# VehicleComponents

## AEB

The Autonomous Emergency Braking system checks if a collision is likely to occur in the near future and, if necessary, brakes to avoid the collision. In each timestep, the system evaluates all objects detected by a Sensor and calculates the time to collision (TTC) for this object based on the perceived movement of the object. If, for any object, the TTC is lower than the threshold of the component, then the component gets activated. The system deactivates if the TTC is larger than 1,5 times the threshold of the component.

Attribute | Type | Unit | Description
--- | --- | --- | ---
CollisionDetectionLongitudinalBoundary | Double | m | Additional length added the vehicle boundary when checking for collision detection
CollisionDetectionLateralBoundary | Double | m | Additional width added the vehicle boundary when checking for collision detection
TTC | Double | s | Time to collision which is used to trigger AEB
Acceleration | Double | m/s² | Braking acceleration when activated

    <ProfileGroup Type="AEB">
        <Profile Type="AEB" Name="AEB1">
            <Double Key="CollisionDetectionLongitudinalBoundary" Value="4.0"/>
            <Double Key="CollisionDetectionLateralBoundary" Value="1.5"/>
            <Double Key="TTC" Value="2.0"/>
            <Double Key="Acceleration" Value="-2"/>
        </Profile>
        ...
    </ProfileGroup>

## DynamicsTrajectoryFollower

This module forces agents to drive according to a specific trajectory. The trajectory is defined in the scenario. This module is disabled by default and is activated if a trajectory from openSCENARIO is triggered. It is always important that the trajectories matches the current scenery file, otherwise the Agent could be placed outside of valid lanes. If the agent gets placed on a invalid position, it will be deleted.

All attributes are required.

Attribute | Type | Description
--- | --- | ---
AutomaticDeactivation | Bool | If true, the trajectory follower relinquishes control of the vehicle after the final instruction in the TrajectoryFile.
EnforceTrajectory | Bool | If true, the trajectory follower overrides external input related to the vehicle’s travel.

    <ProfileGroup Type="DynamicsTrajectoryFollower">
        <Profile Name="BasicTrajectoryFollower">
            <Bool Key="AutomaticDeactivation" Value="true"/>
            <Bool Key="EnforceTrajectory" Value="true"/>
        </Profile>
    </ProfileGroup>

## FMU Wrapper

The FMU Wrapper provides a connection to arbitrary FMUs (Functional Mock-up Unit). An FMU has to be compatible with the FMI 1.0 or the FMI 2.0 specification (Functional Mock-up Interface) and has to be ABI (Application Binary Interface) compatible with the opSimulation binary.

Additional reading about FMI is provided by the FMI standard website at https://fmi-standard.org/. For interfacing the FMUs in openPASS, the Modelon FMI Library is used, which is recommended on the FMI standard website. See https://jmodelica.org/.

FMU package format

FMI defines a packaging format for FMUs. The used container format is ZIP. It basically contains - among other parts - the compiled FMU code (as `*.dll` or `*.so`, depending on the platform) and the `modelDescription.xml`. Latter provides meta-data about the FMU, i. e. - Author information - Model name, identifier and description - Generation timestamp - Name and datatype of model variables (inputs and outputs)

Architectural overview

The wrapper is instantiated as a component of an agent. It reads the input variables for the FMU from the simulation and provides it the FMU and reads the output of the FMU and forwards it via signals to other agent components.

Framework channels

The wrapper can use input and output signals via Channels as every other agent component does. Framework channels (signals) can provide data and can also be written to by the wrapper. In addition, the wrapper is able to access the c AgentInterface and c WorldInterface methods.

FMI variables

Communication with the FMU happens via FMI variables (inputs and outputs). The wrapper will read in available variables from `modelDescription.xml` in the FMU package. These variables need to be mapped to variables and signals of OpenPASS in the VehicleComponentProfile.

FMI 1.0 supports these standard datatypes: - bool - integer - real - string

Configuration

Configuration of a particular FMU takes place in `ProfilesCatalog.xml`. An example of a static system configuration can be found here “sim/contrib/examples/Configurations/StaticOSMPSensorDataToTrafficUpdateStepper”.

The following parameters are always required for the FmuWrapper. Depending on the FmuHandler additional parameters may be needed.

