Some notes: - Since you specified your kinematic relations as u = q', then you should set your velocities with u instead of q, for example: p1.set_vel(N, u1d * N. x) - I doubt that you need to specify any velocity constraints and thus you will not have any dependent speeds. You've defined ell as some new coordinate, but do not add it as an independent coordinate. I don't think this is correct. It will likely work if you just remove the coordinate constraint stuff.
Jason moorepants.info +01 530-601-9791 On Mon, Jan 12, 2015 at 5:12 AM, Guillaume Gay <[email protected]> wrote: > > Hi, > > I'm trying to use sympy KanesMethod to model biological assemblies (i.e. > the mitotic spindle). > > Molecular motors in biology follow linear force velocity relationships, > such that F = F_max(1 -ld/V_max) where ld is the relative speed of the two > points on which the force is applied (distant of l). > > I strugle to implement this in the Kanes formalism... I tried various > things: > * constraint the generalized speed as u = (V_max - ld) > * declare the above relation in the kinetic differential equation > > In both cases, the `to_linearizer` method rises a: > > ValueError: Cannot have dynamicsymbols outside dynamic forcing vector. > > * use directly ld as the speed, and declare it as auxiliary > > Then I have a shape mismatch when I try to linearize. > > Bellow is a notebook with the code: > > http://nbviewer.ipython.org/github/glyg/Notebooks/blob/ > master/kt_sim/minimum%20Linear%20Force%20Velocity.ipynb > > > Best, > > Guillaume > > -- > Guillaume Gay, PhD > > http://damcb.com > > 43 rue Horace Bertin > 13005 Marseille > > +33 953 55 98 89 > +33 651 95 94 00 > > n°SIRET 751 175 233 00020 > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sympy. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/sympy/54B3C853.5090405%40gmail.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAP7f1Ai5T8tqih9V4zgzHh10m-EG7EkYFMZvo56wQTmuWNBKrg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
