Autonomous Vehicles

Abstract

To provide an automatic driving vehicle which can safely and surely stop when an abnormality occurs in an operation of a control unit and / or a power source.SOLUTION: An automatic driving vehicle 10 comprises: a drive control unit 14 for a travel unit 11, a steering unit 12 and a brake unit 13; a detection unit 19 for a travel state; a control unit 17 which generates a travel command with a detection signal of the detection unit; a travel control unit 15 which generates a travel signal in response to the travel command and transmits the travel signal to the drive control unit; an emergency brake unit 20 which performs emergency braking on the brake unit; a backup control unit 18 which complements the control unit; and an operation monitoring unit 16 which monitors the operations of the control unit and the backup control unit. The control unit and the backup control unit mutually monitor the operations all the time. When the backup control unit detects an abnormality in the control unit, the backup control unit, instead of the control unit, generates and transmits a stop command 18c to the travel control unit, the travel control unit generates and transmits a stop signal 15b to the drive control unit, and the drive control unit performs driving control on the travel unit, the steering unit and the brake unit so as to stop the vehicle.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an autonomous vehicle equipped with an emergency braking unit for performing emergency braking in the event of an emergency, for example. [Background technology]

[0002] Generally, in an autonomous vehicle, a main autonomous driving control unit (in this application, the "autonomous driving control unit" is simply referred to as a "control unit" and is used to distinguish it from a driving control unit, backup control unit, drive control unit, etc.) that controls the driving of the autonomous vehicle based on detection signals from a detection unit consisting of a position sensor, vehicle speed sensor, three-axis acceleration sensor, obstacle sensor, etc. that detects the driving state generates driving commands, the driving control unit generates driving signals based on the driving commands, and the drive control unit drives and controls the driving units, steering unit, and braking unit based on the driving signals, thereby performing autonomous driving.

[0003] Furthermore, there are also known autonomous vehicles equipped with an emergency braking unit. In such autonomous vehicles, when the control unit detects an emergency based on a detection signal from the detection unit, it generates an emergency stop command, and the emergency braking unit drives the braking unit in response to this emergency stop command, thereby bringing the autonomous vehicle to an emergency stop.

[0004] In addition, conventionally, a brake structure using fluid pressure to brake the wheels by operating an operating member such as a brake pedal arranged in front of the driver's seat has been known, and for example, Patent Document 1 discloses a vehicle braking device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-067320 Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional self-driving vehicles, when an emergency occurs, the control unit detects the emergency and controls the emergency braking unit, which then brings the self-driving vehicle to an emergency stop. However, if an abnormal operation occurs in the control unit, the self-driving vehicle will no longer be able to operate normally.

[0007] In contrast to this, the brake structure of Patent Document 1 is designed to enable braking operation by operating the brake on the operation input unit of the braking unit even in the event of an abnormality. However, if, for example, an abnormal operation occurs in the control unit or power is no longer supplied, it is difficult to control the driving of the braking unit.

[0008] In view of the above, the present invention aims to provide an autonomous vehicle that can be safely and reliably stopped when an abnormality occurs in the operation of the control unit or the power supply using a simple configuration. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides an autonomous vehicle comprising a driving unit, a steering unit, and a braking unit; a drive control unit that drives and controls the driving unit, the steering unit, and the braking unit; a detection unit consisting of sensors including a position sensor that detects the driving state, a vehicle speed sensor, a three-axis acceleration sensor, and an ambient sensor; a control unit that generates a driving command based on a detection signal from the detection unit; a driving control unit that generates a driving signal based on the driving command from the control unit and sends it to the drive control unit; and an emergency braking unit that mechanically drives the brake unit to perform emergency braking, wherein, in the event of an abnormality, the driving control unit drives and controls the emergency braking unit to perform emergency braking, and further comprises a backup control unit that complements the control unit, and a monitoring unit that monitors the operation of the control unit and the backup control unit. and an operation monitoring unit that monitors the operation of the backup control unit and the control unit, wherein the control unit and the backup control unit constantly monitor each other's operations, and when the control unit detects abnormal operation of the backup control unit, it generates a stop command and sends this stop control command to the traveling control unit via the operation monitoring unit, and when the backup control unit detects abnormal operation of the control unit, it switches to a backup mode, generates a stop command on behalf of the control unit, and sends this stop command to the traveling control unit via the operation monitoring unit, and when the traveling control unit receives the stop command, it generates a stop signal and sends it to the drive control unit, and when the drive control unit receives the stop signal, it drives and controls the traveling unit, steering unit, and braking unit to stop the vehicle.

