Defining maximum safe maneuvering authority in 3D space required for autonomous integrated conflict resolution

Abstract

To maintain separation with other traffic, terrain, threats and special use airspace independent of control link availability, UAVs require the capability of autonomous conflict detection and resolution. In previous research it has been illustrated how conflict probing provides the basis for a framework to integrate the results from multiple conflict prediction functions and how conflict probing can be used to find two-dimensional resolution maneuvers. Conflict resolution should be able to use the full performance capabilities of the UAV, rather than command standard resolution maneuvers designed to accommodate the worst performing class of UAVs. The available 3D space for conflict resolution can be maximized by combining vertical and lateral maneuvers. This requires integrated control authority allocation and envelope protection functionality, taking into account the effect of lateral maneuvering on the vertical performance and load factor margin. The maximum safe maneuvering space should also utilize the ability to convert the available speed margin relative to Vmin or Vmax (excess kinetic energy) into altitude (potential energy). For humans it is almost impossible to maximize the maneuvering performance in this way without violating one or more maneuvering constraints such as angle of attack, stall speed, load factor and bank angle. The goal of the current research is to develop an autonomous conflict resolution system which uses (well) balanced lateral and vertical maneuver authorities, and if needed, can safely utilize the most aggressive possible vehicle maneuver capability. This paper discusses an approach to provide integrated vertical and lateral airplane maneuver authority allocation and envelope protection functions. These functions have been implemented in the Total Energy Control System / Total Heading Control System (TECS/THCS) design to generate example time responses of single and combined vertical and lateral maneuvers, including energy exchange (“zoom”) maneuvers. The methodology also provides for 3D end-state prediction and display on an enhanced SVS PFD. It is also illustrated how information about the maximum safe maneuvering authority is integrated into the conflict prevention/resolution function.