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Introduction
The sliding mode control (SMC), developed in the Soviet Union in the mid-1950s,[1] is one of the most robust control methods available today and has received much attention in recent decades. There are error signals in the SMC input gain while the output is a controller signal for the system. However, the SMC is a powerful technique that drives the system state to a custom-built and then a constraint state of a surface.[2] The system generated on this surface is known as the sliding mode, but the SMC method must ensure that the system works stably on this surface. The variable structure control (VSC) framework[1] can be applied, of using the switching method. In every state, the sliding mode will adapt to outside disturbances within finite-time convergent and can be described by a reducing order equation. The most important aspect here is the chosen sliding surface technique. In this article, we propose the use of a specified proportional-integral-derivative (PID) controller intended to solve the chattering problem, in which [Formula Omitted: See PDF] is the state vector, [Formula Omitted: See PDF] is the input signal, [Formula Omitted: See PDF] is the sliding surface, and the definitions of s are manifold. The motion on the discontinuous surface, [Formula Omitted: See PDF], is the so-called sliding mode motion,[1] which is revealed by high-frequency switching. The disadvantages of the SMC method are resulted from its chattering and reaching phase.
To function without contacts or frictions, the magnetic suspension offers the potential for many applications in typical electromechanical products, including the turbine engine and flywheel, as well as other practical applications such as computer numerical control (CNC) machines and the artificial heart pump. In the artificial heart pump, the device assists the left ventricular chamber to maintain the rate of the blood flow.[3],[4] The suspension structure includes two magnets, as shown in [Figure 1], one of which is sensorless but with a measurable distance.[5] Our task is to generate a signal for controlling the internal rotor to a predetermined position, within an external disturbance rotor that continues to guide the desired set-up position. The suspension of the active magnetic bearing system (AMBs) generates an electromagnetic field to ensure non-contact between the stationary...