I need to solve a problem within mechanic of fluids for a part of my thesis. Robot will pick up a bottle of beer, cola, julebrus or any other kind of beverage. And then it has to bring it to the glass and pour it in the glass. But now I came to some problems, because I have to pour only half of the volume in side of the glass, and pouring process will be controlled by robot controller. I have to find out mathematical models that are governing the process of pouring, within this I have to find dependencies between flow from the bottle, angle of the bottle. And with this I will use force sensor to control the pouring process.

Some of the assumptions I made for the beginning:

  1. The flow is laminar and there is no viscosity
  2. Flow will be constant and intake of air will be constant

But later when I started to do the math many problems appeared here. First is the gulping of the air into the bottle neck, in the beginning of the pouring it's a big problem, later when there is smaller volume of fluid in a bottle that's not a problem anymore. And I can't count that my flow will be constant because of the air intake and foam that is constantly forming.

And also because the area from where fluid is going out is changing constantly how can you relate it to the angle of bottle tilt? And before I forget I have to take inertial and gravity compensation in account for this.

  • $\begingroup$ it is a very complex problem involving turbulence, unless you can make the robot to start pouring slow enough at the beginning (but it might not help). My suggestion, is unless your thesis requires to use fluid mechanics, use some easier algorithm based of feedback instead, it will be simpler and closer to what a human do. $\endgroup$ – user16007 Apr 22 '13 at 0:40
  • $\begingroup$ Is the robot working blind, or does it have any kind of sensors? My 4-year-old grandson loves pouring liquids, and he's a long way from caring about laminar inviscid flow, blah, blah... $\endgroup$ – Mike Dunlavey Apr 22 '13 at 0:52
  • $\begingroup$ Speed range of a industrial robot that I'm using is from 0 to 2000 [mm/s], so that's not a problem, but problems with pouring slowly is that to surface tension fluid will flow on the side of the bottle, and if I pour to fast then there will be no possibility to pour it into the glass correctly. I have done some calculations with the pouring process, but as I said experiments and data from force sensor are showing much discrepancies. I need some mathematical formulations that will give me dependence between the flow and angle. And within all of it turbulence and foam are creating much problems. $\endgroup$ – Slavisa Galamic Apr 22 '13 at 4:56
  • $\begingroup$ @Slavisa: My point is, do you have a feedback loop? When I was in grad school 40 years ago, somebody programmed a robot to pour coffee in a cup by using a video camera connected to the computer. It could sense the rising liquid level and stop pouring at the right time. It's not much about physics, it's about heuristics and feedback. $\endgroup$ – Mike Dunlavey Apr 22 '13 at 13:03
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    $\begingroup$ @Christoph B. No, because I'm using an RRR Industrial robot, so in a sense its a 6 DOF robot. I have made some fixtures for the glasses, but those are just for holding and easier positioning of the glasses and bottles. I have limited space so I have to take that also in account while working with this. My main problem now is how to find correlation between angle and the flow that I can use here. And change of volume that is happening in a period of time, because I will have to arrange 1 bottle to 2 glasses. $\endgroup$ – Slavisa Galamic Apr 30 '13 at 11:53

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