Guarding a Non-Maneuverable TranslatingLine with an Attached Defender

In this paper we consider a target-guarding differential game where the defender must protect a linearly translating line segment by intercepting an attacker who tries to reach it. In contrast to common target-guarding problems, we assume that the defender is attached to the target and moves along. This assumption affects the defender’s maximum speed in an inertial frame, which depends on the target’s direction of motion. Zero-sum differential game of degree for both the attacker-win and defender-win scenarios are studied. The payoff is defined as the distance between the two agents at the time of game termination. We derive the equilibrium strategies and the Value function by leveraging the solution for the infinite-length target scenario. The zero-level set of this Value function provides the barrier surface that divides the state space into defender-win and attacker-win regions. We present simulation results to demonstrate the theoretical results.