In this paper, a generalised regular form for sliding mode control is proposed for a class of nonlinear systems. A novel approach to design nonlinear sliding surfaces based on this generalised regular form is presented using global implicit function theory such that the resulting sliding motion is globally asymptotically stable. Sliding mode controllers are designed to drive the system to the sliding surface and maintain a sliding motion thereafter. Both matched and mismatched uncertainties are considered. Then, the developed results are applied to the tracking control of a two wheeled mobile robot. The model-based tracking problem under study is initially transferred to a stabilization problem. Simulation results demonstrate that the tracking error system is globally asymptotically stable even in the presence of both matched and mismatched uncertainties.