Determination of wear and tear of robotic gripper fingers

Typically: "How do I... ", "How can I... " questions
Post Reply
Ark27
Posts: 9
Joined: 07 Jun 2020, 12:19

Determination of wear and tear of robotic gripper fingers

Post by Ark27 »

Hi,
I am trying to analyze the performance of a robotic gripper finger by carrying out a series of pick and place task. The object is a cube imported and placed on the table which is picked and placed by a gripper.
During the simulation, I noticed that as the cube's position is gradually moving backwards.
For instance the initial x=0.3302 ;y =0.7170 after running the simulation for an hour I notice the objects position in x and y has changed to x=0.3202 ;y =0.7162. The simulation is ran at dt=50.0 ms, ppf 1 and physics engine as Vortex.
Can you kindly explain why I am noticing this please? and measures to minimize this.

Also, the main reason for me to be testing this is to determine the failure of the gripper.
How can I do this? What are the parameters that are required to me configured to determine an approx. wear and tear of the gripper?

Is modeling this a possibility using Coppelia Sim?

coppelia
Site Admin
Posts: 10339
Joined: 14 Dec 2012, 00:25

Re: Determination of wear and tear of robotic gripper fingers

Post by coppelia »

Hello,

the way a particular physics engine operates can greatly vary, and there is only little that can be seen/understood as an outside user, from what is going on in details internally (type of calculation models, approximations, etc.). Additionally, there are usually many many parameters and settings that can influence a dynamic simulation.

If yoou do not stop/restart a simulation, and keep simulating the same thing in a loop, then it appears very normal to me that there will be small errors grinding up. You can either start/stop a simulation for each grasping task, or you can programmatically reset the cube to its initial position after each grasp.

Wear and tear is a very difficult topic with an ordinary physics engine, since it will do high-level approximations at many levels, in particular with contacts, and there is often only little correspondence with reality (e.g. in reality each material has compliance and there are dozens/hundreds of contact points/surfaces between contacting objects).

Cheers

Ark27
Posts: 9
Joined: 07 Jun 2020, 12:19

Re: Determination of wear and tear of robotic gripper fingers

Post by Ark27 »

Perfect, Thanks for your reply. In your opinion is any of the physics engine in CoppeliaSim can help of which wear and tear? Or at the moment, is this a limitation.

Also, I was trying to set this parameter,

Code: Select all

sim.setEngineBoolParam(sim.vortex_global_multithreading,-1,True)
print(sim.getEngineBoolParam(sim.vortex_global_multithreading,-1))
The result prints false.

Can you please let me know what I have done wrong? How do i set multithreading to true?
Thanks in advance for your time!!

coppelia
Site Admin
Posts: 10339
Joined: 14 Dec 2012, 00:25

Re: Determination of wear and tear of robotic gripper fingers

Post by coppelia »

There are 2 reasons for that:
  • in Lua, True does not exist. Try with true
  • you can only set the global engine properties if you the configuration mode is custom.
Cheers

Post Reply