A simple feed-forward control algorithm for fast dynamic gain profile control in a multiwavelength forward-pumped Raman fiber amplifier

2006 ◽  
Vol 18 (9) ◽  
pp. 1004-1006 ◽  
Author(s):  
Xiang Zhou ◽  
M. Feuer ◽  
M. Birk
Author(s):  
Sudhir Kaul

This paper demonstrates the use of two feed-forward control algorithms in order to mitigate crack propagation in a simply supported beam with a pre-existing crack. The main objective of the control algorithms is to minimize or reduce transverse deflection at the crack location so as to contain the damage resulting from the pre-existing crack and, thereby, reduce the rate of crack propagation. A point-load sinusoidal excitation, from a known disturbance, is used as the input load acting on the beam. Two control algorithms are used — the first control algorithm computes a control force to eliminate transverse displacement at the crack location resulting from the excitation force, and the second control algorithm minimizes the mean square transverse displacement over a section of the beam that contains the crack. Both the control algorithms are a-causal and assume that the excitation input is completely known a-priori. Simulation results for a simply supported beam are presented and discussed in detail. It is observed that the rate of crack propagation can be significantly reduced by implementing the proposed feed-forward control algorithms, increasing the useful life of the damaged beam. Also, it is found that the transverse displacement over a significant length of the beam can be substantially reduced when the beam response is dominated by a specific mode.


2005 ◽  
Author(s):  
Ji-Ping Ning ◽  
Qun Han ◽  
Zhi-Qiang Chen ◽  
Xiao-Guang Li ◽  
Jia-Qiang Li

Author(s):  
Andreas Wildschek ◽  
Rudolf Maier ◽  
Falk Hoffmann ◽  
Matthieu Jeanneau ◽  
Horst Baier

2018 ◽  
Vol 226 ◽  
pp. 04014
Author(s):  
Valery V. Fomin

In the heating of buildings during positive dynamics of weather conditions a problem is encountered of air temperature rise in the rooms of the building. Solution of the problem given the buildings are equipped with heating system controllers is a practical task using update algorithms in the operation of controllers. The proposed method offers an option of a heating system control algorithm to attain stable temperatures in the rooms of the building.


2013 ◽  
Vol 336-338 ◽  
pp. 978-981
Author(s):  
Yue Rong Zhao ◽  
Li Ping Shi ◽  
Yong Li Bi ◽  
Li Jing Wang

Piezoelectric actuator has the characteristics of high displacement resolution, fast dynamic response, miniature size and etc. But its inherent hysteresis nonlinear affects its positioning accuracy. This paper analysis the hysteresis nonlinear characteristics of piezoelectric actuator, verifies the effect of hysteresis nonlinear on piezoelectric actuator, and compensate the hysteresis nonlinear characteristics by using the integrated control algorithm of feed-forward control and PI control, which can improve the control precision of the piezoelectric actuator.


Author(s):  
Jiaming Wu ◽  
Dongjun Chen ◽  
Ying Xu ◽  
Yuqing Chen ◽  
Lihua Lu

A three-dimensional hydrodynamic and control model to simulate tethered underwater robot system is proposed. The fluid motion around the moving robot main body with running control ducted propellers is governed by Navier-Stokes equations, and multiple sliding mesh technique is applied to solve the governing equations. The governing equation of umbilical cable connected to the robot is based on the Ablow and Schechter method. The six-degrees-of-freedom equations of motion for underwater vehicle simulations proposed by Gertler and Hargen are adopted to estimate the hydrodynamic performance of the underwater robot. In the model, the feed-forward control algorithm is applied to adjust the length of the umbilical cable according to the robot trajectory control target, the incremental PID control algorithm is adopt to regulate the rotating speeds of the ducted propellers producing appropriate thrusts for the robot control. With the proposed hydrodynamic and control model, hydrodynamic behaviors of the robot under definite trajectory control manipulations are observed numerically. The numerical results of robot trajectory control simulations indicate that the feed-forward control algorithm for adjusting the length of the umbilical cable, and the incremental PID control algorithm for regulating the rotating speeds of the propellers are feasible and effective, the adjusting the length of the umbilical cable with feed-forward control technique is largely responsible for the vertical trajectory control to the robot, while regulating the rotating speeds of the propellers by the PID control algorithm play a leading role in the horizontal trajectory manipulation, the deviation between the designated trajectory and the control one at each time step is acceptable.


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