A power-source monitoring apparatus according to an embodiment includes an abnormality detecting unit, a measurement unit, and a recording unit. The abnormality detecting unit detects an abnormality in a power source. The power source supplies electric power to an autonomous driving apparatus of a vehicle. The measurement unit measures an elapsed time interval from a time point at which the abnormality detecting unit detects an abnormality in the power source. The recording unit records therein the elapsed time interval measured by the measurement unit.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2018-184579, filed on Sep. 28, 2018, the entire contents of which are incorporated herein by reference.

FIELD

The embodiment discussed herein is directed to a power-source monitoring apparatus, a power-source controlling system, and a power-source monitoring method.

BACKGROUND

Conventionally, there has been known a technology that supplies, when the voltage of a main power source for supplying electric power to a load is reduced, electric power to the load from a reserve power source, so as to extend an operation time interval of the load (see Japanese Laid-open Patent Publication No. 2016-094297, for example).

In a case where this technology is employed for an autonomous driving apparatus of a vehicle, for example, electric power is supplied to the autonomous driving apparatus from the reserve power source when an abnormality occurs in a power source during autonomous driving, so that it is possible to gain a time interval until a driver starts to perform manual driving instead of the autonomous driving apparatus.

However, at present, it is difficult to specify that a cause of a vehicle accident is which of a negligence of the autonomous driving apparatus and a negligence of the driver, when the vehicle accident occurs after an abnormality has occurred in the power source.

SUMMARY

A power-source monitoring apparatus (3) according to an embodiment includes an abnormality detecting unit (51), a measurement unit (52), and a recording unit (42). The abnormality detecting unit (51) detects an abnormality in a power source (11). The power source (11) supplies electric power to an autonomous driving apparatus (13) of a vehicle. The measurement unit (52) measures an elapsed time interval from a time point at which the abnormality detecting unit (51) detects an abnormality in the power source (11). The recording unit (42) records therein the elapsed time interval measured by the measurement unit (52).

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of a power-source monitoring apparatus, a power-source controlling system, and a power-source monitoring method will be described in detail with reference to the accompanying drawings. Moreover, the disclosed technology is not limited to the embodiment described below.

FIG. 1is a block diagram illustrating a configuration example of a power-source controlling system1according to the embodiment. The power-source controlling system1is a system that is connected to a power source11, a reserve power source12, an autonomous driving apparatus13mounted on a vehicle, and a sensor unit14, so as to supply electric power to the autonomous driving apparatus13from the power source11or the reserve power source12.

The power source11includes, for example, a lead storage battery. The reserve power source12includes, for example, a lithium-ion battery. The sensor unit14includes a plurality of sensors such as an image sensor that captures the vicinity of the vehicle, a radar that detects a target object existing in the periphery of the vehicle, a vehicle-speed sensor, and an acceleration sensor.

The autonomous driving apparatus13operates by electric power that is supplied from the power source11or the reserve power source12via the power-source controlling system1, and automatically performs, on the basis of a detection result input from the plurality of sensors included in the sensor unit14, acceleration/deceleration and steering on the vehicle, so as to cause the vehicle to perform autonomous-driving travel.

When the power source11is normal, the power-source controlling system1supplies, from the power source11, electric power to the autonomous driving apparatus13. When an abnormality has occurred in the power source11, for example, disconnection of a battery, reduction in the voltage and/or short of the power source11, and the like; the power-source controlling system1supplies from the reserve power source12electric power to the autonomous driving apparatus13.

The reserve power source12accumulates therein electric power having an amount where the autonomous driving apparatus13is able to be normally operated for a predetermined time interval (for example, ten and several seconds to several minutes) after an abnormality has occurred in the power source11. The above-mentioned predetermined time interval means a time interval sufficient for a driver of an autonomously-driven vehicle to prepare for manual driving when the autonomous driving is to be changed into the manual driving. Furthermore, the predetermined time interval means a time interval during which the autonomous driving apparatus13is able to normally execute autonomous driving by using electric power of the reserve power source12even when an abnormality occurs in the power source11.

