How do robots milk cows? (V0132)
Jenny Jago explains how the milking process works in an automatic milking system. The robot needs to be able to cope with differences in individual cows and solve problems which may occur during the milking process.
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There are two problems which a robotic milker has to deal with while milking: each cow is unique, and each time she comes for milking her teats will be in slightly different positions. The robot must be able to cope with these differences and adapt to each situation without wasting time. Jenny Jago explains how this works.
Dr Jenny Jago (DairyNZ): When a cow arrives at the waiting yard, the gate to the automatic milker or the robotic milker is opened. At that point she can walk into the bale, sometimes we call it a crate, and the aerial picks up the ID of that cow, and then at that point the robot knows for example that its cow number 15. It has a memory of where that particular cow’s udder and teats should be. So the arm swings in to underneath the cow near her udder, and then first of all it washes her teats. So there are little rollers it goes through, which wash each teat to make sure it’s clean, and then there is a laser which starts to look for the teats. So it has a broad idea of where to go through its memory of where that cow’s udder and teats were last time she came in to be milked, but then it uses a little laser to identify where the teats are at this particular milking, and then it puts the cups on one teat at a time.
The cow has obviously got four teats there on the udder, and it starts out at the back and puts two back cups on separately. Then it puts the front cups on and then the cow milks. Now if there is a problem, for example if it doesn’t get the cup on the teat, or the teat folds over and maybe it misses and gets in on the udder, it will after a period of time detect that there is not milk flowing in the tubes. So therefore it assumes, “Well, I haven’t got it on the teat and so I need to have another go.” So it pulls that cup off, moves it and tries to pop it on the teat.
Once there is milk flow detected in all four quarters, the cow milks successfully and then what happens, once the milk flow starts to decline, once it gets to a certain level, it will take the cup off. So it takes the cup off each quarter separately. Sometimes you can just have three cups have come off, those quarters have finished, but you’ve still got the left front quarter still going. And when all the quarters are finished it takes that last cup off, and then it applies a teat spray to the teats - it’s a sanitiser. And then the gate opens and the cow walks out, and then the entry gate opens for the next cow to come in.
- 01 March 2006
- The University of Waikato