The ability to monitor shock level is important for missile health monitoring to predict the performance after storage and eliminate potentially damaged units. Shock sensing is also of interest for monitoring the handling conditions of fragile shipments and providing a measure of unit-level quality control not currently available. A MEMS bi-polar single axis latching shock sensor has been developed with the goal of monitoring shock events and with the potential to "wake up" other sensing circuitry after a shock event occurs. An important feature of the sensor is that power is only consumed when a shock event occurs, making it suitable for long-term remote monitoring applications. The shock sensor has been designed, fabricated and characterized. High volume, low unit cost production will be enabled through the use of standard MEMS fabrication technologies such as DRIE and SOI wafer processing.
The Army Aviation and Missile Command (AMCOM), Morgan Research Corporation, and Aegis Research Corporation are developing an SOI-based vibratory-rate z-axis MEMS gyroscope utilizing force-feedback control, and intended for wide dynamic range and harsh environment applications. Rate sensing in small diameter ballistic missile guidance units requires a rate resolution of less than 1 degree(s)/hr over a range of -3000 to +3000 degree(s)/sec, resulting in a dynamic range of 107. In addition, the devices must operate through military specifications on temperature (-55 degree(s)C to +125 degree(s)C) and vibration (1000 g at 5 - 15 kHz). This paper presents modeling, simulation, and fabrication efforts, as well as initial test data, for an SOI-based rate sensor intended for this application. The prototyped gyroscope is a single layer structure consisting of a proof mass placed in a three-fold mode-decoupled symmetric suspension. The device is fabricated in a cost-effective and highly-controllable Silicon-on-Insulator (SOI) process for in-plane inertial devices. The mechanical structure is integrated in a vacuum-sealed hermetic package with a separate CMOS readout ASIC. At the present time, the device has undergone two design iterations, with the most recent just completed.
The U.S. Army Aviation and Missile Command (AMCOM), Research, Development and Engineering Center (AMRDEC), in support of the Unmanned Ground Vehicles/Systems Joint Project Office (UGV/S JPO), has developed, tested and demonstrated the feasibility of use of expendable, thin-buffered, fiber optic cable for tele-operation of unmanned ground systems. Complete Non-Line-of-Sight (NLOS), high bandwidth, expendable, fiber optic cable payout systems have been designed, leveraging other Army programs, and integrated on several ground vehicles. A number of tests have been conducted to prove the viability of fiber optics for UGV datalink applications. These successful tests led to the initiation of the development of miniature fiber optic dispensers for small UGVs. Based on the outcome of the Engineer Urban Robot Concept Experimentation Program (URBOT CEP) conducted at Ft. Leonard Wood, MO in 1999 that focused on the feasibility, capability, efficiencies and operational effectiveness of small robots for reconnaissance of bunkers, subterranean sewers and tunnels, and Military Operations in Urban Terrain (MOUT), a design concept was formulated for small robot tethered communications. Miniature fiber optic dispensers have now been fabricated and tested. This paper will present a brief history of the technology transfer and development associated with fiber optic datalinks for unmanned ground vehicles and will focus on the recent research and development of miniaturized deployment systems for small robot applications.
The recent progress of ongoing efforts at the Army Aviation and Missile Command (AMCOM) to develop microelectromechanical systems (MEMS) technology for military applications is discussed in this paper. The current maturity level of low cost, low power, micro devices in industry, which range from simple temperature and pressure sensors to accelerometers in airbags, provides a viable foundation for the development of rugged MEMS devices for dual-use applications. Early MEMS technology development efforts at AMCOM emphasized inertial MEMS sensors. An Army Science and Technology Objective (STO) project was initiated to develop low cost inertial components with moderate angular rate sensor resolution for measuring pitch and yaw of missile attitude and rotational roll rate. Leveraging the Defense Advanced Research Projects Agency and other Government agencies has resulted in the development of breadboard inertial MEMS devices with improved robustness. During the past two years, MEMS research at AMCOM has been expanded to include environmental MEMS sensors for missile health monitoring, RF-MEMS, optical MEMS devices for beam steering, and micro-optic 'benches' for opto-electronics miniaturization. Additionally, MEMS packaging and integration issues have come into focus and are being addressed. Selected ongoing research efforts in these areas are presented, and some horizon MEMS sensors requirements for Army and law enforcement are presented for consideration.
