Flight Modes

Flight modes are a framework we created to allow changes to be made to the Flight behavior of the Crazyflies during a test. They have been implemented as an enum structure so that only one flight mode can be active at a time. Each Crazyflie has its own independent flight modes, so we can customize the flight patterns of each Crazyflie in the swarm separately, or as a group.

The enum is shown below (code in CCrazyflie.h):

enum FlightMode{
	LANDING_MODE = 0,
	TAKEOFF_MODE = 1,
	HOVER_MODE = 2,
	MIRROR_MODE = 3,
	HAND_MODE = 4,
	GROUNDED_MODE = 5,
	STEP_MODE = 6,
	KILL_MODE = 7
};

Current Flight Modes

(List as of 7/26/16)

Simple Flight Modes

• Landing Mode (0):
  • Changes z-setpoint to 0 and when Crazyflie is close enough to the ground automatically switch to Grounded Mode
• TakeOff Mode (1):
  • Enable PID controller for autonomous flight, hold position at default coordinates
• Grounded Mode (5):
  • Crazyflies Setpoints Forced to 0, NO CONTROLLER CALCULATION DONE (used for sitting on the ground waiting for command)
  • Note: Also resets Controller Error to prevent integrator wind-up

Formation Flight Modes

• Mirror Mode (3):
  • Swarm Forms a Triangle around Crazyflie 1
  • Crazyflie 1 Moves in a Step Pattern (diagonally back and forth)
  • Crazyflies 2, 3, and 4 follow Crazyflie 1 while maintaining the Triangle Formation
• Hand Mode (4):
  • Crazyflies wait for Hand Gesture Commands

Unused Flight Modes

• Hover Mode (2):
  • Not used yet (Could be used to reset the Crazyflie setpoints back to default)
• Step Mode (6):
  • Similar to Crazyflie1's behavior when in Mirror Mode, but for all Crazyflies (used to verify Model Parameters).
• Kill Mode (7):
  • Discontinued version of Grounded Mode (forces all setpoints to 0 but would continue calculating Controller)

Landing Mode

Landing Mode is more complex than some of the other modes in that when a certain condition is reached, it will automatically switch to a different Flight Mode. A flow chart of the process is shown here:

And the code used to implement this is shown below (code in vrpn.cpp):

void nearGround()			//During Landing Mode checks how close to ground quad is for shutdown
{
	if((cflieCopter1->m_enumFlightMode == LANDING_MODE)  && (zPosition1 < 0.05))
	{
		cflieCopter1->m_enumFlightMode = GROUNDED_MODE;
	}
if(cflieCopter2){  //Only sends command if Crazyflie 2 exists for this test (CLIENT WILL CRASH IF COMMANDING NON-EXISTENT CRAZYFLIE)
	if((cflieCopter2->m_enumFlightMode == LANDING_MODE)  && (zPosition2 < 0.05))
	{
		cflieCopter2->m_enumFlightMode = GROUNDED_MODE;
	}
}
if(cflieCopter3){  //Only sends command if Crazyflie 3 exists for this test
	if((cflieCopter3->m_enumFlightMode == LANDING_MODE)  && (zPosition3 < 0.05))
	{
		cflieCopter3->m_enumFlightMode = GROUNDED_MODE;
	}
}
if(cflieCopter4){  //Only sends command if Crazyflie 4 exists for this test
	if((cflieCopter4->m_enumFlightMode == LANDING_MODE)  && (zPosition4 < 0.05))
	{
		cflieCopter4->m_enumFlightMode = GROUNDED_MODE;
	}
}
}

This function is scanned at each iteration of the mainloop.

---

Main Directory Crazyflie Swarm Home | PC Client Software | USB Radio | Firmware | FAQ Modifications Directory Controller | Logging | Keyboard Commands | Changing Radio Channel | Flight Modes | Callbacks | Adding a Crazyflie | Firmware