• Simpla

Intro#

simpla is a configurable, platooning plugin for the TraCI Python client. It manages the spontaneous formation of vehicle platoons and allows you to define specific behavior for vehicles that travel inside a platoon.

This is achieved by defining additional vehicle types which represent platooning modes, and by providing information, which type (mode) to use for normal, solitary travel, and which one to use when platooning is activated. Further, 'catch-up' modes may be specified, which are used when a potential platooning partner is farther ahead downstream.

For platooning up to four operational modes may be specified apart from the normal traveling mode (see section Configuration for the details):

• Platoon leader mode (parametrization of a vehicle driving at the front of a platoon)
• Platoon follower mode (parametrization of a vehicle driving behind another vehicle within a platoon)
• Platoon catch-up mode (parametrization of a vehicle in range of a platoon, which is feasible for joining)
• Platoon catch-up follower mode (parametrization of a vehicle traveling in a platoon, with a platoon leader in catchup mode)

It suffices to specify the platoon leader mode to use simpla. The behavior in situations corresponding to the follower mode will use the leader mode if the follower mode is not specified. The situations corresponding to the catch-up mode will use the solitary mode if no separate catch-up mode is specified. The situations corresponding to the catch-up follower mode will use the follower mode if no separate catch-up follower mode is specified.

Configuration#

The configuration of simpla is done by providing an xml-file containing obligatory and optional parameters for the application. It has a root element configuration with children tagged by the parameter name and holding attributes corresponding to the different parameter values. All possible attributes are listed in the attribute table below. A very simple configuration file could look like this (a more complete example, which serves as a template can be found in the installation directory <SUMO_HOME>/tools/simpla):

<configuration>
    <vehicleSelectors value="pkw" />
    <vTypeMap original="simple_pkw" leader="simple_pkw_as_platoon_leader"  follower="simple_pkw_as_platoon_follower"/>
    ...
</configuration>

The following table summarizes all admissible configuration parameters:

Integrating simpla into your traci script#

First of all you should ensure that the directory <SUMO_HOME>/tools is in your PYTHONPATH (See here for further explanations). To use simpla with your python script further requires the provision of a configuration file as described above. Assuming such a file named simpla.cfg is located in your working directory, all you have to do is importing simpla as a python module:

import simpla

and, after establishing a TraCI-connection to SUMO, load your configuration.

traci.start(...)
...
simpla.load("simpla.cfg")

The call to simpla.load automatically installs a TraCI-stepListener and the platoon management is executed at the end of each call to traci.simulationStep().

Utility Functions#

It is planned to add utility functions for vehicle control in simpla. They can be referenced by simpla.<function_name> Currently, only one is implemented.

openGap()#

The function has the following syntax:

openGap(vehID, desiredGap, desiredSpeedDiff, maximumDecel, duration)

The arguments are:

The methods adds a controller for the opening of a gap in front of the given vehicle, which stays active for a period of the given duration. If a leader is closer than the desiredGap, the controller tries to establish the desiredGap by inducing the given speedDifference, while not braking harder than maximumDecel. Internally, an object of the class GapCreator is created to manage the vehicle state and is added to traci as a stepListener.

Statistic Helper Functions#

There are some statistical helper functions to get information about the existing platoons listed below. They are available after starting simpla like explained above.

getAveragePlatoonLength()#

The function computes the average platoon length in terms of vehicles across all currently formed platoons:

avgLength = simpla.getAveragePlatoonLength()

getAveragePlatoonSpeed()#

The function computes the average speed of vehicles across all currently formed platoons:

avgSpeed = simpla.getAveragePlatoonSpeed()

getPlatoonLeaderIDList()#

This utility function returns the leader vehicles' IDs of all current platoons managed by simpla:

currentLeaderIDs = simpla.getPlatoonLeaderIDList()

getPlatoonIDList() and getPlatoonInfo()#

Platoons can be found by their position on the road network using the edge ID in question. The function returns IDs of platoons which currently have at least one member vehicle on the edge given by its edgeID. The platoon ID can be used to receive updates using getPlatoonInfo even when the platoon has left the edge:

platoonIDs = simpla.getPlatoonIDList(edgeID)
if len(platoonIDs) > 0:
    platoonInfo = simpla.getPlatoonInfo(platoonIDs[0])
    platoonSize = len(platoonInfo["members"])

The function getPlatoonInfo returns a dictionary of values regarding the platoon, using the keys from the table below:

getPlatoonID()#

This utility function allows to check if a given vehicle is part of a platoon in simpla. If the vehicle given by its ID is controlled by simpla, the function returns the numerical platoon ID (-1 otherwise). The platoon ID can be used as an input to getPlatoonInfo to get information about the platoon structure.

vehID = "myExampleVehicle"
platoonID = simpla.getPlatoonID(vehID)

Example#

An example can be downloaded from the nightly test suite This can be executed by calling python runner.py