Driving assistance devices, driving assistance methods, and storage media storing programs.

Abstract

The problem to be solved by the present invention is to provide a driving assistance device, driving assistance method, and program that conveys the vehicle's operating status to the user in an easily understandable manner. To solve the above problem, a driving assistance device is provided, wherein the indicator displayed on the display unit includes: understeering state quantity display units U, U1, U2, ..., U7, indicating the understeering state quantity calculated by the calculation unit; an oversteering state quantity display unit, indicating the oversteering state quantity calculated by the calculation unit; and a standard unit N, clamped between the understeering state quantity display units O, O1, O2, ..., O6; and, according to the increase of the understeering state quantity and the oversteering state quantity, an indicator light located away from the standard unit N is illuminated.

Description

Technical Field

[0001] This invention relates to a driving assistance device, a driving assistance method, and a storage medium storing a program. Background Technology

[0002] A vehicle driver message system that provides messages to the driver is currently known (for example, see Patent Document 1). In a vehicle driver message system, for example, a display is provided on the steering wheel, and the display shows, for example, icons indicating that the driver should turn the rudder or drive the vehicle in the correct direction, warning messages about understeer or oversteer, etc.

[0003] [Preliminary Technology Documents]

[0004] (Patent Documents)

[0005] Patent Document 1: Japanese Patent Publication No. 2011-525164 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] In the aforementioned prior art, it is difficult to distinguish between understeering and oversteering, and there is room for improvement in the method of communicating the vehicle's actions to the driver, i.e., the user.

[0008] The purpose of this invention is to provide a driving assistance device, a driving assistance method, and a storage medium storing programs that communicate the vehicle's operating status to the user in an easily understandable manner.

[0009] [Technical means to solve the problem]

[0010] To achieve the above objectives, the present invention provides a driving assistance device (e.g., driving assistance device 1 described later), comprising: a vehicle information acquisition unit (e.g., vehicle information acquisition unit 12 described later) for acquiring information related to the state of the vehicle; a calculation unit (e.g., calculation unit 7 described later) for calculating an index related to the state of steering characteristics based on the acquisition results of the aforementioned vehicle information acquisition unit; and a display unit (e.g., display unit 10 described later) for displaying an indicator based on the index related to the state of steering characteristics, the indicator indicating either understeer or oversteer; the aforementioned indicator having: an understeer state quantity display unit (e.g., understeer state quantity display unit U described later). The calculation unit displays the understeer state (U1, U2, ..., U7), while the oversteer state display unit (e.g., oversteer state display units O, O1, O2, ..., O6, described later) displays the oversteer state calculated by the calculation unit. A standard unit (e.g., standard line N, described later) is sandwiched between the understeer state display unit and the oversteer state display unit, and illuminates indicator lights (e.g., parts U1, U2, ..., U7, O1, O2, ..., O6, described later) located away from the standard unit as the understeer state and oversteer state increases. Thus, it is easy to visually identify whether understeer or oversteer is occurring.

[0011] In this case, it is preferable to provide measuring gauges on both the understeer status display unit and the oversteer status display unit. This allows the vehicle driver, or user, to easily visually identify whether it is an understeer or oversteer state, and the magnitude of the state.

[0012] In this case, it is preferable that the maximum value of the measurement scale of the aforementioned understeering status indicator is set to be greater than the maximum value of the measurement scale of the aforementioned oversteering status indicator. This improves the visibility of the understeering status indicator in the visibility improvement indicator.

[0013] In this case, it is preferable to highlight the oversteering or understeering state when the amount exceeds a predetermined value. Therefore, since normal oversteering is a dangerous state, safety can be improved by making the understeering side appear to have sufficient margin.

[0014] In this case, it is preferable to also include a detection unit for detecting vehicle speed, which changes the aforementioned predetermined value according to the vehicle speed. In a vehicle, if understeering occurs, the higher the vehicle speed, the more outward the turning trajectory bulges outward. If oversteering occurs, the higher the vehicle speed, the more inward the turning trajectory, and the easier it is to slip. In this embodiment, since the predetermined value is used to change, for example, the number of red, blue, green, and orange lights illuminated according to the vehicle speed, a high level of danger can be indicated even if the oversteering or understeering state is very small, as long as the vehicle speed is high.

[0015] In this case, it is preferable to further include a road surface condition acquisition unit that acquires the road surface condition and changes the aforementioned predetermined value according to the road surface condition. If the road surface becomes wet due to rain or snow, or freezes due to a drop in temperature, the coefficient of friction of the road surface decreases, and even under low lateral acceleration caused by low vehicle speed, the track is prone to bulging or slipping. In this embodiment, by changing the number of red, blue, green, and orange lights illuminated according to the road surface condition as a predetermined value, a high danger level can be displayed. In addition to acquiring the road surface condition using the configuration of this embodiment, techniques for estimating the friction between the road surface and the tires using onboard sensors can be used, or changes can be made based on information such as temperature or weather forecasts, or other manual inputs such as windshield wiper information can be used.

[0016] In this case, it is preferable to further include a front-rear acceleration acquisition unit for acquiring front-rear acceleration, and the aforementioned display unit displays the acceleration acquired together with the aforementioned indicator (e.g., point 42 described later). During deceleration, the load on the front of the vehicle increases, and the direction of acceleration shifts towards the oversteer side; during acceleration, the load on the rear of the vehicle increases, and the direction of acceleration shifts towards the understeer side. Therefore, these relationships can be observed simultaneously. As a result, safety can be improved.

