Testing new controllers PX4 autopilot

Pixhawk
1

Hello @bresch ,
I am working to implement different controllers other than PID and want to test on PX4 autopilot in SITL.

Can you please guide me where do i need to make changes in the firmware stack to test a new controller?
thanks

2

Hi @Ranjeet. This might be a good place to start looking:

3

Hi @benasena @bresch , I have gone through the current PID controller that works at 4 levels (attitude rate, attitude, velocity and position). And, I can see that mc_att_control, mc_pos_control and mc_rate_control are modules that deal with controller implemented.

Like, Suppose I just want to implement a position controller (say sliding mode controller), then many parameters (PID gains) will not be required and few parameters has to be added.
I was thinking of testing different controllers in PX4_sitl. I am aware that i need to write a module for another controller but what communications are going on among other modules and the present controller, if there is some picture, then that would be great.

4

You can probably take a look at this uorb graph to get an idea of message passing between the modules. Do note that some of the topic names maybe changed for the most-updated version.
https://dev.px4.io/v1.10_noredirect/en/middleware/uorb_graph.html

5

Hello @Ranjeet
According to the Multicopter Control Architecture the Position and Velocity Controller Diagram are a mix of P (for position) and PID(for velocity).

I was trying to add a PI/PD/PID controller module instead of the P controller for Position?
I note the following codes (mc_pos_control module) have the controllers.
I wanted to know if there are other places to be modified for the different types of controllers based on your work. Thank you in anticipation!