Defense for Displacement Attacks on Distributed Formation Control Systems

As an effective multi-agent system (MAS) control method, formation control is widely used in uncrewed systems, such as uncrewed surface/underwater/aerial vehicles and spacecrafts. However, the security issues of formation control have received little attention. Compared with traditional industry systems (such as smart grids or intelligence appliances), designing countermeasure approaches for distributed formation systems under attacks has several challenges, such as limited local information, robot mobility, and a chain reaction of attacks. In this paper, based on a classical formation control law on a group of robots, we concentrate on maintaining an acceptable formation performance under Man-in-the-Middle-based (MITM-based) displacement attacks. The MITM-based displacement attacks can utilize the property of formation maintenance and hijack the whole robot group. We propose two kinds of novel countermeasure approaches. An active approach, which is named the comparison-based identification and elimination (CIE) algorithm, can identify attack messages and calculate estimate values to replace attack messages based on local information. A passive approach can tolerate attack effects by designing a task priority adjustment (TPA) controller. The TPA controller can gradually adjust the formation maintenance priority to degrade attack effects. Simulation with several nonholonomic differentially driven mobile robots is conducted, and results show that our schemes can significantly decrease the impact of constant and time-varying attacks.