interpolate

Interpolate path based on propagator step size

Since R2021b

Syntax

interpolate(pathObj)

Description

interpolate(pathObj) evaluates the path based on the ControlStepSize property of the nav.StatePropagator object in the StatePropagator property of the control path pathObj, and adds all intermediate points to the control path.

Examples

Combine Two Kinodynamic Paths with Controls for Mobile Robot

Set State and State Propagator Parameters

Load a ternary map matrix and create an occupancyMap object.

load("exampleMaps","ternaryMap")
map = occupancyMap(ternaryMap,10);

Create a state propagator for a bicycle kinematic model using the map.

propagator = mobileRobotPropagator(Environment=map);

Set the state bounds on the state space based on the map world limits.

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

Plan Path

Create the path planner from the state propagator.

planner = plannerControlRRT(propagator);

Specify the start and goal states.

start = [10 15 0];
goal  = [40 30 0];

Plan a path between the states. For repeatable results, reset the random number generator before planning.

rng("default")
path = plan(planner,start,goal);

Check the total elapsed duration of the control path.

pathDuration(path)

ans = 
102.4000

Interpolate the path to the control step size of the propagator.

interpolate(path)

Visualize the path.

figure
show(map)
hold on
plot(start(1),start(2),"rx")
plot(goal(1),goal(2),"go")
plot(path.States(:,1),path.States(:,2),"b")
hold off

Plan Return Path

Plan a second path from the end of the previous path location back to the start.

path2 = plan(planner,path.States(end,:),start);

Check the total elapsed duration of the second path.

pathDuration(path2)

ans = 
100.3000

Visualize the path.

figure
show(map)
hold on
plot(start(1),start(2),"rx")
plot(goal(1),goal(2),"go")
plot(path2.States(:,1),path2.States(:,2),"m")
hold off

Combine Paths

Extract the sequence of motions from the second path.

states = path2.States(2:end,:);
controls = path2.Controls;
targets = path2.TargetStates;
durations = path2.Durations;

Append this sequence to the end of the first path.

append(path,states,controls,targets,durations)

Interpolate the new segments in the original path.

interpolate(path)

Check the total elapsed duration of the final path.

pathDuration(path)

ans = 
102.4000

Visualize the path.

figure
show(map)
hold on
plot(start(1),start(2),"rx")
plot(goal(1),goal(2),"go")
plot(path.States(:,1),path.States(:,2),"b")
hold off

Input Arguments

pathObj — Control path object

navControlPath object

Control path, specified as a navPathControl object.

Data Types: double

Version History

Introduced in R2021b