Design And Analysis Of A Novel Liquid Suspension Hybird Drive Multi-DOF PM Motor

With the rapid development of modern industry and manufacturing,the traditional multi-degree-of-freedom actuators can not meet the demand of applications due to its complex structure,high control difficulty,low positioning precision and the disadvantage of large energy consumption.The emergence of the multi-degree-of-freedom permanent magnet motor solves these problems,and makes people have a new understanding of the multi-degree-of-freedom device.In this paper,the advantages of various multi-degree-offreedom permanent magnet motors are summarized,and a novel type of liquid suspension hybrid drive multi-degree-of-freedom permanent magnet motor is proposed.This motor adopts an innovative liquid suspension structure,which reduces the friction loss when using the mechanical bearing for connection.The hybrid drive mode of the motor is used to guarantee satisfied positioning accuracy and stability.The appearance of the liquid suspension hybrid drive multi-degree-of-freedom permanent magnet motor provides a new idea for the development of multi-degree-of-freedom permanent magnet motor.In this paper,the electromagnetic system and the fluid characteristics of the oil film of the motor are mainly analyzed in detail.Firsty,the structure parameters and working principle of this motor are introduced.The motor model is established with the finite element analysis software,and the magnetic field of permanent magnets and the distribution of air gap flux density are analyzed.The torque characteristics' curves of the motor are calculated.The power strategy of the motor for spin rotation is formulated,and the effects of different quantity of stator coils on the deflection torque of the motor are compared and analyzed.Secondly,in order to compare with the finite element method,the analytical method is used to model and analyze the motor.The magnetic field model of the motor is established by solving the Laplace equation in the spherical coordinate system,and the spacial distribution of the air gap magnetic field of the motor's permanent magnet is calculated.The motor's torque model is derived by using the Lorenz force method,and the torque characteristics of the motor are obtained.The inhomogeneous distribution of flux density in the eccentric condition is analyzed using the analytical method.Combined with the finite element analysis software,the distribution of the radial electromagnetic force in the case of eccentric operation of the motor are calculated.At last,the physical properties and mathematical model of the oil film are analyzed.By using the computational fluid dynamics simulation software,the liquid oil film pressure distributionand drag torque of oil film on the rotor are analyzed and calculated in the condition of different eccentricity and rotational speeds.The work done in this paper proves the rationality of the motor structure design,and provides the theory and data support for optimization design and control system design of the motor.