Brake system

Abstract

To provide a vehicle braking system capable of braking a vehicle which travels autonomously, without the need for a driver even if a failure or an abnormality occurs in a control device.SOLUTION: A braking system includes: a control device which executes control for autonomous traveling; and a first braking device which generates braking force and stop-holding force in a vehicle while it does not receive a suppression request from the control device, and which, while it receives the suppression request from the control device, operates so as to bring about a suppression state without generating the braking force and the stop-holding force in the vehicle. The control device executes processing to output the suppression request to the first braking device while the autonomous traveling of the vehicle is continued.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a braking system for a vehicle that performs autonomous driving.

Background Art

[0002] Conventionally, various braking systems have been proposed that perform braking of a vehicle when a request is given by a driver operation or an output of a control device.

[0003] Patent Document 1 discloses a braking system provided in a vehicle capable of autonomous driving (brake system) that realizes a parking brake with a simple configuration and high holding force. This braking system includes a plurality of brake hydraulic pressure generating devices provided in the same hydraulic transmission path and including a non-electrically operated brake hydraulic pressure generating device. Then, when in a non-energized state or when shifting to a non-energized state after operating an emergency stop button, braking force is generated by the brake hydraulic pressure of the non-electrically operated brake hydraulic pressure generating device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, the development of an autonomous driving system (autonomous driving system of level 4 or higher) in which a vehicle performs autonomous driving without requiring a driver in the vehicle has been in progress. In such an autonomous driving system, a request is given by an output of a control device that executes control related to autonomous driving, and the driving operation of the vehicle is realized.

[0006] Therefore, when applying a conventional braking system that performs braking when a request is given to such an autonomous driving system, there is a risk that the vehicle cannot be properly braked when the output of the control device stops or becomes abnormal due to a defect or abnormality in the control device.

[0007] The present disclosure has been made in view of the above problems, and an object thereof is to provide a braking system that can brake a vehicle without requiring a driver even if a defect or abnormality occurs in a control device in a vehicle that performs autonomous driving.

Means for Solving the Problems

[0008] The braking system according to the first disclosure includes a control device that executes control related to autonomous driving, and a first braking device that, while not receiving a suppression request from the control device, generates a braking force and a stop holding force for the vehicle, and while receiving a suppression request from the control device, operates so as to be in a suppression state where the braking force and the stop holding force for the vehicle are not generated. And, while the vehicle is continuing autonomous driving, the control device executes a process of outputting a suppression request to the first braking device.

[0009] The braking system according to the second disclosure further includes the following features with respect to the braking system according to the first disclosure. The suppression request output by the control device is a signal that follows a rule of turning on and off in a predetermined pattern at predetermined intervals. And, when the signal received from the control device does not follow this rule, the first braking device does not regard the signal as a suppression request.

[0010] The braking system according to the third disclosure further includes the following features with respect to the braking system according to the first or second disclosure. The braking system further includes a second braking device that, when receiving a braking request from the control device, operates to generate a braking force for the vehicle. And, when braking is necessary in autonomous driving, the control device executes a process of outputting a braking request to the second braking device.

[0011] The braking system according to the fourth disclosure further includes the following features with respect to the braking system according to any one of the first to third disclosures. When it is assumed that an abnormality that hinders autonomous driving has occurred in the vehicle, the first braking device generates a braking force and a stop holding force in the vehicle regardless of the suppression request.

Advantages of the Invention

[0012] According to the braking system of the present disclosure, while the first braking device generates a braking force and a stop holding force in the vehicle while not receiving a suppression request from the control device, it enters a suppression state while receiving a suppression request from the control device. Further, while the vehicle is continuing autonomous driving, the control device outputs a suppression request to the first braking device. Thereby, while realizing the autonomous driving of the vehicle by the control device, when a defect or abnormality of the control device occurs, the first braking device generates a braking force and a stop holding force in the vehicle, and the vehicle can be braked without requiring a driver.

Brief Description of the Drawings

[0013]

Figure 1

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Figure 10

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, when referring to numbers such as the number of elements, quantity, amount, range, etc. in the embodiments shown below, unless otherwise specified or clearly specified by the principle, the ideas related to the present disclosure are not limited to the mentioned numbers. Also, the configurations and the like described in the embodiments shown below are not necessarily essential to the ideas related to the present disclosure, unless otherwise specified or clearly specified by the principle. In each figure, the same or corresponding parts are denoted by the same reference numerals, and the redundant descriptions are appropriately simplified or omitted.

