## e-Puck Robot won't stop in front of obstacle

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robothusiast
Posts: 4
Joined: 12 May 2021, 08:41

### e-Puck Robot won't stop in front of obstacle

Hello everyone,
I'm making a line following algorithm where ePuck Robot can stop in front of the obstacle (also in the end of the line). I managed to make the robot stop, but there's something odd about the robot after that. The robot seems to be drifting away from the wall even though I already set the velocity of the left and right wheel to zero as shown in the image below.

This is the footage of the problem that I encountered : https://drive.google.com/file/d/1dRIbzT ... sp=sharing

I've done some research, I'm guessing there's something I have to do with the proximity sensor, so I try this code (in the if statement where the robot have to be stopped)

Code: Select all

if (robotworking) then
-- do the turning algorithm based on the light sensor
else -- robot working state turned to false, means robot have to stop
velLeft=0
velRight=0
for i=1,8,1 do
sim.setExplicitHandling(proxSens[i],1)
end
sim.handleProximitySensor(sim.getObjectHandle('20cmHighWall25cm'))
end

But it seems to not working as I expected.

My question is, how can I resolve this? I want to manage the robot completely stop in front of the obstacle.

coppelia
Posts: 8583
Joined: 14 Dec 2012, 00:25

### Re: e-Puck Robot won't stop in front of obstacle

Hello,

my best guess is that this is directly linked with the physics engine. Try to switch to another engine, or try to select a more precise dynamics configuration mode.

But the best is probably to slightly increase the mass and inertias of the wheels/body, following the dynamics design considerations 7 and 8.

Cheers

robothusiast
Posts: 4
Joined: 12 May 2021, 08:41

### Re: e-Puck Robot won't stop in front of obstacle

coppelia wrote:
14 May 2021, 08:29
Hello,

my best guess is that this is directly linked with the physics engine. Try to switch to another engine, or try to select a more precise dynamics configuration mode.

But the best is probably to slightly increase the mass and inertias of the wheels/body, following the dynamics design considerations 7 and 8.

Cheers
Hello,

You're right! I already lookup the same answer that you say on this posts https://forum.coppeliarobotics.com/view ... uck#p29424 (Pardon me for asking same question)
But there's another thing I wanted to ask. When I try to switch the engine, my Algorithm won't work the way it supposed to be (I don't know why) so I intended to not to change the engine and keep using Bullet 2.78.
I also try to change the mass & inertias of the wheels according to that post and it work!. So the question is how can I change the inertias using sim.setShapeInertia ? I still don't understand the documentation. Perhaps you could enlight me with an example code.

Thanks!
Last edited by robothusiast on 15 May 2021, 00:36, edited 1 time in total.

coppelia
Posts: 8583
Joined: 14 Dec 2012, 00:25

### Re: e-Puck Robot won't stop in front of obstacle

Just change the inertia via the GUI. That's the easiest, since you only need to do that once.

Cheers

robothusiast
Posts: 4
Joined: 12 May 2021, 08:41

### Re: e-Puck Robot won't stop in front of obstacle

Noted, Thank you so much for helping me out!