Design and experimental evaluation of global sliding mode controller

The paper considered real-life applicability of global sliding mode controller (GSMCr) for nonlinear uncertain tank process. In a typical sliding mode control (SMC), robustness during reaching phase is not guaranteed. The proposed strategy interrogates the reaching phase, mitigates chattering, and overcomes external disturbances. The control law input has been formulated based on minimum and maximum values of estimated system parameters to alleviate chattering effect. Direct Lyapunov function confirms the stability condition. Proposed method has been designed and implemented to realise a smooth sliding manifold. The efficacy is demonstrated experimentally for laboratory single input single output level control system as well as second-order uncertain servo plant via the simulation tests. The reported results affirm the superiority of control method over typical SMC in terms of speed of process and time-domain specifications. The real-time implementation guarantees the robustness in terms of multi-level set-point changes, parameter variations and disturbance rejection. It shows 33.33% improvements in process variable deviations and 10.71% reduction in chattering as compared to conventional SMC. The simulation example shows 8.51% chattering reduction over prevalent SMC. Copyright © 2023 Inderscience Enterprises Ltd.