The distributors finally got in some of the new ST Micro STM32F2 series uControllers and I grabbed a few. I was able to "shoehorn" one into a ver5 board as the pinout is close to compatible with the performance STM32F1 series. Spent a few days rewriting the device drivers and am very impressed with this controller's performance.
I was able to bump up the sample rate to around 276.8KHz for all 12 sensors for a total of ~3.32 million samples per second. Despite this more than doubling of work load, I ended up with around 70% idle time, up from 60% of the STM32F1. Keep in mind that at a 120MHz clock rate, this 70% free cycles represents more than twice as much free number crunching capability than the STM32F1 at 60% idle. I also found that the DMA to be much better with full FIFO available on each DMA channel and an easier to use triple ADC.
The result is a much cleaner interpretation of the sensor data which translates to a smoother and more stable platform.
Comments
Wim: Turnigy hardware, modified firmware
Patrick: I'll detail the V6 change in a new post once they are finalized
srinath: I try to avoid Matlab as it is slow. All of my testing and filter code is done in straight C using libraries that I have developed over time. If find that for maximum performance, a UKF needs to be properly tuned which can sometimes be difficult. PM me for more info.
Ludovico: Flight tests are conducted at a top secret testing facility somewhere in the eastern US :) Actually it is an ideal place as it is slightly GPS deprived due to surrounding mountains and the wind is generally unpredictable - keeps you on your toes.
Awesome job, and BTW, were was this video taken? the landscape and free space looks awesome 0.0
I am interested in joining this project. I want to contribute to the state estimator design and improving the control law.
I typically implement all the state-estimators as S-Functions in Simulink, before porting it on board. Is this how you do it? I currently have an EKF for ins-gps integration, my UKF seems to perform only on par with the EKF.
Very impressive. I know for myself that it is hard to get a good GPS Performance. But yours is really good.
I will try to build one of you boards. How many layers do you use.
Regards
Patrick