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Independent Suspension - K and C

Independent kinematics and compliance test suspension

  • Library:
  • Vehicle Dynamics Blockset / Suspension

  • Independent Suspension - K and C block

Description

In the Vehicle Dynamics Blockset™ library, there are two types of suspension blocks that implement the kinematics and compliance (K and C) test suspension characteristics measured from simulated or actual laboratory suspension tests.

BlockSuspension type SettingImplementation

Twist-Beam Suspension - K and C

Twist-Beam Suspension - K and C

Independent front and twist-beam rear

Kinematics and compliance effects of:

  • Independent suspension on a front axle with two wheels

  • Twist-beam suspension on a rear axle with two wheels

For more information, see Twist-Beam Suspension - K and C.

Independent Suspension - K and C

Independent Suspension - K and C

Independent front and rear

Kinematics and compliance effects of four independent suspensions on a vehicle with two axles and two wheels per axle.

K and C Effects on Suspension

To determine the overall suspension forces and geometric effects on the vehicle and wheels, the block adds the individual effects from kinematic (bounce, roll, steering) and compliance (longitudinal and lateral forces, aligning moments) inputs. Specifically, the block multiplies the suspension geometry states by either gradient or table values to determine the K and C effects on wheel orientation and suspension forces.

Wheel orientation:

  • Camber, caster, and steer angles

  • Lateral wheel center displacement

  • Longitudinal wheel center displacement

Vertical suspension forces:

  • Anti-sway bar

  • Shock force

  • Wheel rate

  • Contact patch swing arm (CPSA) force

  • Longitudinal side view swing arm (SVSA) anti-effects

Camber, Caster, and Steer Angles

The block uses these parameters to account for the K and C effects on the camber, caster, and steer angles.

  • Bounce test– Independent suspension

  • Roll test– Independent suspension

  • Steer test

  • Longitudinal compliance test

  • Lateral compliance-opposed test

  • Aligning torque compliance-opposed test

Use the Static alignment settings parameters to set the initial state of the suspension.

Lateral Wheel Center Displacement

The block uses these parameters to account for the K and C effects the lateral wheel center displacement.

  • Bounce test

  • Longitudinal compliance test

  • Lateral compliance-opposed test

Longitudinal Wheel Center Displacement

The block uses these parameters to account for the K and C effects on the longitudinal wheel center displacement.

  • Bounce test

  • Longitudinal compliance test

Shock Force

The block uses the Shock force parameters to calculate the shock force effect on the vertical suspension force. You can specify table-based or constant parameter values.

Wheel Rate

The block uses the Bounce test parameters to calculate the wheel rate effect on the vertical suspension force.

Contact Patch Swing Arm

The block uses these equations to calculate the effect of the contact patch swing arm (CPSA) forces on vertical suspension force.

tan(θCPSA)=f(Zw)FzCPSA=Fytan(θCPSA)

The block also uses the Static loaded radius of wheels parameter in the CPSA force calculation.

The equations use these variables.

ϴCPSA

Contact patch swing arm angle

Fy

Lateral suspension force

FzCPSA

CPSA effect on vertical suspension force

zw

Wheel displacement

Longitudinal Side View Swing Arm Anti-Effects

The block uses these equations to calculate the effect of the side view swing arm (SVSA) forces on vertical suspension force during acceleration and braking.

tan(θSVSA)=f(Zw)FzSVSA=Fxtan(θSVSA)

Use the Drivetrain type parameter to ensure that the block applies the acceleration anti-effects to the correct wheels.

The equations use these variables.

ϴSVSA

Contact patch swing arm angle

Fx

Longitudinal wheel force

FzSVSA

SVSA effect on vertical suspension force

zw

Wheel displacement

Anti-Sway Bar

Optionally, use the Anti-sway axle enable by axle, AntiSwayEnByAxl parameter to implement anti-sway bar reaction forces by axle.

If you enable an anti-sway bar on the axle, the anti-sway bar stiffness is the difference between the anti-sway bar torque parameter, Suspension roll stiffness with anti-roll bar, RollStiffArb, and the roll stiffness parameter measured with no anti-sway bar present Suspension roll stiffness without anti-roll bar, RollStiffNoArb.

If you do not enable an anti-sway bar, the roll stiffness is 0.