[0010] The operation monitoring unit preferably always monitors the operation of the control unit and the backup control unit, and when the operation monitoring unit detects abnormal operation of both the control unit and the backup control unit, switches to an error mode and generates an emergency stop command without relying on a travel command from the control unit or the backup control unit, and sends it to the travel control unit or the emergency braking unit. The emergency braking unit preferably always monitors the operation of the operation monitoring unit and the power supplies supplied to the control unit, backup control unit, operation monitoring unit, travel control unit, and drive control unit, and when the emergency braking unit detects abnormal operation of the travel control unit or an abnormality in the power supply, activates the braking unit to bring the vehicle to an emergency stop by emergency braking. The backup control unit has the same functions as the control unit, or has the same degenerate driving function as the control unit, or has only a braking function for stopping the vehicle. The drive control unit preferably slows down the vehicle or pulls over to the shoulder of the road and stops it based on a stop command from the backup control unit. The emergency braking unit preferably comprises an emergency driving source that releases driving force when an emergency occurs, and an emergency operating unit that moves an operation input unit for braking operation of the braking unit forward and backward using the driving force from the emergency driving source. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an autonomous vehicle that can be safely and reliably stopped with a simple configuration when an abnormality occurs in the operation of the control unit or in the power supply. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing the overall configuration of an autonomously driven vehicle according to the present invention. [Figure 2] FIG. 2 is a block diagram showing a control system for the autonomously driven vehicle of FIG. 1. [Figure 3] 2 is a block diagram schematically illustrating a braking unit and an emergency braking unit in the autonomously driven vehicle of FIG. 1. FIG. [Figure 4] FIG. 4 is a layout diagram schematically showing the layout of the braking unit and emergency braking unit shown in FIG. 3. [Figure 5] 4 is a flowchart showing an operation when an abnormal operation occurs in a control unit in the automatically driven vehicle of FIG. 1. [Figure 6] 4 is a flowchart showing an operation when an abnormal operation occurs in both a control unit and a backup control unit in the automatically driven vehicle of FIG. 1. [Figure 7] 10 is a flowchart showing the operation of the operation monitoring unit in the automatically driven vehicle of FIG. 1 when an abnormality occurs. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, the present invention will be described in detail based on the embodiments shown in the drawings. 1 and 2 show the overall configuration and control system of one embodiment of an autonomously driven vehicle 10 according to the present invention. As shown in Fig. 1, the autonomously driven vehicle 10 is composed of a driving unit 11, a steering unit 12, a braking unit 13, a drive control unit 14 that drives and controls the driving unit 11, the steering unit 12, and the braking unit 13, a driving control unit 15, an operation monitoring unit 16, a control unit 17, a backup control unit 18, and a detection unit 19. The drive control unit 14, the driving control unit 15, the operation monitoring unit 16, the control unit 17, the backup control unit 18, the sensors of the detection unit 19, and the emergency braking unit 20 are interconnected by a so-called in-vehicle LAN (CAN).

[0014] Although not shown, the traveling unit 11 is composed of, for example, four wheels and a drive source that drives the front and / or rear wheels of the four wheels as drive wheels. This drive source is composed of an engine such as a gasoline engine or a diesel engine, or a drive motor. The steering unit 12 can steer, for example, the front wheels of the four wheels, and swing them left and right to make the autonomously driven vehicle 10 travel straight or turn left or right. Note that the drive wheels and steered wheels may be the same wheels.

[0015] Braking unit 13 is configured with a known brake structure that stops the rotation of at least only the front wheels, only the rear wheels, or all of the four wheels, as will be described later. The drive source of traveling unit 11, steering unit 12, and steering unit 13 are each drive-controlled by drive control unit 14, so that the drive wheels are driven to rotate and the steering wheels are swung left and right, or braking unit 13 stops the rotation of the wheels, allowing autonomous vehicle 10 to travel forward, backward, or turn left and right in a predetermined direction and stop.

[0016] The drive control unit 14 controls the drive source of the driving unit 11, the steering unit 12, and the braking unit 13 based on a driving signal 15a from the driving control unit 15, and drives or brakes the corresponding drive wheels to drive or stop the vehicle at the speed, forward, backward, left or right turn, etc. set by the driving signal 15a. The drive control unit 14 has the functions of controlling driving, steering, and braking, that is, stepping on the accelerator, stepping on the brake, turning the steering wheel, etc.

[0017] The driving control unit 15 generates a driving signal 15a based on a driving command 17a input from the control unit 17 via the operation monitoring unit 16, and sends the signal to the drive control unit 14. Furthermore, the driving control unit 15 generates a stop signal 15b, for example, to quickly slow down and pull over to the shoulder to stop, and sends the signal to the drive control unit 14 based on an emergency stop command 17b or a stop command 17c from the control unit 17, or an emergency stop command 18b or a stop command 18c from the backup control unit 18. The driving signal 15a may be a signal including a driving program. Note that driving such as quickly slowing down the autonomous vehicle 10 and pulling over to the shoulder to stop is called degenerate driving.

[0018] When stop command 17c from control unit 17 is degenerate driving, drive control unit 14 drives and controls driving unit 11, steering unit 12, and braking unit 13 based on stop signal 15b due to degenerate driving from driving control unit 15, causing autonomous vehicle 10 to quickly slow down and pull over to the shoulder of the road to stop. Here, driving signal 15a is created to specify the driving speed, steering angle, acceleration, and deceleration when autonomous vehicle 10 drives along a driving route from the departure point to the destination, and drive control unit 14 drives and controls driving unit 11, steering unit 12, and braking unit 13 in accordance with this driving signal 15a, allowing autonomous vehicle 10 to drive at a specified driving speed along the driving route from the departure point to the destination.

[0019] Furthermore, driving control unit 15 includes emergency braking unit 20. When emergency braking unit 20 receives emergency stop signal 15c from driving control unit 15, or when emergency stop commands 17b, 18b are received from control unit 17 or backup control unit 18 via operation monitoring unit 16 as described below, emergency braking unit 20 drives brake unit 13 with emergency stop signal 20a to perform emergency braking and bring autonomously driven vehicle 10 to an emergency stop. Furthermore, emergency braking unit 20 constantly monitors the operation of operation monitoring unit 16, and when an abnormal operation occurs in operation monitoring unit 16, emergency braking unit 20 immediately activates brake unit 13 with emergency stop signal 20a to perform emergency braking and bring autonomously driven vehicle 10 to an emergency stop. Furthermore, as described below, when an abnormality occurs in the power supply of autonomously driven vehicle 10, for example, when the power supply is stopped, emergency braking unit 20 similarly immediately activates brake unit 13 with emergency stop signal 20a to perform emergency braking and bring autonomously driven vehicle 10 to an emergency stop.