Thus, the autonomous driving apparatus13is capable of normally executing autonomous driving during the predetermined time interval even when an abnormality occurs in the power source11. Note that the autonomous driving apparatus13is not able to execute the autonomous driving after the predetermined time interval has elapsed from an occurrence of an abnormality in the power source11.

The power-source controlling system1includes a switching unit2and a power-source monitoring apparatus3. The switching unit2normally supplies electric power, which is input from the power source11, to the autonomous driving apparatus13, and when a switching instruction is input from the power-source monitoring apparatus3, switches the electric power, which is to be supplied to the autonomous driving apparatus13, therefrom into electric power that is input from the reserve power source12.

When switching the electric power, which is to be supplied to the autonomous driving apparatus13, into electric power that is input from the reserve power source12, the switching unit2outputs switching information indicating the fact to the autonomous driving apparatus13. When the switching information is input from the switching unit2, the autonomous driving apparatus13requests a vehicle driver to start manual driving.

The power-source monitoring apparatus3monitors the voltage of the power source11, for example, when the voltage of the power source11is equal to or less than a predetermined threshold, outputs a switching instruction to the switching unit2. Thus, even when an abnormality occurs in the power source11, autonomous driving, which is executed by the autonomous driving apparatus13, is continued by using electric power that is supplied from the reserve power source12during the predetermined time interval, so that the power-source monitoring apparatus3is capable of gaining a time interval until a driver starts to perform manual driving instead of the autonomous driving apparatus13.

The power-source monitoring apparatus3includes a storage4and a control unit5. The storage4is an information storing device, such as a data flash, and includes a setting storage41, a recording unit42, and a determination-result storage43.

The setting storage41stores therein setting information indicating a state where autonomous driving is being set or a state where setting of the autonomous driving is being released. For example, when a driver performs a setting operation of autonomous driving and information indicating the fact is input from the autonomous driving apparatus13, the setting storage41stores therein setting information indicating a state where autonomous driving is being set.

When a driver performs an operation for releasing setting of autonomous driving and information indicating the fact is input from the autonomous driving apparatus13, the setting storage41stores therein setting information indicating a state where setting of the autonomous driving is being released. The recording unit42records therein an elapsed time interval that is measured by a measurement unit52to be mentioned later. The determination-result storage43stores therein a result of determination executed by a determination unit54to be mentioned later.

The control unit5includes a microcomputer, which includes a Central Processing Unit (CPU), a Read Only Memory (ROM), a Random Access Memory (RAM), and the like; and various circuits.

The control unit5includes an abnormality detecting unit51, the measurement unit52, an accident detecting unit53, and the determination unit54, where the CPU executes a program stored in the ROM by using the RAM as a work region so that the abnormality detecting unit51, the measurement unit52, the accident detecting unit53, and the determination unit54function.

A part or all of the abnormality detecting unit51, the measurement unit52, the accident detecting unit53, and the determination unit54, which are included in the control unit5, may be constituted of hardware such as an Application Specific Integrated Circuit (ASIC) and a Field Programmable Gate Array (FPGA).

Each of the abnormality detecting unit51, the measurement unit52, the accident detecting unit53, and the determination unit54, which are included in the control unit5, executes a corresponding process described below. An inner configuration of the control unit5is not limited to the configuration illustrated inFIG. 1, and may have another configuration as long as the configuration is for executing information processing to be mentioned later.

When the voltage of the power source11is monitored and the voltage of the power source11is equal to or less than a predetermined threshold, the abnormality detecting unit51detects an abnormality in the power source11. When detecting the abnormality in the power source11, the abnormality detecting unit51outputs information indicating the fact to the measurement unit52, and further outputs a switching instruction to the switching unit2.

The measurement unit52is a timer that measures an elapsed time interval from a time point at which the abnormality detecting unit51detects an abnormality in the power source11, in other words, an elapsed time interval from a time point at which electric power starts to be supplied from the reserve power source12to the autonomous driving apparatus13. The measurement unit52sequentially updates the measured time interval and outputs the updated measured time interval to the recording unit42so as to cause the recording unit42to record therein the updated measured time interval.

