Bicycle Model
Implement a single track 3DOF rigid vehicle body to calculate longitudinal, lateral, and yaw motion
Libraries:
Automated Driving Toolbox /
Driving Scenario and Sensor Modeling
Vehicle Dynamics Blockset /
Vehicle Body
Description
Note
Simulating models with the Bicycle Model block requires Simulink® 3D Animation™.
The Bicycle Model block implements a rigid two-axle single track vehicle body model to calculate longitudinal, lateral, and yaw motion. The block accounts for body mass, aerodynamic drag, and weight distribution between the axles due to acceleration and steering. There are two types of Bicycle Model blocks.
Block | Implementation |
---|---|
Bicycle Model - Velocity Input |
|
Bicycle Model - Force Input |
|
To calculate the normal forces on the front and rear axles, the block uses rigid-body vehicle motion, suspension system forces, and wind and drag forces. The block resolves the force and moment components on the rigid vehicle body frame.
Ports
Input
WhlAngF — Wheel angle
scalar
Front wheel angle, in rad.
FxF — Force Input: Total longitudinal force on the front axle
scalar
Longitudinal force on the front axle,
FxF, along
vehicle-fixed x
-axis, in N.
Bicycle Model - Force Input block input port.
FxR — Force Input: Total longitudinal force on the rear axle
scalar
Longitudinal force on the rear axle,
FxR, along
vehicle-fixed x
-axis, in N.
Bicycle Model - Force Input block input port.
xdotin — Velocity Input: Longitudinal velocity
scalar
Vehicle CG velocity along vehicle-fixed x-axis, in m/s.
Bicycle Model - Velocity Input block input port.
Output
Info — Bus signal
bus
Bus signal containing these block values.
Signal | Description | Value | Units | |||||
---|---|---|---|---|---|---|---|---|
InertFrm | Cg | Disp | X | Vehicle CG displacement along the earth-fixed X-axis | Computed | m | ||
Y | Vehicle CG displacement along the earth-fixed Y-axis | Computed | m | |||||
Z | Vehicle CG displacement along the earth-fixed Z-axis | 0 | m | |||||
Vel | Xdot | Vehicle CG velocity along the earth-fixed X-axis | Computed | m/s | ||||
Ydot | Vehicle CG velocity along the earth-fixed Y-axis | Computed | m/s | |||||
Zdot | Vehicle CG velocity along the earth-fixed Z-axis | 0 | m/s | |||||
Ang | phi | Rotation of the vehicle-fixed frame about the earth-fixed X-axis (roll) | 0 | rad | ||||
theta | Rotation of the vehicle-fixed frame about the earth-fixed Y-axis (pitch) | 0 | rad | |||||
psi | Rotation of the vehicle-fixed frame about the earth-fixed Z-axis (yaw) | Computed | rad | |||||
FrntAxl | Disp | X | Front wheel displacement along the earth-fixed X-axis | Computed | m | |||
Y | Front wheel displacement along the earth-fixed Y-axis | Computed | m | |||||
Z | Front wheel displacement along the earth-fixed Z-axis | 0 | m | |||||
Vel | Xdot | Front wheel velocity along the earth-fixed X-axis | Computed | m/s | ||||
Ydot | Front wheel velocity along the earth-fixed Y-axis | Computed | m/s | |||||
Zdot | Front wheel velocity along the earth-fixed Z-axis | 0 | m/s | |||||
RearAxl | Disp | X | Rear wheel displacement along the earth-fixed X-axis | Computed | m | |||
Y | Rear wheel displacement along the earth-fixed Y-axis | Computed | m | |||||
Z | Rear wheel displacement along the earth-fixed Z-axis | 0 | m | |||||
Vel | Xdot | Rear wheel velocity along the earth-fixed X-axis | Computed | m/s | ||||
Ydot | Rear wheel velocity along the earth-fixed Y-axis | Computed | m/s | |||||
Zdot | Rear wheel velocity along the earth-fixed Z-axis | 0 | m/s | |||||
Hitch | Disp | X | Hitch offset from axle plane along the earth-fixed X-axis | Computed | m | |||
Y | Hitch offset from center plane along the earth-fixed Y-axis | Computed | m | |||||
