High Performance 800 degree/s Gyro Project


The photos below are of a prototype high performance helicopter tail gyro based on the Silicon Sensing Systems Ltd CRG20 sensor. This device varient used here supports a maximum pirouette rate of 800 degrees/second and features built in temperature compensation. It also has a fully digital interface implemented as an SPI bus (i.e. no explicit analogue to digital conversion is required).

Most of the required firmware has now been developed by Martin and myself, and we have just started flight testing. This is where we discover if our grasp of DSP, PID control theory and bearing tracking algorithms are actually any good! So far the gyro is working extremely well.

The "flying prototypes" are constructed on a small surface mount PCB - See the photos below. These prototypes are approximately twice the size as a Spartan ds760. Once the design is proven we'll shrink it down by about 60% and house it in a proper case.



We're very excited about this project as it has been a lot of fun to develop, and we are expecting extremely good performance!

Various Gyro Test Videos

Gyro Test Rig #1 (Control loop still work in progress)
First Tentative Flights (Many control loop refinements, still work in progress)
Gyro Test Rig #2 (Acceleration control, various improvements)
Gyro Test Rig #3 (Improved integral term, Now running at the full 800 degrees/s)

First Glow Powered Flight...

This video is of the first flight on an OS37 powered Century Hawk 30. We used this helicopter as it's old/expendable and no longer really flown, as such it has now become our dedicated test machine.

We'd not flown this helicopter for a while, and had forgotten how underpowered and sloppy these old 30 sized helis can be when compared to 50s and 90s. Nevertheless it will make a useful test bed as so far the gyro hasn't been flown on anything that generates any real level of vibration.

The gyro worked extremely well, although it was slightly let down by the twistable torque tube currently fitted to the model. This need replacing with something more rigid as we could hear it winding and unwinding in flight!

Silicon Sensing Systems are also planning to release a 3 axis variant that also features a 3 axis accelerometer, i.e. 6 degrees of freedom. This sounds like a pretty good excuse to build the ultimate flybar-less controller!