[0015] 1. Autonomous Driving System The braking system according to the present embodiment is applied to an autonomous driving system in which a vehicle performs autonomous driving without requiring a driver in the vehicle. FIG. 1 is a block diagram for explaining an example of the configuration of an autonomous driving system 10 to which the braking system according to the present embodiment is applied. The autonomous driving system 10 includes an autonomous driving control device 100, a driving operation device 200, and a parking / emergency energy holding supply device 300.

[0016] The autonomous driving control device 100 is configured to be able to transmit information with the devices included in the driving operation device 200. Typically, it is electrically connected by a wire harness. However, it may be configured in other ways. For example, it may be configured to be able to transmit information by wireless communication or optical communication.

[0017] The autonomous driving control device 100 is a control device that executes control related to autonomous driving and outputs a control signal for performing autonomous driving. Typically, based on driving environment information indicating information about the driving environment of the vehicle and map information, a driving plan to the destination is set, and a driving trajectory on the driving route is generated. Then, in order for the vehicle to travel along the driving trajectory, control signals related to acceleration, steering, braking, and other driving operations related to autonomous driving (such as turning on the headlights, operating the direction indicator, turning on the hazard lights, operating the windshield wiper, operating the horn, etc.) are generated and output. Here, the driving environment information and map information are typically obtained via sensors and communication devices provided in the vehicle not shown in FIG. 1.

[0018] The autonomous driving control device 100 is an information processing device including a memory 110 and a processor 120. Typically, the autonomous driving control device 100 is an ECU (Electronic Control Unit). The memory 110 stores a program 111 executable by the processor 120 and data 112 including information obtained by the autonomous driving control device 100 and various information related to the program 111. The processor 120 reads the program 111 from the memory 110 and executes processing according to the program 111 based on the information of the data 112 read from the memory 110.

[0019] The autonomous driving control device 100 outputs a control signal via an input / output interface. The control signal output by the autonomous driving control device 100 is transmitted to the driving operation device 200.

[0020] The driving operation device 200 is a type of device that realizes the driving operation of a vehicle according to a control signal acquired from the autonomous driving control device 100. When the devices included in the driving operation device 200 operate according to the control signal output by the autonomous driving control device 100, the autonomous driving of the vehicle is realized. The driving operation device 200 includes an acceleration device 210, a steering device 220, and a braking device 230. Additionally, it may also include other driving operation devices 240. Here, the devices included in the driving operation device 200 are functionally classified, but each device may be integrally configured. For example, like an in-wheel motor, the acceleration device 210 and the braking device 230 may be integrally configured as one device.

[0021] The acceleration device 210 is a device that realizes the driving operation related to acceleration in forward and reverse. Typically, it is composed of a sensor that detects the state of an engine (internal combustion engine, electric motor, or their hybrid, etc.) and a transmission mechanism, an actuator that drives the engine and the transmission mechanism, and an ECU that controls the actuator. Then, according to the control signal acquired from the autonomous driving control device 100, the ECU controls the actuator, thereby realizing the driving operation related to the acceleration of autonomous driving.

[0022] The steering device 220 is a device that realizes the driving operation related to steering. Typically, it is composed of a sensor that detects the state of a steering mechanism provided in the vehicle, an actuator that drives the steering mechanism, and an ECU that controls the actuator. Then, according to the control signal acquired from the autonomous driving control device 100, the ECU controls the actuator, thereby realizing the driving operation related to the steering of autonomous driving.

[0023] The braking device 230 is a device that realizes the driving operation related to braking. Typically, it is composed of a sensor that detects the state of a braking mechanism provided in the vehicle, an actuator that drives the braking mechanism, and an ECU that controls the actuator. Then, according to the control signal acquired from the autonomous driving control device 100, the ECU controls the actuator, thereby realizing the driving operation related to the braking of autonomous driving.

[0024] In the automatic driving system 10 to which the braking system according to this embodiment is applied, as will be described later, the braking device 230 includes a first braking device and a second braking device. The first braking device and the second braking device will be described later.

[0025] The other driving operation device 240 is, for example, a device related to operations such as headlights, turn indicators, hazard lights, wipers, and horns.

[0026] The parking / emergency energy holding and supply device 300 is a device that holds energy required when the vehicle stops such as during parking or in an emergency and supplies it as needed. Typically, it is a hydraulic accumulator, a storage battery, a spring, a latch mechanism, etc.

[0027] 2. Braking System Hereinafter, the braking system according to this embodiment will be described as applied to the automatic driving system 10 shown in FIG. 1.

