Hi Rainer – please keep in mind that Jay is using the SCM terrain. Handling tire models, which carry no collision geometry, will not work with that terrain.
Jay – you cannot simply increase the step size to whatever you want from purely performance reasons. You must use a step size small enough to ensure a stable. You may want to experiment with other integration and solver types in Chrono. --Radu From: [email protected] <[email protected]> On Behalf Of [email protected] Sent: Friday, March 8, 2024 7:58 AM To: ProjectChrono <[email protected]> Subject: [chrono] Re: Json File Jay, you are on the right way with reducing the step width. You should also use a newer version of chrono, version 8.0 is quite out of date, better build your own one from the actual repository. If you must use rigid tires, a step width of 0.002 secs can be to big. For vehicle simulation it is generally better to use handling tire models (PacejkaXX, TMeasy or TMsimple). Using TMeasy or TMsimple you can let chrono 'guess' consistant tire parameters. Be sure to supply realistic values for mass and inertia. With a known tire mass the inertias can be estimated. Try this website https://bndtechsource.wixsite.com/home/rotational-inertia-calculator<https://urldefense.com/v3/__https:/bndtechsource.wixsite.com/home/rotational-inertia-calculator__;!!Mak6IKo!Pbo_NgAilgSOFlQ6hltkBOAbO1_Ku8FkZd9VZV0-jQYH7Sv8-WFAXbewsY6pjoDxgipnqeK1lYRr9ymYwNaQNKg$> Generally the time step for vehicle simulations should not increase 0.001 secs. Rainer [email protected]<mailto:[email protected]> schrieb am Freitag, 8. März 2024 um 06:49:20 UTC+1: Rainer, Maybe I found the reason for this problem, I changed the size of step_time, different sizes of step_time have different stability of the car (see the video link: https://youtu.be/g3iQKZTntdM<https://urldefense.com/v3/__https:/youtu.be/g3iQKZTntdM__;!!Mak6IKo!Pbo_NgAilgSOFlQ6hltkBOAbO1_Ku8FkZd9VZV0-jQYH7Sv8-WFAXbewsY6pjoDxgipnqeK1lYRr9ymYYgLwQ8I$>). But I am running the algorithm of deep reinforcement learning, I need to improve the training speed to reduce the training time, is there any other way to shorten the simulation time? Looking forward to your reply! Thank you very much Jay 在2024年3月8日星期五 UTC+8 10:53:40<Jay Sun> 写道： Rainer, Thank you very much for your reply! * chrono version: win-64/pychrono-8.0.0-py39_0.tar.bz<https://urldefense.com/v3/__http:/pychrono-8.0.0-py39_0.tar.bz__;!!Mak6IKo!Pbo_NgAilgSOFlQ6hltkBOAbO1_Ku8FkZd9VZV0-jQYH7Sv8-WFAXbewsY6pjoDxgipnqeK1lYRr9ymYRmz1QSk$>2 * tire model, tire format, wheel, vehicle: see the attachment. The "Suspension Input File"and "Brake Input File" in a json file is an official file that I did not modify. (Refer to the rigid tire of Hmmwv, I defined myself) Because of this（https://groups.google.com/g/projectchrono/c/tSPC4GYfBKE<https://urldefense.com/v3/__https:/groups.google.com/g/projectchrono/c/tSPC4GYfBKE__;!!Mak6IKo!Pbo_NgAilgSOFlQ6hltkBOAbO1_Ku8FkZd9VZV0-jQYH7Sv8-WFAXbewsY6pjoDxgipnqeK1lYRr9ymYSfZekTE$>） Jay 在2024年3月8日星期五 UTC+8 03:09:59<[email protected]<mailto:[email protected]>> 写道： Hi Jay, can you give us some mor information: * which chrono version do you use * which tire model ? * tire mass and inertia? * tire format * wheel load Best Rainer [email protected]<mailto:[email protected]> schrieb am Donnerstag, 7. März 2024 um 12:51:26 UTC+1: Hi everyone, I configured this car using a json file, and found that it kept jittering after importing instead of stopping when it hit the ground. Could you please tell me the reason? video link:https://youtu.be/d4ZjRxax0Uw<https://urldefense.com/v3/__https:/youtu.be/d4ZjRxax0Uw__;!!Mak6IKo!Pbo_NgAilgSOFlQ6hltkBOAbO1_Ku8FkZd9VZV0-jQYH7Sv8-WFAXbewsY6pjoDxgipnqeK1lYRr9ymYcC0cMYY$> Regard, Jay -- You received this message because you are subscribed to the Google Groups "ProjectChrono" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<mailto:[email protected]>. To view this discussion on the web visit https://groups.google.com/d/msgid/projectchrono/1840354e-b305-4339-bbb5-8c2807bb2072n%40googlegroups.com<https://urldefense.com/v3/__https:/groups.google.com/d/msgid/projectchrono/1840354e-b305-4339-bbb5-8c2807bb2072n*40googlegroups.com?utm_medium=email&utm_source=footer__;JQ!!Mak6IKo!Pbo_NgAilgSOFlQ6hltkBOAbO1_Ku8FkZd9VZV0-jQYH7Sv8-WFAXbewsY6pjoDxgipnqeK1lYRr9ymYlmvomw4$>. -- 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/PH0PR06MB8237D313B90AF514FFA6FE79A7272%40PH0PR06MB8237.namprd06.prod.outlook.com.