Thus, for example, in a case where a vehicle accident occurs after an occurrence of an abnormality in the power source11, when the recorded elapsed time interval is read out from the recording unit42, it is possible to specify that a cause of the vehicle accident is which of a negligence of the autonomous driving apparatus13and a negligence of a driver.

Specifically, when the elapsed time interval that is read out from the recording unit42is within a predetermined time interval (time interval capable of ensuring normal operation of autonomous driving apparatus13using reserve power source12), a vehicle accident has occurred during autonomous driving, so that it is possible to specify that a cause is a negligence of the autonomous driving apparatus13.

When the elapsed time interval read out from the recording unit42is not within the predetermined time interval, namely, when the elapsed time interval exceeds the predetermined time interval, a vehicle accident has occurred during manual driving, so that it is possible to specify that a cause is a negligence of a driver.

In a case of a vehicle accident whose scale of damage is comparatively large, the measurement unit52stops measuring an elapsed time interval due to breakage, on the other hand, in a case of a vehicle accident whose scale of damage is comparatively small, there presents possibility of continuing to measure the elapsed time interval even after the accident. Thus, the control unit5is configured to include the accident detecting unit53.

The accident detecting unit53detects an occurrence of a vehicle accident on the basis of a detection result of an acceleration sensor included in the sensor unit14. For example, when the acceleration sensor detects an acceleration exceeding a predetermined threshold, the accident detecting unit53detects an occurrence of a vehicle accident.

When detecting an occurrence of a vehicle accident, the accident detecting unit53outputs information indicating the fact to the measurement unit52and the determination unit54. When the information indicating that an occurrence of a vehicle accident is detected is input from the accident detecting unit53, the measurement unit52ends the measurement of the elapsed time interval. Thus, the recording unit42is capable of recording a precise elapsed time interval from a time point when an abnormality is detected in the power source11to a time point when a vehicle accident has occurred.

When the information indicating that an occurrence of a vehicle accident is detected is input from the accident detecting unit53, the determination unit54determines whether or not the elapsed time interval recorded in the recording unit42is within a predetermined time interval, and stores a determination result in the determination-result storage43.

Thus, when a vehicle accident occurs after an occurrence of an abnormality in the power source11, with reference to a determination result whether or not an elapsed time interval stored in the determination-result storage43is within a predetermined time interval, it is possible to easily specify that a cause of the vehicle accident is which of a negligence of the autonomous driving apparatus13and a negligence of a driver.

Moreover, when an elapsed time interval recorded in the recording unit42is within the predetermined time interval, the determination unit54may determine that a cause of the vehicle accident is a negligence of the autonomous driving apparatus, and when the elapsed time interval recorded in the recording unit42is not within the predetermined time interval, the determination unit54may determine that a cause of the vehicle accident is a negligence of a driver.

When determining a cause of a vehicle accident in this manner, the determination unit54stores a determination result of an accident cause in the determination-result storage43. Thus, when a vehicle accident occurs after an occurrence of an abnormality in the power source11, with reference to only the determination result of the accident cause stored in the determination-result storage43, it is possible to immediately specify that a cause of the vehicle accident is which of a negligence of the autonomous driving apparatus13and a negligence of a driver.

Moreover, the determination unit54may determine, on the basis of setting information stored in the setting storage41, whether a cause of a vehicle accident is a negligence of the autonomous driving apparatus or a negligence of a driver. For example, even in a state where the elapsed time interval recorded in the recording unit42is within a predetermined time interval, when setting information indicating a state where setting of the autonomous driving is being released is stored in the setting storage41, the determination unit54determines a cause of a vehicle accident to be a negligence of a driver.

Thus, when a vehicle accident occurs before the predetermined time interval has elapsed from a time when an abnormality occurred in the power source11, it is possible to prevent the determination unit54from erroneously determining, even during manual driving, that a cause of the vehicle accident is a negligence of the autonomous driving apparatus.

