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2014-11-21 08:58:18 -0600 asked a question How to include a model in the world after some time delay?

Hi Everyone,

I am working on a multi-agent task which is similar to a ball falling on a sponge. I was planning to run multiple iterations of this simulation, with the ball falling onto the sponge from different heights and angles. For this purpose, I had made a sponge.world file which included both the aforementioned models (using the <include> tag) at specific poses.

However, I was wondering if there was any way to introduce a measured time delay between the spawning of the two objects? (So for instance, the sponge gets spawned first, then there's a delay of 2 seconds, and then the ball gets spawned at the specified pose)

Thanks!!!

2014-11-21 08:47:57 -0600 answered a question Body falls through the object its placed on, if Kp and Kd parameters are varied.

So here's how I did it. I used Andrei's values above to create a layer of thick sponge. Then I added a layer of very thin mud on top of this layer.

This allowed my body to fall more evenly into the sponge, without falling through the surface.

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2014-11-18 09:55:54 -0600 commented question Body falls through the object its placed on, if Kp and Kd parameters are varied.

Ok. Will try this. Should I start with zero Kd?

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2014-11-18 08:35:24 -0600 commented answer Body falls through the object its placed on, if Kp and Kd parameters are varied.

Hi Andrei, I thought the Kp, Kd and <erp>, <cfm> values were related and so I wasn't tweaking those. But will try your values now. Will definitely update the thread.

2014-11-18 08:33:13 -0600 commented question Body falls through the object its placed on, if Kp and Kd parameters are varied.

I've tried a bunch of values, but the ones for which the body falls through are close to: Kp = 50, Kd = 0 (for both bodies). For rigid bodies, Kp = 50000, Kd= 5000.

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2014-11-17 19:21:06 -0600 asked a question Body falls through the object its placed on, if Kp and Kd parameters are varied.

Hi Everyone,

I'm not sure if this is an ODE question and if it belongs on this forum, but please do redirect me to the right forum if this is the wrong place for this question.

I was trying to model the interaction between two soft-bodies in Gazebo using the ODE physics simulator. In a simple sense, my model is like a rubber ball placed on a soft-sponge (rectangular in shape).

I was tweaking the Kp and Kd parameters(which are within the ODE tags) of the SDF files of both objects to see if I was able to get the right interaction. When I kept the Kd values very low, the rubber ball would simply fall through the sponge to hit the ground (the sponge is suspended in air ), however, if the Kd is very high, the sponge behaves like a rigid body. How can I allow the ball to sink into the sponge, and yet not fall through the sponge?

Thanks! :)