Vehicle speed estimation method and vehicle speed estimation device

Abstract

To provide a vehicle speed estimation method and a vehicle speed estimation device capable of improving detection accuracy of a vehicle speed when a vehicle slips.SOLUTION: The vehicle speed estimation method and the vehicle speed estimation device according to the present invention select an appropriate vehicle speed estimation method from a plurality of vehicle speed estimation methods (the first vehicle speed estimation means M1 and the second vehicle speed estimation means M2) based on the state of the front road surface determined via the road surface state determination means 5. Therefore, it is possible to change the method of estimating the vehicle speed VS before detecting the slip of the wheels W1 to W4. As a result, it is possible to suppress a decrease in accuracy of the estimated vehicle speed VS.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle speed estimation method and a vehicle speed estimation device. [Background technology]

[0002] A conventional vehicle speed estimation method is known, for example, from Patent Document 1 below.

[0003] In conventional vehicle speed measurement methods, when the wheels are slipping, the weighting of the output of the wheel rotation speed detection sensor is reduced and the vehicle speed is calculated mainly from the output of the spatial filter speed sensor, making it possible to accurately detect the vehicle speed even when the wheels are slipping. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 07-083943 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional vehicle speed measurement method, the vehicle speed measurement method is changed after wheel slippage is detected, which means that the accuracy of vehicle speed detection is reduced during the period from when wheel slippage occurs until the vehicle speed measurement method is changed, and there is still room for improvement.

[0006] Therefore, the present invention has been devised in consideration of the technical problems of the conventional vehicle speed estimation methods, and aims to provide a vehicle speed estimation method and a vehicle speed estimation device that can improve the accuracy of detecting the vehicle speed when the vehicle is slipping. [Means for solving the problem]

[0007] In one aspect, the present invention comprises a plurality of vehicle speed estimation means for estimating the vehicle speed, which is the traveling speed of the vehicle, and a road surface condition determination means for determining the condition of the road surface ahead of the vehicle, and the vehicle speed estimation means is selected from the plurality of vehicle speed estimation means based on the determination result of the road surface condition determination means. [Effects of the Invention]

[0008] According to the present invention, an appropriate vehicle speed estimation method is selected from among a plurality of vehicle speed estimation methods based on the state of the road surface ahead. This makes it possible to change the vehicle speed estimation method before wheel slip is detected. This makes it possible to suppress a decrease in the accuracy of the estimated vehicle speed. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a system configuration diagram of a vehicle speed estimation device according to the present invention; [Figure 2] 1 is a control flowchart showing a first embodiment of a vehicle speed estimation method according to the present invention. [Figure 3] 3 is a time chart of a vehicle speed estimation method according to the present invention. [Figure 4] 5 is a control flowchart showing a second embodiment of a vehicle speed estimation method according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle speed estimation method and a vehicle speed estimation device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the present embodiment, a vehicle speed estimation method and a vehicle speed estimation device are applied to an automobile.

[0011] (System configuration of vehicle speed estimation device) FIG. 1 shows a system configuration diagram of a vehicle speed estimation device according to the present invention.

[0012] As shown in FIG. 1, the vehicle speed estimation device according to the present invention is mounted on a vehicle V and includes a first camera 1 corresponding to the road surface detection means according to the present invention, a second camera 2 corresponding to the detection means according to the present invention, a wheel speed sensor 3, an acceleration sensor 4, a road surface condition determination means 5, a plurality of vehicle speed estimation means 6, a slip determination means 7, a control device (ECU) 8, a communication device 9 corresponding to the communication means according to the present invention, and a car navigation system (hereinafter abbreviated as "car navigation") 10.

[0013] The first camera 1 is a forward-facing camera attached to, for example, the windshield, and captures an image of the area ahead of the vehicle V to obtain image data of the area ahead of the vehicle V. In other words, the first camera 1 is capable of obtaining images of an area 20 to 30 meters ahead of the vehicle V.

[0014] The second camera 2 is a foot-viewing camera attached to, for example, the lower part of the door mirror M, and acquires image data of the surface of the tire T and the road surface on which the tire T is in contact. In other words, by the second camera 2 acquiring images of the tire T and the road surface on which the tire T is in contact, it becomes possible to estimate the vehicle speed VS, which is the traveling speed of the vehicle V, via vehicle speed estimation means 6, which will be described later.

