First, I installed the official 3.5.7 firmware and ran it quickly.
After the mission, the automatic disarm was really easy.
However, when the helicopter takes off after spooling up
The helicopter rotates heavily.
In the process,
After reaching the rpm value set by the governor, the rpm gradually decreases
And the RPM that was reduced is restored again.
Tail rotor that was neutral was pitch (sound is very aggressive)
3-1) If the pitch angle of the tail rotor does not become neutral, the helicopter rotates when taking off.
3-2) When the pitch angle of the tail rotor becomes neutral
Helicopter take off reliably
I think this is the first time the pitch rotor enters the tail rotor while spooling up.
And the vibration of the helicopter has become too ridiculous.
I do not know if itās obvious on the surface, but the vibrations seen in the Mission planner are unusual.
Here I attach tlog, blog, and video.
01 and 02 are landing images.
I think it is neat.
03 is the take-off video of the problem.
I am poor in my English ability.
If you look at the video, I think you can fully understand what Iām talking about.
I think this is due to taking off in auto and the helicopter is aligning itself, or pointing at the first waypoint at liftoff. If you point the helicopter at the first waypoint before takeoff, or take off manually and fly the helicopter so it is pointing at the first waypoint, it will be less scary. This is why when using automatic takeoff with a helicopter you must be a safe distance from it, as they can go the wrong direction, including straight at you, when spline waypoints are used.
Again the vibration is a characteristic of the engine used in that helicopter.They are not smooth running like a two-stroke.
But before the takeoff there are no waypoints.
There was no manual flight.
The mission is take off from the seat of the aircraft, and is an RTL mission after an altitude of 30 meters.
It is very embarrassing for the first time that a pitch enters the tail wing during helicopter spooling up.
And I tried setting the parameter H_LAND_COL_MIN once
There is no noticeable change in the movement of the helicopter.
If this parameter is set, can you tell me what the helicopter is doing?
Yeah. You engaged Auto on the ground. So when the helicopter takes off if it is not perfectly pointed at the first waypoint, it is going to quickly yaw to face it. Which is exactly what it did. This is actually quite dangerous when using spline waypoints because they many times donāt fly directly to the first waypoint, but instead fly a spline path. Depending on how the first and second waypoints are situated, this can cause the helicopter to fly in an unexpected loop and hit something, or even fly into you if you are too close to it.
I highly dislike automatic takeoffs with helicopters, regardless of whether or not people claim they do it all the time. I prefer to run post takeoff checks on the attitude and nav controllers before Iāll hand it over to the autopilot.
Chris
Thank you for quick response.
There is one question.
When I do automatic missions
Takeoff -> Waypoint -> etc ā¦-> RTL
The helicopter turning his head like that would take his head off after it had taken off and reached the altitude i
set.
I do not understand why heli turn his head from the ground.
In addition, the video I showed is only Take off -> RTL
It does not contain any waypoints.
I understand that the absence of waypoints or spline waypoints means that helicopters will never turn their heads.
I have tried a lot of automatic takeoff and landing of helicopter until now, but this is the first time.
Well, the log I looked at there was a waypoint. It flew to it and then RTL and landed and shut down properly.
Yes, the system is designed to be fully autonomous from takeoff to landing. But I fly the big ones you ride in, and despite the fact that a Honeywell or Genesys autopilot is way more advanced in a full-size than what ArduPilot is, it is unthinkable to engage an autopilot with the helicopter in a critical flight profile like takeoff or landing. So I donāt do it. I come from training where safety and emergency procedures are taught, practiced, lived and breathed if you want to stay alive to fly another day. That is not taught in the drone world, as a result people wad 'em up every day. I prefer to fly my $10,000 helicopters, not retrieve them from the crash site.
I totally agree with Chris.
In the past I have done auto takeoffs and had several tricky situations. For 3 years now I always takeoff in Stabilize and switch to Auto after the Heli reached about 10-15 meters altitude.
Uh ā¦
Iām totally wrong.
I wanted to make the least of the people involved in the flight, but I did not know that the auto takeoff was so dangerous.
Uh ā¦
Iām totally wrong.
I wanted to make the least of the people involved in the flight, but I did not know that the auto takeoff was so dangerous.
Itās not as good as I thought.
