How to implement compound heli boost control into velocity command and auto flight modes?

bnsgeyer · November 26, 2017, 4:00pm

I have already created the motors library that handles the electronic mixing in this PR

github.com/ArduPilot/ardupilot

Compound Heli Support for Copter

ArduPilot:master ← bnsgeyer:compound_heli_pr

opened 05:36AM - 22 Nov 17 UTC

bnsgeyer

+971 -2

Development Team, As some of you may know I have been developing a compound hel…i that I've named the X3 after the eurocopter (now Airbus) manned helicopter. My initial code development was on Copter 3.3.3 closely following the @fhedberg repository. I've been flying my compound helicopter for almost 2 years now with a pixhawk. Initially I used the straight tradheli firmware and passed through the boost control on channel 7 and used mechanical mixing to mix the boost and yaw control. Recently, I finally put the code that I developed on AC 3.3.3 to use with independent servos driving each propeller. The link is a video of the X3 flying. [https://www.youtube.com/watch?v=kRpDxFRXIoM](url) So with the recent incorporation of the Dual Heli frame, I got inspired to pull the compound heli frame into Copter 3.5. With the new motors class/frame framework, it was fairly easy to incorporate the compound heli frame as a class within tradheli, especially being able to follow the PR that @tridge did for the dual heli. The biggest challenge of this vehicle is the requirement for a fifth control input for the boost. At this point, I've limited the use of this frame to mainly manual modes like stabilize, acro, and althold. All of the flight modes where the pilot controls speed rather than attitude, I've disabled until I'm able to come up with a suitable implementation for the controller. However I would like to have the development team, review my commits for the compound heli implementation and provide feedback before I look to PR for incorporation into master. I was hoping to get this into master and then continue making improvements to how the flight modes use the boost control.

I hadn’t thought about this but I had already created a motors library for compound Heli for AC 3.3.3. So I built the 3.5 version based on that one.

So in my AC3.3.3 version I didn’t have anything like this. It was straight control input mixed to symmetric thrust output. I was considering in loiter or auto mode to have pitch and thrusters mixed where the thruster would be lagged to provide more of the trim or average acceleration and the pitch attitude changes would provide the more instantaneous changes. However I think the thrusters would be responsive enough to handle this without requiring pitch changes. This is something I have to look at.