I am struggling to modify the "Highway lane change" example.

I am trying to implement the "Highway lane change" example with my own controller. Initially I designed my controller such that if I can provide the controller a reference path ( in the form of a N*2 matrix) the controller will be able to follow that path. Now I want to extend my project such that the reference path will be generated autonomously with the help of sensor fusion. I can see the similar thing has been done in the "Highway lane change" project. But for my controller I need to extract the reference X and Y values. But I am struggling to find those 2 values. I have tries with a matlab function block with the following code -

function [X_ref, Y_ref] = extractWaypoints(TrajectoryInfo)

% Extract X and Y waypoints from the planned trajectory

optimalTrajIndex = TrajectoryInfo.OptimalTrajectoryIndex;

trajectory = TrajectoryInfo.GlobalTrajectory(optimalTrajIndex).Trajectory;

% Extract X and Y positions

X_ref = trajectory(:, 1);

Y_ref = trajectory(:, 2);

end

But with this I am getting the error, "Error:'Input Port 1' of 'MotionPlanner/Ref_waypoints' expects a bus but receives a nonbus signal from 'Output Port 1' of 'MotionPlanner/MATLAB Function2'."

I am not sure how to work on this example.

Answer 1

[Satwik]

Hi Atulan,

I understand that the error message indicates that the MATLAB Function block is expected to output a bus signal, but it is currently outputting a non-bus signal. The following steps should be helpful in resolving the issue:

1. Understand the Input and Output Requirements: Verify the structure of ‘TrajectoryInfo’ to ensure you are accessing the correct fields. It should be a bus object if your model expects a bus signal.

2. Define a Bus Object: If ‘TrajectoryInfo’ is a bus, define a corresponding bus object in MATLAB that matches the structure of the signal. Here is an example of how to define bus object for the output:

% Define Bus Elements
elems(1) = Simulink.BusElement;
elems(1).Name = 'X_ref';
elems(1).Dimensions = [N, 1]; % Set N to the appropriate size

elems(2) = Simulink.BusElement;
elems(2).Name = 'Y_ref';
elems(2).Dimensions = [N, 1]; % Set N to the appropriate size

% Create Bus Object
refWaypointsBus = Simulink.Bus;
refWaypointsBus.Elements = elems;

% Assign the Bus Object to the MATLAB Function Block
set_param('YourModelName/MotionPlanner/Ref_waypoints', 'OutDataTypeStr', 'Bus: refWaypointsBus');

Please refer to the following documentation for more information on ‘Simulink.Bus’:

https://www.mathworks.com/help/simulink/slref/simulink.bus.html

3. Adjust the MATLAB Function:

Make sure the MATLAB function outputs a structure that conforms to the defined bus:

function refWaypoints = extractWaypoints(TrajectoryInfo)
% Extract X and Y waypoints from the planned trajectory
optimalTrajIndex = TrajectoryInfo.OptimalTrajectoryIndex;
trajectory = TrajectoryInfo.GlobalTrajectory(optimalTrajIndex).Trajectory;

% Create a structure to match the bus
refWaypoints.X_ref = trajectory(:, 1);
refWaypoints.Y_ref = trajectory(:, 2);
end

I hope this helps!