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Independent Suspension - K and C

Kinematics and compliance test suspension

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  • Vehicle Dynamics Blockset / Suspension

  • Independent Suspension - K and C block

Description

The Independent Suspension - K and C block implements the kinematics and compliance (K and C) test suspension characteristics measured from simulated or actual laboratory suspension tests. The block models the kinematics and compliance effects of four independent suspensions on a vehicle with two axles and two tracks per axle. You can specify positive directions for steer angles, forces, jounce, and moments

The block parameters correspond to these standard kinematics and compliance test measurements:

  • Shock force

  • Bounce, roll, and steer tests

  • Longitudinal compliance braking test

  • Lateral and aligning torque compliance-opposed test

The block uses standard kinematics and compliance test parameters to calculate:

  • Wheel orientation changes due to suspension displacement and applied loads.

  • Suspension forces on the vehicle and wheels.

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 effect of each suspension movement, including bounce, roll, and steering. Specifically, the block multiplies the suspension geometry states by either constant or table values to determine these individual effects on the suspension forces and geometry:

  • Anti-sway bar

  • Camber, caster, and toe angles

  • Lateral wheel center compliance

  • Longitudinal wheel center compliance

  • Shock force

  • Wheel rate

  • Contact patch swing arm (CPSA) force

Anti-Sway Bar

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

The anti-sway bar reaction force 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-roll bar present Suspension roll stiffness without anti-roll bar, RollStiffNoArb.

Camber, Caster, and Toe Angles

The block uses these parameters to account for the effect of bounce, roll, and steering inputs on the camber, caster, and toe angles.

  • Bounce test

  • Steer test

  • Longitudinal compliance braking test

  • Lateral compliance-opposed braking test

  • Aligning torque compliance-opposed braking test

To offset the camber, caster and toe angles, use the Static alignment settings parameters.

Lateral Wheel Center Compliance

The block uses these parameters to account for the effect of bounce, roll, and steering inputs on the Lateral wheel center compliance.

  • Bounce test

  • Longitudinal compliance braking test

  • Lateral compliance-opposed braking test

Longitudinal Wheel Center Compliance

The block uses these parameters to account for the effect of bounce, roll, and steering inputs on the longitudinal wheel center compliance.

  • Bounce test

  • Longitudinal compliance braking test

Shock Force

The block uses the Shock force parameters to account for the effect of bounce, roll, and steering inputs on the vertical suspension force. You can specify table-based or constant parameter values.

Wheel Rate

The block uses the Bounce test parameters to account for the effect of bounce, roll, and steering inputs on the suspension.

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.

θw=f(Zw)FzCPSA=Fyθw

The equations use these variables.

ϴw

Track angle displacement due to vertical displacement at contact patch

Fy

Lateral suspension force

FzCPSA

CPSA effect on vertical suspension force

zw

Track displacement

Ports

Input

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

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

  • Signal array dimensions are [1x4].

  • Array dimensions are axle by track.

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

    Array ElementAxleTrack
    WhlPz(1,1)11
    WhlPz(1,2)12
    WhlPz(1,3)21
    WhlPz(1,4)22

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

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

  • Signal array dimensions are [1x4].

  • Array dimensions are axle by track.

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

    Array ElementAxleTrack
    WhlRe(1,1)11
    WhlRe(1,2)12
    WhlRe(1,3)21
    WhlRe(1,4)22

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

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

  • Signal array dimensions are [1x4].

  • Array dimensions are axle by track.

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

    Array ElementAxleTrack
    WhlVz(1,1)11
    WhlVz(1,2)12
    WhlVz(1,3)21
    WhlVz(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 tracks on the vehicle.

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

  • Signal array dimensions are [1x4].

  • Array dimensions are axle by track.

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

    Array ElementAxleTrack
    WhlFx(1,1)11
    WhlFx(1,2)12
    WhlFx(1,3)21
    WhlFx(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 tracks on the vehicle.

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

  • Signal array dimensions are [1x4].

  • Array dimensions are axle by track.

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

    Array ElementAxleTrack
    WhlFy(1,1)11
    WhlFy(1,2)12
    WhlFy(1.3)21
    WhlFy(1,4)22

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

  • 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 tracks per axle, the WhlM:

  • Signal dimensions are [3x4].