Z | Hitch offset from axle plane along the earth-fixed Z-axis | Computed | m | |||||
Vel | Xdot | Hitch offset velocity from axle plane along the earth-fixed X-axis | Computed | m | ||||
Ydot | Hitch offset velocity from center plane along the earth-fixed Y-axis | Computed | m | |||||
Zdot | Hitch offset velocity from axle plane along the earth-fixed Z-axis | Computed | m | |||||
Geom | Disp | X | Vehicle chassis offset from axle plane along the earth-fixed X-axis | Computed | m | |||
Y | Vehicle chassis offset from center plane along the earth-fixed Y-axis | Computed | m | |||||
Z | Vehicle chassis offset from axle plane along the earth-fixed Z-axis | Computed | m | |||||
Vel | Xdot | Vehicle chassis offset velocity along the earth-fixed X-axis | Computed | m/s | ||||
Ydot | Vehicle chassis offset velocity along the earth-fixed Y-axis | Computed | m/s | |||||
Zdot | Vehicle chassis offset velocity along the earth-fixed Z-axis | Computed | m/s | |||||
BdyFrm | Cg | Vel | xdot | Vehicle CG velocity along the vehicle-fixed x-axis | Computed | m/s | ||
ydot | Vehicle CG velocity along the vehicle-fixed y-axis | Computed | m/s | |||||
zdot | Vehicle CG velocity along the vehicle-fixed z-axis | 0 | m/s | |||||
Ang | Beta | Body slip angle, β
| Computed | rad | ||||
AngVel | p | Vehicle angular velocity about the vehicle-fixed x-axis (roll rate) | 0 | rad/s | ||||
q | Vehicle angular velocity about the vehicle-fixed y-axis (pitch rate) | 0 | rad/s | |||||
r | Vehicle angular velocity about the vehicle-fixed z-axis (yaw rate) | Computed | rad/s | |||||
Acc | ax | Vehicle CG acceleration along the vehicle-fixed x-axis | Computed | gn | ||||
ay | Vehicle CG acceleration along the vehicle-fixed y-axis | Computed | gn | |||||
az | Vehicle CG acceleration along the vehicle-fixed z-axis | 0 | gn | |||||
xddot | Vehicle CG acceleration along the vehicle-fixed x-axis | Computed | m/s^2 | |||||
yddot | Vehicle CG acceleration along the vehicle-fixed y-axis | Computed | m/s^2 | |||||
zddot | Vehicle CG acceleration along the vehicle-fixed z-axis | 0 | m/s^2 | |||||
AngAcc | pdot | Vehicle angular acceleration about the vehicle-fixed x-axis | 0 | rad/s | ||||
qdot | Vehicle angular acceleration about the vehicle-fixed y-axis | 0 | rad/s | |||||
rdot | Vehicle angular acceleration about the vehicle-fixed z-axis | Computed | rad/s | |||||
DCM | Direction cosine matrix | Computed | rad | |||||
Forces | Body | Fx | Net force on vehicle CG along the vehicle-fixed x-axis | Computed | N | |||
Fy | Net force on vehicle CG along the vehicle-fixed y-axis | Computed | N | |||||
Fz | Net force on vehicle CG along the vehicle-fixed z-axis | 0 | N | |||||
Ext | Fx | External force on vehicle CG along the vehicle-fixed x-axis | Computed | N | ||||
Fy | External force on vehicle CG along the vehicle-fixed y-axis | Computed | N | |||||
Fz | External force on vehicle CG along the vehicle-fixed z-axis | 0 | N | |||||
Hitch | Fx | Hitch force applied to body at the hitch location along the vehicle-fixed x-axis | Input | N | ||||
Fy | Hitch force applied to body at the hitch location along the vehicle-fixed y-axis | Input | N | |||||
Fz | Hitch force applied to body at the hitch location along the vehicle-fixed z-axis | Input | N | |||||
FrntAxl | Fx | Longitudinal force on front wheel, along the vehicle-fixed x-axis | Computed | N | ||||
Fy | Lateral force on front wheel along the vehicle-fixed y-axis | Computed | N | |||||
Fz | Normal force on front wheel, along the vehicle-fixed z-axis | Computed | N | |||||
RearAxl | Fx | Longitudinal force on rear wheel, along the vehicle-fixed x-axis | Computed | N | ||||
