“…the position) is measured, SMCPE may encounter the risk of large estimation errors which will result in a degraded performance. On the other hand, to keep away from the risk of estimating VHOS in SMCPE, the design of an adaptive sliding mode controller (ASMC) with a time-varying switching gain dynamically compensating for the perturbation was introduced (Cong et al, 2012;Fei et al, 2012;Huang et al, 2008;Lee and Utkin, 2007;Li and Xu, 2010;Mahmoodabadi et al, 2014;Plestan et al, 2010;Utkin, 1992;Utkin and Poznyak, 2013b;Wheeler et al, 1998). For the ASMC designs, the system response to the perturbation is relatively slow; moreover, even though the overestimation is avoided somehow, the chattering phenomenon is still observed.…”