scholarly journals Performance of an Electromagnetic Bearing for the Vibration Control of a Supercritical Shaft

1987 ◽  
Vol 201 (3) ◽  
pp. 201-212 ◽  
Author(s):  
C D Bradfield ◽  
J B Roberts ◽  
R Karunendiran
Keyword(s):  
Vibration Control ◽  
Control Algorithm ◽  
Control Strategies ◽  
Single Point ◽  
Test Rig ◽  
Rotating Shaft ◽  
Linear Spring ◽  
Measured Displacement ◽  
Control Forces ◽  
Electromagnetic Bearing

The flexural vibrations of a rotating shaft, running through one or more critical speeds, can be reduced to an acceptably low level by applying suitable control forces at an intermediate span position. If electromagnets are used to produce the control forces then it is possible to implement a wide variety of control strategies. A test rig is described which includes a microprocessor-based controller, in which such strategies can be realized in terms of software-based algorithms. The electromagnet configuration and the method of stabilizing the electromagnet force–gap characteristic are discussed. The bounds on the performance of the system are defined. A simple control algorithm is outlined, where the control forces are proportional to the measured displacement and velocity at a single point on the shaft span; in this case the electromagnet behaves in a similar manner to that of a parallel combination of a linear spring and damper. Experimental and predicted performances of the system are compared, for this type of control, where various programmable rates of damping are applied.

A Programmable Electromagnetic Bearing for Vibration Control of a Flexible Shaft

1991 ◽  
Vol 113 (2) ◽  
pp. 160-166 ◽  
Author(s):  
C. D. Bradfield ◽  
J. B. Roberts ◽  
S. Karunendiran
Keyword(s):  
Vibration Control ◽  
Control Strategy ◽  
Stiffness Coefficient ◽  
Test Rig ◽  
Microprocessor Control ◽  
Transverse Vibrations ◽  
Flexible Rotors ◽  
Theoretical Predictions ◽  
Control Forces ◽  
Electromagnetic Bearing

The transverse vibrations of flexible rotors can be reduced to safe levels by radial control forces at an intermediate span position, applied by a suitable actuator. One versatile control strategy applies forces proportional to displacement and velocity, with coefficients dependent on the rotational speed. This control can be realized with an electromagnetic bearing under microprocessor control. Suitable microprocessor software is described, to implement the required real-time computation of the control forces. Experimental results obtained from a test rig are compared with theoretical predictions. There are advantages in allowing the stiffness coefficient to become negative, provided that positive damping is simultaneously applied.

scholarly journals Experimental Analysis of a Novel Double Damper System with Semi-Active Control

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1518
Author(s):  
Anish Gorantiwar ◽  
Rajvardhan Nalawade ◽  
Arash Nouri ◽  
Saied Taheri
Keyword(s):  
Control Algorithm ◽  
Performance Metrics ◽  
Control Strategies ◽  
Normal Load ◽  
Data Acquisition System ◽  
Test Rig ◽  
Strong Basis ◽  
Acceleration Data ◽  
Separate Control ◽  
Active Damper

An experimental study was conducted to compare the performance of an in-house built novel double semi-active damper against a conventional semi-active single damper. Different performance metrics were analyzed, and the performance of the two dampers was evaluated based on these metrics. A Hybrid Skyhook–Groundhook control algorithm was developed and implemented on the variable orifice double damper. The semi-active single damper is governed via two separate control strategies, namely—Skyhook and Groundhook control, respectively. The effectiveness of each algorithm is better understood by adding a normal load on top of the Shock Dyno, thus modifying it to act as a quarter car test rig. The sprung and unsprung acceleration data are collected via the accelerometers mounted on the Shock Dyno through a Data Acquisition System. The results obtained from this experiment provide a strong basis that the semi-active double damper performs better in terms of the comfort cost than that of the commercial semi-active single dampers.