[0017] In this case, it is preferable to further include an accelerator pedal opening acquisition unit and a brake pedal opening acquisition unit. The accelerator pedal opening acquisition unit acquires the opening of the accelerator pedal, and the brake pedal opening acquisition unit acquires the opening of the brake pedal. The aforementioned display unit and the aforementioned indicator jointly display the acquired accelerator pedal opening (e.g., accelerator pedal opening AI, described later) and the aforementioned brake pedal opening (e.g., brake pedal opening BI, described later). Thus, during deceleration, the load on the front of the vehicle increases, and the direction of acceleration shifts towards the oversteer side; during acceleration, the load on the rear of the vehicle increases, and the direction of acceleration shifts towards the understeer side. Therefore, these relationships can be observed together. As a result, safety can be improved.

[0018] In this case, it is preferable that the aforementioned calculation unit calculates the friction circle (e.g., friction circle 21 described later) for each wheel based on the acquisition results of the aforementioned vehicle information acquisition unit, and the aforementioned display unit and the aforementioned indicator jointly display the calculated friction circle for each wheel. This allows confirmation of how the load and load coefficient change in understeer and oversteer states.

[0019] In this case, it is preferable that the aforementioned vehicle information acquisition unit also includes a lateral acceleration acquisition unit for acquiring lateral acceleration, and the aforementioned display unit displays the aforementioned lateral acceleration acquired together with the aforementioned indicator (for example, point 42 described later). Thus, if the lateral acceleration is high, there will naturally be a high degree of understeer, and therefore, its balance can be seen.

[0020] In this case, it is preferable that the index related to the aforementioned steering characteristics is at least one of the following: front and rear wheel slip angle difference, stability coefficient, neutral steering point, and static margin value. Therefore, appropriate indexes related to steering characteristics can be selected as needed.

[0021] Furthermore, the present invention provides a driving assistance method, including the step of a computer of the driving assistance device illuminating indicator lights (e.g., U1, U2, ..., U7, O1, O2, ..., O6 described later) at positions far from a standard position based on an increase in the amount of understeer and oversteer. The driving assistance device comprises: a vehicle information acquisition unit (e.g., vehicle information acquisition unit 12 described later) for acquiring information related to the state of the vehicle; a calculation unit (e.g., calculation unit 7 described later) for calculating an index related to the state of steering characteristics based on the acquisition results of the aforementioned vehicle information acquisition unit; and a display unit (e.g., display unit 10 described later) for displaying an index related to the state of steering characteristics based on the aforementioned steering characteristics. The indicator displays an index related to the steering state, indicating either understeer or oversteer; the indicator includes: an understeer state quantity display unit (e.g., understeer state quantity display units U, U1, U2, ..., U7 described later), indicating the understeer state quantity calculated by the calculation unit; an oversteer state quantity display unit (e.g., oversteer state quantity display units O, O1, O2, ..., O6 described later), indicating the oversteer state quantity calculated by the calculation unit; and a standard unit (e.g., a standard line N described later) clamped between the understeer state quantity display unit and the oversteer state quantity display unit.

[0022] Furthermore, the present invention provides a storage medium storing a program for causing a computer of a driving assistance device to execute the following steps, wherein the steps are: illuminating indicator lights (e.g., U1, U2, ..., U7, O1, O2, ..., O6 described later) at positions away from the standard position based on an increase in the amount of understeer and oversteer. The driving assistance device includes: a vehicle information acquisition unit (e.g., vehicle information acquisition unit 12 described later) that acquires information related to the state of the vehicle; a calculation unit (e.g., calculation unit 7 described later) that calculates an index related to the state of steering characteristics based on the acquisition results of the aforementioned vehicle information acquisition unit; and a display unit (e.g., display unit 10 described later) that... The indicator displays an index related to the state of the aforementioned steering characteristics, indicating either understeer or oversteer. The indicator includes: an understeer state quantity display unit (e.g., understeer state quantity display units U, U1, U2, ..., U7 described later) that displays the understeer state quantity calculated by the aforementioned calculation unit; an oversteer state quantity display unit (e.g., oversteer state quantity display units O, O1, O2, ..., O6 described later) that displays the oversteer state quantity calculated by the aforementioned calculation unit; and a standard unit (e.g., standard line N described later) sandwiched between the understeer state quantity display unit and the oversteer state quantity display unit.

[0023] [Invention Effects]

[0024] According to the present invention, a driving assistance device can be provided that communicates the vehicle's operating status to the user in an easily understandable manner. Attached Figure Description

[0025] Figure 1 A block diagram illustrating a driving assistance device as one embodiment of the present invention is shown.

[0026] Figure 2 A diagram illustrating understeering and oversteering indicators displayed on a display unit of a driving assistance device, as an embodiment of the present invention.

[0027] Figure 3 A diagram illustrating the state of understeering as shown in the indicator on the display of a driving assistance device, as an embodiment of the present invention.

[0028] Figure 4 A diagram illustrating the state when the steering overshoot is at its maximum, as shown in the indicator on the display of the driving assistance device, which is an embodiment of the present invention.

[0029] Figure 5 A diagram illustrating the state of insufficient steering in the indicator displayed on the display of a driving assistance device, as an embodiment of the present invention.

[0030] Figure 6 A diagram illustrating a display state where the danger zone of understeering is wider in an indicator on the display unit of a driving assistance device, as an embodiment of the present invention.

[0031] Figure 7 A diagram illustrating the state in which understeering and oversteering areas are equally displayed on an indicator on a display unit of a driving assistance device, as an embodiment of the present invention.