Ports

The block uses the wheel number, t, to index the input and output signals. This table summarizes the wheel, axle, and corresponding wheel number for a vehicle with:

  • Two axles

  • Two wheels per axle

WheelAxleWheel Number
Front leftFront1
Front rightFront2
Rear leftRear1
Rear rightRear2

Input

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Wheel displacement, zw, along wheel-fixed z-axis, in m. Array dimensions are 1 by the total number of wheels on the vehicle.

For example, for a two-axle vehicle with two wheels per axle, the WhlPz:

  • Signal array dimensions are [1x4].

    WhlPz=zw=[zw1,1zw1,2zw2,1zw2,2]

    WheelArray ElementAxleWheel Number
    Front leftWhlPz(1,1)11
    Front rightWhlPz(1,2)12
    Rear leftWhlPz(1,3)21
    Rear rightWhlPz(1,4)22

Effective wheel radius, Rew, in m. Array dimensions are 1 by the total number of wheels on the vehicle.

For example, for a two-axle vehicle with two wheels per axle, the WhlRe:

  • Signal array dimensions are [1x4].

    WhlRe=Rew=[Rew1,1Rew1,2Rew2,1Rew2,2]

    WheelArray ElementAxleWheel Number
    Front leftWhlRe(1,1)11
    Front rightWhlRe(1,2)12
    Rear leftWhlRe(1,3)21
    Rear rightWhlRe(1,4)22

Wheel velocity, żw, along wheel-fixed z-axis, in m. Array dimensions are 1 by the total number of wheels on the vehicle.

For example, for a two-axle vehicle with two wheels per axle, the WhlVz:

  • Signal array dimensions are [1x4].

    WhlVz=z˙w=[z˙w1,1z˙w1,2z˙w2,1z˙w2,2]

    WheelArray ElementAxleWheel Number
    Front leftWhlVz(1,1)11
    Front rightWhlVz(1,2)12
    Rear leftWhlVz(1,3)21
    Rear rightWhlVz(1,4)22

Longitudinal wheel force applied to vehicle, Fwx, along the vehicle-fixed x-axis. Array dimensions are 1 by the total number of wheels on the vehicle.

For example, for a two-axle vehicle with two wheels per axle, the WhlFx:

  • Signal array dimensions are [1x4].

    WhlFx=Fwx=[Fwx1,1Fwx1,2Fwx2,1Fwx2,2]

    WheelArray ElementAxleWheel Number
    Front leftWhlFx(1,1)11
    Front rightWhlFx(1,2)12
    Rear leftWhlFx(1,3)21
    Rear rightWhlFx(1,4)22

Lateral wheel force applied to vehicle, Fwy, along the vehicle-fixed y-axis. Array dimensions are 1 by the total number of wheels on the vehicle.

For example, for a two-axle vehicle with two wheels per axle, the WhlFy:

  • Signal array dimensions are [1x4].

    WhlFy=Fwy=[Fwy1,1Fwy1,2Fwy2,1Fwy2,2]

    WheelArray ElementAxleWheel Number
    Front leftWhlFy(1,1)11
    Front rightWhlFy(1,2)12
    Rear leftWhlFy(1.3)21
    Rear rightWhlFy(1,4)22

Longitudinal, lateral, and vertical suspension moments at axle a, wheel t, applied to the wheel at the axle wheel carrier reference coordinate, in N·m. Input array dimensions are 3 by the number of wheels on the vehicle.

  • WhlM(1,...) — Suspension moment applied to the wheel about the vehicle-fixed x-axis (longitudinal)

  • WhlM(2,...) — Suspension moment applied to the wheel about the vehicle-fixed y-axis (lateral)

  • WhlM(3,...) — Suspension moment applied to the wheel about the vehicle-fixed z-axis (vertical)

For example, for a two-axle vehicle with two wheels per axle, the WhlM:

  • Signal dimensions are [3x4].

  • Signal contains suspension moments applied to four wheels according to their axle and wheel locations.

