Robust Distributed Formation of UAV Swarms with Collision Avoidance under Control Signal Nonlinearity and Unknown Input of Leader

This paper considers the formation control of unmanned aerial vehicles (UAVs) along with collision avoidance under nonlinear control signals and unknown input of the leader. First, the problem of estimation of input of the leader by the followers has been addressed. This input estimation is needed to use a compensation signal in the formation controller by the follower agents. To solve the problem, we have applied a distributed estimator for follower UAVs to estimate the time-varying leader’s input, which is then used in the formation controller. Second, a robust leader-following formation control approach under directed graphs by application of the cooperative input estimator has been revealed. While designing the formation controller, the input nonlinearities, which are always present in the UAVs due to actuator and controller responses, are also investigated. The problem of input nonlinearity has been dealt with by merging the nonlinearity in the communication topology of UAV nodes and the LPV treatment. The stability analyses of the estimator and controller are provided, and design conditions are carried out with the help of Lyapunov function-based approaches. Simulation results are provided to verify the theoretical and mathematical work for estimation and formation problems.