As for second question about including external torques I've found all I need in your tutorials on github. Thanks for that alot! As for first question looking forward to hear from you your oppinion!
Thanks in advance! среда, 10 декабря 2014 г., 0:34:04 UTC+3 пользователь aliko написал: > > Hi Jason! Thank you for quick response! > > I'm trying to describe a motion of some sort of one wheeled vehicle. It > doesn't matter what is the surface of all the terraing but it does matter > what are the unevenness on the way of the wheel. So trying to keep things > as simple as possible I think about including one more parameter - the > inclination of road on the path of the wheel no matter how it turns. The > goal is to understand how such unevenness influences dynamics. Of course > the inclination on the path should change slowly to guarantee only one > point of contact. Is such approach feasible? > > Also I would like to know how to apply the torque if I have a motor on > axis. There is a gravity force applied to center of mass in the example but > no examples on how to apply torque. > > By the way, your page is great, you making cool things!) I've learned > about pydy from it will look at it closer) > > > вторник, 9 декабря 2014 г., 23:14:11 UTC+3 пользователь Jason Moore > написал: >> >> The rolling disc examples in the docs make the assumption that the >> contact point is always located in a plane normal to gravity. If you want >> to generalize that then you need to remove that assumption. I don't think >> it is a good idea to have the surface be a function of the rotation angle. >> It could certainly make for some crazy dynamics, but it doesn't sound >> realistic. In general, you need the definition of a surface, either a >> function z=f(x, y) or a look-up table that provides z as a function of x >> and y. This surface needs to have some orientation relative to gravity >> defined. Then you must constrain the disc to not penetrate the surface. >> These kinds of constraints are probably easier by doing "soft" dynamics and >> are much hairier when you have to work out the non-deformable contact, >> especially when the disc touches the surface at more than one point. The >> general problem you describe is not at all trivial. What are you trying to >> accomplish? If I knew the scope of what you want to know maybe there is an >> easier path I can suggest. >> >> >> Jason >> moorepants.info >> +01 530-601-9791 >> >> On Tue, Dec 9, 2014 at 1:35 PM, aliko <[email protected]> wrote: >> >>> Hi! >>> I'm trying to get into mechanics module of sympy. >>> Can someone point me on a better way to add uneven terrain to example of >>> rolling disc with Kanes method ( >>> http://docs.sympy.org/latest/modules/physics/mechanics/examples/rollingdisc_example_kane.html >>> )? >>> For example I could have an inclination of terrain 'alpha' as a smooth >>> function of q3 (disc angle of rotation). Should I introduce new variable to >>> equations? Or account for alpha somewhere else? >>> >>> Great thanks in advance! >>> >>> -- >>> 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/2a37e76c-60fa-43a8-a833-c60de823f569%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/sympy/2a37e76c-60fa-43a8-a833-c60de823f569%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> 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/d8059324-be52-46dd-bf7b-a880c11debbe%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
