Feiyu victory

The answer is yes. Multivariable calculus works & the handle angle can be derived from the motor positions. The lookup table for the angle ended up precise to 5 deg while only taking 170 bytes. It's vastly simpler than a 2nd IMU, but requires volume manufacturing to be cost effective. It's a very sloppy result, because the mechanics in the motors are sloppy & the hall effect sensors are sloppy.


This led to a nasty gain schedule of PID constants to handle the motor mixing. It barely worked. The decision was made to make assumptions about the motor mixing instead of relying on the PID controllers to hunt for a result, as had been done for 4 years. The ratio of roll & pitch motor steps would be hard coded for every handle angle. A small math test program showed this would follow a simple sine wave pattern.


The hard coded motor mixing worked quite well. It didn't need a gain schedule. It was rock solid & better than the factory settings. It was surprising how simple controlling the gimbal was, but also what a high level of multivariable calculus the Chinese were applying to forgettable consumer products.


Adding variable pitch would be a matter of multiplying the IMU result by a similar motor mixing formula. The gyro rates would also have to be mixed. It's such a pain to avoid bumping the pitch on the joystick, it would require replacing the joystick with tact buttons or providing another switch to lock the pitch. Joysticks are bulky, but they never point the camera the wrong way because of hitting the wrong button. The leading idea is a pair of tact buttons in addition to the joystick. Variable pitch has never been used, but perhaps it might be used for an interior space.


The other feature would be working upside down. The mane problem is detecting when the user wants to flip it over. It would have to detect when the roll exceeds a limit & when it initializes upside down. This too has never been used. The next priority would be working upside down to get vehicles in frame.


No action cam footage has looked good besides eye level footage locked in position, but variable pitch & working upside down could come up exactly once in a lifetime. There's a reason action cams are normally locked to a vehicle rather than being pitched up & down.