How to find the time and partial derivative?

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RoBoTBoY 2020-12-22

评论： RoBoTBoY 2020-12-22

Hello!

I have this:

How to represent the above in matlab in order to find the partial derivative w.r.t. q1_dot, that is the below

And after that i want to find the time derivative from the above.

Thanks in advance

RoBoTBoY 2020-12-22

Maybe this?

Walter Roberson 2020-12-22

syms q1(t) q2(t) l1 l2 m I

K = 1/2*m*diff(q1(t),t)^2+1/2*(m*l2^2+I)*diff(q2(t),t)^2-m*diff(q1(t),t)*l2*sin(q2)*diff(q2(t),t)

K(t) =

syms Q1_dot

Ks = subs(K(t), diff(q1), Q1_dot)

Ks =

dK_q1_dot = diff(Ks, Q1_dot)

dK_q1_dot =

dK_q1_dot_dt = diff(dK_q1_dot, t)

dK_q1_dot_dt =

Alan Stevens 2020-12-22

You don't really need the power of MATLAB here; elementary calculus will do:

RoBoTBoY 2020-12-22

Yes indeed, but i want the power of MATLAB to verify my maths.

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