New method to eliminate the cross-coupling effect in gravity measurements at sea

1967 ◽  
Vol 72 (8) ◽  
pp. 2199-2207 ◽  
Author(s):  
Hans-Dieter Jacoby ◽  
Reinhard Schulze
Keyword(s):  
Coupling Effect ◽  
Cross Coupling ◽  
New Method ◽  
Gravity Measurements ◽  
The Cross

Modeling of Cross-Coupling Responses on Hingeless Helicopters via Gyroscopic Effect

2012 ◽  
Vol 7 (2) ◽  
Author(s):  
Tak Kit Lau ◽  
Yun-hui Liu
Keyword(s):  
Angular Momentum ◽  
Pitch Angle ◽  
Cross Coupling ◽  
Modeling Method ◽  
New Method ◽  
Phase Lag ◽  
Gyroscopic Effect ◽  
Actuation Mechanism ◽  
The Cross

The perplexing cross-coupled responses between the control axes on hingeless helicopters have puzzled researchers for years. Unlike previous studies, which introduced a physically meaningless phase-lag to account for the cross-couplings, this paper proposes a new method to relate both on-axis and off-axis responses by the gyroscopic moments through the actuation mechanism of hingeless helicopters. This new method allows investigators to directly and analytically quantify the debatable cross-coupling due to the complex actuation of the rotor. This method is based on the fact that when the angular momentum of the spinning rotor is disturbed by an incremental lift along the main blades due to the varying cyclic pitch angle controlled by the servo mechanisms, off-axis moments are induced to counteract the changes in angular momentum according to the principles of the gyroscope, and hence these gyroscopic moments directly exhibit on-axis responses. This new method yields a parametric framework for examining the previously unexplained cross-coupled responses of hingeless helicopters and demonstrates that, in addition to aerodynamics, intricate dynamic nonlinearities also occur due to non-intuitive actuation mechanisms on the rotor of hingeless helicopters. Finally, simulations and experiments were performed to validate the proposed modeling method.

Cross-Feedback Stabilization of the Digitally Controlled Magnetic Bearing

1992 ◽  
Vol 114 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Y. Okada ◽  
B. Nagai ◽  
T. Shimane
Keyword(s):  
Pid Control ◽  
High Speed ◽  
Coupling Effect ◽  
Cross Coupling ◽  
Magnetic Bearing ◽  
Feedback Stabilization ◽  
Time Interval ◽  
Rotating Disc ◽  
Digitally Controlled ◽  
The Cross

A method of stabilizing a high speed rotor supported by magnetic bearings is presented. The magnetic bearing is controlled by a digital controller with rotationally synchronized interruption. The main problem with the rotating disc is the cross-coupling effect caused by the gyroscopic or inductive forces which sometimes make the high speed rotor unstable. Standard PID control is carried out with constant time interval interruption, while the rotational interrupt subroutine performs the cross-coupling feedback. The cross-feedback in the x-y directions well compensates for the undesirable coupling effect. This scheme is applied to a four-mass, two-bearing rotor system and its capability is tested.

Theoretical Investigation on Cross-Coupling Effect of Two-Dimensional Compound Pendulum Tiltmeter

2018 ◽  
Vol 07 (02n03) ◽  
pp. 1850007
Author(s):  
Lihua Wu ◽  
Yu Huang
Keyword(s):  
Dynamic Response ◽  
Vibration Isolation ◽  
Coupling Effect ◽  
Low Frequency ◽  
Cross Coupling ◽  
Coupling Factor ◽  
Two Dimensional ◽  
Coupling Coefficients ◽  
Coupling Effects ◽  
The Cross

The active vibration isolation of low-frequency tilt is important for precise scientific measurement. However, the cross-coupling effects in tilt sensitive probes introduce negative effects on the performance of active isolation devices. In this paper, we show the structure and basic principle of compound pendulum (CP)-type tiltmeter, and analyze the dynamic response of the CP to the two-dimensional tilt vibrations. Besides, we deduce theoretically the mathematical model of the capacitive sensing of the displacements of the CP. Finally, we evaluate numerically the cross-coupling effects of a tilt sensitive probe including the cross-couplings of dynamic response and the different capacitance variations in two orthogonal degrees of freedoms. The maximum of the mechanical dynamic coupling factor is less than −60[Formula: see text]dB. The total cross-coupling coefficients including the different capacitance variations of the probe are both less than [Formula: see text]. Therefore, the cross-coupling effects don’t have to be considered for this kind of two-dimensional tilt sensitive probe.

scholarly journals Time-Sharing Control Strategy for Multiple-Receiver Wireless Power Transfer Systems

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 599 ◽  
Author(s):  
Weikun Cai ◽  
Dianguang Ma ◽  
Xiaoyang Lai ◽  
Khurram Hashmi ◽  
Houjun Tang ◽  
...  
Keyword(s):  
Control Strategy ◽  
Output Voltage ◽  
High Efficiency ◽  
Coupling Effect ◽  
Cross Coupling ◽  
Time Sharing ◽  
Voltage Control Strategy ◽  
Bridge Rectifier ◽  
The Cross ◽  
Target Output

The cross-coupling effect between the induction coils of a multiple-receiver wireless power transfer (MRWPT) system severely weakens its overall performance. In this paper, a time-sharing control strategy for MRWPT systems is proposed to reduce the cross-coupling between receiver coils. An active-bridge rectifier is introduced to the receivers to replace the uncontrollable rectifier to achieve synchronization of the time-sharing control. The synchronization signal generated by an active-bridge rectifier can be directly used to realize the synchronization of time-sharing control and hence saved the traditional zero-crossing point detection circuits for time-sharing circuits. Moreover, the proposed time-sharing system has the advantages of both operating under a resistance-matching condition and providing target output voltage for each receiver. Furthermore, a voltage control strategy was developed to provide both high efficiency and a target output voltage for each receiver. Finally, the simulation and experimental results show that the time-sharing MRWPT system reduced the cross-coupling effect between the receiver coils, and the voltage control strategy provided both a high efficiency and a target output voltage for each receiver.

Alternative soft fault model of the cross-coupling effect correlated at hydroelectric power energy system

2014 ◽  
Vol 58 ◽  
pp. 274-280
Author(s):  
G. Mino-Aguilar ◽  
G.A. Muñoz-Hernández ◽  
J.F. Guerrero-Castellanos ◽  
E. Molina-Flores ◽  
A. Díaz-Sánchez ◽  
...  
Keyword(s):  
Coupling Effect ◽  
Cross Coupling ◽  
Energy System ◽  
Fault Model ◽  
Hydroelectric Power ◽  
Soft Fault ◽  
The Cross
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