Simulation 3D Ultrasonic Array

Ultrasonic sensor model with tunable acoustic parameters in 3D simulation environment

Since R2023a

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Libraries:
Automated Driving Toolbox / Simulation 3D
Simulink 3D Animation / Simulation 3D / Sensors

Description

Note

Simulating models with the Simulation 3D Ultrasonic Array block requires Simulink^® 3D Animation™.

The Simulation 3D Ultrasonic Array block generates detections from range measurements taken by an array of ultrasonic sensors with tunable acoustic parameters, mounted on an ego vehicle in a 3D simulation environment. This environment is rendered using the Unreal Engine^® from Epic Games^®. The block calculates range measurements based on the distance between the sensor and the closest point on the detected object. The block also provides parameters to control the waveform of the ultrasonic signal used by the sensor to calculate range measurements.

If you set Sample time to -1, the block uses the sample time specified in the Simulation 3D Scene Configuration block. To use this sensor, you must include a Simulation 3D Scene Configuration block in your model.

Tip

The Simulation 3D Scene Configuration block must execute before the Simulation 3D Ultrasonic Array block. That way, the Unreal Engine 3D visualization environment prepares the data before the Simulation 3D Ultrasonic Array 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 Ultrasonic Array — 1

For more information about execution order, see How Unreal Engine Simulation for Automated Driving Works.

Ports

Output

Detections — Object detections

Simulink bus containing MATLAB^® structure

Object detections, returned as a Simulink bus containing a MATLAB structure. For more details about buses, see Create Nonvirtual Buses (Simulink).

You can pass object detections from these sensors and other sensors to a tracker, such as a Multi-Object Tracker block, and generate tracks.

The structure must contain these fields.

Property	Description
Time	Measurement time
Measurement	Distance measurement to the closest object
MeasurementNoise	Measurement noise covariance matrix
SensorIndex	Unique ID of the sensor
ObjectClassID	Object classification
ObjectAttributes	Additional information passed to tracker
MeasurementParameters	Parameters used by initialization functions of nonlinear Kalman tracking filters

This table describes the additional information in the ObjectAttributes property.

ObjectAttributes

Attribute	Definition
TargetIndex	Identifier of the actor, ActorID, that generated the detection. For false alarms, this value is negative.
PointOnTarget	Coordinate of the point on the detected object that the sensor used to compute the distance measurement. It is in the vehicle coordinate system. Use this for visualizing detections in the Bird's-Eye Scope app.

For MeasurementParameters, the measurements are relative to the parent frame. The parent frame is the ego vehicle body.

MeasurementParameters

Parameter	Definition
Frame	Enumerated type indicating the frame used to report measurements. The Frame is always set to 'spherical' and the detections are reported in spherical coordinates for Ultrasonic Detection Generator.
OriginPosition	3-D vector offset of the sensor origin from the parent frame origin.
OriginVelocity	Velocity of the sensor coordinate system with respect to the parent frame.
IsParentToChild	Logical scalar indicating if Orientation performs a frame rotation from the parent coordinate frame to the child coordinate frame. When IsParentToChild is false, then Orientation performs a frame rotation from the child coordinate frame to the parent coordinate frame.
HasAzimuth	Indicates whether measurements contain azimuth components.
HasRange	Indicates whether measurements contain range components. Always true for Ultrasonic Detection Generator.
HasElevation	Indicates whether measurements contain elevation components. Always false for Ultrasonic Detection Generator.
HasVelocity	Indicates whether measurements contain velocity or range rate components. Always false for Ultrasonic Detection Generator.
FieldOfView	2-D vector containing the azimuth and elevation field of view values of the sensor.

Dependencies

To enable this output port, on the Parameters tab, check the Use bus output parameter.

Has object — Flag indicating whether any detectable object is present in the sensor field-of-view

true | false

Flag indicating whether any detectable object is present in the sensor field-of-view, returned as a logical scalar. An object is considered detectable if its closest distance to the sensor is greater than the minimum detection-only range specified in the Detection ranges (m) parameter.

