VTOL altitude hold system with automatic ground effect compensation
First Claim
1. In an automatic altitude hold control system for an aircraft subject to ground effect, said control system including a manual controller for controlling the lift of the aircraft, a parallel servoactuator including a trim actuator and a controller force feel spring for coupling to said manual controller, an out-of-detent and in-detent spring deflection condition sensor for providing a signal indicative of a displacement of said manual controller, a controller position sensor for providing a signal corresponding to a position of said manual controller, and a servo amplifier responsive to altitude error for normally positioning said manual controller for reducing said altitude error to zero, apparatus responsive to a transition of said aircraft from an altitude outside an aircraft ground effect zone to an altitude within the aircraft ground effect zone and vice versa for automatically compensating said system for the resulting change in lift of the aircraft by driving said trim actuator in a direction which relieves any force being exerted by a human pilot in order to maintain the new commanded altitude, said apparatus comprising(a) a collective position synchronizer responsive to said controller position sensor, for supplying a signal corresponding to the controller position at a previously held altitude,(b) means for sensing the presence and absence of ground effect on said aircraft, and(c) means responsive to said ground effect sensor means for supplying said synchronizer signal corresponding to the controller position to said servo amplifier for driving said trim actuator to compensate said system.
3 Assignments
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Accused Products
Abstract
During a transition of a VTOL aircraft such as a helicopter, from one altitude held without its ground effect zone to another to be held within its ground effect zone, or vice versa, a collective stick position synchronizer which can memorize the proper trim condition at the previous altitude in conjunction with the stick force sensor out-of-detent logic and a low vertical speed sensor, together constituting a ground effect zone detector, is used to drive the collective stick trim actuator in a direction which relieves any force being exerted by the pilot in order to maintain the new commanded altitude.
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Citations
10 Claims
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1. In an automatic altitude hold control system for an aircraft subject to ground effect, said control system including a manual controller for controlling the lift of the aircraft, a parallel servoactuator including a trim actuator and a controller force feel spring for coupling to said manual controller, an out-of-detent and in-detent spring deflection condition sensor for providing a signal indicative of a displacement of said manual controller, a controller position sensor for providing a signal corresponding to a position of said manual controller, and a servo amplifier responsive to altitude error for normally positioning said manual controller for reducing said altitude error to zero, apparatus responsive to a transition of said aircraft from an altitude outside an aircraft ground effect zone to an altitude within the aircraft ground effect zone and vice versa for automatically compensating said system for the resulting change in lift of the aircraft by driving said trim actuator in a direction which relieves any force being exerted by a human pilot in order to maintain the new commanded altitude, said apparatus comprising
(a) a collective position synchronizer responsive to said controller position sensor, for supplying a signal corresponding to the controller position at a previously held altitude, (b) means for sensing the presence and absence of ground effect on said aircraft, and (c) means responsive to said ground effect sensor means for supplying said synchronizer signal corresponding to the controller position to said servo amplifier for driving said trim actuator to compensate said system.
Specification