[0028] 2-1. Configuration FIG. 2 is a block diagram for explaining the configuration of the braking system 20 according to this embodiment. (A) of FIG. 2 shows the case where the vehicle is continuously performing autonomous driving by the autonomous driving control device 100 (during continuous autonomous driving), and (B) of FIG. 2 shows the case where autonomous driving has ended (during end of autonomous driving). Here, the case where autonomous driving has ended means the case where the autonomous driving of the vehicle by the autonomous driving control device 100 is not being performed, including when the vehicle has not been started, when the vehicle has ended autonomous driving (the vehicle has stopped due to power off or engine off) (hereinafter, also referred to as the "end state"), between when the vehicle starts and starts autonomous driving, when the vehicle is parked, when the vehicle has ended autonomous driving and is temporarily stopped (for example, stopped at a parking position), after the start of the autonomous driving control device 100 has ended, etc.

[0029] The braking system 20 includes an autonomous driving control device 100, a first braking device 231, and a second braking device 232. Here, the first braking device 231 and the second braking device 232 are devices included in the braking device 230.

[0030] While the first braking device 231 has not received a suppression request from the autonomous driving control device 100, it generates braking force and stop holding force for the vehicle (braking state). On the other hand, while receiving a suppression request from the autonomous driving control device 100, it operates so as to be in a state where it does not generate braking force and stop holding force for the vehicle (suppression state). Here, the stop holding force is a force for maintaining the state where the vehicle stops without moving on a slope or the like. Details of the suppression request will be described later.

[0031] Note that while the first braking device 231 has not received a suppression request from the autonomous driving control device 100, it does not require external energy supply when generating braking force and stop holding force. That is, even if the external energy supply is interrupted, it can generate the required braking force and maintain stop holding.

[0032] For example, the first braking device 231 is in a state where the vehicle wheels are pressed by brake pads, brake shoes, etc., and also includes an actuator for operating the brake pads, brake shoes, etc. And while receiving a suppression request from the autonomous driving control device 100, the actuator is operated so that the brake pads, brake shoes, etc. release the wheels.

[0033] In this case, while the first braking device 231 has not received a suppression request from the autonomous driving control device 100, the state where the vehicle wheels are pressed by brake pads, brake shoes, etc. is maintained, so that braking force and stop holding force are generated. While receiving a suppression request from the autonomous driving control device 100, the brake pads, brake shoes, etc. release the wheels, resulting in a suppression state where braking force and stop holding force are not generated.

[0034] When the second braking device 232 receives a braking request from the autonomous driving control device 100, it operates to generate a braking force for the vehicle. The braking request given to the second braking device may include a control amount indicating the degree of braking. In this case, the second braking device operates the actuator according to the control amount to brake the vehicle.

[0035] The second braking device 232 is, for example, a device related to a braking mechanism using a typical disk brake or drum brake, and when it receives a braking request, it operates the actuator to press the vehicle wheels with brake pads or brake shoes to generate a braking force.

[0036] With reference to FIG. 2 below, a typical operation of the braking system 20 will be described.

[0037] First, with reference to FIG. 2(A), the operation of the braking system 20 when autonomous driving is in progress will be described. As shown in FIG. 2(A), while autonomous driving is in progress, the autonomous driving control device 100 executes a process of outputting a suppression request to the first braking device 231 as a control signal. That is, while autonomous driving is in progress, the first braking device 231 is in a suppressed state and does not generate a braking force and a stop holding force.

[0038] On the other hand, while autonomous driving is in progress and braking is required in autonomous driving (for example, when the preceding vehicle decelerates, stops temporarily, etc.), the autonomous driving control device 100 executes a process of outputting a braking request to the second braking device 232 as a control signal. Thereby, when braking is required in autonomous driving, the second braking device 232 generates a braking force, and thus the driving operation related to braking can be realized (dashed-dotted line).

[0039] Next, referring to FIG. 2(B), the operation of the braking system 20 when autonomous driving has ended will be described. As shown in FIG. 2(B), when autonomous driving has ended, the autonomous driving control device 100 will stop its output. Therefore, the first braking device 231 enters a braking state without receiving a suppression request, and generates a braking force and a stop holding force. As a result, it is possible to achieve the stop and stop holding of the vehicle when autonomous driving has ended. On the other hand, since the second braking device 232 does not receive a braking request, it does not generate a braking force.

[0040] Thus, in the automatic driving system 10 to which the braking system 20 is applied, during continuous autonomous driving, the driving operation related to braking is realized by the second braking device 232, and during the end of autonomous driving, the stop and stop holding of the vehicle are realized by the first braking device 231.

[0041] 2-2. Suppression Request As described above, during continuous autonomous driving, the autonomous driving control device 100 outputs a suppression request to the first braking device 231. And the first braking device 231 enters a suppression state and does not generate a braking force and a stop holding force while receiving the suppression request. Hereinafter, the suppression request will be described in more detail.

