Information processing apparatus

Abstract

An information processing apparatus suppresses erroneous detection that occurs when a power supply voltage of a sensor is reduced. A predetermined physical quantity to be detected by a first sensor element is calculated on the basis of the period of a pulse output by the first sensor element, and when a power supply voltage supplied to the first sensor element is equal to or less than a predetermined voltage, the physical quantity is regarded as a predetermined value regardless of the output of the first sensor element. At this time, the predetermined voltage is a value obtained by adding the minimum drive voltage of the first sensor element and the maximum value of the pulse voltage output by the first sensor element.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to sensor technology. BACKGROUND

[0002] There is a technology for improving the reliability of a sensor possessed by an automobile. In relation to this, for example, Patent Literature 1 discloses a device for improving the reliability by prohibiting detection of rotation in a case where mis-detection caused by noise or the like is presumed in a sensor that detects the rotation of a rotating body.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2003-214905

[0006] Patent Literature 2: Japanese Patent Application Publication No. 2015-045354 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] An object of the present disclosure is to suppress mis-detection that occurs when the power supply voltage of a sensor is reduced.

[0009] TECHNICAL SOLUTION FOR SOLVING THE PROBLEMS

[0010] One aspect of the present disclosure is an information processing device having a control section that performs processing of calculating a predetermined physical quantity that is a detection target of a first sensor element, based on a period of a pulse output from the first sensor element, and regarding the physical quantity as a predetermined value regardless of an output of the first sensor element when a power supply voltage supplied to the first sensor element is a predetermined voltage or less, wherein the predetermined voltage is a value obtained by adding a minimum drive voltage of the first sensor element to a maximum value of a pulse voltage output from the first sensor element.

[0011] Further, as other aspects, an information processing method performed by the above-described device, a program for causing a computer to execute the information processing method, or a computer-readable storage medium having the program stored therein non-transitorily are exemplified.

[0012] EFFECT OF THE INVENTION

[0013] According to the present disclosure, it is possible to suppress mis-detection that occurs when the power supply voltage of a sensor is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 A diagram showing the structure of a sensor element and an ECU.

[0015] Figure 2A graph for explaining input and output voltages of a sensor element.

[0016] Figure 3 A flowchart of processing performed by an ECU.

[0017] Reference Signs

[0018] 10: sensor element; 20: ECU; 201: arithmetic device; 202: storage device; R: rotating body. DETAILED DESCRIPTION

[0019] An ECU possessed by an automobile is connected to a plurality of vehicle-mounted sensors, and senses a plurality of physical quantities required for the vehicle to travel.

[0020] As a typical example of a vehicle-mounted sensor, there is a sensor that detects the rotation of a rotating body. For example, the rotation of a drive gear, a primary pulley, a secondary pulley, and the like included in a transmission is detected by a sensor, and the ECU calculates the number of revolutions based on a signal output from the sensor, so that the transmission can be appropriately controlled.

[0021] These vehicle-mounted sensors need to be driven with a voltage of a predetermined value or more. However, in a vehicle system, there are many cases where the power supply voltage is reduced, and in such a case, a correct value can not be calculated at times.

[0022] For example, assume a sensor element that outputs a pulse signal with a period corresponding to the number of revolutions of an object. For example, the sensor element outputs one pulse when the object rotates one revolution.

[0023] Here, assume a case where the voltage of the power supply supplied to the sensor element is reduced. When the power supply voltage supplied to the sensor element is reduced, the operation of the element is reset, and the voltage being output from the sensor element at that time is sometimes varied. If the variation in the voltage is confused with a normal pulse, an incorrect number of revolutions is calculated at times, a contradiction occurs in the ECU, and as a result, an error is output.

[0024] The information processing apparatus of the present disclosure solves such a problem.

[0025] The information processing apparatus of one aspect of the present disclosure is characterized by having a control section that performs processing of calculating a predetermined physical quantity that is a detection object of a first sensor element, based on the period of a pulse output from the first sensor element, and regarding the physical quantity as a predetermined value regardless of the output of the first sensor element when the power supply voltage supplied to the first sensor element is a predetermined voltage or less, wherein the predetermined voltage is a value obtained by adding the minimum drive voltage of the first sensor element to the maximum value of the pulse voltage output from the first sensor element.

[0026] The information processing device disclosed herein is typically an ECU (Electric Control Unit) mounted in a vehicle. The information processing device is connected to the first sensor element.

[0027] The first sensor element refers to an element that outputs a predetermined physical quantity (such as vehicle speed or gear rotation) as the object of detection through pulse signals. The control unit of the information processing device is capable of calculating the predetermined physical quantity based on the period of the pulses acquired from the first sensor element.