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

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

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

Vehicle displacement from axle a, track t along vehicle-fixed coordinate system, in m. Input array dimensions are 3 by a*t.

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

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

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

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

  • Signal dimensions are [3x4].

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

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

    Array ElementAxleTrackAxis
    VehP(1,1)11Vehicle-fixed x-axis
    VehP(1,2)12
    VehP(1,3)21
    VehP(1,4)22
    VehP(2,1)11Vehicle-fixed y-axis
    VehP(2,2)12
    VehP(2,3)21
    VehP(2,4)22
    VehP(3,1)11Vehicle-fixed z-axis
    VehP(3,2)12
    VehP(3,3)21
    VehP(3,4)22

Vehicle velocity at axle a, track t along vehicle-fixed coordinate system, in m. Input array dimensions are 3 by a*t.

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

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

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

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

  • Signal dimensions are [3x4].

  • Signal contains 4 track velocities according to their axle and track 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]

    Array ElementAxleTrackAxis
    VehV(1,1)11Vehicle-fixed x-axis
    VehV(1,2)12
    VehV(1,3)21
    VehV(1,4)22
    VehV(2,1)11Vehicle-fixed y-axis
    VehV(2,2)12
    VehV(2,3)21
    VehV(2,4)22
    VehV(3,1)11Vehicle-fixed z-axis
    VehV(3,2)12
    VehV(3,3)21
    VehV(3,4)22

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

For example, for a two-axle vehicle with two tracks 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 track locations.

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

    Array ElementAxleTrack
    StrgAng(1,1)11
    StrgAng(1,2)12

Dependencies

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

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

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

  • Signal array dimensions are [1x4].

  • Array dimensions are axle by track.

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

    Array ElementAxleTrack
    WhlPz(1,1)11
    WhlPz(1,2)12
    WhlPz(1,3)21
    WhlPz(1,4)22

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

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

  • Signal array dimensions are [1x4].

  • Array dimensions are axle by track.

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

    Array ElementAxleTrack
    WhlRe(1,1)11
    WhlRe(1,2)12
    WhlRe(1,3)21
    WhlRe(1,4)22

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

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

  • Signal array dimensions are [1x4].

  • Array dimensions are axle by track.

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

    Array ElementAxleTrack
    WhlVz(1,1)11
    WhlVz(1,2)12
    WhlVz(1,3)21
    WhlVz(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 tracks on the vehicle.

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

  • Signal array dimensions are [1x4].

  • Array dimensions are axle by track.

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

    Array ElementAxleTrack
    WhlFx(1,1)11
    WhlFx(1,2)12
    WhlFx(1,3)21
    WhlFx(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 tracks on the vehicle.

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

  • Signal array dimensions are [1x4].

  • Array dimensions are axle by track.

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

    Array ElementAxleTrack
    WhlFy(1,1)11
    WhlFy(1,2)12
    WhlFy(1.3)21
    WhlFy(1,4)22

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

  • 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 tracks per axle, the WhlM:

  • Signal dimensions are [3x4].

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

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

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

Vehicle displacement from axle a, track t along vehicle-fixed coordinate system, in m. Input array dimensions are 3 by a*t.

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

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

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

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

  • Signal dimensions are [3x4].

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

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

    Array ElementAxleTrackAxis
    VehP(1,1)11Vehicle-fixed x-axis
    VehP(1,2)12
    VehP(1,3)21
    VehP(1,4)22
    VehP(2,1)11Vehicle-fixed y-axis
    VehP(2,2)12
    VehP(2,3)21
    VehP(2,4)22
    VehP(3,1)11Vehicle-fixed z-axis
    VehP(3,2)12
    VehP(3,3)21
    VehP(3,4)22

Vehicle velocity at axle a, track t along vehicle-fixed coordinate system, in m. Input array dimensions are 3 by a*t.

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

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

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

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

  • Signal dimensions are [3x4].

