Information processing apparatus

Abstract

To suppress erroneous detection that occurs when the power supply voltage of a sensor drops.SOLUTION: A predetermined physical quantity to be detected by the first sensor element is calculated based on a period of a pulse output from the first sensor element, and when a power supply voltage supplied to the first sensor element is equal to or lower than a predetermined voltage, the physical quantity is regarded as a predetermined value regardless of an 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 from the first sensor element.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] There are technologies for improving the reliability of sensors installed in automobiles. In this regard, for example, Patent Document 1 discloses a device that improves reliability by prohibiting detection of rotation when a sensor that detects the rotation of a rotating body is suspected to be erroneous due to noise or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-214905 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-045354 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure aims to suppress false detection that occurs when the power supply voltage of a sensor drops. [Means for solving the problem]

[0005] One aspect of the present disclosure is An information processing device having a control unit that calculates a predetermined physical quantity that is to be detected by a first sensor element based on 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 lower than a predetermined voltage, treats the physical quantity as a predetermined value regardless of the output of the first sensor element, wherein the predetermined voltage is a value obtained by adding the minimum driving voltage of the first sensor element and the maximum value of the pulse voltage output by the first sensor element.

[0006] Other aspects include an information processing method executed by the above-mentioned device, a program for causing a computer to execute the information processing method, or a computer-readable storage medium non-temporarily storing the program. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to suppress erroneous detection that occurs when the power supply voltage of the sensor drops. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing the configuration of a sensor element and an ECU. [Figure 2] FIG. 4 is a diagram illustrating input and output voltages of a sensor element. [Figure 3] 3 is a flowchart of a process executed by an ECU. DETAILED DESCRIPTION OF THE INVENTION

[0009] The ECU in an automobile is connected to many on-board sensors and senses multiple physical quantities necessary for the vehicle to run.

[0010] A typical example of an in-vehicle sensor is a sensor that detects the rotation of a rotating body. For example, a sensor detects the rotation of a drive gear, primary pulley, secondary pulley, etc. included in a transmission, and the ECU calculates the rotation speed based on the signal output by the sensor, thereby enabling appropriate control of gear changes.

[0011] These on-board sensors must be driven by a voltage above a certain value, but in many cases, the power supply voltage in a vehicle system drops, making it impossible to calculate accurate values.

[0012] For example, consider a sensor element that outputs a pulse signal at a period corresponding to the rotation speed of an object, where the sensor element outputs one pulse for each rotation of the object. Now, let's consider a case where the power supply voltage supplied to the sensor element drops. When the power supply voltage supplied to the sensor element drops, the element's operation is reset, which can cause the voltage output from the sensor element to fluctuate. If this voltage fluctuation is confused with a normal pulse, an incorrect rotation speed will be calculated, causing an internal contradiction within the ECU, which can result in an error being output. The information processing device according to the present disclosure solves such problems.

[0013] An information processing device according to one embodiment of the present disclosure includes a control unit that calculates a predetermined physical quantity to be detected by a first sensor element based on 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 lower than a predetermined voltage, treats the physical quantity as a predetermined value regardless of the output of the first sensor element, wherein the predetermined voltage is a value obtained by adding the minimum driving voltage of the first sensor element and the maximum value of the pulse voltage output by the first sensor element.

[0014] The information processing device according to the present disclosure is typically an ECU (Electric Control Unit) mounted on a vehicle, and is connected to a first sensor element. The first sensor element is an element that outputs a predetermined physical quantity to be detected (for example, vehicle speed, gear rotation speed, etc.) as a pulse signal. The control unit of the information processing device can calculate the predetermined physical quantity based on the period of the pulse acquired from the first sensor element.

[0015] The control unit can monitor the power supply voltage supplied to the first sensor element. If the power supply voltage is equal to or lower than a predetermined voltage, the control unit regards the physical quantity as a predetermined value. In other words, if the power supply voltage supplied to the first sensor element is insufficient, the control unit regards the output pulse as unreliable and regards the value that should be calculated based on the output pulse as a predetermined value (e.g., zero).

