  This paper presents the distributed pinning consensus solution for nonlinear
positive multi-agent systems with nonlinear control input by applying
observer-based control protocols. The network topology is considered as a
directed and fully connected structure. By considering sector input
nonlinearities and various forms of topologies, two kinds of state observers
involving standard observer and distributed pinning observer are presented for
each regarded nonlinear agent by applying a novel analysis directly dealing
with the nonlinear input and nonlinear system dynamics. The measured local
output detail outlines the first observer, and the other observer is achieved
via the corresponding output detail of its adjacent agents. Based on further
observed state details, a distributed pinning observer-based strategy is
derived for the leader-follower non-negative global consensus of the nonlinear
positive multi-agent system. Additionally, two multi-step algorithms are
proposed to set up the observer gains and each protocol criterion. Performance
evaluations are provided to confirm the proposed control method and illustrate
the effectiveness of the derived non-negative consensus observer-based
protocols.
