inflationCollisionChecker

Plan a vehicle path to a narrow parking spot by using the optimized rapidly exploring random tree (RRT*) algorithm. Try different collision-checking configurations in the costmap used by the RRT* path planner.

Load and display a costmap of a parking lot. The costmap is a vehicleCostmap object. By default, vehicleCostmap uses a collision-checking configuration that inflates obstacles based on a radius of only one circle enclosing the vehicle. The costmap overinflates the obstacles (the parking spot boundaries).

data = load('parkingLotCostmap.mat');
costmap = data.parkingLotCostmap;

figure
plot(costmap)
title('Collision Checking with One Circle')

Use inflationCollisionChecker to create a new collision-checking configuration for the costmap.

Specify the collision-checking configuration in the CollisionChecker property of the costmap.

vehicleDims = vehicleDimensions(4.5,1.7);  % 4.5 m long, 1.7 m wide
numCircles = 3;
ccConfig = inflationCollisionChecker(vehicleDims,numCircles);
costmap.CollisionChecker = ccConfig;

Display the costmap with the new collision-checking configuration. The inflated areas are reduced.

figure
plot(costmap)
title('Collision Checking with Three Circles')

Define a planning problem: a vehicle starts near the left entrance of the parking lot and ends in a parking spot.

startPose = [11 10 0];   % [meters, meters, degrees]
goalPose = [31.5 17 90]; 

Use a pathPlannerRRT object to plan a path to the parking spot. Plot the planned path.

planner = pathPlannerRRT(costmap);
refPath = plan(planner,startPose,goalPose);

hold on
plot(refPath)
hold off

Create a collision-checking configuration for a costmap. Manually specify the circle centers so that they fully enclose the vehicle.

Define the dimensions of a vehicle by using a vehicleDimensions object.

length = 5; % meters
width = 2; % meters
vehicleDims = vehicleDimensions(length,width);

Define three circle centers and the inflation radius to use for collision checking. Place one center at the vehicle's midpoint. Offset the other two centers by an equal amount on either end of the vehicle.

distFromSide = 0.175;
centerPlacements = [distFromSide 0.5 1-distFromSide];
inflationRadius = 1.2;

Create and display the collision-checking configuration.

ccConfig = inflationCollisionChecker(vehicleDims, ...
    'CenterPlacements',centerPlacements,'InflationRadius',inflationRadius);

figure
plot(ccConfig)

In this configuration, the corners of the vehicle are not enclosed within the circles. To fully enclose the vehicle, increase the inflation radius. Display the updated configuration.

ccConfig.InflationRadius = 1.3;
plot(ccConfig)

Use this collision-checking configuration to create a 10-by-20 meter costmap.

costmap = vehicleCostmap(10,20,0.1,'CollisionChecker',ccConfig);