ePuck: why do they move by default?

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sfranchi

ePuck: why do they move by default?

Post by sfranchi » 15 Feb 2015, 20:26

I am just starting with V-Rep and I am playing with a very simple scene containing a few lights and a few ePucks.
I do not understand why the ePuck model moves forward by default. I tried erasing all the default scripts the ePuck model comes with (there are 4: in the EPuck itself, bodyElement#0, lightSensor, and speaker), but the ePuck still moves forward. Which controller makes it move?

Help appreciated,

Stefano

coppelia
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Posts: 6736
Joined: 14 Dec 2012, 00:25

Re: ePuck: why do they move by default?

Post by coppelia » 15 Feb 2015, 20:46

Hello Stefano,

this is because the two wheel joints of the ePuck has a target velocity different from zero. In the joint dynamic properties, you can set Target velocity to zero. Then the robot won't move anymore.

The child scripts attached to the ePuck simply manipulates that parameter via the API simSetJointTargetVelocity.

Cheers

sfranchi

Re: ePuck: why do they move by default?

Post by sfranchi » 15 Feb 2015, 23:34

coppelia wrote:Hello Stefano,

this is because the two wheel joints of the ePuck has a target velocity different from zero. In the joint dynamic properties, you can set Target velocity to zero. Then the robot won't move anymore.

The child scripts attached to the ePuck simply manipulates that parameter via the API simSetJointTargetVelocity.

Cheers

Thanks! All clear now. Coming to V-Rep from Webots, I am still wrapping my head around the different approach.


Cheers,

Stefano

faroub
Posts: 2
Joined: 26 Jan 2014, 12:22

Re: ePuck: why do they move by default?

Post by faroub » 07 Aug 2018, 15:48

Hallo coppelia team,

I did change Target velocity to zero but the Epuck is still moving (turning slowly on the spot) and this happens only with the animation engine bullet 2.78.

Best,

Farid

coppelia
Site Admin
Posts: 6736
Joined: 14 Dec 2012, 00:25

Re: ePuck: why do they move by default?

Post by coppelia » 07 Aug 2018, 19:47

Hello,

You can improve that behaviour by increasing the inertia and mass of the wheels (e.g. inertia x 64, mass x 4). This is directly related to design considerations 7 & 8, from here.

Cheers

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