Driving control system

Abstract

Depending on the occupant's level of alertness and the shape of the road being traveled, the system eliminates unintended limit settings by the driver to prevent the vehicle from deviating from its lane. [Solution] The system includes a determination unit 110 that determines the driver's level of alertness, a curvature detection unit 120 that detects the curvature of the vehicle's travel path from an image captured in front of the vehicle, a steering torque detection unit 130 that detects the steering torque of the steering wheel by the driver, an assist torque setting unit 140 that calculates the amount of control necessary to return the vehicle to the center of the travel path or the amount of control necessary to avoid deviating from the center of the travel path and sets the assist torque according to the amount of control, a first storage unit 210 that stores map data linking the driver's level of alertness, curvature, and the upper limit of the assist torque, and a control unit 150 that controls the assist torque setting unit 140 to set the assist torque lower than the upper limit if the steering torque exceeds the upper limit of the assist torque based on the detected steering torque and map data.

Description

Technical Field

[0001] The present invention relates to a travel control device.

Background Art

[0002] There is known a travel path departure prevention device that recognizes a travel path based on an image of a travel environment in front of the host vehicle captured by a camera or the like, estimates the position of the host vehicle at a predetermined time after that point for each control cycle, and operates a steering actuator or a brake actuator to assist in avoiding departure when it is predicted that the host vehicle will deviate from the recognized travel path.

[0003] For example, as this type of device, a video camera or an equivalent sensor detects lane marks on a road, and a related signal processor estimates the lateral position of the vehicle with respect to the lane marks. Then, using an electric motor coupled to a steering mechanism, a torque input is applied to the steering mechanism to assist or oppose the steering torque from the driver, and when the steering torque applied by the driver exceeds a predetermined torque threshold, a device that overrides (cancels) that effect is disclosed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technique described in Patent Document 1, the execution of overriding is determined only based on the value of the steering torque input by the driver. Therefore, regardless of the driver's intention or lack of intention, a certain steering torque is input, and when the input steering torque exceeds a predetermined threshold, a limit process is performed to limit the assist torque applied to the steering mechanism. However, with the technology described in Patent Document 1, for example, even if the driver is drowsy and inputting steering torque to the steering wheel, it is a concern that the lane departure prevention control will be weakened, which could result in the vehicle deviating from its lane.

[0006] Therefore, the present invention has been made in view of the above-mentioned problems, and aims to provide a driving control device that prevents the vehicle from deviating from its lane by eliminating unintended limit processing by the driver, depending on the occupant's level of alertness and the shape of the road being driven on. [Means for solving the problem]

[0007] Embodiment 1; One or more embodiments of the present invention propose a driving control device comprising: a determination unit for determining the driver's level of alertness; a curvature detection unit for detecting the curvature of the vehicle's driving path from an image captured in front of the vehicle; a steering torque detection unit for detecting the steering torque of the steering wheel by the driver; an assist torque setting unit for calculating a control amount necessary to return the vehicle to the center of the vehicle's driving path or a control amount necessary to prevent the vehicle from deviating from the center of the vehicle's driving path, and setting an assist torque to be applied to the steering mechanism according to the control amount; a first storage unit for storing map data linking the driver's level of alertness, the curvature, and a first threshold value of the assist torque; and a control unit for controlling the assist torque setting unit to limit the control amount before setting the assist torque if the steering torque exceeds the first threshold value.

[0008] Embodiment 2; One or more embodiments of the present invention propose a driving control device comprising one or more processors and one or more memories communicably connected to the one or more processors, wherein the one or more processors determine the driver's level of alertness, detect the curvature of the vehicle's driving path from an image captured in front of the vehicle, detect the steering torque of the steering wheel by the driver, calculate a control amount necessary to return the vehicle to the center of the vehicle's driving path or a control amount necessary to prevent the vehicle from deviating from the center of the vehicle's driving path, set an assist torque to be applied to the steering mechanism according to the control amount, and control the system to limit the control amount before setting the assist torque if the steering torque exceeds a first threshold, and the one or more memories store map data linking the driver's level of alertness, the curvature, and the first threshold of the assist torque. [Effects of the Invention]

[0009] According to one or more embodiments of the present invention, depending on the occupant's level of alertness and the shape of the road being traveled, it is possible to prevent the vehicle from deviating from its lane by eliminating unintended limiting actions by the driver. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the configuration of a driving control device according to the first embodiment of the present invention. [Figure 2] This figure shows the relationship between assist force torque, assist torque upper limit, and steering torque value according to the first embodiment of the present invention. [Figure 3] This figure shows the processing flow of the driving control device according to the first embodiment of the present invention. [Figure 4] This figure shows the configuration of a driving control device according to a second embodiment of the present invention. [Figure 5] This is map data linking the driver's level of alertness and the upper limit of the assist torque according to the second embodiment of the present invention. [Figure 6]This is a flowchart showing the processing of a driving control device according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0011] <Embodiment> The driving control device according to this embodiment will be described with reference to Figures 1 to 6.

