One of the main things I am working on for Austria is improving the responsiveness of the walk engine george and I wrote so that we can react quicker to changes in the balls location, etc. On the four legged Aibos, we could stop nearly instantly – on the Nao, we need to look ahead at our future plans a certain amount so that we can be ready to follow them when the time comes. The following is a graph of how our center of mass trajectory is affected during walking when we lower how far into the future we preview. As the preview period gets lowered, the curves become less and less ideal. The Cyan curves are the ones with the longest preview period:preview-period
2 thoughts on “Controller preview graph”
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Yeah, that was sloppy on my part — the preview length is in 20ms increments, so N=60 is 60*20ms = 1.2 seconds of look ahead at future plans.
The roughly square curves are the desired output of the system, with black being the ideal, and the colored square curves are how close the sinusoidal curve of the same color came to realising the desired output. The sinusoidal curves are the center of mass trajectory, and the square curves are the desired ZMP curves (i.e. the desired balance of the robot)
There should be labels on the graph itself. What are the lengths of the preview periods? What are the sinusoidal curves?