[0032] Figure 8 A diagram illustrating a state in which an oversteering area is displayed more widely in an indicator on a display section of a driving assistance device, as an embodiment of the present invention.

[0033] Figure 9 A diagram illustrating the state of a display on a driver assistance device, where the meter readings are omitted, is shown as an embodiment of the present invention.

[0034] Figure 10 A diagram illustrating, as an embodiment of the present invention, shows the state of the understeering area displayed in monochrome on an indicator on a display unit of a driving assistance device.

[0035] Figure 11 A diagram illustrating the state of the indicators displayed on the display section of the driving assistance device and the friction circles of each tire, as an embodiment of the present invention, is shown.

[0036] Figure 12 A graph showing the longitudinal and lateral accelerations displayed on the display of a driving assistance device, as an embodiment of the present invention, is illustrated using dots.

[0037] Figure 13 A diagram illustrating an indicator of the opening degree of the accelerator pedal and the brake pedal, displayed on a display unit of a driving assistance device, as an embodiment of the present invention.

[0038] Figure 14 A flowchart illustrating the control unit of a driving assistance device according to one embodiment of the present invention is shown. Detailed Implementation

[0039] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 This is a block diagram of driver assistance device 1. Figure 2 A diagram showing understeering and oversteering indicators displayed on the display unit 10 of the driving assistance device 1. Figure 3 A diagram is shown illustrating the state when understeering is at its maximum, as indicated by the indicator on the display unit 10 of the driving assistance device 1. Figure 4 A diagram is shown illustrating the state when the steering overshoot is at its maximum, as indicated by the indicator on the display unit 10 of the driving assistance device 1. Figure 5 A diagram is shown illustrating the state when the steering is below the standard value as indicated on the display unit 10 of the driving assistance device 1.

[0040] Figure 6 A diagram is shown illustrating a wide understeering danger zone in the indicator displayed on the display unit 10 of the driving assistance device 1.

[0041] like Figure 1 As shown, the driving assistance device 1 includes: a control unit 5, a display unit 10, and a vehicle information acquisition unit 12.

[0042] The vehicle information acquisition unit 12 includes: a vehicle acceleration detection unit 121, including a longitudinal acceleration acquisition unit 1211 and a lateral acceleration acquisition unit 1212; a steering angle detection unit 122; a vehicle speed detection unit 123; a road condition acquisition unit 124; an accelerator pedal opening acquisition unit 125; and a brake pedal opening acquisition unit 126.

[0043] The forward and backward acceleration acquisition unit 1211 has a forward and backward acceleration sensor to detect and acquire the forward and backward acceleration of the vehicle. The lateral acceleration acquisition unit 1212 has a lateral acceleration sensor to detect and acquire the lateral acceleration of the vehicle. The steering angle detection unit 122 has a steering angle detection sensor to detect the steering angle. The vehicle speed detection unit 123 has a vehicle speed sensor to detect and acquire the vehicle speed.

[0044] The road surface condition acquisition unit 124 includes a camera for detecting road surface temperature, humidity, etc., and acquires the road surface condition. The accelerator pedal opening acquisition unit 125 includes an accelerator pedal opening sensor for detecting the opening degree of the accelerator pedal and acquires the opening degree of the accelerator pedal. The brake pedal opening acquisition unit 126 includes a brake pedal engagement sensor for detecting the amount of brake pedal depressed and acquires the opening degree of the brake pedal.

[0045] The control unit 5 includes a calculation unit 7, a comparison and arithmetic unit 8, and a friction circle changing unit 9. Specifically, the control unit 5 is composed of a central processing unit (CPU), random access memory (RAM), and read-only memory (ROM), and performs various controls. The CPU is a central processing unit that executes various programs to achieve various functions. RAM serves as the CPU's working area and storage area, while ROM is a storage medium for storing the operating system and programs executed on the CPU. Instead of a CPU, wired logic that cannot be rewritten can be used as a micro-processing unit (MPU) or the control unit 5. Using wired logic as the control unit 5 is effective in improving processing speed. As wired logic, it includes, for example, an application-specific integrated circuit (ASIC). Furthermore, the control unit 5 can be composed of a single semiconductor element or multiple semiconductor elements. In the case where the control unit 5 is composed of multiple semiconductor elements, the various controls described in the claims can be implemented using different semiconductor elements. Furthermore, the control unit 5 can also be configured with passive components such as semiconductor elements and resistors or capacitors.

[0046] The calculation unit 7 calculates, based on the vehicle's steering characteristics, specifically the difference in slip angle between the front and rear wheels during cornering, whether it is an understeer (US) state where the turning radius increases with increasing vehicle speed, an oversteer (OS) state where the turning radius decreases with increasing speed, or a neutral steering state where the turning radius remains unchanged even if the speed changes. Furthermore, based on the detection results from the vehicle acceleration detection unit 121, the calculation unit 7 calculates the friction circle for each wheel, as well as the lateral force generated by the tires (wheels) and the front and rear forces generated by the tires.

[0047] Here, the friction circle corresponds to the limit value of the tire force calculated based on the road surface's coefficient of friction and the force generated by each tire. Specifically, for example, the magnitude of the frictional force between the road surface and the tire is represented by the radius of the friction circle. In this specification, the friction circle is shown as a roughly circular plate shape. The friction circle can be a perfect circle, an ellipse, or a combination of ellipses with different axis lengths.

[0048] The comparison calculation unit 8 compares whether the understeer (US) or oversteer (OS) state exceeds a predetermined state when the steering characteristic is in an understeer (US) state or an oversteer (OS) state. That is, it compares whether the amount of understeer or oversteer exceeds a predetermined value. More specifically, it compares whether the difference in slip angle between the front and rear wheels exceeds a predetermined value. The friction circle changing unit 9 changes the size of the friction circle.