Key | Type | Default | Description
--- | --- | --- | ---
FmuPath | string | - | Path to FMU file, either absolute or relative to the simulator’s configuration directory.
Logging | bool | true | If set to true, FMU initialization and execution task are logged to a text file.
CsvOutput | bool | true | If set to true, FMI outputs are logged to a CSV file.
UnzipOncePerInstance | bool | true | If set to true, unpack the FMU once for each running instance, instead of once per FMU file (forced to `true` on Linux systems)
FmuType | string | - | Type of the FMU (“OSMP” supported)

    <ProfileGroup Type="FMU1">
      <Profile Name="FMU">
        <String Key="FmuPath" Value="OSMPSensorDataToTrafficUpdateStepper.fmu"/>
        <String Key="FmuType" Value="OSMP"/>
        <Bool Key="Logging" Value="true"/>
        <Bool Key="CsvOutput" Value="false"/>
        <Bool Key="UnzipOncePerInstance" Value="false"/>
        <String Key="Input_OSMPSensorDataIn" Value="SensorData"/>
        <String Key="Output_OSMPTrafficUpdateOut" Value="TrafficUpdate"/>
     <Bool Key="WriteJson_SensorData" Value="false"/>
     <Bool Key="WriteJson_TrafficUpdate" Value="false"/>
      </Profile>
    </ProfileGroup>

Upon instantiation of the FMU wrapper, it will extract the FMU ZIP file to a temporary directory. Then the `modelDescription.xml` is parsed and the FMU is checked for compatibility.

If the parameter `CsvOutput` is set to true, a subfolder “FmuWrapper/Agent<ID>” will be created in the simulator’s “results” directory. “<ID>” is replaced with the agent id. FMI output data will be logged to a file inside this directory. The filename consists of the FMU’s name and extension “csv”. This output can then be used for visualization in a spreadsheet application or it may be processed in any other way.

Same goes for parameter `Logging` (having “log” as output file extension).

If `UnzipOncePerInstance` is set to true, the FMU will be unzipped multiple times into different temporary directories.

OSMP FMU

OSMP allows to pass input to the FMU as OSI messages as well as receive output as OSI message. For more information on OSMP see https://github.com/OpenSimulationInterface/osi-sensor-model-packaging.

The OsmpFmuHandler has the following additional (optional) parameters:

Key | Type | Description
--- | --- | ---
Init_var_name | string | var_name references an FMU variable (as defined in FMU’s modelDescription.xml) to which a specific OSI message is sent during initialization Allowed values: GroundTruth
Input_var_name | string | var_name references an FMU variable (as defined in FMU’s modelDescription.xml) to which a specific OSI message is sent Allowed values: SensorView, SensorViewConfig, SensorData, TrafficCommand
Output_var_name | string | var_name references an FMU variable (as defined in FMU’s modelDescription.xml) from which a specific OSI message is received Allowed values: SensorViewConfigRequest, SensorData, TrafficUpdate, `MotionCommand`
Parameter_var_name | any | The value of the parameter is assigned to the FMU variable var_name
Parameter_transformation[mapping ]_name | string/string/any* | Same as Parameter_name but with an preceding transformation according to a mapping. Currently, only mappings between the same types are supported. *;When using TransformList as transformation, the type of the data is expected to be a string and the string must be a comma separated list of values. Allowed values: transformation: Transform, TransformList mapping: ScenarioName>Id Example: Parameter_TransformList[ScenarioName>Id]_*name*
WriteSensorViewOutput | bool | If true the SensorView is written into a JSON file
WriteTrafficCommandOutput | bool | If true the TrafficCommand is written into a JSON file
WriteGroundTruthOutput | bool | If true the GroundTruth is written into a JSON file
WriteSensorDataOutput | bool | If true the SensorData is written into a JSON file
WriteTrafficUpdateOutput | bool | If true the TrafficUpdate is written into a JSON file
EnforceDoubleBuffering | bool | If true the wrapper will throw an error if FMU doesn’t use double buffering. Defaults to false.

The type of OSI messages the OsmpFmuHandler sends and receives is defined by its parameters. Only messages for which an FMU variable is given in the configuration are sent/received. An additional parameter defines whether the message should be logged as JSON file for every agent and every timestep (see table above).

Currently these messages are supported:

- SensorView: SensorView generated from the GroundTruth with this agent is host vehicle.

