How to use ode45 in this case?

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Elie Hatem on 28 May 2021

Edited: Elie Hatemon 28 May 2021

Accepted Answer: Torsten

Hello,

I have the variable ydd (y double dot) that I want to integrate twice to get the variable y.

The formula of ydd is:

ydd = -tan(phi).*(zdd + gravity)

where phi , zdd are vectors of size (1 xn) containing different angles and accelerations at each time instant.

And, gravity 也是一个向量的大小 (1 xn) containing a constant value (which is 9.81) repeated n times.

So, ydd is also a (1 xn) vector containing different accelerations at each time instant.

How can I use ode45 to integrate ydd twice?

Thank you for taking the time to read my question.

Torsten on 28 May 2021

Edited:Torsten on 28 May 2021

ydot = y'(t0) + cumtrapz(t,-tan(phi).*(zdd+gravity));

y = y(t0) + cumtrapz(t,ydot),

plot(t,y)

where t is your (1xn) vector of times (t0,...,t_(n-1)) and y(t0) and y'(t0) are initial conditions (position and velocity at t=t0, respectively).

Elie Hatem on 28 May 2021

Alright I will check and compare both solutions. Thanks for your help!

R2020a

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