US 11,993,327 B2Granted

Method for estimating and adjusting friction to be adjusted, and controlling hysteresis of a steering wheel torque, and corresponding power steering system

AssigneeJtekt Europe

InventorsNicolas Baudouin, Pierre Larminy

Life of this patent

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Abstract

Method for determining a friction to be adjusted in a power steering system or for modifying a hysteresis of a steering wheel torque applied to a steering wheel of the power steering system, the method including the following steps of: determining a speed, from a measurement of a speed of a part of the power steering system and/or a measurement of the steering wheel torque; determining the friction to be adjusted on the basis of a modified LuGre model, said modified LuGre model determining the friction to be adjusted as a function of a state of the system, a time derivative of the state being determined as a function of said state of the system, the speed, a first gain, and a coulomb friction, according to an equation of the form: z . = v ⁡ ( 1 - α ⁡ ( z , v ) ⁢ σ 0 ⁢ z F c ⁢ sign ⁢ ( v ) ) . [ Math ⁢ 1 ]

Claims10

Dependent claims

A method for determining a friction to be adjusted (F) in a power steering system, the method comprising the following steps:

determining a speed (v), from a measurement of a speed (v) of a part of the power steering system and/or from a measurement of a steering wheel torque (T3) applied to a steering wheel of the power steering system;
determining the friction to be adjusted (F) on the basis of a modified LuGre model (LM),
said modified LuGre model (LM) determining the friction to be adjusted (F) as a function of a state (z) of the system, a time derivative (ż) of the state (z) being determined as a function of said state (z) of the system, the speed (v), a first gain (σ0), a second gain (β), and a coulomb friction (Fc), according to an equation of the form:
z
.
=
v
⁡
(
1
-
α
⁡
(
z
,
v
)
⁢
σ
0
⁢
z
F
c
⁢
sign
⁢
(
v
)
)
⁢
in
⁢
which
:
[
Math
⁢
1
]
α
⁡
(
z
,
v
)
=
{
α
⁢
(
z
)
if
⁢
sign
⁢
(
z
)
=
sign
⁢
(
v
)
0
if
⁢
sign
⁢
(
z
)
≠
sign
⁢
(
v
)
[
Math
⁢
2
]
where sign (z) is the sign of the quantity z and sign (v) is the sign of the quantity v, and in which,
α
⁡
(
z
)
=
{
0
if
⁢
❘
"\[LeftBracketingBar]"
z
❘
"\[RightBracketingBar]"
≤
z
b
⁢
a
1
2
⁢
(
sin
(
π
⁢
❘
"\[LeftBracketingBar]"
z
❘
"\[RightBracketingBar]"
-
z
max
(
1
+
β
)
2
z
max
(
1
-
β
)
)
+
1
)
if
⁢
z
b
⁢
a
≤
❘
"\[LeftBracketingBar]"
z
❘
"\[RightBracketingBar]"
≤
z
max
1
if
⁢
⁢
❘
"\[LeftBracketingBar]"
z
❘
"\[RightBracketingBar]"
≥
z
max
⁢
with
,
[
Math
⁢
3
]
z
max
=
F
c
σ
0
⁢
and
⁢
with
,
[
Math
⁢
4
]
z
b
⁢
a
=
β
·
z
max
.
[
Math
⁢
5
]

206 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/689,063Filed 8 Mar 2022
Priority: FR 21/0297624 Mar 2021
Published: US 2022/0306190 A129 Sep 2022
Granted: 28 May 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

B62D 6/008
Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits: control of…
B62D 5/0481
Characterised by control features of the drive means as such: monitoring the steering system, e.g. failures
B62D 6/10
Responsive only to driver input torque: characterised by means for sensing or determining torque
B62D
Motor vehicles

Family

US 2022/0306190 A1Pre-grant publication · published 29 Sep 2022
US 11,993,327 B2This patent

From the US filing history. Foreign family members aren’t listed.

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