[0049] Based on the calculation results from the calculation unit 7, the display unit 10 displays an indicator of steering characteristics and an image based on the friction circle. The display unit 10 can be composed of a liquid crystal panel or an organic EL panel. Alternatively, the display unit 10 can be installed in a vehicle instrument cluster or DA (Smart Screen Interconnection System), or it can be the screen of an information terminal such as a smartphone or PC (Personal Computer) belonging to the driver or passengers in the vehicle. In this case, the control unit 5 and the information terminal can wirelessly transmit and receive information.

[0050] [Calculation method for steering characteristics]

[0051] The steering characteristics such as understeer and oversteer displayed on the indicator can be represented by values ​​such as front and rear wheel slip angle difference, stability coefficient, neutral steering point, and static margin. In this embodiment, front and rear wheel slip angle difference is used, for example.

[0052] Specifically, when a vehicle is turning, if the slip angle (sideslip) of the front wheels is greater than the slip angle of the rear wheels, it is considered understeer; if the slip angle (sideslip) of the rear wheels is greater than the slip angle of the front wheels, it is considered oversteer. Here, for example, the steering wheel angle is set to δf, the ratio of the steering wheel angle to the front wheel steering angle is set to Ns, the wheelbase is set to l (l), the vehicle's velocity in the direction of travel is set to V, the yaw rate around the vehicle's center of gravity is set to r, and the lateral acceleration at the vehicle's center of gravity is set to a. y The difference in slip angle between the front and rear wheels can be expressed as follows, for example. Furthermore, the intermediate β... f β represents the front wheel slip angle. r This indicates the rear wheel slip angle.

[0053] [Formula 1]

[0054]

[0055] In this embodiment, vehicle speed, yaw rate, and lateral acceleration are acquired by a vehicle information acquisition unit 12 equipped with sensors mounted on the vehicle, but this is not a limitation. For example, external information such as a smartphone or external GPS can also be acquired and calculated. Alternatively, instead of using the above formula to calculate the front and rear wheel slip angle difference, a GPS antenna can be mounted at the front and rear of the vehicle, and the difference in lateral velocity measured therein can be used for calculation.

[0056] Additionally, data such as tire characteristics can be pre-stored to continuously calculate the lateral stiffness of the front and rear wheels (the ratio of the increase in tire lateral force to the increase in tire slip angle), and to calculate the stability coefficient and neutral steering point. The lateral stiffness of the front and rear wheels is set to K. f K rLet the vehicle mass be M, the wheelbase be l (l), and the distance between the vehicle's center of gravity and the front wheels in the fore-and-aft direction be l. f Let l be the distance between the vehicle's center of gravity and the rear wheel in the longitudinal direction. r The stability coefficient can be expressed as follows, for example.

[0057] [Equation 2]

[0058]

[0059] The stability coefficient expressed by the above formula is an example of understeer and oversteer, but the direction of understeer and oversteer can be determined by the "l" in the above formula. f K f -l r K r The symbol "" is used to switch, and the degree can be represented by magnitude. Therefore, if it is composed of "l" f K f -l r K r The expression expressed by "" can be used to replace the above expression.

[0060] [Display of steering characteristics]

[0061] Steering characteristics achieved using driver assistance methods are displayed via an indicator composed of bar graphs. For example... Figure 2 As shown, the indicator displays a gauge representing the intensity of understeer above the standard line N, which represents neutral steering. The gauge is configured such that a bar graph is displayed in seven equal parts above the standard line N, and the illuminated portion (indicator light) in each of the seven divisions above the standard line N increases as the amount of understeer increases, i.e., as the intensity of understeer increases.

[0062] More specifically, among the seven equal parts U1 to U7 above the standard line N of the measuring instrument, the three parts U1 to U3 closest to the top of the standard line N and moving upwards and downwards indicate weak understeering and no problem. The lowest part U1 indicates the weakest understeering, and the understeering increases with the number of parts lit upwards. When these three parts U1 to U3 are lit, they are configured to be illuminated with the same color, such as blue.

[0063] The two sections U4 and U5 indicate a slight understeering condition, but still within the standard level. Both sections being illuminated indicates a stronger understeering condition than when only one is illuminated. When both sections are illuminated, they are configured to be lit in the same color, such as green.

[0064] Furthermore, part U6 refers to the need to take countermeasures such as reducing speed due to increased understeering. When this part is illuminated, the amount of understeering is greater than the predetermined amount under safe conditions (the amount of understeering when part U5 is illuminated), and the understeering is stronger. Therefore, it is configured to be illuminated and highlighted, for example, with an orange light.

[0065] Furthermore, U7, which is the part furthest from the standard line N, indicates an understeering condition that has intensified to a dangerous level, posing a risk of lane departure and necessitating countermeasures such as reducing speed. When this part is illuminated, as mentioned earlier, the amount of understeering is far greater than the predetermined amount under safe conditions (the amount of understeering when part U5 is illuminated), indicating extremely strong understeering. Therefore, it is configured to be illuminated and highlighted, for example, with a red light.

[0066] Additionally, the indicator's measuring scale will be a bar below the standard line N. Figure 3 The display is divided into three equal parts, configured such that, as the oversteering condition increases (i.e., the intensity of the oversteering increases), the illuminated portion (indicator light) of each of the three divisions O1 to O3 located below the standard line N increases. The maximum value of the meter indicating the understeering condition (part U7) is set to be greater than the maximum value of the meter indicating the oversteering condition (part O3).