Results of an application of fiber-optic Bragg gratings for sensing longitudinal strain in a fiberoptic
coil with 18 layers is described. Some of the fiber winding parameters in this test coil resembled those
typically used in a fiber-optic data link payout dispensers. 9t and 10th layers of this coil have Bragg
gratings in their center with unstrained Bragg wavelengths of 1294.74 and 1285.47 nm respectively. Bragg
grating-based technique is used to measure longitudinal stretch or compression in specific layers of optical
fiber in the coil, and relate it to the various winding parameters like the number of turns above and below
the turn of interest as well as the winding tension in each turn. The observed results are compared to a
cable-pack mechanics model (CPMM) that is widely used in the design of such coils.
In this paper, the nondestructive, nonlinear distributed- strain sensing technique known as Brillouin Optical Time Domain Reflectometry (BOTDR) is described. The strain distributions along optical fibers wound in precision configurations are measured and analyzed using a recently developed commercial-off-the-shelf BOTDR system. Determinations of sensitivity and spatial resolution are made for the instrument. Measurement comparisons to an analytical model are made for the wound fiber packs. Characterizations of measurements of certain geometric configurations and deformity phenomena are expressed. Assessment of the applicability of the technique to reliability predictions for precision-wound fiber optic dispensers and fiber optic gyroscopes is made.
By implicit camera calibration, we mean the process of calibrating cameras without explicitly computing their physical parameters. We introduce a new implicit model based on a generalized mapping between an image plane and multiple, parallel calibration planes (usually between four to seven planes). This paper presents a method of computing a relationship between a point on a three-dimensional (3D) object and its corresponding two-dimensional (2D) coordinate in a camera image. This relationship is expanded to form a mapping of points in 3D space to points in image (camera) space and visa versa that requires only matrix multiplication operations. This paper presents the rationale behind the selection of the forms of four matrices and the algorithms to calculate the parameters for the matrices. Two of the matrices are used to map 3D points in object space to 2D points on the CCD camera image plane. The other two matrices are used to map 2D points on the image plane to points on user defined planes in 3D object space. The mappings include compensation for lens distortion and measurement errors. The number of parameters used can be increased, in a straight forward fashion, to calculate and use as many parameters as needed to obtain a user desired accuracy. Previous methods of camera calibration use a fixed number of parameters which can limit the obtainable accuracy and most require the solution of nonlinear equations. The procedure presented can be used to calibrate a single camera to make 2D measurements or calibrate stereo cameras to make 3D measurements. Positional accuracy of better than 3 parts in 10,000 have been achieved. The algorithms in this paper were developed and are implemented in MATLABR (registered trademark of The Math Works, Inc.). We have developed a system to analyze the path of optical fiber during high speed payout (unwinding) of optical fiber off a bobbin. This requires recording and analyzing high speed (5 microsecond exposure time), synchronous, stereo images of the optical fiber during payout. A 3D equation for the fiber at an instant in time is calculated from the corresponding pair of stereo images as follows. In each image, about 20 points along the 2D projection of the fiber are located. Each of these 'fiber points' in one image is mapped to its projection line in 3D space. Each projection line is mapped into another line in the second image. The intersection of each mapped projection line and a curve fitted to the fiber points of the second image (fiber projection in second image) is calculated. Each intersection point is mapped back to the 3D space. A 3D fiber coordinate is formed from the intersection, in 3D space, of a mapped intersection point with its corresponding projection line. The 3D equation for the fiber is computed from this ordered list of 3D coordinates. This process requires a method of accurately mapping 2D (image space) to 3D (object space) and visa versa.3173
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.