lördag 4 januari 2020

Automated Flight Based on Predictive Flight Simulation


WSJ reports:
  • MAX Crashes Strengthen Resolve of Boeing to Automate Flight. 
  • Boeing, Airbus and industry experts for long have planned more technology to prevent pilot error.
  • Boeing Co. is increasingly committed to transferring more control of aircraft from pilots to computers after two crashes exposed flaws in an automated system on its 737 MAX that overpowered aviators in the disasters. 
  • Executives at Boeing and other makers of planes and cockpit-automation systems for some time have believed more-sophisticated systems are necessary to serve as backstops for pilots, help them assimilate information and, in some cases, provide immediate responses to imminent hazards...
Jetliners have auto-pilot systems relieving pilots from routine flight control when cruising, while a fighter jet like the JAS Gripen requires automatic control to handle the built-in instability allowing quick turns. 

An auto-pilot is like a cruise-control on a car set to maintain a given speed as an option for steady cruising, without true capability to replace the pilot under variable conditions. Not so sophisticated. 

The forward canard of JAS Gripen is used to automatically stabilise the flight, which is too delicate for manual pilot control. The interaction between the pilot and the control system carries the danger of PIO pilot induced oscillations, which caused two early JAS crashes before the software was tamed to slower turns. 

The two Boeing 737 Max crashes were caused by the MCAS control system installed to help the pilot  stay away from stall in climb at full throttle after start by automatically pointing the nose down upon input from a single angle of attack sensor. But the sensor failed and MCAS forced the plane into the ground. Not so sophisticated.

So, Boeing is now searching for "more-sophisticated systems to respond to imminent hazards" in different forms of automated flight.     

Development of automated flight would be greatly helped if predictive computational simulation of the dynamic action of an airplane from controls including throttle, rudder, elevators, slats, flaps and spoilers, was possible, since it could replace difficult time-consuming real flight testing. 

Standard software for CFD Computational Fluid Dynamics is not truly predictive, since it hinges on wall and turbulence models, which are prescriptive rather than predictive, and thus do not well serve this purpose. 

But there is light in the tunnel (for Boeing): DFS Direct Finite Element Simulation is new unique CFD software offered by Icarus Digital Math allowing prediction of the full dynamic flight characteristics of an airplane from first principle physics, without wall and turbulence models. 

DFS thus opens the possibility to construct a flight simulator based on first principle physics, which is truly predictive and as such can contribute to the development of (safe) automated flight.   

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