[0012] <First Embodiment> The driving control device 1 according to this embodiment will be described with reference to Figures 1 to 3.

[0013] <Configuration of the travel control device 1> As shown in Figure 1, the driving control device 1 according to this embodiment is configured to include a processor 100 and a memory 200. As shown in Figure 1, the control unit is configured to include a determination unit 110 as a processor 100, a curvature detection unit 120, a steering torque detection unit 130, an assist torque setting unit 140, a processor control unit 150, and a memory 200.

[0014] The determination unit 110 determines the driver's level of alertness. The determination unit 110 determines the driver's level of alertness, for example, based on the driver's image captured by the imaging device. The captured images include moving images and still images. The determination unit 110 detects, for example, the driver's driving posture, eye opening, blinking frequency, etc., obtained from the driver's captured images from the imaging device, and determines the driver's level of alertness. Furthermore, the driver's vital data may be acquired to detect physical or mental fatigue, and the driver's level of alertness may be determined comprehensively in conjunction with the captured images. The determination result from the determination unit 110 is output to the processor control unit 150, which will be described later, via the bus line BL.

[0015] The curvature detection unit 120 detects the curvature of the vehicle's travel path from the captured image in front of the vehicle. Note that, based on an image, a known method can be used to detect the curvature of the vehicle travel path in front of the vehicle. The detection result of the curvature detection unit 120 is output to a processor control unit 150 described later via a bus line BL.

[0016] The steering torque detection unit 130 detects the steering torque of the steering wheel by the driver. The steering torque detection unit 130 is, for example, a steering torque sensor, and outputs a signal corresponding to the steering torque of the steering wheel operated by the driver. The detection result of the steering torque detection unit 130 is output to a processor control unit 150 described later via a bus line BL.

[0017] The assist torque setting unit 140 calculates a control amount necessary to return the vehicle to the center of the vehicle travel path or a control amount necessary to avoid deviation of the vehicle from the center of the vehicle travel path, and sets an assist torque to be applied to the steering mechanism according to the control amount. Here, as an example of the control necessary to return the vehicle to the center of the vehicle travel path or the control necessary to avoid deviation of the vehicle from the center of the vehicle travel path, for example, LKA control or LDP control can be exemplified. The set value of the assist torque by the assist torque setting unit 140 is controlled by a processor control unit 150 described later.

[0018] The processor control unit 150 controls the processing of the entire travel control device 1 based on a control program stored in a ROM (Random Access Memory) or the like not shown. The processor control unit 150, for example, at least based on the steering torque detected by the steering torque detection unit 130 and the map data stored in the first storage unit in the memory 200 described later, when the steering torque exceeds the first threshold value (the upper limit value of the assist torque) of the assist torque, executes control on the assist torque setting unit 140 to set the control amount of the assist torque low. Here, the first threshold can be varied, for example, by tuning. In the driving control device 1 according to this embodiment, the relationship between the assist torque, the upper limit of the assist torque, and the steering torque value is as shown in Figure 2. In other words, as the steering torque value increases, the assist torque also increases, and when the steering torque value exceeds the first threshold (the upper limit of the assist torque), the assist torque begins to decrease and then maintains a constant value. Then, as the steering torque value begins to decrease, the assist torque starts to increase, and when the steering torque value falls below the first threshold (the upper limit of the assist torque), the assist torque also decreases in accordance with the decrease in the steering torque value.

[0019] As shown in Figure 1, the memory 200 is configured to include a first storage unit 210. The first memory unit 210 stores map data that links the driver's level of alertness, the curvature of the vehicle's travel path, and a first threshold (upper limit of assist torque). Here, the first threshold of assist torque (the upper limit of assist torque) increases as the driver's level of alertness decreases, and also increases as the curves of the vehicle's road become sharper.

[0020] <Processing by the travel control device 1> The processing of the driving control device 1 according to this embodiment will be explained using Figure 3.

[0021] First, the processor control unit 150 determines whether or not the steering assistance function is operating in its own vehicle (step S110). If the processor control unit 150 determines that the steering assist function is not operating in its own vehicle (NO in step S110), it switches to a standby state.

