..
  *******************************************************************************
  Copyright (c) 2021 in-tech GmbH
                2022-2023 Bayerische Motoren Werke Aktiengesellschaft (BMW AG)
                2023 Volkswagen AG

  This program and the accompanying materials are made available under the
  terms of the Eclipse Public License 2.0 which is available at
  http://www.eclipse.org/legal/epl-2.0.

  SPDX-License-Identifier: EPL-2.0
  *******************************************************************************

.. _components_vehiclecomponents:

VehicleComponents
-----------------

.. _components_aeb:

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.

.. table::
   :class: tight-table

   ====================================== ====== ==== ===================================================================================
   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
   ====================================== ====== ==== ===================================================================================

.. code-block:: xml

   <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>

.. _components_trajectoryfollower:

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.

.. table::
   :class: tight-table

   ===================== ==== =======================================================================================================================
   Attribute             Type Description
   ===================== ==== =======================================================================================================================
   AutomaticDeactivation Bool If true, the trajectory follower relinquishes control of the vehicle after the final instruction in the TrajectoryFile.
                              If false, it stops at the last point of the trajectory.
   EnforceTrajectory     Bool If true, the trajectory follower overrides external input related to the vehicle's travel.
   ===================== ==== =======================================================================================================================

.. code-block:: xml

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

.. _components_fmuwrapper:

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.

.. image:: _static/images/FmuWrapperOverview.svg
      :alt: |op| FMU wrapper architectural overview

**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

By using OSMP, three integer values can be used to support full osi messages

**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.

.. table::
   :class: tight-table
   :name: FmuWrapper basic configuration

   ==================== ======= ======= ================================================================================================================================
   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.
   ==================== ======= ======= ================================================================================================================================

.. literalinclude:: /../../../repo/sim/contrib/examples/Configurations/DynamicOSMPSensorDataToTUStepper/ProfilesCatalog.xml
   :language: xml
   :dedent: 2
   :start-at: <ProfileGroup Type="FMU1">
   :end-at: </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).

**Primitive Datatypes**

The FMU Wrapper allows to link Simulink models or any other FMU to |op|.
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 |op| components.
These mappings are defined with the following optional parameters.

.. note::

   Be careful with the size of integer data types when used in Matlab/Simulink. The FMU integer data type shall always be 32 bit or bigger, e.g. for IDs.

.. table::
   :class: tight-table

   ===================================== ======= ==================================================================================================================
   Key                                   Type    Description
   ===================================== ======= ==================================================================================================================
   Parameter\_\ *varName*                any     Mapping of a fixed value (bool, integer, double, string) to an FMU input:

                                                 * ``varName`` references an FMI input variable.
                                                 * The type of the parameter has to match the FMI variable type.

   Parameter_AssignSpecial\_\ *varName*  any     Mapping of a specific value of the simulation to an FMU input, assigned only once at FMU initialization:

                                                 * ``varName`` references an FMI input variable.
                                                 * The parameter is always of type string.
                                                 * The value of this parameter has to be one of the types specified in the `Special simulation values`_ table below,
                                                   which will also determine the required type of the FMI variable.

   Input\_\ *varName*                    string  Mapping of a specific value of the simulation to an FMU input:

                                                 * ``varName`` references an FMI input variable.
                                                 * The value of this parameter has to be one of the types specified in the `Input simulation values`_ table below.

   Output\_\ *varName*                   string  Mapping of a FMU output to a specific field in a specific signal:

                                                 * ``varName`` references an FMI output variable.
                                                 * The value of this parameter has to be one of the types specified in the `Output simulation signals`_ table below.
   ===================================== ======= ==================================================================================================================

The allowed special simulation values are as follows:

