JP2018018269A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique to obtain latest sensor values from each of a plurality of sensors of which response times are different from each other.SOLUTION: An electronic control device 30 includes a communication unit 36 and a control unit 32. The communication unit transmits a trigger signal to request transmission of a sensor value to a plurality of sensors 12, 14, 22 and 24, and receives sensor values from the plurality of sensors. The control unit 32 carries out prescribed control on the basis of sensor values received from the sensors by the communication unit. The communication unit transmits a trigger signal to a group of sensors having longer response times at earlier timing than a sensor group having shorter response times regarding a plurality of sensor groups into which a plurality of sensors are divided according to length of response times from transmission of a trigger signal to each of the sensors to reception of sensor values from the sensors.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a technique for transmitting a trigger signal that requests a sensor to transmit a sensor value.

  A technique is known in which an electronic control device acquires a sensor value that is a result of sensing a detection target by each of a plurality of types of sensors, and performs predetermined control based on the acquired sensor value (see, for example, Patent Document 1). .)

  In order for the electronic control unit to acquire a sensor value from the sensor, it is conceivable to transmit a trigger signal requesting to transmit the sensor value to the sensor. The sensor that has received the trigger signal transmits the sensor value to the electronic control unit.

JP 2015-46770 A

  If the sensor type is different, the time required for sensing is different, and further the communication time may be different because the data length of the sensor value is different. As a result, the response time required from when the electronic control device transmits a trigger signal to each of the plurality of sensors until the sensor executes sensing, transmits the sensor value, and is received by the electronic control device is the sensor type. Different for each.

  When a trigger signal is transmitted to a plurality of sensors with different response times at the same timing, the electronic control unit sets a sensor value transmitted from a sensor with a short response time to a sensor value transmitted from a sensor with a long response time. Will be received at an earlier timing.

  Then, when the electronic control device receives sensor values from all the sensors and executes predetermined control, the sensor control unit receives the sensor values from the sensor with a long response time after the sensor values are received from the sensor with a short response time. Wait for completion. As a result, there is a problem that the electronic control device cannot acquire the latest sensor value from a sensor with a short response time.

  One aspect of the present disclosure is to provide a technique for acquiring the latest sensor value from each of a plurality of sensors having different response times.

One aspect of the present disclosure includes a communication unit (36, 66, S406, S410) and a control unit (32, 62).
A communication part transmits the trigger signal which requests | requires transmission of a sensor value to a some sensor (12-16, 22, 24, 72, 82), and receives a sensor value from a some sensor. The control unit performs predetermined control based on sensor values received from the plurality of sensors by the communication unit.

  Further, the communication unit transmits a trigger signal to each of a plurality of sensors, and a plurality of sensor groups in which the plurality of sensors are classified according to the length of response time from reception of sensor values to the sensors. The trigger signal is transmitted to the sensor group having a longer response time than the sensor group having a shorter response time at an earlier timing.

  Thereby, the shift | offset | difference of the timing which completes reception of the sensor value transmitted from a sensor group with a long response time and the timing which completes reception of the sensor value transmitted from a sensor group with a short response time can be reduced as much as possible. Therefore, the control unit can execute predetermined control based on the latest sensor values received from a plurality of sensors having different response times.

  In addition, the code | symbol in the parenthesis described in the claim shows the correspondence with the specific means as described in embodiment mentioned later as one aspect, Comprising: The technical scope of this invention is limited is not.

The block diagram which shows the electronic controller by 1st Embodiment. The time chart which shows a communication process. The flowchart which shows a communication process. The block diagram which shows the electronic control apparatus by the modification of 1st Embodiment. The block diagram which shows the electronic control apparatus by 2nd Embodiment. The time chart which shows a communication process. The block diagram which shows the electronic control apparatus by 3rd Embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Constitution]
The ECU 30 shown in FIG. 1 is mounted on a vehicle and commands the airbag driving device 40 to operate the airbag. ECU is an abbreviation for Electronic Control Unit. The ECU 30 is mainly configured by a known microcomputer including a CPU 32, a semiconductor memory 34 such as a RAM, a ROM, and a flash memory, and a communication circuit 36. Hereinafter, the semiconductor memory is also simply referred to as a memory. The number of microcomputers constituting the ECU 30 may be one or more.

  Various functions of the ECU 30 are realized by the CPU 32 executing a program stored in a non-transitional physical recording medium. In this example, the memory 34 corresponds to a non-transitional tangible recording medium that stores a program. Also, by executing this program, a method corresponding to the program is executed.

  A method for realizing various functions of the ECU 30 is not limited to software, and a part or all of the functions may be realized by using one or a plurality of hardware. For example, when various functions of the ECU 30 are realized by an electronic circuit that is hardware, the electronic circuit may be realized by a digital circuit including a large number of logic circuits, an analog circuit, or a combination thereof.

