show

Visualize trajectories

Syntax

show(planner)

show(planner,Name,Value)

axHandle = show(planner)

Description

show(planner) visualizes the reference path and trajectory from the candidates generated by the plan function. The trajectory is shown as a line plot. The plot also includes datatip mode, which can be used to visualize the feasibility vector and index of the trajectory from the TrajectoryList property.

show(planner,Name,Value) specifies additional options using one or more Name,Value pair arguments.

axHandle = show(planner) returns the axes handle of the figure used to plot the trajectory.

Examples

Optimal Trajectory Planning in Frenet Space

This example shows how to plan an optimal trajectory using a trajectoryOptimalFrenet object.

Create and Assign Map to State Validator

Create a state validator object for collision checking.

stateValidator = validatorOccupancyMap;

Create an obstacle grid map.

grid = zeros(50,100);
grid(24:26,48:53) = 1;

Create a binaryOccupancyMap with the grid map.

map = binaryOccupancyMap(grid);

Assign the map and the state bounds to the state validator.

stateValidator.Map = map;
stateValidator.StateSpace.StateBounds(1:2,:) = [map.XWorldLimits; map.YWorldLimits];

Plan and Visualize Trajectory

Create a reference path for the planner to follow.

refPath = [0,25;100,25];

Initialize the planner object with the reference path, and the state validator.

planner = trajectoryOptimalFrenet(refPath,stateValidator);

Assign longitudinal terminal state, lateral deviation, and maximum acceleration values.

planner.TerminalStates.Longitudinal = 100;
planner.TerminalStates.Lateral = -10:5:10;
planner.FeasibilityParameters.MaxAcceleration = 10;

Specify the deviation offset value close to the left lateral terminal state to prioritize left lane changes.

planner.DeviationOffset = 5;

Trajectory Planning

Initial cartesian state of vehicle.

initCartState = [0 25 pi/9 0 0 0];

Convert cartesian state of vehicle to Frenet state.

initFrenetState = cart2frenet(planner,initCartState);

Plan a trajectory from initial Frenet state.

plan(planner,initFrenetState);

Trajectory Visualization

Visualize the map and the trajectories.

show(map)
hold on
show(planner,'Trajectory','all')

Partitioning Longitudinal Terminal States in Trajectory Generation

This example shows how to partition the longitudinal terminal states in optimal trajectory planning using a trajectoryOptimalFrenet object.

Create and Assign Map to State Validator

Create a state validator object for collision checking.

stateValidator = validatorOccupancyMap; 

Create an obstacle grid map.

grid = zeros(50,100);
grid(25:27,28:33) = 1;
grid(16:18,37:42) = 1;
grid(29:31,72:77) = 1;

Create a binaryOccupancyMap with the grid map.

map = binaryOccupancyMap(grid);

Assign the map and the state bounds to the state validator.

stateValidator.Map = map;
stateValidator.StateSpace.StateBounds(1:2,:) = [map.XWorldLimits; map.YWorldLimits];

Plan and Visualize Trajectory

Create a reference path for the planner to follow.

refPath = [0,25;30,30;75,20;100,25];

Initialize the planner object with the reference path, and the state validator.

planner = trajectoryOptimalFrenet(refPath,stateValidator);

Assign longitudinal terminal state, lateral deviation, and maximum acceleration values.

planner.TerminalStates.Longitudinal = 100;
planner.TerminalStates.Lateral = -5:5:5;
planner.FeasibilityParameters.MaxAcceleration = 10;

Assign the number of partitions for the longitudinal terminal state.

planner.NumSegments = 3;

Trajectory Planning

Initial Frenet state of vehicle.

initFrenetState = zeros(1,6);

Plan a trajectory from initial Frenet state.

plan(planner,initFrenetState);

Trajectory Visualization

Visualize the map and the trajectories.

show(map)
hold on
show(planner,'Trajectory','all')
hold on

Generate Lane Boundaries

Calculate end of reference path as Frenet state.

refPathEnd = cart2frenet(planner,[planner.Waypoints(end,:) 0 0 0 0]);

Calculate lane offsets on both sides of the lateral terminal states with half lane width value.

laneOffsets = unique([planner.TerminalStates.Lateral+2.5 planner.TerminalStates.Lateral-2.5]);

Calculate positions of lanes in Cartesian state.

numLaneOffsets = numel(laneOffsets);
xRefPathEnd = ceil(refPathEnd(1));
laneXY = zeros((numLaneOffsets*xRefPathEnd)+numLaneOffsets,2);
xIndex = 0;

for laneID = 1:numLaneOffsets
    for x = 1:xRefPathEnd
        laneCart = frenet2cart(planner,[x 0 0 laneOffsets(laneID) 0 0]);
        xIndex = xIndex + 1;
        laneXY(xIndex,:) = laneCart(1:2);
    end
    xIndex = xIndex + 1;
    laneXY(xIndex,:) = NaN(1,2);
end

Plot lane boundaries.

plot(laneXY(:,1),laneXY(:,2),'LineWidth',0.5,'Color',[0.5 0.5 0.5],'DisplayName','Lane Boundaries','LineStyle','--')

Input Arguments

planner — Optimal trajectory planner in Frenet space

trajectoryOptimalFrenet object

Optimal trajectory planner in Frenet space, specified as a trajectoryOptimalFrenet object.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: 'Trajectory','all'

Parent — Axes to plot trajectory

Axes object | UIAxes object

Axes to plot trajectory, specified as the comma-separated pair consisting of 'Parent' and either an Axes or UIAxes object. See axes or uiaxes.

Trajectory — Trajectory display option

'optimal' (default) | 'all'

Trajectory display option, specified as the comma-separated pair consisting of 'Trajectory' and either 'optimal' or 'all'.

ReferencePath — Reference path display option

'on' (default) | 'off'

Reference path display option, specified as the comma-separated pair consisting of 'ReferencePath' and either 'on' or 'off'.

TrajectoryColor — Trajectory color display option

'velocity' (default) | 'acceleration' | 'cost' | 'none'

Trajectory color display option, specified as the comma-separated pair consisting of 'TrajectoryColor' and one of the following:

• 'acceleration'

• 'cost'

• 'velocity'

• 'none'

Set this property to display the specified trajectory as a color-gradient along the specified path.

Output Arguments

axHandle — Axes handle used to plot trajectory

Axes object | UIAxes object

Axes handle used to plot trajectory, returned as either an axes, or uiaxes object.

Version History

Introduced in R2019b