[0028] The control unit can monitor the power supply voltage supplied to the first sensor element. Furthermore, when the power supply voltage is below a predetermined voltage, the physical quantity is treated as a predetermined value. That is, when the voltage supplied to the first sensor element is insufficient, the output pulse is considered unreliable, and the value that should have been calculated based on the output pulse is treated as a predetermined value (e.g., zero).

[0029] The predetermined voltage refers to the sum of the minimum driving voltage of the first sensor element and the maximum value of the pulse voltage output by the first sensor element (i.e., the output voltage at the High state). If the voltage supplied to the first sensor element is insufficient to reach the sum of the minimum driving voltage and the High state voltage, a pulse with a normal waveform can no longer be output, and the minimum driving voltage cannot be met. Therefore, in this case, the calculated value is set as a fixed value to suppress false alarms.

[0030] The embodiments of this disclosure are described below based on the accompanying drawings. The structures of the following embodiments are illustrative, and this disclosure is not limited to the structures of the embodiments.

[0031] (First Implementation)

[0032] An overview of the system according to the first embodiment will be described. The system of this embodiment is a system that detects the rotation of the rotating body R of the automobile by means of sensor element 10 and calculates its rotation number by means of ECU 20.

[0033] The structure of each device that makes up the system is described.

[0034] First, the constituent elements of vehicle 1 will be explained. Figure 1 The diagram schematically shows a portion of the components of vehicle 1. Vehicle 1 is configured to include a rotating body R, a sensor element 10, and an ECU 20.

[0035] The rotating body R is the object on which the ECU 20 calculates its revolutions. Examples of rotating bodies R in the vehicle 1 include axles, crankshafts, transmission gears, and pulleys in the transmission.

[0036] The sensor element 10 is a semiconductor element that detects rotation of the rotating body R and outputs a predetermined pulse at a cycle corresponding to the number of revolutions thereof. The sensor element 10 is driven by a power supply (Vin) supplied from the vehicle. Figure 1

[0037] The sensor element 10 detects rotation of the rotating body R, for example, using magnetism or the like, and switches the output to High or Low in correspondence with the number of revolutions detected to generate an output pulse. In the present embodiment, the interval of the pulse is made shorter as the number of revolutions rises. Further, in the present embodiment, the number of revolutions is expressed by the interval of the pulse, but the number of revolutions can also be expressed by the pulse width.

[0038] The input side of the sensor element 10 is connected to the power supply (Vin), and the output side is connected to ground via a load resistor. When the sensor element 10 outputs High, a predetermined voltage (typically, a voltage obtained by subtracting the operating voltage of the sensor element 10 from Vin) is applied at Vout based on the output of the comparator. In addition, when the sensor element 10 outputs Low, a predetermined voltage is applied at Vout.

[0039] The ECU 20 is a computer that calculates the number of revolutions of the rotating body R. The ECU 20 can be configured as a computer having a processor (CPU, GPU, or the like), a main storage device (RAM, ROM, or the like), and an auxiliary storage device (EPROM, a hard disk drive, a removable medium, or the like). An operating system (OS), various programs, various tables, and the like are stored in the auxiliary storage device, and by executing the programs stored therein, each function (software module) that conforms to the predetermined purpose described later can be realized. However, part or all of the functions can also be realized as hardware modules by an ASIC, an FPGA, or the like.

[0040] The ECU 20 is configured to include an arithmetic device 201 and a storage device 202.

[0041] The arithmetic device 201 is an arithmetic unit that realizes various functions of the ECU 20 by executing predetermined programs. The arithmetic device 201 can be realized by a hardware processor such as a CPU, for example. In addition, the arithmetic device 201 can be configured to include a RAM (Random Access Memory), a ROM (Read Only Memory), a cache memory, or the like.

[0042] ​In the present embodiment, the arithmetic device 201 of the ECU 20 is configured to include each module of the input voltage detection section 211, the output voltage detection section 212, and the arithmetic section 213. Each module can be realized by executing a program stored in the storage device 202 described later by a CPU or the like. The information processing performed by the software module is synonymous with the information processing performed by the arithmetic device 201 (CPU or the like).

[0043] The input voltage detection section 211 acquires the power supply voltage (i.e., Vin) supplied from the vehicle 1 to the sensor element 10. The power supply voltage acquired by the input voltage detection section 211 is used by the arithmetic section 213 for abnormality determination. Details will be described later.

[0044] The output voltage detection section 212 acquires the output voltage (i.e., Vout) output from the sensor element 10. By determining the output voltage output from the sensor element 10 using a threshold value, it is possible to determine whether the output of the sensor element 10 is high or low. The output voltage acquired by the output voltage detection section 212 is used by the arithmetic section 213 for arithmetic of the rotational speed of the rotating body R.

