Research On Improved Active Disturbance Rejection Decouping Control Of Six-pole Radialactive Magnetic Bearing

The development goal of China in manufacturing industry in the “Made in China 2025” action plan is proposed to build itself into a manufacturing power leading the development of the world’s manufacturing industry.Machine tools play a significant role in mechanical manufacturing,and high-precision and high-quality machine tools can meet the highest industrial needs of mechanical manufacturing.Traditional machine tools are supported by mechanical bearings,but mechanical bearings have problems such as large friction,low speed,and low precision.In order to achieve high precision and high efficiency of machine tools,an electric spindle supported by magnetic bearing came into being.The Maxwell force of magnetic bearings is generated by an energized coil or permanent magnet,and the rotor can maintain stable suspension under the control of Maxwell force.At present,traditional mechanical bearings have disadvantages such as low bearing capacity,high friction between stator and rotor,and high noise.Magnetic bearings,due to their rotor floating in the air during operation,have advantages such as no friction,low noise,and long service life,making up for the shortcomings of traditional mechanical bearings.At present,the magnetic bearing has developed a six-pole magnetic bearing driven by inverter.Compared with the traditional DC magnetic bearing,the magnetic bearing driven by inverter has smaller volume and lower maintenance cost.Due to its symmetrical space structure,the six-pole magnetic bearing has greater bearing capacity and higher space utilization ratio than the three-pole magnetic bearing.The inverter driven six-pole radial active magnetic bearing(AMB)is researched in this dissertation,and its working principle,structural parameter design,and decoupling control are theoretically analyzed and experimentally studied.The main completed work and achievements of the dissertation are as follows:(1)Firstly,the research background and significance of magnetic bearings are elaborated;According to the principle of magnetic bearing suspension force generation,controlled degrees of freedom,and other methods,magnetic bearings are classified and the characteristics of various types of magnetic bearings are elaborated;The application prospects of magnetic bearings based on the characteristics of different types of magnetic bearings are summarized;The development process of magnetic bearings both domestically and internationally in recent years are introduced;the research status of decoupling control technology for magnetic bearings are discussed;Finally,a summary is made on the future development trend of magnetic bearings.(2)The specific structure and working principle of the six-pole radial AMB are analyzed,and the suspension force model of the six-pole radial AMB using the Maxwell tensor method based on its structural characteristics are derived;A complete mathematical model is derived by combining the suspension force model with the rotor dynamics equation;The material and specific parameters of the rotor are selected based on the requirement of a radial bearing capacity of 200N;Finally,simulation verification is conducted on the selected specific structural parameters,and the simulation results showed that the relationship between the radial suspension force of the rotor,control current,and radial displacement met the design requirements.(3)An improved active disturbance rejection controller based on improved genetic algorithm is proposed to decouple the rotor and solve the coupling problem between the six-pole radial AMB rotors.Aiming at the problem of the decoupling effect of the traditional ADRC on the six-pole radial AMB,the parameters in the nonlinear extended state observer are optimized and modified by using the improved genetic algorithm,so as to improve the compensation accuracy and corresponding speed of the nonlinear extended state observer,and further improve the decoupling control effect of the improved ADRC on the six-pole radial AMB;Finally,a model is built in Matlab simulation software to verify the feasibility of using this method for rotor decoupling control between two degrees of freedom in a six-pole radial AMB system.(4)A corresponding digital control system is designed based on the nonlinear and strong coupling characteristics of the six-pole radial AMB;Firstly,the specific hardware components required,as well as the topology and functions of the main circuit boards,are introduced.Then,how to use software to achieve real-time control of the upper computer is introduced;Finally,an experimental platform is built and relevant rotor decoupling control experiments are conducted to validate the improved ADRC method based on improved genetic algorithm for magnetic bearings proposed in this dissertation.