According to Randy the know issue of altitude loss after a high speed run is at its heart a frame issue.This seems to me a very worthwhile discussion to have.Once the majority of us understand this, we will be less likely to muck up other threads.Take it away Randy...
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it also has a lot to do with your thr_min and thr_mid parameters, set thr_min to the lowest possible setting which will spin your motors, than adjust thr_mid accordingly. I think what it does it increases the resolution of the PWM signal, so more fine throttle control is possible. Also, oneshot125 improves throttle control in stab mode noticeably even on relatively low KV motors - 900kv, this translates in better alt hold performance.
I think it's all of the above. I added a plexi glass cover over my pixhawk and it instantly solved the problem so it's definitely not just aerodynamics but air pressure. After all it uses a barometer that can detect the difference in pressure in under a meter!! So it's a sensitive little bugger...
I have an update on the Gill static pressure port 3D model. I've continued to work on the design and manufacture. At this point I believe that I have a feasible, cost-effective solution. The 3D print house, Shapeways offers relatively high resolution prints at a very competitive price.
Here is a link to an updated pressure port model that can be purchased from Shapeways.
I'd like to enable an external Baro I've installed on my I2C bus but don't see the parameter GND_PRIMARY in any of the GCS apps (have checked Mission Planner, APM Planner and QGroundControl). Any ideas how I can switch to the external Baro or even a way to see what Altitude output it is providing as a test?
probably best to load up master on the board for this test. so if you're using the mission planner, go to the Install Firmware page and press Ctrl-Q. With this bleeding edge software at least, you'll certainly find the GND_PRIMARY parameter in the full parameter list (or full parameter tree).
Randy, I've been flying 3.4 today on my sawn-off (330mm) Turnigy Talon v2 framed quad (with AUAV-X2) and I must say it flies beautifully. With the external Baro, I get a much smoother lift off in AltHold than with 3.3.3 (with internal baro), the lift off is very decisive on raising above 50% throttle, whereas with 3.3.3 doing the same, the revs actually drop, then raise (like its recovering from some pressure related confusion), then it launches, but its definitely not as steady as with 3.4. Great work! As always with much respect and thanks, Paul
Replies
Thanks for the feedback
it also has a lot to do with your thr_min and thr_mid parameters, set thr_min to the lowest possible setting which will spin your motors, than adjust thr_mid accordingly. I think what it does it increases the resolution of the PWM signal, so more fine throttle control is possible. Also, oneshot125 improves throttle control in stab mode noticeably even on relatively low KV motors - 900kv, this translates in better alt hold performance.
I think it's all of the above. I added a plexi glass cover over my pixhawk and it instantly solved the problem so it's definitely not just aerodynamics but air pressure. After all it uses a barometer that can detect the difference in pressure in under a meter!! So it's a sensitive little bugger...
I have an update on the Gill static pressure port 3D model. I've continued to work on the design and manufacture. At this point I believe that I have a feasible, cost-effective solution. The 3D print house, Shapeways offers relatively high resolution prints at a very competitive price.
Here is a link to an updated pressure port model that can be purchased from Shapeways.
https://www.shapeways.com/product/EXUARQ4AC/apm-pixhawk-external-st...
The material is a scintered nylon, and several color options are available.
I'd like to enable an external Baro I've installed on my I2C bus but don't see the parameter GND_PRIMARY in any of the GCS apps (have checked Mission Planner, APM Planner and QGroundControl). Any ideas how I can switch to the external Baro or even a way to see what Altitude output it is providing as a test?
PaulA,
probably best to load up master on the board for this test. so if you're using the mission planner, go to the Install Firmware page and press Ctrl-Q. With this bleeding edge software at least, you'll certainly find the GND_PRIMARY parameter in the full parameter list (or full parameter tree).
Randy, I've been flying 3.4 today on my sawn-off (330mm) Turnigy Talon v2 framed quad (with AUAV-X2) and I must say it flies beautifully. With the external Baro, I get a much smoother lift off in AltHold than with 3.3.3 (with internal baro), the lift off is very decisive on raising above 50% throttle, whereas with 3.3.3 doing the same, the revs actually drop, then raise (like its recovering from some pressure related confusion), then it launches, but its definitely not as steady as with 3.4. Great work! As always with much respect and thanks, Paul
I wonder how is results with Zubax GNSS 2 GPS with HMC5983(temperature resistant) and barometer on itself?
https://zubax.com/product/zubax-gnss-2
Any news about altitude loss with Zubax GNSS 2
...or how to connect or use this mag-baro combo
http://www.goodluckbuy.com/gy-652-hmc5983bmp180-4-axis-flight-contr...
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