    WhlM=Mw=[Mwx1,1Mwx1,2Mwx2,1Mwx2,2Mwy1,1Mwy1,2Mwy2,1Mwy2,2Mwz1,1Mwz1,2Mwz2,1Mwz2,2]

    WheelArray ElementAxleWheel NumberMoment Axis
    Front leftWhlM(1,1)11Vehicle-fixed x-axis (longitudinal)
    Front rightWhlM(1,2)12
    Rear leftWhlM(1,3)21
    Rear rightWhlM(1,4)22
    Front leftWhlM(2,1)11Vehicle-fixed y-axis (lateral)
    Front rightWhlM(2,2)12
    Rear leftWhlM(2,3)21
    Rear rightWhlM(2,4)22
    Front leftWhlM(3,1)11Vehicle-fixed z-axis (vertical)
    Front rightWhlM(3,2)12
    Rear leftWhlM(3,3)21
    Rear rightWhlM(3,4)22

Vehicle displacement from axle a, wheel t along vehicle-fixed coordinate system, in m. Input array dimensions are 3 the number of wheels on the vehicle.

  • VehP(1,...) — Vehicle displacement from wheel, xv, along the vehicle-fixed x-axis

  • VehP(2,...) — Vehicle displacement from wheel, yv, along the vehicle-fixed y-axis

  • VehP(3,...) — Vehicle displacement from wheel, zv, along the vehicle-fixed z-axis

For example, for a two-axle vehicle with two wheels per axle, the VehP:

  • Signal dimensions are [3x4].

  • Signal contains four displacements according to their axle and wheel locations.

    VehP=[xvyvzv]=[xv1,1xv1,2xv2,1xv2,2yv1,1yv1,2yv2,1yv2,2zv1,1zv1,2zv2,1zv2,2]

    WheelArray ElementAxleWheel NumberAxis
    Front leftVehP(1,1)11Vehicle-fixed x-axis
    Front rightVehP(1,2)12
    Rear leftVehP(1,3)21
    Rear rightVehP(1,4)22
    Front leftVehP(2,1)11Vehicle-fixed y-axis
    Front rightVehP(2,2)12
    Rear leftVehP(2,3)21
    Rear rightVehP(2,4)22
    Front leftVehP(3,1)11Vehicle-fixed z-axis
    Front rightVehP(3,2)12
    Rear leftVehP(3,3)21
    Rear rightVehP(3,4)22

Vehicle velocity at axle a, wheel t along vehicle-fixed coordinate system, in m. Input array dimensions are 3 by the number of wheels on the vehicle.

  • VehV(1,...) — Vehicle velocity at wheel, xv, along the vehicle-fixed x-axis

  • VehV(2,...) — Vehicle velocity at wheel, yv, along the vehicle-fixed y-axis

  • VehV(3,...) — Vehicle velocity at wheel, zv, along the vehicle-fixed z-axis

For example, for a two-axle vehicle with two wheels per axle, the VehV:

  • Signal dimensions are [3x4].

  • Signal contains 4 velocities according to their axle and wheel locations.

    VehV=[x˙vy˙vz˙v]=[x˙v1,1x˙v1,2x˙v2,1x˙v2,2y˙v1,1y˙v1,2y˙v2,1y˙v2,2z˙v1,1z˙v1,2z˙v2,1z˙v2,2]

    WheelArray ElementAxleWheel NumberAxis
    Front leftVehV(1,1)11Vehicle-fixed x-axis
    Front rightVehV(1,2)12
    Rear leftVehV(1,3)21
    Rear rightVehV(1,4)22
    Front leftVehV(2,1)11Vehicle-fixed y-axis
    Front rightVehV(2,2)12
    Rear leftVehV(2,3)21
    Rear rightVehV(2,4)22
    Front leftVehV(3,1)11Vehicle-fixed z-axis
    Front rightVehV(3,2)12
    Rear leftVehV(3,3)21
    Rear rightVehV(3,4)22

Optional steering angle for each wheel, δ. Input array dimensions are 1 by the number of steered wheels.

For example, for a two-axle vehicle with two wheels per axle, you can input steering angles for both wheels on the first axle.

  • To create the StrgAng port, set Steered axle enable by axle, StrgEnByAxl to [1 0]. The input signal array dimensions are [1x2].

  • The StrgAng signal contains two steering angles according to their axle and wheel locations.

    StrgAng=δsteer=[δsteer1,1δsteer1,2]

    WheelArray ElementAxleWheel Number
    Front leftStrgAng(1,1)11
    Front rightStrgAng(1,2)12

Dependencies

To create input port StrgAng, set an element of the Steered axle enable by axle, StrgEnByAxl vector to 1.

Vehicle pitch angle about earth-fixed Y-axis, in rad.

Distance between wheels on each axle. Input array dimensions are 1-by-2.