[0020] 2, operation monitoring unit 16 receives a traveling command 17a, an emergency stop command 17b, and a stop command 17c from control unit 17, as well as a traveling command 18a, an emergency stop command 18b, and a stop command 18c from backup control unit 18. After receiving a notification of backup mode from backup control unit 18, operation monitoring unit 16 ignores various commands from control unit 17 and performs subsequent operations in accordance with stop command 18c from backup control unit 18. Operation monitoring unit 16 constantly monitors the operations of control unit 17 and backup control unit 18, and when both are operating normally, sends traveling command 17a, emergency stop command 17b, and stop command 17c from control unit 17 to traveling control unit 15.

[0021] On the other hand, if operation monitoring unit 16 detects abnormal operation of both control unit 17 and backup control unit 18, it switches to an error mode and generates and sends emergency stop command 16a to driving control unit 15 without relying on driving commands 17a and 18a from control unit 17 and backup control unit 18. In response to this, driving control unit 15 generates emergency stop signal 15c based on emergency stop command 16a and sends it to drive control unit 14. As a result, drive control unit 14 drives brake unit 13 to perform emergency braking and brings autonomously driven vehicle 10 to an emergency stop. In this case, operation monitoring unit 16 may send emergency stop command 16a directly to emergency braking unit 20. As a result, emergency braking unit 20 drives brake unit 13 to perform emergency braking and brings autonomously driven vehicle 10 to an emergency stop.

[0022] The control unit 17, which is comprised of, for example, a personal computer, generates a driving command 17a while referring to various detection signals 19a input from the detection unit 19 and sends it to the driving control unit 15 via the operation monitoring unit 16. The control unit 17 references the various detection signals 19a and, when it detects an emergency, generates an emergency stop command 17b and sends it to the driving control unit 15 via the operation monitoring unit 16. The control unit 17 also constantly monitors the operation of the backup control unit 18. When it detects abnormal operation of the backup control unit 18, it generates a stop command 17c and sends it to the operation monitoring unit 16. The driving command 17a, emergency stop command 17b, and stop command 17c from the control unit 17 encompass all normal automatic driving functions, as well as functions such as avoidance and pulling over to the side of the road to ensure safety in the event of an abnormality, and on-the-spot stopping such as an emergency stop. In this specification, the functions of the control unit 17 refer to all functions related to automatic driving, including normal driving, avoidance in the event of an abnormality, and emergency stopping.

[0023] The backup control unit 18 is connected to the control unit 17 via a wired line or an appropriate wireless line such as Wi-Fi, and has control functions similar to those of the control unit 17 or some functions, including a braking function, that are subordinate to the control unit 17. The braking function subordinate to the control unit 17 means that the backup control unit 18 has some of the functions related to autonomous driving that the control unit 17 has. For example, the backup control unit 18 may have only a degenerate driving or braking function. The backup control unit 18 creates a driving command 18a while referring to various detection signals 19a input from the detection unit 19, and sends it to the driving control unit 15 via the operation monitoring unit 16. The backup control unit 18 then creates an emergency stop command 18b and sends it to the driving control unit 15 via the operation monitoring unit 16, upon detecting the occurrence of an emergency, by referring to the various detection signals 19a. Furthermore, backup control unit 18 constantly monitors the operation of control unit 17, and when it detects abnormal operation of control unit 17, it switches to backup mode, notifies operation monitoring unit 16 of this, and generates and sends stop command 18c to operation monitoring unit 16. In response to this, operation monitoring unit 16 ignores the command from control unit 17 in backup mode, and sends stop command 18c from backup control unit 18 to driving control unit 15.

[0024] Backup control unit 18 may have the same functions as control unit 17. In this case, when an operational abnormality occurs in control unit 17, backup control unit 18 controls driving control unit 15 in place of control unit 17 in backup mode, and can perform control equivalent to that of control unit 17 when driving drive control unit 14.

[0025] Backup control unit 18 may have a braking function that is lower in level than control unit 17. When an operational abnormality occurs in control unit 17, backup control unit 18 controls driving control unit 15 in place of control unit 17 in backup mode, and when driving drive control unit 14, it is possible to control functions of control unit 17, including some of the braking functions, thereby reliably stopping autonomous vehicle 10. In this case, backup control unit 18 may have a simpler configuration than control unit 17, and the cost of backup control unit 18 can be reduced.

[0026] The detection unit 19 is composed of sensors including, for example, a position sensor, a vehicle speed sensor, a three-axis acceleration sensor, and an ambient sensor to detect the driving state of the autonomously driven vehicle 10, and sends detection signals 19a from each of these sensors to the control unit 17 and the backup control unit 18. The position sensor detects the longitude and latitude using a GNSS sensor, for example, a GPS sensor, and detects the current geodetic data of the autonomously driven vehicle 10, for example, at predetermined time intervals. The vehicle speed sensor detects, for example, the number of wheel rotations and uses that number of rotations as a detection signal. The three-axis acceleration sensor is a so-called gyro, and detects the three-dimensional attitude of the autonomously driven vehicle 10 based on the acceleration in the three-axis directions of the vehicle body.

[0027] The surroundings sensor is composed of, for example, three LIDARs mounted near the front and rear bumpers of the vehicle body, and can detect objects on the roadway around the autonomous vehicle 10, i.e., obstacles on the front, rear, left, and right sides, as well as other vehicles. When the surroundings sensor detects an object on the roadway, it sends out a detection signal including the direction and distance of the object.

