Warning #1: Compass calibration and reducing interference is far more important than with 2.9.1b
Warning #2: GPS glitches can cause sudden and aggressive position changes while in loiter mode. You may wish to reduce the Loiter PID P to 0.5 (from 1.0) to reduce aggressiveness (see image below of where this gain can be found in mission planner).
Warning #3: optical flow is not supported but will be back in the next release (AC-3.0.2 or AC-3.1.0).
Warning #4: loiter turns does not maintain altitude. This bug will be fixed in AC-3.0.2.
Warning #5: This release has only been lightly tested on Traditional Helicopters.
Improvements over 2.9.1b include:
WPNAV_SPEED, WPNAV_SPEED_UP, WPNAV_SPEED_DN, WPNAV_ACCEL allows configuring speeds and acceleration during missions
How to upgrade:
1. Make sure you are using Mission Planner 1.2.59 or newer (get it here)
2. Click on the MissionPlanner's Hardware, Install Firmware screen. The version numbers should appear as "ArduCopter-3.0.1", then click the appropriate frame icon and it should upgrade as per usual.
3. Reduce the Loiter and Alt Hold PIDs if you have modified them from the defaults. The modified PID values for the 3DR frame can be seen in the image below.
Note: Nav parameters have been combined with Loiter so do not be concerned if you can't find them.
5. Try out the new version in stabilize mode first, then alt-hold, then loiter and finally RTL and Auto.
Numerous How-To videos are available:
Special Thanks to Marco, DaveC and the large number of testers on the pre-release thread who put their copters at risk during the extended testing period. Some of their videos can be found here, here, here, here, here and here. Thanks also to MichaelO for the MP changes required for this release.
All feedback welcome. Please put your questions, comments (good and bad!) below.
I didn't use it since a very long time. I remember i had reliable results for terrain following at a couple meters altitude. I remember that i had single spikes from time to time in the logs but they were filtered by the code.
Because of the hard acoustic environment on a copter, it will be difficult to get good results at more than perhaps 4 - 5 meters altitude because of the degraded signal / noise ratio.
For better signal / noise ratio results a very directive sensors would be better, but it will need a small gimbal...
I did use thin foam from a MP3 player helmet. Around 0.5 mm thick. It is directly in front of the sensor, not on the horn. Adding a second foam on the horn entrance could help even more.
If you listen for a condenser microphone in the wind without windshield, you will understand what's going on in the ultrasonic sensor. The same thing happen for sure.
For sound capture in the field, we always use windshields, sometimes two layers when there is a lot of wind. And we activate a low pass filter (40 Hz to 100 Hz) directly on the microphone to clean the signal before it does enter the microphone preamplifier. We do that because the wind is inducing high level of low frequency content (even with the windshield) saturating the amplifiers if there is no protection.
Thanks i get the general idea, i was just wondering how much or how little foam and where to locate it. I was not really sure how well the waves can handle passing thru foam even if its not dense.
I saying all this, how about the optical sensor? I know its not working in 3.0.1 but I don't see very much info around on how well this works and how accurate it is compared to the sonar. For low level flying accuracy between 0-2 meters I would have thought this would be a logical choice to develop fully don't you think?
do we have anyone with some good testing data and information about how stable and accurate the optic sensor is? I would be interested to hear more on this option.
They do different things, I thought? Sonar gives height hints, optical flow gives lateral position hints.
ok, so then using both should in theory be able to give a loiter hold without GPS? Has anyone done this?
Thank-you Randy ... That was very helpful. I'll adjust my line of thinking when using the conditional commands.
So if you disable the fence through the mission planner, and start with the switch in the off position then you should be good. Basically as long as the switch position matches the set-up in the mission planner then you'll be ok.
By the way, I think we're going to remove the ability to enable/disable the fence for 3.1. The thinking is that it just adds a layer of potential problems giving people the ability to easily turn it on and off. We'd prefer if instead we can get to the position where everyone just leaves it on all the time.