[0022] On the other hand, if the processor control unit 150 determines that the steering assistance function is operating in its own vehicle (YES in step S110), it detects the driver's level of alertness based on the determination process performed by the determination unit 110 (step S120).

[0023] Next, the processor control unit 150 activates the curvature detection unit 120 and performs the process of detecting the curvature of the vehicle's travel path from the captured image in front of the vehicle (step S130).

[0024] Then, the processor control unit 150 activates the steering torque detection unit 130 to perform a process to detect the steering torque of the steering wheel by the driver, and performs a map matching process based on the processing result of the driver state detection process in step S120, the processing result of the curvature detection process in step S130, the steering torque value detected by the steering torque detection unit 130, and the map data stored in the first storage unit 210 (step S140).

[0025] As a result of the map matching process, the processor control unit 150 determines whether the steering torque value is equal to or greater than a predetermined first threshold (upper limit of assist torque) (step S150).

[0026] Then, if the processor control unit 150 determines that the steering torque value is equal to or greater than a predetermined first threshold (YES in step S150), it controls the assist torque setting unit 140 to set the assist torque control amount lower (step S160), and then terminates the process.

[0027] On the other hand, if the processor control unit 150 determines that the steering torque value is not equal to or greater than a predetermined first threshold ("NO" in step S150), it terminates the process without performing any control on the assist torque setting unit 140 (step S170).

[0028] <Effects and Actions> As described above, the driving control device 1 according to this embodiment includes a determination unit 110 for determining the driver's level of alertness, a curvature detection unit 120 for detecting the curvature of the vehicle's driving path from an image captured in front of the vehicle, a steering torque detection unit 130 for detecting the steering torque of the steering wheel by the driver, an assist torque setting unit 140 for calculating the amount of control required to return the vehicle to the center of the vehicle's driving path or the amount of control required to prevent the vehicle from deviating from the center of the vehicle's driving path, and for setting the assist torque to be applied to the steering mechanism according to the amount of control, a first storage unit 210 for storing map data linking the driver's level of alertness, curvature, and a first threshold value of the assist torque, and a control unit 150 (processor control unit) for controlling the assist torque setting unit 140 to limit the amount of control before setting the assist torque if the steering torque exceeds the first threshold value. In other words, the control unit (processor control unit) 150 controls the assist torque setting unit 140 to set the assist torque value lower than the first threshold (upper limit of assist torque) when the steering torque exceeds the first threshold (upper limit of assist torque), based on the steering torque detected by the steering torque detection unit 130 and the map data stored in the first memory unit 210 which links the driver's alertness level, curvature, and first threshold (upper limit of assist torque). As described above, by variably controlling the assist torque value using the driver's level of alertness and the curvature of the vehicle's path as parameters, lane keeping control can be continued as much as possible without prioritizing override when the driver's level of alertness is low.

[0029] Furthermore, in the map data of the driving control device 1 according to this embodiment, the first threshold (upper limit of assist torque) increases as the driver's level of alertness decreases and the curvature decreases. In other words, by increasing the first threshold (upper limit of assist torque) as the driver's level of alertness decreases and the curvature decreases, it is possible to reduce the likelihood of the steering torque exceeding the first threshold (upper limit of assist torque) triggering a limiting process that limits the steering torque input to the steering mechanism. Therefore, according to the above configuration, it is possible to prevent unintended limit processing by the driver while also preventing the vehicle from deviating from its lane, depending on the occupant's level of alertness and the shape of the road being traveled.

[0030] <Second Embodiment> The driving control device 1A according to this embodiment will be described with reference to Figures 4 to 6.

[0031] <Configuration of the travel control device 1A> As shown in Figure 4, the control unit of the driving control device 1A according to this embodiment is configured to include a determination unit 110 as a processor 100A, a curvature detection unit 120, a steering torque detection unit 130, an assist torque setting unit 140, a processor control unit 150A, and a memory 200. Note that components bearing the same reference numerals as those in the first embodiment have similar functions, and therefore, a detailed explanation thereof will be omitted.

[0032] The processor control unit 150A controls the overall processing of the driving control device 1A based on a control program stored in a ROM (Random Access Memory) or the like (not shown). The processor control unit 150A, for example, based on map data stored in the second memory unit (described later), will release the assist torque setting of the assist torque setting unit 140 if the steering torque exceeds a second threshold for releasing the assist torque setting of the assist torque setting unit 140.

[0033] As shown in Figure 4, the memory 200 is configured to include a first storage unit 210 and a second storage unit 220.

