Distributed Control of Nonlinear Systems With Unknown Time-Varying Control Coefficients: A Novel Nussbaum Function Approach.

In this article, distributed control of uncertain multiagent systems (MAS) with completely unknown nonlinearities, unknown time-varying control coefficients, and multiple unknown control directions is investigated. First, a new theorem with a series of novel Nussbaum functions are presented, which solve the outstanding problem in control of nonlinear systems with unknown time-varying control coefficients and unknown signs. Second, global consensus of MAS with unknown time-varying control coefficients and unknown system nonlinearities under directed graph is first achieved, and the transient tracking performance is also guaranteed. Third, a novel filter is proposed for each agent which does not require a prior knowledge of time derivative of leader. Finally, simulation results show the effectiveness of the proposed control schemes.