RCTP V2 build pictures

TCTP V1 pre retirement flights

RCTP Mk II parts

Made some new parts today for an updated test platform. The new device has with slightly larger control surfaces and some of the more annoying mounting issues has (hopefully) been resolved.

RCTP 1. tethered test

Since only a small test space was available the RCTP was teathered. Most of the time the teather was slack and thus not affecting the flight.

Videos of tuning process

Here is a video of parts of the tuning process.

More RCTP tuning goodness

After the unfortunate propeller-meeting-flesh-incident i have decided that the RCTP needs to be tuned without touching it.

 Adding a gimbal around it's center of gravity let me tune pitch and roll individually.
All data are in and the RCTP should now be stable on all axes.

Pitch response

AND NO BLOOD!!!

Pitch and roll tuning end in pain...

After the initial success i went on to tuning the PID controllers for pitch and yaw. After 20 fairly sucessfull minutes i accidently hit the throttle while holding on to the elastic ribbon and WHACK ... the rotor cut deeply into two of my fingers sending blood everywhere.
Bad times. Experiment now suspended until i have all my digits back...

Moments of robot tuning

After completeing the RCTP hardware the flight controller needed to be adjusted for stability. I am using a simple PID controller for now.
Starting with YAW I suspended the RCTP from an elastic ribbon so that it was able to yaw freely.

Throttle and YAW tuning parameters was supplied from the RC-controller via wirerless. Measurement data was received via. cable.

I chose some conservative initial settings for the PID controller (Blue: Integral=0, Green: Proportional=30, Yellow: Derivative=35-ish). And commanded (via the RC controller) a yaw angle of 0.
When starting the rotor the system was oscillating around the YAW axis as suspected. Increasing the D-term (again via. a slider on the RC controller) cancelled the oscillation. A push on the RCTP confirmed that the regulation loop worked.

After some testing it was confirmed that the YAW angle of the RCTP was not zero (zero angle is currently the compass angle in which the flight contrroller is power up). Increasing the I-term fixed that problem.
Yaw is now stable regardless of the rotor speed.

RCTP roll cage and progress

After a stupid accident I decided to protect the propeller of the Reaction Control Test Platform.

Using 1mm. carbon rods I made a cage that surrounds the propeller. The cage only add 4,9 gram to the structure but is still very strong should easily keep stuff out of the blades.

Total weight now 295,4 gram.

After completing a preliminary firmware for the device I have now flown it a couple of times.

As expected it has a tendency to wobble. This is caused by the gyroscopic force of the propeller. I have designed the firmware so that i can offset the angle between the IMU  thrust vectoring vanes. This should allow me to compensate for these forces.

Right now the flight controller is loaded with a conservative set of control parameters but still seems fairly stable. Over the next couple of days i will be optimizing the system and have more flight testing.

Firmware

Hardware

Reaction Control Test Platform

RTF ~320 g.

~600g of thrust.

Power controller and LiPo battery.

IMU, data logging memory and controller board.

This device allow development of flight routines and control algorithms without the need for actual reaction engines.