No abstract

The unbalanced force on the active magnetic bearing (AMB) rotor system is the main reason of system vibrations, which always have periodic repetitive characteristics. However, the closed-loop feedback control system (CFCS) is difficult to achieve effective control of these repetitive problems. In this paper, we firstly analyzed the synchronous vibration by taking AMB rotor mass imbalance as an example. Then, we proposed a model-free control (MFC) method based on the Newton-type ILC algorithm, and the key of this MFC is to use a partial derivative (P-D) of the output with respect to the input. The simplicity of this algorithm lies in that and the P-D is calculated by only using the input and output (I/O) data of the system and then used to adjust the ILC gain. Subsequently, we proposed a parallel plug-in control scheme based on existing AMB control system to suppress synchronous vibration. Finally, we carried out the simulation and experiment to research the control method mentioned in this paper. The results show that the MFC has a good control effect on AMB synchronous vibration. Notably, this MFC for synchronous vibration has the advantages of being without system model, simple design and good portability, and can provide theoretical and experimental basis for the application of AMB in high precision and high speed fields.INDEX TERMS Active magnetic bearing, synchronous vibration, model-free, iterative learning control parallel control scheme.

Active control is one of the most important advantages of active magnetic bearing (AMB), and also can be used to suppress the imbalance of AMB rotor system (AMB-RS). This paper aims at dealing with periodic vibration problem caused by unbalanced force existing in AMB-RS as the rotor spins. Firstly, with the advantages of iterative learning control (ILC) over repetitive problems, a novel ILC algorithm based on the system information of the iteration before last iteration is put forward to achieve parallel computing of real-time control, real-time acquisition and signal extraction in AMB digital control system (DCS). Then, two compound control modes are proposed on the basis of AMB closed-loop feedback control system (CFCS), one is a parallel compound control mode (PCCM) that is used to achieve unbalance compensation, the other one is a serial compound control mode (SCCM) that is used to achieve automatic balance, and corresponding compound control systems are designed on the basis of an AMB experimental system. Finally, numerical simulation and experimental research are carried out, and the results show that the control methods proposed in this paper have significant control effect on the periodic vibrations produced by the unbalanced force of AMB-RS. Therefore, the research achievements can provide theoretical references and experimental basis for the further application of AMB in the high-precision and high-speed fields.INDEX TERMS Active magnetic bearing rotor system (AMB-RS), iterative learning control (ILC), parallel compound control mode (PCCM), serial compound control mode (SCCM), unbalance compensation, automatic balance.