From 782f06b93c5cbf496b1d74eefd8d4cde296453c0 Mon Sep 17 00:00:00 2001 From: menschel Date: Mon, 13 Jan 2025 08:49:02 +0100 Subject: [PATCH] Docs: Plane: Add hint to solve 1Hz pitch oscillations caused by autotune. --- plane/source/docs/automatic-tuning-with-autotune.rst | 11 +++++++++++ ...y-control-system-for-speed-height-tuning-guide.rst | 3 +++ 2 files changed, 14 insertions(+) diff --git a/plane/source/docs/automatic-tuning-with-autotune.rst b/plane/source/docs/automatic-tuning-with-autotune.rst index 6aab6c7c97..7569f71e5a 100644 --- a/plane/source/docs/automatic-tuning-with-autotune.rst +++ b/plane/source/docs/automatic-tuning-with-autotune.rst @@ -153,6 +153,17 @@ This is a special level that does not change the rates or time constant (ie like Completing the tune =================== +.. _automatic-tuning-with-autotune-completing-the-tune: + +.. warning:: + + If you have successfully tuned your plane with Autotune and see oscillations on the pitch axis around 1 Hz, + check if :ref:`PTCH_RATE_I` far exceeds :ref:`PTCH_RATE_P`. + This is an unwanted result of Autotune for Plane and it typically becomes visible if you fly straight for + a longer distance. Autotune does blindly copy the value of :ref:`PTCH_RATE_FF` to + :ref:`PTCH_RATE_I` due to a wrong design decision. In this case reduce the value of + :ref:`PTCH_RATE_I` to half of it's value. + Once you have learned reasonable tuning parameters with autotune you should complete the tune by manually tuning some other key parameters. diff --git a/plane/source/docs/tecs-total-energy-control-system-for-speed-height-tuning-guide.rst b/plane/source/docs/tecs-total-energy-control-system-for-speed-height-tuning-guide.rst index f2faae6079..83ce98a56f 100644 --- a/plane/source/docs/tecs-total-energy-control-system-for-speed-height-tuning-guide.rst +++ b/plane/source/docs/tecs-total-energy-control-system-for-speed-height-tuning-guide.rst @@ -183,6 +183,9 @@ increasing the value of :ref:`TECS_TIME_CONST` in increments of where throttle changes cause noticeable pitch angle changes. Ideally you should improve your pitch loop tuning first, before adjusting :ref:`TECS_PTCH_DAMP` and :ref:`TECS_TIME_CONST` as described here. + Low frequency pitch oscillations around 1Hz are an indicator that :ref:`PTCH_RATE_I` is + too high. Refer to the warning :ref:`Completing the tune `. + If using airspeed sensing, adjust the value of :ref:`TRIM_THROTTLE` so that it matches the average amount of throttle required by the