Changing Control Allocation

Hi everyone,

I have had my octorotor flying using the 2.7 version of the code and everything is going well.

I would now like to change the reference frame of the vehicle so that it is valid on a global frame. This means that regardless of the vehicle attitude from where I am standing, if I want it to fly to my left I use the control stick to point to the left and it goes that way even if it means that the vehicle is pitching instead of rolling.

I have gone through the code as well as I can and found a line that says motor_to_channel_map. (this is in line 189 of AP_MotorsMatrix.cpp) and then line 39 of AP_Motors.cpp states:

// initialise motor map
    if( APM_version == AP_MOTORS_APM1 ) {
        set_motor_to_channel_map(APM1_MOTOR_TO_CHANNEL_MAP);
    } else {
        set_motor_to_channel_map(APM2_MOTOR_TO_CHANNEL_MAP);
    }

Can anyone please help me to find where this mapping is taking place?

This will be the basis for applying some university research into control allocation so that I can perform motor failure flight testing.

Thanks for any help.

Aryeh

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DeveloperPermalink Reply by jasonshort on September 7, 2012 at 5:01am
Simple mode remaps the user input based on yaw. Does that help?
It's a simple vector rotation. It's far more upstream than what your talking about.
Permalink Reply by Aryeh Marks on September 12, 2012 at 9:33am

Thanks for that reply, but this is to do with a more ambitious plan for using a pseudo-inverse method to determine control allocation (I've written a paper on the theory of it and now I've got to put it in to practise!).

For example, I've got a switch that cuts the power to one of the motors. The vehicle should reconfigure the voltage demands between the remaining 7 motors to perform exactly the same as when there are 8 motors (up to a point, obviously since there is less total thrust).

As it is, if a motor fails then the vehicle drops altitude and rolls towards the broken motor...

Thanks

Aryeh

Permalink Reply by Yangbo Long on February 20, 2013 at 11:46am

How is your control allocation going on? Did you implement the pseudo inverse method onboard?

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