Reducing RMS on Wheel Load in ABS-Braking Situations by Control of Semi-Active Suspension

2006 ◽  
Author(s):  
Tobias Niemz ◽  
Hermann Winner
Keyword(s):  
Control Algorithm ◽  
Control Strategies ◽  
Simulation Models ◽  
Time Behavior ◽  
Test Rig ◽  
Passenger Cars ◽  
Wheel Load ◽  
Minimax Control ◽  
Change Effect ◽  
Braking Distance

In the presented research project the authors’ goal is to determine the potential of reduction of braking distance by automatic control of active dampers in passenger cars. Control strategies are being developed and tested in simulation models to be validated afterwards in test stand trials and test drives. In the presented paper the model assumptions regarding the vibration behavior of the vertical dynamics of the testing vehicle were checked. The assumptions regarding the influence on the wheel load of adaptive dampers could be verified and information about the time behavior and about the strength of the damper change effect could be gained. A control algorithm for the active dampers was developed and implemented in a testing vehicle. The control algorithm, which is called MiniMax control, makes it possible to reduce the RMS on dynamic wheel load in non-braking situations significantly. This could be shown in test rig trials as well as in test drives with defined obstacles. In full braking test drives the chosen controller is able to reduce the RMS on wheel load at initial velocities up to 70 km/h.

Closed-Loop Vibration Control of Flexible Rotors—An Experimental Study

1993 ◽  
Vol 207 (1) ◽  
pp. 1-17 ◽  
Author(s):  
C R Burrows ◽  
P S Keogh ◽  
R Tasaltin
Keyword(s):  
Experimental Study ◽  
Vibration Control ◽  
State Feedback ◽  
Closed Loop ◽  
Dominant Mode ◽  
Pole Placement ◽  
Magnetic Actuator ◽  
Flexible Rotors ◽  
Measured Displacement ◽  
Control Forces

An experimental study has been made for the synchronous vibration control of a rotor-bearing system using a magnetic actuator to supply the control forces. Both open- and closed-loop strategies were implemented using measured displacement signals from various transducer configurations. Model reduction based on dominant mode methods was used to aid the design of the closed-loop strategies. These were based on pole placement techniques. It was shown that state feedback, without co-location of sensors and actuator, can be used to suppress critical speed responses without encountering spillover problems. The robustness of the strategies was also assessed by deleting selected feedback paths.

scholarly journals Overlapping Decentralized Control Strategies of Building Structures’ Vibration with Time Delay Based on H∞ Control Algorithms under Seismic Excitation

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiaofang Kang ◽  
Jian Wu ◽  
Yewei Zhang ◽  
Guoliang Liu ◽  
Suhui Zhang ◽  
...  
Keyword(s):  
Control System ◽  
Time Delay ◽  
Vibration Control ◽  
Decentralized Control ◽  
Control Strategy ◽  
Control Algorithm ◽  
Control Method ◽  
Control Strategies ◽  
Linear Matrix ◽  
Feedback Gain

A decentralized control strategy can effectively solve the control problem of the large-scale time delayed structures. In this paper, combining the overlapping decentralized control method, linear matrix inequality (LMI) method, and H∞ control algorithm, overlapping decentralized H∞ control approach of the time delayed structures has been established. The feedback gain matrixes of all subsystems are obtained by this method based on genetic algorithm optimization tools and the specific goal of optimization control. The whole vibration control system of the time delayed structures is divided into a series of overlapping subsystems by overlapping decentralized control strategy. The feedback gain matrixes of each subsystem can be obtained by using H∞ control algorithm to calculate each subsystem. The vibration control of a twenty layers’ antiseismic steel structure Benchmark model was analyzed with the numerical method. The results show that the proposed method can be applied to control system with time delay. The overlapping decentralized control strategies acquire the similar control effects with that of the centralized control strategy. Moreover, the flexibility of the controller design has been enhanced by using overlapping decentralized control strategies.

Vibration control of multi-mode rotor-bearing systems

1983 ◽  
Vol 386 (1790) ◽  
pp. 77-94 ◽  
Keyword(s):  
Vibration Control ◽  
Least Squares Method ◽  
Control Strategies ◽  
Open Loop ◽  
External Control ◽  
Wide Range ◽  
Rotor Bearing ◽  
Optimum Response ◽  
Control Forces ◽  
Adaptive Vibration Control

This paper presents a computationally fast and efficient least-squares method to minimize the vibration of any general rotor-bearing system by the application of external control forces. The D-optimality concept is used to optimize the force locations. The proposed method provides a wide range of statistical information, and the sensitivity of the optimum response to changes in the control forces. Magnetic bearings can be applied to implement the open-loop adaptive vibration control strategies outlined in the paper. These components can also be used to inject a multi-frequency test signal as required for identi­fication studies.

