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This article presents a 2-D inclinometer consisting of two individual sensors oriented orthogonally to one another such that each sensor measures the tilt angle along its respective axis. The sensors are constructed using a combination of a half-wavelength microstrip transmission line on a printed circuit board and a rotating transmission line on an overlapping circuit board. As the inclination angle changes, the overall length of the resonator varies, leading to a shift in the resonance wavelength. This wavelength shift accurately represents the inclination variation. The experimental results demonstrate a sensitivity of 0.507 mm/° and a resolution of 0.029° for the sensor. The inclinometer offers a wide dynamic tilt angle measurement range of at least 80° (±40°) along any axis in XY plane. Additionally, the proposed inclinometer exhibits simplicity, cost-effectiveness, and robustness.

In this article, a new inclinometer concept based on an angular half-wavelength microstrip resonator is presented. The inclinometer has a wide dynamic range of 84° (B142°) which can be extended to 180° through a simple modification. The inclinometer is composed of a microstrip transmission line resonator on printed circuit board and a second transmission line on an overlapping circuit board that rotates according to the inclination angle. As the inclination angle changes, the overall length of the resonator varies and leads to resonance frequency shift, which is transformed into inclination variation. The sensor measurements results determined the sensitivity of the sensor as 0.384 mm/° and the resolution as 0.035°. The proposed sensor is also quite simple, cost-effective, compact, and robust.

This study presents capacitive-type inclinometers composed of flexible polymer pillars and dome-shaped roof frames that were manufactured using the three-dimensional (3D) printing method. Polylactic acid (PLA) filaments and acrylonitrile butadiene styrene (ABS) filaments were printed by the fused deposition modeling type 3D printer to fabricate the dome-shaped roof frames and the polymer curing molds, respectively. The operating principle of the inclinometer was to detect the change in capacitance between the helix-shaped electrode coiled around the polymer pillar and the built-in electrode in the roof frame. When the inclinometer was tilted, the polymer pillar was bent, and the physical distance between each electrode was changed with respect to the tilt angle and direction. Therefore, the tilt angles and directions were simultaneously estimated by distinguishing the capacitance and peak capacitance, respectively. The results of the experiments revealed that the inclinometer using the polymer pillar that was electrically connected to a standard weight and the roof frame with a roof angle of 45° exhibited a higher sensitivity (1.391 pF at a tilt angle of 40°) compared to those using roof angles of 90° and 135°. This study supports the use of 3D printing technology for the facile manufacturing of inclinometers that can detect tilt angles and directions simultaneously, which is not achievable with conventional inclinometers.

For the past 50 years, open-ended coaxial lines were commonly employed for the determination of electromagnetic properties of various materials. In this article, the application of an open-ended hollow coaxial cable resonator (OE-HCCR) as a 1-D inclinometer for tilt measurements with 110 nanoradian (nrad) resolution is proposed and demonstrated. The coaxial cable resonant structure is formed between a metal post welded within the coaxial cable at the RF input end and the open end of the coaxial cable. A metal mass block, suspended in proximity to the open end in parallel is used to construct a pendulum structure, serving as the element responsive to a tilt. When the device is tilted, the distance between the mass block and the open end varies due to the displacement of the suspended pendulum. The change in the gap distance modifies the phase reflection coefficient associated with the open end, causing the resonance frequency of the coaxial cable resonator to change. By tracking the resonance frequency, the coaxial line resonator is effectively used as an inclinometer. The experimental results demonstrated that the novel device has a measurement resolution of 110 nrad over a range of 0–3 milliradians (mrad). Additionally, based on the same principle, a 2-D inclinometer based on two perpendicularly aligned OE-HCCRs, useful for simultaneous tilt measurements in two orthogonal dimensions is demonstrated. The open-ended coaxial cable resonator-based inclinometer holds several advantages, including high resolution, robustness, cost effectiveness, ease of signal interrogation, and user-configurable sensitivity and dynamic range. [ABSTRACT FROM AUTHOR]

A Fiber Bragg Grating (FBG)-based inclinometer has been developed for field use, designed to incorporate biaxial 3-dimensional (3D) printed tilt sensors (in which four FBGs were used). The inclinometer was characterized by examining its response to a wide range of tilts, over the range from 0° to 90°, towards the inclination axes. An excellent linear correlation between the wavelength shifts and the inclination angle (up to the 90° used) was obtained, showing an average sensitivity of 0.01 nm per degree of inclination angle, for each of the FBGs used. In addition to the four FBGs that form the basis of the inclination measurement, a further FBG was included in the design to allow compensation for any temperature changes experienced during the measurements. The device was calibrated over the range from −25°C to 80°C (corresponding to the extremes of cold and hot weather conditions likely to be experienced in-the-field), and a sensitivity to temperature change of 0.011nm/°C was achieved, allowing an effective temperature correction to be applied. The data obtained from a full characterization of the performance of the sensor system, carried out in a stable, controlled environment, indicate that this inclinometer yields good sensitivity, making it highly applicable for use in monitoring rapid ground movements and deformations with its compact design allowing its wide use. [ABSTRACT FROM AUTHOR]

