Predefined time fault tolerant scaled cooperative control for multiple UAVs with prescribed performance

This article address the issue of practical predefined time (PT) scaled cooperative control (SCC) for multiple quad-rotor unmanned aerial vehicles (UAVs) with unknown nonlinear dynamics, unknown disturbances, and non-affine nonlinear actuator faults. A practical PT stable criterion for nonlinear systems is proposed, and the concept of practical PT SCC for multiple UAVs is introduced. All these provide theoretical bases for our research. PT prescribed performance control (PPC) technology is utilized to ensure performance constraints on scaled cooperative errors. Meanwhile, a practical PT command filter is provided to avoid the computational complexity inherent in the traditional backstepping method. Subsequently, a distributed practical PT SCC scheme with PT prescribed performance is developed by employing PT control method, backstepping recursive algorithm, and neural networks (NNs) approximation technology. The presented control strategy can guarantee that the multiple UAVs achieve the desired PT SCC objective, scaled cooperative errors satisfy anticipated transient and steady-state performances, all signals in the closed-loop systems are bounded, and all errors are driven to a small region around zero within the PT. Eventually, a simulation example is provided to verify the developed methodology.