Design of a Hydraulic Actuator for Active Control of Rotating Machinery

1993 ◽  
Vol 115 (2) ◽  
pp. 336-340 ◽  
Author(s):  
M. Rashidi ◽  
E. Dirusso
Keyword(s):  
Active Control ◽  
Optimum Design ◽  
Elastic Plate ◽  
Electromagnetic Force ◽  
Characteristic Number ◽  
Rotating Machinery ◽  
Rotor System ◽  
Thin Elastic Plate ◽  
Hydraulic Actuator ◽  
Nominal Pressure

A hydraulic actuator was designed and is described herein. This actuator consists of: a pump, which generates the nominal pressure, a hydraulic servovalve, and a thin elastic plate, which transduces the generated pressure variations into forces acting on a mass, which simulates the bearing of a rotor system. An actuator characteristic number is defined to provide a base for an optimum design of force actuators with combined weight, frequency, and force considerations. This characteristic number may also be used to compare hydraulic and electromagnetic force actuators. In tests this actuator generated 182.3 N force at a frequency of 100. Hz. and a displacement amplitude of 5.8×10−5 m.

scholarly journals Design of a Hydraulic Actuator for Active Control of Rotating Machinery

1991 ◽  
Author(s):  
Majid Rashidi ◽  
Eliseo Dirusso
Keyword(s):  
Active Control ◽  
Optimum Design ◽  
Elastic Plate ◽  
Electromagnetic Force ◽  
Characteristic Number ◽  
Rotating Machinery ◽  
Thin Elastic Plate ◽  
Hydraulic Actuator ◽  
Nominal Pressure ◽  
Hydraulic Servo

A Hydraulic actuator was designed and is described herein. This actuator consists of: a pump which generates the nominal pressure, a hydraulic servo-valve, and a thin elastic plate which transduces the generated pressure variations into forces acting on a mass which simulates the bearing of a rotor system. An actuator characteristic number is defined to provide a base for an optimum design of force actuators with combined weight, frequency, and force considerations. This characteristic number may also be used to compare hydraulic and electromagnetic force actuators. In tests this actuator generated 182.3 Newton force at a frequency of 100. Hz. and a displacement amplitude of 5.8×10−5 meter.

Probabilistic Model-Based Fault Diagnosis of the Rotor System

2007 ◽  
Author(s):  
Jiye Shao ◽  
Rixin Wang ◽  
Jingbo Gao ◽  
Minqiang Xu
Keyword(s):  
Fault Diagnosis ◽  
Bayesian Network ◽  
Network Model ◽  
Rotating Machinery ◽  
Rotor System ◽  
Bayesian Network Model ◽  
Diagnosis System ◽  
Model Based ◽  
Core Components ◽  
Fault Diagnosis System

The rotor is one of the most core components of the rotating machinery and its working states directly influence the working states of the whole rotating machinery. There exists much uncertainty in the field of fault diagnosis in the rotor system. This paper analyses the familiar faults of the rotor system and the corresponding faulty symptoms, then establishes the rotor’s Bayesian network model based on above information. A fault diagnosis system based on the Bayesian network model is developed. Using this model, the conditional probability of the fault happening is computed when the observation of the rotor is presented. Thus, the fault reason can be determined by these probabilities. The diagnosis system developed is used to diagnose the actual three faults of the rotor of the rotating machinery and the results prove the efficiency of the method proposed.

PI Control of HSFDs for Active Control of Rotor-Bearing Systems

1997 ◽  
Vol 119 (3) ◽  
pp. 658-667 ◽  
Author(s):  
J. P. Hathout ◽  
A. El-Shafei
Keyword(s):  
Vibration Control ◽  
Active Control ◽  
Closed Loop ◽  
Rotating Machinery ◽  
Loop System ◽  
Pi Control ◽  
Closed Loop System ◽  
Transient Vibration ◽  
Critical Speeds ◽  
Rotor Bearing

This paper describes the proportional integral (PI) control of hybrid squeeze film dampers (HSFDS) for active control of rotor vibrations. Recently it was shown that the automatically controlled HSFD based on feedback of rotor speed can be a very efficient device for active control of rotor vibration when passing through critical speeds. Although considerable effort has been put into the study of steady-state vibration control, there are few methods in the literature applicable to transient vibration control of rotor-bearing systems. Rotating machinery may experience dangerously high dynamic loading due to the sudden mass unbalance that could be associated with blade loss. Transient run-up and coast down through critical speeds when starting up or shutting down rotating machinery induces excessive bearing loads at criticals. In this paper, PI control is proposed as a regulator for the HSFD system to attenuate transient vibration for both sudden unbalance and transient runup through critical speeds. A complete mathematical model of this closed-loop system is simulated on a digital computer. Results show an overall enhanced behavior for the closed-loop rotor system. Gain scheduling of both the integral gain and the reference input is incorporated into the closed-loop system with the PI regulator and results in an enhanced behavior of the controlled system.

scholarly journals Active control of structural intensity in an elastic plate

1995 ◽  
Vol 97 (5) ◽  
pp. 3331-3331 ◽  
Author(s):  
S. I. Hayek ◽  
M.‐Y. Nam ◽  
S. Sommerfeldt
Keyword(s):  
Active Control ◽  
Elastic Plate ◽  
Structural Intensity

Internal Rotor Friction Induced Instability in High-Speed Rotating Machinery

1993 ◽  
Author(s):  
James F. Walton ◽  
Michael R. Martin
Keyword(s):  
Internal Friction ◽  
Natural Frequency ◽  
High Speed ◽  
Critical Speed ◽  
Rotating Machinery ◽  
Rotor System ◽  
Analytical Models ◽  
Interference Fit ◽  
Internal Rotor

Abstract Results of a program to investigate internal rotor friction destabilizing effects are presented. Internal-friction-producing joints were shown to excite the rotor system first natural frequency, when operating either below or above the first critical speed. The analytical models used to predict the subsynchronous instability were also confirmed. The axial spline joint demonstrated the most severe subsynchronous instability. The interference fit joint also caused subsynchronous vibrations at the first natural frequency but these were bounded and generally smaller than the synchronous vibrations. Comparison of data from the two test joints showed that supersynchronous vibration amplitudes at the first natural frequency were generally larger for the interference fit joint than for the axial spline joint. The effects of changes in imbalance levels and side loads were not distinguishable during testing because amplitude-limiting bumpers were required to restrict orbits.

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