[0015] The wheel speed sensor 3 is provided on each of the wheels W1 to W4 and detects the number of rotations (rotational speed) of each of the wheels W1 to W4. That is, the wheel speed sensor 3 detects the number of rotations of each of the wheels W1 to W4, and thus the vehicle speed VS can be estimated via vehicle speed estimation means 6, which will be described later.

[0016] The acceleration sensor 4 is, for example, a three-axis modular accelerometer, and detects the acceleration of the vehicle V in the front-rear, left-right, and up-down directions. In other words, by detecting the acceleration of the vehicle V in the front-rear, left-right, and up-down directions, the acceleration sensor 4 makes it possible to detect slippage of the vehicle V via the slip determination means 7, which will be described later.

[0017] The road surface condition determination means 5 determines the condition of the road surface ahead of the vehicle V by using artificial intelligence (AI) based on the image captured by the first camera 1. In particular, in this embodiment, the road surface condition determination means roughly classifies the condition of the road surface ahead into a dry road surface (DRY), an icy road surface (ICE), and a snow-covered road surface (SNOW), and predicts the condition of the road surface ahead based on the determination result.

[0018] The vehicle speed estimation means 6 includes a plurality of vehicle speed estimation means, an example of which is a first vehicle speed estimation means M1 that estimates the vehicle speed VS based on the rotation speed of the wheels W1 to W4 detected by the wheel speed sensor 3, and a second vehicle speed estimation means M2 that estimates the vehicle speed VS based on the moving speed of the tires T and / or the road surface detected based on images acquired by the first camera 1 and / or the second camera 2.

[0019] The slip determination means 7 determines whether the wheels W1 to W4 are slipping by detecting the difference in speed between the tires T and the road surface based on the image captured by the second camera 2. The slip determination means 7 can also determine whether the wheels W1 to W4 are slipping by comparing the detection results of the wheel speed sensor 3 and the acceleration sensor 4, and determining whether the rotation speed of the wheels W1 to W4 detected by the wheel speed sensor 3 is increasing while the acceleration detected by the acceleration sensor 4 is not increasing in accordance with the rotation speed of the wheels W1 to W4. The slip determination means 7 may also determine whether the wheels W1 to W4 are slipping simply when the rotation speed of the wheels W1 to W4 suddenly increases.

[0020] The control device 8 is a well-known ECU mounted on the vehicle V, and determines (selects) one vehicle speed estimation means from multiple vehicle speed estimation means 6 (in this embodiment, a first vehicle speed estimation means M1 and a second vehicle speed estimation means M2) based on the judgment result of the road surface condition judgment means 5 and information acquired by the communication device 9.

[0021] The communication device 9 acquires information on road surface conditions at planned passing points stored in the cloud CS, slippage information of the leading vehicle FR acquired through vehicle-to-vehicle communication, etc. The information on road surface conditions at planned passing points stored in the cloud CS also includes probe information such as slippage information of other vehicles collected and analyzed by the cloud CS via the communication network.

[0022] The car navigation system 10 searches for and outputs a planned route from the destination of the vehicle V. That is, based on the planned route of the vehicle V output by the car navigation system 10, the car navigation system 10 acquires the road surface conditions of the planned passing points stored in the cloud CS via the communication device 9.

[0023] (Explanation of vehicle speed estimation method) FIG. 2 shows a control flowchart illustrating a first embodiment of the vehicle speed estimation method according to the present invention.

[0024] 2, for example, first vehicle speed estimation means M1 is normally selected as vehicle speed estimation means 6, and vehicle speed VS is estimated from the rotational speeds (rotational speeds) of wheels W1 to W4 detected by wheel speed sensor 3 (step S11). Next, based on a forward image of vehicle V captured by first camera 1, it is determined whether the road surface ahead is a slippery surface (snow or ice) (step S12).

