Two Subplots in an Animated For-loop Problem

Hi! I am new to Matlab and trying to learn more each day, and have some issues regarding making both of my subplots play at the same time. For the first plot, I searched for the peaks and valleys and plot them as the data recognized them as peaks/valleys, and have no problem with it. However, the second plot that I want to show is the displacement gathered from the peaks and valleys and show them when the first plot passes through the peaks/valleys. I also don't know how to incorporate the code for it, and I only know to use "comet()" on it but still not what i am looking for. My problem is in the for loop I made. Can you help me? Thanks in advance!

   figure(3);
    subplot (2,1,1)
    h = plot(time(1), mag(1)); hold on;   % Start with the first data point
    ylabel('Acceleration');    
    title('Real-time Signal Analysis'); 

    h.XDataSource = 'x1';       % Set the data source properties for dynamic updating
    h.YDataSource = 'y1';


    for i = 1:200:numel (time)
        x1 = time(1:i);
        y1 = mag(1:i);
        refreshdata(h, 'caller');
        drawnow;    

        [pks, locs] = findpeaks (mag,'MinPeakDistance',1500);
        [vks, vlocs] = findpeaks (-mag, 'MinPeakDistance',1300);
        vks = -vks;
    
        valid_vks_indices = vlocs (time(vlocs) <= x1 (end));
        valid_pks_indices = locs (time(locs) <= x1 (end));
    
        if ~isempty (valid_vks_indices)
            plot (time(valid_vks_indices), vks(ismember(vlocs, valid_vks_indices)), 'or');
        end
        if ~isempty (valid_pks_indices)
            plot (time(valid_pks_indices), pks (ismember(locs, valid_pks_indices)), 'or');
        end
        pause(0.001);
    
        subplot (2,1,2);
        xlabel ('Time'); ylabel('Displacement');
     
        for j = i
            vel = cumtrapz (time, mag);
            vel  = filtfilt (b2, a2, vel);
            disp = cumtrapz (time, vel);
            disp = filtfilt (b2, a2, disp); 

            plot (time, disp)
        end
    end

[Angelo Yeo]

I don't understand your pain points. Can you share the time, mag, a2, and b2 so that contributors including myself can understand your issue? You can save the variables into a mat file and attach it using the paperclip icon in the menu. Below is my trial to reproduce your issue. But, I still do not get what the issue is.

clear; close all; clc;
time = linspace(0, 1, 10000);
mag = rand(1,10000);
figure(3);
subplot (2,1,1)
h = plot(time(1), mag(1)); hold on;   % Start with the first data point
ylabel('Acceleration');
title('Real-time Signal Analysis');

h.XDataSource = 'x1';       % Set the data source properties for dynamic updating
h.YDataSource = 'y1';


for i = 1:200:numel (time)
    x1 = time(1:i);
    y1 = mag(1:i);
    refreshdata(h, 'caller');
    drawnow;

    [pks, locs] = findpeaks (mag,'MinPeakDistance',1500);
    [vks, vlocs] = findpeaks (-mag, 'MinPeakDistance',1300);
    vks = -vks;

    valid_vks_indices = vlocs (time(vlocs) <= x1 (end));
    valid_pks_indices = locs (time(locs) <= x1 (end));

    if ~isempty (valid_vks_indices)
        plot (time(valid_vks_indices), vks(ismember(vlocs, valid_vks_indices)), 'or');
    end
    if ~isempty (valid_pks_indices)
        plot (time(valid_pks_indices), pks (ismember(locs, valid_pks_indices)), 'or');
    end
    pause(0.001);

    subplot (2,1,2); hold on;
    xlabel ('Time'); ylabel('Displacement');

    for j = i
        vel = cumtrapz (time, mag);
        % vel  = filtfilt (b2, a2, vel);
        my_disp = cumtrapz (time, vel); % Note: "disp" is a name of built-in MATLAB function.
        % my_disp = filtfilt (b2, a2, my_disp);

        plot(time, my_disp)
    end
end

[Stella]

Hi @Angelo Yeo! Thank you for answering, I actually want to animate my dispalcement together with the magnitude (first subplot). My idea was I will plot the first peak/valley then the distance from another peak/valley will be plotted on the displacement plot? here is my code:

