Quadrotor Digital PID Control System and Dynamics Modelling


A digital control system model of the pixhawk quadrotor was constructed in scicoslab along with a continuous model of the quadrotor dynamics (the visual model is an arducopter). The user can input the guidance commands to the autopilot through sliders. As the video shows, the yaw response it not optimal, which also happens in the actual system. Using the mavsim Scicoslab toolbox (https://github.com/openmav/mavsim/) , the model can be simulated and then, once the system has been correctly identified, the dynamics can be linearized. The linear model of the system makes the problematic modes clear and aids in designing an improved controller.

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Comment by Birdeye on March 19, 2011 at 3:36am
Cool Project.

http://birdeye.dk
Comment by Hyon Lim on March 19, 2011 at 3:54am

Hi UFO-MAN.

Yes. That paper is right. But you should note that the paper does not include about MPC.

The reason why I recommend that paper is to experiment various control algorithm.

Comment by Kostas Alexis on March 19, 2011 at 4:38am

@ Hyon_Lim

I have experimentally implemented MPC in Quadrotors. You are right about the computational complexity but this is something that can be accomplished using model embedded CPUs. 

 

@ James Goppert

I'll send you some articles on the topic of optimal parameter selection. Give me one day to collect. 


Developer
Comment by James Goppert on March 19, 2011 at 12:28pm
@ UFO-MAN, a virtual machine running the latest ubuntu or debian release is your best bet right now. We have mac almost working on cmake and mingw version for windows could be possible if we get some more interest.
Comment by UFO-MAN on March 19, 2011 at 12:59pm

Hi James.

 

I have been installing just that since my posting earlier today :)  I installed Ubuntu on Virtual Box and is in the process of installing Flightgear with Synaptic now. I will have to evaluate the performance, as it looks a bit (ehh. very...) slow. However so far the install procedure looks like its flying.


Developer
Comment by James Goppert on March 19, 2011 at 1:19pm
@ UFO-MAN good luck, make sure you have your graphics card enabled in virtual box. If you get something that works well let me know and I will host a virtual-box for mavsim. Mavsim will work without flightgear and will allow flightgear to run non-realtime via the external fdm protocol (jsbsimcomm block), so the speed shouldn't be critical, but annoying. Worst case you could dual boot :-).
Comment by UFO-MAN on March 19, 2011 at 1:26pm

Yo!

 

Flightgear seems like it sux a bit in terms of execution speed under Vbox. Even with 3D acceleration enabled.

 

Perhaps it's better to run Flightgear under native XP so it has direct access to the graphics hw. Then the Mavsim stuff could run on the VM. I may try that.

 

ufo

Comment by UFO-MAN on March 19, 2011 at 1:27pm
By the way, can the link between Mavsim and Flightgear be run on a TCP/IP socket? Isn't that the way it operates anyway? If it is the idea in the last post should work. I could even run Flightgear on another box here.

Developer
Comment by James Goppert on March 19, 2011 at 1:40pm
I am using a udp instead of tcp/ip, but yes. The socket communication can talk to any host. If you click on the jsbsimcomm block you can specify hostname:port. So as long as it doesn't have trouble going through the vbox it should work. I run flightgear on other workstations in our network all the time. To setup flightgear for this type of communication you can take a look at the script in mavsim/scripts/fgrunExt.sh. You should be able to setup most of that in your flight gear configuration file.
Comment by UFO-MAN on March 19, 2011 at 1:43pm

Aha ...  then I should be able to get this flying over UDP/IP!

 

Will report back later.

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