Ohohia - The Pacific-Crossing Attempt

I arrived in Tucson last night after a long drive from California. I just missed a big storm, apparently - lots of downed power lines, flooding, etc. I was so looking forward to a good thunderstorm, and I missed it! Oh, well, there will be others.

I just got back from visiting the Aerial Robotics Club at the University of Arizona, where I checked out what they were doing. They have an autonomous Eagle 2 and a couple of helicopters that they are preparing for flight on Saturday. Unfortunately, I may not get to see them fly on Saturday, as I have already made other plans for that day. I wish I could see them fly! I think it is so cool what they are doing. It makes me want to move back to Tucson and go to the U of A so I can participate in it.

However, following my visit, I had thoughts of abandoning this project. Mostly for personal reasons. If I were younger and going to school and plugged into an institution or other reputable team or whatever, I would feel much more able and motivated to pursue this project. As it is, it is becoming more of a burden than a joy. And seeing as it originally emerged as something I wanted to do for fun and how the level of enjoyment decreases as I delve into this further (especially alone!), I can't help but consider putting this project to rest.

I still intend on exploring the technology, etc., but just at a much lower priority and intensity. Who knows, that might be the trick to actually making it happen. But for now, I feel that my focus is turning away from "THIS PROJECT" and toward more joyful pursuits. Like actually flying my airplanes! Over the years, I will add little bits of additional technology (and perhaps by then, more off-the-shelf, affordable auto-pilot products will become available). But as of now, I think I am returning to the relaxing aspects of the hobby. And I hope to do some night flying while I am in Tucson. Woo hoo!

I've been thinking a bit about what I need on this project, and would like to assemble a team, since I need help with some of it. Here are the areas of knowledge that will be needed for this project:

• Meteorology (esp. regarding the Pacific Ocean wind currents)


• Telemetry systems


• Embedded systems design/integration


• Internal combustion engine technology (that would be Dave)


• Electronic circuits & systems (esp. custom circuit design for controlling peripheral power & integrating sensors)


• Composites - custom lightweight strong materiels for airframe


• UAV technologies - specifically in regard to auto-pilot control

I will be seeking help in various segments of these knowledge areas, preferrably from people who live in the San Francisco bay area near where I live. If you think you have something you can contribute to the project, please go to my RC Night Flying site and look for my contact information to send me an e-mail message.

Thanks!

I went to a party tonight and met some nice people - a number of whom expressed interest in seeing my airplane succeed. Time will tell. At least nobody flat out said, "you're crazy!" Then again, perhaps that goes without saying.

Here are a few of articles about the success of the TAM5 model aircraft across the Atlantic:
From the B.B.C.
From the AMA - this story may roll off the page in time.
AZCentral.com
globeandmail.com
Sun-Sentinel.com

I was thinking about Ohohia today and realized there is a considerable degree of probability that the plane will wind up in the Pacific Ocean. In the event this were to occur, it would be nice if there was some possibility of recovering it - or at least tracking it for a while until it finally dies.

By design, the electronics payload will be sealed in a watertight canister to ensure two things:
1) That the plane will remain afloat if it goes into the ocean.
2) That the electronics will survive a dip in the sea.

The canister will also provide a stable environment for the electronics, making it easier to maintain stable calibration settings for certain sensors. At least in theory.

So here is a complete wish list of components and sensors that I would like to have on the aircraft. This is not a realistic list, but will merely serve as a starting point. It will be pared down to necessity, but hopefully with room for at least one or two "luxury" items.

Component List:

• IMU (required)


• GPS (required)


• RC4 (required)


• Telemetry data & command transceiver (possible digital image transmission as well)


• Tiny video camera with video frame capture


• Engine exhaust temperature sensor


• Engine RPM sensor


• Alternator voltage output


• Compass heading


• Altimeter


• Air speed sensor


• 6-point minimal LED lighting for nighttime navigation


• XENON strobe for visual indication


• Internal canister temperature sensor


• External temperature sensor


• Electronic fuel mixture adjustment (micro servo?)