Most of the dam’s disasters that occurred in the world could be avoided if proper and preventive measures were taken, such as long-term surface or underground monitoring to detect small soil displacements. However, due to the complex operation necessary to monitor underground layer displacements, inclinometers are not used with suitable regularity. To circumvent the logistics of field campaigns necessary in conventional inclinometers, a real-time, remote monitoring system was developed. In this paper, a fiberoptic inclinometer system was designed, consisting of FBGs arrays fixed along a flexible tube to be inserted into conventional boreholes to monitor underground layers displacements. Tests on the bench consisted of applying lateral displacements to curve the tube with the Bragg wavelengths acquired by an FBG interrogator. Then, a specially developed algorithm, applying the Frenet-Serret equations, and the cubic spline interpolation method were used to reconstruct the tube profile. For the first validation of the proposed method, the algorithm was applied to real data obtained in-field by a conventional inclinometer. The results of these tests showed a good agreement between the curve reconstruction and the plotted data of field measurements. The final validation was performed by applying lateral displacements to the instrumented tube and comparing the real tube profile measured by a laser ruler with the calculated profile by the algorithm. The errors found in all tests were less than 1% attesting that the proposed system can be an alternative methodology to the conventional techniques of geotechnical instrumentation, through continuous monitoring with fast response and in real-time, with possible application to quantify the mass movement of soils; movements from earth dams, landfills, and slopes. [ABSTRACT FROM AUTHOR]

The existing slope safety monitoring studies mainly focus on long-term monitoring of slowly evolving horizontal deformations. However, during the practical applications, sudden deformations may also lead to landslides due to the natural and man-made trigger factors. This article first proposes a reusable and distributed fiber Bragg grating (FBG) inclinometer for simultaneous measurement of horizontal deformation and vibration induced by sudden deformation, providing more extensive monitoring for slopes. The proposed inclinometer utilizes ten FBG tilt sensors in series as measuring elements, which are characterized by easy installation and removal, thus making them reusable and eliminating excessive waste. A signal decomposition method is presented for splitting the coupled signal of the tilt sensor into two parts: the inclination angle signal and the vibration signal. The inclination angle signals can be converted to distributed horizontal deformation through a cumulative algorithm. And the vibration intensity can be inferred from the vibration signal. The measuring principle, structure design, and calibration experiment of the inclinometer were present in detail. A distributed horizontal deformation generating device with high precision was specially developed to simulate the internal deformation of slope. Verification experiments further validated the feasibility of the proposed inclinometer for simultaneous measurement of horizontal deformation and vibration induced by sudden deformation. [ABSTRACT FROM AUTHOR]

This article addresses the analysis and design of a high-resolution and temperature-insensitive inclination sensor using fiber Bragg grating (FBG). The sensor uses a pendulum-based structure with FBG attached to its cantilever arm. Initially, strain analysis of the proposed inclination sensor is carried out using the finite-element method (FEM) to optimize the structure and materials for its fabrication. Experimental analysis is carried out on the inclination sensors by varying the inclination angle, and its results are compared with the FEM-based results. The shift in Bragg wavelength of FBG due to the generated strain at the cantilever arm is observed on optical interrogator. To measure the subpicometer wavelength shift with enhanced resolution and lower uncertainty, eigen decomposition of the reflection spectrum using Karhunen–Loève transform (KLT) is implemented. The range of measurement of tilt angle is found to be 0°–3° with a resolution of 0.0008°. The satisfactory linearity of the measured angle versus true angle, excellent repeatability, and very high resolution validates the feasibility of the proposed inclination sensor. [ABSTRACT FROM AUTHOR]

