Event-triggered formation tracking control of nonholonomic mobile robots without velocity measurements

Abstract This paper investigates an event-triggered formation tracking problem of nonholonomic mobile robots in a leader’s coordinate frame. The proposed control protocol can be implemented in directed sensor networks based on only relative information detected by onboard sensors of mobile robots. A novel observer is proposed, and by virtue of it, neither velocity measurements nor communication among robots is required. Furthermore, by introducing a super-twisting sliding mode differentiator, the convergence of estimation errors is no longer dependent on the convergence of system states, which makes it possible to adopt an event-triggered mechanism, by which the continuous update of control command is avoided and Zeno behavior is excluded. Finally, simulations illustrate the effectiveness of our control protocol.