This paper explores a robust μ-synthesis control scheme for structural resonance vibration suppression of high-speed rotor systems supported by active magnetic bearings (AMBs) in the magnetically suspended double-gimbal control moment gyro (MSDGCMG). The derivation of a nominal linearized model about an operating point was presented. Sine sweep test was conducted on each component of AMB control system to obtain parameter variations and high-frequency unmodeled dynamics, including the structural resonance modes. A fictitious uncertainty block was introduced to represent the performance requirements for the augmented system. Finally, D-K iteration procedure was employed to solve the robust μ-controller. Rotor run-up experiments on the originally developed MSDGCMG prototype show that the designed μ-controller has a good performance for vibration rejection of structural resonance mode with the excitation of coupling torques. Further investigations indicate that the proposed method can also ensure the robust stability and performance of high-speed rotor system subject to the reaction of a large gyro torque.

AMB Vibration Control for Structural Resonance of Double-Gimbal Control Moment Gyro With High-Speed Magnetically Suspended Rotor

Online tuning of fuzzy PID controllers via rule weighing based on normalized acceleration

Research highlights? Electro-hydraulic actuators (EHAs) are especially paid attention in heavy industry. ? An online smart tuning fuzzy PID (OSTFPID) controller is designed for press machines. ? Here, the fuzzy PID structure is optimized by a robust extended Kalman filter. ? An electro-hydraulic test machine (EHTM) is setup to investigate pressing forces. ? Experiments are carried out to evaluate the effectiveness control method. Electro-hydraulic actuators (EHAs) have a wide range of applications where force or position control with high accuracy is exceedingly necessary. Among them, press machines applied hybrid EHAs are more and more used in the heavy industry. This paper presents an online smart tuning fuzzy PID (OSTFPID) approach based on a robust extended Kalman filter (REKF) for the development of high force control precision in the press machines. Here, the main control unit employs the fuzzy PID structure of which membership function (MF) optimization is considered as a system identification problem. A smart selection procedure (SSP) is implemented to pick out only fuzzy input and output MFs activated at each running step, and then the REKF algorithm is used to tune the active MFs automatically during the operation process to minimize the control error. Consequently, the active MFs are trained about their shapes and positions to adapt to the working conditions. As the result, the control performance is significantly improved, while the optimizing time and number of the controller calculations are remarkably reduced. In order to verify the ability of the proposed controller applied to the press machines using EHAs, a test press bench system called electro-hydraulic test machine (EHTM) is also suggested and setup to use in this study. Real-time experiments on the EHTM are carried out to evaluate the control method in a large variation of working environments. Considerable improvement in the performance generated by the designed controller is compared with the traditional PID and fuzzy PID controllers.

Force control for press machines using an online smart tuning fuzzy PID based on a robust extended Kalman filter

Rotor imbalance causes undesirable synchronous vibrations of displacement, force and torque. An active vibration control (AVC) method achieving the minimum vibration force and torque within a desired vibration displacement is presented in an active magnetic bearing (AMB) system. First, the dynamics of the AMB system with static imbalance and dynamic imbalance are introduced, and the dimensional displacement relationships of the rotation, geometric and inertial axes of the rotor are described. Demands of the AVC are analyzed, and the results indicate that the rotation axis has to be controlled to move along the center line and the inclination direction of the geometric axis and the inertial axis, respectively. Then the synchronous vibration displacement is identified with a general notch filter, and a feedforward controller is designed to control the rotation axis by providing a synchronous control current. A gain phase modifier (GPM) is proposed to achieve a precise synchronous control current and to comp...

Active vibration control of rotor imbalance in active magnetic bearing systems

Interval type-2 fuzzy inverse controller design in nonlinear IMC structure

This paper presents a design for a fuzzy gain tuning mechanism dealing with the problem of unbalanced vibration problem in an active magnetic bearing (AMB) system. For the purpose of enhancing the performance of the AMB system, we replace the conventional proportional-integral-derivative (PID) controller with a self-tuning fuzzy PID-type controller (FPIDC). The shaft displacement and the unbalanced forces of the rotor are evaluated by model-based observation. If there are model uncertainties in the rotor system or nonlinearities in the magnetic bearing system, this observer may not work well at any operating speed. A fuzzy gain tuner is added to adjust the actuating signal of the self-tuning FPIDC in order to overcome the disturbances and suppress the unbalancing vibration. The experimental results show that the proposed scheme allows for a remarkable improvement in reducing vibration in an unbalanced AMB system as well as demonstrate an efficient reduction in the shaft displacement of the rotor.

A self-tuning fuzzy PID-type controller design for unbalance compensation in an active magnetic bearing

This paper deals with the unbalanced vibration problem of a stabilized active magnetic bearing (AMB) system. First, a model-based integral-type observer is proposed to evaluate the shaft displacement and the unbalancing forces of the rotor of an AMB system controlled by a proportional-integral-derivative (PID) controller. A fuzzy gain tuning mechanism is added to adjust the output of the PID controller in order to overcome the disturbances and suppress the unbalancing vibration. We have shown via simulation that the addition of the integral-type force observer improves the rotating accuracy in the device operating range. The experimental results demonstrate an efficient reduction of the shaft displacement of the rotor. Thus, the proposed scheme allows for a remarkable improvement in the unbalanced vibration of an AMB system over conventional PID controls without fuzzy gain tuning mechanism.

Mong-Tao Tsai

Papers

A self-tuning fuzzy PID-type controller design for unbalance compensation in an active magnetic bearing

Design of model-based unbalance compensator with fuzzy gain tuning mechanism for an active magnetic bearing system