Thrust and flight path control decoupling system

In combination in an autothrottle control system for an aircraft having a first input coupled to first means for providing a signal representative of longitudinal acceleration information of said aircraft, and a second input coupled to second means for providing a signal representative of air speed error of said aircraft:

• signal processing means responsive to a plurality of signals including signals representative of longitudinal acceleration and change in thrust information for providing first and second compensation signals;
• third means for combining said first compensation signal with said signal representative of longitudinal acceleration information of said aircraft;
• and,
• fourth means for combining said second compensation signal with said signal representative of air speed error of said aircraft.

A system for computing speed perturbations due to path deviations of an aircraft to provide first and second compensating signals for coupling respectively to autothrottle control system input signal control channels representative of longitudinal acceleration and air speed error comprising:

• first means for generating a signal representative of acceleration of said aircraft due to change in flight path angle;
• a washout circuit responsive to said signal representative of acceleration of said aircraft due to change in flight path angle for providing said first compensating signal;
• low pass filter circuit means responsive to said first compensating signal for providing said second compensating signal;
• and,
• wherein said first means comprises means for generating a signal representative of
• -V + .sub.W.sup.g .DELTA. T
• where V is longitudinal acceleration, g is gravity acceleration constant, W is weight, and .DELTA. T is change in thrust.

In combination in a control system for an autothrottle utilizing a thrust control damping signal and a signal representative of air speed error coupled to said autothrottle to provide input signal information for said autothrottle:

• first means responsive to acceleration of the aircraft due to change in flight path angle and including high pass filter circuit means for providing a first compensation signal;
• second means for combining said first compensation signal with said thrust control damping signal;
• third means including low pass filter circuit means responsive to said first compensation signal for providing a second compensation signal;
• and
• fourth means for combining said second compensation signal with said signal representative of air speed error.

A system for providing a first compensated thrust control damping signal and second compensated thrust control reference signal for coupling as input signals to an autothrottle to inhibit short term thrust control of an aircraft due to small flight path angle perturbations comprising:

• first means including washout circuit means for generating a first compensation signal;
• second means including pseudo integrator circuit means for generating a second compensation signal;
• third means for combining said first compensation signals with said thrust control damping signal and said second compensation signal with said thrust control reference signal;
• and
• fourth means including time constant programming control signal generating means for providing decreasing washout and pseudo integrator circuit time constants with increasing air speed errors.

In an autothrottle control system having first and second input signals representative respectively of compensated longitudinal acceleration and compensated air speed error coupled as input signals to the autothrottle;

• compensating means comprising:
• first means for providing a third signal representative of engine pressure ratio or fan speed;
• second means for providing a fourth signal representative of pitch attitude compensated longitudinal acceleration;
• third means for providing a fifth signal representative of air speed error;
• fourth means comprising summing amplifier means responsive to said third and fourth signals for providing a sixth signal;
• fifth means comprising washout circuit means responsive to said sixth signal for providing a first compensation signal;
• sixth means comprising summing amplifier means for combining said first compensation signal with said fourth signal to provide said first input signal representative of compensated longitudinal acceleration for use as a new thrust control damping signal;
• seventh means including pseudo integrator circuit means responsive to said first compensation signal for providing a second compensation signal;
• and
• eighth circuit means means comprising summing amplifier circuit means for combining said second compensation signal with said fifth signal to provide said second input signal representative of compensated air speed error for use as a new thrust control reference signal.

In combination in a control system for an autothrottle utilizing a thrust control damping signal and a signal representative of airspeed error coupled to said autothrottle to provide input signal information for said autothrottle;

• first means responsive to acceleration of the aircraft due to change in flight path angle and including high pass filter circuit means for providing a first compensation signal;
• second means for combining said first compensation signal with said thrust control damping signal;
• third means including low pass filter circuit means responsive to said first compensation signal for providing a second compensation signal;
• fourth means for combining said second compensation signal with said signal representative of airspeed error;
• and
• time constant programming circuit means coupled to said high and low pass filter circuit means for varying the respective time constants of said high and low pass filter circuit means.

In combination with an aircraft longitudinal axis control system having an automatic throttle control system including a means for providing a thrust control damping signal;

• and
• means for providing an airspeed representative reference signal, a system for inhibiting short term throttle activity due to control coupling with the flight path control loop comprising:
• means for providing a first compensation signal representative of the longitudinal acceleration of said aircraft, resulting from coupling with the flight path control loop;
• washout circuit means for filtering said first compensation signal to eliminate long term components;
• means for combining said first filtered compensation signal with said thrust control damping signal to provide a compensated thrust control damping signal;
• low pass filter means responsive to said first filtered compensation signal providing a second compensation signal;
• and
• means for combining said airspeed representative reference signal with said second compensation signal to provide a compensated thrust control reference signal.