For the quasi sliding mode tracking control of a class of uncertain nonlinear systems with unknown control
gain, after analyzing the relationship between tracking error and sliding variable and using the idea of BIBO stability, the
boundedness of the steady-state error is derived when using Slotine form conventional sliding surface and conventional
integral sliding surface, respectively. Compared with known boundedness of steady-state error computed by using current
methods, the boundedness of steady-state error derived with the proposed method is more accuracy. Furthermore, by
specifying the tracking error that is required, an appropriate saturation function to eliminate chattering is designed.
Simulations results show the effectiveness of the proposed method.