[0034] The second memory unit 220 stores map data that links the driver's level of alertness with a second threshold value that cancels the assist torque setting of the assist torque setting unit 140. Figure 5 shows an example of map data. As shown in Figure 5, the map data is, for example, map data that links the driver's level of alertness with a second threshold for disabling the assist torque setting. The driver's level of alertness is classified into categories such as "normal state," "drowsy state," "falling asleep," and "distracted state," and a second threshold is associated with each of these classifications to release the assist torque setting corresponding to that classification. As shown in Figure 5, the second threshold for disabling the assist torque setting increases as the driver's level of alertness transitions from "normal state" to "drowsy state," and from "drowsy state" to "falling asleep" or "distracted state." Specifically, as shown in Figure 5, for example, if the normal state is "X (Nm)", the second threshold when transitioning from the "normal state" to the "drowsy state" is "X + α (Nm)", and the second threshold when transitioning from the "drowsy state" to the "dozing state" or "distracted state" is "X + β (Nm)". Here, since α < β, the second threshold for releasing the assist torque setting becomes larger as the driver transitions from a "normal state" to a "drowsy state," and from a "drowsy state" to a "slumbering state" or "distracted state."

[0035] <Processing by the travel control device 1A> The processing of the travel control device 1A according to this embodiment will be explained using Figure 6.

[0036] First, the processor control unit 150A determines whether or not the steering assist function is operating in its own vehicle (step S110). If the processor control unit 150A determines that the steering assist function is not operating in its own vehicle (NO in step S110), it switches to a standby state.

[0037] On the other hand, if the processor control unit 150A determines that the steering assistance function is operating in its own vehicle ("YES" in step S110), it detects the driver's state based on the driver's alertness level determination process performed by the determination unit 110 (step S120).

[0038] Next, the processor control unit 150A activates the curvature detection unit 120 and executes the process of detecting the curvature of the vehicle's travel path from the captured image in front of the vehicle (step S130).

[0039] Then, the processor control unit 150A activates the steering torque detection unit 130 to perform a process to detect the steering torque of the steering wheel by the driver, and performs a map matching process based on the processing result of the driver state detection process in step S120, the processing result of the curvature detection process in step S130, the steering torque value detected by the steering torque detection unit 130, and the map data stored in the first storage unit 210 (step S140).

[0040] As a result of the map matching process, the processor control unit 150A determines whether the steering torque value is equal to or greater than a predetermined first threshold (upper limit of assist torque) (step S150).

[0041] Then, if the processor control unit 150A determines that the steering torque value is not equal to or greater than a predetermined first threshold ("NO" in step S150), it terminates the process without performing any control on the assist torque setting unit 140 (step S170).

[0042] On the other hand, if the processor control unit 150A determines that the steering torque value is equal to or greater than a predetermined first threshold (YES in step S150), it controls the assist torque setting unit 140 to set the assist torque value lower than the upper limit of the assist torque (step S160).

[0043] Next, the processor control unit 150A determines whether the steering torque value is equal to or greater than a predetermined second threshold (the upper limit for releasing the assist torque setting) (step S210).

[0044] The processor control unit 150A terminates the process if it determines that the steering torque value is not equal to a predetermined second threshold (the upper limit for releasing the assist torque setting) ("NO" in step S210).

[0045] On the other hand, if the processor control unit 150A determines that the steering torque value is equal to or greater than a predetermined second threshold (the upper limit for disabling the assist torque setting) ("YES" in step S210), it turns off the limit processing and terminates all processing related to the steering assistance function.

[0046] <Effects and Actions> As described above, the driving control device 1A according to this embodiment includes a second storage unit 220 that stores map data linking the driver's level of alertness with an upper limit value (second threshold) for releasing the assist torque setting of the assist torque setting unit 140. The processor control unit 150A releases the assist torque setting of the assist torque setting unit 140 based on the map data stored in the second storage unit 220 if the steering torque exceeds the upper limit value (second threshold) for releasing the assist torque setting of the assist torque setting unit 140. In other words, the processor control unit 150A, based on the map data stored in the second memory unit 220, will release the assist torque setting of the assist torque setting unit 140 if the steering torque exceeds the upper limit value (second threshold) for releasing the assist torque setting of the assist torque setting unit 140. As described above, by variably controlling the assist torque value using the driver's level of alertness and the curvature of the vehicle's path as parameters, lane keeping control can be continued as much as possible without prioritizing override when the driver's level of alertness is low. Therefore, with the above configuration, when the driver's level of alertness is low, it is possible to prevent the vehicle from deviating from the lane (the center of the road) unintentionally. In addition to the above, the assist torque value is variably controlled using the driver's level of alertness and the curvature of the vehicle's travel path as parameters. Furthermore, based on the map data stored in the second memory unit 220, if the steering torque exceeds the upper limit value (second threshold) for releasing the assist torque setting of the assist torque setting unit 140, the assist torque setting of the assist torque setting unit 140 is released, thereby allowing the steering assistance function to continue when the driver is in an abnormal state.

