Engineering topics

Rajan, N.

Publications and source records attributed to Rajan, N..

22 records · Page 2

NASA NTRS1983

Optimal feedback strategies for pursuit-evasion and interception in a plane

Variable-speed pursuit-evasion and interception for two aircraft moving in a horizontal plane are analyzed in terms of a coordinate frame fixed in the plane at termination. Each participant's optimal motion can be represented by extremal trajectory maps. These maps are used to discuss sub-optimal approximations that are independent of the other participant. A method of constructing sections of the barrier, dispersal, and control-level surfaces and thus determining feedback strategies is described. Some examples are shown for pursuit-evasion and the minimum-time interception of a straight-flying target.

Rajan, N.↗

NASA NTRS1983

Computation of optimal feedback strategies for interception in a horizontal plane

The problem of minimum-time interception of a target moving in a horizontal plane is studied. The target may fly a trajectory that is known at the start of the interception or try to evade the intercepting aircraft. The interceptor's optimal motion is described independently of the target in terms of an extremal trajectory map. The latter is used to develop guidelines for suboptimal approximations to the extremals. A method of constructing the feedback solution by drawing isochrones (constant minimum-time loci) is developed. Sections of the feedback solution for the interception of a straight-flying target are presented, and the construction of an isochrone for the interception of an actively evading target is demonstrated.

Rajan, N.↗

NASA NTRS1983

Stress testing of digital flight-control system software

A technique for dynamically testing digital flight-control system software on a module-by-module basis is described. Each test module is repetitively executed faster than real-time with an exhaustive input sequence. Outputs of the test module are compared with outputs generated by an alternate, simpler implementation for the same input data. Discrepancies between the two sets of output indicate the possible presence of a software error. The results of an implementation of this technique in the Digital Flight-Control System Software Verification Laboratory are discussed.

Rajan, N.↗

NASA NTRS1982

Barriers and dispersal surfaces in minimum-time interception

Minimum time interception of a target moving in a horizontal plane is analyzed as a one-player differential game. Dispersal points and points on the barrier are located for a class of pursuit evasion and interception problems. These points are determined by constructing cross sections of the isochrones and hence obtaining the barrier, dispersal, and control level surfaces. The game solution maps the controls as a function of the state within the capture region.

Rajan, N.↗