|
|
|
|
||
|
United States
Joined Feb 2001
16,170 Posts
|
Quote:
|
|
|
||
|
|
|
|
Great White North
Joined Jun 2008
621 Posts
|
report - quad using open pilot coptercontrol
Folks
Just finished intial test. My comparisons are my mikrokopter and the same openpilot coptercontrol flying with dys unmodified 30 amp ESCs my setup 400mm MK frame 4 750kv DYS 28-30/14 (not the best motors but thats what I have on hand) openpilot coptercontol board - output set to 400hz 4 25amp castle phoenix - firmware v4 - set to multirotor - all default firmware settings with regards to motor timing and rates etc result = unfortunately not good ![]() 1) you have to set PIDs to at least 1/3 of what they were with DYS otherwise it would oscilate itself out of the air. 2) even at that setting, the control input was sluggish?? 3) I could get it to hover in stabilized mode nicely with 1/3 p value compared to DYS, but it was like flying through honey - sluggish like hell 4) in rate mode, I could not find a p value that would allow the quad to hold position without it oscillating out of the air. that means if I used a lower p value - I could not control it - increasing the p value a bit would give me control but it would oscillate and be uncontrollable that way. I mostly tried to get a stable rate mode - using p and setting I to zero, but was unsuccessful. So I tried a few combinations of lower p values and increasing I values - but still no joy. The weird thing is the oscillations were slow even in rate mode. raising rate p is supposed to create rapid oscillation - but it did not!! It was like the output rate was way too slow. Without trying to sound argumentative or disrespectful to CC. There is no way that the output rate can change the throttle from 0 to 100% 50x per second with this firmware. The output rate is slow. Unfortunately my only control board is my MK and Steve's copter control. I do have an arducopter, but I don't trust it at all and given the copter control was completely adjustable and flyable using 15$ DYS ESC, the problem is clearly the castle ESCs or the current firmware (sorry )I have to step out for a while - but if any of you have some suggested setting or firmware settings - I would be happy to test out your suggestions and report back (including any suggestions from the castle folks). Thanks Al |
|
|
|
|
||
|
Great White North
Joined Jun 2008
621 Posts
|
Quote:
but it was set to 400 with the DYS Escs Al |
|
|
|
||
|
|
Quote:
Thanks for your detailed report! I really wish that you had experienced different results. It now appears that we had similar findings on both the WK-M and the Copter Control platforms. It was my feeling as well that the output rate of the Phoenix ESC’s was just not fast enough to keep up with the commands from the Flight Control Systems. Of course this is just the opposite of what Patrick stated earlier, “Perhaps we are changing the output rate TOO FAST, which results in instability”, but it sure didn’t SEEM that way during testing. Of course I’m not an engineer so it is only speculation at this point. In regard to changing the output rates as RC Man is suggesting, “50, 100, 150 and 200 Hz”, that would have to be done in an FC (if the one your testing is even capable) since there is no provision for that in the current CC Multi-rotor firmware. In the multi-rotor firmware, about the closest that you can get is being able to change the Motor Timing from LOW to NORMAL to HIGH and selectable PWM Rates of 8,12,16 & 24, none of which made much of a difference in my testing. I would really like to know which platforms Castle Creation had the multi-rotor firmware working so well on prior to its release and why it worked on them and not on ours. Tom |
|
|
||
|
|
|
|
United States, TX, San Antonio
Joined Feb 2007
12,782 Posts
|
Gents,
If you have to lower the flight controller's proportional value when using the CC ESCs, then they do not have as good an update rate, or they have some other "smoothing" going on that causes this. ESCs that have linear response and high update rates allow for a higher P setting. See this post for an excellent way to test and find out if the ESCs can respond to rapid input/output: --Testing ESC update responsiveness: http://www.rcgroups.com/forums/showp...55&postcount=9 Cheers, Jim Quadrocopter and Tricopter Info Mega Link Index |
|
|
|
|
||
|
United States
Joined Feb 2001
16,170 Posts
|
Quote:
My thinking was that if you try to change the motor speed much faster than I can react that you have a situation where you are over controlling it making for instability. I just thought that if you controlled the motor closer to it’s actual response speed that the entire system would work much better. If the motor can only respond at 50 Hz I don’t see how truing to control it faster than that is going to cause anything but trouble. The controller is just going to keep cranking up the values but nothing will happen for several frames and by that time the value will not be what you want causing continuous overshoots and loss of stability. It’s been way too many years since I had a control system theory class. Maybe someone could find a timing diagram that would help to clarify this. The way that helicopter rudder gyros and servos solve that problem is they have very low inertia motors that respond at over 500 Hz. Multi rotors are the opposite as they have relative high inertia outrunners turning large slow turning props. Do we have any Engineers on this forum that are control system theory experts? Hopefully CC has one working for them – if not we are all in big trouble – LOL.
|
|
|
||
|
|
|
|
|
faster = better
and it does not really matter how fast the prop reacts it matters if thee is smoothing etc... where is that darn post where someone tests a bunch of esc's with a computer scope and shows the esc output response???? CC needs to send us some esc's to their firmware on cause I sure aint buying them if they think this firmare is the best ever created as claimed ![]() Steve |
|
|
|
|
||
|
United States, TX, San Antonio
Joined Feb 2007
12,782 Posts
|
Steve and RC,
Here is KapteinKuk's ESC response thread: http://www.rcgroups.com/forums/showthread.php?t=1250488 Cheers, Jim Quadrocopter and Tricopter Info Mega Link Index Quote:
|
|
|
||
|
|
||
|
Great White North
Joined Jun 2008
621 Posts
|
Quote:
I will quickly try changing the output rate and report back Al |
|
|
||
|
| Thread Tools | |
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Sold NIP Castle Creations Phoenix 25 ESC $38 | phoneguy | Aircraft - Electric - Power Systems (FS/W) | 1 | Jan 20, 2012 09:12 PM |
| Sold E-Flite Power 60 - Castle Creations Phoenix 80 ESC - Castle Creations 10 amp BEC | moxjett | Aircraft - Electric - Power Systems (FS/W) | 6 | Oct 18, 2011 08:49 PM |
| Sold Castle Creations Phoenix-25 Brushless ESC | 5478Jimmy | Aircraft - Electric - Power Systems (FS/W) | 3 | Sep 19, 2011 08:02 PM |
| Sold Two new Castle creations ESC's in package - Phoenix 45 and phoenix 25 | GyroRon | Aircraft - Electric - Power Systems (FS/W) | 10 | Aug 19, 2007 11:07 AM |
| For Sale Phoenix Castle creations ESC 25's and 35's brushless | stealthy | Aircraft - Electric - Power Systems (FS/W) | 11 | Mar 21, 2007 06:27 PM |