Array ElementDescription
TrckWdth(1,1)Distance between wheels on front axle
TrckWdth(1,2)Distance between wheels on rear axle

Output

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Bus signal containing block values. The signals are arrays that depend on the wheel location.

For example, here are the indices for a two-axle, two-wheel vehicle. The total number of wheels is four.

  • 1D array signal (1-by-4)

    WheelArray ElementAxleWheel Number
    Front left(1,1)11
    Front right(1,2)12
    Rear left(1,3)21
    Rear right(1,4)22

  • 3D array signal (3-by-4)

    WheelArray ElementAxleWheel Number
    Front left(1,1)11
    Front right(1,2)12
    Rear left(1,3)21
    Rear right(1,4)22
    Front left(2,1)11
    Front right(2,2)12
    Rear left(2,3)21
    Rear right(2,4)22
    Front left(3,1)11
    Front right(3,2)12
    Rear left(3,3)21
    Rear right(3,4)22

SignalDescriptionArray SignalVariableUnits
Camber

Wheel angles according to the axle and wheel location.

1D

WhlAng[1,...]=ξ=[ξa,t]

rad

Caster

WhlAng[2,...]=η=[ηa,t]

Toe

WhlAng[3,...]=ζ=[ζa,t]

Height

Suspension height

1D

H

m

Power

Suspension power dissipation

1D

Psusp

W

Energy

Suspension absorbed energy

1D

Esusp

J

VehF

Suspension forces applied to the vehicle

3D

For a two-axle, two wheels per axle vehicle:

VehF=Fv=[Fvx1,1Fvx1,2Fvx2,1Fvx2,2Fvy1,1Fvy1,2Fvy2,1Fvy2,2Fvz1,1Fvz1,2Fvz2,1Fvz2,2]

N

VehM

Suspension moments applied to vehicle

3D

For a two-axle, two wheels per axle vehicle:

VehM=Mv=[Mvx1,1Mvx1,2Mvx2,1Mvx2,2Mvy1,1Mvy1,2Mvy2,1Mvy2,2Mvz1,1Mvz1,2Mvz2,1Mvz2,2]

N·m

WhlF

Suspension force applied to wheel

3D

For a two-axle, two wheels per axle vehicle:

WhlF=Fw=[Fwx1,1Fwx1,2Fwx2,1Fwx2,2Fwy1,1Fwy1,2Fwy2,1Fwy2,2Fwz1,1Fwz1,2Fwz2,1Fwz2,2]

N

WhlP

Wheel displacement

3D

For a two-axle, two wheels per axle vehicle:

WhlP=[xwywzw]=[xw1,1xw1,2xw2,1xw2,2yw1,1yw1,2yw2,1ywy2,2zwtr1,1zwtr1,2zwtr2,1zwtr2,2]

m

WhlV

Wheel velocity

3D

For a two-axle, two wheels per axle vehicle:

WhlV=[x˙wy˙wz˙w]=[x˙w1,1x˙w1,2x˙w2,1x˙w2,2y˙w1,1y˙w1,2y˙w2,1y˙w2,2z˙w1,1z˙w1,2z˙w2,1z˙w2,2]

m/s

WhlAng

Wheel camber, caster, toe angles

3D

For a two-axle, two wheels per axle vehicle:

WhlAng=[ξηζ]=[ξ1,1ξ1,2ξ2,1ξ2,2η1,1η1,2η2,1η2,2ζ1,1ζ1,2ζ2,1ζ2,2]

rad

Longitudinal, lateral, and vertical suspension force at axle a, wheel t, applied to the vehicle at the suspension connection point, in N. Array dimensions are 3 by the number of wheels on the vehicle.

  • VehF(1,...) — Suspension force applied to vehicle along the vehicle-fixed x-axis (longitudinal)

  • VehF(2,...) — Suspension force applied to vehicle along the vehicle-fixed y-axis (lateral)

  • VehF(3,...) — Suspension force applied to vehicle along the vehicle-fixed z-axis (vertical)

For example, for a two-axle vehicle with two wheels per axle, the VehF:

  • Signal dimensions are [3x4].

  • Signal contains suspension forces applied to the vehicle according to the axle and wheel locations.