Fy | Lateral force on rear wheel along the vehicle-fixed y-axis | Computed | N | |||||
Fz | Normal force on rear wheel, along the vehicle-fixed z-axis | Computed | N | |||||
Tires | FrntTire | Fx | Front tire force, along the vehicle-fixed x-axis | Computed | N | |||
Fy | Front tire force, along the vehicle-fixed y-axis | Computed | N | |||||
Fz | Front tire force, along the vehicle-fixed z-axis | Computed | N | |||||
RearTire | Fx Fx | Rear tire force, along the vehicle-fixed x-axis | Computed | N | ||||
Fy | Rear tire force, along the vehicle-fixed y-axis | Computed | N | |||||
Fz | Rear tire force, along the vehicle-fixed z-axis | Computed | N | |||||
Drag | Fx | Drag force on vehicle CG along the vehicle-fixed x-axis | Computed | N | ||||
Fy | Drag force on vehicle CG along the vehicle-fixed y-axis | Computed | N | |||||
Fz | Drag force on vehicle CG along the vehicle-fixed z-axis | Computed | N | |||||
Grvty | Fx | Gravity force on vehicle CG along the vehicle-fixed x-axis | Computed | N | ||||
Fy | Gravity force on vehicle CG along the vehicle-fixed y-axis | Computed | N | |||||
Fz | Gravity force on vehicle CG along the vehicle-fixed z-axis | Computed | N | |||||
Moments | Body | Mx | Body moment on vehicle CG about the vehicle-fixed x-axis | 0 | N·m | |||
My | Body moment on vehicle CG about the vehicle-fixed y-axis | Computed | N·m | |||||
Mz | Body moment on vehicle CG about the vehicle-fixed z-axis | 0 | N·m | |||||
Drag | Mx | Drag moment on vehicle CG about the vehicle-fixed x-axis | 0 | N·m | ||||
My | Drag moment on vehicle CG about the vehicle-fixed y-axis | Computed | N·m | |||||
Mz | Drag moment on vehicle CG about the vehicle-fixed z-axis | 0 | N·m | |||||
Ext | Mx | External moment on vehicle CG about the vehicle-fixed x-axis | 0 | N·m | ||||
My | External moment on vehicle CG about the vehicle-fixed y-axis | Computed | N·m | |||||
Mz | External moment on vehicle CG about the vehicle-fixed z-axis | 0 | N·m | |||||
Hitch | Mx | Hitch moment at the hitch location about vehicle-fixed x-axis | 0 | N·m | ||||
My | Hitch moment at the hitch location about vehicle-fixed y-axis | Computed | N·m | |||||
Mz | Hitch moment at the hitch location about vehicle-fixed z-axis | 0 | N·m | |||||
FrntAxl | Disp | x | Front wheel displacement along the vehicle-fixed x-axis | Computed | m | |||
y | Front wheel displacement along the vehicle-fixed y-axis | Computed | m | |||||
z | Front wheel displacement along the vehicle-fixed z-axis | Computed | m | |||||
Vel | xdot | Front wheel velocity along the vehicle-fixed x-axis | Computed | m/s | ||||
ydot | Front wheel velocity along the vehicle-fixed y-axis | Computed | m/s | |||||
zdot | Front wheel velocity along the vehicle-fixed z-axis | 0 | m/s | |||||
Steer | WhlAngFL | Front left wheel steering angle | Computed | rad | ||||
WhlAngFR | Front right wheel steering angle | Computed | rad | |||||
RearAxl | Disp | x | Rear wheel displacement along the vehicle-fixed x-axis | Computed | m | |||
y | Rear wheel displacement along the vehicle-fixed y-axis | Computed | m | |||||
z | Rear wheel displacement along the vehicle-fixed z-axis | Computed | m | |||||
Vel | xdot | Rear wheel velocity along the vehicle-fixed x-axis | Computed | m/s | ||||
ydot | Rear wheel velocity along the vehicle-fixed y-axis | Computed | m/s | |||||
zdot | Rear wheel velocity along the vehicle-fixed z-axis | 0 | m/s | |||||
Steer | WhlAngRL | Rear left wheel steering angle | Computed | rad | ||||
WhlAngRR | Rear right wheel steering angle | Computed | rad | |||||
Hitch | Disp | x | Hitch offset from axle plane along the vehicle-fixed x-axis | Input | m | |||
y | Hitch offset from center plane along the vehicle-fixed y-axis | Input | m | |||||
