uavFormationMetrics

UAV trajectory ensemble for formation performance metrics

Since R2024b

Description

The uavFormationMetrics object creates a UAV formation trajectory ensemble which you can use to compute the formation performance metrics such as safety, order, connectivity, union, distance, and graph by using the object functions.

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 pair arguments. For example, uavFormationMetrics(trajObject,SafetyRadius=5) sets the safety radius to 5 meters.

Input Argument

traj — UAV trajectories

cell array of timetable

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

For each timetable, specify the time value as a N-element vector of the UAV arrival time at each position in the trajectory. In addition, specify the following variables:

Variable	Variable Name	Format
Var1	Position	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 each corresponding time.
Var2	Velocity	N-by-3 matrix in the north-east-down (NED) reference frame, in meters per second. Each row contains the velocity of the UAV at each corresponding position, [Vx Vy Vz].

Properties

SafetyRadius — Safety radius of UAV

1 (default) | nonnegative numeric scalar

Safety radius of every UAV 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 UAV

100 (default) | positive numeric scalar

Connectivity range of every UAV in the formation, specified as a positive numeric scalar in meters. This property determines the maximum allowable distance between each UAV to establish connection.

Data Types: double

MaxNumNeighbors — Maximum number of neighbors

10 (default) | nonnegative integer

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

Data Types: double

Object Functions

metrics	UAV formation performance and inter-UAV distance metrics
formationInfo	UAV formation graph and inter-UAV distance

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 perfomance 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