- SensorViewConfig, SensorViewConfigRequest: Configuration of a sensor according to OSMP.

- TrafficCommand: Trajectory from openSCENARIO, that will be converted into a TrafficCommand.

- SensorData: Output of a sensor. Can be input and/or output of an FMU. Received SensorData is forwarded to other components as SensorDataSignal.

- TrafficUpdate: Will be converted to a DynamicsSignal.

- MotionCommand: Will be converted to a DynamicsSignal. Has priority over TrafficUpdate.

Generic Handler

The Generic Fmu Handler allows to link Simulink models or any other FMU to openPASS. It lets the user link any input variables of the FMU to values of the Agent in the simulation and any output values of the FMU to signals, that are forwarded to other components. These mappings are defined with the following additional parameters, where the key describes the meaning in the simulation and the value is the variable in the modelDescription.xml:

Key | Type | Description
--- | --- | ---
Parameter_varName | any | Mapping of a fixed value (bool, integer, double, string) to an FMU input. `varName` references the FMU input defined in the modelDescription.xml.
Input_varName | string | Mapping of a specific value of the simulation to an FMU input. `varName` references the FMU input defined in the modelDescription.xml. The value of this parameter has to be one of the types specified in the table below.
Output_varName | string | Mapping of a FMU output to a specific field in a specific signal. `varName` references the FMU output defined in the modelDescription.xml. The value of this parameter has to be one of the types specified in the signal table below.

The allowed inputs (simulation values) are as follows:

Type | FMU Variable Type | Calculation
--- | --- | ---
VelocityEgo | Real | Absolute velocity (length of the velocity vector) at reference point
AccelerationEgo | Real | Longitudinal acceleration at reference point
CentripetalAccelerationEgo | Real | Centripetal acceleration at reference point
SteeringWheelEgo | Real | Angle of the steering wheel (in radian)
AccelerationPedalPositionEgo | Real | Position of the acceleration pedal in the interval [0, 1]
BrakePedalPositionEgo | Real | Position of the brake pedal in the interval [0, 1]
DistanceRefToFrontEdgeEgo | Real | Distance between the reference point and the front of the agent (static)
PositionXEgo | Real | X position of the reference point
PositionYEgo | Real | Y position of the reference point
YawEgo | Real | Yaw of the reference point
LaneEgo | Integer | Lane id of the MainLocatePoint on the route (0, if off route)
PositionSEgo | Real | S position of the reference point on the route (0, if off route)
PositionTEgo | Real | T position of the reference point on the route (0, if off route)
ExistenceFront | Boolean | true, if there is a object in front on the own lane (any range), false otherwise
PositionXFront | Real | X position of front object reference point (0, if no front object)
PositionYFront | Real | Y position of front object reference point (0, if no front object)
YawFront | Real | Yaw of front object reference point (0, if no front object)
PositionSFront | Real | S position of front object reference point on ego route (0, if no front object)
PositionTFront | Real | T position of front object reference point on ego route (0, if no front object)
RelativeDistanceFront | Real | Net distance to front object along route (0, if no front object)
WidthFront | Real | Width of front object (0, if no front object)
LengthFront | Real | Length of front object (0, if no front object)
DistanceRefToFrontEdgeFront | Real | Distance between the reference point and the front of the front object (0, if no front object)
VelocityFront | Real | Absolute velocity of front object at reference point (0, if no front object)
LaneFront | Integer | Lane id of the reference point of the front object on the ego route (0, if no front object)
ExistenceFrontFront | Boolean | true, if there are at least two objects in front on the own lane (any range), false otherwise
PositionXFrontFront | Real | X position of second front object reference point (0, if no second front object)
PositionYFrontFront | Real | Y position of second front object reference point (0, if no second front object)
RelativeDistanceFrontFront | Real | Net distance to second front object reference point (0, if no second front object)
VelocityFrontFront | Real | Absolute velocity of second front object reference point (0, if no second front object)
LaneFrontFront | Integer | Lane id of the reference point of second front object reference point (0, if no second front object)
LaneCountLeft | Integer | Number of lanes to the left of MainLocatePoint of type Driving, Exit, Entry, OnRamp or OffRamp
LaneCountRight | Integer | Number of lanes to the right of MainLocatePoint of type Driving, Exit, Entry, OnRamp or OffRamp
SpeedLimit_X | Real | Speed limit in effect in distance X meters from MainLocatePoint (999, if no speed limit)
RoadCurvature_X | Real | Road curvature in distance X meters from MainLocatePoint

If the FmuWrapper is linked to at least one sensor with InputId “Camera”, the following additional inputs are available. The objects seen by this sensor(s) are sorted by distance from the agent and accessed by indices starting from 0. For each object the values listed in the following table are available where X is the index of the object (between 0 and 9). If there are less objects than X, a default value is set (-1 for the Id, 0 for the other values).

