Sunday, May 27, 2018

Final Blog (Of this school year)

This final week, I fixed the messed up flight (see video), tested position hold and RTL (return to launch), went a mission completely autonomous and successfully landed and took off in the middle of a set mission.


Clearly something was wrong with that flight. Even pretake-off you can already see an unbalance. This problem is critical enough to where the drone completely flips over without actually leaving land. To attempt to solve this problem I reconnected the ESC wires and labeled each motor and its corresponding ESC. Hopefully for more organization in the future, the wires will be easier to follow. Turned out, most of the wires were in the wrong spot on the PixHawk. Oops.. Correctly wiring it back together fixed the problem entirely.


The position hold did not work if flipped in mid flight. For some reason the drone would begin to roll towards the right. We tried to let it go and hope it would stop.. (SPOILER). It didn't stop, but thankfully in the "Position Hold" mode could be overridden by the manual controls. What did work, was using the flight mode before take off. Flip the switch, THEN take off. It held perfectly. (image: no hands on the transmitter, while the drone hovered, holding its position)


The other flight mode I tested was RTL, this would make the drone stop its mission, hover over the takeoff location, and carefully landed. It worked smoothly.

There were three different missions tested this week after the "general flight" issue was relieved. One was a simple mission that flew to four waypoints (like a path it must follow) around the football field. After that worked I added in something a little different. I added a land feature, following with a delay, and then a takeoff to continue to the next way point. This would represent a sampling sequence. Land and hold in the water, delay to run the pump and valve, and then takeoff. It worked (for the most part). The only difference would be the altitude. What did not work in this sequence was the delay. The 20 second delay once landed, was only a 2 second delay (at most). The takeoff was almost immediate once landed. I tried to decrease the time (seconds) by 5. For some reason the delay was longer. To account for the issue I tried to use ArduPilot (Mission Planner) instead of QGroundControl.

This mission would run the Land, Delay, and Takeoff sequence twice, just running from a new program. It did not work. The delay was too long. By then, the drone had disabled itself. We tried to continue the mission by setting the command through Mission Planner, but the drone re-homed. I jumped to the "RTL" switch without realizing that the waypoints were the same. Although I ruined the mission, something new was discovered. The "RTL" switch could override a mission. I feel like I discovered a hidden jewel. I'm glad I was quick to flip that switch.

After many fails, "pit stops," delay (issues), and more, the year has finally come to a close. I am not done with this project. I promised to myself I would finalize the Ala Wai Drone, and I will. I have a lot of work to be done: more testing with the GPS (maybe I create a dock that can change heights to relatively match the altitude of the tide), a better float solution (while still remaining more professional that a pool noodle), and have an autonomously working water sampling drone (possibly from a dock - just a random idea). I plan to work on it over the summer anytime I can. I will also be attempting to create a swerve pod as a summer project as well. This is not the end, it will be finished and polished into a final project whether it is done over summer or when I graduate.

As a side note ~ I will be presenting this at the EdTech Conference Tuesday, June 5.

Saturday, May 19, 2018

Progress...

This week I improved a few things to make parts either more secure, cleaner, and just better.  I cut out a plate for the GPS, rather than a cardboard piece, wrapped anti-slip tape around the ends of the carbon fiber spars (for the chassis and the motor mounting),  fixing the gland nut, and calibrating the compass a million and one times.

Before flying last week, I had to tighten each spar due to the motors spinning around the spar. It didn't stick. To account for the slip, I had to disassemble the chassis and loosen the frame to wrap anti-slip tape around the spar where the mount clamped on. After applying the tape, I figured I do the part where the motor meets the spar as well. Then I tightened the chassis again and now (theoretically) the spars will not rotate.


After I wrapped the tape, I had to pull up the ESC wires up again, and it broke the clipped nut on the gland nut (I cut it to fit around the wire, rather than de-soldering everything to tighten the gland nut. Now that the nut was not tightening it anymore, I super-glued it and it worked!



The wiring looked great, except I was using a cardboard-hand-cut plate to mount the GPS. To solve this I quickly CADed a circular plate and cut it out of black acrylic. Looks better than that cardboard.