z | Hitch offset from axle plane along the earth-fixed z-axis | Input | m | |||||
Vel | xdot | Hitch offset velocity along the vehicle-fixed x-axis | Computed | m/s | ||||
ydot | Hitch offset velocity along the vehicle-fixed y-axis | Computed | m/s | |||||
zdot | Hitch offset velocity along the vehicle-fixed z-axis | Computed | m/s | |||||
Pwr | Ext | Applied external power | Computed | W | ||||
Hitch | Power loss due to hitch | Computed | W | |||||
Drag | Power loss due to drag | Computed | W | |||||
Geom | Disp | x | Vehicle chassis offset from axle plane along the vehicle-fixed x-axis | Input | m | |||
y | Vehicle chassis offset from center plane along the vehicle-fixed y-axis | Input | m | |||||
z | Vehicle chassis offset from axle plane along the earth-fixed z-axis | Input | m | |||||
Vel | xdot | Vehicle chassis offset velocity along the vehicle-fixed x-axis | Computed | m/s | ||||
ydot | Vehicle chassis offset velocity along the vehicle-fixed y-axis | Computed | m/s | |||||
zdot | Vehicle chassis offset velocity along the vehicle-fixed z-axis | 0 | m/s | |||||
Ang | Beta | Body slip angle, β
| Computed | rad |
Signal | Description | Value | Units | |||
---|---|---|---|---|---|---|
PwrInfo | PwrTrnsfrd | PwrFxExt | Externally applied longitudinal force power | Computed | W | |
PwrFyExt | Externally applied lateral force power | Computed | W | |||
PwrMzExt | Externally applied roll moment power | Computed | W | |||
PwrFwFx | Longitudinal force applied at the front axle power | Computed | W | |||
PwrFwFy | Lateral force applied at the front axle power | Computed | W | |||
PwrFwRx | Longitudinal force applied at the rear axle power | Computed | W | |||
PwrFwRy | Lateral force applied at the rear axle power | Computed | W | |||
PwrNotTrnsfrd | PwrFxDrag | Longitudinal drag force power | Computed | W | ||
PwrFyDrag | Lateral drag force power | Computed | W | |||
PwrMzDrag | Drag pitch moment power | Computed | W | |||
PwrStored | PwrStoredGrvty | Rate change in gravitational potential energy | Computed | W | ||
PwrStoredxdot | Rate of change of longitudinal kinetic energy | Computed | W | |||
PwrStoredydot | Rate of change of lateral kinetic energy | Computed | W | |||
PwrStoredr | Rate of change of rotational yaw kinetic energy | Computed | W |
xdot — Vehicle body longitudinal velocity
scalar
Vehicle CG velocity along vehicle-fixed x
-axis, in
m/s.
ydot — Vehicle body lateral velocity
scalar
Vehicle CG velocity along vehicle-fixed y
-axis, in
m/s.
psi — Yaw
scalar
Rotation of the vehicle-fixed frame about earth-fixed
Z
-axis (yaw), in rad..
r — Yaw rate
scalar
Vehicle angular velocity, r
, about the
vehicle-fixed z
-axis (yaw rate), in rad/s.
Parameters
Number of wheels on front axle, NF — Front wheel count
2
(default) | scalar
Number of wheels on front axle, NF. The value is dimensionless.
Number of wheels on rear axle, NR — Rear wheel count
2
(default) | scalar
Number of wheels on rear axle, NR. The value is dimensionless.
Vehicle mass, m — Vehicle mass
2000
(default) | scalar
Vehicle mass, m, in kg.
Longitudinal distance from center of mass to front axle, a — Front axle distance
1.4
(default) | scalar
Horizontal distance a from the vehicle CG to the front wheel axle, in m.
Longitudinal distance from center of mass to rear axle, b — Rear axle distance
1.6
(default) | scalar
Horizontal distance b from the vehicle CG to the rear wheel axle, in m.
Vertical distance from center of mass to axle plane, h — Height
0.35
(default) | scalar
Height of vehicle CG above the axles, h, in m.
Initial inertial frame longitudinal position, X_o — Position
0
(default) | scalar
Initial vehicle CG displacement along earth-fixed X-axis, in m.