.. table::
   :class: tight-table
   :name: Special simulation values

   ========================================= ================== ==================================================================================================
   Type                                      FMU Variable Type  Calculation
   ========================================= ================== ==================================================================================================
   RandomSeed                                Integer            The random seed of the current simulation run.
   OutputPath                                String             An output path unique to this FmuWrapper instance.
                                                                The path will always refer to a directory below the simulator's current result folder.
                                                                This directory is not necessarily created by the FmuWrapper, depending on the setting of
                                                                `CsvOutput` and `Logging` parameters (see `FmuWrapper basic configuration`_).
   MaxSteering                               Real               The `max_steering` property of an agent's front axle as defined in OpenSCENARIO (catalog).
   SteeringRatio                             Real               The steering ratio of the vehicle model.
                                                                Has to be defined in the properties of the Entity in the OpenSCENARIO catalog with the name
                                                                ``SteeringRatio`` and the value has to be a valid floating point expression.
   NumberOfGears                             Integer            The number of gears of the vehicle model.
                                                                Has to be defined in the properties of the Entity in the OpenSCENARIO catalog with the name
                                                                ``NumberOfGears`` and the value has to be a valid integer.
   GearRatio\ *N*                            Real               The ratio of the Nth gear.
                                                                Has to be defined in the properties of the Entity in the OpenSCENARIO catalog with the name
                                                                ``GearRatioN`` and the value has to be a valid floating point expression.
                                                                *N* is allowed to be in the range 1-9.
   ========================================= ================== ==================================================================================================

The allowed inputs (simulation values) are as follows:

.. table::
   :class: tight-table
   :name: Input simulation values

   ========================================= ================== ==================================================================================================
   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 front center 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 front center of type Driving, Exit, Entry, OnRamp or OffRamp
   LaneCountRight                            Integer            Number of lanes to the right of front center of type Driving, Exit, Entry, OnRamp or OffRamp
   SpeedLimit\_\ *X*                         Real               Speed limit in effect in distance *X* meters from front center (999, if no speed limit)
   RoadCurvature\_\ *X*                      Real               Road curvature in distance *X* meters from front center
   ========================================= ================== ==================================================================================================

* **reference point**: Center of the rear axle
* **front center**: Center of the front of the bounding box of the object

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).
Only the list of objects is taken from the sensor.
The values are then calculated by the FmuWrapper (not from the SensorData).

.. table::
   :class: tight-table

   ============================================ ================== ========================================================================================================
   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 front center (NaN, if object not on route) (see :ref:`world_getobstruction`)
   SensorFusionRelativeX\_\ *X*                 Real               Relative distance between reference points in x in world coordinates
   SensorFusionRelativeY\_\ *X*                 Real               Relative distance between reference points in y in world coordinates
   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 in world coordinates
   SensorFusionRelativeNetY\_\ *X*              Real               Net distance between bounding boxes in y in world coordinates
   SensorFusionLane\_\ *X*                      Integer            Lane of front center
   SensorFusionVelocity\_\ *X*                  Real               Absolute velocity at reference point
   SensorFusionVelocityX\_\ *X*                 Real               Velocity in x at reference point in world coordinates
   SensorFusionVelocityY\_\ *X*                 Real               Velocity in y at reference point in world coordinates
   SensorFusionYaw\_\ *X*                       Real               Yaw in world coordinates
   ============================================ ================== ========================================================================================================

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:

.. table::
   :class: tight-table
   :name: Output simulation signals

   ====================================== =================== =========================================
   Type                                   FMU Variable Type   Enum Values
   ====================================== =================== =========================================
   ComponentState                         Enum                Undefined, Disabled, Armed, Acting
   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
   CompCtrlSignal_MovementDomain          Enum                Undefined, Lateral, Longitudinal, Both
   CompCtrlSignal_WarningActivity         Bool
   CompCtrlSignal_WarningLevel            Enum                INFO, WARNING
   CompCtrlSignal_WarningType             Enum                OPTIC, ACOUSTIC, HAPTIC
   CompCtrlSignal_WarningIntensity        Enum                LOW, MEDIUM, HIGH
   CompCtrlSignal_WarningDirection        Enum
   ====================================== =================== =========================================

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.

**OSI Data**

OSMP (OsiSensorModelPackaging) is a package layer specification for the Open Simulation Interface (OSI).
It 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 FmuHandler has the following additional (optional) parameters:

.. table::
   :class: tight-table

   ========================================================= ==================== ===============================================================================================================================================
   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`
   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*. |br| Currently, only mappings between the same types are supported. |br| \*;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. |br|  |br| Allowed values: |br| *transformation*: `Transform`, `TransformList` |br| *mapping*: `ScenarioName>Id` |br|  |br| Example: `Parameter_TransformList[ScenarioName>Id]\_\ *name*`
   WriteJson\_\ *var_name*                                   bool                 If true the osi message specified by *var_name* is written to a json file
   WriteTrace\_\ *var_name*                                  bool                 If true the osi message specified by *var_name* is written to the trace 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 FmuHandler 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.
* GroundTruth: Will be used as groundtruth information for everything that exists in the simulation world.