  The ECU 30 communicates with the seating sensors 12 and 14 and the acceleration sensors 22 and 24 by the SENT method. SENT is an abbreviation for Single Edge Nibble Transmission. Since the SENT system is a variable length communication, the time for one communication varies depending on the data length of communication data. The seating sensors 12 and 14 and the acceleration sensors 22 and 24 constitute a double system so that even if one of them fails, the other functions as a normal sensor.

  The seating sensors 12 and 14 are sensors that detect whether or not an occupant is seated in a seat where the seating sensors 12 and 14 are installed. For example, pressure sensors are used. Since it is assumed that a driver is seated in the driver's seat, the seating sensors 12 and 14 in FIG. 1 are installed, for example, in the passenger seat.

The acceleration sensors 22 and 24 are sensors that detect acceleration applied to the vehicle. The ECU 30 detects an impact applied to the vehicle from the acceleration received from the acceleration sensors 22 and 24.
When the sensor values of the acceleration sensors 22 and 24 indicate that an impact of a predetermined value or more is applied to the vehicle, the ECU 30 instructs the airbag driving device 40 based on the sensor values of the seating sensors 12 and 14 to seat the passenger. Activating the airbag in the seat.

  The seating sensors 12 and 14 constitute a first sensor group 10, and the acceleration sensors 22 and 24 constitute a second sensor group 20. When the seating sensors 12 and 14 and the acceleration sensors 22 and 24 receive a trigger signal that is a request for transmitting a sensor value from the ECU 30, the seating sensors 12 and 14 sense the detection target and transmit the sensor value that is the sensing result to the ECU 30 by the SENT method.

  In FIG. 2, the time required from when the seating sensors 12 and 14 and the acceleration sensors 22 and 24 start sensing until all the sensor value data is acquired and the sensing ends is the sensing time. The time required for the seating sensors 12 and 14 and the acceleration sensors 22 and 24 to start the sensor value transmission to the ECU 30 until the ECU 30 finishes receiving the sensor value is the communication time.

  In FIG. 2, a response time is defined by adding a margin time in consideration of variations in the sensing time and the communication time to the sensing time and the communication time. The response time of the seating sensors 12 and 14 that are the first sensor group 10 is longer than the response time of the acceleration sensors 22 and 24 that are the second sensor group 20.

  The ECU 30 triggers each of the first sensor group 10 and the second sensor group 20 so that the timings of completing reception of sensor values from the first sensor group 10 and the second sensor group 20 coincide. Signal transmission timing is stored in the memory 34 in advance. Hereinafter, the timing for transmitting the trigger signal is also referred to as trigger timing.

  For example, the ECU 30 stores, in the memory 34, a trigger standby time for waiting for transmission of a trigger signal from the start of the control cycle to the trigger timing as a parameter for determining the trigger timing. In the first embodiment, the trigger standby time is assumed to be a constant control cycle of the ECU 30 and does not change, and is a difference between the control cycle and the response times of the first sensor group 10 and the second sensor group 20. Is set based on.

  Since the response time of the first sensor group 10 is longer than the response time of the second sensor group 20, the trigger standby time of the first sensor group 10 is shorter than the trigger standby time of the second sensor group 20. Therefore, the trigger timing of the first sensor group 10 is earlier than the trigger timing of the second sensor group 20.

  Since the response time between the first sensor group 10 and the second sensor group 20 is fixed and the control cycle of the ECU 30 is constant, the trigger timing between the first sensor group 10 and the second sensor group 20 is fixed. is there.

The ECU 30 executes predetermined control processing in the next control cycle based on sensor values received from the first sensor group 10 and the second sensor group 20 in the current control cycle.
[1-2. processing]
The communication process executed by the ECU 30 will be described based on the flowchart of FIG. The communication process of FIG. 3 is always executed.

  In S <b> 400, the CPU 32 acquires the trigger standby times of the first sensor group 10 and the second sensor group 20 from the memory 34. In S402, the CPU 32 acquires the elapsed time from the start of the control cycle from the timer. The timer is cleared at every control cycle start timing, and measures the elapsed time from the start of the control cycle.

  When the determination in S <b> 404 is No and the elapsed time has not reached the trigger standby time of the first sensor group 10, the CPU 32 determines that the current timing is not the trigger timing of the first sensor group 10. In this case, the CPU 32 moves the process to S408.

  If the determination in S404 is Yes and the elapsed time has reached the trigger standby time of the first sensor group 10, the CPU 32 determines that the current timing is the trigger timing of the first sensor group 10. In this case, in S <b> 406, the CPU 32 causes the first sensor group 10 to transmit a trigger signal that instructs the communication circuit 36 to request transmission of the sensor value.

  When the determination in S <b> 408 is No and the elapsed time has not reached the trigger standby time of the second sensor group 20, the CPU 32 determines that the current timing is not the trigger timing of the second sensor group 20. In this case, the CPU 32 ends this process.

