Discussions

Fly_By_Wire_Rates

Posted by Matthew Epperson on August 29, 2014 at 12:39pm

Hi Everyone,

I've been working on trying to meld two different modes together Fly_By_Wire_B and ACRO mode inside ArduPlane. The basic idea is that I want to use the TECS controller to keep the plane at a desired altitude and airspeed, kind of like what FBWB does, while being able to pass rate commands to the plane using a mavlink message.

At the moment I can pass a yaw rate command to the plane and do the back calculations based on velocity and yaw rate needed to find the roll angle. It works fairly well so far, however, its important to note that I am sending the mavlink message with the yaw rate from a computer that lives onboard the plane.

I'm looking for any suggestions or references to other people that may have already done something similiar to this.

-Matt

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Replies

Matthew Epperson September 5, 2014 at 5:38pm

Updated post along with video of swarming

https://groups.google.com/forum/m/#!topic/drones-discuss/eGms8PIQerw

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Matthew Epperson September 2, 2014 at 4:45pm

I'm using this for with multiple UAVs. A few algorithms like flocking are more suited to turn rate commands than waypoint navigation. The other computer keeps track of the states of the other planes in the flock.

Nothing wrong with pixhawk or l1 just need something more specific.
- iskess > Matthew Epperson September 5, 2014 at 4:36pm
  
  Very cool! Way beyond my knowledge base. I'll be watching with interest.
iskess September 2, 2014 at 3:19pm

What's wrong with the Pixhawk L1 controller. It works very well. I'm sorry I still can't understand why you need another onboard computer. What can it do that the pixhawk can not?
Matthew Epperson September 2, 2014 at 9:47am

For further clarification right now I am using this mode for turn rate commands.

An example being the payload has a goal location which is simple a gps waypoint. The payload then calculates the error between the planes heading direction and the direction towards the goal and used a PID controller to calculate a desired turn rate (yaw rate). It sends this the plane over a mavlink message and the autopilot interprets this and preforms the necessary actions to turn at the rate specified.
iskess August 29, 2014 at 4:23pm

Please describe some useful applications of this hybrid mode.
I'm not following.
Thank you.
- Matthew Epperson > iskess August 29, 2014 at 5:36pm
  
  Right now autonomous flight is restricted to the use of the L1 controller and waypoints. The idea is to provide the ability for high level path planning to be done off board, in my case, a payload computer and then pass rate based commands to the plane via mavlink. I'm using this for potential fields at the moment and I don’t really want to worry about keeping my height and speed hence the use of the TECS controller.