getReferencePosition

Get reference position of vehicle

Since R2024b

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Syntax

position = getReferencePosition(vehicle,vehicleBodyLocation)

Description

position = getReferencePosition(vehicle,vehicleBodyLocation) gets the reference position position of the vehicle vehicle at the specified vehicle body location vehicleBodyLocation.

example

Examples

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Open Live Script

Create a driving scenario object.

scenario = drivingScenario;

Add road and lane segments to the driving scenario.

roadCenters = [10.3 25.94 0;
              34.8 0.45 0;
              19.1 -21.74 0];
laneSpecification = lanespec(2,Width=5);
road(scenario,roadCenters,Lanes=laneSpecification,Name="Road")
ans = 
  Road with properties:

           Name: "Road"
         RoadID: 1
    RoadCenters: [3×3 double]
      RoadWidth: 10.1500
      BankAngle: [3×1 double]
        Heading: [3×1 double]

Add a vehicle to the scenario, and specify waypoint positions and speeds. Use the waypoints and speeds to create a trajectory for the vehicle, with reference to the front axle for steering.

egoVehicle = vehicle(scenario, ...
    ClassID=2, ...
    Length=8.2, ...
    Width=2.5, ...
    Height=3.5, ...
    Position=[21.4185032445924 18.4409098505372 0.01], ...
    RearOverhang=1, ...
    FrontOverhang=0.9, ...
    Mesh=driving.scenario.truckMesh, ...
    Name="Truck");
waypoints = [21.41 18.44 0.01;
            29.9 12.34 0.01;
            35.3 5.85 0.01;
            36.99 0.75 0.01;
            36.4 -6.25 0.01;
            33.2 -12.24 0.01;
            28.6 -17.14 0.01];
speed = [30 30 30 30 30 30 30]';
trajectory(egoVehicle,waypoints,speed,ReferenceSteerPosition="front-axle")

Plot the scenario, run the simulation, and get the position of the vehicle at its front-axle location and rear-axle location for each frame.

plot(scenario,Waypoints="on",RoadCenters="on",ShowRearAxle="on")
frames = 1;
while advance(scenario)
    frontAxlePosition(frames,:) = getReferencePosition(egoVehicle,"front-axle");
    rearAxlePosition(frames,:) = getReferencePosition(egoVehicle,"rear-axle");
    frames = frames + 1;
    pause(0.1)
end

Display the position of the vehicle at its front-axle location and rear-axle location for the first few frames. Units are in meters.

head(frontAxlePosition,5)
   21.6616   18.2765    0.0100
   21.9131   18.1130    0.0100
   22.1645   17.9494    0.0100
   22.4158   17.7856    0.0100
   22.6670   17.6215    0.0100

head(rearAxlePosition,5)
   16.3788   21.7091    0.0100
   16.6304   21.5457    0.0100
   16.8819   21.3822    0.0100
   17.1335   21.2187    0.0100
   17.3850   21.0552    0.0100

Plot the wheel base, and position of the vehicle at its front-axle location and rear-axle location.

clf
plot(frontAxlePosition(:,2),frontAxlePosition(:,1))
hold on
plot(rearAxlePosition(:,2),rearAxlePosition(:,1))
i = 1;
while i <= length(frontAxlePosition(:,1))
    f = scatter(frontAxlePosition(i,2),frontAxlePosition(i,1));
    r = scatter(rearAxlePosition(i,2),rearAxlePosition(i,1));
    f.MarkerFaceColor = "#4DBEEE";
    r.Marker = "*";
    r.MarkerEdgeColor = "#D95319";
    plot([frontAxlePosition(i,2),rearAxlePosition(i,2)],[frontAxlePosition(i,1),rearAxlePosition(i,1)],"k");
    i = i + 20;
end
legend(["Front Axle Trajectory","Rear Axle Trajectory","","","Wheelbase"])
xlim([-20 30])
ylim([0 50])

Input Arguments

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Vehicle belonging to a drivingScenario object, specified as a Vehicle object. To create a Vehicle object, use the vehicle function.

Vehicle body location for which to obtain the vehicle reference position, specified as one of these options: "front-bumper", "rear-bumper", "front-axle", or "rear-axle".

Data Types: string

Output Arguments

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Reference position of the vehicle, returned as a three-element row vector in the form [x y z]. Units are in meters. The vehicleBodyLocation input argument specifies the vehicle body location for which to obtain the vehicle reference position position.

Data Types: single | double

Version History

Introduced in R2024b

See Also

Objects

Functions

Topics