So if I just used a torque motor without the PID controllers, there would still be some "wiggling" to the motor joint?
On Tuesday, August 16, 2022 at 8:43:59 AM UTC-4 Alessandro Tasora ([email protected]) wrote: > Yes, the reason is the one that you quoted. > Both ChLinkMotorSpeed and ChLinkMotorAngle are Rheonomic (or "Rheonomous" > in some literature), that is: the position is strictly enforced by some > function of time, in a "geometric sense". Hence they don't allow compliance > if they conflict with other constraints, and results can be impredictable. > > Only by using force- or torque-based motors like ChLinkMotorTorque (and > adding PID controllers for keeping approximately the position via feedback > loops, for instance) you can simulate that hard-stop scenario you need. But > at the cost of more complication, and some compliance and latency and > reduced bandwidth - just like realistic servo motors, by the way. > > Best regards > Alessandro Tasora > > ------------------------------ > *Da:* [email protected] <[email protected]> per conto > di Alex Teti <[email protected]> > *Inviato:* martedì 16 agosto 2022, 09:33 > *A:* ProjectChrono > *Oggetto:* [chrono] Re: Strange Motor Collision Behavior > > " > *Note: this is a rheonomic motor, i.e. it generates the > motion geometrically by strictly enforcing the speed constraint; therefore > no compliance is allowed and this means that if the rotating body hits some > hard contact, the solver might give unpredictable oscillatory or diverging > results because of the contradiction.*" > > Is THIS the underlying reason? I don't think I can even *say* "rheonomic"! > > On Tuesday, August 16, 2022 at 3:10:33 AM UTC-4 Alex Teti wrote: > >> I was wondering what would happen if a motorized object (a rectangle) >> collided with a fixed object (a cube). >> >> To my surprise, the result was either >> A) The motorized object (rectangle) being pushed away from its >> constrained location >> or >> B) The stationary object (cube) being pushed away from its constrained >> location >> >> If I made the cube fixed (*cube->SetBodyFixed(true);*) then the cube >> would remain stationary and the rectangle would move. >> >> If I used a *ChLinkLockLock* link to link the cube and floor, the cube >> would be pushed away (and then slowly drift back). >> >> Is there a way to make both the objects stationary after they collide, >> like if some metal object got stuck in a turbine and jammed it? >> > -- > You received this message because you are subscribed to the Google Groups > "ProjectChrono" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/projectchrono/0346f694-3438-4469-9a90-0ac702567730n%40googlegroups.com > > <https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.google.com%2Fd%2Fmsgid%2Fprojectchrono%2F0346f694-3438-4469-9a90-0ac702567730n%2540googlegroups.com%3Futm_medium%3Demail%26utm_source%3Dfooter&data=05%7C01%7Calessandro.tasora%40unipr.it%7C5bad7925c1e348beaba608da7f5999d4%7Cbb064bc5b7a841ecbabed7beb3faeb1c%7C0%7C0%7C637962320063475420%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=XE%2Flw5LimnmSwp0IDXwtcfmQyuWVbrweLYnFXWlcMvU%3D&reserved=0> > . > > > Firma il tuo 5xmille all’Università di Parma, aiutaci a essere sempre più > accoglienti e inclusivi verso le nostre studentesse e i nostri studenti - > Indica 00308780345 nella tua denuncia dei redditi. > -- You received this message because you are subscribed to the Google Groups "ProjectChrono" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/projectchrono/15925b76-b712-4b51-bd0b-52df5367ebe1n%40googlegroups.com.