[0047] Furthermore, the driving control devices 1 and 1A of the present invention can be realized by recording the processing of the processor control units 150 and 150A onto a recording medium readable by a computer system, and then having the processor control units 150 and 150A read and execute the program recorded on this recording medium. The computer system referred to here includes hardware such as an operating system and peripheral devices.

[0048] Furthermore, "computer system" includes the homepage provisioning environment (or display environment) if the WWW (World Wide Web) system is being used. The above program may also be transmitted from the computer system in which the program is stored to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, "transmission medium" for transmitting the program refers to a medium that has the function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.

[0049] Furthermore, the above program may be intended to implement some of the functions described above. It may also be a so-called differential file (differential program) that can implement the aforementioned functions in combination with programs already recorded in the computer system.

[0050] While embodiments of this invention have been described in detail above with reference to the drawings, all driving control devices that can be implemented by those skilled in the art by appropriately modifying the design based on the driving control devices 1 and 1A described above as embodiments of the present invention also fall within the technical scope of the present invention, insofar as they encompass the gist of the present invention. Within the scope of the concept of this invention, a person skilled in the art can conceive of various modifications and alterations, and it is understood that these modifications and alterations also fall within the technical scope of this invention. For example, any embodiment described above that a person skilled in the art has modified by adding, deleting, or changing the design of components, or by adding, omitting, or changing the conditions of a process, is also included within the technical scope of the present invention, as long as it retains the essence of the present invention.

[0051] Furthermore, any other effects and advantages brought about by the embodiments described herein that are obvious from this specification or that can be appropriately conceived by those skilled in the art are naturally considered to be brought about by the present invention. Various inventions can be formed by appropriately combining the multiple components disclosed in the above embodiments. For example, some components may be removed from all the components shown in the embodiment. Furthermore, components from different embodiments may be combined as appropriate. [Explanation of Symbols]

[0052] 1; Driving control device 1A; Travel control device 100; processor 100A; Processor 110; Judgment section 120; Curvature detection unit 130; Steering torque detection unit 140; Assist Torque Setting Section 150; Processor control unit 150A; Processor Control Unit 200; memory 200A; Memory 210; First memory unit 220; Second memory unit

Claims

1. A determination unit that determines the driver's level of alertness, A curvature detection unit that detects the curvature of the vehicle's path from an image captured in front of the vehicle, A steering torque detection unit that detects the steering torque of the steering wheel by the driver, An assist torque setting unit calculates the amount of control required to return the vehicle to the center of the vehicle path or the amount of control required to prevent the vehicle from deviating from the center of the vehicle path, and sets the assist torque to be applied to the steering mechanism according to the amount of control; A first storage unit that stores map data linking the driver's level of alertness, the curvature, and a first threshold value of the assist torque, A control unit that controls the assist torque setting unit to limit the control amount when the steering torque exceeds the first threshold, and then set the assist torque, A driving control device characterized by being equipped with

2. The driving control device according to claim 1, characterized in that the map data has a first threshold value for the assist torque that increases as the driver's level of alertness decreases and the curvature decreases.

3. The system includes a second storage unit that stores map data linking the driver's level of alertness with a second threshold value of the assist torque that cancels the assist torque setting of the assist torque setting unit, The driving control device according to claim 1, characterized in that the control unit, based on the map data stored in the second storage unit, cancels the lane keeping control, including the ALK control or LDP control, when the steering torque exceeds a second threshold of the assist torque that cancels the assist torque setting in the assist torque setting unit.

4. One or more processors, and one or more memories that are communicably connected to the one or more processors, Equipped with, The one or more processors described above are The driver's level of alertness is determined, The curvature of the vehicle's path is detected from the image captured in front of the vehicle. The steering torque of the steering wheel by the aforementioned driver is detected, The system calculates the amount of control required to return the vehicle to the center of the vehicle path or the amount of control required to prevent the vehicle from deviating from the center of the vehicle path, and sets the assist torque to be applied to the steering mechanism according to the amount of control. At a minimum, the control is performed to limit the control amount when the steering torque exceeds a first threshold, and then set the assist torque. A driving control device characterized in that one or more of the memories store map data linking the driver's level of alertness, the curvature, and a first threshold value of the assist torque.

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