im having some problems with throttle in the latest version, there are two problems which might turn out to be two seperate issues, but could quite easily be related.
low-end throttle range just doesnt get low enough, flying in an updraught today (where the slope soarers meet) i couldnt maintain a hover. trying to get the throttle low enough i was actually stopping the motors in flight, the throttle stick was so low my timer wasnt even running most of the time. i also noticed the same problem to a certain extent this afternoon in turbulent but not constant updraught conditions. flying with 400g of camera it was better, but with no load and AUW of 2Kg i need less throttle!
altitude hold in loiter is very unpredictable - every time i go into LOITER the cruise throttle value is very different and the result is usually a climb or descent, ive tried this in very different conditions and it seems only about one in five attempts actually result in altitude hold. position hold in loiter is working well, even in some wind. my first flights with v2.5 had the same tendency, but after a few attempts the throttle trim adjusted to a reasonable value and worked from then onwards.
ive recalibrated my radio, although all the trim values came out exactly the same and theres been no change in the behaviour. ive also just gone through the standard parameters to reset my throttle PIDs to default, they werent very different:
| default | old value | |
| THR_ALT_I | 0,007 | 0,02 |
| THR_ALT_P | 0,5 | 0,65 |
| THR_RATE_P | 0,25 | 0,3 |
is there anything else to look at in config? ive never had alt hold problems before. attached logs, one with attempted loiters in a gentle breeze yesterday, and one trying to hover but climbing with throttle at minimum today.
james
Replies
looking through the changes in source, jason has changed the minimum throttle back to the old value and made these values user configurable.
the only doubt for me is whether or not this is the cause of the alt hold problem in loiter, hopefully ill be able to fly tomorrow and find out.
james
I've adjusted so many parameters that thought a clean install would be in order!
with the previous fw, I thought it was 2.6 but it might have been 2.55 because I installed it using planner mav 0.9 where 1.0 is required with 2.6 ! Anyway with default params I was experiencing:
Very poor yaw reaction
swinging about 50 ft while in Loiter (mag declination on auto)
Agressive throttle.
Now with a fresh 2.6 install:
Moderate yaw reaction, but still too mild
Loiter Mode= much less swinging around (mag declination now on manual) & windy
Now needs a boot full of throttle when going into Alt Hold and Loiter or it will drop like a stone( this is new, about 1/4 travel increase in throttle required) with a corresponding decrease in throttle required when switching back to stabilize.
Also noticed that props start turning the moment the throttle is off the min stop. i mean like a thou or two off the end stop and the props are turning, disconcerting!
Just for the record, when setting the Tx travels up, are you supposed to do this with throttle trim at minimum or mid setting? I have always used minimum in the belief that the flashed esc's require a very low throttle setting to initiate.
I think max and min throttle values should be an adjustable parameter. Can that be added in the next release ?
ok i found the change by jason defining new max and min throttle values in config.h, where before we had:
# define MINIMUM_THROTTLE 130
and now this is defined as 200. i will change mine to 150 which i expect should help at least with the first point, though i dont know if its going to help with loiter.
james