Anti-Disturbance Switching Control for Silicon Single Crystal Growth Systems Under Unmeasured States

In this article, the anti-disturbance switching control approach is proposed for silicon single crystal growth systems with unmeasured states. Initially, the silicon single crystal growth systems are modeled by using the geometrical models of meniscus section, hydrodynamic and heat transfer process of silicon single crystal growth. Since numerous unmeasurable state variables exist in systems and the growth equipments are affected by external and internal disturbances, consideration is given to employing the output feedback control scheme and disturbance observer method in the construction of the anti-disturbance switching controller. Meanwhile, considering the high accuracy of linear systems at equilibrium points, the silicon single crystal growth systems are divided into multiple subsystems using switching control method, that is, multiple equilibrium points are set to enable the systems to switch between different subsystem models, thereby the precision of silicon single crystal growth systems has been improved. Then, using the multiple Lyapunov function method and linear matrix inequality technique, the exponential stability of silicon single crystal growth systems is ensured with the $\boldsymbol {H_{\infty }}$ performance. Finally, the feasibility of designed switching anti-disturbance output feedback control method is verified through actual parameters of silicon single crystal growth systems.