Vehicle side slip angle estimation using dynamic blending and considering vehicle attitude information

Claim 3

A method as recited in claim 1 wherein determining a first side slip angle comprises determining a first side slip angle due to gravity, a vehicle attitude change, non-linearity of a side slip angle velocity and the dynamic conditions and an anti-drift integration filter.

Claim 4

A method as recited in claim 1 wherein generating a steady state side slip angle comprises generating a steady state side slip angle in response to a steady state recovery filter.

Claim 5

A method as recited in claim 1 wherein determining a first side slip angle comprises determining a first side slip angle due to gravity, a vehicle attitude change, non-linearity of a side slip angle velocity and the dynamic conditions and an anti-drift integration filter; and wherein generating a steady state side slip angle comprises generating a steady state side slip angle in response to a steady state recovery filter.

Claim 8

A method as recited in claim 5 wherein calculating an attitude change comprises measuring roll rate, and longitudinal acceleration, and determining attitude change based on the roll rate, yaw rate, longitudinal acceleration and lateral acceleration.

Claim 9

A method as recited in claim 5 wherein determining a side slip angle velocity based on the scalar velocity and determining a non-linear side slip angle velocity based on the scalar velocity.

Claim 10

A method as recited in claim 5 wherein determining a second correction comprises determining the second correction as a function of cos 2 (β), cos(2β), cos(β) sin(β), sin(2β), where β is the side slip angle.

Claim 11

A method as recited in claim 5 wherein the step of integrating comprises integrating through an anti-drift integration filtering (ADI filtering) such that an integration cumulative error is eliminated.

Claim 12

A method as recited in claim 5 wherein filtering comprises the steady state recovery filtering.

Claim 13

A method as recited in claim 5 wherein the side slip angle velocity {dot over (β)} has the following formula β . = v . y v x  cos 2  ( β ) - v . x v x  sin  ( β )  cos  ( β ) where {dot over (ν)} y is the time derivative of the lateral velocity, ν x is the time derivative of the longitudinal velocity, ν x is the longitudinal velocity and {dot over (β)} is the time derivative of the side slip angle β.

Claim 14

A method as recited in claim 5 wherein the velocity of the side slip angle obeys the following differential equation β . = [ - ω z + a y - g   sin  ( θ x )  cos  ( θ y ) v x ]  cos 2  ( β ) - v . x v x  sin  ( β )  cos  ( β ) where ν y is the time derivative of the lateral velocity, {dot over (v)} x is the time derivative of the longitudinal velocity, ν x is the longitudinal velocity, and {dot over (β)} is the velocity of the side slip angle, ω z is the yaw rate, θ x is the global roll attitude angle of the vehicle body, θ y is the global pitch attitude angle of the vehicle body.

Claim 15

A method as recited in claim 5 wherein the side slip angle velocity has the following formula   t  DSSA =  [ - ω z + a y - g   sin  ( θ x )  cos  ( θ y ) v x ]  ( 1 + cos  ( DSSA ) ) -  v . x v x  sin  ( DSSA ) where ν y is the time derivative of the lateral velocity, {dot over (v)} x is the time derivative of the longitudinal velocity, ν x is the longitudinal velocity, and {dot over (β)} is the side slip angle velocity, ω z is the yaw rate, θ x is the global roll attitude angle of the vehicle body, θ y is the global pitch attitude angle of the vehicle body, and DSSA is the double side slip angle.

Claim 16

A method as recited in claim 5 wherein generating a steady state side slip angle comprises generating a steady state side slip angle according to the formula: β = l r  ω z v x + - I z  ω z . + M z + t f  M  [ a y - g   sin  ( θ x )  cos  ( θ y ) ] t r  c r where I z is the yaw momentum of inertia, M is the total mass of the vehicle, t f is the distance vehicle center of gravity to the front axle, t r is the distance from the vehicle center of gravity to the rear axle and c r is the cornering stiffness of the rear tire, ω z is a yaw acceleration, ω z is the yaw rate, M z is a yawing moment, g is the gravity constant, a y is the lateral acceleration, θ x is global roll attitude angle of vehicle body, θ y is global pitch attitude of vehicle body, l r is width of rear track, and v x is longitudinal velocity.

Claim 17

A control system for an automotive vehicle comprising: a yaw rate sensor for generating a yaw rate signal; a lateral acceleration sensor generating a lateral acceleration signal; a speed sensor for generating a vehicle scalar velocity signal; a longitudinal acceleration sensor generating a longitudinal acceleration signal; a roll rate sensor generating a roll rate signal; a controller coupled to the yaw rate sensor, the lateral acceleration sensor, the longitudinal acceleration sensor and the roll rate sensor, said controller determining an attitude change in response based on the roll rate signal, the yaw rate signal, longitudinal acceleration signal and lateral acceleration signal, determining a side slip angle velocity based on the scalar velocity, the controller determining a first correction to side slip angle velocity due to gravity and the vehicle attitude change, a second correction to side slip angle velocity due to nonlinearity and a corrected side slip angle based on the first correction and the second correction, said controller integrating the corrected side slip angle velocity to form an integrated side slip angle, generating a steady state side slip angle based on the yaw rate and lateral dynamics of the vehicle; filtering the steady state side slip signal with a steady state recovery filter to obtain a filtered side slip angle, and determining a side slip angle estimation based on the integrated side slip angle and the filtered side slip angle.

Claim 18

A control system for an automotive vehicle comprising: a yaw rate sensor for generating a yaw rate signal; a lateral acceleration sensor generating a lateral acceleration signal; a speed sensor for generating a vehicle scalar velocity signal; a longitudinal acceleration sensor generating a longitudinal acceleration signal; a roll rate sensor generating a roll rate signal; a controller coupled to the yaw rate sensor, the lateral acceleration sensor, the longitudinal acceleration sensor and the roll rate sensor, said controller determining an attitude change in response based on the roll rate signal, the yaw rate signal, longitudinal acceleration signal and lateral acceleration signal, determining a side slip angle velocity based on the scalar velocity, the controller determining a first correction to side slip angle velocity due to gravity and the vehicle attitude change, a second correction to side slip angle velocity due to nonlinearity and a corrected side slip angle based on the first correction and the second correction, said controller integrating the corrected side slip angle velocity to form an integrated side slip angle, generating a steady state side slip angle based on the yaw rate and lateral dynamics of the vehicle; filtering the steady state side slip signal with a steady state recovery filter to obtain a filtered side slip angle, and determining a side slip angle estimation based on the integrated side slip angle and the filtered side slip angle.

Claim 19

A system as recited in claim 15 further comprising a handling and safety system, said controller controlling the safety system in response to the integrated side slip angle.

Claim 20

A control system as recited in claim 16 wherein said handling and safety system comprises an active brake control system.

Claim 21

A control system as recited in claim 16 wherein said handling and safety system comprises an active rear steering system.

Claim 22

A control system as recited in claim 16 wherein said handling and safety system comprises an active front steering system.

Claim 23

A control system as recited in claim 16 wherein said handling and safety system comprises an active anti-roll bar system.

Claim 24

A control system as recited in claim 16 wherein said handling and safety system comprises an active suspension system.

Claim 27

A method as recited in claim 22 further comprising measuring vehicle dynamic conditions, wherein the step of determining a first side slip angle comprises determining a first side slip angle due to the vehicle attitude change and the vehicle dynamic conditions.

Claim 28

A method as recited in claim 23 wherein the step of determining a side slip angle comprises determining a side slip angle due to the vehicle dynamic conditions, the vehicle attitude change, and a non-linearity of a side slip angle velocity.