Vehicle Terrain Sensor

Vehicle and tire distances to objects

Vehicle Terrian Sensor will be removed in a future release. Use Simulation 3D Terrain Sensor instead. For more information, see Version History.

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Libraries:
Vehicle Dynamics Blockset / Vehicle Scenarios / Sim3D / Sim3D Vehicle / Components
Simulink 3D Animation / Simulation 3D / Sensors

Description

Note

Simulating models with the Vehicle Terrain Sensor block requires Simulink^® 3D Animation™.

The Vehicle Terrain Sensor block implements ray tracing to detect the terrain below the tires and objects in front of the vehicle. Specifically, for these actor components, the block returns the hit location (in the world coordinate system) and the distance to an object.

• Vehicle body

• Left front wheel

• Right front wheel

• Left rear wheel

• Right rear wheel

Tip

Verify that the Vehicle Terrain Sensor block executes before the Simulation 3D Fisheye Camera block. That way, the Unreal Engine^® 3D visualization environment prepares the data before the Vehicle Terrain Sensor block receives it. To check the block execution order, right-click the blocks and select Properties. On the General tab, confirm these Priority settings:

• Simulation 3D Scene Configuration — 0

• Vehicle Terrain Sensor — 1

For more information about execution order, see Control and Display Execution Order.

Actors are scene objects that support 3D translation, rotation, and scale. Parts are actor components. Components do not exist by themselves; they are associated with an actor.

Hit Distance

To calculate the hit distances shown in the illustration, the block implements these equations.

Front of vehicle to object, DistToHitVhAdjust	DistToHitVh = GetLength(CntrLocVh,HitLocVh) DistToHitVhAdjust = DistToHitVh - VehCntrLngthVal EndLocVh = CntrLocVh + VehRayLngth - VehRayOffset VehRayOffset = CntrLocVh - StartLocVh VehRayLngth = StartLocVh - EndLocVh
Tires to terrain, DistToHitTrAdjust	DistToHitTr = GetLength(CntrLocTr, HitLocTr) DistToHitTrAdjust = DistToHitTr - TireRadiiVal EndLocTr = CntrLocTr + LengthTr - OffsetTr OffsetTr = CntrLocTr - StartLocTr LengthTr = StartLocTr - EndLocTr

This illustration and equations use these variables.

CntrLocVh	Vehicle center location
DistToHitVh	Distance from vehicle center location to object
DistToHitVhAdjust	Distance from the front of the vehicle to object
EndLocVh	Vehicle ray trace end
HitLocVh	Vehicle hit location
OffsetVh	Vehicle trace offset
StartLocVh	Vehicle ray trace start
VehRayLngth	Vehicle trace length
VehCntrLngthVal	Distance from vehicle center to front
CntrLocTr	Tire center location
DistToHitTr	Distance from tire center location to terrain
DistToHitTrAdjust	Distance from tire to terrain
HitLocTr	Tire hit location
EndLocTr	Tire ray trace end
OffsetTr	Tire trace offset
StartLocTr	Tire ray trace start
LengthTr	Tire trace length
TireRadiiVal	Tire radius

Hit Event

To determine a hit event, the block uses the ray trace. The block provides the hit location in the world coordinate system.

Miss Event

To determine a miss event, the block uses the ray trace.

Examples

Scene Interrogation with Camera and Ray Tracing Reference Application

Interrogate a 3D Unreal Engine scene with a vehicle dynamics model by using a camera and ray tracing reference application project.

Open Script

Ports

Input

VehCntr — Vehicle distance from center to front

scalar

Distance from the vehicle center to front, VehCntrLngthVal, in m.

Dependencies

Distance to vehicle center	Creates Port	Creates Parameter
Constant	None	Distance from vehicle center to front, VehCntrLngthVal
External input	VehCntr	None

TireRadii — Tire radii

array

Tire radii, TireRadiiVal, in m.

Dependencies

Distance to tire center Setting	Creates Port	Creates Parameter
Constant	None	Distance from tire center to ground, TireRadiiVal
External input	TireRadii	None

Output

Info — Bus signal

bus

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

Signal	Description	Variable	Units
HitFlg	Vehicle and wheel hit flag: Hit an object – 1 Miss an object – 0	$$\left[\begin{array}{c}Vehicle\\ FrontLeft\\ FrontRight\\ RearLeft\\ RearRight\end{array}\right]$$	NA
HitLoc	Vehicle, HitLocVh, and tire, HitLocTr, hit locations, in world coordinate system X-, Y, and Z- axes, respectively	$$\left[\begin{array}{ccc}Vehicl{e}_X& Vehicl{e}_Y& Vehicl{e}_Z\\ FrontLef{t}_X& FrontLef{t}_Y& FrontLef{t}_Z\\ FrontRigh{t}_X& FrontRigh{t}_Y& FrontRigh{t}_Z\\ RearLef{t}_X& RearLef{t}_Y& RearLef{t}_Z\\ RearRea{r}_X& RearRea{r}_Y& RearRea{r}_Z\end{array}\right]$$	m
StartLoc	Vehicle, StartLocVh, and tire, StartLocTr, ray trace start locations, in world coordinate system X-, Y, and Z- axes, respectively		m

VehHitDist — Front of vehicle distance to object

scalar

Distance from the front of the vehicle to object, DistToHitVhAdjust, in m.

