Sliding mode observer for nonlinear mechanical systems subject to nonsmooth impacts

In control mechanical systems design, the velocity signal is not always available and may be corrupted by noise. It is therefore necessary to estimate it in order to construct the control law. This paper proposes a new sliding mode observer for nonlinear mechanical systems subject to nonsmooth impacts. The estimation of the velocity signal is derived from only position measurements. The proposed observer ensures an asymptotic velocity observation also in presence of non-smooth impacts. Excellent simulation results are included to show the effectiveness of the proposed approach.