• Fuel level sensor


• Battery level/condition sensor


• Battery charge/discharge indicator


• Internal moisture sensor


• External moisture sensor


• Supplemental solar cell

I want the on-board system to be able to detect problems and report them in the event something goes wrong. If the mission fails, I want to know why. Being able to transmit an image from the airplane's perspective could provide much useful information as well. Therefore, I would like to position the camera somewhere where I can at least see the prop. Also, although there is no guarantee that the aircraft would remain upright if it went down, it would be nice if it could continue to take pictures even after it goes down (if it goes down).

By having separate sensors to detect engine RPM, engine exhaust and alternator voltage, the system can distinguish between sensor failure and a critical failure. If the RPM goes to zero, but the exhaust temperature remains up and the alternator is putting out power, we know the RPM sensor was lost and the engine is still running. Similarly, if any one sensor dies, good reading from the remaining two sensors will indicate this. If all three drop, then it is pretty certain that the engine has quit running. At that point, the system can take a quick picture (for verification) and transmit it back to home base before it goes down.

The idea of having a small solar panel is so that if the plane did go down, the system would detect this and go into a sleep mode, shutting down all systems. The solar panel could soak up some energy from the sun during the day, either putting it into the batteries, or charging up a small super capacitor, to maintain or extend the life of the on-board systems. The system would then periodically (like once every two or four hours during
daylight hours) fire up the telemetry systems to collect GPS info and other sensor data and transmit it before going back to sleep.

Perhaps during these telemetry bursts, it could activate the data receiver for a couple minutes, waiting for commands from home base. If it hears nothing, it goes back to sleep to recharge. Otherwise, I could send it a command to take a picture, turn on the XENON strobe, activate the homing beacon, or whatever, before telling it to go back to sleep. Maybe even give it a schedule for future telemetry bursts.

There wouldn't be enough power in the batteries to keep the main processor running, continuously, so this complicates things a bit. Although, I don't know what SBCs are around these days that have standby features that could put it in a minimal power mode that might fit the bill. But since I have a VERY limited budget, I may have to resort to using a microcontroller to control the power of the main board. But this adds another potential point of failure that makes me very nervous. For now, this whole idea is on the wish list and is not critical to the mission. But it is fun to think about. I feel like I'm planning a NASA mission. I want to be able to communicate with my probe!

I figure the moisture sensors will be useful for two reasons: 1) to determine if the airplane is flying through some rain, and 2) to determine if the airship is taking on water (if it has gone down).

I expect to have a useful Flash or Java interface on a web site during the flight so that people can tune in and see the latest telemetry and images.

Well, more later as I think of it. Too many distractions right now.

I picked up a free 14" monitor today to stick in the corner to use with my laptop that has no screen. This will be my embedded development station for the flight system. The monitor is crap, but it will suffice for a while. Although, I saw a nice 15" DigiView monitor (5 of them, actually) for $5 apiece at a thrift store in Burlingame. If this one drives me nuts too much, I'll pick up one of those. I assume it would work better than a free one.

I have obtained a couple of '386 computers with a PC/104 platform that I will be using for initial testing and development of the flight system. Hopefully, I can find something smaller & lighter when the time comes to put a system together for the actual aircraft.

I will be performing initial tests of RC4 hopefully at the end of this month if I can find and fix this bug I am having with the BasicX-24 module. For some reason, I am unable to get COM3 to talk to RC4 at 19200 bps.

The early tests will consist of gathering data. With RC4 in the loop, I will be able to sample the R/C signals sent to it from the ground so that I can analyze the servo position data to determine the flight parameters for the aircraft. I will be doing my initial tests with my Eagle II.

Currently, I have the '386 computer (with a flash disk), the BasicX-24 module, and RC4 to work with. I am researching available IMUs (inertial measurement units) now in hopes of finding something off-the-shelf that is small, lightweight, and reasonably accurate (and, preferably, has some way to periodically calibrate it in flight based on other data from the GPS, etc.). But the GPS is a ways off. I first have to get the basics down for stabilizing the aircraft, then I can think about navigation.