We report and demonstrate a high-resolution extrinsic Fabry–Perot interferometer (EFPI)-based 2-D fiber optic inclinometer for tilt measurements in two orthogonal dimensions. The inclinometer consists of a pair of perpendicularly arranged EFPI sensors packaged inside a rectangular container box. A triangular-shaped metal prism is attached to the top plate of the container box by three ropes with identical lengths. Two optical fibers are rigidly connected to the top plate of the container box by two supporting rods, respectively. Therefore, two EFPI sensors are formed between the endfaces of two optical fibers and their corresponding side face mirrors. The prism is connected to a cross paddle, which is immersed in a damping fluid to reduce the influence of deleterious vibrations. After tilting, the two reflectors of each EFPI sensor will remain parallel, while the cavity lengths of the EFPI sensors change. Changes in the cavity lengths can be calculated, and the 2-D tilt angles of the inclinometer can be calculated according to the Fabry–Perot principle. The design of the sensor and the measurement principles are discussed. Measurements of the tilt angles of a simply supported beam induced by small loads are presented to verify the tip-angle resolution and uncertainty of the two EFPI sensors in our 2-D inclinometer. The results show the capability for metering tilt angles with high resolution. The 2-D inclinometer was used to continuously monitor the tilt angle of a gravity dam for a one-year period, showing excellent stability and practicability. [ABSTRACT FROM AUTHOR]

In this article, a novel inclinometer exploiting a magnetic fluid as the inertial mass and an optical readout strategy is addressed. In particular, the device behavior has been modeled and experimentally observed by means of a dedicated set-up. The proposed inclinometer uses a 5-mm diameter glass pipe filled with water and a drop of ferrofluid (FF), a retaining mechanism based on a permanent magnet and an infrared (IR) readout strategy. The latter is used to measure the position of the inertial mass inside the pipe, which strictly correlated with the sensor inclination. The main outcomes of the proposed sensing solution consist of the use of a passive restoring mechanism and an IR sensing strategy, which are convenient in terms of power budget with respect to sensors exploiting an electromagnetic readout strategy and a powered restoring mechanism acting on the inertial mass. The developed lab-scale prototype exhibits an operating range of ±15°, a responsivity of 0.56 V/°, and a resolution of 0.25°, as well as a span-to-threshold value of 120. [ABSTRACT FROM AUTHOR]

This paper proposes a low-cost and full 360° measurement range inclinometer based on fluidic motion. The inclinometer is fabricated using printed circuit board manufacturing techniques. The principle is via measuring two channels of capacitance changes between three plates, which are partially filled with nonconductive liquid to obtain two amplitude modulation quadrature signals as the resolver. In this inclinometer, the electrode subdivision is changed from the traditional radial direction to a circumferential direction by a triple-eccentric-ring sensing element to achieve full-range measurement capability from 0° to 360°. In addition, the application of a differential detection scheme leads to the dc capacitance C0 being eliminated in the measurement, resulting a high voltage-to-capacitance ratio in a low voltage source requirement. Both analytical calculation and finite-element analysis verified the feasibility of the principle. Furthermore, nonlinear error simulation is conducted and the main effected reason is figured out. Finally, a prototype is fabricated and assembled. Experimental results show that sensor can measure the tilt angle in a range of 360°, with an accuracy of 0.1° and a resolution better than 0.01°. [ABSTRACT FROM AUTHOR]

The inclinometer is one of the most important instruments used in geotechnical engineering. The inclinometer is installed into a borehole to monitor the angle of inclination at regular intervals along the borehole to profile the land/soil displacement. In this paper, a novel design of an in-place inclinometer utilizing fiber Bragg grating (FBG) sensor technology is presented. The presented inclinometer is highly sensitive and has an angle measurement resolution of 0.006°. The conventional inclinometers may be twisted involuntarily due to the force that they experience during installation. This twisting may hamper the measurement accuracy of inclinometers. The performance of the proposed FBG-based in-place inclinometer is independent of twisting; hence, its accuracy remains intact even if it is twisted. [ABSTRACT FROM AUTHOR]

Design, analysis, simulation, and fabrication of a novel MEMS capacitive inclination sensor is reported. Through precise analysis, a linear relationship between output capacitance and the inclination angle of the structure is extracted which is attributed to the parallel plate structure of the capacitance sensor and tilt-dependent movement of the dielectric liquid at various angles. Our proposed inclinometer has three structures with 1, 2, and 4 parallel plate micro capacitors in each configuration. Capacitors in different structures have a common plate while other plates are separate, so different capacitors are realized. The sensor cavity is cylindrical and is half filled with silicone oil. Tilt application to the sensor leads to oil movement in the cavity and variation of different capacitors in the structure. For an analytical expression, we introduce $C_{\mathrm {out}}$ as a function of different capacitors in each structure to obtain a linear and continuous relation with tilt. Furthermore, we simulate each structure using COMSOL Multiphysics and then test the fabricated samples. Extracted results from analysis, simulation, and performance tests are in a good accordance. Obtained results reveal that the double capacitor structure has a high sensitivity of 32.2 mV/° in the range of ±90° while four-capacitor structure has a measurement range of ±180° (full turnover) with a sensitivity of 10.1 mV/°. High sensitivity, wide linear range besides simplicity of the structure, are advantages of the proposed inclination micro-sensor. [ABSTRACT FROM AUTHOR]

