PIC32Flight Control & dsESC4

Hereby my project, I wanted to build a quadrocopter to learn more about system control and brushless motor and because it is cool. To target also was to make it without as little wires as possible and that is why I made a stacked PCB setup. Made two PCB's one flightcontroller with a lot of possibilities to expand in the future (for instance two PIC32 and also place for MPU-9150). And one PCB with 4 ESC's integrated and battery current measurement, still have to do a lot things (first thing is altitude control). For me it is just a learning experience (programming is not my strongest point). Hope you like it.

Flightcontroller with PIC32

400Hz angle and speed control
2S to 5S
MPU-6050
HMC5883L
MS5611
GPS
SD
Spektrum
Telemetry (Wi.232, will be replaced by RFM22 in the future)
PC control (Labview)
Servo outputs
The possibilty to make bode plots of the quad (looks like this)

dsESC4

dsPIC33FJ
12A per ESC without cooling, (has to be tested more with thermal camera)
2S to 5S
Current limiting
Closeloop RPM
Battery current sensor
I2C
SPI
UART

Todo:

Altitude control
GPS position control
Making it autonomously
Vision control
Camera gimbal
....

He says the calibration is a feature not a bug

http://autoquad.org/wiki/wiki/autoquad-calibrations/

I think that's a big part of the UKF--it helps to automate & refine the calibration & fine tuning of many interdependent parameters. The Madgwick paper goes to lengths to demonstrate a 20% advantage over Kalman filters, but that don't say which one. In my twisted mind that compiles to: compare to UKF or it sucks. The Kalman filter was originally made to fry Americans & Russians I think. That's easily approximated by a linear model. Bots are more like hummingbirds than missiles.

The benchmark Bill@Autoquad states is 15-20cm loiter. That's getting into the range of the uPenn/ETH cheaters with their cameras isn't it? I read somewhere he's seeing something like an order of magnitude increase in this in post processing, which likely can be weaved back into the loop to some degree.

Anyway, that's the best I can do talking out of my ass. There's probably a thread somewhere by those making this stuff with the relevant comparisons. I'll let you know if I come across it.

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J February 18, 2013 at 12:31pm

He says the calibration is a feature not a bug

http://autoquad.org/wiki/wiki/autoquad-calibrations/

I think that's a big part of the UKF--it helps to automate & refine the calibration & fine tuning of many interdependent parameters. The Madgwick paper goes to lengths to demonstrate a 20% advantage over Kalman filters, but that don't say which one. In my twisted mind that compiles to: compare to UKF or it sucks. The Kalman filter was originally made to fry Americans & Russians I think. That's easily approximated by a linear model. Bots are more like hummingbirds than missiles.

The benchmark Bill@Autoquad states is 15-20cm loiter. That's getting into the range of the uPenn/ETH cheaters with their cameras isn't it? I read somewhere he's seeing something like an order of magnitude increase in this in post processing, which likely can be weaved back into the loop to some degree.

Anyway, that's the best I can do talking out of my ass. There's probably a thread somewhere by those making this stuff with the relevant comparisons. I'll let you know if I come across it.
Jeroen van de Mortel February 18, 2013 at 11:32am

Ah oke i didn't know that, it is indeed a very fast computational filter. I'm not that good in mathmatics to fully understand the UKF filters. The autoquad also needs an extended calibration.

But what would be the benefit of the UKF over de descent filter ?
J February 18, 2013 at 10:37am

That's not a Kalman filter, it's a steepest descent filter. It's benefit is that it performs well at low sample rates, but I don't see how that would be helpful in a system with sufficient computational power at the natural frequency. Did you consider the Autoquad UKF? It utilizes many more states within the abilities of the F4.
Jeroen van de Mortel February 18, 2013 at 5:26am

I used a the kalman filter from Sebastian Madgwick (based on Mahony).

http://www.x-io.co.uk/
Michele February 18, 2013 at 5:23am

What did you use to compensate gyro drift?
Jeroen van de Mortel February 18, 2013 at 12:31am

Autoquad uses current sensing to limit the current, that is the same I do.

The website of scolton is very nice, but he uses 2/3 phase current measurement which is needed for FOC, I only measure the bus current.

That UltraESC is very nice
J February 17, 2013 at 1:10pm

This guy has current sensing http://autoquad.org/esc32/

svn checkout http://esc32.googlecode.com/svn/trunk/ esc32

You've probably been here, but for others, Shane Colton has a wealth of information & builds on FOC http://scolton.blogspot.com/p/motor-controllers.html

A very nice DTC build

http://forums.aeva.asn.au/forums/3phase-im-dtc-controller-build_top...

He says the software was a couple of days, most of the work was the high power stuff (for cars).

The guy who made the ultraesc--quickest 6 step, mentioned the possibility of sharing the design.

ESC32

AutoQuad
Jeroen van de Mortel February 17, 2013 at 12:50pm

Yes the motors er driven by six step block commutation, I think you need current sensors for FOC or DTC.
J February 17, 2013 at 11:10am

Inspiring. I take it the ESCs are block commutated... Did you explore FOC (field oriented control) & DTC (direct torque control)?
Mohcine February 17, 2013 at 10:57am

Thank you for sharing, Keep up the great work !

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