[0028] As a result, the control unit 17 or the backup control unit 18 grasps the driving conditions of the autonomous vehicle 10, such as its driving position, driving speed, and posture, as well as the position and distance of objects in the forward area, such as obstacles and other driving vehicles, based on detection signals from the position sensor, vehicle speed sensor, three-axis acceleration sensor, and surrounding sensors of the detection unit 19, thereby estimating its own position and determining the progress of the driving signal 15a at that time.

[0029] Here, the specific configurations of the braking unit 13 and the emergency braking unit 20 will be described with reference to FIGS. The braking unit 13 of the autonomous vehicle 10 is disposed in front of the driver's seat 10a of the autonomous vehicle 10 as shown in Figure 4, and includes an operation input unit 21 into which forward and backward movement is input by braking operation under normal conditions, a brake main body unit 22 that brakes each wheel 11a of the running unit 11 of the autonomous vehicle 10 by the forward and backward movement operation of this operation input unit 21, and an operation assisting unit 23 that assists the operation of various devices when braking.

[0030] The autonomous driving control unit 10b installed in the autonomous driving vehicle 10 corresponds to the aforementioned control unit 17, backup control unit 18, operation monitoring unit 16, driving control unit 15 and drive control unit 14, and when the autonomous driving vehicle 10 is being driven, the autonomous driving control unit 10b controls the operation input unit 21 or brake main body unit 22 of the braking unit 13 to brake the wheels (drive wheels) 11a of the driving unit 11.

[0031] 3, the braking unit 13 is made up of fluid pressure equipment 25 such as a hydraulic device, and includes an emergency drive source 26 that holds drive force under normal circumstances and releases the drive force in an emergency, an emergency operation unit 27 that moves the operation input unit 21 forward and backward using the drive force from the emergency drive source 26, and a fluid pressure circuit 31 that connects the emergency drive source 26 and the emergency operation unit 27. Note that the normal state refers to a state in which, when the autonomous driving control unit 10b controls each unit and the autonomous vehicle 10 is traveling, the brake main body unit 22 is activated by a brake operation output from the autonomous driving control unit 10b, and each wheel 11a can be braked, and the emergency state refers to a state in which control by the autonomous driving control unit 10b and input to the brake main body unit 22 are impossible.

[0032] The operation input unit 21 includes a brake pedal 32 located at the feet of the driver's seat 10a to which a brake operation is input, and a brake arm 34 that supports the brake pedal 32, moves forward and backward around a fulcrum 33, and is biased toward the driver. The brake main body 22 transmits or transmits the forward and backward movement input to the operation input unit 21 and brakes each wheel 11a using pressure that is amplified or generated based on the forward and backward movement. The brake main body 22 includes a booster 35 that converts and amplifies the forward and backward movement input of the operation input unit 21 into hydraulic fluid pressure, a master cylinder 36 that distributes the hydraulic fluid pressure, and brake lines that transmit the hydraulic fluid pressure from the master cylinder 36 to each wheel 11a. Attached to the ends of the brake lines are operating units 37, such as disc brakes or drum brakes, for braking each wheel 11a.

[0033] The operation assisting unit 23 is a structure provided in various conventionally known vehicles, and assists the operation of various devices for various purposes, such as ensuring driving stability when the brakes are applied, improving the stability of the vehicle body, and increasing braking force.Although not shown in detail here, for example, an anti-skid mechanism or an ABS mechanism may be installed.

[0034] 3, the emergency drive source 26 made up of the fluid pressure device 25 includes a hollow cylinder 41, a screw shaft 42 made up of a ball screw that penetrates the cylinder 41, a piston 44 that is supported by a ball screw nut 42c that is threaded onto the screw shaft 42 and is arranged in the cylinder 41 so as to be able to advance and retreat by rotation of the screw shaft 42, and that separates a cylinder chamber 43, a biasing unit 45 made up of a compression spring that biases the piston 44 in the axial direction, and an electric unit 46 that rotates, stops, and releases the screw shaft 42. A drive source control unit 28 is provided in the emergency drive source 26, and its operation can be controlled by the drive source control unit 28. The drive source control unit 28 receives information for identifying whether the vehicle is in an emergency or normal state from the automatic driving control unit 10b, and also receives information on the power supply from the battery 10d, information on whether the ignition switch 24 is on, information on the detection of the piston 44 of the cylinder 41, and information on the storage of working fluid in the buffer 61.Based on these information, the operation of the switching valve 66 and motor 71 (described later) is controlled to release drive force from the emergency drive source 26 in a preset emergency.

[0035] The cylinder 41 has a hollow portion 47 that has a circular cross section and extends in the axial direction, and both ends are closed to prevent the working fluid from passing through. The screw shaft 42 is arranged along the axis and is supported at both ends of the cylinder 41 so that it is immovable in the axial direction but rotatable. The screw shaft 42 is arranged to penetrate one end of the cylinder 41 in a liquid-tight manner, with the end side of the screw shaft 42 protruding outside the cylinder 41.

[0036] The piston 44 is threaded onto the screw shaft 42 and housed in the hollow portion 47 of the cylinder 41, and is arranged non-rotatably by being circumferentially locked, for example, by a strip-like guide portion or the like provided in the axial direction within the cylinder 41. The outer periphery of the piston 44 slidably contacts the inner circumferential surface of the hollow portion 47 of the cylinder 41 via a sealant, and the piston 44 is arranged to be able to move forward and backward in the axial direction. Here, detectors 48 consisting of reed switches or limit switches that detect the position of the piston 44 are attached to the top dead center and bottom dead center of the piston 44 of the cylinder 41, respectively. By detecting the position of the piston 44, the suction and discharge of working fluid in the cylinder 41, etc., can be detected.