Dependencies

To enable this output port, on the Parameters tab, clear the Use bus output parameter.

Has range — Flag indicating whether range measurement is possible for any object present in the sensor field-of-view

true | false

Flag indicating whether range measurement is possible for any object present in the sensor field-of-view, returned as a logical scalar. For any object in the field-of-view, range measurement is possible if its closest distance to the sensor is greater than the minimum-distance range specified in the Detection Ranges (m) parameter.

Dependencies

To enable this output port, on the Parameters tab, clear the Use bus output parameter.

Range — Distance measurement to the closest object

nonnegative scalar

Distance measurement to the closest object, returned as a nonnegative scalar.

Dependencies

To enable this output port, on the Parameters tab, clear the Use bus output parameter.

Translation — Sensor location

real-valued 1-by-3 vector

Sensor location along the X-axis, Y-axis, and Z-axis of the scene. The Translation values are in the world coordinates of the scene. In this coordinate system, the Z-axis points up from the ground. Units are in meters.

Dependencies

To enable this port, on the Ground Truth tab, select Output location (m) and orientation (rad).

Data Types: double

Rotation — Sensor orientation

real-valued 1-by-3 vector

Roll, pitch, and yaw sensor orientation about the X-axis, Y-axis, and Z-axis of the scene. The Rotation values are in the world coordinates of the scene. These values are positive in the clockwise direction when looking in the positive directions of these axes. Units are in radians.

Dependencies

To enable this port, on the Ground Truth tab, select Output location (m) and orientation (rad).

Data Types: double

Parameters

Mounting

Sensor identifier — Unique sensor identifier

1 (default) | positive integer

Specify the unique identifier of the sensor. In a multisensor system, the sensor identifier enables you to distinguish between sensors. When you add a new sensor block to your model, the Sensor identifier of that block is N + 1, where N is the highest Sensor identifier value among the existing sensor blocks in the model.

Example: 2

Parent name — Name of parent vehicle

Scene Origin (default) | vehicle name

Name of the parent to which the sensor is mounted, specified as Scene Origin or as the name of a vehicle in your model. The vehicle names that you can select correspond to the Name parameters of the simulation 3D vehicle blocks in your model. If you select Scene Origin, the block places a sensor at the scene origin.

Example: SimulinkVehicle1

Mounting location — Sensor mounting location

Origin (default) | Front bumper | Rear bumper | Right mirror | Left mirror | Rearview mirror | Hood center | Roof center | ...

Sensor mounting location.

• When Parent name is Scene Origin, the block mounts the sensor to the origin of the scene. You can set the Mounting location to Origin only. During simulation, the sensor remains stationary.

• When Parent name is the name of a vehicle, the block mounts the sensor to one of the predefined mounting locations described in the table. During simulation, the sensor travels with the vehicle.

Vehicle Mounting Location	Description	Orientation Relative to Vehicle Origin [Roll, Pitch, Yaw] (deg)
Origin	Forward-facing sensor mounted to the vehicle origin, which is on the ground and at the geometric center of the vehicle (see Coordinate Systems for Unreal Engine Simulation in Automated Driving Toolbox)	[0, 0, 0]
Front bumper Front center	Forward-facing sensor mounted to the front bumper	[0, 0, 0]
Rear bumper Rear center	Backward-facing sensor mounted to the rear bumper	[0, 0, 180]
Right mirror	Downward-facing sensor mounted to the right side-view mirror	[0, –90, 0]
Left mirror	Downward-facing sensor mounted to the left side-view mirror	[0, –90, 0]
Rearview mirror	Forward-facing sensor mounted to the rearview mirror, inside the vehicle	[0, 0, 0]
Hood center	Forward-facing sensor mounted to the center of the hood	[0, 0, 0]
Roof center	Forward-facing sensor mounted to the center of the roof	[0, 0, 0]

Roll, pitch, and yaw are clockwise-positive when looking in the positive direction of the X-axis, Y-axis, and Z-axis, respectively. When looking at a vehicle from above, the yaw angle (the orientation angle) is counterclockwise-positive because you are looking in the negative direction of the axis.