[0045] The arithmetic section 213 performs arithmetic of the rotational speed of the rotating body R on the basis of the output voltage acquired by the output voltage detection section 212. Specifically, the arithmetic section 213 determines the period of the output pulse on the basis of the output voltage acquired by the output voltage detection section 212. For example, it is possible to determine the period of the output pulse by timing the timing at which the output changes from high to low. The arithmetic section 213 stores data describing the relationship between the period of the output pulse and the rotational speed of the rotating body R, and it is possible to calculate the rotational speed of the rotating body R on the basis of the data.

[0046] Further, the arithmetic section 213 determines whether the power supply voltage of the sensor element 10 acquired by the input voltage detection section 211 is an abnormal value, and overwrites the rotational speed calculated on the basis of the output voltage when the power supply voltage is an abnormal value. Details will be described later.

[0047] The storage device 202 is a unit for storing information, and is configured by a storage medium such as a RAM, a magnetic disk, a flash memory, or the like. The storage device 202 stores a program executed by the arithmetic device 201, data used by the program, and the like.

[0048] Further, regarding the specific structure of the ECU 20, omission, replacement, and addition of the constituent elements can be appropriately made depending on the embodiment. For example, the ECU 20 can include a plurality of hardware processors. The hardware processor can be configured by a microprocessor, an FPGA, a GPU, or the like. In addition, an input / output device (e.g., an optical drive or the like) other than the illustrated elements can be attached. In addition, the ECU 20 can be configured by a plurality of computers. In this case, the hardware structures of the respective computers can be identical or different.

[0049] [Summary of abnormality detection]

[0050] Next, a detection abnormality of the rotation speed caused by the power supply voltage will be described.

[0051] Figure 2 A graph of the output voltage of the sensor element 10 is shown. The sensor element 10 normally outputs high, and switches the output to low at every rotation of the rotating body R. However, when the voltage supplied to the sensor element 10 is lower than a predetermined value (referred to as the minimum drive voltage), the output voltage sometimes fluctuates even if no rotation is detected.

[0052] Here, it is assumed that a power supply voltage of 5.4 V is supplied to the sensor element 10. In addition, the minimum power supply voltage (minimum drive voltage) at which the sensor element 10 can be driven is assumed to be 4.0 V. In addition, the output voltage when the output of the sensor element 10 is high is assumed to be 1.4 V.

[0053] When the power supply voltage is 5.4 V, the output voltage when the output is high is 1.4 V, and thus 4.0 V is applied to the sensor element 10. Here, when the power supply voltage decreases to 4.6 V, the voltage applied to the sensor element 10 is the value obtained by subtracting the output voltage from the power supply voltage, and thus decreases to 3.2 V.

[0054] Here, since the voltage applied to the sensor element 10 is lower than the minimum drive voltage, the operation of the sensor element 10 stops. As a result, the output voltage decreases from 1.4 V.

[0055] When the output voltage decreases to, for example, 0.6 V, the voltage applied to the sensor element 10 relatively increases, and as a result, it returns to 4.0 V. Then, the sensor element 10 resumes the operation and wants to output high, and thus the output increases to 1.4 V, and as a result, the voltage applied to the sensor element 10 again becomes lower than 4.0 V, the sensor element 10 stops again, and the output voltage decreases.

[0056] As such, when the power supply voltage is insufficient, the output of the sensor element 10 becomes an oscillation generating state. In such a state, the output voltage becomes a pulse-shaped waveform, and thus the operation section 213 generates a malfunction, and erroneously operates the number of rotations of the rotating body R.

[0057] When the number of rotations of the rotating body R is erroneously operated, a contradiction occurs in the vehicle system, and thus an error in the output of the self-diagnosis system of the vehicle (for example, AT solenoid abnormality or the like when the subject is a transmission), or a failure such as illumination of a warning lamp occurs.

[0058] In the present embodiment, in order to cope with such a situation, the power supply voltage supplied to the sensor element 10 is monitored, and when the power supply voltage is lower than a predetermined threshold value (hereinafter referred to as threshold voltage), the operation section 213 is caused to interrupt the operation of the number of rotations.

[0059] Here, the threshold voltage refers to the sum of the minimum drive voltage of the sensor element 10 and the output voltage when the sensor element 10 outputs high (i.e., the maximum value of the pulse voltage). For example, when the minimum drive voltage of the sensor element 10 is 4.0 V and the output voltage when the sensor element 10 outputs high is 1.4 V, the threshold voltage is 5.4 V. Further, the minimum drive voltage refers to the minimum voltage at which the sensor element 10 can output a pulse as designed. When the voltage of the power source supplied to the sensor element 10 falls below 5.4 V, both the condition "the potential difference between Vin and Vout (the voltage supplied to the sensor element 10) is 4.0 V or more" and the condition "the potential difference between Vout and GND (the output voltage) is 1.4 V or more" no longer hold true. That is, when the power source voltage falls below 5.4 V, the sensor element 10 can no longer output a normal pulse. In this case, the operation section 213 interrupts the operation of the number of revolutions based on the pulse and, for example, overwrites the number of revolutions as the operation result with zero. Thus, it is possible to prevent the detection of an abnormal number of revolutions in the case where the power source voltage has fallen.