[0042] FIG. 3 is a conceptual diagram showing an example of the suppression request output by the autonomous driving control device 100. In the example shown in FIG. 3, the suppression request is a signal that turns on for a time d1, then turns off for a time d2, then turns on for a time d3, then turns off for a time d4, then turns on for a time d5, and then turns off for a time d6 every period dt. Thus, the suppression request is a signal that follows a rule of turning on and off in a predetermined pattern every predetermined period dt. However, the predetermined period dt and the predetermined pattern may be experimentally given optimally.

[0043] While the signal transmitted from the autonomous driving control device 100 turns on and off according to a predetermined period and pattern, the first braking device 231 determines that it is receiving a suppression request and enters a suppression state. On the other hand, when a signal that does not follow this predetermined rule is transmitted, the first braking device 231 determines that the signal is not a suppression request and enters a braking state. These determinations are typically executed by the ECU that constitutes the first braking device 231.

[0044] FIG. 4 is a conceptual diagram showing an example of a signal (output signal) output by the autonomous driving control device 100 and the state of the first braking device 231 with respect to that signal. Here, it is assumed that the suppression request is a signal that follows a predetermined rule equivalent to the example shown in FIG. 3. Also, in FIG. 4, two examples (A) and (B) are shown. Each example will be described below.

[0045] The example shown in FIG. 4(A) shows a case where the autonomous driving control device 100 outputs a signal that follows a predetermined rule for one cycle from time t1 and then stops the signal (solid line). In this case, the first braking device 231 determines that it is receiving a suppression request because the transmitted signal follows the predetermined rule from time t1 to time t2, and continues the suppression state. Then, at time t2, the signal transmitted is off while it should be on according to the predetermined rule (dashed line), and since it does not follow the predetermined rule, the first braking device 231 determines that it is not receiving a suppression request and enters a braking state.

[0046] The example shown in FIG. 4(B) shows a case where the autonomous driving control device 100 outputs a signal that follows a rule for two cycles from time t1 and then continues to output a signal that does not follow the rule as shown in FIG. 4(B) (solid line). This is, for example, a case where an output abnormality occurs in the autonomous driving control device 100 at time tx. In this case, the first braking device 231 determines that it is receiving a suppression request because the transmitted signal follows the predetermined rule from time t1 to time tx, and continues the suppression state. Then, at time tx, the signal transmitted is on while it should be off according to the predetermined rule (dashed line), and since it does not follow the predetermined rule, the first braking device 231 determines that it is not receiving a suppression request and enters a braking state.

[0047] Here, when it is determined that the suppression request is not received and the braking state is entered, the first braking device 231 may be configured to continue the braking state regardless of the signal transmitted until it is confirmed that no abnormality that hinders autonomous driving has occurred.

[0048] In this way, the first braking device 231 enters the braking state and generates a braking force and a stop holding force not only when the output of the autonomous driving control device 100 stops, but also when the output of the autonomous driving control device 100 becomes abnormal due to a failure or the like.

[0049] Note that in order to sufficiently maintain the responsiveness of the generation of the braking force and the stop holding force by the first braking device 231, it is desirable that the cycle dt be given sufficiently short.

[0050] 2-3. Operations when a failure or abnormality occurs in the autonomous driving control device Hereinafter, the operation of the braking system 20 when a failure or abnormality occurs in the autonomous driving control device 100 will be described.

[0051] FIG. 5 is a block diagram for explaining the operation of the braking system 20 when a failure or abnormality occurs in the autonomous driving control device 100.

[0052] First, referring to FIG. 5(A), the operation of the braking system 20 when the autonomous driving control device 100 fails (at the time of failure) will be described. As shown in FIG. 5(A), at the time of failure, the output of the autonomous driving control device 100 becomes fixed or stops. Therefore, the first braking device 231 determines that the suppression request is not received and enters the braking state, and generates a braking force and a stop holding force.

[0053] Next, referring to FIG. 5(B), the operation of the braking system 20 when an abnormality occurs in the autonomous driving control device 100 and the output becomes abnormal (at the time of abnormality) will be described. At this time, since the signal transmitted from the autonomous driving control device 100 does not follow the rule, the first braking device 231 determines that the suppression request is not received and enters the braking state, and generates a braking force and a stop holding force.

[0054] Thus, in the automatic driving system 10 to which the braking system 20 is applied, even when a failure or abnormality occurs in the autonomous driving control device 100, the first braking device 231 can generate a braking force and a stop holding force, and brake the vehicle without requiring a driver.

