Flowdeck-Functionality

Firmware/software/electronics/mechanics
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tungnx94
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Joined: Wed Dec 27, 2017 11:49 am

Flowdeck-Functionality

Post by tungnx94 »

Hello,

we are working on a project. Our goal is to build a small autonomous hovering system using the flow deck. To do this we need to understand the impact of flow deck on the original system. What extra information does it deliver that made hovering possible ? And where is this information saved (as variable) ?

Many thanks in advance.
arnaud
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Re: Flowdeck-Functionality

Post by arnaud »

The flow deck contains a ranging sensor that outputs the distance to the floor (or whatever is directly under the sensor) and an optical flow sensor that output delta X/delta Y in unit-less ticks (we assume they are movement in pixel on the the optical sensor).

These data allows the Kalman filter to calculate an accurate estimation of the absolute height and horizontal velocity, assuming the Crazyflie is flying over a flat floor. Without the flow deck these estimation would be drifting since the Crazyflie would be relying only on IMU.

The raw data and estimations are available as log variable. I have already posted a couple of screenshoot of what the raw data from the flow sensor looks like: viewtopic.php?f=6&t=2828&p=14082#p14082 and viewtopic.php?f=2&t=2882&p=14533#p14393
tungnx94
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Re: Flowdeck-Functionality

Post by tungnx94 »

I suppose the distance to the floor is saved in the ranging log variables ? Here are 8 distances and 8 pressures values measured.
arnaud
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Re: Flowdeck-Functionality

Post by arnaud »

The distance to the floor is available in the "range.zrange" log variable.

I am not sure what you mean about 8 ranges and 8 pressures, the flow deck has 1 ranging sensor that outputs 1 range measurement. In a recent firmware, the 'range' log group will have more variables to accommodate the multiranger deck that has ranging sensors in 5 more directions.
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