Safety in prototype flight Sikkerhedskonference Trafikstyrelsen Associate Professor M.Sc. Math, PhD Anders la Cour-Harbo Sikkerhedskonference, October 31, 2013 1
Sikkerhedskonference, October 31, 2013 2 UAS Group
Sikkerhedskonference, October 31, 2013 3 UAS Group Organization Aalborg University Faculty of Engineering and Science Department of Electronics Systems Section of Automation and Control
History 2010 2009 2013 2008 2011 2005 2010 2011 2006 Sikkerhedskonference, October 4
Prototype flight No or little flight hours No safety record and often little experience with platform More difficult for crew to operate/intervene Sikkerhedskonference, October 31, 2013 5
Sikkerhedskonference, October 31, 2013 6 UAS Group Platform changes
Prototype flight No or little flight hours No safety record and often little experience with platform More difficult for crew to operate/intervene Accept a relatively high probability of damage or loss of aircraft Extended safety measures often necessary Distance, instruct spectators, fly according to plan Considerations on emergency actions Safety zone, first responders, aircraft recovery Sikkerhedskonference, October 31, 2013 7
Sikkerhedskonference, October 31, 2013 8 UAS Group Avoid single points of failure (whenever possible)
Sikkerhedskonference, October 31, 2013 9 UAS Group Test in simulation to the extend possible
Guiding principles (initially, back in 2003) Use off-the-shelf RC equipment (as much as possible). No people close to flight path. Rule of thumb: 45 degree separation Safety briefing for spectators / new team members. Designated landing zone. Area marked by small fence, grass border or other visible markings. Must be kept clear by all except pilot and possibly other persons necessary for the flight. Camera always running when engine is running. High reliablity that pilot can take control at all times. Take no chances, do not rely on luck! Sikkerhedskonference, October 31, 2013 10
Cessna 182 Skylane loss of control Cessna 182 model 11 kg, 260 cm span Sudden loss of remote control Regained control and safe landing (no engine, deliberately) http://www.youtube.com/watch?v=e7aak74j4cg Sikkerhedskonference, October 31, 2013 11
Cessna 182 Skylane loss of aircraft No actuator response immediately after take-off Control regained after a few second, and remote control was in full right Airplane flipped and crashed. Subsequent test of OBC revealed that 35 MHz receiver was jammed by OBC power supply (PC/104 system). 2.4 GHz system (new at the time) worked without problem in same setup. Lesson learned: Range test! Sikkerhedskonference, October 31, 2013 12
Sikkerhedskonference, October 31, 2013 13 UAS Group Bergen crash Normal speed Slow motion http://www.youtube.com/watch?v=u42mmegcedu http://www.youtube.com/watch?v=til5jo7owcs
Bergen crash During step tests the helicopter suddenly became unstable and the pilot conducted a safety landing. A maneuver was too extreme and the main rotor struck the GPS antenna. As the helicopter landed hard the rotor blade struck the tailboom and magnetometer, which was propelled 30 meters away. Lesson learned: Stay in flight envelope! Careful mounting of sensors! Sikkerhedskonference, October 31, 2013 14
Bergen faulty servo During flight erratic movements on collective Ended in sudden climb. Pilot cut engine to avoid accident, and helicopter dropped several meters. 2.35 2.50 http://www.youtube.com/watch?v=mq_wc9xwpn0 Sikkerhedskonference, October 31, 2013 15
Bergen faulty servo We set up a test stand to monitor the servo movements. This revealed the problem. Lesson learned: Do not take chances! Listen to experience! http://www.youtube.com/watch?v=rc5xsg5u2fw Sikkerhedskonference, October 31, 2013 16
Additional guiding principles (as of 2013) ALWAYS keep camera running when the engine is running. ALWAYS abort when unexpected things happen. Check list prior to each flight. Pilot must be part of the development team. Informing all participants of flight intensions. Continuous radio communication (using professional system from 3M). Range check after every change in mechanics and/or electronics. Dry runs with software changes. Telemetry availability is important during flight. Use solid state disc and make sure to record certain vital signals. Be clear on aircraft capabilities and stay with the agreed flight envelope. Sikkerhedskonference, October 31, 2013 17
Sikkerhedskonference, October 31, 2013 18 UAS Group Wind turbine meteorology
MANY things can go wrong Navigation Determine position, velocities, system states. Control Stabilization and trajectory tracking Environment perception and guidance Detecting obstacles, sensing environment, computing trajectories Fault tolerance and adaptability System robustness, fault resilience, safety measures Group actions and cooperation Several entities working together, synergetic effects, swarms Cognitivity Intelligence, decisions, learning, and adaption Sikkerhedskonference, October 31, 2013 19
Sikkerhedskonference, October 31, 2013 20 UAS Group When backup system is working http://www.youtube.com/watch?v=-egmxyzfiqs