Flight control system especially suited for vtol vehicles

Abstract

Flight control systems have plural control subsystems with redundancies organized so as to provide continued but degraded control power over critical aircraft flight operating parameters even if any one complete control subsystem catastrophically fails. One example described in detail for a VTOL craft includes four groups of controls, each group comprising inputs relating to six degrees of freedom of the vehicle, at least one control computer and a plurality of actuators; each group utilizing 25% of required flight control power for the vehicle.

1 . A flight control system for a VTOL vehicle comprising at least a pair of ducted lift fans, each of said pair of ducted lift fans having a plurality of adjustable directional vanes associated therewith, said flight control system comprising:
 a plurality of groups of controls collectively supplying 100% of required control power for the flight control system; and   means enabling at least 50% of the required control power to be available upon failure of any one of said plurality of groups of controls.   
     
     
         2 . The flight control system of  claim 1  wherein said means enables at least 75% of the required control power to be available upon failure of any one of said plurality of groups of controls for use in compensation of the failed group, if necessary, and continued flight control power. 
     
     
         3 . A flight control system for a VTOL vehicle comprising at least a pair of ducted lift fans, each of said pair of ducted lift fans having a plurality of adjustable directional vanes, at least some of which are located adjacent respective inlet ends thereof; said flight control system comprising:
 n groups of controls,   each group being independent of all remaining groups and controlling adjustment of 1/n of said plurality of adjustable directional vanes.   
     
     
         4 . The flight control system of  claim 3  wherein n=4 and wherein said plurality of directional vanes comprises more than 100 vanes. 
     
     
         5 . The flight control system of  claim 4  wherein said plurality of directional vanes is divided into eight segments of substantially equal numbers of vanes, each group controlling adjustment of two of said eight segments. 
     
     
         6 . The flight control system of  claim 5  wherein said plurality of directional vanes is divided into 16 segments, each group controlling adjustment of four of said sixteen segments. 
     
     
         7 . The flight control system of  claim 3  wherein each ducted fan includes a variable pitch propeller, wherein no more than 50% of the adjustment of said variable pitch propeller is controlled by each of two of said groups of controls. 
     
     
         8 . The flight control system of  claim 3  wherein a sum of the control power of all of said groups, when in normal non-failed operational modes, is greater than the control power required to maintain control of said vehicle. 
     
     
         9 . A flight control system for a VTOL vehicle comprising at least a pair of ducted lift fans, each of said pair of ducted lift fans having a plurality of adjustable directional vanes at least some of which are located adjacent respective inlet ends thereof; said flight control system comprising:
 n groups of controls,   each group contributing approximately 1/n of total control power required for the flight control system,   each group comprising at least one control computer subsystem for controlling a plurality of actuators for a predetermined fraction of said plurality of adjustable directional vanes, such that failure of any one group leaves at least n-1/n of the control power available for controlling the directional vanes of the remaining groups.   
     
     
         10 . The flight control system of  claim 9  wherein each group comprises a plurality of sensors monitoring operational parameters of the vehicle inputting data to said at least one control computer subsystem. 
     
     
         11 . The flight control system of  claim 9  wherein n=4. 
     
     
         12 . The flight control system of  claim 11  wherein said ducted lift fans have adjustable-pitch propellers respectively controlled by 2 of said 4 groups. 
     
     
         13 . The flight control system of  claim 9  wherein each group comprises a plurality of control computer subsystems, none of which share information with any other of said control computer subsystems. 
     
     
         14 . The flight control system of  claim 9  wherein:
 said ducted lift fans have adjustable-pitch propellers, and said flight control system controls movement of said vehicle in six degrees of freedom, each group contributing to control in each of said six degrees of freedom. 
 
     
     
         15 . The flight control system of  claim 14  wherein said adjustable-pitch propellers are controlled by 2 of said 4 groups. 
     
     
         16 . The flight control system of  claim 9  wherein said vehicle further comprises at least two ducted thrust fans, each having an adjustable-pitch propeller and a plurality of directional vanes associated therewith, controlled, respectively by different ones of said groups. 
     
     
         17 . The flight control system of  claim 9  wherein a sum of the control power of all of said groups is greater than the control power required to maintain control of said vehicle. 
     
     
         18 . The flight control system of  claim 16  wherein the adjustable-pitch propellers of both the ducted lift fans and ducted thrust fans are controlled by two of said four groups. 
     
     
         19 . The flight control system of  claim 9  wherein n=4 and n-1/n control power is sufficient to maintain control of the vehicle. 
     
     
         20 . A flight control system for a VTOL vehicle comprising four groups of controls, each group comprising inputs relating to six degrees of freedom of the vehicle, at least one control computer subsystem and a plurality of actuators; each group utilizing 25% of required flight control power for the vehicle. 
     
     
         21 . The flight control system of  claim 20  wherein the vehicle comprises at least a pair of ducted lift fans, a pair of ducted thrust fans, and a plurality of directional vanes associated with each of said pair of ducted lift fans and said pair of ducted thrust fans. 
     
     
         22 . The flight control system of  claim 21  wherein each group controls 25% of said plurality of directional vanes. 
     
     
         23 . The flight control system of  claim 21  wherein each of said ducted lift fans and each of said thrust fans includes a variable-pitch propeller, and wherein adjustment of all of said variable-pitch propellers is evenly divided between the four groups. 
     
     
         24 . The flight control system of  claim 21  wherein each of said ducted lift fans and each of said thrust fans includes a variable-pitch propeller, and wherein adjustment of all of said variable-pitch propellers is evenly divided between at least two of said four groups. 
     
     
         25 . A method of controlling the flight of a VTOL vehicle comprising:
 dividing a flight control system into n control groups; and   incorporating into each control group a plurality of inputs, at least one control computer subsystem and a plurality of actuators such that each control group provides approximately 1/n of required control power, and wherein each group contributes to control of the vehicle in six degrees of freedom.