Implement RC fail-safe

gazebo/flix.h

@@ -25,6 +25,7 @@ float loopFreq;
 float motors[4];
 int16_t channels[16]; // raw rc channels
 float controls[RC_CHANNELS];
+float controlsTime;
 Vector acc;
 Vector gyro;
 Vector rates;
@@ -48,6 +49,8 @@ void sendMavlink();
 void sendMessage(const void *msg);
 void receiveMavlink();
 void handleMavlink(const void *_msg);
+void failsafe();
+void descend();
 inline Quaternion FLU2FRD(const Quaternion &q);
 
 // mocks

gazebo/simulator.cpp

@@ -25,6 +25,7 @@
 #include "log.ino"
 #include "cli.ino"
 #include "mavlink.ino"
+#include "failsafe.ino"
 #include "lpf.h"
 
 using ignition::math::Vector3d;