Session: 23-05 Special Bearings

Paper Number: 153103

Stability Analysis of Flexible Rotor Supported by Active Hybrid Bearing With Fuzzy Logic–Based Control 

The classic film hydrodynamic bearing is a passive device, and its design does not consider the adaptive capacity to change with operation conditions. The film journal bearing coupling with servo valve, controller, and sensor, called active controllable hybrid journal bearing(AHB), can accept controllable orifice flow to produce active force for reducing the rotor vibration and adapt to different operation demands.

The AHB is modeled as a couple of four parts: film, orifice flow, servo valve, and controller. The orifice flow is modeled as the series of a servo valve, capillary restrictor, and gap restrictor, considering the throttling effect of the servo valve, orifice tube, and film gap. The spool motion of the servo valve is modeled as a third-order transfer function and controlled by the fuzzy PID controller. The feedback signal is the center displacement of the journal. The governing equation of film pressure is a modified Reynolds equation containing the orifice flow, which is linearized by the Newton-Raphson method and calculated by the finite element method to get the static characteristic. The result indicates that the proportional coefficient significantly affects the bearing load capacity. When the dimensionless load is between 0 and 0.6, the max increment of the minimum film thickness can be 10%.

The time domain response of the rotor with the transient oil film force is calculated in passive and active control operations. Compared with passive operation, the amplitude at the bearing can be reduced by 23% in active control operation. The dynamic coefficient of AHB is calculated using the orbit analysis method. The perturbation method is usually practical for analyzing the bearing dynamic characteristic but is unreliable in large eccentricity tracks. In addition, the orbit analysis method can provide more reliable results for dynamic characteristics when bearing models are challenging to linearize. The influence of operating parameters on the dynamic characteristics of the AHB is studied. The result indicates that the stiffness and damping of the bearing can be increased by up to 20% under active control operation by selecting an appropriate range of control parameters.

In conclusion, AHB has better static and dynamic characteristics than hydrodynamic journal bearing. Besides, The rotor supported by active controllable hybrid bearings has better stability than passive operation.

Presenting Author: Wenjie Gong Harbin Institute of Technology

Presenting Author Biography: Male, born in 1998, Ph.D. candidate. His main research interests are vibration control, dynamic and static hybrid bearings and active control

Authors:

Wenjie Gong Harbin Institute of Technology
Guanghui Zhang Harbin Institute of Technology
Zehao Lin Harbin Institute of Technology
Kefan Xu Harbin Institute of Technology
Jiazhen Han Harbin Institute of Technology
Yanzhong Huang Harbin Institute of Technology
Zhongwen Huang Nanjing Engineering Institute of Aircraft Systems, Aviation Industry Corporation of China