In this paper, we propose a distributed prescribed performance formation tracking control method for unknown Euler-Lagrange systems subject to input amplitude constraints. We address the challenge of maintaining formation tracking within predefined performance bounds when the agents' inputs are subject to saturation. This is achieved by designing a distributed virtual velocity reference modification mechanism, which modifies the desired velocity reference of each agent whenever saturation occurs. We establish sufficient feasibility conditions for the input constraints that ensure prescribed performance formation tracking of the desired trajectory and guarantee the boundedness of all closed-loop signals. Simulations on a team of underwater vehicles validate the method's effectiveness.
Keywords: constrained control; distributed control; formation control; nonlinear systems; robust control; uncertain systems.