**FmuVariables**

FmuVariables can have different variability and causality.

* There are the following causalities: Input, Output, Parameter and CalculatedParameter
* Input or outputs can have the variability constant, fixed, discrete or continuous
* Parameter or CalculatedParameter can have the variability constant, fixed or tunable

In openPASS we have the initialization phase, which is only called once. In that phase first readValues is called.
Then parameter values are synchronized between different config files. The following priority is used for the synchronization:

modelDescription < systemConfig

Afterwards still in the initialization phase writeValues is called.
During the whole simulation in openPASS all the trigger functions are called each time step.
For the FMU component we call WriteValues before trigger and readValues afterwards.
For the first two time steps we have the following calls for read- and writeValues:

    1) ReadValues (Init)
    2) WriteValues (Init)
    3) WriteValues
    4) Trigger
    5) ReadValues
    6) WriteValues
    7) Trigger
    8) ReadValues

Depending on them, FmuVariables are written/read to/from the FMU on different occasions, which is shown in the following table.


.. list-table:: Write- and ReadValues depending on variability and causality
   :widths: 5 5 5 5 5
   :header-rows: 1
   :stub-columns: 1

   * -
     - ReadValues - Init
     - WriteValues - Init
     - WriteValues - Trigger
     - ReadValues - Trigger
   * - Input - fixed
     - x
     - x
     -
     -
   * - Input - discrete or continuous
     - x
     - x
     - x
     -
   * - Output - fixed
     - x
     -
     -
     -
   * - Output - discrete or continuous
     - x
     -
     -
     - x
   * - Parameter - fixed
     - x
     - x
     -
     -
   * - Parameter - tunable
     - x
     - x
     - x
     -
   * - CalculatedParameter - fixed
     - x
     -
     -
     -
   * - CalculatedParameter - tunable
     - x
     -
     -
     - x

.. note::
   For alle kinds of Input, Output, Parameter and CalculatedParameter there exists the variablity "constant".
   All constant values are only read into openPASS once at the initialization phase.
   Never will these values be written onto the FMU.

.. _components_geometric2d:

SensorGeometric2D
~~~~~~~~~~~~~~~~~

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

.. table::
   :class: tight-table

   =============================== ====== ==== ==================================================================================================
   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    Delay the sensor output
   DetectionDelayTime              Double s    Time an object needs to be in detection range before it is detected (optional)
   MaxDropOutTime                  Double s    Time after which delay for undetected object starts anew (optional)
   OpeningAngleH                   Double rad  Horizontal opening angle
   RequiredPercentageOfVisibleArea Double      Required percentage of an object within the sensor cone to trigger a detection
   =============================== ====== ==== ==================================================================================================

.. literalinclude:: /../../../repo/sim/contrib/examples/Configurations/ADAS_AEB_PreventingCollisionWithObstacle/ProfilesCatalog.xml
   :language: xml
   :dedent: 2
   :start-at: <ProfileGroup Type="Geometric2D">
   :end-at: </ProfileGroup>

.. note:: 
   
   Sensors also need a mounting position, defined w.r.t. the coordinate system of the vehicle (center of rear axis).
   See also :ref:`profilescatalog_vehicleprofiles`.

ReceiverCar2X
~~~~~~~~~~~~~

This type is selected, when a sensor is parameterized as ProfileGroup "ReceiverCar2X".

.. table::
   :class: tight-table

   ================== ====== ==== ===========================================================================================
   Parameter          Type   Unit Description
   ================== ====== ==== ===========================================================================================
   FailureProbability Double      Probability object is not detected although it is visible
   Latency            Double s    Sensor latency
   Sensitivity        Double W/m² Sensitivity of the sensor
   ================== ====== ==== ===========================================================================================

.. literalinclude:: /../../../repo/sim/contrib/examples/Configurations/ADAS_Car2X/ProfilesCatalog.xml
   :language: xml
   :dedent: 2
   :start-at: <ProfileGroup Type="ReceiverCar2X">
   :end-at: </ProfileGroup>

The moving object is detected if the received SignalStrength is greater than the Sensitivity of the ReceiverCar2X .