[0037] The biasing unit 45 is housed in a hollow portion 47 on one end side of the cylinder 41 and is composed of a compression spring arranged around the screw shaft 42. This biasing unit 45 biases the piston 44 in a direction that reduces the volume of the cylinder chamber 43, i.e., toward the other end side. Here, the biasing force of the biasing unit 45 is set so as to obtain a flow rate and fluid pressure of the working fluid that can achieve the intended operation of the other fluid pressure device 25 connected by the fluid pressure circuit 31.

[0038] The emergency operating unit 27 is connected to an emergency drive source 26 consisting of a fluid pressure device 25 via a fluid pressure circuit 31. The emergency operating unit 27 is attached to the vehicle body near the operation input unit 21, specifically to a position on the vehicle rear side of the brake arm 34 that can move the brake arm 34 forward and backward using a pressing member 53. The emergency operating unit 27 is made up of a fluid pressure device 25 that includes a pressing cylinder 51 that moves forward and backward using fluid pressure, and a pressing member 53 that is connected to a rod 51a of the pressing cylinder 51 and is arranged in a non-jointed state so that it can press the operation input unit 21.

[0039] The fluid pressure circuit 31 is connected between a storage unit 60 such as an oil tank that stores hydraulic fluid, the cylinder 41 of the emergency drive source 26, and the pressing cylinder 51 of the emergency actuation unit 27, and supplies and releases the hydraulic fluid to and from the cylinder chamber 43 of the cylinder 41. The fluid pressure circuit 31 is provided with a buffer 61 that is provided in communication with the storage unit 60 and that facilitates the supply and recovery of a sufficient amount of hydraulic fluid to the fluid pressure circuit 31, a supply flow path 62 that is connected to the other end of the cylinder 41 so as to be able to supply hydraulic fluid from the storage unit 60 to the cylinder chamber 43 of the cylinder 41, and a working pressure flow path 63 that releases pressurized fluid from the cylinder chamber 43 and leads it to the emergency actuation unit 27. The supply flow path 62 and the working pressure flow path 63 of the fluid pressure circuit 31 are each provided with a check valve 64.

[0040] The fluid pressure circuit 31 is provided with a return flow path 65 that branches off from the operating pressure flow path 63 and returns the pressurized fluid to the reservoir 60, and a switching valve 66 that serves as a switching unit for selectively allowing flow between the operating pressure flow path 63 and the return flow path 65. The switching valve 66 is configured to switch between being energized in a normal state and being de-energized in an emergency state. Therefore, the switching valve 66 and the check valve 64 allow flow between the reservoir 60 and the cylinder chamber 43 of the cylinder 41 in a normal state, while preventing flow between the cylinder chamber 43 and the pressing cylinder 51 of the emergency actuation unit 27. On the other hand, in an emergency state, flow between the reservoir 60 and the cylinder chamber 43 is prevented, and flow between the cylinder chamber 43 and the pressing cylinder 51 is allowed.

[0041] The electric motor 46 has a motor 71, such as a step motor, that is arranged alongside and fixed integrally to the outside of the cylinder 41. A rotary shaft 72 of the motor 71 is connected to the end of the screw shaft 42 via a transmission unit (not shown). The motor 71 drives the rotary shaft 72 to rotate in one direction when energized, and is rotatable when not energized, and is configured to stop rotation and become non-rotatable when the driving force becomes large when energized, and to maintain that state.

[0042] When the motor 71 is energized, the rotating shaft 72 of the motor 71 rotates, which in turn causes the screw shaft 42 that penetrates the cylinder 41 to rotate, and in a normal energized state, when the rotating shaft 72 of the motor 71 stops, the screw shaft 42 also stops. In an emergency, when the motor is de-energized, the rotating shaft 72 is free to rotate, so when the screw shaft 42 rotates, the rotating shaft 72 of the motor 71 rotates.

[0043] This electric motor 46 is linked to the vehicle's ignition switch 24 and switching of the automatic driving mode, and when the ignition switch 24 is turned ON, the electric motor 46 is energized and driven together with the automatic driving control unit 10b, causing the rotating shaft 72 of the motor 71 to rotate. On the other hand, when the ignition switch 24 is turned OFF, the automatic driving mode of the automatic driving control unit 10b is canceled and power to the electric motor 46 is cut off. In the fluid pressure device 25, the correlation between the biasing force of the biasing unit 45, the moment of inertia of the piston 44, the thread pitch of the screw shaft 42 and the piston 44, and the driving force of the motor 71 of the electric motor 46 is set within a predetermined range in advance, thereby appropriately adjusting the working fluid pressure, discharge speed, etc.

[0044] Next, the operation of the braking unit 13 and emergency braking unit 20 configured as above will be described. First, when the ignition switch 24 is turned ON in the automatic driving mode, the automatic driving control unit 10b and the motor unit 46 are energized, and the rotating shaft 72 of the motor 71 is automatically rotated. As a result, a sufficient amount of working fluid is stored in the buffer 61 from the storage unit 60. In the hollow portion 47 of the cylinder 41, the piston 44 is threadedly engaged with the threaded shaft 42. Therefore, when the rotating shaft 72 of the motor 71 rotates and the threaded shaft 42 rotates, the piston 44 moves in a direction increasing the volume of the cylinder 43. The hydraulic circuit 31 draws the working fluid from the storage unit 60 into the cylinder chamber 43. As the piston 44 moves toward one end of the cylinder 41 against the biasing force of the biasing unit 45, the biasing force of the biasing unit 45 on the piston 44 also increases. As a result, a sufficient amount of working fluid is stored in the cylinder chamber 43 at high fluid pressure.