[0067] More specifically, in the three-part section below the standard line N of the measuring instrument, the uppermost section O1, extending downwards from the lower side of the standard line N, indicates an oversteering state and a tendency for vehicle instability. When this section is illuminated, the oversteering state is greater than the value of the state quantity at the position of the standard line N in the safe state; therefore, it is configured to be illuminated and highlighted, for example, with a yellow light.

[0068] The lower part O2 indicates that due to increased oversteering, countermeasures such as reducing speed are required. When this part is illuminated, the oversteering state value is greater than the value of the state value at the standard line N position under safe conditions. Therefore, it is configured to be illuminated and highlighted with, for example, an orange light.

[0069] Furthermore, the portion O3, which is the part furthest from the standard line N, represents an oversteering state that is prone to slippage or a state where slippage has begun. When this portion is illuminated, the oversteering state value is much greater than the value of the state value of the standard line N position under safe conditions. Therefore, it is configured to be illuminated and highlighted with, for example, a red light.

[0070] like Figure 3 As shown, when understeering is at its strongest state, all parts U1 to U7 of the measuring scale above the standard line N are illuminated. Additionally, as... Figure 4As shown, when oversteering is at its strongest, all parts O1 to O3 of the gauge below the standard line N are illuminated. Additionally, as an example of a state where understeering is slightly formed, ... Figure 5 As shown, part U5 is formed by extending upwards and illuminating the middle position of the measuring target above the standard line N.

[0071] Furthermore, when the display unit 10 is composed of a smartphone screen, users can tap or swipe the indicator on the display unit 10. Additionally, when the display unit 10 is installed on a vehicle instrument cluster or DA (Smart Screen Interconnection System), users can tap or swipe the vehicle touchpad, etc., as described later. Figures 7-13 As shown, the display of the indicator can be switched.

[0072] Figure 7 A diagram is shown illustrating the state in which the understeering area and the oversteering area are equally displayed in the indicator on the display unit 10 of the driving assistance device 1. Figure 8 A diagram is shown illustrating the state in which the oversteering area is displayed more widely in the indicator on the display unit 10 of the driving assistance device 1. Figure 9 A diagram is shown illustrating a state where the meter readings are omitted from the indicator displayed on the display unit 10 of the driving assistance device 1. Figure 10 A diagram is shown illustrating the state of the understeering area displayed in monochrome on the indicator 10 of the driver assistance device 1. Figure 11 A diagram showing the state of the indicators displayed on the display unit 10 of the driving assistance device 1 and the friction circles of each tire is drawn. Figure 12 A graph showing the longitudinal and lateral accelerations displayed on the display unit 10 of the driver assistance device 1 is drawn using dots. Figure 13 A diagram showing an indicator displaying the opening degree of the accelerator pedal and the brake pedal on the display unit 10 of the driving assistance device 1.

[0073] Furthermore, the configuration is such that when the vehicle speed detected by the vehicle speed detection unit 123 is higher than a predetermined value, or when the road surface condition obtained by the road surface condition acquisition unit 124 is a slippery road surface condition (a slippery road surface condition value higher than a predetermined threshold), the control unit 5 controls the display to switch automatically as described later. Figure 6 The indicator shown is displayed.

[0074] Specifically, for example, such as Figure 6As shown, the number of lights illuminated with the same color can be switched to a different number than the previously mentioned display. That is, the display is configured such that blue lights illuminate part U1 to U2 of the measuring scale above the standard line N, green lights illuminate part U3 above it, orange lights illuminate part U4 above it, and red lights illuminate part U5 to U7 above it.

[0075] Additionally, for example, such as Figure 7 As shown, the display of the measurement marks U1 to U5 above the standard line N and the measurement marks O1 to O5 below the standard line N can be switched to show the same quantity. Additionally, for example, as... Figure 8 As shown, the display of the quantities of the measurement scales U1 to U4 above the standard line N can be switched to be less than the quantities of the measurement scales O1 to O6 below. Additionally, for example, as... Figure 9 As shown, the inner side of the indicator is not divided into multiple sections by the measuring scale, but rather the color of the illuminated section changes as it moves away from the standard line N. Additionally, for example, as... Figure 10 As shown, the inside of the indicator is not divided into multiple parts, but can be switched to display with the same color lit up.

[0076] Additionally, by switching displays, for example, Figure 11 As shown, the friction circles for each wheel of the vehicle can be displayed together with the indicator SI, which displays steering characteristics.

[0077] Here, the friction circle corresponds to the limit value of the tire force calculated based on the friction coefficient of the road surface and the force generated by each tire. Specifically, for example, the magnitude of the friction force between the road surface and the tire is represented by the radius of the friction circle. In this embodiment, the friction circle is displayed on the display unit 10 in a generally circular plate shape. The friction circle displayed on the display unit 10 can be a perfect circle, an ellipse, or a combination of ellipses with different axial lengths.

[0078] [Calculation method for the friction circle]

[0079] The following is an example of how to calculate the friction circle. This is just one example; various other calculation methods can also be used.

[0080] First, consider defining the vertical direction as the Z-axis and the vehicle's forward / backward direction as the X-axis. Then, define the axle direction perpendicular to both the X and Z axes as the Y-axis. The calculation of the friction circle for each tire requires the road surface friction coefficient μ and the force Fz generated by each tire. When the vehicle is stationary, the force Fz generated by each tire is determined solely by the vehicle's weight and the vehicle's load balance. That is, the size of the circle represented as the friction circle is determined by the product of the friction coefficient μ and Fz.

