AutoQuad ver 5

3689387530?profile=originalI know, the world probably has enough flying machine projects, but here is yet another one.  AutoQuad's original design goal was high precision autonomous flight.  It took five prototypes before I was happy with the hardware.  The current prototype, AQv5, is showing very promising results.  In fact, there is little left to do before this first goal can be checked off  the list.  Using this as a solid base, I intend to continue research, design and experimentation toward vision based navigation for indoor and outdoor use.




- 2" x 2" board with same mounting pattern as the MK FC

- Input voltage ~7.5v => 18v

- High efficiency DC/DC converters

- STM32F103 32bit Cortex M3 microcontroller @72 MHZ

- standard ARM 20 pin JTAG header for real-time debugging

- up to 8 PWM ESC motor control (prefer Turnigy ESC's with custom firmware)

- 2 powered payload servo controllers

- optional ultra sonic range finder

- Spektrum satellite (remote receiver) 2.4Ghz RC radio



- uSD card slot

- optional onboard uBlox LEA-XX module w/battery backup & timepulse capture

- optional female SMA connector for active GPS antenna

- optional external GPS via standard 6 pin connector (EM406, EM401, uBlox, MTK)

- optional onboard xBee module - up to 300mA (2.4Ghz, 900Mhz, bluetooth, etc.)

- optional external radio via standard 6 pin FTDI connector - up to 1A

- I2C bus connector for I2C ESC's


- modular sensor board (SBv5) - 100% analog sensors, EMI hardening:

+ 3 axis acc (ADXL335)

+ 3 axis mag (HMC6042 & HMC1041Z)

+ 3 axis gyro (IDG500 & ISZ500)

+ 2 temperature sensors

+ pressure sensor (MPXH6101A)

+ battery voltage





- Fully threaded RTOS design written in C -  60% idle

- All sensors read at 113KHz (~1.4M sps total)

- 450Hz motor update rate

- 200Hz attitude, 3D velocity / position solutions

- Full downlink telemetry

- Detailed system state dumps @200Hz => uSD card w/FAT32 FS

- Quaternion based attitude filter additionally producing rotation matrix and Euler angle outputs

- All math in single precision floating point

- Temperature compensated and calibrated sensor suite

- Custom ground station software w/bi-directional command and control API

- Cascading PID control system, velocity based for smooth transitions

- Auto land / takeoff

- Hover position / altitude hold

- Autonomous waypoint mission navigation

- Precise altitude hold indoors


Example of current capabilities:


Design philosophy:


- High performance

- Efficiency

- Ease of development

- Consistency / Repeatability

- Low cost


There is always room for improvement.  For instance, I would like to see how much of a benefit using a SPKF (Sigma Point Kalman Filter) would be over my fixed gain navigation filter.  Looking forward to the new Cortex M4 uC's with a hardware FPU so that any such math intensive solution can be more easily handled.  As I mentioned above, there is a lot of room for work with vision navigation and SLAM.  Also interested in propulsion efficiencies which with an eye toward higher endurance.  Although the PID based control system works extremely well, I'm interested in exploring different types of MPC (model predictive control) to reduce control costs and increase precision.


I'm wondering if there is anyone interested in joining forces to work on some of the above mentioned or anything else along these lines that presents itself.  This is only a hobby for me and I currently have no profit motive.  This is definitely not a beginner's project as you can see by my sloppy SMD hand soldering job.



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  • Any news on this project?

  • Hi Mert

    In the rcgroups forum you will find some nice infos:
  • Hello,


    Is there any web site publishing custom firmware for ESC -Turnigy for example- ?



    Mert Turanli

  • Hi Bill,

    I'm interested in testing this board. Can you forward me instructions for a self build or could I donate to the cause in exchange for this board??
  • sorry, i have not read thread!
  • Hello, Please Could you explain this line?

    - 200Hz attitude, 3D velocity / position solutions

    Do you mean you have a velocity and position update at 200hz to do control? INS-GPS?




  • Yes, that is my current thinking. I've just finished the AQv6 design and it has the capability to mount a daughter board which can be used to attach a Gumstix SOC. I doubt you will be able to perform the filter at 200Hz, but you might not need to. You might be able to get away with measurement updates at 5Hz (when GPS data arrives) and some sort of an offline-tuned covariance matrix for the process updates at full speed. We'll see.
  • A faster processor can do the job, such as omap. A gumstix board connected to the flight card can be useful, for example.
  • A UKF will do a much better job. I've written it and can run it on the ground against recorded flight data. It will even bias the acc's & gyro's and correct the orientation solution without magnetometer input. The problem is that it takes too many cycles to run on a uC.


    All of the tunable coefficients reside in the header files that have been published.  However, they will probably not be too useful to you as they are generated via offline simulation based on recorded flight data for a specific machine.  They will have to be recalculated if just about anything is changed in the physical configuration, construction or solution algorithms used by the craft.

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