[0025] If it is determined that the road surface ahead is a slippery road surface, the vehicle predicts that the road surface ahead is a slippery road surface, and before reaching the road surface, the vehicle speed estimation means 6 switches from the first vehicle speed estimation means M1 to the second vehicle speed estimation means M2 (step S13). After that, the vehicle passes over the slippery road surface, and based on a forward image of the vehicle V captured by the first camera 1, it is determined whether the road surface ahead is not a slippery road surface (snow or ice), in other words, whether the road surface ahead is a dry road surface (dry) (step S14). If the determination is No at this time, the process returns to step S13, and the second vehicle speed estimation means M2 continues, whereas if the determination is Yes, the vehicle speed estimation means 6 switches to the first vehicle speed estimation means M1 (step S15).

[0026] On the other hand, if the determination in step S12 is No, that is, if it is determined that the road surface ahead is not a slippery surface (snow or ice) but a dry road surface (DRY), the vehicle speed estimation means 6 remains as the first vehicle speed estimation means M1 (step S16). After that, while it is predicted that the road surface ahead is not a slippery surface, that is, a non-slip road surface, it is determined whether or not slippage is occurring in the wheels W1 to W4 based on the image captured by the second camera 2 and the detection results of the acceleration sensor 4 (step S17).

[0027] If it is determined that no slippage has occurred in the wheels W1 to W4, the vehicle speed estimation means 6 remains as the first vehicle speed estimation means M1 (step S15). On the other hand, if the determination in step S17 is Yes, that is, if it is determined that slippage has occurred in the wheels W1 to W4, the vehicle speed estimation means 6 is immediately switched from the first vehicle speed estimation means M1 to the second vehicle speed estimation means M2 (step S18).

[0028] After that, after the slip state, it is determined whether the road surface ahead is not a slippery surface (snow or ice), in other words, whether the road surface ahead is dry (DRY) based on the image of the front of the vehicle V captured by the first camera 1 (step S19). If the determination is No at this time, the process returns to step S18, and the second vehicle speed estimation means M2 continues, whereas if the determination is Yes, the vehicle speed estimation means 6 is switched to the first vehicle speed estimation means M1 (step S15).

[0029] FIG. 3 shows a time chart of the vehicle speed estimation method according to the control flow shown in FIG.

[0030] For example, as shown in Figure 3, in the vehicle speed estimation method of this embodiment described above, the first vehicle speed estimation means M1 is normally selected, and then, when it is determined at time t1 based on the forward image of the vehicle V captured by the first camera 1 that the road surface ahead is a slippery surface (snow or ice), the vehicle speed estimation means 6 is immediately switched from the first vehicle speed estimation means M1 to the second vehicle speed estimation means M2.

[0031] Next, while the vehicle V is passing over the slippery road surface, if it is determined at time t2 based on the forward image of the vehicle V taken by the first camera 1 that the road surface ahead is not a slippery road surface (snow or ice), the vehicle speed estimation means 6 switches from the second vehicle speed estimation means M2 to the first vehicle speed estimation means M1 at time t3 after a certain period of time has elapsed.

[0032] Here, if the second vehicle speed estimation means M2 is switched to the first vehicle speed estimation means M1 immediately after it is determined at time t2 that the road surface ahead is not a slippery surface (snow or ice), the vehicle speed VS will be estimated from the rotational speeds of the wheels W1 to W4 detected by the wheel speed sensor 3 while the vehicle V is still traveling on a slippery road surface (snow or ice), and there is a risk that the appropriate vehicle speed VS will not be estimated.

[0033] Therefore, in this embodiment, as described above, the second vehicle speed estimation means M2 is switched to the first vehicle speed estimation means M1 at time t3, which is a predetermined time after it is determined at time t2 that the road surface ahead is not a slippery road surface (snow or ice), i.e., the time until the vehicle V reaches a dry road surface (DRY). That is, if it is predicted from the state of the road surface ahead that the slip of the wheels W1 to W4 will be resolved, the vehicle speed estimation means is switched after the vehicle V reaches the predicted point, and the vehicle speed Vs after the switch is estimated by the first vehicle speed estimation means M1 based on the wheel speeds (the rotation speeds of the wheels W1 to W4 detected by the wheel speed sensor 3). In this way, by providing a predetermined time lag between times t2 and t3, the second vehicle speed estimation means M2 is switched to the first vehicle speed estimation means M1 after the vehicle V reaches a dry road surface (DRY). Therefore, it is possible to estimate an appropriate vehicle speed Vs from the rotation speeds of the wheels W1 to W4 detected by the wheel speed sensor 3.