The X-Y-Z mounting location of the sensor relative to the vehicle depends on the vehicle type. To specify the vehicle type, use the Type parameter of the Simulation 3D Vehicle with Ground Following to which you mount the sensor. To obtain the X-Y-Z mounting locations for a vehicle type, see the reference page for that vehicle.

To determine the location of the sensor in world coordinates, open the sensor block. Then, on the Ground Truth tab, select the Output location (m) and orientation (rad) parameter and inspect the data from the Translation output port.

Specify offset — Specify offset from mounting location

off (default) | on

Select this parameter to specify an offset from the mounting location by using the Relative translation [X, Y, Z] (m) and Relative rotation [Roll, Pitch, Yaw] (deg) parameters.

Relative translation [X, Y, Z] (m) — Translation offset relative to mounting location

[0, 0, 0] (default) | real-valued 1-by-3 vector

Translation offset relative to the mounting location of the sensor, specified as a real-valued 1-by-3 vector of the form [X, Y, Z]. 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 vehicle coordinate system, where:

• The X-axis points forward from the vehicle.

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

• The Z-axis points up.

The origin is the mounting location specified in the Mounting location parameter. This origin is different from the vehicle origin, which is the geometric center of the vehicle.

If you mount the sensor to the scene origin by setting Parent name to Scene Origin, then X, Y, and Z are in the world coordinates of the scene.

For more details about the vehicle and world coordinate systems, see Coordinate Systems for Unreal Engine Simulation in Automated Driving Toolbox.

Example: [0,0,0.01]

Dependencies

To enable this parameter, select Specify offset.

Relative rotation [Roll, Pitch, Yaw] (deg) — Rotational offset relative to mounting location

[0, 0, 0] (default) | real-valued 1-by-3 vector

Rotational offset relative to the mounting location of the sensor, specified as a real-valued 1-by-3 vector of the form [Roll, Pitch, Yaw]. Roll, pitch, and yaw are the angles of rotation about the X-, Y-, and Z-axes, respectively. Units are in degrees.

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 vehicle coordinate system, where:

• The X-axis points forward from the vehicle.

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

• The Z-axis points up.

• Roll, pitch, and yaw are clockwise-positive when looking in the forward direction of the X-axis, Y-axis, and Z-axis, respectively. If you view a scene from a 2D top-down perspective, then the yaw angle (also called the orientation angle) is counterclockwise-positive because you are viewing the scene in the negative direction of the Z-axis.

The origin is the mounting location specified in the Mounting location parameter. This origin is different from the vehicle origin, which is the geometric center of the vehicle.

If you mount the sensor to the scene origin by setting Parent name to Scene Origin, then X, Y, and Z are in the world coordinates of the scene.

For more details about the vehicle and world coordinate systems, see Coordinate Systems for Unreal Engine Simulation in Automated Driving Toolbox.

Example: [0,0,10]

Dependencies

To enable this parameter, select Specify offset.

Sample time — Sample time

-1 (default) | positive scalar

Sample time of the block, in seconds, specified as a positive scalar. The 3D simulation environment frame rate is the inverse of the sample time.

If you set the sample time to -1, the block inherits its sample time from the Simulation 3D Scene Configuration block.

Sensor Parameters

Intrinsic parameters

Relative mounting locations (m) — Relative mounting locations of individual sensors in the ultrasonic array

[[0, -0.67, 0]; [0, -0.22, 0]; [0, 0.22, 0]; [0, 0.67, 0]] (default) | real-valued N-by-3 array

Relative mounting locations of individual sensors in the ultrasonic array, specified as a real-valued N-by-3 array. N is the number of sensors in the ultrasonic array and the locations are relative to the sensor mounting position specified by the Mounting Location parameter. Each row of the array must be a 1-by-3 vector of the form [X, Y, Z]. Units are in meters.