Type | FMU Variable Type | Calculation
--- | --- | ---
SensorFusionObjectId_X | Integer | Id of the object
SensorFusionNumberOfDetectingSensors_X | Integer | Number of sensors detecting the object
SensorFusionRelativeS_X | Real | Distance between reference points along route (NaN, if object not on route)
SensorFusionRelativeNetS_X | Real | Net distance along route (NaN, if object not on route)
SensorFusionRelativeT_X | Real | Lateral obstruction for MainLocatePoint (NaN, if object not on route) (see GetObstruction)
SensorFusionRelativeNetLeft_X | Real | Lateral obstruction for leftmost point (NaN, if object not on route)
SensorFusionRelativeNetRight_X | Real | Lateral obstruction for rightmost point (NaN, if object not on route)
SensorFusionRelativeNetX_X | Real | Net distance between bounding boxes in x
SensorFusionRelativeNetY_X | Real | Net distance between bounding boxes in y
SensorFusionLane_X | Integer | Lane of MainLocatePoint
SensorFusionVelocity_X | Real | Absolute velocity at reference point
SensorFusionVelocityX_X | Real | Velocity in x at reference point
SensorFusionVelocityY_X | Real | Velocity in y at reference point
SensorFusionYaw_X | Real | Yaw

The FMU wrapper can output one or more of these signals: AccelerationSignal, LongitudinalSignal, SteeringSignal and DynamicsSignal

The name of the signal field has to be specified after the signal name. This means the output type is one of the following:

Type | FMU Variable Type
--- | ---
ComponentState | Enum
AccelerationSignal_Acceleration | Real
LongitudinalSignal_AccPedalPos | Real
LongitudinalSignal_BrakePedalPos | Real
LongitudinalSignal_Gear | Int
SteeringSignal_SteeringWheelAngle | Real
DynamicsSignal_Acceleration | Real
DynamicsSignal_Velocity | Real
DynamicsSignal_PositionX | Real
DynamicsSignal_PositionY | Real
DynamicsSignal_Yaw | Real
DynamicsSignal_YawRate | Real
DynamicsSignal_YawAcceleration | Real
DynamicsSignal_SteeringWheelAngle | Real
DynamicsSignal_CentripetalAcceleration | Real
DynamicsSignal_TravelDistance | Real

If one of these fields of a signal (except ComponentState) is mapped to an FMU variable, all fields of this signal have to be mapped. If the ComponentState is mapped to a FMU variable, it is used for all signals, otherwise it defaults to Acting.

## SensorGeometric2D

This sensor is selected, when a sensor is parameterized as ProfileGroup “Geometric2D”.

Parameter | Type | Unit | Description
--- | --- | --- | ---
DetectionRange | Double | m | Detection range
EnableVisualObstruction | Bool |  | Activates 2D sensor obstruction calculation
FailureProbability | Double |  | Probability object is not detected although it is visible
Latency | Double | s | Sensor latency
OpeningAngleH | Double | rad | Horizontal opening angle
RequiredPercentageOfVisibleArea | Double |  | Required percentage of an object within the sensor cone to trigger a detection

    <ProfileGroup Type="Geometric2D">
      <Profile Name="Standard">
        <Double Key="DetectionRange" Value="300"/>
        <Bool Key="EnableVisualObstruction" Value="false"/>
        <Double Key="FailureProbability" Value="0"/>
        <NormalDistribution Key="Latency" Max="0.0" Mean="0.0" Min="0.0" SD="0.0"/>
        <Double Key="OpeningAngleH" Value="0.35"/>
        <Double Key="RequiredPercentageOfVisibleArea" Value="0.001"/>
      </Profile>
    </ProfileGroup>

Note

Sensors also need a mounting position, defined w.r.t. the coordinate system of the vehicle (center of rear axis). See also VehicleProfiles.