiving the request signal, that is, the latest digital data can be acquired by A / D conversion of the A / D converter 22. For this reason, the signal processing device 20 </ b> A (20 </ b> B) can acquire highly accurate digital data and transmit it to the electronic control device 10.

  In addition, each of the signal processing devices 20A and 20B acquires digital data by A / D conversion immediately before receiving the request signal. Therefore, the timing at which the electronic control device 10 transmits the request signal to the signal processing device 20A and the timing at which the electronic control device 10 transmits the request signal to the signal processing device 20B are made closer so that the signal processing devices 20A and 20B The timing for A / D conversion can be made close to each other. And the electronic control apparatus 10 controls a brake device based on each digital data acquired by such A / D conversion. For this reason, the brake device can be controlled with high accuracy.

  In order to transmit digital data indicating the value of the sensor signal immediately before the communication device 24 receives the request signal from the electronic control device 10, A / D conversion by the A / D converter 22 is performed. It is conceivable that the digital data obtained by A / D conversion immediately before receiving the request signal is transmitted to the electronic control device 10 by repeatedly performing the operation. However, in this case, if A / D conversion is repeatedly performed, the power consumption of the A / D converter 22 increases.

  On the other hand, in the present embodiment, the timing generator 26, based on the A / D conversion counter value of the timing at which the A / D converter 22 A / D converts the sensor signal, as described above. The converter 22 is instructed to perform A / D conversion of the sensor signal. For this reason, when the signal processing device 20A (20B) receives the request signal once from the electronic control device 10, the signal processing device 20A (20B) performs A / D conversion once in response to this one reception. Therefore, an increase in power consumption of the A / D converter 22 can be suppressed.

  In the first embodiment, the example in which the processing in which the electronic control device 10 transmits the request signal to the signal processing device 20A and the processing in which the electronic control device 10 transmits the request signal to the signal processing device 20B is performed in a time-sharing manner has been described. However, instead of this, the electronic control device 10 may simultaneously transmit request signals to the signal processing devices 20A and 20B.

  7A to 7C illustrate an example in which the electronic control device 10 transmits request signals to the signal processing devices 20A and 20B at the timings T (N) and T (N + 1) at the same time. FIGS. 7A to 7G are timing charts corresponding to FIGS. 3A to 3G.

(Second Embodiment)
In this embodiment, the sensor signal of the yaw rate sensor 21a is A / D converted by the A / D converter 22 of the signal processing device 20A during a period avoiding the communication period between the electronic control device 10 and the signal processing device 20B. Is.

  FIG. 8 shows the configuration of the signal processing device 20A in the present embodiment. 8, the same reference numerals as those in FIG. 2 denote the same components. The communication device 24 of the signal processing device 20A, in addition to a request signal for requesting digital data from the communication device 24 itself, a request signal for requesting digital data from the signal processing device 20B (hereinafter referred to as other request signal). And request signals are output to the communication cycle estimation unit 25.

  The operation of the communication period estimation unit 25 and the timing generation unit 26 in the present embodiment will be described with reference to FIGS. 9A to 9G are timing charts corresponding to FIGS. 3A to 3G. FIGS. 10A to 10C are timing charts showing changes in counter values of the electronic control device 10, the communication device 24, and the communication cycle estimation unit 25 corresponding to FIGS. 5A to 5C.

  As shown in FIGS. 10A to 10C, the electronic control unit 10 transmits a signal at timing Ta (N) before transmitting the Nth request signal to the signal processing device 20A at timing T (N). The Nth other request signal is transmitted to the processing device 20B. As shown in FIGS. 9A to 9C, the electronic control unit 10 transmits the (N + 1) th request signal to the signal processing device 20A at the timing T (N + 1) at the timing Ta (N + 1). The (N + 1) th other request signal is transmitted to the signal processing device 20B.

  The communication cycle estimation unit 25 and the timing generation unit 26 execute the processing according to the flowchart shown in FIG.

  First, in step S100, as in the first embodiment, the (N + 1) th estimated reception timing counter value ST (N + 1) is calculated. In the next step S110, the (N + 1) th estimated reception timing counter value ST is calculated. Using (N + 1), an A / D conversion counter value at a timing at which the A / D converter 22 performs A / D conversion of the sensor signal is calculated. The A / D conversion counter value in this embodiment is a time obtained by subtracting the processing time and the avoidance time from the timing ST (N + 1) (= ST (N + 1) −processing time−evasion time). The avoidance time is an estimated reception timing T (N + 1) estimated to receive the request signal at the (N + 1) th time and an estimated reception timing Ta (N + 1) estimated to receive another request signal at the (N + 1) th time. It is a period between. The avoidance time is obtained by subtracting the counter value of the communication cycle estimation unit 25 at the reception timing Ta (N) from the counter value of the communication cycle estimation unit 25 at the reception timing T (N) (see FIGS. 10A to 10C). Is calculated by The processing time is the same as the processing time described in the first embodiment.

