advance

Advance driving scenario simulation by one time step

Syntax

isRunning = advance(scenario)

Description

isRunning = advance(scenario) advances a driving scenario simulation by one time step. To specify the step time, use the SampleTime property of the input drivingScenario object, scenario. The function returns the status, isRunning, of the simulation.

Examples

Advance Driving Scenario Simulation

Create a driving scenario. Use the default sample time of 0.01 second.

scenario = drivingScenario;

Add a straight, 30-meter road to the scenario. The road has two lanes.

roadCenters = [0 0; 30 0];
road(scenario,roadCenters,'Lanes',lanespec(2));

Add a vehicle that travels in the left lane at a constant speed of 30 meters per second. Plot the scenario before running the simulation.

v = vehicle(scenario);
waypoints = [5 2; 25 2];
speed = 30; % m/s
trajectory(v,waypoints,speed)

plot(scenario)

Call the advance function in a loop to advance the simulation one time step at a time. Pause every 0.01 second to observe the motion of the vehicle on the plot.

while advance(scenario)
    pause(0.01)
end

Show Target Outlines in Driving Scenario Simulation

Create a driving scenario and show how target outlines change as the simulation advances.

Create a driving scenario consisting of two intersecting straight roads. The first road segment is 45 meters long. The second straight road is 32 meters long and intersects the first road. A car traveling at 12.0 meters per second along the first road approaches a running pedestrian crossing the intersection at 2.0 meters per second.

scenario = drivingScenario('SampleTime',0.1,'StopTime',1);
road(scenario,[-10 0 0; 45 -20 0]);
road(scenario,[-10 -10 0; 35 10 0]);
ped = actor(scenario,'Length',0.4,'Width',0.6,'Height',1.7);
car = vehicle(scenario);
pedspeed = 2.0;
carspeed = 12.0;
trajectory(ped,[15 -3 0; 15 3 0],pedspeed);
trajectory(car,[-10 -10 0; 35 10 0],carspeed);

Create an ego-centric chase plot for the vehicle.

chasePlot(car,'Centerline','on')

Create an empty bird's-eye plot and add an outline plotter and lane boundary plotter. Then, run the simulation. At each simulation step:

• Update the chase plot to display the road boundaries and target outlines.

• Update the bird's-eye plot to display the updated road boundaries and target outlines. The plot perspective is always with respect to the ego vehicle.

bepPlot = birdsEyePlot('XLim',[-50 50],'YLim',[-40 40]);
outlineplotter = outlinePlotter(bepPlot);
laneplotter = laneBoundaryPlotter(bepPlot);
legend('off')

while advance(scenario)
    rb = roadBoundaries(car);
    [position,yaw,length,width,originOffset,color] = targetOutlines(car);    
    plotLaneBoundary(laneplotter,rb)
    plotOutline(outlineplotter,position,yaw,length,width, ...
        'OriginOffset',originOffset,'Color',color)
    pause(0.01)
end

Simulate Car Traveling on S-Curve

Simulate a driving scenario with one car traveling on an S-curve. Create and plot the lane boundaries.

Create the driving scenario with one road having an S-curve.

scenario = drivingScenario('StopTime',3);
roadcenters = [-35 20 0; -20 -20 0; 0 0 0; 20 20 0; 35 -20 0];

Create the lanes and add them to the road.

lm = [laneMarking('Solid','Color','w'); ...
    laneMarking('Dashed','Color','y'); ...
    laneMarking('Dashed','Color','y'); ...
    laneMarking('Solid','Color','w')];
ls = lanespec(3,'Marking',lm);
road(scenario,roadcenters,'Lanes',ls);

Add an ego vehicle and specify its trajectory from its speed and waypoints. The car travels at 30 meters per second.

car = vehicle(scenario, ...
    'ClassID',1, ...
    'Position',[-35 20 0]);
waypoints = [-35 20 0; -20 -20 0; 0 0 0; 20 20 0; 35 -20 0];
speed = 30;
trajectory(car,waypoints,speed);

Plot the scenario and corresponding chase plot.

plot(scenario)

chasePlot(car)

Run the simulation loop.

1. Initialize a bird's-eye plot and create an outline plotter, left-lane and right-lane boundary plotters, and a road boundary plotter.

2. Obtain the road boundaries and rectangular outlines.

3. Obtain the lane boundaries to the left and right of the vehicle.

4. Advance the simulation and update the plotters.

bep = birdsEyePlot('XLim',[-40 40],'YLim',[-30 30]);
olPlotter = outlinePlotter(bep);
lblPlotter = laneBoundaryPlotter(bep,'Color','r','LineStyle','-');
lbrPlotter = laneBoundaryPlotter(bep,'Color','g','LineStyle','-');
rbsEdgePlotter = laneBoundaryPlotter(bep);
legend('off');
while advance(scenario)
    rbs = roadBoundaries(car);
    [position,yaw,length,width,originOffset,color] = targetOutlines(car);
    lb = laneBoundaries(car,'XDistance',0:5:30,'LocationType','Center', ...
        'AllBoundaries',false);
    plotLaneBoundary(rbsEdgePlotter,rbs)
    plotLaneBoundary(lblPlotter,{lb(1).Coordinates})
    plotLaneBoundary(lbrPlotter,{lb(2).Coordinates})
    plotOutline(olPlotter,position,yaw,length,width, ...
        'OriginOffset',originOffset,'Color',color)
end

Input Arguments

scenario — Driving scenario

drivingScenario object

Driving scenario, specified as a drivingScenario object.

Output Arguments

isRunning — Run state of simulation

1 | 0

Run state of the simulation, returned as logical 1 (true) or 0 (false).

• If isRunning is 1, the simulation is running.

• If isRunning is 0, the simulation has stopped running.

A simulation runs until at least one of these conditions are met:

• The simulation time exceeds the simulation stop time. To specify the stop time, use the StopTime property of scenario.

• Any actor or vehicle reaches the end of its assigned trajectory. The assigned trajectory is specified by the most recent call to the trajectory function.

The advance function updates actors and vehicles only if they have an assigned trajectory. To update actors and vehicles that have no assigned trajectories, you can set the Position, Velocity, Roll, Pitch, Yaw, or AngularVelocity properties at any time during simulation.