Testing will progress through the following [preliminary] phases:

• Phase I - Test RC4 functionality & usability
  
• Phase II - Record and play back a simple flight maneuver
  
• Phase III - Extensive data gathering with IMU & other sensors installed
  
• Phase IV - Data analysis & initial design of flight control software
  
• Phase V - Develop flight control & navigation software & firmware
  
• Phase VI - Autonomous flight tests
  
• Phase VII - Long-distance autonomous flight tests
  
• Phase VIII - Cross the Pacific
  

Engine and alternator enhancements will be implemented and tested in parallel to the above plan, with implementation details addressed as necessary.

Welcome. This begins the journaling process for project Ohohia. Ohohia is a Hawaiian word that loosely translates to "flying spirit". It is what I am going to name the model aircraft that I am developing that will fly (all by itself) from Hawaii to California - almost 2300 miles. This is no small feat for an airplane that will weigh 11 lbs or less.

TAM5 of the STAR team completed an 1888-mile journey from Newfoundland to Ireland in mid-August of this year (2003). I was glued to my computer screen waiting for updates as the airplane slowly made its way across at somewhere around 50 miles per hour (43 MPH when the air was still and calm).

Although my crossing would establish a new distance record, it is not the recognition I am after. I just have a yearning to know what it is like to achieve such an accomplishment. If I am going to do it, I may as well make it official. I certainly want to make it more of a public affair than the TAM5, because I think it would be interesting to people if they could watch the event unfold online.

Some people would be urging it on, rooting for it, hoping that it will complete the distance. Other people will be just waiting for it to disappear - and expecting it to - hoping to have the experience of being able to say, "I told you so!" Others may peek in and wonder why time is being "wasted" on such a silly project. Others will want to know how it was done. The point is, such events are a different experience for everyone.

I want people to be able to share in the experience - whatever it means to them - by being able to view live tracking data online while the event unfolds. I am hoping to be able to send back images from the airplane as well, as I think it will have a greater impact by seeing things from the airplane's perspective.

The Transatlantic crossing attempt by the STAR team was reported on Slashdot before the event took place. It was amazing to see how many people chastised the idea, thinking it was idiotic (among other things) and was doomed to fail. I mean, how could a model airplane with only 5 lbs. of fuel go 1888 miles? How preposterous!

But they made it!

My goal is nearly 2300 miles - over 400 miles further than the TAM5! I am in the very early stages of research. I have not yet determined if this distance is possible. I believe it is, but the verdict is still out on that. For one thing, the air currents in the Pacific where my plane would be crossing is very different than over the Atlantic where the TAM5 crossed. It will require spending considerable time studying the weather patterns to determine when the best time of the year would be to make the attempt...and in which direction (HI to CA, or CA to HI).

My friend Dave is an expert with internal combustion engines. He has made many enhancements and improvements to small engines to increase their run time and efficiency, while at the same time increasing their power and reducing weight. Based on a rekindled idea he had some time ago, he is currently experimenting with a new fuel option that is expected to become the magic potion we are looking for to make this crossing possible. If it works, it will merely be a question of desiging and building the airplane (and the control system it is to carry).

The control system is what I am currently working on, and have been actively developing over the last year and a half. As with all projects, it seems, this one has taken longer than expected, already. According to my original plans, I should be making the crossing attempt in about six months from now. But, now it looks like it might be another year or two.

I also need to start looking for funding, especially since I have been laid-off since April and have had great difficulty finding a new job in the Silicon Valley area. It is very expensive to live here, so my projects have been suffering greatly. I may wind up moving, which will cut into valuable development time as well.

Anyway, I will report my progress and items of interest regarding the project, in this blog. If you have any interest and necessary skills to contribute to the development of a small autonomous airplane, I would like to assemble a small team for this project. It seems a bit too much for me to do on my own, and having a motivated teammate always helps keep things moving.

For more information about one of the components of this project, look at RC4. This is a critical component that will allow me to switch between auto-pilot and manual (R/C) control at the launch point and the landing point.