Coherent phase-locked single-mode frequency microcombs in the C and L bands without mode-crossing disruptions

2016 ◽  
Author(s):  
H. Liu ◽  
S.-W. Huang ◽  
J. Yang ◽  
A. K. Vinod ◽  
M. Yu ◽  
...  
Keyword(s):  
Single Mode ◽  
Mode Frequency ◽  
Coherent Phase

Single-mode frequency-agile 9-11 um CO2 laser local oscillator

1997 ◽  
Author(s):  
Richard S. Eng ◽  
James F. Cunningham ◽  
Yu-Lin Wang ◽  
Victor H. Hasson
Keyword(s):  
Single Mode ◽  
Local Oscillator ◽  
Mode Frequency ◽  
Frequency Agile

Command-Shaping Control System for Double-Pendulum Gantry Cranes

2011 ◽  
Author(s):  
Ziyad N. Masoud ◽  
Khaled A. Alhazza
Keyword(s):  
Closed Loop ◽  
Single Mode ◽  
Feedback System ◽  
Mode Frequency ◽  
Gantry Crane ◽  
Necessary Condition ◽  
Double Pendulum ◽  
Double Step ◽  
Scaled Model ◽  
Command Shaping

Traditionally, multi-mode command-shaping controllers are tuned to the system frequencies. This work suggests an opposite approach. A frequency-modulation (FM) strategy is developed to tune the system frequencies to match the frequencies eliminated by a single-mode command-shaper. The shaper developed in this work is based on a double-step command-shaping strategy. Using the FM Shaper, a simulated feedback system is used to modulate the closed-loop frequencies of a simulated double-pendulum model to the point where the closed-loop second mode frequency becomes an odd multiple of the closed-loop first mode frequency, which is the necessary condition for a satisfactory performance of a single-mode command-shaper. The double-step command-shaper is based on the closed-loop first mode frequency. The input commands to the plant of the simulated closed-loop system are then used to drive the actual double-pendulum. Performance is validated experimentally on a scaled model of a double-pendulum gantry crane.

Frequency-Modulation Input Shaping Control of Double-Pendulum Overhead Cranes

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Ziyad N. Masoud ◽  
Khaled A. Alhazza
Keyword(s):  
Frequency Modulation ◽  
Closed Loop ◽  
Single Mode ◽  
Mode Frequency ◽  
Input Shaping ◽  
Double Pendulum ◽  
Overhead Crane ◽  
Primary Input ◽  
Shaping Technique ◽  
Input Shaper

Traditionally, multimode input shaping controllers are tuned to systems' frequencies. This work suggests an alternative approach. A frequency-modulation (FM) input shaping technique is developed to tune the resonant frequencies of a system to a set of frequencies that can be eliminated by a single-mode primary input shaper. Most of the current input shaping techniques can be used as primary input shapers for the FM input shaping technique. Virtual feedback is used to modulate the closed-loop frequencies of a simulated double-pendulum model of an overhead crane to the point where the closed-loop second mode frequency becomes an odd-multiple of the closed-loop first mode frequency, which is the necessary condition for a satisfactory performance of most single-mode input shapers. The primary input shaper is based on the first mode frequency of the closed-loop system model. The input commands to the plant of the virtual feedback system are then used to drive the physical double-pendulum. Simulations results, using primary zero-vibration (ZV) and zero-vibration-derivative (ZVD) input shapers, are presented. The performance is validated experimentally on a scaled model of a double-pendulum overhead crane.

A Frequency-Modulation Command-Shaping Strategy for Multi-Mode Systems

2013 ◽  
Author(s):  
Ziyad N. Masoud ◽  
Khaled A. Alhazza
Keyword(s):  
Frequency Modulation ◽  
Closed Loop ◽  
Single Mode ◽  
Mode Frequency ◽  
Loop System ◽  
Loop Model ◽  
Closed Loop System ◽  
Command Shaping ◽  
Scaled Models ◽  
Multi Mode

Single-mode shaped commands can be implemented for oscillations control of multi-mode systems provided that all frequencies of the system are odd-multiples of the shaped command frequency. This criterion is utilized in this work to develop a command shaping strategy for multi-mode systems. A frequency-modulation command shaper is derived based on the use of a single-mode command-shaping technique. The proposed strategy is based on deriving a closed-loop model of a multi-mode system with its modal frequencies modulated so that higher mode frequencies are odd-multiples of the first mode frequency. A single-mode double-step primary command-shaper with a design frequency equal to the first mode frequency of the closed-loop system is then used. The input command to the plant of the closed-loop system is used as shaped commands for the multi-mode system. Numerical simulations are used to demonstrate the performance of the proposed strategy along with experiments on scaled models of a triple, quadruple, and quintuple-pendulums.

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