[0081] The force Fz generated by each tire is estimated based on the vehicle's characteristics and acceleration. For example, if the wheelbase length is set as L, the tread width as d, the center of gravity height as h, the mass as M, the gravitational acceleration as g, the acceleration in the X-axis direction measured by the vehicle acceleration detection unit 121 as ax, the acceleration in the Y-axis direction as ay, and the front-to-back balance of the left and right load movements as R, the force Fz generated by each tire is calculated by static balance calculation, as shown in equation (3). Here, to simplify the calculation, it is assumed that the center of gravity is located at an equal distance from the front and rear wheels.

[0082] [Formula 3]

[0083]

[0084] Furthermore, unsprung inertial forces are not considered.

[0085] [Display of the friction circle]

[0086] like Figure 11 As shown, the friction circle is displayed as display image 11 in display unit 10. Specifically, display image 11 includes tire friction display image 15A displaying information about the tire of FL (left front wheel), tire friction display image 15B displaying information about the tire of FR (right front wheel), tire friction display image 15C displaying information about the tire of RL (left rear wheel), and tire friction display image 15D displaying information about the tire of RR (right rear wheel).

[0087] Tire friction display images 15A-15D respectively display the 1G display circle 21, which is the friction circle corresponding to the force generated by the tire when the vehicle is stationary, and the maximum friction circle 24, which is the friction circle assuming the tire has extremely high grip. The size of the maximum friction circle 24 can be, for example, 9kN for the front tire and 6kN for the rear tire.

[0088] Furthermore, the coefficient of friction μ can change significantly depending on road conditions, specifically during rain, snow, or icy conditions. Additionally, tire wear can also vary considerably. Therefore, the coefficient of friction μ can be adjusted accordingly when calculating the size of the friction circle 22. Specifically, the friction circle changing unit 9 of the control unit 5 displays a setting screen for changing the size of the friction circle 22 on the display unit 10, allowing the user to change the size of the friction circle 22.

[0089] Furthermore, the driving assistance device can acquire road conditions and tire wear data obtained by the road condition acquisition unit 124, and the friction circle changing unit 9 can change the size of the friction circle 22. Additionally, by measuring and acquiring road surface temperature and humidity, or estimating the coefficient of friction μ based on factors such as the distance traveled after tire replacement, the size of the friction circle 22 can be calculated, changed, and displayed.

[0090] In addition, Figure 11 The vehicle's symbol VI is displayed in the center, but by switching displays, other displays can be used instead of the vehicle's symbol VI. For example, such as... Figure 12 As shown, the display can be switched to show the magnitude and direction of acceleration at the vehicle's center of gravity. The center of gravity display, for example, shows point 42 indicating the direction and magnitude of acceleration at the vehicle's center of gravity, and a trajectory 44 showing its time-varying change. Point 42 is located at... Figure 12 The distance from the center of the circle shown represents the magnitude of the acceleration; point 42 is relative to... Figure 12 The direction of the center of the circle shown indicates the direction of acceleration.

[0091] Furthermore, by switching the display on the display unit 10, it can be displayed together with the steering characteristic indicator. Figure 13 The indicator shown is either an accelerator pedal opening indicator AI or a brake pedal opening indicator BI. In both indicators AI and BI, the display lights indicating the accelerator pedal opening and brake pedal opening are configured such that their dimensions gradually increase from left to right. The current accelerator pedal opening and brake pedal opening are displayed by the currently illuminated indicator light IL. In the accelerator pedal opening indicator AI, as shown... Figure 13 As shown, the engine operating area R1 includes four indicators, starting from the right end, including those indicating the maximum accelerator pedal opening. Therefore, engine operation can be confirmed by observing the accelerator pedal opening as indicated by the illumination of the indicator light IL in the engine operating area R1.

[0092] [Control of Steering Characteristics Display]

[0093] Next, the control of the control unit 5 will be explained. This control is performed by a program executed in the computer of the driving assistance device to control the display of the steering characteristic indicator. Figure 14 A flowchart illustrating the control performed by the control unit 5 of the driving assistance device 1 is shown.

[0094] First, in step S101, the control unit 5 controls the vehicle information acquisition unit 12 to acquire the vehicle's speed V in the direction of travel, yaw rate r around the vehicle's center of gravity, lateral acceleration ay around the vehicle's center of gravity, etc., which are required for calculations such as the front and rear wheel slip angle difference. Then, the control processing performed by the control unit 5 proceeds to step S102.

[0095] First, in step S102, the control unit 5 calculates the front and rear wheel slip angle difference based on the aforementioned equation (1), and calculates the stability coefficient based on the aforementioned equation (2). Then, the control processing performed by the control unit 5 proceeds to step S103.

[0096] First, in step S103, the control unit 5 controls the display unit 10 based on the output value of the front and rear wheel slip angle difference to display an indicator showing the steering characteristics. Then, the control processing performed by the control unit 5 returns to step S101.

[0097] [Effect]

[0098] According to this embodiment, the following effects are achieved.

[0099] In this embodiment, the indicator of the display unit 10 includes: an understeering state indicator displaying the understeering state amount calculated by the calculation unit 7; an oversteering state indicator displaying the oversteering state amount calculated by the calculation unit 7; and a standard line N, which is clamped between the understeering state indicator displaying unit and the oversteering state indicator displaying unit, and an indicator light at a position away from the standard line N is illuminated as the understeering state amount and the oversteering state amount increase. Therefore, it is easy to visually identify whether understeering or oversteering is occurring.

