Hello Harry, Your simulation results looks great and are similar to what I hope to implement in my setup. I am interested in discussing more about this and would love to set up a meeting as soon as possible. Can you please let me know what day/time you are available?
Best regards, Nnamdi On Wednesday, July 30, 2025 at 1:50:56 PM UTC-4 [email protected] wrote: > Picture attachment for last message: > [image: Screenshot from 2025-07-30 10-45-41.png] > Best, > Harry > On Wednesday, July 30, 2025 at 11:17:42 AM UTC-5 Harry ZHANG wrote: > >> Hello Nnamdi, >> >> My name's Harry and Dan asked me to follow up on this thread. >> >> About couple weeks ago, we start exploring using PyChrono as our physics >> engine to train RL policies for quadruped locomotion task. Our projects's >> goal is to investigate simulation terrain's effect on locomotion policy >> performance. In PyChrono there are different fidelity levels for terrain >> model (from low to high): rigid terrain (rtf<<1) --> SCM deformable terrain >> (rtf~=1)-->CRM granular terrain(rtf~=5), where rtf means real time fator. >> RL library we are using is "RSL-RL". >> >> Please check this link for prelim results we got: >> https://drive.google.com/drive/folders/1Yhx1goYDsv0FZdk4OfyH9_yRazkRSwMQ?usp=sharing. >> >> The locomotion policy trained for 0.5 m/s longitudinal speed walking. The >> policy trained with rigid terrain (about 6 hours) and we put it on scm >> deformable terrain for testing purpose, in both rigid and deformable >> terrain the evaluation looks decent. >> >> For us, there are two major things in our todo list: 1) implement some >> parallelzation methods during training. current 6 hour training time is >> trained with one single simulation agent interact with RSL-RL algorithm, we >> try to see if it's possible to do faster by training with multiple >> simulation agents. 2) Include quadrupeds with CRM terrain in both policy >> training and evaluation. See the attched picture, we have a simulation >> script includes quadrupeds on CRM terrain, but we need to merge this into >> RL pipeline. >> >> Let me know if you have any questions, I am available for meeting if you >> want me explain more about the pipeline and details. >> >> Best, >> Harry >> >> On Monday, July 28, 2025 at 4:40:48 PM UTC-5 [email protected] wrote: >> >>> Thank you so much for your response. >>> >>> We are starting to work in this area as well, from a slightly different >>> perspective. Harry, a great student in the lab, will share his findings in >>> about a week, to steer you in the right direction. Are you working with a >>> quadruped or something similar? >>> >>> I am working on a small-sized bioinspired quadruped robot, and I look >>> forward to the findings from your student. >>> >>> Is it like (a) the entire terrain is made up of rocks 2cm to 6 cm, or >>> (b) you have some deformable terrain that once in a while has some rocks 2 >>> cm to 6 cm scattered around? This is important, since (a) will likely take >>> more time to run than (b). >>> >>> I am interested in having the entire terrain composed of movable rocks, >>> which the limbs can interact with, such as each terrain box filled with >>> rocks of a specific size (2cm to 6cm). I am also open to suggestions on >>> whether this setup might be computationally intensive and any alternatives, >>> such as option B. The image below is what I have in mind (generated in >>> MuJoCo, but is fixed to the ground) >>> [image: Screenshot 2025-07-28 172945.png] >>> >>> In principle, this should be doable but we haven’t tried it yet. The >>> needed modeling elements are in Chrono, it’s just a matter of putting a >>> model like this together and seeing how it does. Easier said than done, but >>> we might be able to provide some feedback when you cross that bridge. >>> >>> Thank you. I will provide more details on my proposed implementation >>> soon. >>> >>> In about one week we’ll share a way to install a newer version of >>> PyChrono, a beta version, that has support for what’s called in Chrono “the >>> CRM terrain” model. Might be helpful for you. Needs an NVIDIA GPU to run. >>> >>> Looking forward to the new version. I have been facing some SDL2 package >>> errors with my current version. I gave more details in a different thread. >>> On Thursday, July 24, 2025 at 3:53:14 PM UTC-4 Dan Negrut wrote: >>> >>>> Please see my comments in this font below. >>>> >>>> >>>> >>>> Thank you, >>>> >>>> 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 <(608)%20772-0914> >>>> >>>> http://sbel.wisc.edu/ >>>> >>>> http://projectchrono.org/ >>>> >>>> --------------------------------------------- >>>> >>>> >>>> >>>> *From:* Nnamdi Chikere <[email protected]> >>>> *Sent:* Thursday, July 24, 2025 10:31 AM >>>> *To:* Dan Negrut <[email protected]> >>>> *Cc:* ProjectChrono <[email protected]> >>>> *Subject:* Re: [chrono] Help with Granular Simulation on Windows using >>>> PyChrono >>>> >>>> >>>> >>>> Hello Professor, >>>> >>>> >>>> >>>> Thank you so much for your reply. >>>> >>>> >>>> >>>> For the first stage, I am trying to optimize the parameters for control >>>> of the robot’s locomotion on complex environments including sand and rocks >>>> using CPGs. The end goal is to later use RL to implement adaptive control >>>> with changing terrains. >>>> >>>> We are starting to work in this area as well, from a slightly different >>>> perspective. Harry, a great student in the lab, will share his findings in >>>> about a week, to steer you in the right direction. Are you working with a >>>> quadruped or something similar? >>>> >>>> >>>> >>>> For the rock sizes, I was looking to implement three rock sizes ranging >>>> between 2cm and 6cm filled in a box on which the robot will operate. >>>> >>>> Is it like (a) the entire terrain is made up of rocks 2cm to 6 cm; or >>>> (b) you have some deformable terrain that once in a while has some rocks 2 >>>> cm to 6 cm scattered around? This is important, since (a) will likely take >>>> more time to run than (b). >>>> >>>> >>>> >>>> I am also trying to implement a flexible limb that will be attached to >>>> the motors and deform when in contact with some force or the ground, is it >>>> possible to implement this to a specified link? >>>> >>>> In principle, this should be doable but we haven’t tried it yet. The >>>> needed modeling elements are in Chrono, it’s just a matter of putting a >>>> model like this together and seeing how it does. Easier said than done, >>>> but >>>> we might be able to provide some feedback when you cross that bridge. >>>> >>>> >>>> >>>> I am working with Python and windows, and would appreciate some help as >>>> regards this >>>> >>>> In about one week we’ll share a way to install a newer version of >>>> PyChrono, a beta version, that has support for what’s called in Chrono >>>> “the >>>> CRM terrain” model. Might be helpful for you. Needs an NVIDIA GPU to run. >>>> >>>> >>>> >>>> Best regards, >>>> >>>> Nnamdi >>>> >>>> >>>> >>>> On Thu, Jul 24, 2025 at 2:10 AM Dan Negrut <[email protected]> wrote: >>>> >>>> If you describe what you need to do with your robot, we might be able >>>> to steer you in the right direction. >>>> How big are the rocks you mentioned? >>>> >>>> What sort of end-goal do you have? Design of robot, control of robot, >>>> RL, optimal design, etc. >>>> >>>> >>>> >>>> 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 >>>> <https://urldefense.com/v3/__https:/www.google.com/maps/search/1513*University*Avenue**A0D*0A*Madison,*WI*53706-1572?entry=gmail&source=g__;KysrJSUrKys!!Mak6IKo!Od8BEUkPpm5WoEens9KtQIg47iogD1i2m9LDYGHeEv2M8GiWuVl9N0Stk5HjyF-DIbSFX75lMxV4hhD5$> >>>> >>>> Madison, WI 53706-1572 >>>> <https://urldefense.com/v3/__https:/www.google.com/maps/search/1513*University*Avenue**A0D*0A*Madison,*WI*53706-1572?entry=gmail&source=g__;KysrJSUrKys!!Mak6IKo!Od8BEUkPpm5WoEens9KtQIg47iogD1i2m9LDYGHeEv2M8GiWuVl9N0Stk5HjyF-DIbSFX75lMxV4hhD5$> >>>> >>>> 608 772 0914 <(608)%20772-0914> >>>> >>>> http://sbel.wisc.edu/ >>>> >>>> http://projectchrono.org/ >>>> <https://urldefense.com/v3/__http:/projectchrono.org/__;!!Mak6IKo!Od8BEUkPpm5WoEens9KtQIg47iogD1i2m9LDYGHeEv2M8GiWuVl9N0Stk5HjyF-DIbSFX75lM0FtMmwz$> >>>> >>>> >>>> --------------------------------------------- >>>> >>>> >>>> >>>> *From:* 'Nnamdi Chikere' via ProjectChrono <[email protected]> >>>> >>>> *Sent:* Tuesday, July 22, 2025 6:16 PM >>>> *To:* ProjectChrono <[email protected]> >>>> *Subject:* [chrono] Help with Granular Simulation on Windows using >>>> PyChrono >>>> >>>> >>>> >>>> Hello. >>>> >>>> I am working on a simulation where a robot moves on different terrains, >>>> and I want to simulate the robot moving on sand and rocks. I have been >>>> able >>>> to implement the soil terrain using the SCM parameters in PyChrono. Is it >>>> possible to implement granular media, such as rocks, in PyChrono? I >>>> attempted to install the DEME package, but encountered several errors. I >>>> am >>>> working with PyChrono 9.0 and Python 3.9. >>>> >>>> Thank you. >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "ProjectChrono" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To view this discussion visit >>>> https://groups.google.com/d/msgid/projectchrono/d38be8a1-f6e0-4661-83ba-d51b500ccea5n%40googlegroups.com >>>> >>>> <https://urldefense.com/v3/__https:/groups.google.com/d/msgid/projectchrono/d38be8a1-f6e0-4661-83ba-d51b500ccea5n*40googlegroups.com?utm_medium=email&utm_source=footer__;JQ!!Mak6IKo!IHl25Nn94rVvk-8cbLYWCsyZEpu7zcoKd_JY1u7_ZFpAebs2_ga8vymx9iyQT1Ywjzy8INBVzHAHobmHZEkRFozUi6s$> >>>> . >>>> >>>> -- 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/9a003ce3-85f0-463b-aa72-108683d7d043n%40googlegroups.com.
