I thought you guys might find this interesting. Support for OneShot ESCs was recently written for Tau Labs (http://taulabs.org) and it seems like most of the claims that it is good are largely subjective (which is perfectly fine). However, I wanted to really test the performance improvement with this different pulse scheme.

Here you can see the latency from an update from the gyro (MPU9250 IRQ) to the completion of the pulse is about 300 µs, which is much better than the several milliseconds with traditional asynchronous PWM.


I used our autotuning algorithm which estimates the system properties like the reaction speed of the ESCs on the same quad before and after engaging One Shot mode. The end result is a significant improvement in ESC latency as shown above. 
The results are statistically significant. Since the ESC latency is the prime performance bottleneck for quadcopters, this improvement will allow tighter PIDs and higher bandwidth control. That is the result of the autotuning algorithm - higher PID settings with OneShot than without.


For the longer writeup see here http://buildandcrash.blogspot.com/2015/01/oneshot125-quantitative-t...

Views: 1839

Comment by Ben on February 1, 2015 at 11:14am

Great job, 20% reduction in reaction times is awesome!

Comment by titeuf007 on February 1, 2015 at 12:14pm

i hope we could see this option in a near futur for arducopter

Comment by Matthias Badaire on February 1, 2015 at 12:45pm

MR60
Comment by Hugues on February 1, 2015 at 1:53pm

This is chinese to me without getting a minimum of contextual information. never heard of one shot esc. Sounds like a disposable esc you use one shot :p


Distributor
Comment by RC Tech.se on February 1, 2015 at 11:54pm

 @ Hugues: It provides a faster update to the ESC and hence better control of the ESC/aircraft craft.

Comment by Tobias Witting on February 2, 2015 at 3:38am

this video shows a direct comparison of PWM and Oneshot: https://www.youtube.com/watch?v=b1BX3TDD28g

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