It is user preference and what youāre comfortable with. You are depending on GPS close to the ground, and GPS is notoriously inaccurate close to the ground. You have no control over the machine if something goes wrong. When using spline waypoints, unless you have experience setting them, the helicopter can go in an unexpected direction. You have no indications as to whether or not the attitude and nav controllers are working properly.
It is a use at your own risk type of thing. Make sure you stay well back from it. Keep bystanders away from it. It is not a like a multi-rotor drone - if it tips over and you get a rotor strike it can send pieces flying with lethal force. Any RC helicopter 700 class and bigger can dismember and kill people. They are not toys. Realize the limitations of the system and if you do use it follow safety procedures so nobody gets hurt. You witnessed how fast they can spin on an auto takeoff. If it goes into dynamic rollover, gets a rotor strike and blows the EKF, it can come at you like a missile and you canāt get out of the way fast enough. I got a video of a 700 where that happened and that machine took a tree down. If itās a 450 or 500 Iām not concerned. But you arenāt flying one of those.
What I recommend if youāre new to these things is to set up some missions in a wide open area using spline waypoints. Set your waypoints at a safe altitude. Take off manually in Stabilize or Acro, fly the helicopter a bit to make sure it handles ok. Then switch to Loiter or Pos Hold and let it hover and observe that it holds position ok. If everything looks good, now engage Auto in the air. And watch what it does.
This will give you a āfeelā for how spline waypoints work, and the path the helicopter can sometimes take to get to the first waypoint. It tends to accelerate and decelerate at the programmed limits for WPNAV. And while flying spline waypoints is really smooth, the movements it makes to start and end a flight are not smooth at all. Bill and I have some code that weāre testing to make this smoother for Auto flight, but I havenāt gotten back to testing it yet.
For starting out with a big helicopter, using the manual takeoff and landing will get you more familiar with how it works when it executes an auto mission, without the dangers close to the ground. Then after you get more familiar with it, and how it acts, you can decide whether or not you want to trust it close to the ground.
Thereās some settings youāll want to make to get the helicopter to fly nice. In 3.6 there is new ATC (Attitude Controller) settings for angular rate in deg/sec. You can set those to slow a big heli down on pitch, roll and yaw response (both manual and autopilot) so itās not quite so scary as a UAV.
And the WPNAV parameters. You will see ones for horizontal acceleration and climb and descent rates. These are going to affect how the helicopter behaves if you use an auto takeoff, as well as in flight.
If, during testing and tuning for waypoint flying, you use RTL or auto land always be ready to switch to manual flight mode in case it doesnāt shut down by itself. If it doesnāt shut down within a couple seconds, donāt stand there and watch it to see whatās it going to do next. This system is not going to be reliable with a vibration-prone helicopter. Your vibration levels are barely acceptable in flight. On the ground with it running they are not acceptable. So automatic landing is going to be hit and miss, as it will probably have an issue detecting the ābumpā when it contacts the ground. If you have the H_LAND_COL_MIN set right it should work. But with vibe spikes hitting over 100 I wouldnāt trust it. That is where an accident could happen. So with your particular helicopter landing manually will probably be the safest. You can set your RTL so it doesnāt try to land it by itself. The landing detector works pretty good if you have everything tuned, vibrations are damped good, and itās landing on a level surface. But itās very difficult to damp the vibration from the F-50 four-stroke engine - that engine is a thumper.
Wowā¦!!
Is this a newly added parameter?
I have installed the 3.6.0 firmware, but I have not verified all the parameters yet.
Sorry, can I get a list of the newly added parameters?
In the case of vibration, I can not confirm whether it is the vibration of the helicopter itself or the vibration due to the hunting due to the PID setting.
In 3.6 the new angular rate settings are these
ATC_RATE_MAX
ATC_RATE_R_MAX
ATC_RATE_Y_MAX
You can set these in deg/sec of maximum rotation rate of your airframe at full control deflection. So, for instance, if you want the helicopter to piro at one revolution every 2 seconds at full rudder input, you can set ATC_RATE_Y_MAX to 180.
Since most re-purposed 3D helicopters can do 1000+ deg/sec I have found these new params quite useful to tame them down for more scale quality flight characteristics. That tail yaw snap in your one video was probably around 700-800 degrees/sec yaw rate. Setting that to 180 will make it a lot smoother.
Hi, Chris.
I heard your advice well.
Ricoman is a colleague who works with me.
What he asked was like what I was wondering.
Thank you very much for everybodyās help.
Iāll keep trying test.
And Iāll feedback for you.