%raw data from XYZ direction
NormChest = readtable('TV_1.5l_Hong.csv');                   %%%get the raw data 
C = table2array(NormChest(:,1));                               
x = table2array(NormChest(:,2));
y = table2array(NormChest(:,4));
z = table2array(NormChest(:,6));
total = table2array(NormChest(:,8));
time = C(:,1);

%--------------------------------------------------------------------------
% get relative acceleration
x = x - mean(x);
y = y - mean(y);
z = z - mean(z);
total = total - mean(total);
time = time - time (1);

%--------------------------------------------------------------------------
%design for low pass filter
fs = 1000; %sampling frequency
fc = 2; %cut-off frequency
order = 1;
[b1, a1] = butter (order, fc/(fs/2));

%design for high pass filter
fcv = 0.1;
orderv = 1;
[b2, a2] = butter (orderv, fcv*2/fs, "high");

%--------------------------------------------------------------------------
% magnitude computation
mag = sqrt(x.^2+y.^2+z.^2);
figure (1)
plot (mag); axis tight;
mag  = filtfilt (b1, a1, mag);
mag = mag - mean (mag);

%--------------------------------------------------------------------------
% Initialize the plot
figure(3);
subplot (2,1,1)
h = plot(time(1), mag(1)); hold on;   % Start with the first data point
ylabel('Acceleration'); axis tight;   
title('Real-time Signal Analysis'); 

h.XDataSource = 'x1';       % Set the data source properties for dynamic updating
h.YDataSource = 'y1';


for i = 1:100:length (time)
    x1 = time(1:i-1);
    y1 = mag(1:i-1);
    refreshdata(h, 'caller');
    % drawnow;
     
    %find local min and max
    vks = find (islocalmin(mag, 'MinProminence',0.01));
    % x_vks = time (vks);
    % y_vks = mag (vks);

    pks = find (islocalmax (mag, 'MinProminence',0.01));
    % x_pks = time (pks);
    % y_pks = mag (pks); 

    if ~isempty (vks)
        plot (time (vks), mag (ismember 'or')
    end
    if ~isempty (time)
        plot (time, mag, x_pks, y_pks, 'or')
    end
    pause (0.1);
       
    subplot (2,1,2);
    xlabel ('Time'); ylabel('Displacement');
    
    for j = 1:100:length (time)
        vel = cumtrapz (time, mag);
        vel  = filtfilt (b2, a2, vel);
        disp = cumtrapz (time, vel);
        disp = filtfilt (b2, a2, disp); 
        plot (disp)
        
    end
    pause (0.1);
end
hold off;

[Angelo Yeo]

Your code doesn't work. Can you check the following lines?

plot (time (vks), mag (ismember 'or')

plot (time, mag, x_pks, y_pks, 'or')

[Stella]

Oh sorry!! This is the updated one.

 figure(3);
    subplot (2,1,1)
    h = plot(time(1), mag(1)); hold on;   % Start with the first data point
    ylabel('Acceleration');    
    title('Real-time Signal Analysis'); 
    h.XDataSource = 'x1';       % Set the data source properties for dynamic updating
    h.YDataSource = 'y1';
    
    for i = 1:200:numel (time)
        x1 = time(1:i);
        y1 = mag(1:i);
        refreshdata(h, 'caller');
        drawnow;    
        [pks, locs] = findpeaks (mag,'MinPeakDistance',1500);
        [vks, vlocs] = findpeaks (-mag, 'MinPeakDistance',1300);
        vks = -vks;
    
        valid_vks_indices = vlocs (time(vlocs) <= x1 (end));
        valid_pks_indices = locs (time(locs) <= x1 (end));
    
        if ~isempty (valid_vks_indices)
            plot (time(valid_vks_indices), vks(ismember(vlocs, valid_vks_indices)), 'or');
        end
        if ~isempty (valid_pks_indices)
            plot (time(valid_pks_indices), pks (ismember(locs, valid_pks_indices)), 'or');
        end
        pause(0.001);
    
        subplot (2,1,2);
        xlabel ('Time'); ylabel('Displacement');
     
        for j = i
            vel = cumtrapz (time, mag);
            vel  = filtfilt (b2, a2, vel);
            disp = cumtrapz (time, vel);
            disp = filtfilt (b2, a2, disp); 
            plot (time, disp)
        end
    end
    hold off;