[0034] Furthermore, regardless of the prediction of the road surface ahead, if it is determined that slippage is occurring in the wheels W1 to W4 while the vehicle V is traveling (time t4), the vehicle speed estimation means 6 is immediately switched from the first vehicle speed estimation means M1 to the second vehicle speed estimation means M2. Thereafter, if it is determined that the road surface ahead is not a slippery surface (snow or ice) based on the image ahead of the vehicle V taken by the first camera 1 (time t5), then, as in the case of t2 to t3, after a certain period of time (t5 to t6) has passed, at the timing (time t6) when it is assumed that the vehicle V has reached a dry road surface (DRY), the vehicle speed estimation means 6 is switched from the second vehicle speed estimation means M2 to the first vehicle speed estimation means M1.

[0035] (Effects of this embodiment) The vehicle speed estimation method and vehicle speed estimation device according to this embodiment select an appropriate vehicle speed estimation method from among a plurality of vehicle speed estimation methods (first vehicle speed estimation means M1 and second vehicle speed estimation means M2) based on the state of the road surface ahead determined by the road surface condition determination means 5. Specifically, if the road surface ahead is predicted to be a dry road surface (DRY) that is less likely to slip, the vehicle speed Vs is estimated from the rotational speeds (rotational speeds) of the wheels W1 to W4 detected by the wheel speed sensor 3. On the other hand, if the road surface ahead is predicted to be a slippery road surface (SNOW or ICE), the vehicle speed Vs is estimated based on the moving speeds of the tires T and the road surface detected from the image acquired by the second camera 2. This makes it possible to change the estimation method for the vehicle speed Vs before detecting slippage of the wheels W1 to W4. This makes it possible to prevent a decrease in the accuracy of the estimated vehicle speed Vs.

[0036] Furthermore, in this embodiment, the vehicle speed VS is estimated based on the image captured by the second camera 2, so that the vehicle speed VS can be appropriately estimated even on a slippery road surface (snow or ice).

[0037] In addition, in this embodiment, by predicting the condition of the road surface ahead based on the forward image of the vehicle V captured by the first camera 1, it becomes possible to determine the condition of the road surface in real time, and appropriate predictions of the road surface condition can be made.

[0038] In addition, in this embodiment, when slippage is predicted on the road surface ahead, the first vehicle speed estimation means M1 is immediately switched to the second vehicle speed estimation means M2 before the vehicle V reaches the road surface where slippage is predicted. As a result, when the vehicle V reaches a road surface that is prone to slippage (snow or ice), the vehicle speed VS can be appropriately estimated via the second vehicle speed estimation means M2 that estimates the vehicle speed VS based on the tire T detected from the image acquired by the second camera 2 and the moving speed of the road surface.

[0039] In this embodiment, when slippage is predicted on the road surface ahead, the vehicle speed estimation means 6 is immediately switched from the first vehicle speed estimation means M1 to the second vehicle speed estimation means M2 before the vehicle reaches the slippage prediction point. This allows an appropriate estimation of the vehicle speed VS from the moment the vehicle reaches a slippery road surface (snow or ice).

[0040] Furthermore, in this embodiment, regardless of the prediction of the road surface ahead, if slippage is detected in the wheels W1 to W4 while the vehicle V is traveling, the vehicle speed estimation means 6 is switched from the first vehicle speed estimation means M1 to the second vehicle speed estimation means M2. As a result, even if slippage in the wheels W1 to W4 cannot be predicted, the vehicle speed estimation means 6 is switched based on the detection of actual slippage, thereby preventing a decrease in the estimation accuracy of the vehicle speed VS.

[0041] Furthermore, in this embodiment, the occurrence of a slip is determined using the acceleration sensor 4, so that the occurrence of a slip can be determined relatively easily without providing any special equipment for determining the occurrence of a slip, such as a camera for slip determination.

[0042] Furthermore, in this embodiment, by using the second camera 2 to determine whether a slip has occurred, it is possible to appropriately determine whether a slip has occurred even on a road surface that has a gradient, such as a slope.