The compass calibration was not successful for about a week. Ever time it would not go past the mid yellow zone. Compass calibration is when you calibrate the GPS compass (both external and internal) by moving the entire drone around in different orientations.


If you can barely see the white dot in the middle of the yellow section of the bar. Yellow signifies somewhat acceptable, but still risky to do any "position hold" commands. If the compass is not green, a rule of thumb is not to use those commands. All week for some reason the calibration would only be suffice to receive the yellow grading. I tried changing a setting that would allow for a greater offset for the calibration, it only helped get the dot into yellow, rather than red. In the end, when it finally worked, there was one big problem that prevented it to work from the beginning. I had plugged in the GPS cable into something other that 12V. For all the flight controller knew, there was no external GPS. Oops. As soon as I plugged it in correctly it was in the far left green (best it could be), meaning it is finally ready to use commands.

There is only one more week of school, and there is almost no way to finish the entire project before Friday. I will continue to pursue adding the sampling system (floats mainly) over the summer after finals. For the remainder of the week, I will work on the EdTech conference presentation, flying the drone, and testing a few commands such as "position hold" or maybe even an autonomous mission.

Sunday, May 13, 2018

It's Alive!!

This week I continued to configure and setup the drone via QGoundControl (Ardupilot) with the help of Timmy. First priority was to get the radio (receiver and transmitter) set up.

For the flight, I will be using the Taranis X7 radio transmitter. To connect it to the receiver, I went into the menu to find "BIND," and clicked on it so that the word would flash. From there I powered up the drone while holding down the button on the receiver. Once the drone was powered up and the button was pressed, a green light flashed on the receiver. I shut down everything and turned it back on. Instead of a steady red light, or a red light with green flashes, it was a steady green light on the receiver, signifying that it was connected.



Above you can see the Taranis X7, with the model "AWD" which stands for "Ala Wai Drone."

After this, Timmy aided me in setting up certain settings such as the throttle_max/min, yaw max/min (we don't want the drone to fall from the sky), and other parameters that I need to write down on Monday. From the receiver, he taught me how to set up which buttons actually send signals on the receiver. I will be using one switch to activate the sample system (most likely the button that only sends a pulse -- switch on right. using the single pulse switch will prevent having to continuously reset the switch before and after a flight.


Picture above shows the values of the throttle, yaw, pitch, roll, and switches.

Before flight, Memde and Timmy helped to calibrate the Compass (physically turning the drone into different orientations) in order to use telemetry.

Tips for compass calibration:
-be away from any large building
-do not try to calibrate it indoors -- waste of time
-if it does not work, try rotate slowly (but not too slow or else it will freeze up)
     -can change value of COMPASS_OFFS_MAX to higher - but do not exceed 3000 (sets maximum amount of compass offset)

Although the calibration only allowed the bar to reach slightly-less mid yellow, it was still better than in the red. The compass calibration is only necessary for the telemetry, which will be used by other users when it is finalized.



Although there were obvious problems with the compass calibration, my not-so-smol child has flown!!! The flight was extremely stable, especially with the wind. Super exciting!!

To do's:
-MUST REDO FLOATS
-SET UP ARDUINO SOON NAIA
-find an actual secure way to mount the batteries and GPS...

Saturday, May 5, 2018

Organized Electronics

This week I primarily worked on the vital parts necessary in order for the drone to fly, while working on other aspects of the drone.

First I water jet the plate holding the pump, valve, and sampling bottles and the plate that will fit inside the waterproof container.



After finally cutting out the final plates (unless I change it to carbon fiber over the summer). Then I replaced the wooden versions with the polycarbonate versions. 





Once all of the ESCs were wired onto the PDB, I made a connector from the..

PDB>Power Module>Connectors > > B1/B2

From there I spun up each motor and set the spinning direction. As of now, the only step left is attaching the propellers and calibrating the PixHawk 2.4.8.

Current State:




GOAL 1: fly 

Sunday, April 29, 2018

Wiring Up Motors

This week I mainly worked on soldering the motors -> 25in extensions -> ESCs.