  In the next step S120, it is determined whether or not the current counter value matches the A / D conversion counter value. When the current counter value matches the A / D conversion counter value, the determination in step S120 is YES, and in step S130, the A / D converter 22 is instructed to send the sensor signal of the yaw rate sensor 21a to the A / D. Convert it.

  Further, the signal processing device 20B operates in the same manner as in the first embodiment. For this reason, when the signal processing device 20B receives the (N + 1) th other request signal from the electronic control device 10 at the timing Ta (N + 1), the digital data acquired by the A / D conversion immediately before the reception is received. It transmits to the electronic control unit 10.

  In the present embodiment described above, A / D conversion is performed on the digital data of the sensor signal of the yaw rate sensor 21a immediately before the communication device 24 receives the request signal from the electronic control device 10, as in the first embodiment. The digital data is stored in the memory 23. For this reason, when the communication device 24 receives the request signal from the electronic control device 10, it is possible to transmit highly accurate digital data to the electronic control device 10 without causing a long delay time.

  Further, in the present embodiment, the electronic control unit 10 transmits the (N + 1) -th request signal to the signal processing device 20A at the timing T (N + 1), at the timing Ta (N + 1), to the signal processing device 20B ( N + 1) The other request signal is transmitted.

  Therefore, in this embodiment, the A / D conversion counter value is calculated as a time obtained by subtracting the processing time and the avoidance time from the timing ST (N + 1) (= ST (N + 1) −processing time−evasion time). The avoidance time is a period between the estimated reception timing Ta (N + 1) and the estimated reception timing T (N + 1). Therefore, the sensor signal of the yaw rate sensor 21a can be A / D converted by the A / D converter 22 of the signal processing device 20A at a timing that avoids the communication period between the electronic control device 10 and the signal processing device 20B. it can.

  Here, if communication is performed between the electronic control device 10 and the signal processing device 20B, electromagnetic noise may be generated and the digital data obtained from the A / D converter 22 may be adversely affected.

  In contrast, in the present embodiment, as described above, the yaw rate sensor 21a is detected by the A / D converter 22 of the signal processing device 20A at a timing that avoids the communication period between the electronic control device 10 and the signal processing device 20B. A / D conversion is performed on the sensor signal. Therefore, highly accurate digital data can be acquired from the A / D converter 22 and transmitted to the electronic control device 10.

  Here, in the example of FIG. 9A, the electronic control device 10 transmits another request signal to the signal processing device 20B at the timing Ta (N + 1). In this case, as shown in FIG. 9F, the signal processing device 20A performs A / D conversion of the sensor signal by the A / D converter 22 immediately before the timing Ta (N + 1). In addition, the signal processing device 20B performs A / D conversion on the sensor signal immediately before the timing Ta (N + 1) as described above. Therefore, the timing at which the signal processing device 20A performs A / D conversion and the timing at which the signal processing device 20B performs A / D conversion can be synchronized. And since the electronic control apparatus 10 controls a brake device using the digital data obtained by such A / D conversion, it can control a brake device with high precision.

(Third embodiment)
In the present embodiment, when it is determined that it is the optimum timing according to the operating state of the yaw rate sensor 21a, the A / D converter 22 is instructed to A / D convert the sensor signal of the yaw rate sensor 21a.

  FIG. 12 shows the configuration of the signal processing device 20A in the present embodiment. 12, the same reference numerals as those in FIG. 2 denote the same components. FIGS. 13A to 13F are timing charts similar to FIGS. 3A to 3F.

  The yaw rate sensor 21a is based on a sensor element that detects a yaw rate, an oscillator that outputs a clock signal (see FIG. 13H) that alternately repeats a high level period and a low level period, and a clock signal from the oscillator. And a control circuit that outputs a sensor signal obtained by performing signal processing such as voltage amplification on the output signal of the sensor element to the A / D converter 22.

  Here, the rising time and the falling time of the clock signal include a signal of a high frequency component, so that electromagnetic noise is likely to occur. For this reason, if the sensor signal is A / D converted by the A / D converter 22 at the rising timing and falling timing of the clock signal, the A / D conversion may be adversely affected by electromagnetic noise.

