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3D Robotics

Harvard developing robot bees

Posted by Chris Anderson on October 20, 2009 at 9:16pm

From BotJunkie: "The National Science Foundation is giving Harvard a cool $10 million to develop a robot bee colony. That’s right, not just one, but an entire colony of robot bees. The bees will buzz around on flapping wings, use optical flow sensors for navigation and obstacle avoidance, sport cute little antennae as well as “pollination and docking appendages,” and use an as yet unspecified power source." We have got to get an optical flow community building here. All it takes is an old optical mouse to get started, as we discussed here!
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Paparazzi help!

Posted by Jesus on October 20, 2009 at 3:00pm
Hello!!I´m very interested in the paparazzi uav ans the booz (quadcopter). But I have some questions that I wish that anybody could answer it.1st- It´s possible to use the modem like a rc systems, for example connecting a gamepad to the laptop?2nd- Which knods of sensor can be connected to the analog inputs? Are there code prepared for that?3rd- Is ther a "newbie" guide to start in the paparazzi uav?4th- It´s possible to control the booz with the laptop?5th- The booz have autonomous navigation (with on air update waypoints?6th- It´s compatible with the paparazzi ground station??7th- Is ther a guide for the booz?8th- IS there a update forum of the paparazzisystems?Sorry for my "question attack" but I´m newbie with this systemsThanks for all.Yours faitfullyJesús
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Closed loop autopilot simulation with FlightGear - Part 1

Posted by Faisal Shah on October 19, 2009 at 10:30pm
I don't have the cash right now to buy a plane, ArduIMU, an auto pilot, and associated hardware. So, while I'm saving for the hardware, I want to play with the various algorithms out there in a simulation environment - to gain a deeper understanding and feel for it. I want to be able to code in C, so I can use the code directly in the hardware autopilot when I reach that point.I want to use a flight dynamics model to generate sensor inputs to the autopilot (3 axis gyro, 3 axis accelerometer, GPS - just like ArduIMU), and have the autopilot generate control surface inputs to the simulated plane in the flight dynamics model.Phase 1: Open loop. Tuning/experimenting with the AHRS algorithm. This would not require the flight dynamics model to accept control surface input from the autopilot. I would load the simulation and fly an airplane around in some pattern. The FDM would generate and log the sensor readings and the "ground truth" pitch-roll-yaw angles. My AHRS code would read in the sensor log, compute the pitch-roll-yaw angles, and would allow me to compare it with the "ground truth" data generated by the FDM.Phase 2: Close the loop. Use the autopilot to accept sensor inputs from the FDM, and send back control surface inputs.Right now I'm concentrating on Phase 1. Has this been done before? I've looked around a bit and it seems that FlightGear is well suited for this type of hackery. Are these properties the ones I should use to generate the correct sensor data, emulating an ArduIMU? How can I get the values I need out of FlightGear (I read that a UDP socket is used?).*Gyro sensors*/orientation/roll-rate-degps/orientation/pitch-rate-degps/orientation/yaw-rate-degps*Accelerometers*/accelerations/pilot/x-accel-fps_sec/accelerations/pilot/y-accel-fps_sec/accelerations/pilot/z-accel-fps_sec*ground truth data to be logged and compared with my own AHRS output*/orientation/roll-deg/orientation/pitch-deg/orientation/heading-degHow does everyone here test their algorithms before sending it up in the air? Anyone else run their autopilot code in a closed loop with a flight dynamics model? If not, I wouldn't mind putting in some extra effort to make this interface nice/easy-to-use so that it can be used by the community out of the box for autopilot testing.Thanks in advance!
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French micro plane fast forwards to hover

Posted by isobot on October 18, 2009 at 4:59pm
Hope this is not a duplicate post (I've seen it before somewhere)A mere 30 centimeters long, the MAVion combines fixed wings with two counter rotating propellers, allowing it to operate with high aerodynamic efficiency--even in adverse conditions, according to the professor.thought this might be of interest.http://news.cnet.com/8301-13639_3-10377358-42.html?part=rss&subj=news&tag=2547-1_3-0-5

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Developer

My UAV helicopter - vibration problems

Posted by Randy on October 17, 2009 at 10:58pm
Hello All,Like a few others, I've been working on a UAV Helicopter but I've hit a bit of roadblock and I'm looking for some helpful advice from the community. At the moment, when I try to fly the helicopter (so far as high as 4 inches off the ground), it tries as hard as it can to bank left because it thinks it's leaning at >40%. The problem is vibration and I'm looking for any advice I can get on how to overcome this problem.Below is some slightly massaged data from the accelerometers and gyros. The accelerometer data is adjusted back to "mid" so instead of values being from 0 ~ 1024, they're from -512 ~ +512. The gyroscope data has been converted into degrees per second (i.e. (raw gyro value - gyroMid)* magicNumber). The little table of numbers below the graphs is the average variation in accelerometer values I'm seeing..so when the helicopter is completely assembled, each x-axis acclerometer values is on avarege 300 away from the previous value!