[0100] Furthermore, in this embodiment, measuring gauges are provided on the understeer status display units (parts U, U1, U2, ..., U7) and the oversteer status display units (parts O, O1, O2, ..., U6). This allows the vehicle driver to easily visually identify whether it is an understeer or oversteer state, and the corresponding status value.

[0101] Furthermore, in this embodiment, the maximum value of the metering scale of the understeer status indicator is set to be greater than the maximum value of the metering scale of the oversteer status indicator. This improves the visibility of the understeer status indicator in the visibility improvement indicator.

[0102] Furthermore, in this embodiment, when the oversteering or understeering state exceeds a predetermined value, it is highlighted. Therefore, since normal oversteering is a dangerous state, safety can be improved by making the understeering side appear to have sufficient margin.

[0103] Furthermore, this embodiment includes a speed detection unit that adjusts the number of red, blue, green, and orange lights illuminated according to the vehicle speed as a predetermined value. In a vehicle, if understeering occurs, the higher the speed, the more outward the turning trajectory bulges. If oversteering occurs, the higher the speed, the more inward the turning trajectory, and the easier it is to skid. In this embodiment, since the predetermined value is used to adjust, for example, the number of red, blue, green, and orange lights illuminated, according to the vehicle speed, a high level of danger can be indicated even if the oversteering or understeering state is very small.

[0104] Furthermore, this embodiment also includes a road surface condition acquisition unit that changes the number of illuminated red, blue, green, and orange lights according to the road surface condition as a predetermined value. If the road surface becomes wet due to rain or snow, or freezes due to low temperature, the coefficient of friction of the road surface decreases, and even under low lateral acceleration caused by low vehicle speed, the track is prone to bulging or slipping. In this embodiment, by changing the number of illuminated red, blue, green, and orange lights according to the road surface condition as a predetermined value, a high danger level can be displayed. In addition to acquiring the road surface condition using the configuration of this embodiment, techniques for estimating the friction between the road surface and tires using onboard sensors can be used, or the condition can be changed based on information such as temperature or weather forecasts, or it can be acquired through other manual inputs such as windshield wiper information.

[0105] Furthermore, this embodiment also includes a front-rear acceleration acquisition unit 1211 for acquiring front-rear acceleration, and a display unit 10 for displaying the acceleration acquired together with the indicator. Therefore, during deceleration, the load on the front of the vehicle increases, and the direction of acceleration shifts towards the oversteer side; during acceleration, the load on the rear of the vehicle increases, and the direction of acceleration shifts towards the understeer side. Thus, these relationships can be observed simultaneously. As a result, safety can be improved.

[0106] Furthermore, this embodiment also includes an accelerator pedal opening acquisition unit and a brake pedal opening acquisition unit. The accelerator pedal opening acquisition unit acquires the opening of the accelerator pedal, and the brake pedal opening acquisition unit acquires the opening of the brake pedal. The display unit 10 and the indicator jointly display the acquired accelerator pedal opening and brake pedal opening. Thus, during deceleration, the load on the front of the vehicle increases, and the direction of acceleration shifts towards the oversteer side; during acceleration, the load on the rear of the vehicle increases, and the direction of acceleration shifts towards the understeer side. These relationships can be observed together. As a result, safety can be improved.

[0107] Furthermore, in this embodiment, the calculation unit 7 calculates the friction circle for each wheel based on the acquisition results of the vehicle information acquisition unit 12, and the display unit 10 and the indicator jointly display the calculated friction circle for each wheel. This allows it to be confirmed how the load and load coefficient change in understeer and oversteer states.

[0108] In addition, in this embodiment, the vehicle information acquisition unit 12 also includes a lateral acceleration acquisition unit 1212 for acquiring lateral acceleration, and the display unit 10 displays the aforementioned lateral acceleration acquired together with the indicator on a display such as... Figure 12 Within the circle shown. Therefore, if the lateral acceleration is high, there will naturally be insufficient steering, thus, its equilibrium can be observed.

[0109] Furthermore, in this embodiment, the index related to the steering characteristics is at least one of the following: front and rear wheel slip angle difference, stability coefficient, neutral steering point, and static margin value. Therefore, appropriate indexes related to steering characteristics can be selected as needed.

[0110] This invention is not limited to the above-described embodiments. Modifications and improvements that can achieve the purpose of this invention are included in this invention.

[0111] For example, the configuration of the vehicle information acquisition unit, calculation unit, display unit, understeering status display unit, oversteering status display unit, standard unit, etc. is not limited to the configuration of the vehicle information acquisition unit 12, calculation unit 7, display unit 10, understeering status display unit U, oversteering status display unit O, standard unit N, etc.

[0112] Furthermore, in this embodiment, the steering characteristics displayed using the driving assistance method can be shown using an indicator composed of bar graphs, such as... Figure 2 As shown, a gauge indicating the intensity of understeer is displayed above the standard line N, which represents neutral steering, and a gauge indicating the intensity of oversteer is displayed below the standard line N, but this is not a limitation. For example, a gauge indicating the intensity of understeer could be displayed below the standard line N, and a gauge indicating the intensity of oversteer could be displayed above the standard line N, instead of the above.

