How to make rotate the circular pattern of balls in a while loop?

Hello! I need to make the 12 balls rotate like the blue ball they don't need to have the red mark, just move at BSF frequency, I tried doing the for loop to make the 12 balls inside the while loop but it just plots a lot of balls, also tried to draw the balls with a marker 'o' but can´t do draw the 12 balls pattern

.

close all
clear
clc
clf; 

% Entry Values

Nb = 12;      % Number of balls
BSF  =  0.222;  % Frequency (Hz)  

%% Data for Animation
    D2 = 130;                                             
    R2 = D2/2;                                                           
    d1 = 90;                                             
    d = 0.7*d1;                                              
             
     ang=linspace(0,2*pi,50);               
     xpi=R2*cos(ang);                       
     ypi=R2*sin(ang);                       
     patch(xpi,ypi,[0.90,0.90,0.90]);   % Draw static circle
    hold on
    
    % Red mark data (Hypocycloid)
    sz_mai =(d+d1)/8;     
    Ra = 65;
    ra = 10;
    ka = Ra/ra;
    ka_= ka-1;
    rh = 55;
    ramdi = (d+d1)/4;
    pmdi = plot(NaN,NaN,'-o','color', 'k', 'LineWidth', 1, 'MarkerSize', sz_mai, 'MarkerFaceColor', 'r','LineWidth', 1) ;

    % Plot Balls
    % Moving ball
    pb = plot(NaN,NaN,'-o','color', 'k', 'LineWidth', 1, 'MarkerSize',35, 'MarkerFaceColor', 'c','LineWidth', 1) ;
    % Circular Pattern
    a = linspace(0,2*pi,20);
    [x8,y8] = pol2cart(a,10);      
    fill_b=zeros(1,Nb);
    h=zeros(1,Nb);
    for angle = 1:Nb
        h(angle) = line(x8+rh*cosd(angle/Nb*360),      y8+rh*sind(angle/Nb*360)   ,'color', 'k');
        fill_b(angle) = fill(x8+rh*cosd(angle/Nb*360),      y8+rh*sind(angle/Nb*360),[0.65,0.65,0.65]);
    end  
    % Plot red Mark
    ph = plot(NaN,NaN,'-*','LineWidth', 5, 'color', 'r','MarkerFaceColor', 'r','MarkerSize', 0.01') ;
       
    %% Loop for Animation
    tic 
    while (toc < 5)
    hold on
    
    % Red Mark
    t = toc ;
    ph.XData = [rh*cos(-2*pi*BSF*t)     ra*ka_*cos(-2*pi*BSF*t) + ra*cos(ka_*2*pi*BSF*t)] ;
    ph.YData = [rh*sin(-2*pi*BSF*t)     ra*ka_*sin(-2*pi*BSF*t) - ra*sin(ka_*2*pi*BSF*t)] ;
   
    % Ball
    pb.XData = (rh*cos(-2*pi*BSF*t)) ;
    pb.YData = (rh*sin(-2*pi*BSF*t)) ;

    % 12 Gray balls
    % How to introduce the frequency BSF so that the gray circles pattern
    % rotates????
    
    drawnow
    end       
          

Answer 1

[Les Beckham]

I think you are very close to what you want.

All I had to do to make this animate is to comment out the `hold on` line and increase the end test for the while loop (I used 50 instead of 5).

Also you probably want to add an `axis equal` command before the while loop so that your circle looks like a circle.

[MSolano]

Thank you for taking the time to answer, I did what you recommended, but how should I introduce the frequency BSF for the gray balls to rotate just like the blue ball does?

I wrote:

rotate( h, [0 0 -1], BSF, [0 0 0]);

rotate(fill_b, [0 0 -1], BSF, [0 0 0]);

it's moving but not at that speed

[Les Beckham]

You are drawing the grey balls outside of the loop so they will not move. I'm not sure what you are expecting or wanting them to do. Please clarify.

[MSolano]

Yes this is it, thanks for your help. When they move the angle between each other keeps changing because the last ball doesn't move from the start point and I need the angle to be the same while moving, sorry I did not explain myself correctly.

[Les Beckham]

I'm glad that I was able to help.