I guess there are two roads to resolving this:1) reducing the actual vibration of the helicopter.2) use less vibration sensitive accelerometers and gyroscopesFor #1, I've done some loosening of the ball joints in the main rotor and upgraded some components to Aluminum and Graphite.For #2 I haven't done much. I'm using Sparkfun's 6DOF (http://www.sparkfun.com/commerce/product_info.php?products_id=8454).What do you think? All advice more than welcome.BTW, I've also been following John Mac's and Bill Premerlani work on CCPM Helicopters so I'm thinking of contributing to their efforts instead of going it on my own.

You'll see from the pic above I've incorporated a number of improvements suggested from my previous blog post including:- better mounting of the AVR 128 and sparkfun 6DOF (now on the back)- lipo batteryI've also upgraded the engine to a hyperion Z3025-06 because the previous one simply couldn't get this big-ish ECO8 off the ground. I've also replaced the "mechanical mixing" with "electronic mixing" -- this is ECO8 speak mostly I think but basically it means that now the three servos at the back, work together to control the pitch, roll and elevation of the main blades instead of using the ECO8's manual mixer thingmy which everyone says doesn't work very well.
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Above Sunnyvale

Posted by Jack Crossfire on October 17, 2009 at 10:30pm
Found a few safe landing zones in North Sunnyvale to lift off from. 1 area is closer to the subject of interest, but with higher risk of getting jammed.

Had a day job here in 2000, in a building which has since been destroyed& replaced. Our old man worked across the street in the 80's.

He got busted 4 trying to photograph a satellite dish near this bluecube. Now it's probably going 2 B torn down. Fly near it & U will be jammed.

Towards San Jose

400ft feels really low. Not likely to get any higher in this area.
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Best way to calibrate a pitot / Good way to estimate wind?

Posted by Tj Bordelon on October 17, 2009 at 4:06pm
I just added a pitot to my ezstar (http://bordelon.net/ezstar) and did a flight. Naturally the plots of the airspeed sensor and GPS velocity (projected onto the X axis... straight thru the nose) did not seem to match. But should they? I figured any wind would skew the results, so how do you know you're calibrated?I first tried to make a "manometer" with a tube of water but that seemed to just make a mess and was off by 50% in the end.I finally just flew with the manometer guess, and made 10 or so circles in the air. On landing, I took the data and scaled things to match as best as I could. Here's the result:

So they don't match. But there was a slight breeze that day. I then had an idea! What about plotting the wind speed (pitot - gps) vs bearing. I dumped a bunch of points to the plot and got this:

Mind you it wasn't symmetric about 0, so I played with the scale to make it so. I believe this was the best and most accurate thing I did to calibrate. Because once I did this, I then went and flew in 20 mph winds... and guess what! I got this:

I also verified that the direction of maximum/minimum "wind" was the exact bearing and speed of the wind I measured just before takeoff.So what's the problem? Well, I talked to a few guys I used to work with on a UAV project and this just confused them. So I figure I"d ask you guys out the'e what you do to make sure your pitot is calibrated, and if any of you have a good method for wind estimation. Does my technique look like what you do?
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Telemetry testing

Posted by jaron on October 17, 2009 at 4:12am

I spent some time on the software for the ground control station lately and did some telemetry flights with my UAV Flying Wing.Nothing special but I thought I'll post this anyway so people know that I'm still alive. The software is a work in progress and I'll post some information about it later.Ground control station- XBee Pro (RP-SMA)- Duck Antenna (RP-SMA)- XBee USB adapterIn flight- Arduino Mega microcontroller- DIY shield for the Arduino- GPS module EM-406A- XBee Pro with wire antenna- XBee Pro adapterThe XBee modules I'm using for the tests are surprisingly easy to setup and use. They act just like a regular serial interface and I'm using my SimpleSerialization library for the Arduino to transfer the telemetry data.

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For visualizing the data in GoogleEarth I'm using the KMLProvider of my UAV Playground project.

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The next step will be the integration of the IMU, but I haven't decided yet which one I'm going to use.
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Connecting an ardupilot card with a datalogger?

Posted by Nathan Woody on October 16, 2009 at 7:13pm
I'm currently trying to connect a Sparkfun logomatic v2 serial datalogger (WIG-08627) to the ardupilot card. I understand how to do it using anolog connections ,but I can't figure out how to do it through a serial connection. Does anyone know how to connect the ardupilot with the datalogger using a serial connection?
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The dry Stanford lake bed

Posted by Jack Crossfire on October 16, 2009 at 12:00am
is a long long long drive from the east bay on 25mph roads. Then on weekdays you're greeted with permit parking only, anywhere within 1/2 mile of the lake bed. Fortunately, U can park in the golf course parking & walk 1/2 a mile to get in.It has scattered tall weeds, making landings tricky.

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It's a very large area with spectacular views from 400ft, if you've come prepared as we have.

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These R all 8 megapixel images. Because we're using a very aggressive takeoff program, sometimes these overshoot to 426ft before settling at 400ft.

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This 1 has the free parking.
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