[0113] Figure Labels

[0114] 1…Driver assistance devices

[0115] 7…Computing Department

[0116] 10… Display Department

[0117] 12…Vehicle Information Acquisition Department

[0118] 21… Friction Circle

[0119] 42… points

[0120] AI…accelerator pedal opening

[0121] BI… Brake pedal opening

[0122] N…Standard Line (Standards Department)

[0123] O, O1, O2, ..., O6 sections... (Transitional status display section)

[0124] U, U1, U2, ..., U7 sections... (understood steering status indicator, indicator lights)

Claims

1. A driving assistance device, comprising: The vehicle information acquisition department acquires information related to the vehicle's status. The calculation unit, based on the acquisition results of the aforementioned vehicle information acquisition unit, calculates indicators related to the state of steering characteristics and the friction circles for each wheel; and, The display unit displays an indicator based on an index related to the aforementioned steering characteristics, indicating either understeering or oversteering. The aforementioned indicator has: The understeer status display unit displays the understeer status quantity calculated by the aforementioned calculation unit; The oversteering state quantity display unit displays the oversteering state quantity calculated by the aforementioned calculation unit; and, The standard part is clamped between the aforementioned understeering status display part and the aforementioned oversteering status display part; Based on the increase in the aforementioned understeering state amount and the aforementioned oversteering state amount, the indicator light located away from the aforementioned standard part is illuminated. The aforementioned display unit and the aforementioned indicator together display the calculated friction circle for each wheel. The aforementioned friction circles are the friction circles corresponding to the force generated by the tires when the vehicle is stationary, i.e., the 1G display circle, and the friction circles assuming the tires have extremely high grip, i.e., the maximum friction circle.

2. The driving assistance device according to claim 1, wherein, Measuring scales are provided on the aforementioned understeering status display unit and the aforementioned oversteering status display unit.

3. The driving assistance device according to claim 2, wherein, The maximum value of the metering indicator of the aforementioned understeering status indicator is set to be greater than the maximum value of the metering indicator of the aforementioned oversteering status indicator.

4. The driving assistance device according to any one of claims 1 to 3, wherein, When the aforementioned oversteering state value or understeering state value exceeds a predetermined value, it will be highlighted.

5. The driving assistance device according to claim 4, wherein, It also has a vehicle speed detection department. The aforementioned predetermined value is changed according to the vehicle speed.

6. The driving assistance device according to claim 4, wherein, It also has a road condition acquisition unit for acquiring road surface conditions. The aforementioned predetermined values ​​are adjusted according to the road surface conditions.

7. The driving assistance device according to any one of claims 1 to 3, wherein, It also has a forward and backward acceleration acquisition unit to acquire forward and backward acceleration. The aforementioned display unit shows the acceleration obtained together with the aforementioned indicator.

8. The driving assistance device according to any one of claims 1 to 3, wherein, It also includes an accelerator pedal opening acquisition unit for acquiring the opening of the accelerator pedal, and a brake pedal opening acquisition unit for acquiring the opening of the brake pedal. The aforementioned display unit and the aforementioned indicator together display the obtained opening degree of the aforementioned accelerator pedal and the aforementioned brake pedal.

9. The driving assistance device according to any one of claims 1 to 3, wherein, The aforementioned vehicle information acquisition unit also includes a lateral acceleration acquisition unit for acquiring lateral acceleration. The aforementioned display unit shows the aforementioned lateral acceleration obtained together with the aforementioned indicator.

10. The driving assistance device according to any one of claims 1 to 3, wherein, The indicators related to the aforementioned steering characteristics are at least one of the following: front and rear wheel slip angle difference, stability coefficient, neutral steering point, and static margin value.

11. A driving assistance method, comprising the step of a computer of a driving assistance device illuminating an indicator light located away from a standard position based on an increase in an understeer state amount and an oversteer state amount, wherein the driving assistance device comprises: The vehicle information acquisition department acquires information related to the vehicle's status. The calculation unit, based on the acquisition results of the aforementioned vehicle information acquisition unit, calculates indicators related to the state of steering characteristics and the friction circles for each wheel; and, The display unit displays an indicator based on an index related to the aforementioned steering characteristics, indicating either understeering or oversteering. The aforementioned indicator has: The understeering status display unit displays the understeering status quantity calculated by the aforementioned calculation unit; The oversteering state quantity display unit displays the oversteering state quantity calculated by the aforementioned calculation unit; and, The aforementioned standard unit is sandwiched between the aforementioned understeer status display unit and the aforementioned oversteer status display unit. The aforementioned display unit and the aforementioned indicator together display the calculated friction circle for each wheel. The aforementioned friction circles are the friction circles corresponding to the force generated by the tires when the vehicle is stationary, i.e., the 1G display circle, and the friction circles assuming the tires have extremely high grip, i.e., the maximum friction circle.

12. A storage medium storing a program for causing a computer of a driving assistance device to perform the following steps, namely, illuminating an indicator light at a position away from the standard position based on an increase in an understeer state amount and an oversteer state amount, the driving assistance device comprising: The vehicle information acquisition department acquires information related to the vehicle's status. The calculation unit, based on the acquisition results of the aforementioned vehicle information acquisition unit, calculates indicators related to the state of steering characteristics and the friction circles for each wheel; and, The display unit displays an indicator based on an index related to the aforementioned steering characteristics, indicating either understeering or oversteering. The aforementioned indicator has: The understeering status display unit displays the understeering status quantity calculated by the aforementioned calculation unit; The oversteering state quantity display unit displays the oversteering state quantity calculated by the aforementioned calculation unit; and, The aforementioned standard unit is sandwiched between the aforementioned understeer status display unit and the aforementioned oversteer status display unit. The aforementioned display unit and the aforementioned indicator together display the calculated friction circle for each wheel. The aforementioned friction circles are the friction circles corresponding to the force generated by the tires when the vehicle is stationary, i.e., the 1G display circle, and the friction circles assuming the tires have extremely high grip, i.e., the maximum friction circle.

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