In order to do so I had to drill a central hole that the gland nut would fit. Because there is limited space through the gland nut, I had to string the wires through before soldering the ESC's (ESCs are to be kept inside the waterproof container).



After all of the extensions were done, I strung them through individually to avoid confusion between different wires for different motors. Before stringing another wire set I soldered the ESC on. 



Once each motor was mounted and each ESC soldered on, I began (but did not complete) soldering each onto the PDB (power distribution board). 


Considering the mounting of the PDB, Mr. Emde discovered that the mounting holes on the PDB matched the ones for the PixHawk anti-vibration plates. This meant I could simply use longer screws and mount the PDB on the back side of the PixHawk plates. 


 All motors are mounted and wired to their separate ESCs.


Although my first goal is to have the drone actually flying, I should work on other parts (redo) such as the floats.

TO DO (priority)
-solder all ESC to PDB
-finish any last electronic work and test fly

TO DO (other)
-redo motor mounts (the ones currently in use crack easily)
-redo floats (instead, make into one solid float rather than 2)
          -try strengthen current one (tighten) -> if does not work then completely redo
-cut out electronics and sampling plate out of polycarbonate (.25)
-test out the sampling system separately to see if it still works
-redo tubing to adapt to different spacing

Tuesday, April 24, 2018

Electronics

The past week I worked on mainly the electronics due to the fact that all parts necessary arrived! Before doing this, I first created some structure within the polycarbonate container.

I used the outer hole of each tetrix star as the hole spacing meant for any extra plate inside the polycarbonate.



At first the spacing was not perfect - possibly due to play when I drilled the individual holes, causing them to not be perfectly spaced. I simply measured the distance needed on each side (which happened to be an equal distance of 3mm) and thankfully it turned out perfectly on the second try. This plate is designed to hold the PixHawk 2.4.8 and the GPS (GPS can mount on either side). Eventually I will need to remove the plate to drill the 1in hole for the gland nut and to install the rest of the electronics.

The other thing I mainly worked on was the motors. Although I did not get far I was removing the connectors and soldering on 25in of extended silicon wire.




This upcoming week I will finish the motor extender wires.


To Do:
-finish motor extensions
-drill center gland nut hole
-mount motors
-string extension wires through spars & through gland nut
-FC?


Sunday, April 15, 2018

Float Attachment and Lexan Gluing (attempts)

This week the project is beginning to look like a sampling drone.. finally. I attached the floats, received electronics (to be set up later), glued on the polycarbonate box, and began creating a BoM  (Bill of Materials) for the drone.

Upon attaching the floats, there were some prominent issues that was showed. For one, motors that were meant to be mounted on the outer part of the spar could barely or not fit with the placement of the floats. Instead of "winging it" when it comes to drilling holes that the connection spars and feet will be places, I will have pre-set holes cut out on the templates. Also, the floats were not rigid in place. It was able to tilt upon pressure from either side (could be due to the incorrect placement of the spars). I may need to redesign the floats to create a disk-shape, similar to past designs. The only difference will be the less water-absorbant more rigid material.



The next order of business was finally glueing on the polycarbonate container to the C channels connected to the frame, although it was not perfect the first attempt...
Before gluing the box... I had to sand the surface of the polycarbonate and aluminum to create a rough surface to attach.





FIRST ATTEMPT: silicon glue




(the box just completely peeled off. leftover glue peeled off nicely as well when preparing to try with a new adhesive)

RESULT: FAIL

SECOND ATTEMPT: 24HR EPOXY




RESULT: seemed to work?

The container did not peel off which was a good sign. Just to ensure the stability and to keep the electronics in tact, I will add in support screws (as shown below)





Goals for the upcoming week:
- redesign sampling plate (to allow accessibility to C Channel screws)
- create a electronics plan and understand how to set up
     - create structure inside the container (where is everything going ?)
- BoM/inventory

Sunday, April 8, 2018

Actually Assembling Parts!

This week I completed what I planned at the end of last week. I was able to take apart and reassemble the chassis with the new plate water-jetted..... (pictures shown below)




.....and electronics + other parts have been ordered for the chassis.

