Method of Establishing Friction Model of Power Steering System Using Discrete Points

Abstract

A method for evaluating the frictions in a power steering mechanism, the method including a step of acquiring a series of characterization points, during which are measured, for several different values taken successively by the assistance force during the operation of the steering mechanism, the corresponding friction values, so as to empirically obtain a series of distinct characterization points each associating a measured friction value to a measured value representative of the assistance force, then a step of constructing an empirical friction model, during which a correlation law is established between the characterization points constitutive of the series of characterization points, from the scatter chart formed by the series of the characterization points.

Description

technical field [0001] The invention relates to the general field of methods for managing power steering systems of equipped vehicles, in particular motor vehicles. [0002] More particularly, the invention relates to the consideration of friction in power steering mechanisms. Background technique [0003] In a steering mechanism, the mechanical friction that exists between the components that make up the steering mechanism can affect the relative movement of the components, interfere with power steering system control and cause steering wheel parasitics. [0004] It is therefore useful to detect and quantify these internal frictions for steering mechanisms, eg to compensate for said frictions in order to improve driving comfort and / or to provide the driver with a reliable, intuitive feeling of the steering system reaction forces. [0005] However, it is particularly difficult to determine the friction force precisely, and all the more difficult since said friction force va...

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Problems solved by technology

[0005] However, it is particularly difficult to determine the friction force precisely, and all the more difficult since said friction force varies over time, depending inter alia on the age or degree of wear of the steering components or on the environment in which the vehicle is used (It can be appreciated, for example, that friction tends to increase in cold weather conditions especially due to increased lubricant viscosity)

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