uavFormationMetrics

UAV trajectory ensemble for formation performance metrics

Since R2024b

Description

The uavFormationMetrics object creates a UAV formation trajectory ensemble that you can use to compute the formation performance metrics for a UAV formation that consist of safety, order, connectivity, union, distance, and graph.

Creation

Syntax

trajectoryEnsemble = uavFormationMetrics(traj)

trajectoryEnsemble = uavFormationMetrics(traj,Name=Value)

Description

trajectoryEnsemble = uavFormationMetrics(traj) creates a UAV trajectory ensemble object from the specified UAV trajectories traj.

trajectoryEnsemble = uavFormationMetrics(traj,Name=Value) specifies properties using one or more name-value arguments. For example, uavFormationMetrics(trajObject,SafetyRadius=5) sets the safety radius to 5 meters.

Input Arguments

traj — Trajectories of UAVs in formation

cell array of timetable

Trajectories of UAVs in the formation, specified as cell array of timetable, where each timetable stores the trajectory of a UAV in the formation.

Each timetable must consist of a time value, specified as an N-element vector , where N is the number of positions in the trajectory and each value is the arrival time of the UAV at the corresponding position, and these variables:

Variable	Description
Var1	Position, specified as a N-by-3 matrix in the north-east-down (NED) reference frame, in meters. Each row contains the [X Y Z] position of the UAV at the corresponding time.
Var2	Velocity, specified as an N-by-3 matrix in the north-east-down (NED) reference frame, in meters per second. Each row contains the[Vx Vy Vz] velocity of the UAV at the corresponding position.

Properties

SafetyRadius — Safety radius of UAV

1 (default) | positive numeric scalar

Safety radius of the UAVs in the formation, specified as a positive numeric scalar in meters. In a formation flight, a collision occurs if the distance between any two UAVs is less than twice of this radius.

Data Types: double

ConnectivityRange — Maximum connection range of UAVs

100 (default) | positive numeric scalar

Maximum connection range of the UAVs in the formation, specified as a positive numeric scalar in meters. This property determines the maximum distance at which UAVs can establish connections to one another.

Data Types: double

MaxNumNeighbors — Maximum number of neighbors

10 (default) | nonnegative integer

Maximum number of neighbors of each UAV in the formation, specified as a nonnegative integer. This property specifies the maximum number of other UAVs that each UAV can connect to.

Data Types: double

Object Functions

metrics	Get UAV formation performance and inter-UAV distance metrics
formationInfo	Get UAV formation graph, positions, and inter-UAV distances

Examples

Visualize and Obtain Performance Metrics of UAV Formation

Specify the number of UAVs in a UAV formation, and create the timestamps for the UAV trajectories.

% Number of UAVs in the formation
numUAV = 4;

% Timestamps
time = [0; 1];

Specify the position of each UAV in ENU frame in meters at 0 and 1 seconds.

uav1_position = [1 0 10;
                1 0 10.5];
uav2_position = [0.5 0.8 10;
                0.5 1.8 11];
uav3_position = [1.5 1 10;
                1.5 1.8 11];
uav4_position = [2 0 10;
                1.5 0 10.5];

Specify the velocity of each UAV in ENU frame in m/s at 0 and 1 seconds.

uav1_velocity = [0 0 0.5; 
                1 0 0];
uav2_velocity = [0 1 1;
                1 0 0];
uav3_velocity = [0 1 1;
                1 0 0];
uav4_velocity = [0 0 0.5;
                1 0 0];

Store the trajectory of each UAV in a timetable, and store the timetables in a cell array.

trajData1=timetable(seconds(time),uav1_position,uav1_velocity,VariableNames={'Position','Velocity'});
trajData2=timetable(seconds(time),uav2_position,uav2_velocity,VariableNames={'Position','Velocity'});
trajData3=timetable(seconds(time),uav3_position,uav3_velocity,VariableNames={'Position','Velocity'});
trajData4=timetable(seconds(time),uav4_position,uav4_velocity,VariableNames={'Position','Velocity'});

Create a UAV trajectory ensemble object. Specify the safety radius as 0.25 meters, a maximum connectivity range of 1.5 meters, and a maximum number of neighbors of 5.

trajectoryEnsemble = uavFormationMetrics({trajData1,trajData2,trajData3,trajData4},SafetyRadius=0.25,ConnectivityRange=1.5,...
    MaxNumNeighbors=5);

Obtain the performance and distance metrics of the UAV formation.

[perfMetrics,distMetrics] = metrics(trajectoryEnsemble);

Plot the formation performance metrics.

stackedplot(perfMetrics)
grid on
title("Formation Performance Metrics")

Plot the distance performance metrics.

stackedplot(distMetrics)
grid on
title("Distance Metrics")

Obtain the UAV formation information.

info = formationInfo(trajectoryEnsemble);

Plot the UAV formation at the initial time step.

% Create edge label for UAV distance at 0 seconds
edgeLabel0 = info.FormationGraph{1}.Edges.Weight;

% Plot the formation at 0 seconds
plot(info.FormationGraph{1},EdgeLabel=edgeLabel0, ...
    XData=info.PositionX(1,:),YData=info.PositionY(1,:), ...
    ZData=info.PositionZ(1,:));

% Add title labels to each axis
title("UAV Formation at t = 0 seconds")
xlabel("East")
ylabel("North")
zlabel("Up")

Plot the UAV formation after movement at t = 1 second. In this time, some UAVs are out of the connectivity range and form 2 connected subgroups.

% Create edge label for UAV distance at 1 second
edgeLabel1 = info.FormationGraph{2}.Edges.Weight;

% Plot the formation at 1 second
plot(info.FormationGraph{2},EdgeLabel=edgeLabel1, ...
    XData=info.PositionX(2,:),YData=info.PositionY(1,:), ...
    ZData=info.PositionZ(2,:)); 

% Add labels to each axis
title("UAV Formation at t = 1 second")
xlabel("East")
ylabel("North")
zlabel("Up")

Obtain the inter-UAV distance for all UAV pairs in the formation at t = 1 second.

info.InterUAVDistance{2}

ans=6×2 table
    UAVPair    Distance
    _______    ________

    1    2      1.9339 
    1    3      1.9339 
    1    4         0.5 
    2    3           1 
    2    4       2.119 
    3    4      1.8682 

Version History

Introduced in R2024b