[0060] [PROCESS FLOW]

[0061] Next, the flow of the process performed by the ECU 20 will be described.

[0062] Figure 3 A flowchart of the process performed by the ECU 20 while the vehicle 1 is running. The illustrated process can be started at an arbitrary timing when the running system of the vehicle 1 is activated.

[0063] First, in step S11, the operation section 213 sets the threshold voltage. The threshold voltage is determined based on the specifications of the sensor element 10 as the object. Further, when the ECU 20 governs a plurality of sensor elements, different threshold voltages can be used for each sensor element. In the case of the aforementioned example, the threshold voltage is 5.4 V.

[0064] When the minimum drive voltage of the sensor element 10 is XI [V] and the output voltage when the sensor element 10 outputs high is X2 [V], the threshold voltage is XI + X2 [V].

[0065] Next, in step S12, the operation section 213 determines whether the power source voltage supplied to the sensor element 10 falls below the threshold voltage. The operation section 213 acquires the power source voltage supplied to the sensor element 10 via the input voltage detection section 211.

[0066] When the power supply voltage supplied to the sensor element 10 is higher than the threshold voltage, the process shifts to step S13, and the number of revolutions of the rotating body R is calculated by the arithmetic operation section 213 based on the output voltage from the sensor element 10. The output voltage from the sensor element 10 can be acquired via the output voltage detection section 212. The number of revolutions of the rotating body R is calculated by the arithmetic operation section 213 based on, for example, the period of the pulse (for example, the period of the rise or the period of the fall of the output voltage).

[0067] When the power supply voltage supplied to the sensor element 10 is lower than the threshold voltage, the process shifts to step S14. In step S14, the number of revolutions of the rotating body R is set to zero regardless of the output from the sensor element 10 by the arithmetic operation section 213. Also in this example, the number of revolutions of the rotating body R is set to zero regardless of the output from the sensor element 10, but the arithmetic operation section 213 can process the output voltage of the sensor element 10 as a fixed value. For example, the arithmetic operation section 213 can process the output of the sensor element 10 as a fixed value that is high or low.

[0068] As described above, for the sensor element as the object, the ECU 20 of the first embodiment performs the calculation of the number of revolutions with the condition that the power supply voltage is higher than the threshold voltage, and does not perform the calculation of the number of revolutions when the power supply voltage is lower than the threshold voltage. According to this structure, the misjudgment of the number of revolutions caused by the reset of the sensor element can be suppressed.

[0069] (Modified Example)

[0070] The above-described embodiment is merely an example, and the present disclosure can be implemented as appropriate with variations without departing from the gist thereof.

[0071] For example, the processes and units described in the present disclosure can be freely combined and implemented as appropriate without causing technical contradictions.

[0072] In addition, the processes described as being performed by one device can be executed by multiple devices in a shared manner. Alternatively, the processes described as being performed by different devices can be executed by one device. In a computer system, the hardware structure (server structure) by which each function is implemented can be changed flexibly.

[0073] The present disclosure can also be realized by providing a computer program that realizes the functions described in the above-described embodiments to a computer and reading and executing the program by one or more processors possessed by the computer. Such a computer program can be provided to the computer by a non-transitory computer-readable storage medium that can be connected to a system bus of the computer, or can be provided to the computer via a network. The non-transitory computer-readable storage medium includes, for example, any type of disk (a floppy disk (registered trademark), a hard disk drive (HDD), and the like), an optical disk (a CD-ROM, a DVD disk / Blu-ray disk, and the like), and the like, a read only memory (ROM), a random access memory (RAM), an EPROM, an EEPROM, a magnetic card, a flash memory, an optical card, and any type of medium suitable for storing electronic instructions.

Claims

1. An information processing apparatus, wherein the information processing apparatus has a control section that performs the following processing: based on a period of a pulse output by a first sensor element, a predetermined physical quantity that is a detection target of the first sensor element is calculated; and when a power supply voltage supplied to the first sensor element is equal to or less than a predetermined voltage, the physical quantity is regarded as a predetermined value regardless of an output of the first sensor element, wherein the predetermined voltage is a value obtained by adding a minimum driving voltage of the first sensor element to a maximum value of a pulse voltage output by the first sensor element.

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