TireHitDist — Tire distance to terrain

vector

Distance from tire to terrain, DistToHitTrAdjust, in m.

DistToHitTrAdjust = $$[\begin{array}{cccc}FrontLeft& FrontRight& RearLef& RearRight]\end{array}$$

Parameters

Actor Setup

Tag for actor in 3D scene, ActorTag — Name

SimulinVehicle1 (default) | character vector

Actor name.

Actors are scene objects that support 3D translation, rotation, and scale. Parts are actor components. Components do not exist by themselves; they are associated with an actor.

The block does not support multiple instances of the same actor tag. To refer to the same scene actor when you use the 3D block pairs (e.g. Simulation 3D Actor Transform Get and Simulation 3D Actor Transform Set), specify the same Tag for actor in 3D scene, ActorTag parameter.

Distance to vehicle center — Selection

Constant (default) | External input

Configure how to provide the distance to the vehicle center.

Dependencies

Distance to vehicle center	Creates Port	Creates Parameter
Constant	None	Distance from vehicle center to front, VehCntrLngthVal
External input	VehCntr	None

Distance to tire center — Selection

Constant (default) | External input

Configure how to provide the distance to the tire center.

Dependencies

Distance to tire center Setting	Creates Port	Creates Parameter
Constant	None	Distance from tire center to ground, TireRadiiVal
External input	TireRadii	None

Distance from vehicle center to front, VehCntrLngthVal — Vehicle center

0 (default) | scalar

Distance from the vehicle center to front, VehCntrLngthVal, in m.

Dependencies

Distance to vehicle center	Creates Port	Creates Parameter
Constant	None	Distance from vehicle center to front, VehCntrLngthVal
External input	VehCntr	None

Distance from tire center to ground, TireRadiiVal — Tire radii

0 (default) | scalar

Tire radius, TireRadiiVal, in m.

Dependencies

Distance to tire center Setting	Creates Port	Creates Parameter
Constant	None	Distance from tire center to ground, TireRadiiVal
External input	TireRadii	None

Trace Lengths

Vehicle body x-axis trace length, VehRayLngth — Trace length

5 (default) | scalar

Vehicle body trace length, VehRayLngth, in m.

Left front wheel z-axis trace length, LfRayLngth — Trace length

5 (default) | scalar

Left front wheel trace length, LfRayLngth and LengthTr, in m.

Right front wheel z-axis trace length, RfRayLngth — Trace length

5 (default) | scalar

Right front wheel trace length, RfRayLngth and LengthTr, in m.

Left rear wheel z-axis trace length, LrRayLngth — Trace length

5 (default) | scalar

Left rear wheel trace length, LrRayLngth and LengthTr, in m.

Right rear wheel z-axis trace length, RrRayLngth — Trace length

5 (default) | scalar

Right rear wheel trace length, RrRayLngth and LengthTr, in m.

Starting Point Offsets

Vehicle body x-axis trace offset, VehRayOffset — Offset the vehicle ray trace

0 (default) | scalar

Vehicle body trace offset, OffsetVh, in m.

Left front wheel z-axis trace offset, LfRayOffset — Offset the left front wheel ray trace

0 (default) | scalar

Left front wheel trace offset, LfRayOffset and OffsetTr, in m.

Right front wheel z-axis trace offset, RfRayOffset — Offset the right front wheel ray trace

0 (default) | scalar

Right front wheel trace offset, RfRayOffset and OffsetTr, in m.

Left rear wheel z-axis trace offset, LrRayOffset — Offset the left rear wheel ray trace

0 (default) | scalar

Left rear wheel trace offset, LrRayOffset and OffsetTr, in m.

Right rear wheel z-axis trace offset, RrRayOffset — Offset the right rear wheel ray trace

0 (default) | scalar

Right rear wheel trace offset, RrRayOffset and OffsetTr, in m.

Enable Traces

Vehicle body — Enable vehicle body ray tracing

on (default) | off

Enable vehicle body ray tracing.

Left front tire — Enable left front tire ray tracing

on (default) | off

Enable left front tire ray tracing.

Right front tire — Enable right front tire ray tracing

on (default) | off

Enable right front tire ray tracing.

Left rear tire — Enable left rear tire ray tracing

on (default) | off

Enable left rear tire ray tracing.

Right rear tire — Enable right rear tire ray tracing

on (default) | off

Enable right rear tire ray tracing.

Trace line visualization — Visualize ray traces

on (default) | off

Enable trace line visualization.

Sample time — Sample time

-1 (default) | scalar

Sample time, T_s. The graphics frame rate is the inverse of the sample time.

Version History

Introduced in R2018a

R2024a: Requires Simulink 3D Animation

Simulating models with the Vehicle Terrain Sensor block requires Simulink 3D Animation.

R2024a: To be removed

The Vehicle Terrian Sensor block will be removed in a future release. Instead, use the Simulation 3D Terrain Sensor block to implement ray tracing to detect the terrain below vehicle tires.