    VehF=Fv=[Fvx1,1Fvx1,2Fvx2,1Fvx2,2Fvy1,1Fvy1,2Fvy2,1Fvy2,2Fvz1,1Fvz1,2Fvz2,1Fvz2,2]

    WheelArray ElementAxleWheel NumberForce Axis
    Front leftVehF(1,1)11Vehicle-fixed x-axis (longitudinal)
    Front rightVehF(1,2)12
    Rear leftVehF(1,3)21
    Rear rightVehF(1,4)22
    Front leftVehF(2,1)11Vehicle-fixed y-axis (lateral)
    Front rightVehF(2,2)12
    Rear leftVehF(2,3)21
    Rear rightVehF(2,4)22
    Front leftVehF(3,1)11Vehicle-fixed z-axis (vertical)
    Front rightVehF(3,2)12
    Rear leftVehF(3,3)21
    Rear rightVehF(3,4)22

Longitudinal, lateral, and vertical suspension moment at axle a, wheel t, applied to the vehicle at the suspension connection point, in N·m. Array dimensions are 3 by the number of wheels on the vehicle.

  • VehM(1,...) — Suspension moment applied to the vehicle about the vehicle-fixed x-axis (longitudinal)

  • VehM(2,...) — Suspension moment applied to the vehicle about the vehicle-fixed y-axis (lateral)

  • VehM(3,...) — Suspension moment applied to the vehicle about the vehicle-fixed z-axis (vertical)

For example, for a two-axle vehicle with two wheels per axle, the VehM:

  • Signal dimensions are [3x4].

  • Signal contains suspension moments applied to vehicle according to the axle and wheel locations.

    VehM=Mv=[Mvx1,1Mvx1,2Mvx2,1Mvx2,2Mvy1,1Mvy1,2Mvy2,1Mvy2,2Mvz1,1Mvz1,2Mvz2,1Mvz2,2]

    Array ElementAxleWheel NumberMoment Axis
    VehM(1,1)11Vehicle-fixed x-axis (longitudinal)
    VehM(1,2)12
    VehM(1,3)21
    VehM(1,4)22
    VehM(2,1)11Vehicle-fixed y-axis (lateral)
    VehM(2,2)12
    VehM(2,3)21
    VehM(2,4)22
    VehM(3,1)11Vehicle-fixed z-axis (vertical)
    VehM(3,2)12
    VehM(3,3)21
    VehM(3,4)22

Longitudinal, lateral, and vertical suspension forces at axle a, wheel t, applied to the wheel at the axle wheel carrier reference coordinate, in N. Array dimensions are 3 by the number of wheels on the vehicle.

  • WhlF(1,...) — Suspension force on wheel along the vehicle-fixed x-axis (longitudinal)

  • WhlF(2,...) — Suspension force on wheel along the vehicle-fixed y-axis (lateral)

  • WhlF(3,...) — Suspension force on wheel along the vehicle-fixed z-axis (vertical)

For example, for a two-axle vehicle with two wheels per axle, the WhlF:

  • Signal dimensions are [3x4].

  • Signal contains wheel forces applied to the vehicle according to the axle and wheel locations.

    WhlF=Fw=[Fwx1,1Fwx1,2Fwx2,1Fwx2,2Fwy1,1Fwy1,2Fwy2,1Fwy2,2Fwz1,1Fwz1,2Fwz2,1Fwz2,2]

    WheelArray ElementAxleWheel NumberForce Axis
    Front leftWhlF(1,1)11Vehicle-fixed x-axis (longitudinal)
    Front rightWhlF(1,2)12
    Rear leftWhlF(1,3)21
    Rear rightWhlF(1,4)22
    Front leftWhlF(2,1)11Vehicle-fixed y-axis (lateral)
    Front rightWhlF(2,2)12
    Rear leftWhlF(2,3)21
    Rear rightWhlF(2,4)22
    Front leftWhlF(3,1)11Vehicle-fixed z-axis (vertical)
    Front rightWhlF(3,2)12
    Rear leftWhlF(3,3)21
    Rear rightWhlF(3,4)22

Longitudinal, lateral, and vertical wheel velocity at axle a, wheel t, in m/s. Array dimensions are 3 by the number of wheels on the vehicle.

  • WhlV(1,...) — Wheel velocity along the vehicle-fixed x-axis (longitudinal)

  • WhlV(2,...) — Wheel velocity along the vehicle-fixed y-axis (lateral)

  • WhlV(3,...) — Wheel velocity along the vehicle-fixed z-axis (vertical)

For example, for a two-axle vehicle with two wheels per axle, the WhlV:

  • Signal dimensions are [3x4].