[0055] As described above, when generating the braking force and the stop holding force, the first braking device 231 does not require an external energy supply. Therefore, even if the energy supplied by the parking / emergency energy holding supply device 300 is interrupted and power is lost, the stop holding of the vehicle can be maintained.

[0056] Also, as will be described later, when an abnormality that hinders autonomous driving occurs in the vehicle and a predetermined abnormality process is executed, the first braking device 231 may operate to generate a braking force and a stop holding force regardless of a suppression request. Thereby, even when an abnormality other than the output abnormality of the autonomous driving control device 100 occurs during the autonomous driving, the vehicle can be braked without requiring a driver.

[0057] 2-4. Supplementary As described above, in the automatic driving system 10 to which the braking system 20 is applied, during the autonomous driving, the driving operation related to braking is realized by the second braking device 232, and during the end of the autonomous driving, the first braking device 231 realizes the stop and stop holding of the vehicle. Also, when a failure or abnormality occurs in the autonomous driving control device 100, the first braking device 231 generates a braking force and a stop holding force to brake the vehicle.

[0058] That is, the first braking device 231 typically functions as a parking or emergency braking device. On the other hand, the second braking device 232 typically functions as the main braking device while the vehicle is in motion. Note that the first braking device 231 and the second braking device 232 may be categories including a plurality of devices. For example, the first braking device 231 may separately include a device that functions as a parking braking device and a device that functions as an emergency braking device. Further, the second braking device 232 may include, separately from the device that functions as the main braking device, a device that functions as a parking braking device and a device that functions as an emergency braking device, thereby constituting a redundant multi-system safety mechanism.

[0059] 3. Vehicle operation Hereinafter, the operation of the vehicle by the automatic driving system 10 to which the braking system 20 according to the present embodiment is applied will be described.

[0060] 3-1. Vehicle startup FIG. 6 is a flowchart showing an example of the vehicle startup process. The flowchart shown in FIG. 6 starts when the vehicle starts from the end state. Typically, it starts when the vehicle or a startup device provided outside the vehicle is operated when the vehicle is in the end state.

[0061] In step S100, the vehicle power is turned on. After step S100, the process proceeds to step S110.

[0062] In step S110, vehicle authentication is performed and a check of the authentication is carried out. Vehicle authentication is performed, for example, when a vehicle occupant operates an authentication device provided in the vehicle. Alternatively, it is performed when a vehicle operator operates a part of the vehicle or an external authentication device.

[0063] If the vehicle authentication in step S110 is successfully completed (step S120; Yes), the process proceeds to step S130. If the vehicle authentication in step S110 is not successfully completed (step S120; No), it is determined that an authentication abnormality has occurred in the vehicle, and the process proceeds to abnormality processing (step S500). The abnormality processing will be described later.

[0064] Note that the determination that the vehicle authentication is not correctly completed may be the case where the vehicle authentication check in step S110 is not completed within a predetermined number of times or within a predetermined time.

[0065] In step S130, pre-start processing of the driving operation device 200 is performed. Thereby, it is confirmed whether the driving operation device 200 can be started normally. Typically, the state of the devices connected to each device and the update of the software of each device are confirmed. This may be performed in each device, or may be performed in any one or more devices provided in the vehicle.

[0066] After step S130, if the driving operation device 200 can be started normally (step S140; Yes), the process proceeds to step S150. If the driving operation device 200 cannot be started normally (step S140; No), the process shifts to abnormal processing (step S500) assuming that an abnormality that hinders the driving operation of the vehicle has occurred.

[0067] In step S150, the driving operation device 200 is started. At this time, typically, the setting values such as control parameters in the ECU related to the driving operation device 200 are read, the sensors for detecting the state of the brake mechanism and the sensor data are checked, and self-diagnosis is performed by the diagnostic function. Here, it is determined whether the driving operation device 200 is normal by the diagnostic function of the driving operation device 200, the diagnostic device provided in the vehicle, or a combination thereof.

[0068] After step S150, if the driving operation device 200 is normal (step S160; Yes), the process proceeds to step S170. If the driving operation device 200 is not normal (step S160; No), the process shifts to abnormal processing (step S500) assuming that an abnormality that hinders the driving operation device 200 of the vehicle has occurred.

[0069] In step S170, the autonomous driving control device 100 is activated. At this time, typically, setting values such as control parameters are read, sensors related to autonomous driving and sensor data are checked, and self-diagnosis is performed by a diagnostic function. Here, it is determined whether the autonomous driving control device 100 is normal by the diagnostic function of the autonomous driving control device 100, a diagnostic device provided in the vehicle, or a combination thereof.