The received SignalStrength is calculated by :math:`ss_{\text{received}} = \frac {ss_{\text{sender}}} {4 \cdot pi \cdot d \cdot d}`, where the symbols meanings are:

============================ ===================================================
Symbol                       Description                                     
============================ ===================================================
:math:`ss_{\text{received}}` Received strength of the signal [1/m²] 
:math:`ss_{\text{sender}}`   Sent strength of the signal [1/m²]    
:math:`d`                    Distance between the receiver agent and sender [m]                         
============================ ===================================================

.. note:: 
   
   Sensors also need a mounting position, defined w.r.t. the coordinate system of the vehicle (center of rear axis).
   See also :ref:`profilescatalog_vehicleprofiles`.

.. |br| raw:: html

      <br>

VehicleDynamics
~~~~~~~~~~~~~~~

Components of this group can be used to model the vehicle dynamics. The vehicle dynamics model has a modular design. If necessary, the individual components can be replaced by the user with their own models. The vehicle dynamics model consists of six components listed below:


.. table::
   :class: tight-table

   ================================  ==================================================================================================================================================================
   Component                         Short Description
   ================================  ==================================================================================================================================================================
   :ref:`components_steeringsystem`  The steering model transfers the driver's input into the vehicle's wheel angle
   :ref:`components_powertrain`      The powertrain model converts the accelerator pedal position into wheel drive torques, under consideration of the selected gear
   :ref:`components_brakesystem`     The brake model converts the brake pedal position into wheel brake torques 
   :ref:`components_tiremodel`       The tire model converts the predetermined drive and braking torques of the tires into tire longitudinal and lateral forces, under consideration of the wheel angles
   :ref:`components_motionmodel`     The motion model calculates the translational and rotational vehicle movement with the calculated tire forces
   :ref:`components_chassismodel`    The chassis model determines the dynamic wheel loads via the vehicle's longitudinal and lateral acceleration
   ================================  ==================================================================================================================================================================


The following figure gives an overview of the driving dynamics components and their signals:


.. image:: _static/images/VehicleDynamicsOverview.svg
      :alt: |op| Vehicle dynamics overview



.. _components_steeringsystem:

ActionSteeringSystem
^^^^^^^^^^^^^^^^^^^^

The steering model obtains the "SteeringRatio" property from the :ref:`scenario_vehiclemodels` and uses it to calculate the steering angle of the front wheels. 
Both wheels are turned at the same angle. Steering elasticities are currently not taken into account. The following parameter can be used to set a static toe:

.. table::
   :class: tight-table

   ========= ============ ==== =========================================================================================================================
   Attribute Type         Unit Description
   ========= ============ ==== =========================================================================================================================
   StaticToe VectorDouble rad  Static toe of the wheels (A positive value corresponds to a toe-in; wheels are indexed from the front left in the vector)
   ========= ============ ==== =========================================================================================================================

.. _components_powertrain:

ActionPowertrain
^^^^^^^^^^^^^^^^

The powertrain model contains an engine model and a gear model. The type of the powertrain can be set using the following parameters:

.. table::
   :class: tight-table

   ============== ====== ==== =============================================================================================================================
   Attribute      Type   Unit Description
   ============== ====== ==== =============================================================================================================================
   TypeDrivetrain String -    Type of drivetrain; A selection can be made between front-wheel drive (FWD), rear-wheel drive (RWD) and all-wheel drive (AWD)
   FrontRatioAWD  Double -    Distribution of the drive torque to the front axle in the case of all-wheel drive (AWD); Range 0-1
   ============== ====== ==== =============================================================================================================================

The wheel speed is converted into an engine speed [Hz] according to the axle ratio and the transmission ratio of the selected gear.
