METHOD FOR CALCULATING THE ADVANCE SPEED OF A RAILWAY VEHICLE
Disclosed is a method for calculating or estimating the speed of a railway vehicle. The method comprises the steps of generating speed signals indicating the angular speed (ω) of the wheels of said at least one controlled axle; estimating, as a function of such angular speed (ω), the value of the adhesion (μ) in the contact area of the wheels of such axle and the rails, using an adhesion observer and computing the value of the speed slip (δ) of the wheels of such controlled axle, generating signals representative of the derivative ( d μ d δ ) of said adhesion (μ) as a function of the slip (δ); generating a driving signal (C(T j+1 )) for torque control devices controlling the torque applied to the wheels applying the driving signal (C(T j+1 )) to said torque control devices and therefore computing the vehicle speed as the linear advance speed of such at least one controlled axle
1 . A method for calculating or estimating the speed of a railway vehicle, at least one axle of which has an associated control system of the adhesion of the wheels to the rails; the method comprising the steps of:
generating speed signals indicating the angular speed (ω) of the wheels of said at least one axle;
estimating, as a function of said angular speed (ω), the value of the adhesion (μ) in the contact area of the wheels of said axle and the rails, using an adhesion observer and calculating the value of the speed slip (δ) of the wheels of said controlled axle,
generating signals representative of the derivative
(
d
μ
d
δ
)
of said adhesion (μ) as a function of the slip (δ) of the wheels of said axle;
generating a driving signal (C(T j+1 )) for torque control means controlling the torque applied to the wheels of said axle, by means of an adaptive control of said derivative signals
(
d
μ
d
δ
)
as a function of an error signal (e((T j+1 )) indicative of the difference between the value of said derivative
(
d
μ
d
δ
)
and a predetermined reference value such as to reduce and keep said difference substantially at zero; and
applying said driving signal (C(T j+1 )) to said torque control means and then computing the vehicle speed as the linear advance speed of said at least one controlled axle.
2 . A method according to claim 1 , wherein said driving signal (C(Tj+1)) is generated by means of an adaptive filtering of LMS type.
3 . A method according to claim 1 , wherein said driving signal (C(Tj+1)) is generated by the time integration of the derivative
(
d
μ
d
δ
)
of the adhesion (μ) as a function of the slip (δ).
4 . A method according to claim 1 , wherein said driving signal (C(Tj+1)) is generated by time integration of the sign of the derivative
(
d
μ
d
δ
)
of the adhesion (μ) as a function of the slip (δ)
5 . A method according to claim 1 , wherein said reference value
(
d
μ
d
δ
)
is equal or greater than zero.
6 . A method for computing or estimating the speed of a railway vehicle of claim 1 in a braking condition.
7 . A method for computing or estimating the speed of a railway vehicle of claim 1 in a traction condition.