[SciPy-Dev] Strange problem with Kanes Method and Lagrange Method

[Roberto Bucher]

I have two scripts which implement method to model a wheeled inverted 
pendulum, the first one implementing a Kanes method, the second one with 
Lagrange.

Using Kane, I obtain the right result into the "fr+frstar" variable, but 
after linearization the matrices A and B are completely wrong.

The same behavior seems to append with the Lagrange script, where after 
the Lagrange Method the

"form_lagranges_equations()" output is correct but the generated 
matrices A and B not...

In my opinion the right matrices should be:

A= np.matrix([ [0, 0, 1, 0], [0, 0, 0, 1], 
[((L_w*M_w+L_p*M_p)*g)/(L_w^2*M_w-J_w+J_p), 0, 0, 0], 
[-((L_w*M_w+L_p*M_p)*g)/(L_w^2*M_w-J_w+J_p), 0, 0, 0]] )

B = np.matrix( [0], [0], [-K_t/(L_w^2*M_w-J_w+J_p)], 
[(K_t*L_w^2*M_w+J_p*K_t)/(J_w*L_w^2*M_w-J_w^2+J_p*J_w)] )

Both scripts are attached

Thanks in advance

Best regards

Roberto

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