Simulation 3D Terrain Sensor

Implement multipoint terrain sensor in 3D environment

Since R2022a

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Libraries:
Vehicle Dynamics Blockset / Vehicle Scenarios / Sim3D / Sim3D Vehicle / Components

Description

Note

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

The Simulation 3D Terrain Sensor block implements a multipoint terrain sensor in Unreal Engine^®. Use the block for contact modeling at high vehicle velocities over terrain changes, including speed bumps. The block implements ray tracing to detect the terrain below the tires. Use the block parameters to:

• Sense the terrain under any simulation 3D vehicle actor in the scene, including actors created by the Simulation 3D Vehicle and Simulation 3D Motorcycle blocks.

• Configure the ray origins, directions, and lengths to adjust the terrain sensor pattern for your scene and test scenario.

The block creates a terrain sensor pattern for each of the wheels on the vehicle actor. For specific patterns, this table provides the corresponding parameter settings.

Pattern	Parameter Settings
Five rays per wheel Rays originate at point specified by wheel spin axis Rays extend downward at 15° intervals Rays length is 6 m	Ray origins – zeros(5,3) Ray directions – [sqrt(3)/2 0 -1/2;1/2 0 -sqrt(3)/2; 0 0 -1; -1/2 0 -sqrt(3)/2; -sqrt(3)/2 0 -1/2] Ray lengths – ones(5,1)*6 Number of wheels on parent vehicle – 4
Five rays per wheel Rays originate at point specified by .37 m wheel radius Rays extend downward at 15° intervals Rays length is 4 m	Ray origins – zeros(5,3)+[0 0 -.37] Ray directions – [sqrt(3)/2 0 -1/2;1/2 0 -sqrt(3)/2; 0 0 -1; -1/2 0 -sqrt(3)/2; -sqrt(3)/2 0 -1/2] Ray lengths – ones(5,1)*4 Number of wheels on parent vehicle – 4
Nine rays per wheel Rays originate from points specified by .37 m wheel radius, along Y-axis of Z-up vehicle coordinate system Rays extend downward, along Z-axis of Z-up vehicle coordinate system Rays length is 2 m	Ray origins – [[0.2:-0.05:-0.2];zeros(1,9);zeros(1,9)]'+[0 0 -.37] Ray directions – zeros(9,3)+[0 0 -1] Ray lengths – ones(9,1)*2 Number of wheels on parent vehicle – 4

Tip

Verify that the Simulation 3D Scene Configuration block executes before the Simulation 3D Terrain Sensor block. That way, the Unreal Engine 3D visualization environment prepares the data before the Simulation 3D 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

• Simulation 3D Terrain Sensor — 1

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

Examples

Constant Radius Reference Application

Simulate a full vehicle dynamics model undergoing a constant radius maneuver. Use for vehicle dynamics ride and handling analysis and chassis controls development, including the dynamic steering response.

• Open Script

Longitudinal Motorcycle Braking Test Reference Application

Simulate an in-plane motorcycle model undergoing a braking test. Use for motorcycle dynamics ride and handling analysis and chassis controls development.

• Open Script

Ports

Output

Info — Bus signal

bus

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

Signal	Description	Units
WheelWPositions	Wheel W ray hit location relative to ray origin, specified as a real-valued N-by-3 array of the form [X, Y, Z] in the 3D visualization engine world coordinate system. N is the number of rays per wheel.	m
WheelWStatus	Wheel W ray hit status, specified as a N-by-1 array. N is the number of rays per wheel. Hit an object – 1 Miss an object – 0	NA

Parameters

Mounting

Sensor identifier, sensorId — Unique sensor identifier

0 (default) | positive integer

Unique sensor identifier, specified as a positive integer. In a multisensor system, the sensor identifier distinguishes between sensors. When you add a new sensor block to your model, the Sensor identifier of that block is N + 1. N is the highest Sensor identifier value among existing sensor blocks in the model.

Example: 2

Parent name, VehTag — Name of parent to which sensor is mounted

SimulinkVehicle1 (default) | vehicle name

Name of the parent to which the sensor is mounted, specified as the name of a vehicle in your model. The vehicle names that you can select from the drop-down list correspond to the Name parameters of the simulation 3D vehicle blocks in your model.

Example: SimulinkVehicle2

Parameters

Ray origins, RayOrigins — Ray origin

[0 0 1] (default) | real-valued N-by-3 array

Ray origin relative to the wheel spin axis, specified as a real-valued N-by-3 array of the form [X, Y, Z]. N is the number of rays. Units are in meters.

If you mount the sensor to a vehicle by setting Parent name to the name of that vehicle, then X, Y, and Z are in the 3D visualization engine coordinate system, where:

• The X-axis points forward from the vehicle.

• The Y-axis points to the right of the vehicle, as viewed when looking in the forward direction of the vehicle.

• The Z-axis points up.

Example: zeros(10,3)

Ray directions, RayDirections — Normalized ray direction

[0 0 -1] (default) | real-valued N-by-3 array

Normalized ray direction relative to wheel, specified as a real-valued N-by-3 array of the form [X, Y, Z]. N is the number of rays. Units are in dimensionless.

If you mount the sensor to a vehicle by setting Parent name to the name of that vehicle, then X, Y, and Z are in the 3D visualization engine coordinate system, where:

• The X-axis points forward from the vehicle.

• The Y-axis points to the right of the vehicle, as viewed when looking in the forward direction of the vehicle.

• The Z-axis points up.

Example: ones(10,3)

Ray lengths, RayLengths — Length

20 (default) | real-valued N-by-1 vector

Ray length, specified as a real-valued N-by-1 vector N, N is the number of rays. Units are in meters.

Example: ones(10,1)*10

Number of wheels on parent vehicle — Number of wheels

4 (default) | positive integer

Number of wheels on the parent vehicle to which the sensor is mounted. The vehicle name corresponds to the Name parameters of the simulation 3D vehicle blocks in your model.

Example: 6

Visualize trace line — Visualize ray traces

off (default) | on

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 R2022a

R2024a: Requires Simulink 3D Animation

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

R2023b: Support for multi-axle vehicles and motorcycles

The Simulation 3D Terrain Sensor block supports use with the simulation 3D motorcycle, tractor, and trailer blocks.

R2023b: Parameter name change

The Parent name, VehicleIdentifier parameter is renamed to Parent name, VehTag.