How to update constant value in Simulink while it is running?

Hello

I am currently working on AR.Drone in MATLAB. I was able to run the script to make Drone to move through the script file. However, i don't know how I can control it in real-time like keyboard pressing.

In my simulink, it has "waypoints" constant block that refer from the one of my script file. However, if I want to implement that constant block or script to control by keyboard or real time input, I wasn't able to change my waypoints during I am running my simulink to control AR.Drone.

Does anyone have code to control AR.Drone 2.0 in keyboard or any other real-time interrupting inputs?

Answer 1

[Nihar Deodhar]

The easiest way to update simulink block parameters in real time (while the model is running) is through a GUI (graphic user interface). Read matlab documentation on GUIDE functionality.

A simple illustration to create a GUI is shown below:

On the matlab command window type guide

select create a new GUI.

for our application, a simple GUI design similar to the one shown should work just fine:

It consists of a text to type in and a pushbutton to update.

Then go to view in the menu tab: > view callbacks:> CreateFcn

This will open up a matlab code that executes the GUI;

for every set of pushbutton and text block that you have edit this portion in the m file corresponding to the respective callbacks:

% --- Executes on button press in pushbutton1.

function pushbutton1_Callback(hObject, eventdata, handles)

% hObject handle to pushbutton1 (see GCBO)

% eventdata reserved - to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

A = get(handles.edit1, 'string');

set_param('simulink_file_name/subsystem_name_if_a_subsystem_exists/block_name', 'Value', A);

% those are the two main functions get and set in any GUI application.

save the code and GUI fig in the same folder as that of the simulink model.

Make sure you run the m file before starting the simulink model. There after just type in the value and hit update, the block value should change.

One important note: sometime you might have to use

set_param('simulink_file_name/subsystem_name_if_a_subsystem_exists/block_name', 'Value', num2str(A));

instead of just

set_param('simulink_file_name/subsystem_name_if_a_subsystem_exists/block_name', 'Value', A); as the constant block only accepts string inputs.