  Therefore, in the present embodiment, when the sensor signal is A / D converted by the A / D converter 22, the time period excluding the rising time and the falling time of the clock signal is set as the optimum period. The rise time and the fall time are set as a prohibition period in which the A / D converter 22 prohibits the A / D conversion of the sensor signal. Then, the control circuit outputs a timing signal (see FIG. 13G) indicating whether the present time is the optimum period or the prohibition period to the timing generator 26.

  When receiving the request signal from the communication device 24, the timing generator 26 performs control processing on the A / D converter 22 according to the flowchart of FIG.

  The flowchart of FIG. 14 is obtained by adding step S125 to step S120 and step S130 in FIG.

  When the timing generation unit 26 determines that the current counter value coincides with the A / D conversion timing in step S120, as in the first embodiment, the timing generation unit 26 determines that the control circuit of the yaw rate sensor 21a in step S125. Based on the output timing signal, it is determined whether or not the present time is the optimum period. If the present time is not the optimum period, that is, the prohibition period, NO is determined and the determination in step S125 is repeated. Thereafter, if it is determined that the current period is the optimum period, YES is determined in step S125, and in step S130, the A / D converter 22 is instructed to A / D convert the sensor signal of the yaw rate sensor 21a.

  According to the present embodiment described above, the sensor signal of the yaw rate sensor 21a is converted into digital data immediately before the communication device 24 receives the request signal from the electronic control device 10, as in the first embodiment. The digital data is stored in the memory 23 after conversion. For this reason, when the communication device 24 receives the request signal from the electronic control device 10, it is possible to transmit highly accurate digital data to the electronic control device 10 without causing a long delay time.

  In addition to this, in the present embodiment, when the timing generation unit 26 determines that the current counter value coincides with the A / D conversion timing, the A / D converter 22 currently A / D converts the sensor signal. Is determined to be the optimal period. When it is determined that the current period is the optimum period, the A / D converter 22 performs A / D conversion on the sensor signal to acquire digital data. That is, the sensor signal can be A / D converted in the optimum period immediately after the timing when it is determined that the current counter value coincides with the A / D conversion timing. Therefore, more accurate digital data can be acquired. Accordingly, highly accurate digital data can be transmitted to the electronic control device 10.

(Fourth embodiment)
In the present embodiment, a function for performing self-diagnosis processing of the yaw rate sensor 21a is added to the signal processing device 20A of the first embodiment.

  FIG. 15 shows the configuration of the signal processing device 20A. 15, the same reference numerals as those in FIG. 2 denote the same components.

  As shown in FIG. 15, the yaw rate sensor 21 a of this embodiment includes a sensor element 40 that detects the yaw rate and a self-diagnosis circuit 41 that diagnoses the sensor element 40. As will be described later, the timing generator 26 performs processing for instructing the yaw rate sensor 21a to perform self-diagnosis, in addition to the command processing for the A / D converter 22.

  Next, self-diagnosis of the yaw rate sensor 21a will be described. FIGS. 16A to 16G are timing charts similar to those in FIGS. 3A to 3G, and FIG. 16H is a timing chart illustrating the timing for performing the self-diagnosis of the yaw rate sensor 21a. .

  First, when the A / D converter 22 does not A / D convert the sensor signal of the yaw rate sensor 21a, the sensor signal of the yaw rate sensor 21a is not used. For this reason, during the period from the A / D conversion by the A / D converter 22 to the Nth time until the A / D converter 22 performs the (N + 1) th A / D conversion, the self-rate of the yaw rate sensor 21a. Diagnosis can be performed.

  However, when the signal processing device 20A performs communication with the electronic control device 10, electromagnetic noise or the like may occur, which may adversely affect the self-diagnosis of the yaw rate sensor 21a.

  Therefore, the timing generator 26 instructs the self-diagnosis circuit 41 of the yaw rate sensor 21a to perform self-diagnosis during a period avoiding the communication period between the signal processing device 20A and the electronic control device 10.

  In FIGS. 16B and 16E, when the communication device 24 transmits the digital data (N) stored in the memory 23 to the electronic control device 10 at the timing Tb (N), the communication device 24 receives the digital data (N ) Is transmitted to the timing generation unit 26 through the communication period estimation unit 25.

  When receiving the transmitted signal from the communication device 24, the timing generator 26 instructs the self-diagnosis circuit 41 of the yaw rate sensor 21a to perform self-diagnosis. When receiving a command from the timing generator 26, the self-diagnosis circuit 41 performs a diagnosis as to whether or not a failure has occurred in the sensor element 40.

