United Technologies Corporation

Thomas H Lawrence

Phillip J Gold

John J Pawlowski

Philip A Jeffery

Joseph J Mankaukas

Christopher J Connolly

Matthew T Smith

A helicopter external cargo suspension system (12) has load sensors (19,20) at each suspension point for sensing the magnitude of a load (32) at each suspension point. A delay period (FIG. 6) is determined based on the magnitude of the load, and a load is released if one of the following failure modes occurs for a period which exceed the delay period: one of the suspension points is unloaded, the magnitude of the load exceeds a maximum threshold magnitude, or if the distribution of the load, as indicated by the difference in magnitude at each suspension point, exceeds a difference threshold magnitude. If the magnitude of the load is below a minimum threshold magnitude, the load will be carried by one of the suspension points in response to a failure of the other suspension points. Alternatively, the load information is converted from crisp values to fuzzy inputs (700) wherein the detected values are fuzzified by assigning a membership weight at discrete points or segments on a normalized scale; a new mode fuzzy output (707) is provided by applying a compositional rule of inference (705) across each fuzzy input (702) and a composite mode selection rule base (710), the new mode fuzzy output (707) is converted into a crisp output by taking the weighted sum of the membership weight at each point on the normalized scale in excess of a threshold value (712), and new mode is determined by comparing the new mode crisp output to a set of new mode membership ranges (FIGS. 8e and 9e).

Automatic release of a load from a helicopter external cargo suspension

Control law system for the collective axis, as well as pitch and roll axes, of an X-Wing aircraft and for the pneumatic valving controlling circulation control blowing for the rotor. As to the collective axis, the system gives the pilot single-lever direct lift control and insures that maximum cyclic blowing control power is available in transition. Angle-of-attach de-coupling is provided in rotary wing flight, and mechanical collective is used to augment pneumatic roll control when appropriate. Automatic gain variations with airspeed and rotor speed are provided, so a unitary set of control laws works in all three X-Wing flight modes. As to pitch and roll axes, the system produces essentially the same aircraft response regardless of flight mode or condition. Undesirable cross-couplings are compensated for in a manner unnoticeable to the pilot without requiring pilot action, as flight mode or condition is changed. A hub moment feedback scheme is implemented, utilizing a P+I controller, significantly improving bandwidth. Limits protect aircraft structure from inadvertent damage. As to pneumatic valving, the system automatically provides the pressure required at each valve azimuth location, as dictated by collective, cyclic and higher harmonic blowing commands. Variations in the required control phase angle are automatically introduced, and variations in plenum pressure are compensated for. The required switching for leading, trailing and dual edge blowing is automated, using a simple table look-up procedure. Non-linearities due to valve characteristics of circulation control lift are linearized by map look-ups.

Control law system for X-Wing aircraft

A circulation control rotor system in which butterfly valves (44, 46) control the flow of compressed air from a plenum chamber (40) to the rotor blades (14). Each has an actuator (48, 52) positioning the valve in accordance with a control input and in which a spring loaded averaging linkage (120) between adjacent valves around a plenum chamber circumference acts to position the valve at an average position of the two adjacent valves if a fault in the actuator or within its control or power system should develop. Should such a fault develop, as determined by a comparison of actual valve position with command position, the faulty valve's actuator is shut down.

Growing community of inventors

Derby, CT, United States of America

Thomas H Lawrence