Advanced precision tracking control for permanent magnet linear synchronous motors utilizing a novel global dynamic fractional order sliding mode

This paper proposes a novel dynamic fractional order super-twisting terminal sliding mode control method aimed at suppressing the effects of undesired nonlinear dynamics, unstructured uncertainties, parameter mismatch and disturbance load on the PMLSM system performance, realizing high-precision tracking control with strong robustness. Firstly, a dynamic model of the system is developed, taking into account nonlinear friction and uncertainty. Then, combining the principles of fractional order and terminal sliding mode control, using the exponential function with tracking error as the independent variable as the control gain of the fractional order component, the fractional-order dynamic terminal sliding mode manifold is proposed, which achieves rapid convergence and a smooth transition process. Meanwhile, to address complex uncertainties of the system, a dynamic super-twisting algorithm, grounded in Lyapunov theory, is formulated. This algorithm allows for global dynamic adjustment and precise compensation for uncertainties and disturbances. Finally, simulation and experimental results demonstrate that the proposed method outperforms existing controllers in terms of tracking accuracy and robustness.