Next, with reference toFIG. 2, one example of operations of the power-source controlling system1according to the embodiment will be explained.FIG. 2is a timing diagram illustrating operations of the power-source controlling system1according to the embodiment. Herein, a case will be explained in which an abnormality occurs in the power source11at a time point t1while the autonomous driving apparatus is operating (during autonomous driving).

InFIG. 2, there are illustrated from the top, a state of the power source11, a state of the reserve power source, an abnormality detection state of the power source11by the abnormality detecting unit51, an outputting state of a switching instruction by the abnormality detecting unit51, a measurement state of an elapsed time interval by the measurement unit52, an operation state of the autonomous driving apparatus13, and the responsibility of a vehicle accident.

As illustrated inFIG. 2, in the power-source controlling system1, when the voltage of the power source11is equal to or less than a threshold at the time point t1, the abnormality detecting unit51detects an abnormality in the power source11. The abnormality detecting unit51outputs a switching instruction to the switching unit2at the time point t1. Thus, the autonomous driving apparatus13is capable of continuing autonomous driving by using electric power supplied from the reserve power source12during a predetermined time interval after the time point t1.

The abnormality detecting unit51outputs, to the measurement unit52, information indicating detection of an abnormality in the power source11at the time point t1. The measurement unit52starts to measure an elapsed time interval from the time point t1. Next, during a time interval from an occurrence of an abnormality in the power source11to a time point t2that is after a predetermined time interval of the occurrence of the abnormality, the voltage of the reserve power source12is gradually reduced to fall below an operable voltage of the autonomous driving apparatus13at the time point t2.

Thus, the autonomous driving apparatus13has been changed into a non-operation state since the time point t2. As described above, in the case illustrated inFIG. 2, during a time interval before the time point t2, the autonomous driving apparatus13operates to cause a vehicle to travel by using autonomous driving.

As described above, when an abnormality occurs in the power source11and switching information is input from the switching unit2, the autonomous driving apparatus13requests a driver to start manual driving. Thus, a driver is supposed to prepare for manual driving during a time interval from the occurrence of the abnormality in the power source11until a predetermined time interval has therefrom elapsed, and is further supposed to start manual driving from at least the time point t2.

Thus, in the case illustrated inFIG. 2, when a vehicle accident occurs before the time point t2, the determination unit54determines that a cause of the vehicle accident is a negligence of the autonomous driving apparatus13. When a vehicle accident occurs after the time point t2, the determination unit54determines that a cause of the vehicle accident is a negligence of a driver.

Next, with reference toFIG. 3, a process to be executed by the autonomous driving apparatus13according to the embodiment will be explained.FIG. 3is a flowchart illustrating one example of the process to be executed by the autonomous driving apparatus13according to the embodiment. When an ignition switch (hereinafter, may be referred to as “IG”) of a vehicle is turned ON, the autonomous driving apparatus13repeatedly execute the process illustrated inFIG. 3at a predetermined period.

When the IG is turned ON, the autonomous driving apparatus13determines whether or not autonomous driving is set (Step S101). When the autonomous driving apparatus13determines that autonomous driving is not set (Step S101: No), end the processing, and the processing is restarted from Step S101.

When determining that autonomous driving is set (Step S101: Yes), the autonomous driving apparatus13starts autonomous driving (Step S102), and determines whether or not there presents switching from the power source11into the reserve power source12(Step S103).

When determining that there presents no switching into the reserve power source12(Step S103: No), the autonomous driving apparatus13determines whether or not the setting of the autonomous driving is released (Step S107). When determining that the setting of autonomous driving is not released (Step S107: No), the autonomous driving apparatus13shifts the processing to Step S103.

When determining that the setting of autonomous driving is released (Step S107: Yes), the autonomous driving apparatus13ends the autonomous driving (Step S106), and ends the processing. Next, the autonomous driving apparatus13restarts the processing from Step S101.

When determining that there presents switching into the reserve power source12(Step S103: Yes), the autonomous driving apparatus13makes a start request for manual driving to a driver (Step S104). Next, the autonomous driving apparatus13determines whether or not a predetermined time interval has elapsed (Step S105). When determining that the predetermined time interval has not elapsed yet (Step S105: No), the autonomous driving apparatus13repeats the determination process of Step S105until the predetermined time interval has elapsed.