Initial longitudinal velocity, xdot_o — Velocity
0
(default) | scalar
Initial vehicle CG velocity along vehicle-fixed x-axis, in m/s.
Front tire corner stiffness, Cy_f — Stiffness
12e3
(default) | scalar
Front tire corner stiffness, Cyf, in N/rad.
Rear tire corner stiffness, Cy_r — Stiffness
11e3
(default) | scalar
Rear tire corner stiffness, Cyr, in N/rad.
Initial inertial frame lateral displacement, Y_o — Position
0
(default) | scalar
Initial vehicle CG displacement along earth-fixed Y-axis, in m.
Initial lateral velocity, ydot_o — Velocity
0
(default) | scalar
Initial vehicle CG velocity along vehicle-fixed y-axis, in m/s.
Yaw polar inertia, Izz — Inertia
4000
(default) | scalar
Yaw polar inertia, in kg*m^2.
Initial yaw angle, psi_o — Psi rotation
0
(default) | scalar
Rotation of the vehicle-fixed frame about earth-fixed Z-axis (yaw), in rad.
Initial yaw rate, r_o — Yaw rate
0
(default) | scalar
Vehicle angular velocity about the vehicle-fixed z-axis (yaw rate), in rad/s.
Longitudinal drag area, Af — Effective vehicle cross-sectional area
2
(default) | scalar
Effective vehicle cross-sectional area, Af, to calculate the aerodynamic drag force on the vehicle, in m2.
Longitudinal drag coefficient, Cd — Air drag coefficient
.3
(default) | scalar
Air drag coefficient, Cd. The value is dimensionless.
Longitudinal lift coefficient, Cl — Air lift coefficient
.1
(default) | scalar
Air lift coefficient, Cl. The value is dimensionless.
Longitudinal drag pitch moment, Cpm — Pitch drag
.1
(default) | scalar
Longitudinal drag pitch moment coefficient, Cpm. The value is dimensionless.
Relative wind angle vector, beta_w — Wind angle
[0:0.01:0.3]
(default) | vector
Relative wind angle vector, βw, in rad.
Side force coefficient vector, Cs — Side force coefficient
[0:0.03:0.9]
(default) | vector
Side force coefficient vector coefficient, Cs. The value is dimensionless.
Yaw moment coefficient vector, Cym — Yaw moment drag
[0:0.01:0.3]
(default) | vector
Yaw moment coefficient vector, Cym. The value is dimensionless.
Absolute pressure, Pabs — Pressure
101325
(default) | scalar
| scalar
Environmental absolute pressure, Pabs, in Pa.
Air temperature, Tair — Temperature
273
(default) | scalar
Environmental absolute temperature, T, in K.
Gravitational acceleration, g — Gravity
9.81
(default) | scalar
Gravitational acceleration, g, in m/s^2.
Nominal friction scaling factor, mu — Friction scale factor
1
(default) | scalar
Nominal friction scale factor, μ. The value is dimensionless.
Longitudinal velocity tolerance, xdot_tol — Tolerance
.01
(default) | scalar
Longitudinal velocity tolerance, in m/s.
Nominal normal force, Fznom — Normal force
5000
(default) | scalar
Nominal normal force, in N.
Geometric longitudinal offset from axle plane, longOff — Longitudinal offset
0
(default) | scalar
Vehicle chassis offset from axle plane along body-fixed x-axis, in m. When you use the 3D visualization engine, consider using the offset to locate the chassis independent of the vehicle CG.
Geometric lateral offset from center plane, latOff — Lateral offset
0
(default) | scalar
Vehicle chassis offset from center plane along body-fixed y-axis, in m. When you use the 3D visualization engine, consider using the offset to locate the chassis independent of the vehicle CG.
Geometric vertical offset from axle plane, vertOff — Vertical offset
0
(default) | scalar
Vehicle chassis offset from axle plane along body-fixed z-axis, in m. When you use the 3D visualization engine, consider using the offset to locate the chassis independent of the vehicle CG.
References
[1] Gillespie, Thomas. Fundamentals of Vehicle Dynamics. Warrendale, PA: Society of Automotive Engineers (SAE), 1992.
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
Version History
Introduced in R2018aR2024a: Requires Simulink 3D Animation
Simulating models with the Bicycle Model block requires Simulink 3D Animation.
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