Boots – shoes – and leggings
Patent
1982-09-30
1985-08-20
Wise, Edward J.
Boots, shoes, and leggings
364440, 244181, 244182, B64C 1300
Patent
active
045368430
DESCRIPTION:
BRIEF SUMMARY
This invention pertains to the aircraft automatic flight control art and, more particularly, to an integrated longitudinal flight control system based on total aircraft energy.
Numerous autopilot, autothrottle and flight guidance systems for use in aircraft flight control have been developed in the prior art. Such systems have often evolved in a piecemeal fashion and, particularly with respect to longitudinal axis flight control, such automatic control systems are characterized by a proliferation of control laws and hardware components. As a result, these systems are overly complex and lacking in functional integration. This has caused numerous operational and performance deficiencies, such as:
low reliability and availability,
high procurement and maintenance costs,
excessive number of sensors,
undesirable flight path and speed control coupling,
command capture overshoots and poor tracking,
excessive controller activity and turbulence resulting in poor ride quality, engine wear and waste of fuel,
loss of speed control when thrust limits,
mode switching transients,
inadequate stall/overspeed protection, and
unsatisfactory performance in windshear.
There is a long felt need in the flight control art, therefore, for a fully integrated vertical flight path and speed control system which, by developing fundamental solutions to the problem of fully coordinated elevator and throttle control, is capable of a performance level which overcomes these limitations of flight control systems known in the prior art.
SUMMARY OF THE INVENTION
It is an object of this invention, therefore, to provide an improved automatic longitudinal flight control system in which the aforementioned performance and operational deficiencies are avoided.
Another objective of this invention is to provide a universal multi-input/output longitudinal control system, with appropriately coordinated elevator and throttle commands to provide consistent, accurate, decoupled control over the aircraft's vertical flight path and speed, in any desired combination of modes and flight condition.
It is a further objective of this invention to provide the above-mentioned automatic longitudinal flight control system characteristics, using basic principles of physics and control theory, in particular, the use of thrust to control the total energy state of the aircraft and the use of elevator position to control the energy distribution.
Yet another major objective of this invention is to provide a dramatic simplification in the overall automatic control system in terms of required hardware and software, by systematic integration of all control requirements, elimination of unnecessary duplication of functions and establishment of priority use of controllers. As a result, the presently disclosed system not only realizes major improvements in automatic control system performance and operational capabilities, but also improvements in safety by preventing aircraft stall, overspeed and engine overboost, and cost of ownership by simplifying system development, certification and maintenance.
Briefly, according to the invention, the aircraft vertical flight path and speed targets are normalized into vertical flight path angle and longitudinal acceleration command signals .gamma..sub.c and V.sub.c respectively. These commands are combined with their corresponding feedback variables .gamma. and V to form the error signals nd .gamma..sub..epsilon. which, in turn, are used to produce signals representative of the specific total energy rate error E.sub.s.sbsb..epsilon. and (2), g is a constant representing acceleration due to gravity.
The specific total energy rate error E.sub.s.sbsb..epsilon. is controlled to zero by commanding incremental thrust as a function of the E.sub.s.sbsb..epsilon. signal, while the energy distribution rate error D.sub..epsilon. is controlled to zero by commanding an incremental elevator position as a function of the D.sub..epsilon. signal, thereby driving the aircraft to the desired vertical flight path and speed targets .
BRIEF DESCRIPTION OF
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Black Thomas G.
Donahue Bernard A.
Hamley James P.
The Boeing Company
Wise Edward J.
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