Hello, does anyone have an idea how to stop the motor one second or something before releasing the shutter to reduce vibrations on a plane for photomapping. After the photo the motor should spin up again automatically.Does anyone have an idea?
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yes, I have a small wing (90cm) for mapping and I want to get the maximum quality out of the cam. The plane is small because I have to carry it quite a long time (5 to 10 hours path in alpine region above 3000masl) to get to the areas to be mapped.
I hoped that there is already a parameter or method to stop the motor one or two seconds before releasing the shutter and continue spinning after the photo was taken.
Of course the motor and the prop should be ballanced well to get a good result as well!
And JB that ist right, I am comparing my plane with sensefly ebee. And they stop the motor when taking a photo. But I don't know what FC the are using. Maybe something like PX4.
remember that eBee is a consumer level product, made to fly "ok" for anyone, and expected to have less gracious "landings" - work with small/cheap camera sensors (at longer exposure). They only need to perform not-very-much-less than the promised "best case" advertised flight endurance.
This, however is a place where professionals and builders share advice, and it's clearly the best advice for flight time, efficiency, and performance in wind to refrain from jerking the throttle around. BTW, be sure to set a short exposure time, 1/800 to 1/1500 should be fine, depending on your camera.
It's not the the price tag that defines quality or technology.
What eBee customers are paying for, not technology or quality, it the price for not needing to acquire RPAS or stitching related competence, it's a plug'n'play solution that "anyone can use", not comparable to endurance, reliability and quality professionals in other fields can deliver.
The sensefly ebee uses this principle for good reason, particularly for smaller airframes that are more sensitive for vibrations without being able to carry substantial damping/isolation etc. Even just the electric motor without prop produces high resonant frequencies that can distort images. Turning the motor off also turns the vibrations off. ;-)
In some ways yes, I don't disapprove of the idea but it will not help your flight times as you will use more power to accelerate the motor again that you will save in the shutdown period. my point is that the propeller is still windmilling with the motor off and so the vibrations are still there. It just makes more sense to remove the problem at the source than trying to get around it. I use X5 aircraft all the time and they are small (44inch ), never have a problem with balanced props.
Yes, I have to agree with you there Pascal in the case of frequent exposure survey flights. However, currently my flights would only require an image every minute or so once passing over a Point of Interest like cattle troughs etc.
For long gaps between images simply add an extra waypoint near to the intended point but at a higher altitude. the aircraft will climb to the new height and then descend slightly to the photo height with a slow motor.
The much better solution is to balance the props as Andre K suggests. Better for the pixhawk as well as you aircraft and camera.
Replies
thank all you for your replies!
yes, I have a small wing (90cm) for mapping and I want to get the maximum quality out of the cam. The plane is small because I have to carry it quite a long time (5 to 10 hours path in alpine region above 3000masl) to get to the areas to be mapped.
I hoped that there is already a parameter or method to stop the motor one or two seconds before releasing the shutter and continue spinning after the photo was taken.
Of course the motor and the prop should be ballanced well to get a good result as well!
And JB that ist right, I am comparing my plane with sensefly ebee. And they stop the motor when taking a photo. But I don't know what FC the are using. Maybe something like PX4.
remember that eBee is a consumer level product, made to fly "ok" for anyone, and expected to have less gracious "landings" - work with small/cheap camera sensors (at longer exposure). They only need to perform not-very-much-less than the promised "best case" advertised flight endurance.
This, however is a place where professionals and builders share advice, and it's clearly the best advice for flight time, efficiency, and performance in wind to refrain from jerking the throttle around. BTW, be sure to set a short exposure time, 1/800 to 1/1500 should be fine, depending on your camera.
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Andre K
If the ebee cost up to $30k and you call it a "consumer" level aircraft, what exactly are you flying to be professional? :-)
As gewe mentioned he's using a small airframe as he needs to carry it...the ebee type airframe for example weighs less then most SLR cameras alone.
It's not the the price tag that defines quality or technology.
What eBee customers are paying for, not technology or quality, it the price for not needing to acquire RPAS or stitching related competence, it's a plug'n'play solution that "anyone can use", not comparable to endurance, reliability and quality professionals in other fields can deliver.
The sensefly ebee uses this principle for good reason, particularly for smaller airframes that are more sensitive for vibrations without being able to carry substantial damping/isolation etc. Even just the electric motor without prop produces high resonant frequencies that can distort images. Turning the motor off also turns the vibrations off. ;-)
It's a reasonable request IMHO.
In some ways yes, I don't disapprove of the idea but it will not help your flight times as you will use more power to accelerate the motor again that you will save in the shutdown period. my point is that the propeller is still windmilling with the motor off and so the vibrations are still there. It just makes more sense to remove the problem at the source than trying to get around it. I use X5 aircraft all the time and they are small (44inch ), never have a problem with balanced props.
ESC brake gets rid of windmilling and extra drag. A short 2-3 sec stop won't deplete the battery much more.
But I do agree adding damping and balancing should be done first. No reason to solve a problem that doesn't exist. :-)
I shot every 2 sec for photogrammetry, stopping "one sec or so" each time the shutter is about to work would make a strange flight.
I agree with Andre, you should better work on vibration reduction.
Yes, I have to agree with you there Pascal in the case of frequent exposure survey flights. However, currently my flights would only require an image every minute or so once passing over a Point of Interest like cattle troughs etc.
For long gaps between images simply add an extra waypoint near to the intended point but at a higher altitude. the aircraft will climb to the new height and then descend slightly to the photo height with a slow motor.
The much better solution is to balance the props as Andre K suggests. Better for the pixhawk as well as you aircraft and camera.
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