Fixed-Time Command Filter Fuzzy Adaptive Formation Control for Nonholonomic Multirobot Systems With Unknown Dead-Zones

In this paper, the problem of fuzzy adaptive fixed-time formation control is studied for nonholonomic multirobot systems (NMRSs) subject to unknown dead-zones and multiple constraints. Fuzzy logic systems (FLSs) are used to identify nonlinear NMRSs with uncertain dynamics, and then adaptive technique are utilized to compensate for unknown dead-zones parameters. By combining prescribed performance control (PPC) method, the transient and steady-state performances of the NMRSs are guaranteed, thereby further achieving collision avoidance and connectivity maintenance. On this basis, in order to achieve fixed-time convergence of formation tracking errors and eliminate the effect of unknown dead-zones, a novel adaptive robust fixed-time formation control (FxTFC) strategy is further proposed by introducing fixed-time stability theory and command filter technique. It can avoid the output shafts do not acting for a short time period when the input shafts turn rapidly, ensure the nonlinear NMRSs are fixed-time stable and all signals are bounded, which can be proved by constructing the Barrier Lyapunov Functions (BLFs). In the end, the simulation studies are carried out to show the efficacy of the developed robust FxTFC strategy. The result is that even if there are actuator dead-zones among each robot, formation tracking can also be achieved in fixed-time.