A highly sensitive and simple all-fiber interferometric two-dimensional (2D) bending vector sensor is demonstrated. Fiber interferometer works in reflection mode and formed by manually splicing a small section of elliptic two-core photonic crystal fiber at the end of a single-mode fiber. Due to the birefringence nature of the two cores, the fiber device exhibits orientation-dependent bend sensitivity which is different for different polarization states. A high sensitivity of 6.49 nm/mm is achieved for bending along the x-direction, and the rms deviations for bending in the x- and y-directions are estimated to be 0.015 and 0.098 mm, respectively, by using the matrix method. The device is immune to bend-induced power fluctuation. [ABSTRACT FROM AUTHOR]

Recent advances in wearable computing ask for bendable and conformable electronic circuits and sensors, allowing an easy integration into everyday life objects. Here, we present a novel flexible tilt sensor on plastic using conductive microspheres as gravity sensitive pendulum. The sensor provides a digital output of the measurement signal without the need for any additional electronics (e.g., amplifiers) close to the sensing structure. The sensor is fabricated on a free-standing polyimide foil with SU-8 photoresist defining the cavity for the pendulum. The pendulum consists of freely movable conductive microspheres which, depending on the sense of gravity, connect different electric contacts patterned on the polyimide foil. We develop a model of the sensor and identify the amount of microspheres as one of the key parameters in the sensor design, which influences the performance of the sensor. The presented tilt sensor with eight contacts achieves an angular resolution of 22.5° with a hysteresis of 10° and less at a tilt of the sensor plane of 50°. Analysis of the microsphere movements reveals a response time of the sensor at ~ 50 ms. [ABSTRACT FROM PUBLISHER]

This paper presents a novel inclinometer based on the second kind of ferrofluid levitation principle. Two rectangular magnets with the opposite poles are fixed at the ends of a non-magnetic retainer to generate a symmetric non-uniform magnetic field. A Hall element is fixed to the inner wall of the container located at the center of two magnets. When the device inclines, the movement of the ferrofluid surrounding the magnets as an inertial mass will change the magnetic field acting on the Hall element. Meanwhile, the Hall element will detect the change of the magnetic field and transmit the signal. Some static and dynamic characterizations of the inclinometer with different geometric parameters are obtained through the theoretical calculation and experimental measurement. The satisfactory linearity and the high sensitivity indicate the feasibility of the ferrofluid inclinometer. [ABSTRACT FROM PUBLISHER]

A new concept for an optical fiber inclinometer based on tapered fiber Bragg grating (TFBG) is presented. The sensor was characterized by the experimental measurement of the dependence of inclination angle on the spectral response in fluctuating temperature conditions. The research showed that the TFBG made it possible to simultaneously measure both the inclination angle and temperature, and to operate as a temperature insensitive 0°–90° tilt sensor, in a different interrogation regime. Inscription of the FBG in the tapered optical fiber section offered not only sensor miniaturization, but also the possibility of temperature sensing by the fiber section adjacent to the inclination area. Moreover, due to the reflective mode of the TFBG, the sensor offers excellent sensitivity due to the double-loss operation. [ABSTRACT FROM PUBLISHER]

High-resolution pull-in-based microelectromechanical system (MEMS) inclinometers are presented in this paper. Pull-in is characterized by the sudden loss of stability in electrostatically actuated parallel-plate structures, and since pull-in voltage is stable and easy to measure, it enables an effective transduction mechanism that does not require complex and stable capacitive readout electronics. The MEMS devices used to test the novel architecture have differential actuation electrodes resulting in two pull-in voltages that change differentially with applied acceleration. Dedicated MEMS microstructures with extra proof mass show high sensitivity; 269 mV/° with a nonlinearity <0.5% FS (Full Scale of ±23°). The measured noise is limited by the actuation mechanism, setting the sensor’s resolution at 75 $\mu$ °; high above state-of-the-art MEMS devices. [2014-0156] [ABSTRACT FROM PUBLISHER]

