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Road surface state estimation method and road surface state estimation device

A technology for road surface state estimation and road surface state, which is applied in the direction of brakes, etc., can solve the problem of reducing the degree of freedom of the tread pattern

Active Publication Date: 2016-08-03
BRIDGESTONE CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] However, the method using the tire for road surface state estimation poses a problem that the degree of freedom in tread pattern design decreases due to specific restrictions on the tread pattern

Method used

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  • Road surface state estimation method and road surface state estimation device
  • Road surface state estimation method and road surface state estimation device
  • Road surface state estimation method and road surface state estimation device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0063] figure 1 It is a functional block diagram of the road surface state estimation apparatus 10 according to Embodiment 1 of the present invention.

[0064] The road surface state estimation apparatus 10 includes an acceleration sensor 11 as an unsprung front and rear acceleration detection means, a wheel speed sensor 12 as a wheel speed detection means, a wheel speed change amount calculation means 13, a variation range calculation means 14, a storage means 15, and a road surface state estimation means Part 16. Note that each part of the wheel speed change amount calculation part 13 to the road surface state estimation part 16 may be constituted by computer software, for example.

[0065] like figure 1 As shown, the acceleration sensor 11 mounted to the steering knuckle 31 detects the unsprung front and rear acceleration G x . The steering knuckle 31 is a non-rotating side member (vehicle unsprung member) of the wheel unit 30 connected to the hub 33 which rotates tog...

Embodiment 1

[0090] A vehicle was prepared in which the left front wheel was equipped with a studless tire with a tire size of 225 / 55R17 and the steering knuckle of the left front wheel was equipped with an acceleration sensor. Make the vehicle run at a predetermined speed (30km / h~80km / h) on smooth roads (smooth paved roads and icy roads), roads with more bumps (drainage paved roads) and uneven roads, calculated by the research institute The variation range σ(ΔV w ) and the variation range σ(G x )The relationship between. exist figure 2 These results are shown in (a) and (b).

[0091] Note that the range of variation figures are calculated for every 6.5 meters of travel.

[0092] In addition, the wheel speed information of the left wheel is obtained from the vehicle information system (CAN line).

[0093] exist figure 2 In (a) and (b), the horizontal axis represents σ(ΔV w ), and the vertical axis represents σ(G x ). Lighter circles represent data for smooth paved roads, darker ...

Embodiment approach 2

[0098] In Embodiment 1 described above, the state of the road surface during travel is estimated to be one of a smooth road, a road with many irregularities, and an uneven road. However, if image 3 As shown, the road surface state estimating device 10Y equipped with the acceleration sensor 11 for detecting the unsprung front-rear acceleration and the second acceleration sensor 11Y as the unsprung lateral acceleration detecting means on the steering knuckle 31 can be used to estimate the Whether the estimated smooth road is a smooth paved road with a large road surface friction coefficient μ (μ>0.7) or a smooth icy road (ice slope) with a small road surface friction coefficient μ (μ<0.2).

[0099] Note that, as the acceleration sensor 11, a sensor capable of detecting acceleration in two directions, that is, an unsprung front-rear acceleration G, can be used. x and unsprung lateral acceleration G y the acceleration sensor.

[0100] The road surface state estimating device 1...

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Abstract

In order to provide a method that can accurately estimate a road surface state during running using data of unsprung acceleration and wheel speed and an apparatus using the method, an acceleration sensor (11) mounted to a steering knuckle (31) as an unsprung component of a vehicle is utilized to detect the unsprung front-rear acceleration (Gx), and detect the wheel speed (Vw) to calculate the amount of change in the wheel speed (ΔVw). Thereafter, the variation range (σ(ΔVw)) of the change amount of the wheel speed and the variation range (σ(Gx)) of the unsprung front-rear acceleration are calculated. Based on the variation range (σ(ΔVw)) of the amount of change in wheel speed and the variation range (σ(Gx)) of the unsprung front-rear acceleration, it is estimated whether the road surface is rough or smooth.

Description

technical field [0001] The invention relates to a method and a device for estimating the state of a road surface during driving. Background technique [0002] In order to improve the running stability of the vehicle, it is desirable to accurately estimate the state of the road surface or the ground contact state of the tires and to feed the data thus obtained to the vehicle control. If the state of the road surface or the ground contact state of the tires can be estimated in time, advanced controls such as ABS (Antilock Brake System) can be made to work before any hazard avoiding action such as braking, accelerating or steering is taken. Using this facility, the safety of vehicle operation will be significantly improved. [0003] Several methods have been proposed for estimating the state of the road surface. In one of these methods (see, for example, Patent Document 1), the tire for road surface state estimation has deformable structure regions each including a sipe elong...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B60W40/068
CPCB60T8/172B60W40/068B60T2210/12B60W2510/227B60W2520/28B60W40/06B60W2520/105
Inventor 若尾泰通
Owner BRIDGESTONE CORP
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