From 115cf4d5720ed021a28c3457a9b63b32c29c57d5 Mon Sep 17 00:00:00 2001
From: Matthias Grob <maetugr@gmail.com>
Date: Tue, 30 Aug 2022 11:32:19 +0200
Subject: [PATCH] Helicopter: More intuitive yaw direction configuration for
 the common cases

---
 .../ActuatorEffectivenessHelicopter.cpp               |  3 +--
 src/modules/control_allocator/module.yaml             | 11 ++++++++---
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/modules/control_allocator/ActuatorEffectiveness/ActuatorEffectivenessHelicopter.cpp b/src/modules/control_allocator/ActuatorEffectiveness/ActuatorEffectivenessHelicopter.cpp
index e38fedd94f..e8c537db23 100644
--- a/src/modules/control_allocator/ActuatorEffectiveness/ActuatorEffectivenessHelicopter.cpp
+++ b/src/modules/control_allocator/ActuatorEffectiveness/ActuatorEffectivenessHelicopter.cpp
@@ -134,10 +134,9 @@ void ActuatorEffectivenessHelicopter::updateSetpoint(const matrix::Vector<float,
 	// actuator mapping
 	actuator_sp(0) = mainMotorEnaged() ? throttle : NAN;
 
-	actuator_sp(1) = control_sp(ControlAxis::YAW)
+	actuator_sp(1) = control_sp(ControlAxis::YAW) * _geometry.yaw_sign
 			 + fabsf(collective_pitch) * _geometry.yaw_collective_pitch_scale
 			 + throttle * _geometry.yaw_throttle_scale;
-	actuator_sp(1) *= _geometry.yaw_sign;
 
 	for (int i = 0; i < _geometry.num_swash_plate_servos; i++) {
 		actuator_sp(_first_swash_plate_servo_index + i) = collective_pitch
diff --git a/src/modules/control_allocator/module.yaml b/src/modules/control_allocator/module.yaml
index f3b0636f29..ac63edd396 100644
--- a/src/modules/control_allocator/module.yaml
+++ b/src/modules/control_allocator/module.yaml
@@ -449,6 +449,7 @@ parameters:
             short: Scale for yaw compensation based on collective pitch
             long: |
               This allows to add a proportional factor of the collective pitch command to the yaw command.
+              A negative value is needed when positive thrust of the tail rotor rotates the vehicle opposite to the main rotor turn direction.
 
               tail_output += CA_HELI_YAW_CP_S * collective_pitch
           type: float
@@ -462,6 +463,7 @@ parameters:
             short: Scale for yaw compensation based on throttle
             long: |
               This allows to add a proportional factor of the throttle command to the yaw command.
+              A negative value is needed when positive thrust of the tail rotor rotates the vehicle opposite to the main rotor turn direction.
 
               tail_output += CA_HELI_YAW_TH_S * throttle
           type: float
@@ -472,9 +474,12 @@ parameters:
           default: 0.0
         CA_HELI_YAW_CCW:
           description:
-            short: Change yaw direction
+            short: Main rotor turns counter-clockwise
             long: |
-              By default, positive thrust of the tail rotor is expected to rotate the vehicle clockwise. Set this parameter to true if the tail rotor provides thrust in the other direciton.
+              Default configuration is for a clockwise turning main rotor and
+              positive thrust of the tail rotor is expected to rotate the vehicle clockwise.
+              Set this parameter to true if the tail rotor provides thrust in counter-clockwise direction
+              which is mostly the case when the main rotor turns counter-clockwise.
           type: boolean
           default: 0
 
@@ -930,7 +935,7 @@ mixer:
                         name: CA_HELI_YAW_CP_S
                       - label: 'Yaw compensation scale based on throttle'
                         name: CA_HELI_YAW_TH_S
-                      - label: 'Yaw direction is CCW'
+                      - label: 'Main rotor turns counter-clockwise'
                         name: CA_HELI_YAW_CCW
                       - label: 'Throttle spoolup time'
                         name: COM_SPOOLUP_TIME