Free chattering sliding mode control with adaptive algorithm for ground moving target tracking

In this paper a free chattering sliding mode is proposed to generate the guidance law, in order to achieve the tracking of the ground moving target while an adaptive method is improved to deal with uncertainty. Sliding mode control is low sensitivity to planet parameter variations and uncertainties which eliminates the necessity of exact modeling. One of the major advantages of the proposed controller lies that its implementation only requires online estimation without the knowledge of bounds on system uncertainties. At first, the error dynamic of the tracking problem is described based on the range between unmanned aerial vehicle and ground moving target. Then, the nonlinear guidance law is proposed based on adaptive second order sliding mode control to achieve robustness, invariance and finite time tracking, and the chattering effect has been eliminated. Adaptive estimation is used to improve the command state generation and deal with the uncertainty of the target estimation. Closed loop stability is proved via Lyapunov analysis. Moreover, the accurate tracking of the target state has been achieved in the presence of the uncertainty which has been demonstrated in the simulation section.