Patent ID: 8473174

Claim:
A method for determining the vehicle longitudinal velocity in a vehicle, comprising: ascertaining wheel speed using a sensor; determining a wheel longitudinal force as a function of the wheel speed; and ascertaining vehicle longitudinal velocity as a function of the wheel longitudinal force; wherein the wheel longitudinal force (F w,x ) is ascertained as a function of the wheel contact force (F w,z ), a roadway coefficient of friction (μ road ), and a longitudinal slip coefficient of friction (μ w ) which is a function of a wheel longitudinal slip (K): F w,x =max{μ road ,μ w {κ}}· F w,z ; wherein, for equations describing wheel dynamic response {dot over ({circumflex over (x)})}=f{{circumflex over (x)},u}{dot over ({circumflex over (x)})}=f{{circumflex over (x)},u} ŷ=h{{circumflex over (x)}} with {circumflex over (x)}=[{circumflex over (ω)} w {circumflex over (μ)} road ] T u=[M p M b F w,z v x ] T ŷ={circumflex over (ω)} w , an observer equation system of the form {dot over ({circumflex over ( x )})}= f {{circumflex over ( x )},u }− k {{circumflex over ( x )},u }({circumflex over ( y )}− y ), ŷ= h {{circumflex over (x)}} is established, the amplification vector (k{{circumflex over (x)},u}) containing two amplification factors k 1 , k 2 , which are one of constant or dependent on a state variable.