An adaptive finite-time formation tracking control approach is proposed for multiple unmanned aerial vehicle (UAV) system with quantized input signals in this paper. The UAVs are described by nonholonomic kinematic model and autopilot model with uncertainties. An enhanced hysteretic quantizer is introduced to avoid chattering, and some restrictions are released by using a new quantization decomposition method. Based on backstepping technique and finite-time Lyapunov stability theory, the adaptive finite-time controller is designed for the trajectory tracking of the multi-UAV formation. The nonholonomic constraints are solved by a transverse function. A transformation is introduced to the control input signals to eliminate the quantization effect. Stability analysis proves that the tracking errors can converge to a small neighborhood of the origin within finite time and all the closed-loop signals are semiglobally finite-time bounded. The effectiveness of the proposed control approach is validated by simulation and experiment.

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This paper studies the distributed output feedback control problem for formation tracking of multi-agent systems with both quantized control and measurement signals. The control and measurement signals are processed by hysteretic quantizers to avoid chattering. The agent dynamics are described by a nonlinear uncertain model with immeasurable states, unmodeled dynamics, and disturbances. To estimate the immeasurable states and solve uncertainties, state observers are designed by utilizing dynamic highgain technique. With the state observer, a distributed output feedback controller is developed for multi-agent systems by using the quantized measurements of the relative positions of the agents and the quantization effect on the control system is eliminated. The stability analysis proves that the proposed controller can achieve the multi-agent formation tracking, and all the closed-loop signals are bounded. By using the MATLAB/Simulink software, experimental results verifies the effectiveness of the proposed control scheme.INDEX TERMS Multi-agent system, formation tracking, hysteretic quantizer, output feedback control.

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