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About this blog

I am working on a Digital Flight Control System (DFCS) for my UFO foiler.  In this space, I plan to share my design as I progress with it.

SD_Foiling_Close_Up_Resized.jpg

Entries in this blog

Test Flight 2

Finally real success!  I got back out there this week with a fully waterproofed servo, an added lidar sensor and a major code overhaul based on Test Flight 1's test data.  Observations were: 1) Pitch control is now much better.  While I still think the control loops could be better tuned, I am now getting long runs with very good pitch stability and no more porposing as you get with the wand-based systems.  In lighter air, I suspect that the lack of paddle / wand drag will allow me to fly m

DerekF

DerekF

First Flight

I got out Monday for a first flight for my digital flight control system.  Overall it was a big success!  The one thing I cut corners on to get out there was fully waterproofing the servo.  I felt that the likelihood of a turtle capsize was low (my last one was months ago).  Of course, what did I do after 90 minutes out there?  Turtled the boat and killed the servo--HAHA!  But still a great day with lots of learning and successes:   1) Being able to "arm" the system at the press of a button

DerekF

DerekF

Servo Actuating Flap with Torque to Spare!

Electronics module and servo now fully mounted on spirit and actuating the flap with torque to spare!  First flight in mid June is on track!  Last steps are some linkage adjustments and test tank time (in my hot tub)!    

DerekF

DerekF

Almost There!

See the linkage working with the servo and altimeter to control the bell cranks and foil flap.  First flight should be sometime in June!    

DerekF

DerekF

Integration, Data Crunching, and Mechanical Integration

Another update from the land of digital flight control systems! Integration I now have all sensors talking to the Grand Central board and the algorithms (PID loop, ultrasonic sensor filter and smoothing, etc.) performing as designed.  The wireless remote is also working and allowing the user to adjust PID Parameters, Altitude Setpoint, and Smoothing coefficients.  The LCD is putting out status messages and feedback when the user is changing parameters.  I am also collecting all the data f

DerekF

DerekF

PCB's!

Good news!  I just received PCBs back from the fab house and all parts fit.  This simply means I know how to be very detail-oriented with a pair of calipers and my CAD software.  I mentioned in a previous post that mounting all of the modules to a single PCB was easier and more electrically sound than using a "base plate and flying wire" approach.  The PCBs are back and everything fits mechanically.  As you can see from the photo, I have added 0805 inline footprints on every trace.  The ide

DerekF

DerekF

Servos and Battery Sizing

A few more updates on the project with the selection of a servo and battery. Servo Sizing: I decided to actually measured the torque required to actuate the flap.  I did my measurement out of the water and therefore I only measured the resistance of the linkage and the resistance of the rubber "spring" that mates the foil flap to the mainfoil.  I did the measurement using a pull scale attached to the wand 6 inches from the pivot point of the wand.  I found the required torque to be ~32

DerekF

DerekF

Data Logging, Wireless Control, and Enclosures

Time for another blog installment of the Digital Flight Control System for my UFO.  I have been busy at work on the project and making good progress toward a first flight in early 2020!  Also attached is an updated block diagram with details on various subjects below:   Data Logging: In my last blog post I mentioned that we needed some sort of data logging to really get into the meat of how well our control and filter algorithms are working.  Post processing data after getting off

DerekF

DerekF

Sonar Range Sensor Test in Turbulent Water

With much of the code and working and sensors talking to my Arduino board, it was time for some real world testing this past weekend.  I always try to find as much information online regarding sensor characteristics or what has worked for others, but at some point there is no substitute for empirical data.  At the heart of the feedback loop is our ability to measure altitude.  We will be measuring altitude with a waterproof sonar sensor similar to those used in automotive bumpers.  There is

DerekF

DerekF

Sensor Integration, Code Success, and Servo Math

Another quick update, A productive weekend ended up with an IMU (BNO055) and a waterproof sonar range sensor (JSN-SR04T) being integrated to my Arduino Mega board.  Both are yielding good data and easy to work with.  I also am able to write commands successfully to a spare servo I from an RC Tricopter.  I am still in the process of selecting the correct servo and identifying the correct attachment point(s) for the servo to flap linkage (please see and comment on servo math below).   Ad

DerekF

DerekF

Initial Thoughts, Philosophy, and Block Diagram

Ok team, here goes my first blog post.  My goal here is to build a Digital Flight Control System (DFCS) for my UFO using a sonar range sensor as opposed to the wand.  The design needs to completely mimic the performance of the wand system currently in the boat.  The system needs to be fully removable to allow for One Design Racing if desired.   A few design guidelines... Improvements to current control system: 1) Sensing wave terrain out ahead of the boat 2) Not engaging the

DerekF

DerekF

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