Radial position control of a magnetically suspended rotor system in a direct-driven spindle using inverse system scheme

Abstract

Direct-driven spindles have no mechanical transmission trains and gears, and are the key actuators for computerized numerical control machine tools. These magnetically suspended rotor systems are required to provide fast response and high precision. However, these systems are non-linear and strongly coupled. The traditional proportional, integral, derivative (PID) control method has been widely used for such systems owing to its relative simple realization. However, the tracking, disturbance rejection and robustness properties of the controlled plant may not be satisfied. To solve these problems, this paper presents a decoupling control strategy based on an inverse system scheme and combines it with the internal model control method to guarantee system robustness to the parameter uncertainty and external disturbance. By introducing an inversion of the magnetically suspended rotor system into the original system, a new pseudolinear system is developed. It can be shown that this addition effectively eliminates the influence of the unmodelled dynamics, and improve the accuracy and robustness of the whole system. The simulation and experimental results show that when compared with the traditional control scheme, the proposed control scheme provides good decoupling and robustness performance for the magnetically suspended rotor system in different operating conditions.

Radial position control for magnetically suspended high‐speed flywheel energy storage system with inverse system method and extended 2‐DOF PID controller

“…Feedback linearisation decoupling methods mainly include inverse system method [11][12][13][14][15][16][17][18][19] and differential geometry method [20,21]. Differential geometry method requires that the mathematical model of controlled plant can be described as an affine, non-linear form.…”

Sliding mode variable structure control strategy of bearingless induction motor based on inverse system decoupling

“…[6][7][8][9][10]. The bearingless motor is a new type of AC motor that is suitable for highspeed operations, which is proposed based on the comparability in structure between the magnetic bearing and the stator of a conventional AC motor [11][12][13][14][15]. Apart from some special bearingless motors with single windings [16,17], in a common bearingless motor, there are two sets of windings in the stator slots, including a set of torque winding (with pole-pair number p 1 and current angular frequency ω 1 ) and a set of suspension winding (with pole-pair number p 2 and current angular frequency ω 2 ) [18][19][20][21][22].…”

“…When the suspension control magnetic field is superimposed on the original rotating magnetic field of the AC motor, the balance and symmetry of the air gap magnetic field is broken, the air gap magnetic field in some parts of the air gap area is enhanced, and the air gap in the space-symmetric area is weakened; then, a radial electromagnetic force is produced in the enhancement direction of the air gap magnetic field. When the two sets of windings meet the 'p 2 = p 1 ± 1 ' and 'ω 2 = ω 1 ' conditions, the resultant radial force is controllable both in amplitude and in direction [12][13][14][15][16][17][18][19][20][21][22][25][26][27]. The controllable radial force is the so-called controllable magnetic a Correspondence to: Wesnshao Bu.…”

Precise control of a four degree-of-freedom permanent magnet biased active magnetic bearing system in a magnetically suspended direct-driven spindle using neural network inverse scheme

“…Additionally, the inverse system scheme is simple, intuitive, and relatively simple to carry out. In [22], the inverse system scheme is used for the radial position control of a magnetically suspended rotor system in a direct-driven spindle. However, attributed to the complexity of the magnetically suspended rotor system in a direct-driven spindle, its mathematical model will not be known precisely.…”