ArduPilot: Prevent std::future_error in takeoff, and return attitude in euler angles

[lamlaaaam]

This PR addresses 2 issues when using MAVSDK with ArduPilot. These were tested on ArduPilot SITL Copter-4.4.4, using MAVSDK v2.0.1.

Takeoff crashes if the switch to Guided mode fails

Observation

When ArduPilot SITL starts up, it takes time before the GPS initializes and for the UAV to obtain a position estimate. During this time, if the takeoff command is given, an unhandled std::future_error exception is thrown.

Cause

Within Action_Impl::takeoff_async_apm, if set_flight_mode_async fails, it triggers the callback to set a failed result. However, it still calls send_takeoff_command, which triggers the same callback, and tries to set another result value for a fulfilled promise.

Fix

Just don't call the send_takeoff_command if switch to Guided mode fails.

NaN values received for attitude in euler angles

Observation

The values received for roll, pitch, yaw in the telemetry are NaN.

Cause

In TelemetryImpl::process_attitude, the values are extracted from the received telemetry message and correctly populated into a Telemetry::EulerAngle struct. However, this struct is then never used again. Instead, it grabs the quaternion version, and does a conversion to euler angles. I'm not sure what the actual reason causing the NaN is, but it's probably somewhere in the conversion.

Fix

Use the Telemetry::EulerAngle struct that was populated.

[JonasVautherin]

Nice ones!

[JonasVautherin]

OpenSSL is timing out for now, let's try the CI again in a few hours 👍.

[JonasVautherin]

There is a styling issue to fix, though:

diff --git a/src/mavsdk/plugins/action/action_impl.cpp b/src/mavsdk/plugins/action/action_impl.cpp
index fae1052..e75dc7e 100644
--- a/src/mavsdk/plugins/action/action_impl.cpp
+++ b/src/mavsdk/plugins/action/action_impl.cpp
@@ -407,8 +407,7 @@ void ActionImpl::takeoff_async_apm(const Action::ResultCallback& callback) const
                     if (callback) {
                         callback(action_result);
                     }
-                }
-                else {
+                } else {
                     send_takeoff_command();
                 }
             });
Error: Process completed with exit code 1.

[julianoes]

Thanks for the fixes, much appreciated!