“…As some examples in other references, in Yu et al [2], a new sliding surface is proposed as for and , and it is annalistically shown that for any initial condition , system state will converge to zero in finite time. As another example, in [3,4] a sliding surface is defined as and the authors in [3,4] have done a lot of efforts to analytically show that in sliding phase of system (when ), the error will converge to zero in a finite time like .…”