[0016] The predetermined voltage is the sum of the minimum drive 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 when high). If the voltage supplied to the first sensor element is less than the sum of the minimum drive voltage of the sensor element and the voltage when high, it will be impossible to output a pulse with a normal waveform and satisfy the minimum drive voltage. Therefore, in such cases, treating the value obtained by calculation as a fixed value can prevent erroneous determination.

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The configurations of the following embodiments are examples, and the present disclosure is not limited to the configurations of the embodiments.

[0018] (First embodiment) An overview of the system according to the first embodiment will be described. The system according to this embodiment is a system in which a sensor element 10 detects the rotation of a rotating body R of an automobile, and an ECU 20 calculates the rotation speed.

[0019] The configuration of each device that makes up the system will be described. First, a description will be given of the components of the vehicle 1. Fig. 1 is a diagram schematically illustrating some of the components of the vehicle 1. The vehicle 1 is configured to include a rotating body R, a sensor element 10, and an ECU 20.

[0020] The rotating body R is an object whose rotation speed is calculated by the ECU 20. Examples of the rotating body R of the vehicle 1 include an axle, a crankshaft, a drive gear or pulley of a transmission, and the like.

[0021] The sensor element 10 is a semiconductor element that detects the rotation of the rotating body R and outputs a predetermined pulse at a period corresponding to the rotation speed. The sensor element 10 is driven by a power source (Vin in FIG. 1) supplied from the vehicle. The sensor element 10 detects, for example, by magnetism or the like, that the rotating body R is rotating, and switches its output between High and Low depending on the detected rotation speed, thereby generating an output pulse. In this embodiment, the sensor element 10 is configured so that the pulse interval becomes shorter as the rotation speed increases. Note that, although the rotation speed is expressed by the pulse interval in this embodiment, the rotation speed may also be expressed by the pulse width.

[0022] The input side of the sensor element 10 is connected to a power supply (Vin), and the output side is grounded via a load resistor. When the sensor element 10 outputs a high signal, a predetermined voltage (typically, Vin minus the operating voltage of the sensor element 10) is applied to Vout based on the output of the comparator. When the sensor element 10 outputs a low signal, a predetermined voltage is applied to Vout.

[0023] The ECU 20 is a computer that calculates the rotation speed of the rotating body R. The ECU 20 can be configured as a computer having a processor (CPU, GPU, etc.), a main memory device (RAM, ROM, etc.), and an auxiliary memory device (EPROM, hard disk drive, removable media, etc.). The auxiliary memory device stores an operating system (OS), various programs, various tables, etc., and by executing the programs stored therein, various functions (software modules) that match predetermined purposes, as described below, can be realized. However, some or all of the functions may be realized as hardware modules using hardware circuits such as ASICs and FPGAs.

[0024] The ECU 20 includes an arithmetic unit 201 and a storage unit 202 . The arithmetic device 201 is a calculation unit that executes predetermined programs to realize various functions of the ECU 20. The arithmetic device 201 can be realized by, for example, a hardware processor such as a CPU. The arithmetic device 201 may also be configured to include a RAM (Random Access Memory), a ROM (Read Only Memory), a cache memory, etc.

[0025] In this embodiment, the arithmetic unit 201 included in the ECU 20 includes modules of an input voltage detection unit 211, an output voltage detection unit 212, and a calculation unit 213. Each module may be realized by a CPU or the like executing a program stored in a storage device 202 (described later). The information processing executed by the software module is synonymous with the information processing executed by the arithmetic unit 201 (CPU or the like).

[0026] The input voltage detection unit 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 unit 211 is used by the calculation unit 213 for abnormality determination. Details will be described later.

[0027] The output voltage detection unit 212 acquires the output voltage (i.e., Vout) output from the sensor element 10. The output voltage from the sensor element 10 is determined based on a threshold value. , it can be determined whether the output of the sensor element 10 is High or Low. The output voltage acquired by the output voltage detection unit 212 is used by the calculation unit 213 to calculate the rotation speed of the rotating body R.

[0028] The calculation unit 213 calculates the rotation speed of the rotating body R based on the output voltage acquired by the output voltage detection unit 212. Specifically, the calculation unit 213 determines the period of the output pulse based on the output voltage acquired by the output voltage detection unit 212. The period of the output pulse can be determined, for example, by timing the timing at which the output changes from High to Low. The calculation unit 213 stores data describing the relationship between the period of the output pulse and the rotation speed of the rotating body R, and can determine the rotation speed of the rotating body R based on this data.

