Engineering Issues

In the coming days I will post some time lapse video of the actual multi-rotor frame build.  The build went very well and I didn’t have any problems.  But when I added the gimbal to the bottom of the multi-rotor I soon noticed a pretty big problem.  The landing gear which I had envisioned using, and had already purchased, was very obviously not going to work.  It was purchased for its price and I had used it in a previous build with some success.  You can find it here.  I found that when the gimbal was mounted to the frame of the multi-rotor there was just no viable place to attach the landing skid mounts.  So I had to scrap them and figure out another way to accomplish the same goal.

While researching a solution I came across a YouTube channel made by a gentleman who used a similar multi-rotor frame to the one I was using and he had come up with his own solution.  He used Sketchup and a Printrbot to make his own leg extensions.  His designs, though promising, proved to be too flimsy and short for my application.  This gentleman does, however, have his own forum and after searching around it I came across another gentleman who had made a much more robust design that snapped and bolted together.  Not only that, but he had made it available on Thingiverse.com.  I downloaded his models and soon realized that the design was for legs that were about 13.5 CM in length.  I needed something closer to 20 CM.  Not having the knowledge to modify his design I found his YouTube page and sent him a private message asking for his help.

His name is Gavin Bendtsen and he was kind enough to email me back.  Not only that, but he went out of his way to modify his plans to fit my application and had them back to me by the next day.  A soon as I got the plans I went to work.  With the help of Mariano Ulibarri I got the legs printed and they came out very nice.

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I went about mounting them to the multi-rotor frame and found that I only need to make a few small modifications.  I had to use an old soldering iron to melt several small indentions at the top of each leg piece to accommodate the motor mounting bolts.

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With the modifications done I began fitting them to the frame.

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Here is one leg finished.

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All finished.

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The legs seem flexible yet very sturdy and provide more than enough height to allow for the gimbal to hang underneath.  I am very thankful that Mr. Bendtsen was able to assist me in this endeavor as there is no product like this on the market.

This collaboration also shows a very important part of what makes any project like this successful. That is with help and collaboration from the community as well as the rise of at home design and manufacturing, one can accomplish just about anything.  May the makers of the world continue to unite and thrive.

 

More On The Gimbal

Here are a few more details regarding the camera gimbal build video I posted previously.

An important part of this project is making sure that the multi-rotor is built at minimal cost yet remains of substantial enough quality to perform all needed tasks.  That being said, finding a high quality gimbal at a low price can be very hard.  Gimbals range in price from $40 dollars into the thousands.

After much research I came across a servo controlled 2 axis gimbal that looked like it could easily be modified to mount on the frame I selected for the build.  It was also very inexpensive – around $37 dollars.  The gimbal can be found here.  they have several nice pictures of the fully constructed gimbal.  It is important to note that servos were not included nor did they state what size of servo would be needed.  When it arrived it looked a little less constructed.

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There were also no instructions included.  Though I shouldn’t complain.  I wasn’t certain I would receive the order at all being as the vendor’s name is Goodluckbuy.  So I started putting things together using the photos on the vendor’s site.  Slowly it started taking shape.

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Things went mostly according to the plan my mind had made, though i did struggle with some quality issues.  The ball joints and bolts designed to be the actuating arms didn’t actually fit and had to be tapped and glued together.  But that was about the only snag I came across at this point.

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After several hours and lots of tinkering I had something that resembled the completed product.

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You can see the aforementioned arms in this rear view.

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All in all the build went very smooth and mounting it to the multi-rotor frame was very simple.  Just four holes 3.5 mm in diameter and four M3 bolts with locking nuts.

For the price, I am so far very satisfied with this gimbal and I am fairly confident it should get the job done.

The Build

For the most part the multi-rotor I will be using has been built and in coming weeks I will be posting video and pics of the whole process.  I will be discussing a range of topics from, parts needed, back ground of the hardware used, theory, and best practices.  I will also discuss engineering issues and how I overcame them.

The idea being that when I am done I will have an aircraft that is stabilized by an Arduino based controller board.  The aircraft will feature a 2 axis, servo stabilized, camera gimbal capable of carrying a compact digital camera.  The camera shutter will be triggered by an additional servo mounted on the gimbal and controlled by the transmitter.  The multi-rotor will also feature an additional camera that will transmit live video to a ground station which will in turn broadcast to a pair of video goggles so that the aircraft might be flown as if the pilot is sitting in the aircraft.  This allows much more precise flying.  The aircraft will also broadcast live telemetry information to a laptop which acts as a flight recorder and will give the pilot the ability to tweak configurations on the fly.

If all of these systems can be made to work without error this multi-rotor will be a valuable tool for gathering photo based data to be used in the application of photogrammetry on a large scale.