  Thereafter, when the diagnosis of the sensor element 40 by the self-diagnosis circuit 41 is completed, the diagnosis result (internal failure diagnosis result) of the self-diagnosis circuit 41 is output to the memory 23 through the A / D converter 22. As a result, the diagnosis result of the sensor element 40 is stored in the memory 23.

  Here, when the previous diagnosis result is stored in the memory 23 in advance, the diagnosis result stored in the memory 23 is updated with the current diagnosis result output from the self-diagnosis circuit 41. .

  Thereafter, when the communication device 24 receives the request signal from the electronic control device 10 at the timing T (N + 1), the digital data (N + 1) stored in the memory 23 and the diagnosis result are transmitted to the electronic control device 10 through the communication cable 30. Output.

  Further, when the self-diagnosis circuit 41 performs self-diagnosis on the sensor element 40, the value of the sensor signal becomes unstable. For this reason, after the self-diagnosis of the sensor element 40 is performed, until the A / D converter 22 performs the next A / D conversion (that is, (N + 1) th A / D conversion), the sensor signal A signal stabilization wait time is provided to stabilize the signal.

  Such a self-diagnosis of the sensor element 40 is performed every time the communication device 24 transmits digital data to the electronic control device 10. The self-diagnosis result of the sensor element 40 is transmitted to the electronic control device 10 by the communication device 24 every time the communication device 24 receives a request signal from the electronic control device 10.

  In the present embodiment described above, the same effects as those in the first embodiment described above can be obtained. In addition to this, in the present embodiment, the yaw rate sensor 21a is used during a period between the A / D conversion by the A / D converter 22 and the A / D conversion by the A / D converter 22 next time. Carry out self-diagnosis. For this reason, the signal processing device 20A can repeatedly perform the self-diagnosis of the yaw rate sensor 21a by repeatedly transmitting the digital data in response to the request signal from the electronic control device 10. Thereby, the self-diagnosis capability of the yaw rate sensor 21a can be improved.

  In the present embodiment, the self-diagnosis of the yaw rate sensor 21a is performed in a period avoiding the communication period between the signal processing device 20A and the electronic control device 10 as described above. For this reason, a highly accurate self-diagnosis can be obtained in the yaw rate sensor 21a.

  In the first to fourth embodiments, the example in which the signal processing device 20A (20B) transmits the digital sensor signal as digital data to the electronic control device 10 has been described. However, the processing is performed by performing signal processing on the digital sensor signal. The result may be digital data.

  Further, the one described in the third embodiment may be applied to the second embodiment, and the one described in the fourth embodiment may be applied to the second and third embodiments.

  In the first to fourth embodiments, the example in which the signal processing device according to the present invention is applied to an in-vehicle brake system has been described. You may apply to.

DESCRIPTION OF SYMBOLS 1 In-vehicle brake system 10 Electronic control unit 20A Signal processing unit 20B Signal processing unit 21a Yaw rate sensor,
21b Acceleration sensor 22 A / D converter 23 Memory 24 Communication device 25 Communication cycle estimation unit 26 Timing generation unit 40 Sensor element 41 Self-diagnosis circuit

Claims (4)

Conversion means for converting an analog sensor signal output from the sensor into digital data to be transmitted to an external device;
A memory for storing digital data converted by the conversion means;
When receiving a request signal from the external device, communication means for transmitting the digital data stored in the memory to the external device;
Based on the timing of receiving the request signal two times before and the timing of receiving the request signal last time, estimation means for estimating the timing of receiving the request signal next time;
A signal processing apparatus comprising: control means for controlling the timing at which the conversion means performs the conversion and stores the digital data in the memory based on the timing estimated by the estimation means. The communication means is adapted to receive other request signals transmitted from the external device to other signal processing devices,
The control means calculates an avoidance period avoiding communication between the external device and the other signal processing device based on the other request signal received by the communication means, and avoids the avoidance period. The signal processing apparatus according to claim 1, wherein timing for storing the digital data in the memory is controlled. The sensor has a function of outputting a signal indicating that it is an optimum period suitable for the conversion means to convert the sensor signal from the sensor,
3. The signal processing apparatus according to claim 1, wherein the control unit controls timing of storing the digital data in the memory during the optimum period based on the signal from the sensor. The sensor has a self-diagnosis function,
4. The signal processing according to claim 1, wherein the control unit causes the sensor to perform the self-diagnosis during a period in which the communication unit does not communicate with the external device. apparatus.

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