[0045] When the driving force supplied by the motor 71 becomes large, for example, when the number of rotations reaches a predetermined number or more, the rotational torque reaches a predetermined value or more, or when rotation becomes impossible, the motor 71 stops rotating while remaining energized, and this state is maintained. The autonomous driving control unit 10b performs autonomous driving of the autonomously driven vehicle 10 by transmitting information about the biasing force.

[0046] If, for example, power is not supplied to the automatic driving control unit 10b during automatic driving, power is also not supplied to the electric motor 46. As a result, in the fluid pressure device 25, the motor 71 is de-energized, and the rotary shaft 72 of the motor 71 becomes freely rotatable. Because the piston 44 is biased with a sufficient biasing force, this biasing force causes the piston 44 to move in a direction that reduces the volume of the cylinder chamber 43 while rotating the screw shaft 42. As a result, the working fluid pressurized by the biasing force of the biasing unit 45 is released from the cylinder chamber 43 to the fluid pressure circuit 31.

[0047] In the fluid pressure circuit 31, the switching valve 66 is normally energized, closing the working pressure flow path 63 and opening the return flow path 65. However, when it becomes de-energized in the event of an abnormality, it closes the return flow path 65. Therefore, the pressure of the working fluid released from the cylinder chamber 43 is transmitted to the pressing cylinder 51 of the emergency actuation unit 27 via the working pressure flow path 63. Then, by pressing the operation input unit 21 with the pressing member 53 to input an advance / retreat operation to the brake main body 22, the wheels 11a are braked, and the autonomously driven vehicle 10 is brought to an emergency stop. Furthermore, when an emergency stop signal 15c is input from the autonomous driving control unit 10b to the drive source control unit 28, the drive source control unit 28 controls the operation of the switching valve 66 and the motor 71 to release the driving force from the emergency drive source 26. This similarly brings the autonomously driven vehicle 10 to an emergency stop.

[0048] The braking unit 13 and the emergency braking unit 20 are provided with an emergency driving source 26 that holds driving force under normal circumstances and releases the driving force in an emergency, and an emergency operating unit 27 that causes the operation input unit 21, to which brake operations are normally input, to move forward and backward using the driving force from the emergency driving source 26. Therefore, even in an emergency in which forward and backward movements cannot be input to the operation input unit 21, the driving force that is held under normal circumstances is released from the emergency driving source 26, and the emergency operating unit 27 can use this driving force to move the operation input unit 21 forward and backward, so that the autonomous vehicle 10 can be brought to an emergency stop reliably in an emergency.

[0049] According to the above configuration, in the event of an emergency, the emergency braking unit 20 is controlled by the control unit 17 to drive and control the braking unit 13, and when emergency braking is performed, the emergency operating unit 27 moves the operation input unit 21 of the braking unit 13 forward and backward using the driving force released from the emergency driving source 26, causing the braking unit 13 to perform emergency braking, and the autonomous vehicle 10 can be reliably brought to an emergency stop even if, for example, an abnormality occurs in the power supply.

[0050] The automatically driven vehicle 10 according to the embodiment of the present invention is configured as described above and operates as follows. First, when control unit 17, backup control unit 18, and operation monitoring unit 16 are operating normally, control unit 17 generates driving command 17a based on a detection signal from detection unit 19 and sends it to driving control unit 15 via operation monitoring unit 16. As a result, driving control unit 15 generates driving signal 15a based on driving command 17a and sends it to drive control unit 14. In response to this, drive control unit 14 controls the driving of driving unit 11, steering unit 12, and braking unit 13 in accordance with driving signal 15a, thereby performing autonomous driving of autonomous vehicle 10.

[0051] Here, when control unit 17 detects the occurrence of an emergency situation requiring an emergency stop based on a detection signal from detection unit 19, control unit 17 creates emergency stop command 17b and sends it to driving control unit 15 via operation monitoring unit 16. Driving control unit 15 generates emergency stop signal 15c based on emergency stop command 17b and sends it to emergency braking unit 20. In response to this, emergency braking unit 20 drives braking unit 13 based on emergency stop signal 15c to perform emergency braking, and autonomous vehicle 10 comes to an emergency stop. When detection unit 19 detects an emergency situation, such as a sudden stop of a vehicle ahead, control unit 17 controls emergency braking unit 20 to perform emergency braking using braking unit 13, bringing autonomous vehicle 10 to an emergency stop.

[0052] 5 to 7, a case where an abnormal operation occurs in the control unit 17, the backup control unit 18, and the operation monitoring unit 16. First, a case where an abnormal operation occurs in the control unit 17 will be described with reference to the flowchart in FIG.

[0053] When an abnormal operation occurs in the control unit 17, in step ST1 the backup control unit 18 detects the abnormal operation of the control unit 17. The backup control unit 18 switches to the backup mode in step ST2 and notifies the operation monitoring unit 16 of the backup mode, and also generates a stop command 18c and sends it to the operation monitoring unit 16 in step ST3.

[0054] In response to this, the operation monitoring unit 16 transfers the stop command 18c from the backup control unit 18 to the driving control unit 15 in step ST4. The driving control unit 15 generates a stop signal 15b based on the stop command 18c and sends it to the drive control unit 14. Thus, the drive control unit 14 drives and controls the driving unit 11, the steering unit 12, and the braking unit 13 based on the stop signal 15b, causing the autonomous vehicle 10 to quickly slow down and pull over to the shoulder of the road to stop. If the stop command 18c is for degenerate driving, similar to the degenerate driving by the control unit 17, the drive control unit 14 drives and controls the driving unit 11, the steering unit 12, and the braking unit 13 based on the stop signal 15b for degenerate driving from the driving control unit 15, causing the autonomous vehicle 10 to quickly slow down and pull over to the shoulder of the road to stop.

