Ryan Beall's Blog (12)

Rapid Prototyping and Quick System Identification (part 3)

Research by Ryan Beall and Chaz Henderson:

I did a little more refining of the model from the data previously described/collected from the Pixhawk.  The following are the results of System Identification and PID optimization.

The overall performance of the bank angle controller was suboptimal for our first flights.  It appeared to oscillate in…

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Added by Ryan Beall on January 10, 2016 at 7:00pm — 8 Comments

Rapid prototyping and Quick System Identification (part 2)

Written by Ryan Beall and Chaz Henderson:

Data/Analysis

The flight data was logged on the micro sd card which was plugged…

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Added by Ryan Beall on January 4, 2016 at 6:00pm — 1 Comment

Rapid Prototyping and Quick System Identification (part 1)



Research by Ryan Beall and Chaz Henderson:

Background

I took part in a research endeavor to analyze many facets of…

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Added by Ryan Beall on January 4, 2016 at 6:00pm — 4 Comments

Arducopter Flight data needed

I have been working on an improved altitude estimator for a while here but have been having issues with implementation.

 

The theory works fine but as seen above in the FFT of the accelerometer data, there is a significant ammount of vibration/noise in…

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Added by Ryan Beall on January 26, 2011 at 6:02pm — 36 Comments

Improved Altitude Estimate

The barometric sensor alone in most cases provides noisy and drift prone measurements. I have been trying to come up with a simple way to implement a fixed gain filter to utilize the acceleration measurements from the accelerometers to help clean up the noise and also add a sanity check via sensor fusion.…



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Added by Ryan Beall on December 5, 2010 at 7:30pm — 26 Comments

Improved Wind/Position EKF

I posted this earlier but did some tweaking on it to compare the Extended Kalman to my Fixed Gain Observer filters. I haven’t finished the FGO position filter but am really starting to lean more on EKF because the performance really is significantly better.…

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Added by Ryan Beall on July 25, 2010 at 2:00pm — 6 Comments

Improved Heading Controller

https://www.youtube.com/watch?v=cipTQAUM-v4

Note** these are 100meter orbits with really strong winds to provide a…

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Added by Ryan Beall on March 31, 2010 at 11:35pm — 7 Comments

No Baro altitude filter for ArduPilot

I wrote down a napkin sketch of an altitude filter a while back and finally got around to testing it in the simulator. I designed it to improve the sensed altitude of the ardupilot. It is based on a fixed gain observer model and shows very promising results. The idea is to use the "lagless" airspeed sensor to give you a less noisy lagless altitude estimate. Enjoy!

K_alt = -0.01;

avg_aoa = 0.52*(pi/180); //alpha =…

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Added by Ryan Beall on March 8, 2010 at 8:18pm — 7 Comments

Position & Wind Extended Kalman

Wrote up a wind estimator today. It is based off of a simple model which requires very little inputs from sensors.

psi - true heading (not course over ground)

theta - pitch

airspeed

GPS lat and long

It is a simple model. The wind model has no dynamics which helps simplify the solution. This asusmption is mostly true beings the wind direction and velocity doesn't…

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Added by Ryan Beall on February 7, 2010 at 11:00pm — 35 Comments

Ateryx 2.0 - The happy medium



Here is something that might peak some intrest. I plan on selling my autopilot in the near future and would like to see if there is any intrest in my product.



The autopilot world is hard to attract the hoby level audience because of the steep price jump in higher performance systems. The cheaper approach is to buy the DIY kits and depend upon the opensource code to carry you along. My product is a happy medium between the… Continue

Added by Ryan Beall on December 7, 2009 at 4:00pm — 20 Comments

IMU nose Dive problem/solution

In Bill's recent pod cast he talked about how the imudevboard experienced a random nose dive or extreme over estimation in the pitch (theta) axis. His theory was that the noise due to engine/aircraft vibration was causing the gyros to give inaccurate readings. He said that he put the imu in foam and the problem went away. I don't know how repeatable his experience was or how many test vehicles this "technique" was run on, but I find it no… Continue

Added by Ryan Beall on October 14, 2009 at 3:30pm — 45 Comments

Ateryx is airborne and looking great! (homebuilt imu autopilot)





Ateryx 2.3 has been in different levels of development over the past year or so but I finally got some motivation to clean up some code and pull it all together.



Cloud layer has been at 800ft for the past three days so I have been weather canceled with my Navy schedule. Considering the UAV development is all low altitude stuff this was the perfect time to get some flights out on the… Continue

Added by Ryan Beall on September 24, 2009 at 9:00pm — 6 Comments

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