simulation Dynamics explained better

Typically: "How do I... ", "How can I... " questions
Post Reply
luberdis
Posts: 6
Joined: 14 Dec 2018, 16:06

simulation Dynamics explained better

Post by luberdis » 05 Jan 2019, 00:58

Hi I have a problem with vrep. I try to simulate a differential robot that drives to a specific point of the surface. The algorithm I use is very common and it is described in this book at page 94 on book at this link I have here

https://www.dropbox.com/s/mr7euyfyhatc9 ... .pdf?dl=0

I implement the code in Matlab and it works pretty fine and you can see the result and its simulated trajectory Image and here you can see if you want the implemented Matlab code here https://www.dropbox.com/s/pndu60m4qepbh ... ove.m?dl=0

Then I try to use the same code in vrep and I create a script at the simulated model that uses this algorithm. I upload the vrep file to check it if you want
https://www.dropbox.com/s/1yavvph02hdxt ... a.ttt?dl=0

The problem is that even it gets really close to the target area, I think the model slips and it misses the target so it gets into an endless loop
Image

Could you please help me about this physics problem and suggest me something I tried the static as you told me before but it did not move at all. I tried different engines as you wrote to another member but nothing.

I would be really grateful if you share your experience to me

Cheers

coppelia
Site Admin
Posts: 6912
Joined: 14 Dec 2012, 00:25

Re: simulation Dynamics explained better

Post by coppelia » 08 Jan 2019, 15:13

When you use a physics engine, it is extremely rare that you get the same results as the theory tells. The differences are due to the way a physics engine works and how it does its computation and simplifications. Each physics engine can display different behaviours.
In case of a mobile robot, you will always have differences because of (among others) how friction is modeled. Also, if you have badly designed your dynamic elements, then you can see effects such as small vibrations, slipping, etc.

Make sure to carefully read this page, in order to exclude all effects that are linked to a bad design.

Cheers

Post Reply