  • Signal contains wheel forces applied to the vehicle according to the axle and wheel locations.

    WhlV=[x˙wy˙wz˙w]=[x˙w1,1x˙w1,2x˙w2,1x˙w2,2y˙w1,1y˙w1,2y˙w2,1y˙w2,2z˙w1,1z˙w1,2z˙w2,1z˙w2,2]

    WheelArray ElementAxleWheel NumberForce Axis
    Front leftWhlV(1,1)11Vehicle-fixed x-axis (longitudinal)
    Front rightWhlV(1,2)12
    Rear leftWhlV(1,3)21
    Rear rightWhlV(1,4)22
    Front leftWhlV(2,1)11Vehicle-fixed y-axis (lateral)
    Front rightWhlV(2,2)12
    Rear leftWhlV(2,3)21
    Rear rightWhlV(2,4)22
    Front leftWhlV(3,1)11Vehicle-fixed z-axis (vertical)
    Front rightWhlV(3,2)12
    Rear leftWhlV(3,3)21
    Rear rightWhlV(3,4)22

Camber, caster, and toe angles at axle a, wheel t, in rad. Array dimensions are 3 by the number of wheels on the vehicle.

  • WhlAng(1,...) — Camber angle

  • WhlAng(2,...) — Caster angle

  • WhlAng(3,...) — Toe angle

For example, for a two-axle vehicle with two wheels per axle, the WhlAng:

  • Signal dimensions are [3x4].

  • Signal contains angles according to the axle and wheel locations.

    WhlAng=[ξηζ]=[ξ1,1ξ1,2ξ2,1ξ2,2η1,1η1,2η2,1η2,2ζ1,1ζ1,2ζ2,1ζ2,2]

    WheelArray ElementAxleWheel NumberAngle
    Front leftWhlAng(1,1)11

    Camber

    Front rightWhlAng(1,2)12
    Rear leftWhlAng(1,3)21
    Rear rightWhlAng(1,4)22
    Front leftWhlAng(2,1)11

    Caster

    Front rightWhlAng(2,2)12
    Rear leftWhlAng(2,3)21
    Rear rightWhlAng(2,4)22
    Front leftWhlAng(3,1)11

    Toe

    Front rightWhlF(3,2)12
    Rear leftWhlF(3,3)21
    Rear rightWhlF(3,4)22

Parameters

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Boolean vector that enables axle steering, Ensteer, dimensionless. Vector is 1 by the number of vehicle axles, Na. For example:

  • [1 0] — For a two-axle vehicle, enables axle 1 steering and disables axle 2 steering

  • [1 1] — For a two-axle vehicle, enables axle 1 and axle 2 steering

Dependencies

Setting any element of the Steered axle enable by axle, StrgEnByAxl vector to 1 creates Input port StrgAng.

Boolean vector that enables axle anti-sway for axle a, dimensionless. For example, [1 0] enables axle 1 anti-sway and disables axle 2 anti-sway. Vector is 1 by the number of vehicle axles, Na.

If you enable an anti-sway bar on the axle, the anti-sway bar stiffness is the difference between the anti-sway bar torque parameter, Suspension roll stiffness with anti-roll bar, RollStiffArb, and the roll stiffness parameter measured with no anti-sway bar present Suspension roll stiffness without anti-roll bar, RollStiffNoArb.

If you do not enable an anti-sway bar, the stiffness is 0.

Suspension Parameters

Select type of suspension.

Select type of drivetrain.

  • AWD – All-wheel drive

  • FWD – Front-wheel drive

  • RWD – Rear-wheel drive

Directions

Direction of positive steer angle during kinematics and compliance test.

Direction of positive longitudinal force during kinematics and compliance test.

Direction of positive lateral force during kinematics and compliance test.

Direction of positive suspension jounce during kinematics and compliance test.

Direction of positive yaw moment during kinematics and compliance test.

Shock force

Type of shock force.

If a table-based individual setting is chosen, table-based shock force is implemented together with constant motion ratios. If a table-based setting is chosen both shock force and motion ratios are calculated from lookup tables.

SettingImplementation
Table-based

Table-based shock force and motion ratios.

Table-based individual

Table-based shock force and constant motion ratios.

Constant

Constant shock force and motion ratios.

Shock force versus shock compression rate, specified as a structure, in N/mm per sec.

Dependencies

To create this parameter, set Shock type to Table-based or Table-based individual.

