3D Robotics

AttoPilot review, Part 2: The software

AttoPilot comes with two desktop programs, a full-featured ground station and a basic KML-to-TXT converter. Before I get into the specifics, I'll give some quick impressions. The Ground Station is intended to be used while the aircraft is in the air or to replay a saved flight file. It can display real-time telemetry data if you have a radio modem hooked up to AttoPilot, and can send commands back to AttoPilot if that radio modem is 2-way. It's a nicely done professional piece of software and seems to cover all the bases. Two thumbs up. The KML-to-TXT converter is a bit of a kludge, compensating for the fact that AttoPilot doesn't have a native way to input waypoints. Instead, it recommends using Google Earth Plus to point-and-click waypoints, exporting them as a KML file that the supplied utility can covert into a form that AttoPilot can use. Unfortunately, this process, which is pretty cumbersome at the best of times, is now also impossible, since Google has stopped selling Google Earth Plus. I've asked Dean for advice on what people should do about that, but haven't heard back yet. [UPDATE: Dean says that the free Google Earth 5 now includes the KML export feature. So ignore the Google Earth Plus reference in AttoPilot instructions, which I assume will soon be updated] There is also, to my mind, a missing piece of software, which is a setup utility. In the absence of that, the main way you adjust AttoPilot for your plane is by editing a text file that is stored on the on-board SD card. That file is pretty scary looking (and we should know, since we currently make people do something similar with ArduPilot, although we'll be releasing a setup utility that avoids that soon), and consists of hundreds of lines that look like this:

I assume that in later versions of AttoPilot, there will be some program that helps you enter those values. In the meantime, however, it's a relatively daunting process of trial-and-error, reading the manual and tweaking a supplied generic file. I haven't flown a plane with it yet, so I don't know how well the generic file will work for my target platform, an EasyGliderPro, but I'll update this as I learn more. For the rest of the review,. I'm going to focus mostly on the Ground Station software, which is the most polished part of the package. Here's the main screen, showing the playback of a flight:

The menu items give you the following dialog boxes. Settings:

When you click "Read from AttoPilot", the following boxes are added to the interface:

If you have a 2-way radio modem, those boxes allow you to send in-flight commands to AttoPilot. These are the available commands:

If you click on "Show PID", you get a new window that creates graphs of key values over time:

The "KML Utilities" launch the aforementioned KML-to-TXT file converter. You can convert both ways:

All in all, an impressive piece of software. My hope is that in the next version of AttoPilot, the waypoint entry and setup process will display an equal level of polish.
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  • Dean,
    Is an Attopilot for helicpoters in the works?
  • 3D Robotics
    "Add path", then right click on the path and save as KML.
  • How exactly do you add waypoints by point and click in Google Earth? I've been looking around and can't find how to do it. I must be missing something. I've got the latest free version (5.0). Also, where's the menu to export to kml file?


  • 3D Robotics
    Huge apologies on the "Dead" thing.. Overeager spellchecker in my browser! Now corrected...
  • 3D Robotics
    Just a point of clarification on the SET. Dean is absolutely right that there are only 106 parameters. But I was referring to the lines in the document, of which there are indeed more than 300 (many of which are instructional comments, between and below parameters).

    I wouldn't be surprised if Dean makes available custom SET files for common airframe in the future, which will help avoid people having to mess with this file too much.

    FWIW, that's what we're doing with ArduPilot 2.2. We have a setup utility, and it will let you load airframe files. That's what Paparazzi does, too.
  • Moderator
    Why the non standard instrument layout Dean??

    Bit weird if your into flying
  • "Dead is absolutely right.... I wouldn't be surprised if Dead makes ..."

    I'm not Dead! I am fully alive.
  • T3
    You have defenitely come up with the best (and only) commercial autopilot in this price range!

    Oh, and although you have probably already figured this out:You can load a 'network' link to google and point that to a local file. You can also set that network link to be updated periodically so by updating that local file (.kml) constantly you get that moving plane in GoogleEarth rather neatly. ArduSim uses this...
  • T3

    Very impressive start. I will now wait for my birthday or for my wife to be looking the other way so I can get a new toy.....
  • The "PID" window shows 5 key processes for stabilization and navigation. In the non-RC modes you can immediately (and intuitively) gauge if the PID gains are too high, too low, or just about right. I'll soon publish a set of narrated videos of example flights with poor tuning and good tuning.

    Regarding there being "hundreds" of lines in SET, it is 106 to be exact. Of those, 3 relate to elevon mixing setup, 7 for servo reversing, about 40 for loiter duration and radius choices and payload management for triggers, and related items. Now we are down to 56 left to explain. For stabilization there are 7 P and 7 D gains (I gain is set automatically based on P, and the Ki reset times are hard coded into Atto). Of the remaining 42 (or so) SET values, they have to do with navigation tuning. Yes, navigation has its own PI and D type gains, max rates, max pitch and roll angles, and widths of proportional bands. To allow Atto to fly things from 8 ounce MAVs up to 30+ pound UAVs all of these parameters need to be accesible to the end user. Each item in SET was added based on extensive testing and a demonstrated requirement to make flight even more robust.

    >> The generic SET file on Chris's SD card has very good navigation gains for normal RC craft<<

    90% of the stabilization gain tuning is no more daunting than simple P gain for pitch and roll response, not much different than tuning for an FMA CoPilot. After P gains are decent, add a smidge of D gain to further reduce overshoot and dampen oscillation.

    There are also about 6 parameters related to failsafes for mAh cutoff of battery, and a distance greater than which Atto 100% locks out the RC Tx until certain conditions are satisfied. You also have exponential gains on pitch and roll.

    So, this is how you get to 106 parameters. About 12 of them relate to getting good flight performance, and 94 of them relate to everything else plus flight safety margin and payload management. It has been about 1 year since I relaized "Oh crap, stable autonomous flight is BORING... I need to start workking on payload management, better and unique navigation, and failsafes".
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