Hello Andreas, use ode events. This examples shows how to detect events with the bouncing ball problem. Check out the following:
function my_ode()
z0 = 10000;
dz0 = 0;
span=[0 250];
options = odeset('Events',@events);
[T,Y,Te,Ye,Ie] = ode45(@function_A,span,[z0 dz0],options);
x = linspace(0,300,2000);
plot(T,Y(:,1),'b', x,0,'g');
end
function dz = function_A(t,z)
dz = zeros(2,1);
g = 9.81;
m = 250;
lambda = 7.5*10^3;
k0 = (m*g)/((250/3.6)^2);
k = @(z)k0.*exp(-z./lambda);
dz(1) = z(2);
dz(2) = -g-(k(z(1)).*abs(z(2))*z(2))/m;
end
function [value,isterminal,direction] = events(t,y)
% Locate the time when height passes through zero in a
% decreasing direction and stop integration.
value = y(1); % Detect height = 0
isterminal = 1; % Stop the integration
direction = 0; % Negative direction only
end
