Vibration and Shape Control in Opto-mechanical Systems Using Distributed Fiber-optic Bragg Grating Sensors

High-precision opto-mechanical systems are characterized by significant interactions between structural dynamics and optics. Novel sensing techniques for the vibration and shape control of such structures are investigated. Owing to the number of necessary sensors and the required precision, fiber-optic Bragg grating (FBG) sensors could be an attractive option for this task. They allow the simultaneous measurement of strain at many locations in a structure. Many FBG sensor systems provide high precision, but their delay time and maximum acquisition frequency makes them difficult to use for vibration control purposes. Therefore, a novel multi-channel FBG sensor system was developed using a position sensitive detector for the wavelength interrogation which has much less delay time than a charge coupled device-based system and a theoretical maximum bandwidth of over 300 kHz. This system was tested for high-precision static strain measurements for shape control applications at low frequencies in an experimental test rig (< 0.3 μm/m) as well as for high-frequency strain measurements of more than 10 kHz. Its application potential for shape and vibration control application was demonstrated experimentally as well as its applicability to modal analysis. This could be an interesting alternative to the use of piezo-strain sensors in structural control applications where high frequencies are needed, as well as an alternative for shape control where high-resolution strain measurements are desirable.

[1]  André Preumont,et al.  PIEZOELECTRIC ARRAY SENSING OF VOLUME DISPLACEMENT: A HARDWARE DEMONSTRATION , 2001 .

[2]  N. Djilali,et al.  In-fibre Bragg grating sensors for distributed temperature measurement in a polymer electrolyte membrane fuel cell , 2009 .

[3]  Leonard Meirovitch,et al.  Dynamics And Control Of Structures , 1990 .

[4]  W. Gawronski.  Dynamics and control of structures : a modal approach , 1998 .

[5]  M. Balas,et al.  Feedback control of flexible systems , 1978 .

[6]  R. Measures.  Structural Monitoring with Fibre Optic Technology , 2001 .

[7]  Steven Dubowsky,et al.  DISPLACEMENTS IN A VIBRATING BODY BY STRAIN GAUGE MEASUREMENTS , 2000 .

[8]  Eric Udd,et al.  Fiber optic smart structures , 1993, Optics East.

[9]  Byoungho Lee,et al.  Review of the present status of optical fiber sensors , 2003 .

[10]  Jae-Hung Han,et al.  Dynamic shape estimation by modal approach using fiber Bragg grating strain sensors , 2007, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[11]  Kenneth B. Lazarus,et al.  Fundamental mechanisms of aeroelastic control with control surface and strain actuation , 1991 .

[12]  Wodek Gawronski,et al.  Dynamics and Control of Structures , 1998 .

[13]  K. Hill,et al.  Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication , 1978 .

[14]  K. Hill,et al.  Fiber Bragg grating technology fundamentals and overview , 1997 .

[15]  P. Bely.  The Design and Construction of Large Optical Telescopes , 2010 .

[16]  Uwe Stöbener,et al.  Modal Vibration Control for PVDF Coated Plates , 2000 .

[17]  Raphael T. Haftka,et al.  An analytical investigation of shape control of large space structures by applied temperatures , 1985 .

[18]  Jae-Hung Han,et al.  Estimation of dynamic structural displacements using fiber Bragg grating strain sensors , 2007 .

[19]  G. A. Cranch,et al.  Efficient large-scale multiplexing of fiber Bragg grating and fiber Fabry-Perot sensors for structural health monitoring applications , 2006, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[20]  M. Balas.  Direct Velocity Feedback Control of Large Space Structures , 1979 .

[21]  Alexander W. Koch,et al.  Fiber optic Bragg grating sensors for high-precision structural deformation control in optical systems , 2006, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[22]  E. Haugse,et al.  Using Modal Test Results to Develop Strain to Displacement Transformations , 1995 .