[0070] After step S170, if the autonomous driving control device 100 is normal (step S180; Yes), the startup process is terminated. If the autonomous driving control device 100 is not normal (step S180; No), it is considered that an abnormality has occurred in the autonomous driving control device 100, and the process proceeds to abnormality processing (step S500).

[0071] Note that the mounted devices other than the driving operation device 200 and the autonomous driving control device 100 are omitted in the flowchart shown in FIG. 6. However, those mounted devices may be configured to appropriately perform startup and determination of whether they are normal, similar to the driving operation device 200 and the autonomous driving control device 100.

[0072] Also, the first braking device 231 has not received a suppression request from the autonomous driving control device 100 until the vehicle starts autonomous driving. That is, when the vehicle is in the end state, the first braking device 231 is in the braking state, generating braking force and stop holding force for the vehicle. Thereby, the stop and stop holding of the vehicle are realized even when the vehicle is in the end state and during the period from the startup of the vehicle until the start of autonomous driving.

[0073] 3-2. Start of Autonomous Driving FIG. 7 is a flowchart showing an example of the operation of the vehicle when the vehicle starts autonomous driving. The flowchart shown in FIG. 7 is typically started while the vehicle is stopped. For example, while waiting for the start of autonomous driving after the vehicle is started, while the vehicle is parked, while autonomous driving is temporarily paused, and so on.

[0074] In step S200, by executing control related to autonomous driving by the autonomous driving control device 100, the vehicle starts autonomous driving. At this time, typically, as pre-start processing, the autonomous driving control device 100 checks the environment around the current position of the vehicle, acquires road traffic information, generates a driving plan, and so on.

[0075] After step S200, it is determined whether the transition to autonomous driving has been performed normally. For example, it is determined based on whether the vehicle is running according to the control signal, whether the driving operation device 200 is operating according to the control signal, and so on. When the transition to autonomous driving has been performed normally (step S210; Yes), autonomous driving is continued (step S220). When the transition to autonomous driving has not been performed normally (step S210; No), it is considered that an abnormality has occurred in the transition to autonomous driving, and the process proceeds to the abnormality processing (step S500).

[0076] During the continuation of autonomous driving (step S220), it is determined whether the autonomous driving control device 100 is normal at predetermined intervals (step S221). This is performed by the diagnostic function of the autonomous driving control device 100, a diagnostic device provided in the vehicle, or a combination thereof. When the autonomous driving control device 100 is normal (step S221; Yes), autonomous driving is continued. When the autonomous driving control device 100 is not normal (step S221; No), it is considered that an abnormality has occurred in the autonomous driving control device 100, and the process proceeds to the abnormality processing (step S500).

[0077] Note that from the start of autonomous driving (step S200) to the continuation of autonomous driving (step S220), the autonomous driving control device 100 outputs a suppression request to the first braking device 231. That is, from the start of autonomous driving (step S200) to the continuation of autonomous driving (step S220), the first braking device 231 is in a suppressed state and does not generate braking force and stop holding force for the vehicle. On the other hand, when braking of the vehicle is required during the continuation of autonomous driving (step S220), the autonomous driving control device 100 outputs a braking request to the second braking device 232. Thereby, the start and continuation of autonomous driving and braking in autonomous driving are realized.

[0078] Also, before the flowchart shown in FIG. 7 is started, since the vehicle is not in the state of starting autonomous driving, the first braking device 231 is in the braking state, and is generating braking force and stop holding force for the vehicle.

[0079] 3-3. End of Autonomous Driving FIG. 8 is a flowchart showing an example of the operation of the vehicle when the vehicle ends autonomous driving. The flowchart shown in FIG. 8 is started when the vehicle is continuing autonomous driving and the vehicle is to be stopped at a predetermined position. For example, it is started when the vehicle is to be stopped at the destination in the travel plan, when the vehicle is to be parked, when autonomous driving is to be temporarily suspended, etc.

[0080] In step S300, the autonomous driving control device 100 starts a vehicle stop process for stopping the vehicle at a predetermined position.

[0081] After step S300, it is determined whether the transition to the stop process has been normally performed. If the transition to the stop process has been normally performed (step S310; Yes), the stop process is continued (step S320). If the transition to the stop process has not been normally performed (step S310; No), it is considered that an abnormality has occurred in the transition to the stop process, and the process proceeds to an abnormality process (step S500).

[0082] While the stop process is continuing (step S320), it is determined whether the autonomous driving control device 100 is normal at each predetermined cycle (step S321). If the autonomous driving control device 100 is normal (step S321; Yes), the stop process is continued. If the autonomous driving control device 100 is not normal (step S321; No), it is considered that an abnormality has occurred in the autonomous driving control device 100 during the stop process, and the process proceeds to an abnormality process (step S500).

