how can i move the object along a path?

clear all;
close all;
clc;
vA = [2.31; -0.55];                      % initial velocity OF 1
dt = 0.1;                              % time step for animation.
%t = 0:dt:10 ;
t = linspace(0,2*pi) ;

% get points trajectory 
%pA = zeros(2,length(t)+1) ;
pA(:,1) = [4 ;10] ;% initial position
yp = sin(pi*t) ;

for i = 2:length(t)+1                        % t is time variable
   % plot(pA(1),pA(2),'ro')            % Plot circle
    %pA(:,i) = pA(:,i-1) + vA*dt; % update position
    pA(:,i) = yp(:,i-1) + vA*dt; % update position
    %pB(:,i) = pB(:,i-1) + vB*dt; % update position
end
%plot

title('Motion animation');
%xlabel('x (m)');
%ylabel('y (m)');
h = plot(pA(1,2),pA(1,1),'cs') ;
%h = plot(pB(1,1),pB(1,2),'gp') ;


axis([min(pA(2,:)) max(pA(2,:)) min(pA(1,:)) max(pA(1,:)) ])
for i = 1:length(pA)
    set(h,'XData',pA(1,i),'YData',pA(2,i))
    %set(h,'XData',pB(1,i),'YData',pB(2,i))
    pause(.5)
end

i have a code with a particle moving along undefined path.i tried editing the code for thr e particle to move alon sine wave graph.errors are occuring.could anyone help me to edit my code to move the particle along a sine wave with constant velocity?

Answer 1

[Adam Danz]

"errors are occuring.could anyone help me to edit my code"

The code you provided runs without errors. However, the animated object leaves the axis limits. To fix that, the axis limits should be:

axis([min(pA(1,:)) max(pA(1,:)) min(pA(2,:)) max(pA(2,:)) ])

"could anyone help me to edit my code to move the particle along a sine wave with constant velocity?"

Here's a demo.

% Creat the trajectory
t=0:0.1:2*pi;
y=sin(t);
% Set up axes
axh = axes();
hold(axh,'on')
axis([0 2*pi -1 1]); %set axis limits ahead of time
xlabel('t');
ylabel('y');
% plot empty line objects (with NaN values)
line1 = plot(axh,t, nan(size(t)),'-','Color','r');
marker1 = plot(axh,nan,nan,'o','Color','r');
% loop through t and make each point appear
for k=1:numel(t)
    %marker plots
    marker1.XData = t(k);
    marker1.YData = y(k);
    
    %Line plots
    line1.YData(1:k) = y(1:k);
    
    drawnow(); 
    % pause(0.05)  %if you want to slow it down
end

The demo is a simplified version of this answer to a recent, similar question.