Ted – there was no video attached… One thing that might be worth trying is to use SCM deformable terrain. If you have a couple of hours, give it a try – folks in our lab have had good success with that.
Dan --------------------------------------------- Bernard A. and Frances M. Weideman Professor NVIDIA CUDA Fellow Department of Mechanical Engineering Department of Computer Science University of Wisconsin - Madison 4150ME, 1513 University Avenue Madison, WI 53706-1572 608 772 0914 http://sbel.wisc.edu/ http://projectchrono.org/ --------------------------------------------- From: [email protected] <[email protected]> On Behalf Of Ted Sender Sent: Saturday, January 11, 2025 10:32 PM To: ProjectChrono <[email protected]> Subject: [chrono] Tires Rotating Beyond Mechanical Limits Hello, I am currently using Chrono for vehicle simulations with a polaris vehicle. I am using rigid tires on rigid terrain. I am noticing that with certain terrain profiles one or both of the front tires rotate very quickly beyond its mechanical limit when the vehicle drives over a harsh bump/dip. These are the current settings I am using: Solver: Barzilai-Borwein, tolerance 1e-6, max iters 400, time step 1 ms Collision: Bullet, default suggested envelope 1 mm, default suggested margin 1 mm Terrain: Rigid, coeff friction 0.6 I have tried using different solvers, but they did not seem to work (some just failed to perform the calculations or crashed the program). I tried lowering the time step from 1 ms to 0.2 ms, but that did not work either. Attached is a video showing an example of the problem I am having. Right around t = 6 seconds, the front right wheel drives over a dip and then the wheel suddenly rotates clockwise well past its mechanical limit (the limit is about 0.48 radians, but the wheel rotates like 2 radians). I also logged some force/moment values to the terminal to see what was going on, thinking that it could have been a problem with the tire forces. Attached is a .txt file showing the tire's steering angle, tire force and torque values, and the applied force and torque to that wheel's spindle (I believe all forces/moments are expressed in the global frame). >From this data, it seems that when the tire has no reported force/torque, the >spindle still has some applied force/torque. At t = 5.1 seconds, this occurs, >but is not a problem as the spindle torque is rather small. However, at t = >5.90 seconds, the tire force is zero but the spindle torque starts to increase >and then the wheel rotates beyond its limit. Does this seem like a problem with the collision model/settings or is it caused by something else? Any help is greatly appreciated. I hope the data provided is helpful, but if you need some more values, let me know. Thanks, Ted -- 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]<mailto:[email protected]>. To view this discussion visit https://groups.google.com/d/msgid/projectchrono/38e5d8a2-5ccc-47bf-93cb-bb0f6ff6e327n%40googlegroups.com<https://urldefense.com/v3/__https:/groups.google.com/d/msgid/projectchrono/38e5d8a2-5ccc-47bf-93cb-bb0f6ff6e327n*40googlegroups.com?utm_medium=email&utm_source=footer__;JQ!!Mak6IKo!IWB4NaZMiARYuUywzXWMFmkLZzGIyuN5qnFl3Q6IJPyX-E8W4TJaXJwRH3RrQod2PHaq9IZU0O17gy62$>. -- 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 visit https://groups.google.com/d/msgid/projectchrono/DM8PR06MB770363C766D26229471BEF17B11E2%40DM8PR06MB7703.namprd06.prod.outlook.com.
