August 20 progress passed!

Yesterday Yukari 4 passed the August 20 progress verification point. A whole 15 days early, too. Here is video proof:

June 6 test

This is a simple open-loop test. It runs purely on timing:

1. Five second delay after reset
2. Throttle up and wait two seconds
3. Turn hard right and wait one second
4. Straighten up and wait for one second
5. Throttle down

This is all exactly the same hardware as last year, except for the breadboard and the wire connecting the GPS. Last year I failed because the board shook apart. This year I am using a soldered main board. As a result, I have lots of confidence in the software, which wanted to turn, but couldn't because the wire shook loose. I'll start testing actual navigation, gudance, and control next week.

It's really going to work!

This one is even better than the previous steering demonstration. The navigate function is about half complete (it reads and integrates the gyro, it reads but does not integrate the GPS yet). The guide function has yet to be written, but the control function is in place!

I'm worried about it being all on a breadboard and held on with foam tape, but I have some solder breadboards in case it shakes apart in testing. I am still going to use sockets for the Loginator and for the GPS interface, because I am going to want those back.

I still need to think about the "Go" button and the bumper. Watching the replays from last year, it looks like I should do the average G before the start of the race. I turn the controller on, step away from it for a few seconds for it to collect average G, then push the green button when they say go.

Tomorrow early morning I will take the bot to the mall parking lot and drive it manually there, collecting data all the while. I can then use that data to test the guide routine as I develop it. Doing the compass writing on a desktop machine, then porting it to the emulator, worked out well. I am going to do that again with guide().

The current long-range weather forecast is good. I don't want to put a hat on the car if I don't have to.

June 1 Test

When I last entered the AVC in earnest, I remember there being an April 1 test, where you had to demonstrate the vehicle moving and steering under its own power and control. As it happened, I burned out my helicopter and shifted to the car design after this date, but I got a waiver when I demonstrated the car a mere 1 week before the contest. And we all know how that wound up.

April 1 test from last time, completed on April 17

So, I was expecting something like this, this time around. I was watching the Sparkfun web page, expecting to see something there. My phone automatically checks my gmail, so I was watching that. As it turns out, their email got stuck in a spam trap, and I didn't see it until today. So without further ado, I present the June 1 test, completed on February 22, 2014.

This test shows the steering servo connected to an Arduino Nano, powered by the BEC from the ESC, just like the real controller will be used.

Maya wants to help. Some tests are more successful than others...

This test shows the Arduino controlling both the steering and throttle.

Steering is the easy part. It is half of the Control function in the Guidance, Navigation, and Control triad. All the mechanical parts work and if the robot knew where to go, it could control itself and get itself there. The latter is the hard part. I anticipate using a Kalman filter with inputs from the GPS, magnetic compass, and inertial rotation rate sensor. I also am going to add a bumper, so in case it hits anything, it can back up and try again. This is to get around the barrels. I am not currently planning on using the line for line-following robots.

The parts breakdown is about as follows:

Robot chassis - RC car. Includes drive motor, steering servo, battery, ESC, and radio receiver (still carried in robot but disconnected). about $150. Maybe $100 if you count only the parts in the chassis that I actually use, not the receiver, transmitter, or battery charger.
Controller - Kwan Systems Loginator (Logomatic clone) - about $60
Inertial Sensors - Kwan Systems 11DoF - about $40
GPS - GP2106 - about $50
Miscelaneous wires and breadboards - scattered on my workbench.

After last time's debacle, I decided to not go crazy with parts this time. All parts except the chassis are from other projects. I have all these parts already. This is all the hardware I anticipate needing. I use lots of other parts for bench support, such as Arduinos, FTDI chips, oscilliscopes, logic analyzers, computers, etc. None of these are actually part of the robot.

As such, I believe it is a small enough budget that it might fit in the micro class.

As noted in the parts list above, I have chosen to go with the more powerful LPC2148, in the form of the Kwan Systems Loginator. You can read about the design of the Loginator and 11DoF further down this blog. I have repeated all these tests with that controller, but I didn't record them, and they would just look the same as these tests anyway. Video from those tests when it does something more advanced.

Rocketometer has been integrated

The rocketometer is now an integral part of the rocket payload

Attached to the CCD heater card

In the control section card cage

And here we have a short video demonstrating the size of the Rocketometer:

Yukari passes the April 1 test

This thing might actually work...

As I said before, a minor protocol change in the I2C link between the bridge and engine room fixed the little "no B rotor spinning" problem. The bad news is that I got all the parts I needed to build a new engine room, when I don't need them.

I have completed decorating the vehicle (except for signing it, that comes when it's done, probably on AVC day) by putting the official Kwan Systems roundel on the tail fin. I also glued the onboard camera there. I kept looking for a place to stick the camera in the cockpit, and nothing really worked well. So, I attached it to the tail fin. This is a full two feet behind the main body, to give a chase plane feel without a chase plane.

The video below shows the first onboard video taken from this unique viewpoint, during a test of the yaw control on the aircraft.

I need a control loop with a large derivative term on my mood, to control these oscillations. When it works, I feel great, every time I start it up, I scare myself, and when there is any tiny bug, my mood crashes.

Test Flight 5

This is my first proposal as an acceptable April 1 video. It did in fact take off, move forward, turn, and land. I needed to hold it by the tail because the tail rotor part isn't done yet, and for safety.

Test Flight 3

This test is to determine the throttle setting that causes the vehicle to lift off.

This time the throttle was brought up much more slowly, 100ms between steps. Also, the yellow light blinks every 10 steps, so this shows what the throttle level is.

The aircraft lifted off at about throttle setting 145 (of 255).

Test was a complete success!

Test Flight 2

Test Flight 2 included two major changes.

1. A 9V battery is hooked to the Arduino. The choices were either that, or bring a wire across the "Do Not Cross" line on the engine room board. Doing that would expose the Arduino, and the Logomatic, to potential voltage spikes, so that's a no-no. 9V it is. So, now there will be three batteries in the flight setup. One 11.1V rechargable for the main rotors, one 3.7V rechargable for the Bridge, and one 9V disposable for the Engine Room.
2. The program was set to set all rotors to zero explicitly in setup(). I think that this is what really went wrong in Test Flight 1.

Also, the main battery was fully charged.

Test flight 2 was a complete success!

Test Flight 1

Posted on the Sparkfun forum:

I am building a helicopter which is almost certain to win the low altitude competition, except if it is facing another helicopter. I basically just chopped all the electronics out of an existing helicopter, leaving the battery, motors, and airframe. I replaced the electronics with a Logomatic and Arduino-based motor controller, and just got the thing in the air today Unfortunately, it is open-loop and still not controllable, but I still have time, right? Months and months, right?