  If the determination in S <b> 408 is Yes and the elapsed time has reached the trigger standby time of the second sensor group 20, the CPU 32 determines that the current timing is the trigger timing of the second sensor group 20. In this case, in S <b> 410, the CPU 32 transmits a trigger signal that instructs the communication circuit 36 to request transmission of the sensor value to the second sensor group 20.

[1-3. Modified example]
In the modification of the first embodiment shown in FIG. 4, an example is shown in which airbags installed in the left and right seats 6, 8 in addition to the driver seat 2 and the passenger seat 4 are operated. Since it is assumed that a driver is seated in the driver's seat 2, no seating sensor is installed. In the modification shown in FIG. 4, the seating sensor does not constitute a double system, and one seating sensor 12, 14, and 16 is installed in each of the passenger seat 4 and the left and right seats 6, 8. .

  Two seating sensors may be installed in each of the passenger seat 4 and the rear left and right seats 6 and 8 to form a duplex system. The three seating sensors 12, 14, 16 constitute a first sensor group. The acceleration sensors 22 and 24, which are the second sensor group 20, constitute a double system as in FIG.

The communication process executed by the ECU 30 is the same as that in the flowchart of FIG. 3 except that the number of seating sensors 12, 14, and 16 constituting the first sensor group is three.
[1-4. effect]
In the first embodiment described above, the following effects can be obtained.

  For the first sensor group whose response time is longer than that of the second sensor group, the trigger timing for requesting transmission of sensor values is made earlier than that of the second sensor group. Thereby, the shift | offset | difference of the timing which ECU30 completes reception of the sensor value transmitted from the 1st sensor group and the 2nd sensor group can be reduced. As a result, the ECU 30 can execute air bag drive control as predetermined control based on the latest sensor values received from the plurality of sensor groups.

In the first embodiment described above, the ECU 30 corresponds to the electronic control device, the CPU 32 corresponds to the control unit, and the communication circuit 36 corresponds to the communication unit.
S406 and S410 correspond to processing as a communication unit.

[2. Second Embodiment]
[2-1. Difference from the first embodiment]
The second embodiment shown in FIG. 5 is different from the first embodiment in that the control object of the ECU 60 is an injector 52 mounted on the engine 50 and that the control cycle of the ECU 60 changes according to the change in the engine speed. Is different.

  The ECU 60 is configured around a known microcomputer including a CPU 62, a semiconductor memory 64 such as a RAM, a ROM, and a flash memory, and a communication circuit 66. The number of microcomputers constituting the ECU 60 may be one or more. Since the configuration of the ECU 60 is substantially the same as that of the ECU 30 of the first embodiment, further description is omitted.

  The ECU 60 controls the injection amount and injection timing of the injector 52 mounted on the engine 50. The ECU 60 communicates with the atmospheric temperature sensor 72 that is the first sensor group 70 and the air-fuel ratio sensor 82 that is the second sensor group 80 by the SENT method.

  The response time of the atmospheric temperature sensor 72 is longer than the response time of the air-fuel ratio sensor 82. Therefore, the trigger timing for the atmospheric temperature sensor 72 is earlier than the trigger timing for the air-fuel ratio sensor 82 in order for the ECU 60 to receive the sensor values from the atmospheric temperature sensor 72 and the air-fuel ratio sensor 82 to coincide with the completion timing. Is set to be

  The ECU 60 receives a pulse signal from the rotation speed sensor 90 every time the engine 50 rotates by a predetermined angle. The ECU 60 calculates the engine rotational speed based on the number of pulse signals received from the rotational speed sensor 90 per unit time. The ECU 60 determines the injection amount and the injection timing of the injector 52 in synchronization with the rotation angle of the engine 50 based on the atmospheric temperature and the air-fuel ratio which are sensor values received from the atmospheric temperature sensor 72 and the air-fuel ratio sensor 82. Control.

  The control cycle in which the ECU 60 controls the injection amount and the injection timing of the injector 52 in synchronization with the rotation angle of the engine 50 becomes shorter as the rotation speed of the engine 50 increases, and becomes longer as the rotation speed of the engine 50 decreases.

  On the other hand, the response times of the atmospheric temperature sensor 72 and the air-fuel ratio sensor 82 are constant regardless of the engine speed. Therefore, the ECU 60 receives the sensor values from the atmospheric temperature sensor 72 and the air-fuel ratio sensor 82, and matches the timing of completing the reception with the atmospheric temperature sensor 72 and the air-fuel ratio sensor 82 represented by the trigger standby time. Is set according to the engine speed.

