How to Control Simulink from Matlab during Simulation

I have written a control scheme using Simulink. I need to control it using Matlab. I am currently using fixed values for variables such as the degree of deflection of aerodynamic control surfaces. I need to be able to change the values of those variable as I am flying the aircraft (running Simulink simulation). (dA might be change of Aeleron. dR might be change of rudder. Etc.) How do I make these dX values variable? How do I replace the fixed dX values in the program with variables that can be changed? How do I make the dX values variable? This includes throttle settings for speed that may change. Can you please asnwer my question specifically? I really need a usable answer. It would be helpful if I could simply use left and right arrow keys to control motion left or right and the up down arrow keys to control moiton that is up or down. Maybe F and S keys for faster and slower? Some means of displaying how far I'm driving the variable toward its max or min value on screen would also be very useful.

Answer 1

[Sam Chak]

Hi @DJ V

I am unable to address all questions in a single post, as some require knowledge of aerospace engineering. However, to achieve the functionality of increasing and decreasing the value of a variable x in MATLAB based on key presses, you may consider the following approach:

%% create a function file for "keyPressExample.m"
function keyPressExample()
    % Initialize variable
    x           = 0;        % Initial value
    increment   = 1;        % Amount to change x
    isFPressed  = false;    % Flag for F key
    isSPressed  = false;    % Flag for S key

    % Create a fig
    fig = figure('KeyPressFcn', @keyPress, 'KeyReleaseFcn', @keyRelease);

    % Start a timer to update x
    t = timer('ExecutionMode', 'fixedRate', 'Period', 0.1, 'TimerFcn', @(~,~) updateX());

    start(t);

    % Nested function to handle key press
    function keyPress(~, event)
        switch event.Key
            case 'f'
                isFPressed = true;
            case 's'
                isSPressed = true;
        end
    end

    % Nested function to handle key release
    function keyRelease(~, event)
        switch event.Key
            case 'f'
                isFPressed = false;
            case 's'
                isSPressed = false;
        end
    end

    % Nested function to update x
    function updateX()
        if isFPressed
            x = x + increment;  % Increase x
        elseif isSPressed
            x = x - increment;  % Decrease x
        end
        disp(x);                % Display the current value of x
    end

    % Clean up when figure is closed
    set(fig, 'CloseRequestFcn', @(src, event) closeFigure(src, t));
end


%% create a function file for "closeFigure.m" (Click the "×" button to close)
function closeFigure(fig, t)
    stop(t);
    delete(t);
    delete(fig);
end

[DJ V]

Okay, why are you opening and closing a figure? I merely need to transmit data to simulink. How do I establish when I connect to simulink to transmit variable value updates? How do I establish when Simuink is done so I can collect the results, or do I merely update periodically? How do I select linking variables for the variables that I'm changing in simulink? In other words, how do I choose the block or variable type to accept the data I'm sending simulink? I suppose the block opening and closing is because I need to update the simulation in matlab (the animation) as it runs. How do I periodically accomplish this? Another timer? Keep in mind that I need to download data from Simulink to update the Matlab screen. Do I pause simulink while doing that?

Answer 2

[Paul]

Perhaps dashboard blocks would be helpful.