We’re learning how to research, design, and create with robots. Here, we’ll post our projects, our processes, our mistakes, and other related things that interest us. Virginia + Aria, designers and amateur flyers contact: ariaritz or vmbyers at gmail.com
This site will mainly be project updates and instructional stuff but we do like to share projects we come across that we feel are pretty great. This project byAsher J. Kohn is exactly that. It’s clever and well thought out. I also have a soft spot for Safdie’s Habitat 67, a project Kohn uses as reference.
I’d like to send out an open offer to Kohn though if he has any future drone/architecture theories give us a call. We’ll help you out with renderings and font layout ;)
Our flights have been really shaky and unpredictable, so we decided to tune the PIDs in Mission Planner as per these instructions: https://code.google.com/p/arducopter/wiki/AC2_Tweaks
To tune it indoors, we tethered it with bungees like this:
The bungees allow us to play with the control settings without fear of losing the copter.
We don't fully understand what we're doing yet, but lowering some of the numbers they suggested tweaking (thereby lowering the gain or responsiveness to the controls) seems to have improved our quad's performance, making it less jumpy and more stable.
This guide seems a little easier to follow, so we might give it a try to get a better grasp on what we're doing: http://diydrones.com/forum/topics/arducopter-tuning-guide.
Biggest rookie lesson yet: You need an RC transmitter
Some of the instructions available online make it seem that a computer-based ground station is adequate for flying your drone. It's not. Adding a joystick game controller to your computer won't make it so, either.
YOU NEED A REMOTE CONTROL TRANSMITTER.
This is a big enough no-brainer for people that know about these things that it goes pretty much unmentioned, but we think it's worth mentioning as YOU CAN'T FLY YOUR DRONE without it, and it took us weeks to understand that.
First of all, you need the transmitter to calibrate your ESCs and arm your motors. You won't get the drone off the ground without it. Second of all, It's possible to take over flight control with your computer and telemetry kit, but the connection is tenuous, and you need a reliable back-up.
We use this flysky. It works ok, but it doesn't have as many channels as we'd like. If we had a bigger budget we'd go for a spektrum.
We assembled our quadcopter from a kit, which included an electronics package that basically just needed to be mounted and plugged in. Our primary reference was this website, which is easy to follow and full of comments that address many of the problems you'll encounter (really, these forums and others you'll find on the web are invaluable):
It's no longer being maintained, though. The new site, while cleaner and easier to navigate, doesn't seem to have the wealth of information yet.
For now, I would recommend using both in tandem.
UPDATE: as we posted earlier, 3D robotics has released this assembly manual. It would have saved us literally days of deciphering inferior instructions. Check it out.
APM - Ardupilot Mega. Ours is version 2.5. The latest is 2.6. This is the system we're using, but others on the market include the Naza and DJI's system. This is the hardware that runs the drone, its brains.
RC - Remote Control. duh?
Deans plugs or connectors - this a type of electrical connection. A lot of people have strong opinions about these as opposed to XT60 connectors. A quick google search will bring you to pages and pages of debates about the relative merits of each. We've got both on our quad.
ESCs - Electric Speed Controls. This is the circuit that transmits power from the power distribution board to the motors. It allows you to vary the speed of the motors. Typically, it will have a low-voltage cutoff point, so that if the voltage drops below a certain level it will cut power to the motors, protecting the battery.
PDB - Power Distribution Board. The PDB splits power from the battery and sends it to each motor via an ESC.
Power module - NOT the PDB. The power module connects the battery to both the PDB and to the APM. It powers the motors via the PDB and it powers the APM, which it is attached to with a 6-pos connector. The power module also monitors current and voltage.
Servos - A servo is a small motor that controls a mechanism or system. In this context, it often refers to the servos that control gimbal rotation (camera angle).
Gimbals - A gimbal is a support system that can pivot around one or more axes. In the context of a drone, it most what holds the on-board camera.
UAV - Unmanned Aerial Vehicle
XT60 plugs or connectors - a type of electrical connection (see Deans above).
Even though it seems like we’re really just starting out it partly has to do with a little bit of a back log on our “how to” guide. We started this research partly funded by a grant from Flux Projects. I’m excited to say that as of last night we got our final approval on safety and location. So we're offically on the roster for Flux Night 2013! I don’t want to give away too much of the surprise but stay tuned for more videos, images and quad experiments.
Also if you’re in the Atlanta area and want to check out our project here is a little synopsis and join us October 5th from 7pm-12am.
Ok, so the prop fell off. The fix as it turns out was a multiple step problem.
First of all you want your blades to be right meaning no wobble when they are on the motors. The correct blades for this model should come with spacers that will hold the blade on tight. Ours were snug enough that we had to screw them onto the threads.
Second the hardware that came with the 3D Robotics kit was not staying on in flight. I'm not quite sure why this is happening but I suspect that it's something to do with poorly matched hardware. We eventually made a trip to Ace Hardware and bought extra 3X5mm screws, nuts and wingnuts.
Ok so now that you've seen how we put this thing together and read about some of the challenges you might be thinking "ok, quad put together time to get this thing in the air. Throttle up easy peasy...". Well you've be a bit off. In addition to learning the RC controller (more to come on that) we had some issues with the bolts on the props. Somewhere in the depths of instagram there is a photo of me on my hands and knees looking for the missing pieces. Check out the video above and I'll explain more about the solution in our next post.
Because our PDB came pre-soldered, we had to skip a few steps, but once we figured that out it was just a matter of screwing pieces together.
This is the assembled frame, with the PDB and the motors mounted. We used two blue arms to indicate the front because we'll be flying it in an X configuration. You can see how we've labeled each arm with drafting tape so we're sure we attach the correct propeller to each and connect each to the right PDB plug, as per the manual's instructions.
The next step was to connect the motors to the PDB via the ESCs.
We ordered a PDB with deans connectors, so we had to solder plugs onto each of the ESCs. Here, Virginia solders one of the ESCs to its deans plug:
Then all that was left was to plug the ESCs into the PDB.
You can see the propellers attached to the motors and the ESCs zip tied to each arm. We left the wires loose at this point because until we calibrated later we weren't sure we had attached everything correctly.
We're learning how to research and create with drones, robots, and other unmanned tools. Here, we'll post our projects, our processes, our mistakes, and other related things that interest us.