[0055] In this way, when an abnormality occurs in the operation of control unit 17 or backup control unit 18, driving control unit 15 generates stop signal 15b based on a stop command from backup control unit 18 or control unit 17, and drive control unit 14 drives and controls driving unit 11, steering unit 12, and braking unit 13 based on this stop signal 15b, thereby stopping autonomous vehicle 10 by degenerate driving without immediately bringing it to an emergency stop. Specifically, backup control unit 18 recognizes the shoulder of the road and identifies obstacles and the like on the driving path to the shoulder, just as in the degenerate driving by control unit 17, generates stop signal 15b for degenerate driving, controls drive control unit 14 as described above, and causes autonomous vehicle 10 to slow down and pull over to the shoulder and stop. Therefore, autonomous vehicle 10 can safely and reliably retreat and stop.

[0056] As described above, if an abnormal operation occurs in control unit 17, automatically driven vehicle 10 is evacuated to, for example, a safe location and stopped by backup control unit 18. Therefore, even if an abnormality occurs in the operation of control unit 17, backup control unit 18 that detects the abnormality switches to backup mode and generates a stop command in place of control unit 17, preventing automatically driven vehicle 10 from running out of control and bringing it to a safe and reliable stop.

[0057] If an abnormal operation occurs in backup control unit 18, control unit 17 generates stop command 17c and sends it to operation monitoring unit 16. In response to this, operation monitoring unit 16 transfers stop command 17c from control unit 17 to driving control unit 15. As a result, driving control unit 15 generates stop signal 15b based on stop command 17c and sends it to drive control unit 14. In this way, drive control unit 14 controls the drive of traveling unit 11, steering unit 12, and braking unit 13 based on stop signal 15b, and causes autonomous vehicle 10 to quickly slow down and pull over to the shoulder of the road to stop.

[0058] As described above, if an abnormal operation occurs in the backup control unit 18, the control unit 17 can cause the autonomous vehicle 10 to retreat to a safe location and stop, for example, and the autonomous vehicle 10 will continue to be driven autonomously by the control unit 17 only if the backup control unit 18 is also operating normally.

[0059] Therefore, even if an abnormality occurs in the operation of backup control unit 18, control unit 17 detects the abnormality and generates a stop command, thereby safely and reliably stopping automatically the autonomous vehicle 10 without running out of control. Therefore, only when both control unit 17 and backup control unit 18 are operating normally, control unit 17 continues to operate and drive automatically the autonomous vehicle 10, thereby improving the reliability of the autonomous driving of automatically the autonomous vehicle 10.

[0060] Next, a case where an abnormal operation occurs in both the control unit 17 and the backup control unit 18 will be described with reference to the flowchart of FIG. If abnormal operation occurs in both the control unit 17 and the backup control unit 18, the operation monitoring unit 16 detects the abnormal operation of the control unit 17 and the backup control unit 18 in step ST11, switches to error mode, and generates and sends an emergency stop command 16a to the driving control unit 15 without relying on commands from the control unit 17 and the backup control unit 18. In step ST13, the driving control unit 15 generates an emergency stop signal 15c based on the emergency stop command 16a and sends it to the emergency braking unit 20. As a result, the emergency braking unit 20 immediately drives the braking unit 13 to perform emergency braking and bring the autonomously driven vehicle 10 to an emergency stop. In this way, if abnormal operation occurs in both the control unit 17 and the backup control unit 18, the autonomously driven vehicle 10 immediately makes an emergency stop.

[0061] According to the above configuration, driving control unit 15 generates emergency stop signal 15c in response to emergency stop command 16a and sends it to driving control unit 15, and based on this emergency stop signal 15c, driving control unit 15 controls the operation of emergency braking unit 20 to perform emergency braking using braking unit 13, or emergency braking unit 20 directly receives emergency stop signal 15c and performs emergency braking using braking unit 13. Therefore, automatically driven vehicle 10 reliably makes an emergency stop when abnormal operation occurs in both control unit 17 and backup control unit 18.

[0062] Finally, a case where an abnormal operation occurs in the operation monitoring unit 16 will be described with reference to the flowchart of FIG. If an abnormal operation occurs in operation monitoring unit 16, emergency braking unit 20 detects the abnormal operation of operation monitoring unit 16 in step ST21, and activates braking unit 13 to perform emergency braking in step ST22, and automatically driven vehicle 10 immediately makes an emergency stop in step ST23. In this way, automatically driven vehicle 10 immediately makes an emergency stop when an abnormal operation occurs in operation monitoring unit 16.

[0063] In contrast, if an abnormality occurs in the power supply of autonomously driven vehicle 10, as described above, emergency braking unit 20 detects the abnormality in the power supply and drives braking unit 13 to perform emergency braking, thereby immediately bringing autonomously driven vehicle 10 to an emergency stop. If an abnormality occurs in the power supply of autonomously driven vehicle 10, emergency braking unit 20 drives braking unit 13 to perform emergency braking mechanically, so that autonomously driven vehicle 10 will reliably make an emergency stop even if power is not being supplied.

[0064] According to the above configuration, when an operational abnormality occurs in operation monitoring unit 16 or an abnormality occurs in the power supply, emergency braking unit 20 drives braking unit 13 to bring automatically driven vehicle 10 to an emergency stop by emergency braking. Therefore, when an operational abnormality occurs in operation monitoring unit 16 or an abnormality occurs in the power supply, automatically driven vehicle 10 is reliably brought to an emergency stop.

