A Combined Intrusion Strategy Based on Apollonius Circle for Multiple Mobile Robots in Attack-Defense Scenario

The multi-agent attack-defense game has become a hot issue in recent years. However, it is still a challenge to design an efficient intrusion strategy when the intruder has a limited detection range. In this letter, a combined intrusion strategy based on Apollonius circle is proposed, which decomposes the complex intrusion task into several basic actions, including target attack action, defense breakthrough action, and pursuit-escape action. One of these three actions will be adopted by the intruder according to the hazard of the surrounding area. The application of the Apollonius circle theorem enhances the intruder's ability to effectively utilize available information and accurately assesses the situation. By applying the theorem, the intruder can determine potential risks associated with each direction of movement and subsequently partition the surrounding area into safe and hazardous zones. The intruder will advance directly toward the target if no hazardous zone obstructs its path. Conversely, if the hazardous zone exists yet safe pathways are available, the intruder will navigate around the defenders. In the absence of safe zones, the intruder will retreat to preserve its survival. This combined intrusion strategy simplifies the complex decision-making process and realizes the rapid response of the intruder to the environment. Extensive simulations validate the combined intrusion strategy's feasibility and effectiveness, and further physical experimental results confirm that the strategy has application potential.