[0029] Furthermore, the calculation unit 213 determines whether the power supply voltage of the sensor element 10 acquired by the input voltage detection unit 211 is an abnormal value, and if the power supply voltage is an abnormal value, overwrites the rotation speed calculated based on the output voltage. Details will be described later.

[0030] The storage device 202 is a means for storing information, and is configured with storage media such as RAM, a magnetic disk, a flash memory, etc. The storage device 202 stores programs executed by the arithmetic device 201, data used by the programs, etc.

[0031] The specific configuration of the ECU 20 may include omissions, substitutions, and additions of components as appropriate depending on the embodiment. For example, the ECU 20 may include multiple hardware processors. The hardware processors may be configured with a microprocessor, FPGA, GPU, etc. Furthermore, input / output devices other than those illustrated (e.g., optical drives) may be added. Furthermore, the ECU 20 may be configured with multiple computers. In this case, the hardware configurations of the computers may or may not be the same.

[0032] [Anomaly detection overview] Next, an abnormality in the detection of the rotation speed caused by the power supply voltage will be described. 2 is a diagram illustrating the output voltage of the sensor element 10. The sensor element 10 normally outputs a high signal, and switches the output to a low signal each time the rotating body R rotates once. However, if the voltage supplied to the sensor element 10 falls below a predetermined value (referred to as the minimum drive voltage), the output voltage may fluctuate even though no rotation is detected.

[0033] Here, it is assumed that a power supply voltage of 5.4 V is supplied to the sensor element 10. It is also assumed that the minimum power supply voltage (minimum drive voltage) at which the sensor element 10 can be driven is 4.0 V. It is also assumed that the output voltage when the output of the sensor element 10 is High is 1.4 V.

[0034] When the power supply voltage is 5.4 V, the output voltage when the output is High is 1.4 V, so 4.0 V is applied to the sensor element 10. If the power supply voltage drops to 4.6 V, the voltage applied to the sensor element 10 will be the power supply voltage minus the output voltage, and will therefore drop to 3.2 V. At this point, the voltage applied to the sensor element 10 falls below the minimum drive voltage, causing the sensor element 10 to stop operating. As a result, the output voltage drops from 1.4V. When the output voltage drops to, for example, 0.6 V, the voltage applied to the sensor element 10 rises relatively, and as a result, it recovers to 4.0 V. Then, the sensor element 10 resumes operation and attempts to output a high signal, so the output rises to 1.4 V. As a result, the voltage applied to the sensor element 10 falls below 4.0 V again, the sensor element 10 stops again, and the output voltage also drops.

[0035] In this way, when the power supply voltage is insufficient, hunting occurs in the output of the sensor element 10. Under such circumstances, the output voltage has a pulse-like waveform, causing the calculation unit 213 to malfunction and erroneously calculate the rotation speed of the rotating body R. If the rotation speed of the rotating body R is calculated incorrectly, an inconsistency will occur within the vehicle system, which may cause the vehicle's self-diagnostic system to output an error (for example, if the target is the transmission, an AT solenoid abnormality, etc.) or may cause a warning light to come on, resulting in other malfunctions.

[0036] To address this issue, the present embodiment monitors the power supply voltage supplied to the sensor element 10, and when the power supply voltage falls below a predetermined threshold (hereinafter referred to as threshold voltage), causes the calculation unit 213 to suspend calculation of the rotation speed.

[0037] Here, the threshold voltage is the sum of the minimum drive voltage of the sensor element 10 and the output voltage when the sensor element 10 outputs a high signal (i.e., the maximum pulse voltage). For example, if the minimum drive voltage of the sensor element 10 is 4.0 V and the output voltage when the sensor element 10 outputs a high signal is 1.4 V, the threshold voltage is 5.4 V. The minimum drive voltage is the minimum voltage at which the sensor element 10 can output pulses as designed. If the power supply voltage supplied to the sensor element 10 falls below 5.4 V, both the condition that "the potential difference between Vin and Vout (the voltage supplied to the sensor element 10) is 4.0 V or more" and the condition that "the potential difference between Vout and GND (the output voltage) is 1.4 V or more" are no longer met. In other words, if the power supply voltage falls below 5.4 V, the sensor element 10 will no longer be able to output normal pulses. In such a case, the calculation unit 213 suspends the calculation of the rotation speed based on the pulses and, for example, overwrites the calculated rotation speed with zero. This makes it possible to prevent an abnormal rotation speed from being detected when the power supply voltage drops.

