A new velocity observer for a class of double integrator dynamics

This paper proposes a new velocity observer for a class of nonlinear double integrator dynamics. Mainly, supposing that the nonlinear terms and control input in the double integrator are bounded, we design a simple observer that is structured only with a feedback of estimation position error. Unlike to existing works that mostly have been developed from super-twisting algorithm, this paper does not use any sign function in the velocity observer. Thus, the overall structure of the proposed observer is much simple than existing approaches, while the desired convergence is analytically ensured. From numerical simulation, the validity of the proposed method is illustrated.