scholarly journals A Variable Parameter Ambient Vibration Control Method Based on Quasi-Zero Stiffness in Robotic Drilling Systems

Machines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 67
Author(s):  
Laixi Zhang ◽  
Chenming Zhao ◽  
Feng Qian ◽  
Jaspreet Singh Dhupia ◽  
Mingliang Wu
Keyword(s):  
Vibration Control ◽  
Vibration Isolation ◽  
Control Method ◽  
Control Strategies ◽  
Equations Of Motion ◽  
Variable Parameter ◽  
Harmonic Balance Method ◽  
Variable Stiffness ◽  
Ambient Vibration ◽  
Robotic Drilling

Vibrations in the aircraft assembly building will affect the precision of the robotic drilling system. A variable stiffness and damping semiactive vibration control mechanism with quasi-zero stiffness characteristics is developed. The quasi-zero stiffness of the mechanism is realized by the parallel connection of four vertically arranged bearing springs and two symmetrical horizontally arranged negative stiffness elements. Firstly, the quasi-zero stiffness parameters of the mechanism at the static equilibrium position are obtained through analysis. Secondly, the harmonic balance method is used to deal with the differential equations of motion. The effects of every parameter on the displacement transmissibility are analyzed, and the variable parameter control strategies are proposed. Finally, the system responses of the passive and semiactive vibration isolation mechanisms to the segmental variable frequency excitations are compared through virtual prototype experiments. The results show that the frequency range of vibration isolation is widened, and the stability of the vibration control system is effectively improved without resonance through the semiactive vibration control method. It is of innovative significance for ambient vibration control in robotic drilling systems.

Servo Control Strategies for Vibration-Control in Robotic Wire EDM Machining

2021 ◽  
Author(s):  
Sergio Tadeu Almeida ◽  
John P. T. Mo ◽  
Cees Bil ◽  
Songlin Ding ◽  
Xiangzhi Wang
Keyword(s):  
Vibration Control ◽  
Control Strategies ◽  
Servo Control ◽  
Wire Edm

Development of Dedicated Controller for HVAC

2012 ◽  
Vol 430-432 ◽  
pp. 1472-1476
Author(s):  
Jin Ming Yang ◽  
Yi Lin
Keyword(s):  
Fuzzy Control ◽  
Control Algorithm ◽  
Control Strategies ◽  
Control Software ◽  
Interface Circuits ◽  
Pid Algorithm ◽  
Hardware Interface ◽  
Hvac Control ◽  
Fuzzy Control Algorithm

This article describes the development of a dedicated controller for HVAC control, and introduces the hardware interface circuits about some main chip on controller. In addition, the article also explains composition and principle about control software applied to the controller, further more points out that the fuzzy control algorithm is more reasonable than the PID algorithm for most HVAC control and dedicated control strategies play an important role for HVAC control.

scholarly journals Vibration Control of Buildings Using Magnetorheological Damper: A New Control Algorithm

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Aly Mousaad Aly
Keyword(s):  
Vibration Control ◽  
Control Algorithm ◽  
Fuzzy Logic Controller ◽  
Mr Damper ◽  
Maximum Energy ◽  
Magnetorheological Damper ◽  
Control Algorithms ◽  
Earthquake Loads ◽  
Building Model ◽  
Lyapunov Controller

This paper presents vibration control of a building model under earthquake loads. A magnetorheological (MR) damper is placed in the building between the first floor and ground for seismic response reduction. A new control algorithm to command the MR damper is proposed. The approach is inspired by a quasi-bang-bang controller; however, the proposed technique gives weights to control commands in a fashion that is similar to a fuzzy logic controller. Several control algorithms including decentralized bang-bang controller, Lyapunov controller, modulated homogeneous friction controller, maximum energy dissipation controller, and clipped-optimal controller are used for comparison. The new controller achieved the best reduction in maximum interstory drifts and maximum absolute accelerations over all the control algorithms presented. This reveals that the proposed controller with the MR damper is promising and may provide the best protection to the building and its contents.

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