How to get fmincon to work with an ode45?

Question

JV 2020-11-17

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/651248-how-to-get-fmincon-to-work-with-an-ode45

评论： Star Strider 2020-11-17

Hello fellow members of the community

I've written a code for the purpose of finding the specific initial values of an ODE of thrown particle. I wanted it be based on ode45 and fmincon function.

So much to say, it is not working and spits out an error

I'll be very thankful for any help

Cheers

Jan

PS

Here I've copied full code, that should work on any computer.

fun = @Throw; 
x0 = [10 6];
nonlcon = @Ceilling;
[v0opt, fval] = fmincon(fun,x0,[],[],[],[],[],[],nonlcon);
function dpos = Throw(t,pos)  
mu = 0.0094;
g = 10;
dpos = zeros(4,1);
dpos(1) = pos(3);
dpos(2) = pos(4);
dpos(3) = -mu * pos(3)* sqrt(pos(3)^2 + pos(4)^2);
dpos(4) = -g - mu * pos(4) * sqrt(pos(3)^2 + pos(4)^2);
end
function j = FindParam(v0)
targetPosZ = 5;
targetPosY = 2;
Opt = odeset('Events', @StopIntegration);
[t,pos] = ode45(@Throw,[0, 6],[0, 1, v0(1), v0(2)],Opt);
plane = plot(pos(:,1),pos(:,2),[targetPosZ, targetPosZ],[0 3.5],targetPosZ,targetPosY,'o');
j = (targetPosY - pos(end,2))^2 % obj. fun. = (dist. to target)^2
end
function [c,ceq] = Ceilling(v0)
ceq = [];
targetPosZ = 5;
targetPosY = 2;
Opt = odeset('Events', @StopIntegration);
[t,pos] = ode45(@Throw,[0, 10],[0, 1, v0(1), v0(2)],Opt);
h = v0(2)^2/2*g;
v = sqrt(v0(2)^2 + v0(1)^2);
c(1) = max(h - 5);    % height of the ceilling
c(2) = min(y(2) + 0); % projectile can't touch the floor
c(3) = max(v - 20);   % max velocity of 20
end
function [value, isterminal, direction] = StopIntegration(t, y)
targetPosZ = 5;              % integration stops when projectile hits the wall 
value = (y(1) > targetPosZ); 
isterminal = 1;
direction  = 0;
end