The axle ratio and gear ratios are obtained from the :ref:`scenario_vehiclemodels` ("AxleRatio" & "GearRatio"). The average value of the powered wheels is used for the determination of the engine speed.

.. math::
   \omega_{engine} = \omega_{wheels,avg} \cdot  i_{axle} \cdot i_{gear,selected}

The maximum possible engine torque [Nm] is limited by the engine power [W] or the maximum engine torque [Nm].
The engine power and the maximum engine torque are obtained from the :ref:`scenario_vehiclemodels` ("MaximumEnginePower" & "MaximumEngineTorque").

.. math::
   M_{engine,max,current} = \begin{cases}
    \frac{P_{engine,max}}{\omega_{engine}}     & \text{ if } \frac{P_{engine,max}}{\omega_{engine}} < M_{engine,max} \\
    M_{engine,max}  & \text{ if } \frac{P_{engine,max}}{\omega_{engine}} >= M_{engine,max}
	\end{cases}

When 98% of the maximum speed of the motor is reached ("MaximumEngineSpeed" in the :ref:`scenario_vehiclemodels`), the engine torque is linearly reduced to 0.

The maximum engine torque is scaled via the accelerator pedal position (input). This value is calculated back to the total wheel drive torque via the gear ratio.

.. math::
   M_{wheels,current} = M_{engine,max,current} \cdot  position_{accelerator pedal} \cdot  i_{axle} \cdot  i_{gear,selected}

The wheel total drive torque is evenly distributed to the wheels of an axle according to the definition of the drive type.
With all-wheel drive, the entire wheel drive torque is distributed statically over the defined ratio.


.. _components_brakesystem:

ActionBrakeSystem
^^^^^^^^^^^^^^^^^

The brake model is a linearized model. The brake pedal position is used as input. As output, the model returns the braking torques of the wheels as a vector.
The model considers a response time [ms] and linear factors [m/s³] for the increase and decrease of the braking force.The distribution of braking force between the front and rear axles can be defined statically.

.. table::
   :class: tight-table

   ============================ ====== ==== ==============================================================================================================
   Attribute                    Type   Unit Description
   ============================ ====== ==== ==============================================================================================================
   FrontAxlePercentage          Double   -  Distribution of the brake torque to the front axle in the case of all-wheel drive (AWD); Range 0-1
   BrakeDecelerationInclineRate Double m/s³ Linear Rate of braking force increase  
   BrakeDecelerationDeclineRate Double m/s³ Linear Rate of braking force decrease
   BrakeResponseTimeMs          Double ms   Brake response time
   ============================ ====== ==== ==============================================================================================================


The maximum braking force of the system is determined from the maximum possible deceleration and the mass of the vehicle and is scaled by the brake pedal position (Input). 
The maximum possible deceleration and the vehicle mass are obtained from the :ref:`scenario_vehiclemodels` ("maxDeceleration" & "mass").

.. math::
   F_{brake,max} = a_{deceleration,max} \cdot m_{vehicle} \cdot  position_{brake pedal}

When the brake is applied, a deceleration is calculated after the response time has elapsed. Then the braking force is built up linearly until the maximum or requested braking force has been reached.

.. math::
   F_{brake,current} = rate_{incline} \cdot (t_{brake} -  t_{response})

When the brake is released, the braking force is dissipated with the decline rate until it has dropped to zero. After that, the response time builds up again.
The braking force is divided among the axles according to the parameter "FrontAxlePercentage". Another input allows you to request a prefill that reduces the response time without braking


.. _components_chassismodel:

DynamicsChassis
^^^^^^^^^^^^^^^

The chassis model determines the vertical forces of the four wheels from the longitudinal and lateral acceleration of the vehicle. Constant spring and damper rates are taken into account, which can be defined by the following parameters per axis:

.. table::
   :class: tight-table

   ============================ ============ ==== ==============================================================================================================
   Attribute                    Type         Unit Description
   ============================ ============ ==== ==============================================================================================================
   SpringCoefficient            VectorDouble N/m  Constant spring coefficient for each axis
   DamperCoefficient            VectorDouble Ns/m Constant damper coefficient for each axis 
   ============================ ============ ==== ==============================================================================================================

.. _components_tiremodel:

DynamicsTireModel
^^^^^^^^^^^^^^^^^

The tire model is freely configurable and includes a degressive behaviour. The tire forces are modeled according to Rill using the TMEasy model. The following parameters can be set for the tire model per axis :

