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Road friction coefficient estimating unit and road friction coefficient estimating method

A technology of road surface friction coefficient and friction coefficient, which is applied to electric steering mechanisms, brakes, etc., can solve the problems of difficult measurement of road surface friction coefficient and difficult application of vehicle models

Active Publication Date: 2013-05-22
JTEKT CORP
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  • Abstract
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AI Technical Summary

Problems solved by technology

Other items used in the calculation formula of the rack shaft force can be measured by various sensors installed on the vehicle, but it is difficult to measure the friction coefficient of the road surface
[0010] Therefore, it is possible to apply the vehicle model only in the linear region that does not contain the road surface friction coefficient, but it is difficult to apply the vehicle model in the saturated region that includes the road surface friction coefficient

Method used

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  • Road friction coefficient estimating unit and road friction coefficient estimating method
  • Road friction coefficient estimating unit and road friction coefficient estimating method
  • Road friction coefficient estimating unit and road friction coefficient estimating method

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Embodiment Construction

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0019] figure 1 It is a schematic diagram showing a schematic configuration of an electric power steering device to which a road surface friction coefficient estimation device according to an embodiment of the present invention is applied. The electric power steering system includes a steering member 2 such as a steering wheel, and a steering shaft 3 connected to the steering member 2 so as to be rotatable together with the steering member 2 . A steering angle sensor 4 that detects a steering angle of the steering member 2 and a torque sensor 10 that detects a steering torque based on rotation of the steering member 2 are provided on the steering shaft 3 . The steering angle sensor 4 is a sensor that detects the rotation angle of the steering shaft 3 by detecting magnetism from, for example, a magnet attached to the circumference of the steering shaft 3 using a Hall se...

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Abstract

A road friction coefficient estimating unit (28) calculates a tire sideslip angle (²) and a cornering force (CF), and estimates a road friction coefficient on the basis of the ratio (”CF / A²) of the calculated cornering force (CF) to the calculated tire sideslip angle (²). A vehicle travels on multiple road surfaces that differ in road friction coefficient (µ), and tire sideslip angles (²) and cornering forces (CF) on the road surfaces are detected in advance. The road friction coefficient estimating unit (28) stores, in a memory (29), a correlation among the detected tire sideslip angles, the detected cornering forces, and the road friction coefficients in the form of numerical values or a mathematical expression, and estimates a road friction coefficient using the correlation stored in the memory (29).

Description

technical field [0001] The present invention relates to a road surface friction coefficient estimation device and method for vehicles. Background technique [0002] Various estimation methods of the road surface friction coefficient are disclosed in JP-A-2006-56388 and the like. [0003] Steering assist electric motors used in electric power steering for vehicles include a motor provided in a steering gear unit composed of a rack and pinion, a motor provided in a steering column mechanism between a steering wheel and a steering gear unit, and the like. In all cases, the movement of the steering shaft coupled to the steering wheels is assisted by an electric motor. [0004] The more the steering wheel is rotated to incline the tires relative to the traveling direction of the vehicle, the more reaction force is received from the road surface, and a larger force is required to rotate the steering wheel. Therefore, in the electric motor described above, the motor current is se...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B60W40/068B60W40/103B62D5/04
CPCB60T8/172B60T2210/12B60T2230/02B60T2210/124
Inventor 河内达磨狩集裕二
Owner JTEKT CORP
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