When determining that the predetermined time interval has elapsed (Step S105: Yes), the autonomous driving apparatus13ends the autonomous driving (Step S106), and ends the processing. When the IG is turned OFF during execution the process illustrated inFIG. 3, the autonomous driving apparatus13ends the processing at this time point.

Next, with reference toFIG. 4, one example of a process to be executed by the control unit5of the power-source monitoring apparatus3according to the embodiment will be explained.FIG. 4is a flowchart illustrating one example of the process to be executed by the control unit5of the power-source monitoring apparatus3according to the embodiment.

When the IG of the vehicle is turned ON, the control unit5starts a process illustrated inFIG. 4. When the IG is turned OFF during execution of the process illustrated inFIG. 4, the control unit5ends the processing at this time point.

When the IG is turned ON, the control unit5supplies electric power from the power source11to the autonomous driving apparatus13(Step S201). Subsequently, the control unit5determines whether or not an abnormality in the power source11is detected (Step S202).

When determining that an abnormality is not detected in the power source11(Step S201: No), the control unit5shifts the processing to Step S201. When determining that an abnormality is detected in the power source11(Step S202: Yes), the control unit5switches the power source into the reserve power source12(Step S203), and starts to measure and record the elapsed time interval (Step S204).

Next, the control unit5determines whether or not an occurrence of a vehicle accident is detected (Step S205). When determining that an occurrence of a vehicle accident is not detected (Step S205: No), the control unit5repeats the determination process of Step S205until an occurrence of a vehicle accident is detected.

When determining that an occurrence of a vehicle is detected (Step S205: Yes), the control unit5ends measuring and recording the elapsed time interval (Step S206). Subsequently, the control unit5determines whether or not autonomous driving is being set (Step S207).

When determining that autonomous driving is not being set (Step S207: No), the control unit5shifts the processing to Step S211. When determining that autonomous driving is being set (Step S207: Yes), the control unit5determines whether or not an elapsed time interval from the switching into the reserve power source12is within a predetermined time interval (Step S208).

When determining that the elapsed time interval is not within the predetermined time interval (Step S208), the control unit5determines that a cause of the vehicle accident is a negligence of a driver (Step S211), and shifts the processing to Step S210.

When determining that the elapsed time interval is within the predetermined time interval (Step S208: Yes), the control unit5determines that a cause of the vehicle accident is a negligence of the autonomous driving apparatus (Step S209), and shifts the processing to Step S210. In Step S210, the control unit5stores the determination result of Step S209or Step S211, and ends the processing.

The above-mentioned embodiment is merely one example and may be variously modified. For example, the power-source monitoring apparatus3may cause a display provided in a vehicle to display a determination result of the determination unit54. Thus, when a vehicle accident has occurred after an occurrence of an abnormality in the power source11, it is possible to more easily specify that the responsibility of a vehicle accident is which of a negligence of an autonomous driving apparatus and a negligence of a driver.

The power-source monitoring apparatus3may have a configuration in which the measurement unit52includes a plurality of timers. In a case of this configuration, for example, the determination unit54may determine whether or not an average value of measured time intervals of the timers is within a predetermined time interval, so as to determine whether the responsibility of a vehicle accident is a negligence of the autonomous driving apparatus13or a negligence of a driver.

The determination unit54may determine, for each of the measured time intervals measured by the timers, whether or not the corresponding measured time interval is within a predetermined time interval, and input the determination results to the AND logic circuit, so as to determine, by using the AND logic circuit, whether the responsibility of the vehicle accident is a negligence of the autonomous driving apparatus13or a negligence of the driver. Thus, it is possible to improve the reliability of the determination result determined by the determination unit54.

When the IG of the vehicle is turned OFF under the state where a vehicle accident has not occurred after the measuring of the elapsed time interval was started, the measurement unit52resets the elapsed time interval recorded in the recording unit42. Thus, the measurement unit52is capable of starting measurement of the elapsed time interval from zero when an abnormality occurs in the power source11during the next travel.