Jyotirmoy, The reported “tire force” is the force/moment that are applied to the wheel spindle as result of the tire/terrain interaction. It is neither the motion resistance (look at the direction of the Fx component) nor the drawbar pull. You should be able to work out the motion resistance from this. As for drawbar pull, that could be obtained as the reaction force in the linear actuator that imposes the specified rig longitudinal speed (assuming you set a given longitudinal speed and given wheel angular speed, hence a given longitudinal slip value, that would give you one point on the slip-DBP curve). I believe there is no accessor method to return that reaction force. I’ll add it.
--Radu From: [email protected] <[email protected]> On Behalf Of Jyotirmoy Mukherjee Sent: Friday, April 7, 2023 2:59 PM To: ProjectChrono <[email protected]> Subject: Re: [chrono] Query regarding creating tire file in Chrono Hello Dr. Negrut and Dr. Serban, Thank you for the reply. I would like to clarify somethning about the tire forces. I'm using the function ReportTireForces() in the ChTireTestRig class, auto Force_out = rig.ReportTireForces(), the Force_out.force.x() is the Fx force. Could you please let me know if this force is the motion resistance or drawbar pull? I wanted to make sure that I am printing out the right Force. Also, is there any specific variable that gives the motion resistance/drawbar pull separately? Thank you in advance. Sincerely, Jyotirmoy On Friday, March 31, 2023 at 1:13:34 PM UTC-4 Radu Serban wrote: Ekansh, Both Dan and I already answered these questions. See the other thread with my reply to Jyotirmoy’s post. --Radu From: [email protected] <[email protected]> On Behalf Of Ekansh Chaturvedi Sent: Wednesday, March 29, 2023 1:57 PM To: ProjectChrono <[email protected]> Subject: Re: [chrono] Query regarding creating tire file in Chrono Thanks for your email Dr. Negrut. I really appreciate it. I am trying to set up a passenger car tire and test it on the sandy loam terrain. I am using ChTeameasy class to make a tire file where we can input inflation pressure. There it asks for two values namely Inflation Pressure design and Inflation pressure use. To make the tire file, I copied an existing passenger car tire file (sedan), erased all the data except the mass, inertia and tire's dimensional data, and included "Inflation Pressure design [Pa]" and "Inflation Pressure use [Pa]" , as per the online documentation. When I simulated the same on the rigid terrain, with different values of inflation pressures, I got descent results in terms of Fx, Fy and Fz (using ReportTireForces). However, when I am trying to simulate on the sandy loam terrain (using SetTerrainSCM), I am getting exactly same values that I got with rigid terrain, which doesn't make sense. Further, changing inflation pressures with soil terrain does not change the output results and I see no deformation in soil terrain mesh (which is clearly visible when I run the demo file). Since I copied the exact line of code for setting soil terrain from a demo file, I am not sure if the problem in the tire file or I am missing something while setting the terrain. I am unable to figure out where the problem lies. Please share your thoughts on the same. My apologies for a lengthy email. I really appreciate your help. Have a great day! Sincerely Ekansh On Tuesday, March 28, 2023 at 10:59:05 PM UTC-4 Dan Negrut wrote: Hi Ekansh, Can you spell out, step by step, how you went about implementing your solution? How do you envision the flow of the work process, its steps? Not the gory details, but high level approach. Also, what type of tires do you plan to model? On-road or off-road? Of the tire models available in Chrono, what model[s] do you plan to use? 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<tel:(608)%20772-0914> http://sbel.wisc.edu/ http://projectchrono.org/ --------------------------------------------- From: [email protected] <[email protected]> On Behalf Of Ekansh Chaturvedi Sent: Tuesday, March 28, 2023 3:23 PM To: ProjectChrono <[email protected]> Subject: [chrono] Query regarding creating tire file in Chrono Hi, Hope this email finds you well. We are using Chrono to conduct an on-rig analysis of different tires and we are pretty new to using Chrono. We are stuck while trying to create a custom tire file that takes tire inflation pressure in units of pressure, along with the other structural dimensions, as an input . It's been a month and we are still trying to figure that out. We have realized that we cannot waste time anymore on trying ourselves as the deadlines are coming close, and we need help. We would really appreciate it if you could help us out with this through a zoom meeting. Please share your availability and feel free to let us know if you have any questions or concerns. Thanks and regards, Sincerely, Ekansh Chaturvedi Graduate Student, Terramechanics, Multibody and Vehicle Systems Laboratory (TMVS), Computational Sciences Laboratory (CSL), Department of Mechanical Engineering Virginia Tech -- 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]. 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