[0043] Second Embodiment 4 shows a second embodiment of the vehicle speed estimation method and vehicle speed estimation device according to the present invention, in which the means for determining the state of the road surface ahead is changed. That is, in the first embodiment, the state of the road surface ahead is determined based on an image ahead of the vehicle V captured by the first camera 1, whereas in the second embodiment, the state of the road surface ahead is determined based on information on the road surface state at the planned passing point that is acquired via the communication device 9 and stored in the cloud CS, slip information on the leading vehicle FR that is acquired via the vehicle-to-vehicle communication, and the like. Note that the basic configuration other than this change is the same as in the first embodiment, and therefore the same components as in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0044] (Explanation of vehicle speed estimation method) FIG. 4 shows a control flowchart illustrating a second embodiment of the vehicle speed estimation method according to the present invention.

[0045] 4, for example, first vehicle speed estimation means M1 is normally selected as vehicle speed estimation means 6, and vehicle speed VS is estimated from the rotational speeds (rotational speeds) of wheels W1 to W4 detected by wheel speed sensor 3 (step S21). Next, based on information on road surface conditions at the planned passing point stored in cloud CS and slip information on the leading vehicle FR acquired through vehicle-to-vehicle communication, it is determined whether the road surface ahead is a slippery surface (snow or ice) (step S22).

[0046] If it is determined that the road surface ahead is a slippery road surface, the vehicle speed estimation means 6 predicts that the road surface ahead is a slippery road surface, and before reaching the road surface, the vehicle speed estimation means 6 switches from the first vehicle speed estimation means M1 to the second vehicle speed estimation means M2 (step S23). After that, after passing the slippery road surface, it is determined whether the road surface ahead is not a slippery road surface (snow or ice), in other words, whether the road surface ahead is a dry road surface (dry), based on information on the road surface condition at the planned passing point stored in the cloud CS and slip information of the leading vehicle FR acquired through vehicle-to-vehicle communication (step S24). If the determination is No at this time, the process returns to step S23, and the second vehicle speed estimation means M2 continues, whereas if the determination is Yes, the vehicle speed estimation means 6 switches to the first vehicle speed estimation means M1 (step S25).

[0047] On the other hand, if the determination in step S22 is No, that is, if it is determined that the road surface ahead is not a slippery surface (snow or ice) but a dry road surface (DRY), the vehicle speed estimation means 6 remains as the first vehicle speed estimation means M1 (step S26). Thereafter, while the road surface ahead is predicted to be not a slippery surface, that is, a non-slip road surface, it is determined whether or not slippage is occurring in the wheels W1 to W4 based on the image captured by the second camera 2 and the detection results of the acceleration sensor 4 (step S27).

[0048] If it is determined that no slippage has occurred in the wheels W1 to W4, the vehicle speed estimation means 6 remains as the first vehicle speed estimation means M1 (step S25). On the other hand, if the determination in step S27 is Yes, that is, if it is determined that slippage has occurred in the wheels W1 to W4, the vehicle speed estimation means 6 is immediately switched from the first vehicle speed estimation means M1 to the second vehicle speed estimation means M2 (step S28).

[0049] After that, after the slip state has passed, it is determined whether the road surface ahead is not a slippery road surface (snow or ice), in other words, whether the road surface ahead is dry (dry) based on information on the road surface condition at the planned passing point stored in the cloud CS and slip information on the leading vehicle FR acquired through vehicle-to-vehicle communication (step S29). If the determination is No at this time, the process returns to step S28, and the second vehicle speed estimation means M2 continues, whereas if the determination is Yes, the vehicle speed estimation means 6 is switched to the first vehicle speed estimation means M1 (step S25).

[0050] (Effects of this embodiment) The vehicle speed estimation method and vehicle speed estimation device of this embodiment predict the condition of the road surface ahead based on road surface information of the planned passing point stored in cloud CS obtained, for example, via communication device 9, and slip information of the leading vehicle FR obtained through vehicle-to-vehicle communication, and can therefore predict the road surface condition even if a road surface detection means such as a camera is not installed or has broken down.

[0051] The present invention is not limited to the configurations exemplified in the above embodiments, and can be freely modified depending on the specifications of the automobile to which the present invention is applied, such as the presence or absence of a first camera 1 and the presence or absence of a communication device 9.