Data Types: struct

Motion ratios by axle, specified as a structure.

Data Types: struct

Bounce test

Bump steer, specified as a structure, in deg/m.

Data Types: struct

Bump camber, specified as a structure, in deg/m.

Data Types: struct

Bump caster, specified as a structure, in deg/m.

Data Types: struct

Lateral wheel center displacement, specified as a structure, in mm/mm.

Data Types: struct

Longitudinal wheel center displacement, specified as a structure, in mm/mm.

Data Types: struct

Normal wheel rates, specified as a structure, in N/mm.

Data Types: struct

Normal wheel force offsets, specified as a vector, in N.

Dependencies

To create this parameter, specify a Normal wheel rates, NrmlWhlRates vector.

Data Types: struct

Roll test

Suspension roll stiffness with anti-roll bar, specified as a 1-by-2 vector, in Nm/deg. The first element is the front axle roll stiffness. The second element is the rear axle roll stiffness.

If you enable an anti-sway bar on the axle, the anti-sway bar stiffness is the difference between the anti-sway bar torque parameter, Suspension roll stiffness with anti-roll bar, RollStiffArb, and the roll stiffness parameter measured with no anti-sway bar present Suspension roll stiffness without anti-roll bar, RollStiffNoArb.

If you do not enable an anti-sway bar, the stiffness is 0.

Dependencies

To enable this parameter, set Suspension type to Independent front and rear.

Data Types: double

Suspension roll stiffness without anti-roll bar, specified as a 1-by-2 vector, in Nm/deg. The first element is the front axle roll stiffness. The second element is the rear axle roll stiffness.

If you enable an anti-sway bar on the axle, the anti-sway bar stiffness is the difference between the anti-sway bar torque parameter, Suspension roll stiffness with anti-roll bar, RollStiffArb, and the roll stiffness parameter measured with no anti-sway bar present Suspension roll stiffness without anti-roll bar, RollStiffNoArb.

If you do not enable an anti-sway bar, the stiffness is 0.

Dependencies

To enable this parameter, set Suspension type to Independent front and rear.

Data Types: double

Steer test

Camber vs steer angle, specified as a structure, in deg/deg.

Data Types: struct

Caster vs steer angle, specified as a structure, in deg/deg.

Data Types: struct

Longitudinal compliance test

Longitudinal steer compliance, specified as a structure, in deg/kN.

Data Types: struct

Longitudinal camber compliance, specified as a structure, in deg/kN.

Data Types: struct

Longitudinal caster compliance, specified as a structure, in deg/kN.

Data Types: struct

Longitudinal wheel center compliance, specified as a structure, in mm/kN.

Data Types: struct

Lateral wheel center compliance from braking, specified as a structure, in mm/kN.

Data Types: struct

Lateral compliance-opposed test

Lateral steer compliance, specified as a structure, in deg/kN.

Data Types: struct

Lateral camber compliance, specified as a structure, in deg/kN.

Data Types: struct

Lateral wheel center compliance from lateral sources, specified as a structure, in mm/kN.

Data Types: struct

Aligning torque compliance-opposed test

Aligning torque steer compliance, specified as a structure, in deg/kNm.

Data Types: struct

Aligning torque camber compliance, specified as a structure, in deg/kNm.

Data Types: struct

Static alignment settings

Static toe angle for each wheel, specified as a 1-by-4 vector, in deg.

WheelArray ElementAxleWheel Location
Front left(1,1)11
Front right(1,2)12
Rear left(1,3)21
Rear left(1,4)22

Data Types: double

Static camber angle for each wheel, specified as a 1-by-4 vector, in deg.

WheelArray ElementAxle
Front left(1,1)1
Front right(1,2)1
Rear left(1,3)2
Rear left(1,4)2

Data Types: double

Static caster angle for each wheel, specified as a 1-by-4 vector, in deg.

WheelArray ElementAxle
Front left(1,1)1
Front right(1,2)1
Rear left(1,3)2
Rear left(1,4)2

Data Types: double

Wheels

Static loaded radius of wheels, specified as a 1-by-4 vector, in m.

WheelArray ElementAxle
Front left(1,1)1
Front right(1,2)1
Rear left(1,3)2
Rear left(1,4)2

Data Types: double

References

[1] Gillespie, Thomas. Fundamentals of Vehicle Dynamics. Warrendale, PA: Society of Automotive Engineers, 1992.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2022a

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