[0083] After the vehicle stop is completed by the stop process (step S322; Yes), autonomous driving is ended (step S330).

[0084] While the stop process is ongoing (step S320), the autonomous driving control device 100 outputs a suppression request to the first braking device 231. That is, while the stop process is ongoing (step S320), the first braking device 231 is in a suppressed state and does not generate braking force and stop holding force for the vehicle.

[0085] Also, after the autonomous driving is terminated (step S330), the output of the suppression request from the autonomous driving control device 100 to the first braking device 231 stops. That is, after the autonomous driving is terminated (step S330), the first braking device 231 is in a braking state and generates braking force and stop holding force for the vehicle. Thereby, after the termination of the autonomous driving, the stop and stop holding of the vehicle are realized.

[0086] Note that when starting the autonomous driving again after the autonomous driving is terminated (step S330) (for example, when starting the autonomous driving from a state of being stopped at a parking position, when resuming from a temporary pause of the autonomous driving, etc.), the flowchart shown in FIG. 7 is started again. In this case, the autonomous driving control device 100 may remain in an activated state (for example, standby state in an energy-saving mode). However, as described above, after the autonomous driving is terminated (step S330), the output of the suppression request from the autonomous driving control device 100 to the first braking device 231 may stop during the period until the autonomous driving is started again. In this case, the first braking device 231 is in a braking state.

[0087] 3-4. Completion of Vehicle Startup FIG. 9 is a flowchart showing an example of a vehicle startup completion process. The flowchart shown in FIG. 9 typically starts when the use of the vehicle is completed, such as when the vehicle reaches the destination after the termination of the autonomous driving. Alternatively, it starts when an operation to end the startup of the vehicle is performed on the vehicle or a startup device provided outside the vehicle after the termination of the autonomous driving.

[0088] In step S400, it is determined whether the autonomous driving control device 100 is normal. If the autonomous driving control device 100 is normal (step S400; Yes), the process proceeds to step S410. If the autonomous driving control device 100 is not normal (step S400; No), it is considered that an abnormality has occurred in the autonomous driving control device 100, and the process shifts to the abnormality handling (step S500).

[0089] In step S410, it is determined whether the vehicle is stopped. Typically, it is determined based on the driving environment information. If the vehicle is stopped (step S410; Yes), the process proceeds to step S420. If the vehicle is not stopped (step S410; No), it is considered that an abnormality has occurred in the vehicle stop determination, and the process shifts to the abnormality handling (step S500).

[0090] In step S420, the operation of starting the driving operation device 200 is terminated.

[0091] After step S420, the power supply of the vehicle is turned off (step S430).

[0092] Note that even after the operation of starting the driving operation device 200 (step S420) is terminated, the first braking device 231 is in the braking state, and generates braking force and stop holding force for the vehicle. Thereby, even after the operation of starting the driving operation device 200 is terminated, the stop and stop holding of the vehicle are realized.

[0093] 3 - 5. Abnormality Handling FIG. 10 is a flowchart showing the abnormality handling. The flowchart shown in FIG. 10 starts when an abnormality that hinders autonomous driving occurs in the vehicle as described above and the process shifts to the abnormality handling (step S500).

[0094] After shifting to the abnormality processing, a predetermined process is executed (step S510). For example, a process of stopping the vehicle according to a predetermined process, a process of storing sensor data such as the vehicle state in the memory of each ECU by a diagnosis function, a process of notifying the occurrence of an abnormality (by sound, display, etc.), and the like are executed. Here, different processes may be executed according to the content of the abnormality.

[0095] After executing the predetermined process (step S510), regardless of whether the autonomous driving control device 100 outputs a suppression request, the first braking device 231 is not put into a suppression state (step S520). That is, the first braking device 231 generates a braking force and a stop holding force for the vehicle regardless of the suppression request. This is performed, for example, by the ECU related to the first braking device 231 executing a process of ignoring the suppression request upon receiving the execution of the abnormality processing. Alternatively, it may be performed by cutting off the transmission of information from the autonomous driving control device 100 to the first braking device 231 or by ending the activation of the ECU related to the first braking device 231. Thereby, the first braking device 231 is in a braking state, and the vehicle is stopped and held in a stopped state.

[0096] By executing such abnormality processing, when the vehicle authentication is not correctly completed, when the operation device 200 cannot be normally activated, when the autonomous driving control device 100 is not normal, when the transition to autonomous driving is not normally performed, when the transition to the stop processing is not normally performed, when the vehicle is not stopped in the end process, in the case where an abnormality that hinders autonomous driving has occurred in the vehicle, the first braking device 231 can stop and hold the vehicle.

