ACRO bug (fixed in 2.9.1b): while doing flips in ACRO mode, if you switch to Stabilize while inverted your throttle will go to minimum. To regain throttle control you need to switch back to ACRO then back to Stabilize again (i.e. switch to stabilize twice). You never lose control of roll/pitch/yaw.
Loiter/AltHold/Auto/RTL bug: if you switch into these modes with throttle at zero motors will go to minimum until you raise the throttle.
Auto mode altitude bug (fixed in 2.9.1b): setting a waypoint altitude greater than 320m over home altitude may wrap around and instead be interpreted as a low altitude.
ArduCopter 2.9 is now in the mission planner and the downloads area!
The major improvement is we use inertial navigation to improve altitude hold. This increased reliance on the accelerometers means you must do some additional set-up before flying:
3. If upgrading from 2.8.1, modify the throttle and altitude PID values:
Here is the list of major changes (a more detailed list can be found in the release notes):
As per usual PIDs are optimised for the 3DR/jDrones quad with 850 motors and 10" props. If you're using more powerful motors/props and are seeing bad flight behaviour in stabilize, start by turning down Rate Roll P in 25% steps.
Special thanks to our testing team lead Marco and the dedicated bunch on the 2.8.1 release thread who put their copters at risk while testing the pre-release version. Some of their videos are here: 1 2 3 4 5 6 7 8
Please feel free to report issues you find in the discussion below and/or add them to the issues list.
I think we've found that it's actually better at 20. It gets rid of some more noise and it's still fast enough that people don't notice any lagginess. We're actually going to make the default 20 for the next release (currently the default "0" = "42").
Darn, I missed KevinB's post that it wasn't working during the testing period. I'l have to look at it again for 2.9.2.
By the way, there is a new parameter called YAW_OVR_BEHAVE which controls when the autopilot retakes back yaw control after an override (normally a pilot override). The default is "0" meaning at the next waypoint but you can set it to "1" and then it should never retake control until you restart the mission.
Congrats on your flight!
In stabilize mode the pilot is 100% in control of the throttle so you'll be doing the altitude hold yourself. It sounds like your copter has a lot of power if it can hover at 20% thorttle..maybe you should put a bigger battery on it to at least get it to 35% ~ 40%. It's not a huge deal but when you start using flight modes with altitude hold built-in (ALTHOLD, LOITER, AUTO) the copter will tend to sink or climb as you transition because your stick won't be in the right position for the mode you're switching into (because the deadband for the auto modes is from 40% ~ 60% of throttle).
In anycase, good stuff. For safety's sake you should check your accelerometer values before trying alt-hold.
Thanks for the info Randy. I'll try Y.O.B.=1 and ROI next time out. If it works, I'd like to see yaw override as a ch7 option in 2.9.2. :)
Thank Randy for your support. one more thing if i enable the Alt-hold but without using Sonar it will climb until it reach at leass 10 meter? or it will do nothing?
what value should i get for the accelerometer before i try the alt-hold?
It uses the barometer + accelerometers for alt hold in genearl so it works fine without a sonar. No climbing to 10m or anything like that. In fact, in many ways alt-hold works better without a sonar.
See all the graphs that people are posting in this thread? They're all checking that their Z accelerometer value in particular is not bouncing outside of -5 to -15. That's the key to good alt-hold. Lower vibration the better. Also remember to set the INS_MPU6K_FILTER to 20.
In this case I won't change the throttle setup, becuse in stabilized mode it flies very well.
I'm running my quadcopter with an APM 2.5 board, an uBlox GPS unit an external magnetometer and firmware version.
My external magnetometer is placed with the components down and pins facing forward.
Can I use the standard pre-compiled firmware or do I have to compile a specific version, because I'm using an external magnetometer?
You can't just flip your compass so it's components up, pins forward?
It not then you'll need to add a line like this to your APM_Config.h:
#define MAG_ORIENTATION AP_COMPASS_COMPONENTS_DOWN_PINS_FORWARD
Please note that if you're compiling your own firmware based on 2.9.1 you all need to ensure this line is in your APM_Config.h:
#define CONFIG_APM_HARDWARE APM_HARDWARE_APM2
So just to be sure. If I mount my external magnetometer with the components up and pins forward there is no need to compile the firmware and I can use standard firmware?
i will try to figure out the Z value , does the alt-hold work below 10m without using sonar?
Yup, that's right. Then it will match with the orientation of the compass on the APM2.x boards and you can use the standard firmware.