  • Signal contains 4 track velocities according to their axle and track 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]

    Array ElementAxleTrackAxis
    VehV(1,1)11Vehicle-fixed x-axis
    VehV(1,2)12
    VehV(1,3)21
    VehV(1,4)22
    VehV(2,1)11Vehicle-fixed y-axis
    VehV(2,2)12
    VehV(2,3)21
    VehV(2,4)22
    VehV(3,1)11Vehicle-fixed z-axis
    VehV(3,2)12
    VehV(3,3)21
    VehV(3,4)22

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

For example, for a two-axle vehicle with two tracks 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 track locations.

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

    Array ElementAxleTrack
    StrgAng(1,1)11
    StrgAng(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.

Track width. Input array dimensions are 1-by-2.

Array ElementDescription
TrckWdth(1,1)Front axle track width
TrckWdth(1,2)Rear axle track width

Output

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

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

  • 1D array signal (1-by-4)

    Array ElementAxleTrack
    (1,1)11
    (1,2)12
    (1,3)21
    (1,4)22

  • 3D array signal (3-by-4)

    Array ElementAxleTrack
    (1,1)11
    (1,2)12
    (1,3)21
    (1,4)22
    (2,1)11
    (2,2)12
    (2,3)21
    (2,4)22
    (3,1)11
    (3,2)12
    (3,3)21
    (3,4)22

SignalDescriptionArray SignalVariableUnits
Camber

Wheel angles according to the axle and track 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 tracks 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 tracks 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 tracks per axle vehicle:

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

N

WhlP

Track displacement

3D

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

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

m

WhlV

Track velocity

3D

For a two-axle, two tracks 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 tracks 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, track t, applied to the vehicle at the suspension connection point, in N. Array dimensions are 3 by a*t.

  • 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 tracks per axle, the VehF:

  • Signal dimensions are [3x4].

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

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

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

Longitudinal, lateral, and vertical suspension moment at axle a, track t, applied to the vehicle at the suspension connection point, in N·m. Array dimensions are 3 by a*t.

  • 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 tracks per axle, the VehM:

  • Signal dimensions are [3x4].

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

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

    Array ElementAxleTrackMoment 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, track t, applied to the wheel at the axle wheel carrier reference coordinate, in N. Array dimensions are 3 by a*t.

  • 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 tracks per axle, the WhlF:

  • Signal dimensions are [3x4].

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

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

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

Longitudinal, lateral, and vertical track velocity at axle a, track t, in m/s. Array dimensions are 3 by a*t.

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

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

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

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

  • Signal dimensions are [3x4].

  • Signal contains wheel forces applied to the vehicle according to the axle and track 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]

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

Camber, caster, and toe angles at axle a, track t, in rad. Array dimensions are 3 by a*t.

  • WhlAng(1,...) — Camber angle

  • WhlAng(2,...) — Caster angle

  • WhlAng(3,...) — Toe angle

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

  • Signal dimensions are [3x4].

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

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

    Array ElementAxleTrackAngle
    WhlAng(1,1)11

    Camber

    WhlAng(1,2)12
    WhlAng(1,3)21
    WhlAng(1,4)22
    WhlAng(2,1)11

    Caster

    WhlAng(2,2)12
    WhlAng(2,3)21
    WhlAng(2,4)22
    WhlAng(3,1)11

    Toe

    WhlF(3,2)12
    WhlF(3,3)21
    WhlF(3,4)22

Parameters

expand all

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.

Dependencies

This table provides the parameter that the block uses for the roll bar stiffness.

Anti-Sway Enable

Roll Bar Stiffness

1 — trueSuspension roll stiffness with anti-roll bar, RollStiffArb
0 — falseSuspension roll stiffness without anti-roll bar, RollStiffNoArb

Suspension Parameters

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.

Dependencies

If Anti-sway axle enable by axle, AntiSwayEnByAxl is enabled for an axle, the block uses this parameter for the roll stiffness.

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.

Dependencies

If Anti-sway axle enable by axle, AntiSwayEnByAxl is not enabled for an axle, the block uses this for the roll stiffness.

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 braking 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 braking 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 braking 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 ElementAxleTrack
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 ElementAxleTrack
Front left(1,1)11
Front right(1,2)12
Rear left(1,3)21
Rear left(1,4)22

Data Types: double

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

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

Data Types: double

Wheels

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

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

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