BOM (electronics +other ordered):
-1in step drill
-6 (ARRIS 4210 Pro 380KV) motors
-6 ESCs
-10 meters of 18 AWG silicon wire
-PixHawk 2.1 (with GPS included)
-RC Reciever


Other than the list of To Do's, I realized that the screws of the C channels connecting my polycarbonate container would not be accessible. The screw would not be reached because the spars are directly under two of the access points. I will be putting these as a rectangle instead so it can clear these spars. For the gluing of the C channels to the polycarbonate, I tested a couple more adhesives as well as epoxy again.



The last things I did to prepare for assembly once the parts come in (supposedly next upcoming week), is print and drill (3D printing prints a little smaller) the motor mounts.


Now that I have almost all the components to be assembled onto the chassis, that will be the next step. To put together all the electronics as soon as they are delivered.


Sunday, April 1, 2018

Chassis Demo/Assembly

These past few weeks I, along with my friend Mia for part of the time, worked on assembling and disassembling the chassis frame along with the sampling parts. Mia and I were assembling the frame of our own (aside from Timmy's), and although we were unable to fully complete it before break...

(completed parts, just not the full assembled drone)




....I was able to quickly add on the sampling-unique parts to Timmy's already-build chassis for a demo/presentation given at a FRC Competition for the Chairman's award.

Regarding the presentation - it went well, unfortunately the team did not win. Some other team mentors were interested in the incomplete drone (and they were the only people who noticed it lacked all electronics). It provided good practice for further possible explanations.

After the presentation, I along with Timmy took apart my parts and reassembled his battery holders. I took one day to finish assembling the base of the chassis (including the spars). Afterward, I realized that many mistakes in the assembly were wrong, also upon trying to see the placement of the box + c channels the spacing was off. A lip I did not notice until testing placement got in the way of a flat surface to glue the aluminum to the lean box. Due to this, I have to redo the design of the top plate of the chassis. I will need to take apart the chassis (which had to be done anyway) and replace the wrong plate with ones that have a better placement of the c channels.

I redid the plate out of wood (to test before water jetting aluminum).

Next steps:

-waterjet top chassis plate (aluminum)
-waterjet lexan sample plate (smaller priority)
-reassemble chassis (again)
-order electronics?


Sunday, March 11, 2018

Assembling a Chassis (and a visitor!!)

This week acomplishments/things done included:
- finish testing landing gear prototypes
-printed and assembled the gear onto the prototype floats
-began assembling chassis frame

The landing gear prototypes worked well, the clamping action was tight enough the clamps did not budge. In the end, it was a success:
 (clamped onto spar and inserted in the foam)
(part withtout spar or float)

Knowing that the last part of the sampling system was successful, I decided to print out the entire set of landing gear (chassis clamp, float clamp, landing feet). 


This print took around 16 hours. For asthetics purposes, all final prints will be done in black PLA.

Mia visited this week and was able to help assemble the landing gear onto the floats. 

With the landing gear assembled and the sampling system prototype assembled, there was just one problem, I had no where to install these systems. Due to this problem, I will be assembling a new chassis frame so each group (claw and sampler) could test their parts without scheduling issues. 

The other team had flown the chassis, and unfortunately many parts kept breaking. The chassis plates broke and so did many of their 3D parts. To hopefully provide better support for the plates, we waterjet plates out of 1/8 in thick aluminum sheets. 
After they were cut, they needed to be polished (we used orbital sanders and bench buffer to polish the faces and sides)

From there, the plates could be attatched to the sampling systen and C channels in replacement of the plywood cutouts.



The next step is to print out the spar holders that will be clamped in between the two aluminum chassis plates. 


Thanks to the help recieved this week, progress has been multiplied!

Things to be accomplsihed next week:
-make sure the chassis pieces are printed
-motor mount pieces (plates and spar clamps) are printed
-assemble the chassis
-test the floats (how much it acts as a sail) on the currently running drone

Final Blog (Of this school year)

This final week, I fixed the messed up flight (see video), tested position hold and RTL (return to launch), went a mission completely autono...