×

Method and apparatus for measuring or controlling friction

  • US 5,814,718 A
  • Filed: 05/02/1997
  • Issued: 09/29/1998
  • Est. Priority Date: 11/04/1994
  • Status: Expired due to Fees
First Claim
Patent Images

1. Method for measuring or controlling friction relationships when a pneumatic rubber wheel and a surface interact during rolling motion under slip conditions between the wheel and the surface, comprisingcontinuous measurement of the linear velocity v of the wheel axle in relation to the surface and continuous measurement of the rotational velocity of the wheel within an acceleration or deceleration time interval during the rolling motion of the wheel in relation to the surface,calculation of a corresponding, varying slip speed Vs from said linear velocity v being measured and said rotational velocity being measured while taking the wheel radius into account, andcalculation of friction relationships occuring during said time interval,characterized in that measurement values or control parameters relating to said friction relationships are calculated as a function of the varying slip speed Vs and the linear velocity v on the basis of the following relation(s):

  • 
    
    space="preserve" listing-type="equation">μ

    .sub.max =-f+g·

    STDslope-h·

    A.sub.r (v,V.sub.s)where μ

    max is the maximum friction valueSTDslope is standard deviation of the surface texture slope angles, as measured for example with a known measurement method,A (v,Vs) is the real or total contact area between the wheel and the surface, as a function of the velocities v and Vsand ##EQU11## where D=fractal dimensionG=fractal scaling factorL=upper wave length cut-off limit for a chosen number of sinusoidal wavesL=lower wave length cut-off limit for a chosen number of sinusoidal wavesσ

    =stress-factor for the rubber wheelτ

    =the rubber wheel relaxation spectraη

    =the rubber wheel viscosityδ

    =rubber wheel shape-factorb=the length of the contact area between the wheel and the surfacer=the rubber wheel radiusand where f, g and h are constants.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×