[0065] The present invention can be embodied in various forms without departing from the spirit thereof. In the embodiment described above, when an abnormal operation of control unit 17 is detected, backup control unit 18 causes autonomous vehicle 10 to quickly slow down and pull over to the shoulder of the road to stop, but this is not limited to this. Depending on the functions provided by backup control unit 18, autonomous vehicle 10 may be stopped on the spot, or, for example, while traveling on a highway or a motorway, autonomous vehicle 10 may be driven to the nearest parking lane or parking area and stopped in an emergency parking lane or a predetermined location within the parking area.

[0066] In the above-described embodiment, if an abnormal operation of control unit 17 is detected, backup control unit 18 performs degenerate driving. However, degenerate driving requires input from surrounding sensors that recognize road shoulders and detect obstacles, etc. while driving up to the road shoulder, and requires advanced calculations, so a computer or the like with relatively high-level functions is used for backup control unit 18. Alternatively, if backup control unit 18 has functions equivalent to those of control unit 17, it may take over the operation of control unit 17 as is, and continue the autonomous driving of autonomous vehicle 10.

[0067] Backup control unit 18 may have only a braking function for stopping the vehicle. In this case, if an operational abnormality occurs in control unit 17, backup control unit 18 controls driving control unit 15 in place of control unit 17 in backup mode, and can control the braking function when driving drive control unit 14. Therefore, backup control unit 18 can have a simpler configuration than control unit 17, and costs can be further reduced. [Explanation of symbols]

[0068] 10 Self-driving vehicles 11 Running part 12 Steering section 13 Braking part 14 Drive control unit 15 Travel control unit 15a Traffic signal 15b Stop signal 15c Emergency stop signal 16 Operation monitoring section 16a Emergency stop command 17 Control Unit 17a Driving command 17b Emergency stop command 17c Stop command 18 Backup control section 18a Driving command 18b Emergency stop command 18c Stop command 19 Detector 19a Various detection signals 20 Emergency braking section 20a Emergency stop signal 21 Operation input section 22 Brake body 23 Motion assistance unit 24 Ignition switch 25 Fluid pressure equipment 26 Emergency drive source 27 Emergency operation unit 28 Drive source control unit 31 Fluid pressure circuit 32 Brake pedal 33 Fulcrum 34 Brake arm 35 Booster 36 Master cylinder 37 Operating unit 41 cylinders 42 screw shaft 43 Cylinder chamber 44 Piston 45 energizing section 46 Electric part 47 Hollow part 48 Detection unit 51 Pressure cylinder 53 Pressing member 60 Storage section 61 buffers 62 Supply channel 63 Operating pressure flow path 64 Check valve 65 Return flow path 66 Switching valve 71 Motor 72 Rotation axis

Claims

1. a driving control unit that drives and controls the driving unit, the steering control unit, and the braking unit; a detection unit that is made up of sensors including a position sensor that detects a driving state, a vehicle speed sensor, a three-axis acceleration sensor, and an ambient sensor; a control unit that generates a driving command based on a detection signal from the detection unit; a driving control unit that generates a driving signal based on the driving command from the control unit and sends it to the drive control unit; and an emergency braking unit that mechanically drives the braking unit to perform emergency braking, In an autonomous vehicle in which, when an emergency occurs, the driving control unit drives and controls the emergency braking unit to perform emergency braking by the braking unit, The system further includes a backup control unit that complements the control unit, and an operation monitoring unit that monitors the operation of the control unit and the backup control unit, The control unit and the backup control unit constantly monitor each other's operations, When the control unit detects an abnormal operation of the backup control unit, the control unit generates a stop command and transmits the stop command to the traveling control unit via the operation monitoring unit; Also, when the backup control unit detects an abnormal operation of the control unit, the backup control unit switches to a backup mode and generates a stop command instead of the control unit, and sends this stop command to the traveling control unit via the operation monitoring unit; When the travel control unit receives the stop command, the travel control unit generates a stop signal and sends it to the drive control unit; An autonomous vehicle, wherein when the drive control unit receives the stop signal, the drive control unit drives and controls the driving unit, steering unit, and braking unit to stop the vehicle.

2. the operation monitoring unit constantly monitors the operation of the control unit and the backup control unit; 2. The autonomous vehicle of claim 1, wherein when the operation monitoring unit detects abnormal operation of both the control unit and the backup control unit, the operation monitoring unit switches to an error mode, and generates an emergency stop command independent of a driving command from the control unit or the backup control unit, and sends the command to the driving control unit or the emergency braking unit.

3. the emergency braking unit constantly monitors the operation of the operation monitoring unit and the power supplied to the control unit, the backup control unit, the operation monitoring unit, the travel control unit, and the drive control unit; 3. The autonomous vehicle according to claim 1, wherein the emergency braking unit drives the braking unit to bring the vehicle to an emergency stop by emergency braking when the emergency braking unit detects an abnormal operation of the operation monitoring unit or an abnormality in the power supply.

4. The autonomous vehicle according to claim 1 , wherein the backup control unit has a function equivalent to that of the control unit.

5. The autonomous vehicle according to claim 1 , wherein the backup control unit has a function of degenerate operation of the control unit.

6. The autonomous vehicle according to claim 1 , wherein the backup control unit only has a braking function for stopping the vehicle.

7. The autonomous driving vehicle according to claim 5 , wherein the drive control unit causes the vehicle to slow down or pull over to a roadside and stop the vehicle based on the stop command from the backup control unit.

8. 8. An autonomous vehicle as claimed in any one of claims 1 to 7, wherein the emergency braking unit is composed of an emergency driving source that releases driving force when an emergency occurs, and an emergency operation unit that moves an operation input unit for braking operation of the braking unit forward and backward using the driving force from the emergency driving source.

Images