Sliding mode approach for formation control of multi-agent systems with unknown nonlinear interactions

This paper proposes nonlinear control approaches to solve a leader-follower formation of multi-agent system with unknown nonlinear interactions. Two distributed sliding mode control approaches are suggested here to track a leader in a desired formation with compensating unknown nonlinear terms. The nonlinear interaction terms can appear in multi-agent systems due to physical connections or cooperation between agents. Also the uncertainty in coefficient of control input is considered. Super twist algorithm is suggested for investigating this problem. Some Lyapunov functions are modified and employed to prove maintaining the formation of group, using the proposed sliding mode controllers. A simulation result for slung load transporting with quad-rotors is presented to demonstrate the capability of the proposed approaches.