Truly Distributed Finite-Time Attitude Formation-Containment Control for Networked Uncertain Rigid Spacecraft

Fixed-time time-varying output formation-containment control of heterogeneous general multi-agent systems

This work investigates fixed-time time-varying output formation-containment control of heterogeneous general multi-agent systems, which comprises one virtual leader, multiple leaders, and followers. First, fixed-time nonlinear control law is constructed, such that leaders can achieve time-varying output formation in a finite time. Meanwhile, leaders can track the virtual leader's output trajectory. Next, two complete distributed adaptive fixed-time observers are designed aiming to recover a convex hull. This is key to control issue in this paper. Further, nonlinear control law is constructed for followers, such that followers can move into the convex hull formed by multiple leaders. Finally, two examples are provided to verify the feasibility of the theoretical results.

Distributed Adaptive Finite-Time Consensus for High-Order Multi-Agent Systems with Intermittent Communications under Switching Topologies

In this paper, a distributed adaptive finite-time consensus (FTC) control protocol for a high-order multi-agent system (MAS) with intermittent communications under switching topologies is proposed. Meanwhile, considering the problem of heterogeneous unknown nonlinearities and other uncertain disturbances, the adaptive neural network and the sliding mode control method are used to compensate the nonlinearity of each agent separately. The agents are homogeneous, so the system has symmetry. The switching topologies considered in this paper are asymmetric. Compared with consensus protocol for asymptotic convergence, simulation results show that the proposed method can effectively solve the presence of the nonlinear and accelerate the convergence speed of the system so that an FTC can be reached.

Adaptive Sliding Mode Attitude-Tracking Control of Spacecraft with Prescribed Time Performance

In this article, a novel finite-time attitude-tracking control scheme is proposed by using the prescribed performance control (PPC) method for the spacecraft system under the external disturbance and an uncertain inertia matrix. First, a novel polynomial finite-time performance function (FTPF) was used to avoid the complex calculation of exponential function from conventional FTPF. Then, a simpler error transformation was introduced to guarantee that the attitude-tracking error converges to a preselected region in prescribed time. Subsequently, a robust adaptive controller was proposed by using the backstepping method and the sliding mode control (SMC) technique. Unlike the existing attitude-tracking control results, the proposed PPC scheme guarantees the performance of spacecraft system under the static and transient conditions. Meanwhile, the state trajectory of system can be completely drawn into the designed sliding surface. The stability of the control scheme is proven rigorously by the Lyapunov’s theory of stability. Finally, the simulations show that the convergence rate and the convergence accuracy are better for the tracking errors of spacecraft system under the proposed control scheme.