[0097] Note that the abnormality processing may be executed even when the braking device 230 is not normal. In this case, when the first braking device 231 is not normal, the second braking device 232 may be configured to perform braking.

[0098] After the abnormal processing, if there is no failure or the like in the driving operation device 200, typically, the vehicle is stopped by the first braking device 231 until autonomous driving is started (start of the operation of the vehicle shown in FIG. 4).

[0099] Note that the processing related to the abnormal processing may be appropriately executed in each device provided in the vehicle, or may be performed in any one or a plurality of devices provided in the vehicle. Further, in preparation for an abnormal state that is not detected for some reason during autonomous driving, even when the autonomous driving control device 100 is operating normally, an emergency stop means (for example, an emergency stop button, a bumper switch, a touch sensor, etc.) capable of stopping the vehicle during autonomous driving from the outside may be provided. And when the abnormal processing is not performed for some reason, the first braking device may be brought into a braking state by the emergency stop means.

[0100] 4. Effects As described above, the braking system 20 according to the present embodiment includes a first braking device 231. The first braking device 231 is in a braking state while not receiving a suppression request from the autonomous driving control device 100, and is in a suppression state while receiving a suppression request from the autonomous driving control device 100. The autonomous driving control device 100 outputs a suppression request to the first braking device 231 while the vehicle is continuously autonomously driving. Thereby, while realizing the autonomous driving of the vehicle by the autonomous driving control device 100, even when a failure or abnormality occurs in the autonomous driving control device 100, the first braking device 231 generates a braking force and a stop holding force, and the vehicle can be braked without requiring a driver.

[0101] Further, the first braking device 231 does not require an external energy supply when generating a braking force and a stop holding force while not receiving a suppression request from the autonomous driving control device 100. Thereby, even after the power is lost, such as before the vehicle starts or when the energy supplied by the parking / emergency energy holding supply device 300 is interrupted, the vehicle can be stopped and the stop can be held.

[0102] Further, the suppression requirement is a signal that turns on and off in a predetermined pattern every predetermined period dt, and the first braking device 231 does not regard the signal as a suppression requirement when the signal transmitted from the autonomous driving control device 100 does not follow the rule. Thereby, when the output of the autonomous driving control device 100 is abnormal, the first braking device 231 can generate a braking force and a stop holding force, and brake the vehicle without requiring the driver.

[0103] Also, the braking system 20 according to the present embodiment includes a second braking device 232. The second braking device operates to generate a braking force on the vehicle when it receives a braking request from the autonomous driving control device 100. And the autonomous driving control device 100 outputs a braking request to the second braking device when braking is required during autonomous driving. Thereby, braking during autonomous driving can be realized.

[0104] Furthermore, in the abnormal processing, the braking system 20 according to the present embodiment does not put the first braking device in a suppressed state. Thereby, when an abnormality that hinders autonomous driving occurs in the vehicle, the first braking device 231 can stop and hold the vehicle. Also, when the abnormal processing is not performed for some reason, the first braking device can be configured to be in a braking state by interposing an emergency stop means that can be operated from outside the vehicle during autonomous driving.

Explanation of Reference Numerals

[0105] 10 Automatic driving system 20 Braking system 100 Autonomous driving control device 200 Driving operation device 210 Accelerator device 220 Steering device 230 Braking device 231 First braking device 232 Second braking device 240 Other driving operation devices 300 Parking / emergency energy holding and supply device

Claims

1. A braking system for a vehicle that performs autonomous driving, comprising: a control device that executes control related to the autonomous driving; a first braking device that, while not receiving a suppression request from the control device, generates a braking force and a stop holding force for the vehicle, and enters a suppression state in which the braking force and the stop holding force are not generated for the vehicle while receiving the suppression request from the control device; and the control device executes a process of outputting the suppression request to the first braking device while the autonomous driving of the vehicle continues; the suppression request is a signal that follows a rule of turning on and off in a predetermined pattern at predetermined intervals; the first braking device does not regard the signal received from the control device as the suppression request when the signal does not follow the rule. A braking system characterized by the above.

2. The braking system according to Claim 1, further comprising: a second braking device that, when receiving a braking request from the control device, operates to generate a braking force for the vehicle; the control device executes a process of outputting the braking request to the second braking device when braking is required in the autonomous driving. A braking system characterized by the above.

3. The braking system according to Claim 1 or 2, wherein when it is assumed that an abnormality that hinders the autonomous driving has occurred in the vehicle, the first braking device generates the braking force and the stop holding force for the vehicle regardless of the suppression request. A braking system characterized by the above.

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