[0038] [Processing flow] Next, the flow of the processing executed by the ECU 20 will be described. 3 is a flowchart of a process executed by the ECU 20 while the vehicle 1 is traveling. The process shown in the figure may be started at any timing when the traveling system of the vehicle 1 is activated.

[0039] First, in step S11, the calculation unit 213 sets a threshold voltage. The threshold voltage is determined based on the specifications of the target sensor element 10. If the ECU 20 manages multiple sensor elements, a different threshold voltage may be used for each sensor element. In the above example, the threshold voltage is 5.4V. If the minimum drive voltage of the sensor element 10 is X1 [V] and the output voltage when the sensor element 10 outputs High is X2 [V], the threshold voltage is X1+X2 [V].

[0040] Next, in step S12, the calculation unit 213 determines whether the power supply voltage supplied to the sensor element 10 is lower than the threshold voltage. The calculation unit 213 acquires the power supply voltage supplied to the sensor element 10 via the input voltage detection unit 211.

[0041] If the power supply voltage supplied to the sensor element 10 exceeds the threshold voltage, the process proceeds to step S13, where the calculation unit 213 calculates the rotation speed of the rotating body R 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 unit 212. The calculation unit 213 calculates the rotation speed of the rotating body R based on, for example, the pulse period (for example, the period at which the output voltage rises or falls).

[0042] If the power supply voltage supplied to the sensor element 10 is lower than the threshold voltage, the process proceeds to step S14. In step S14, the calculation unit 213 treats the number of rotations of the rotating body R as zero regardless of the output from the sensor element 10. In this example, the sensor element 10 However, the calculation unit 213 may treat the output voltage of the sensor element 10 as a fixed value. For example, the calculation unit 213 may treat the output of the sensor element 10 as a fixed value of High or Low.

[0043] As described above, the ECU 20 according to the first embodiment calculates the rotation speed of a target sensor element only when the power supply voltage is above the threshold voltage, and does not calculate the rotation speed when the power supply voltage is below the threshold voltage. This configuration can prevent erroneous determination of the rotation speed due to resetting of the sensor element.

[0044] (Variation) The above-described embodiment is merely an example, and the present disclosure can be modified and implemented as appropriate within the scope that does not deviate from the gist of the disclosure. For example, the processes and means described in this disclosure can be freely combined and implemented as long as no technical contradiction occurs.

[0045] Furthermore, a process described as being performed by one device may be shared and executed by multiple devices. Alternatively, a process described as being performed by different devices may be executed by a single device. In a computer system, the hardware configuration (server configuration) by which each function is realized can be flexibly changed.

[0046] The present disclosure can also be realized by providing a computer program implementing the functions described in the above embodiments to a computer, and having one or more processors in the computer read and execute the program. Such a computer program may be provided to the computer via a non-transitory computer-readable storage medium connectable to the computer's system bus or via a network. Non-transitory computer-readable storage media include, for example, any type of disk, such as a magnetic disk (e.g., a floppy disk, a hard disk drive (HDD), etc.), an optical disk (e.g., a CD-ROM, a DVD disk, a Blu-ray disk), a read-only memory (ROM), a random access memory (RAM), an EPROM, an EEPROM, a magnetic card, a flash memory, an optical card, or any type of medium suitable for storing electronic instructions. [Explanation of symbols]

[0047] 10. Sensor element 20 ECU 201...Arithmetic unit 202...Storage device R... Rotating body

Claims

[Claim 1] calculating a predetermined physical quantity to be sensed by the first sensor element based on a period of a pulse output by the first sensor element; When a power supply voltage supplied to the first sensor element is equal to or lower than a predetermined voltage, the physical quantity is regarded as a predetermined value regardless of an output of the first sensor element; a control unit that executes the following: the predetermined voltage is a value obtained by adding a minimum drive voltage of the first sensor element and a maximum value of a pulse voltage output by the first sensor element. Information processing device.

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