[0052] In particular, the vehicle speed estimation means is not limited to the first vehicle speed estimation means M1 and the second vehicle speed estimation means M2 exemplified in the above embodiment, and any vehicle speed estimation means can be adopted based on vehicle information other than, for example, wheel speed or camera images, depending on the vehicle specifications, etc.

[0053] Furthermore, in each of the above embodiments, the second camera 2 is exemplified as the detection means of the present invention, and the first camera 1 is exemplified as the road surface detection means of the present invention, and the detection means of the present invention and the road surface detection means of the present invention are configured as different entities, but the detection means of the present invention and the road surface detection means of the present invention may be configured as the same entity, for example, both being configured as the first camera 1. [Explanation of symbols]

[0054] 1...First camera (road surface detection means) 2...Second camera (detection means) 3...Wheel speed sensor 4...Acceleration sensor 5...Road surface condition determination means 6...Vehicle speed estimation means 7...Slip determination means 8...Control device 9...Communication device (communication means) 10. Car navigation system M1...first vehicle speed estimation means M2…Second vehicle speed estimation means CS...Cloud FR…Front running vehicle W1~W4…wheels VS…Vehicle speed

Claims

1. a plurality of vehicle speed estimation means for estimating a vehicle speed, which is a traveling speed of the vehicle; a road surface condition determining means for determining the condition of a road surface ahead of the vehicle; Equipped with selecting the vehicle speed estimation means from the plurality of vehicle speed estimation means based on the determination result of the road surface condition determination means; Vehicle speed estimation method.

2. 2. The vehicle speed estimation method according to claim 1, The plurality of vehicle speed estimation means a first vehicle speed estimation means for estimating the vehicle speed based on a wheel speed, which is the rotation speed of a wheel; a second vehicle speed estimation means for estimating the vehicle speed based on information about the vehicle detected by a detection means mounted on the vehicle; A vehicle speed estimation method comprising:

3. 3. The vehicle speed estimation method according to claim 2, The detection means is a camera that captures an image of the surroundings of the vehicle. Vehicle speed estimation method.

4. 3. The vehicle speed estimation method according to claim 2, the condition of the road surface ahead is predicted based on road surface information detected via a road surface detection means for detecting information about the road surface ahead, or information about a vehicle ahead obtained from outside the vehicle via a communication means; Vehicle speed estimation method.

5. 3. The vehicle speed estimation method according to claim 2, When wheel slippage is predicted based on the state of the road surface ahead, the vehicle speed estimation means is switched before the vehicle reaches the predicted point, The vehicle speed when the vehicle reaches the predicted location is estimated by the second vehicle speed estimation means based on the information detected by the detection means. Vehicle speed estimation method.

6. 3. The vehicle speed estimation method according to claim 2, When it is predicted from the state of the road surface ahead that the wheel slip will be eliminated, the vehicle speed estimation means is switched after the vehicle reaches the predicted point, The vehicle speed after the switching is estimated by the first vehicle speed estimation means based on the wheel speed. Vehicle speed estimation method.

7. 3. The vehicle speed estimation method according to claim 2, a control device that determines whether the wheel has slipped, When the control device determines that the wheel is slipping, the vehicle speed estimation is switched to the second vehicle speed estimation means. Vehicle speed estimation method.

8. 8. The vehicle speed estimation method according to claim 7, an acceleration sensor for detecting the acceleration of the vehicle; When the wheel speed is increasing and the acceleration of the acceleration sensor is not increasing, it is determined that the slip is occurring. Vehicle speed estimation method.

9. 8. The vehicle speed estimation method according to claim 7, a camera for capturing an image of the surroundings of the vehicle; The camera captures an image of the tire surface and the road surface, and if the moving speeds of the tire surface and the road surface are different, it is determined that the slippage is occurring. Vehicle speed estimation method.

10. a plurality of vehicle speed estimation means for estimating a vehicle speed, which is a traveling speed of the vehicle; a road surface condition determining means for determining the condition of a road surface ahead of the vehicle; a control device that selects the vehicle speed estimation means from the plurality of vehicle speed estimation means based on a determination result of the road surface condition determination means; A vehicle speed estimation device comprising:

Images