.. table::
   :class: tight-table

   ==================== ============ ==== ==============================================================================================================
   Attribute            Type         Unit Description
   ==================== ============ ==== ==============================================================================================================
   MuTireMaxXFRef       VectorDouble -    Normalized scaling factor for maximum longitudinal force at reference vertical force
   MuTireMaxX2FRef      VectorDouble -    Normalized scaling factor for maximum longitudinal force at double reference vertical force  
   MuTireSlideXFRef     VectorDouble -    Normalized scaling factor for sliding longitudinal force at reference vertical force                         
   MuTireSlideX2FRef    VectorDouble -    Normalized scaling factor for sliding longitudinal force at double reference vertical force                               
   SlipTireMaxXFRef     VectorDouble -    Longitudinal slip at maximum longitudinal force at reference vertical force
   SlipTireMaxX2FRef    VectorDouble -    Longitudinal slip at maximum longitudinal force at double reference vertical force
   SlipTireSlideXFRef   VectorDouble -    Longitudinal slip at sliding longitudinal force at reference vertical force
   SlipTireSlideX2FRef  VectorDouble -    Longitudinal slip at sliding longitudinal force at double reference vertical force
   F0pXFRef             VectorDouble N    Initial slope of longitudinal force at reference force
   F0pX2FRef            VectorDouble N    Initial slope of longitudinal force at  double reference force
   MuTireMaxYFRef       VectorDouble -    Normalized scaling factor for maximum lateral force at reference vertical force
   MuTireMaxY2FRef      VectorDouble -    Normalized scaling factor for maximum lateral force at double reference vertical force  
   MuTireSlideYFRef     VectorDouble -    Normalized scaling factor for sliding lateral force at reference vertical force                         
   MuTireSlideY2FRef    VectorDouble -    Normalized scaling factor for sliding lateral force at double reference vertical force                               
   SlipTireMaxYFRef     VectorDouble -    Lateral slip at maximum lateral force at reference vertical force
   SlipTireMaxY2FRef    VectorDouble -    Lateral slip at maximum lateral force at double reference vertical force
   SlipTireSlideYFRef   VectorDouble -    Lateral slip at sliding lateral force at reference vertical force
   SlipTireSlideY2FRef  VectorDouble -    Lateral slip at sliding lateral force at double reference vertical force
   F0pYFRef             VectorDouble N    Initial slope of lateral force at reference force
   F0pY2FRef            VectorDouble N    Initial slope of lateral force at  double reference force
   FRef                 VectorDouble N    Vertical reference force for the tire parameters
   FRefNormalized       VectorBool   -    Should the reference force be scaled with the static vertical tire force?
   Inertia              VectorDouble kgm² Inertia of tire
   PneumaticTrail       VectorDouble m    Pneumatic trail of tire
   ==================== ============ ==== ==============================================================================================================

The normalized factors refer to the reference vertical force or to the double reference vertical force
The input variables used by the model are tire drive and braking torques as well as the wheel angles and vertical wheel forces. All data is provided as vectors.
The model determines tire forces in the longitudinal and lateral directions as well as the wheel self aligning torques. The wheel self aligning torque is formed from the product of the tire side force and the pneumatic trail.
A linear interpolation is performed between the values for the reference force and the double reference force. If no degressive tire behavior is desired, the parameters for the double reference force must be set identically to the values for the reference force. 

All forces are scaled with the coefficient of friction from the :ref:`scenario_vehiclemodels` ("FrictionCoefficient").

All further information about the model can be found in the following sources:

https://www.tmeasy.de/ 

Rill, Georg. (2013). TMeasy -- A Handling Tire Model based on a three-dimensional slip approach. 


.. _components_motionmodel:

DynamicsMotionModel
^^^^^^^^^^^^^^^^^^^
The motion model converts the tire forces (input) into a translational and rotational movement of the vehicle. The air resistance of the vehicle is taken into account. For the dynamic calculation, the center of gravity position is taken from the :ref:`scenario_vehiclemodels` ("XPositionCOG","YPositionCOG"),
which indicates the distance of the center of gravity to the center of the rear axle. If this data is not given, the center of gravity is positioned on half wheelbase. For air resistance, the properties "AirDragCoefficient" & "FrontSurface" from the :ref:`scenario_vehiclemodels` are used.

For the equations of motion, see relevant vehicle dynamics books such as:

Kücükay, Ferit (2022), "Grundlagen der Fahrzeugtechnik", page 1067 ff