  For example, as shown in FIG. 6, when the engine speed increases, the ECU 60 advances the trigger timing for the atmospheric temperature sensor 72 and the air-fuel ratio sensor 82. In contrast, when the engine speed decreases, the ECU 60 delays the trigger timing for the atmospheric temperature sensor 72 and the air-fuel ratio sensor 82.

[2-2. effect]
In the second embodiment described above, the following effects can be obtained in addition to the effects described in the first embodiment.

  Since the trigger timing is set for each sensor group in accordance with the change in the control cycle of the ECU 60, even if the control cycle changes, it is possible to reduce a deviation in timing for receiving sensor values from a plurality of sensor groups and completing reception. .

In the second embodiment, the ECU 60 corresponds to the electronic control device, the CPU 62 corresponds to the control unit, and the communication circuit 66 corresponds to the communication unit.
[3. Third Embodiment]
[3-1. Difference from the first embodiment]
In the third embodiment shown in FIG. 7, the ECU 100 includes a plurality of timers 102 corresponding to the plurality of sensor groups, and the timer 102 generates a trigger signal to be transmitted from the communication circuit 36 to each of the sensor groups. Different from one embodiment. The same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description is referred to.

  In the timer 102 corresponding to each sensor group, for example, a trigger standby time corresponding to the sensor group is set for each start timing of the control cycle of the ECU 100. Each timer 102 generates a trigger signal to be transmitted from the communication circuit 36 to each of the sensor groups at the trigger timing.

  If the control cycle of the ECU 100 is constant as in the first embodiment, a trigger standby time is set in the timer 102 by hardware at each start timing of the control cycle. On the other hand, when the control cycle of the ECU 100 changes as in the second embodiment, the CPU 32 sets the trigger standby time corresponding to the changing control cycle in the timer 102 at each start timing of the control cycle.

[3-2. effect]
Since the timer 102 generates a trigger signal to be transmitted to each sensor group, the CPU 32 does not need to generate a trigger signal to be transmitted to each sensor group. Thereby, the processing load of the CPU 32 can be reduced.

In the third embodiment, the ECU 100 corresponds to the electronic control device, and the timer 102 corresponds to the timer.
[4. Other Embodiments]
(1) The number of sensors constituting sensor groups with different trigger timings is not limited to one or two, but may be three or more.

  (2) As long as a trigger signal is transmitted from the ECU to the sensor and the ECU can receive the sensor value from the sensor, the communication between the ECU and the sensor is not limited to the SENT method, and any communication method may be used.

  (3) In the above embodiment, the ECUs 30, 60, 100 mounted on the vehicle as the electronic control device have been described. In addition to this, as long as the electronic control device transmits a trigger signal to a sensor group having a longer response time than a sensor group having a shorter response time for a plurality of sensor groups having different trigger timings, any An electronic control device may be applied to the technical field.

  (4) A plurality of functions of one constituent element in the above embodiment may be realized by a plurality of constituent elements, or a single function of one constituent element may be realized by a plurality of constituent elements. In addition, a plurality of functions possessed by a plurality of constituent elements may be realized by one constituent element, or a single function realized by a plurality of constituent elements may be realized by one constituent element. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified only by the wording described in the claims are embodiments of the present invention.

  (5) In addition to the ECUs 30, 60, 100 described above, an electronic control system having the ECU as a constituent element, an electronic control program for causing a computer to function as the ECU, a recording medium storing the electronic control program, and an electronic control method The present invention can also be realized in various forms.

30, 60, 100: ECU (electronic control unit), 32, 62: CPU (control unit), 36, 66: Communication circuit (communication unit), 102: Timer

Claims (4)

A communication unit (36) configured to transmit a trigger signal requesting transmission of sensor values to a plurality of sensors (12 to 16, 22, 24, 72, 82) and to receive the sensor values from the plurality of sensors. 66, S406, S410),
A control unit (32, 62, S400 to S404, S408) configured to perform predetermined control based on the sensor value received by the communication unit from the plurality of sensors;
With
The communication unit is configured to classify the plurality of sensors according to a response time length from when the trigger signal is transmitted to each of the plurality of sensors until the sensor value is received from the sensor. For a plurality of sensor groups (10, 20, 70, 80), the trigger signal is transmitted to the sensor group having a longer response time than the sensor group having a shorter response time at an earlier timing.
Electronic control device (30, 60, 100). The electronic control device according to claim 1.
When the control period by the control unit (32) is constant, the communication unit (36) transmits the trigger signal at a fixed timing set for each of the sensor groups.
Electronic control device. The electronic control device according to claim 1.
When the control cycle by the control unit (62) changes, the control unit is configured so that the communication unit is connected to each of the sensor groups according to the length of the control cycle and the length of the response time of the sensor group. Set the trigger signal transmission timing,
Electronic control device. In the electronic control unit according to any one of claims 1 to 3,
Further comprising a timer (102) configured to generate the trigger signal at a timing to transmit the trigger signal;
Electronic control device (100).