Relative mounting rotations (deg) — Relative mounting rotations of individual sensors in the ultrasonic array

zeros(4,3) (default) | real-valued N-by-3 array

Relative mounting rotations of individual sensors in the ultrasonic array, specified as a real-valued N-by-3 array. N is the number of sensors in the ultrasonic array and the rotations are relative to the sensor mounting orientation specified by the Mounting Location parameter. Each row of the array must be a 1-by-3 vector of the form [roll, pitch, yaw]. Units are in degrees.

Horizontal Field of view (deg) — Horizontal field of view of ultrasonic array

70 (default) | positive real scalar

Horizontal field of view of ultrasonic array, specified as a positive real scalar. This field of view defines the total angular extent spanned by all sensors of the ultrasonic array in the horizontal direction relative to their orientations. You must specify the horizontal field of view horizontalFOV in the range (0, 360]. Units are in degrees.

Vertical field of view (deg) — Vertical field of view of ultrasonic array

35 (default) | positive real scalar

Vertical field of view of ultrasonic array, specified as a positive real scalar. This field of view defines the total angular extent spanned by all sensors of the ultrasonic array in the vertical direction relative to their orientations. You must specify the vertical field of view in the range (0, 180]. Units are in degrees.

Detection ranges (m) — Detection range vector of ultrasonic array (m)

[0.03 0.15 5.5] (default) | 1-by-3 nonnegative real-valued vector of form [minDetOnlyRange minDistRange maxDistRange]

Detection range vector of the ultrasonic array, specified as a 1-by-3 nonnegative real-valued vector of the form [minDetOnlyRange minDistRange maxDistRange], where minDetOnlyRange < minDistRange < maxDistRange. Units are in meters. These values determine the detections and distance values returned by the ultrasonic array.

• When the detected object is at a distance between minDistRange and maxDistRange, the sensor returns a positive distance value.

• When the detected object is at a distance between minDetOnlyRange and minDistRange, the sensor detects the object, but cannot determine the distance and returns a value of 0.

• When the object is at a distance below minDetOnlyRange or above maxDistRange, the sensor returns an empty cell array.

Signal parameters

Acoustic frequency (kHz) — Frequency of sound waves used by all sensor emitters in ultrasonic array

50 (default) | positive real scalar

Frequency of sound waves used by all sensor emitters in the ultrasonic array, specified as a positive real scalar. Units are in kHz.

Sampling frequency (kHz) — Sampling frequency of all sensor receivers in ultrasonic array

500 (default) | positive real scalar

Sampling frequency of all sensor receivers in the ultrasonic array, specified as a positive real scalar. To sample a signal of a given frequency, the sampling frequency of the receiver must be at least two times that frequency. Units are in kHz.

Pulse width (s) — Pulse width of ultrasonic waves used by all sensors in ultrasonic array

1e-6 (default) | positive real scalar

Pulse width of the ultrasonic waves used by all sensors in the ultrasonic array, specified as a positive real scalar.

Gain — Vector gain for sound signal used by sensors in ultrasonic array

[1, 0] (default) | real-valued scalar | real-valued 1-by-2 vector

Vector gain for the sound signal used by the sensors in ultrasonic array, real-valued scalar or a 1-by-2 vector of the form [a, b]. The blocks multiplies the scalar gain as a constant, and the vector gain as a time signal of the form a + b*t with the ultrasonic signal.

Sound speed (m/s) — Speed of sound in environment

330 (default) | positive real scalar

Speed of sound in the environment, specified as a positive real scalar. Units are in m/s.

Use bus output — Select to output signals together as bus signal

on (default) | off

Select to output detections as a bus signal using the Detections port. Clear Use bus output to instead enable the Has object, Has range, and Range output ports.

Ground Truth

Output location (m) and orientation (rad) — Output location and orientation of sensor

off (default) | on

Select this parameter to output the translation and rotation of the sensor at the Translation and Rotation ports, respectively.

Version History

Introduced in R2023a

R2024a: Requires Simulink 3D Animation

Simulating models with the Simulation 3D Ultrasonic Array block requires Simulink 3D Animation.

R2024a: Ground truth parameter

On the Ground Truth tab, select Output location (m) and orientation (rad) to output the translation and rotation of the sensor at the Translation and Rotation ports, respectively.