Andrus Kangro's Page
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Andrus Kangro replied to Paul Mather's discussion 'HappyKillmore's Ground Control Station'
Hi, I'm very interested in generic Mavlink support by Happykillmore GCS. It is there by a large extent, but some commands do not match, like uav modes.
For example, mavlink protocol has 4 testing modes for MAV_MODE and I'm using 2 of them…
Andrus Kangro commented on Paul Mather's blog post 'HK's GCS now compatible with APM MAVlink'
Hi Happykillmore, you are doing amazing job with your GCS, its such a nice software.
Let me point out one issue you might not be aware of. You wrote:
@Krzysztof, I will investigate today. There is currently an issue with ArduPilot Mega and…
Andrus Kangro replied to Tonino's discussion 'HobbyKing?'
Hi, I've made 24 orders from Hobbyking so far and will do more.
I've had one issue - one order which I originally selected to be paid with Visa, I paid with Paypal, and this order did not go into "Processing" status…
Andrus Kangro commented on Andrus Kangro's blog post 'My autopilot'
I played with airspeed gain, but did not get it right in a way I liked it. I had best results when I adjusted gain (but not controller period) on the fly - when oscillation detection kicked in, then lowered it and when not enough control authority…
Zachary Hazen commented on Andrus Kangro's blog post 'My autopilot'
I wonder if combining a PID with airspeed based gain tuning would help, since the pitch response from elevator is a function of airspeed^2. Do you have a link to a CMT for controls explanation?
Andrus Kangro commented on Andrus Kangro's blog post 'My autopilot'
Hi,
the code was standard PID controller (controller period was 200ms, as servos could not react with shorter period) with Ziegler–Nichols autotuning. Since I moved to Cosinus Matrix Transform, I do not use it any more.
It worked just and…
Zachary Hazen commented on Andrus Kangro's blog post 'My autopilot'
Can you explain or show the code for your airspeed control via elevator? It is a little inderect, since elevator controls pitch, and then pitch control airspeed, but you seem to have gotten great soaring results! How well did it work for you?
Andrus Kangro replied to Joe Nix's discussion 'Cheap 6+ Axis Acc/Rate w/I2 interface, < $60 WII Nunchuck and MotionPlus'
Hi, motionplus is in fact 3-axis gyroscope (it has two-axis IDG600 + single-axis XV-3500 chips inside). Here has been a lot of discussion about it some time ago.
Andrus Kangro replied to mo fakahany's discussion 'Self-retrieving High Altitude Experimental Glider'
Their plane probably attempted to change pitch too fast, thats why there were G's.
Please also note, their glider "Cruise airspeed was 230 kph (125 kts) or more." (fly4)
and
"The glider's true air speed was only a little…
Andrus Kangro replied to mo fakahany's discussion 'Self-retrieving High Altitude Experimental Glider'
Hi, I think that this similar project you referenced provides quite a lot of valuable information. I would assume that main concern is cold and very high winds (jetstreams) up there, so you may want to look into airframe design that flies very fast…
Andrus Kangro commented on automatik's blog post 'Razor 6DOF IMU + Arduino + DCM'
Hi, if you integrate gyro output, does it smooth out? Maybe just increasing low-pass capacitor will help?
Andrus Kangro replied to Curt Filipowski's discussion 'Cold Weather UAV Sensors'
Hi, I find airspeed useful for determining desired bank angle when executing a turn. Also, airspeed + ground speed enable me to determine turn rate of the airplane from turn rate of gps:
plane_turn_rate=gps_turn_rate*ground_speed/airspeed
I guess…
Andrus Kangro replied to Curt Filipowski's discussion 'Cold Weather UAV Sensors'
Hi, what might be alternatives? GPS only is not good because of wind. GPS with wind correction may work, but gusty wind can still cause problems. Pitch control via accelerometers and open loop motor control then?
Andrus Kangro replied to Curt Filipowski's discussion 'Cold Weather UAV Sensors'
Hi, I think that most problematic sensor to maintain in working order in rain and cold is airspeed sensor, i.e. pitot tube. It needs to be in airflow and is therefore open to rain and potentially freezing temperatures. Full scale aircraft has heated…
Andrus Kangro replied to ZORO's discussion 'Cancel Acceleration due to motion??????????'
Hi, as I wrote, you cannot do just with accelerometer, you also need to use input from pitch gyro in your filter. Also, in real life, your pitch depends also on roll and yaw, so you need to use Direction Cosine Matrix to find out, how your plane is…
Andrus Kangro replied to ZORO's discussion 'Cancel Acceleration due to motion??????????'
Hi, this is fundamental issue with IMU's. In short, you need to use gyros + accelerometer for this task and may also use magnetometer. You may want to consult direction cosine matrix documents found here, as this is what you eventually need to…
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Andrus Kangro's Blog
My autopilot
Posted on September 3, 2009 at 7:00am 24 Comments 0 Likes
I received request to publish more information about my "custom" autopilot, used for TTT contest, so here it is:
My autopilot current version is 4. It all started when I received Welleman pic programmer & experiment board as Christmas present (to be honest, it was selected by myself). My initial interest was to make my sailplane turns more efficient and for that I needed to hold wings always crossed with gravity vector.
Initial autopilot (V1) was built around 16f627 pic… Continue
My autopilot current version is 4. It all started when I received Welleman pic programmer & experiment board as Christmas present (to be honest, it was selected by myself). My initial interest was to make my sailplane turns more efficient and for that I needed to hold wings always crossed with gravity vector.
Initial autopilot (V1) was built around 16f627 pic… Continue
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