Things feel sluggish after autotune– how can I make it snappier?

Make sure you’ve turned up your rates on the stabilization pane! Try 450 deg/sec with a center stick rate of 180 deg/sec to start… and if you like that, turn the maximum rates up higher.

I’m getting bad AutoTune results. What should I try next?

Sadly, while AutoTune works well for most people it doesn’t work well for all vehicles. This has been significantly improved in the latest release!

That being said, there are some tips that often help:

  • Don’t stack AutoTunes. AutoTunes should be made from default tuning (there is a button on the stabilization pane to reset PIDs to default; be sure to do this for both the inner and outer loop), or…
  • Sometimes it is necessary to even turn down the default tuning. If your multirotor is prone to oscillation in leveling mode with default PIDs, turn down the inner loop coefficients on the stabilization pane. The default values are 20/15; perhaps try 12/15 for a starting point.
  • Sometimes reducing motor input/output curve fit on the bottom of the stabilization pane to 0.80 from the default 0.9 allows AutoTune to get a good system measurement.
  • If you have a lot of vibration, this can be the culprit.
    • To try software filtering: In the UAVO browser (on the “advanced” pane), select Settings → SensorSettings. Set LowpassCutoff to 40; this changes the default filter cutoff from 55 Hz to 40Hz. Set LowpassOrder to 2 (which uses a higher-order filter for the gyro data). Click the disk icon with the up arrow at the top of the UAVO browser to save this to the flight controller.
    • Ensure screws are tightened on the flight controller and consider adding mechanical filtering (e.g. o rings).

How do I setup Air Mode? What’s “HangTime”?

On the stabilization pane, “Advanced”, enable HangTime.

HangTime achieves similar (some would say better) results than Air Mode in that it allows you to engage in maneuvers while at zero throttle. For safety, it also has limits on its operation.

First, HangTime makes sure to never add more than a configured percentage of throttle to avoid excessive floating and fly-aways. The “Maximum Power Add” should be set to well under your hover power percentage.

Second, it isn’t controlled with a switch like Air Mode. Instead, it is enabled for a limited, configured time after throttle is lowered to zero.

It’s strongly recommended to use HangTime that you sure switch arming. This is for two reasons:

  • If you’re doing slow, floating maneuvers, you could hit the disarm sequence in flight. Throttle is already zero, so it would be easy to yaw or roll in a way that causes a disarm. This is not fun.
  • You don’t want the aircraft to respond to a stick disarming command while landing.

Should I use MultiShot? If so, how do I set it up?

We do not recommend MultiShot or OneShot42. OneShot125 already updates much faster than the actual response time of multirotors and propeller dynamics, and the shorter signal is more vulnerable to noise.

However, by popular demand, the setup wizard supports selecting OneShot42. Additionally, it is possible to configure output timings on the output pane to OneShot42 (42 to 83us) or MultiShot timings.

What about DShot?

DShot offers identical flight performance to OneShot125, but eliminates the need for ESC calibration.

Should I use PWM, PPM or S.Bus for receiver connection?

Serial RX (e.g. S.Bus or iBus) is best. PPM introduces more latency and consumes a timer resource on the microcontroller.

PWM uses lots of resources, is only supported by some flight controllers, and uses lots of wiring. Therefore it is not recommended.

Why is “Motors spin while armed” preferred?

We think it’s essential that it’s obvious when an aircraft is armed, so that passers-by don’t attempt to handle it and it’s clear it needs to be disarmed before it is approached. Spin while armed is the best way to attain this– it makes it obvious that if the throttle is bumped, those propellers will spin fast and the vehicle will fly.

Otherwise, it becomes possible to land and fail to disarm, and you’re just a small mistake away from severe injury.

How can I get additional help?

First, please read before contacting support. Keep in mind that dRonin is a non-profit project and all support is provided by volunteers, so please be patient.

  • dRonin Forum
  • dRonin IRC (live chat): #dRonin on; can be accessed in a web browser here