Goal: Design and development of a linear Kalman filter to create an inertial-based inclinometer targeted to dynamic conditions of motion. Methods: The estimation of the body attitude (i.e., the inclination with respect to the vertical) was treated as a source separation problem to discriminate the gravity and the body acceleration from the specific force measured by a triaxial accelerometer. The sensor fusion between triaxial gyroscope and triaxial accelerometer data was performed using a linear Kalman filter. Wrist-worn inertial measurement unit data from ten participants were acquired while performing two dynamic tasks: 60-s sequence of seven manual activities and 90 s of walking at natural speed. Stereophotogrammetric data were used as a reference. A statistical analysis was performed to assess the significance of the accuracy improvement over state-of-the-art approaches. Results: The proposed method achieved, on an average, a root mean square attitude error of 3.6° and 1.8° in manual activities and locomotion tasks (respectively). The statistical analysis showed that, when compared to few competing methods, the proposed method improved the attitude estimation accuracy. Conclusion: A novel Kalman filter for inertial-based attitude estimation was presented in this study. A significant accuracy improvement was achieved over state-of-the-art approaches, due to a filter design that better matched the basic optimality assumptions of Kalman filtering. Significance: Human motion tracking is the main application field of the proposed method. Accurately discriminating the two components present in the triaxial accelerometer signal is well suited for studying both the rotational and the linear body kinematics. [ABSTRACT FROM AUTHOR]

We propose and experimentally demonstrate a compact temperature-insensitive inclinometer, which is constructed by connecting a chemically etched fiber Bragg grating to a hollow-core fiber filled with tin. The optical power reflected from the grating is linearly proportional to the inclination angle of the grating and can provide a real-time measure of the inclination angle. Our experimental sensor can measure the inclination angle from 0° to 20° with an uncertainty of ±0.35° and negligible temperature interference. [ABSTRACT FROM PUBLISHER]

All-fiber inclinometers and displacement sensors using tunable Mach–Zehnder interferometers with an extinction ratio of >30.4~dB are produced by introducing two abrupt tapers in a short length (<1.4~cm) of highly Er/Yb co-doped fiber. The abrupt tapers partially convert the core mode into cladding modes and interference occurs when the phase difference between the core and cladding modes accumulate to \pi after a certain propagation length. The maximal wavelength shift for the resonant transmission dips can reach 40.8 nm (from 1648 to 1607.2 nm) when the inclination angle, \theta, varies from 0^\circ to 32^\circ. The wavelength shift can reach 26 nm (from 1404.4 to 1430.4 nm) when the compressive strain \varepsilon is 0.004. [ABSTRACT FROM PUBLISHER]

This paper presents a new algebraic framework for modeling structures and computing the reconstruction of curves from local derivatives. This is the fundamental problem behind the use of inclinometers to measure the deformation of structures. A solid theoretical background, with derivations, is provided for the solution of a real and practical measurement problem. The reconstruction problem is solved using matrix algebraic techniques applied to variational calculus. Tikhonov, spectral, and a new regularization technique based on truncated constrained basis functions are implemented. It is proved that the solution of differential equations via basis functions corresponds to computing the spectra of the bending modes with respect to the basis functions used. This insight yields a method of determining the optimal set of basis functions based on spectral compactness. A completely new approach to computing a linear differential operator \bf DB which yields a global estimator is presented. The method is also extended to yield a regularizing linear differential operator. The methods are verified, and the claims made substantiated by extensive numerical simulations including Monte Carlo simulations to verify the susceptibility of the solution to noise. The methods are also applied to a real measurement problem of determining the subsidence of rail track during construction in the vicinity of the track. Simultaneous reconstruction and temporal filtering is implemented. [ABSTRACT FROM AUTHOR]

A compact fiber-optic inclinometer based on a fiber-taper Michelson interferometric sensor is constructed and demonstrated. The sensor consist of a single symmetrically taper waist of 80 \mum distanced 30 mm from the single-mode fiber end-tip right-angled cleaved. The amplitude of the bending angle of the fiber taper interferometer is obtained by passive interferometric interrogation based on the generation of two quadrature phase-shifted signals from two fiber Bragg gratings with different resonant wavelengths. Optical phase-to-bending sensitivity of \sim1.13 rad/degree and a bend angle resolution of \sim0.014 degree/\surd Hz were achieved. [ABSTRACT FROM PUBLISHER]

This paper presents a new triaxial accelerometer calibration method using a mathematical model of six calibration parameters: three gain factors and three biases. The fundamental principle of the proposed calibration method is that the sum of the triaxial accelerometer outputs is equal to the gravity vector when the accelerometer is stationary. The proposed method requires the triaxial accelerometer to be placed in six different tilt angles to estimate the six calibration parameters. Since the mathematical model of the calibration parameters is nonlinear, an iterative method is used. The results are verified via simulations by comparing the estimated gain factors and biases with the true gain factors and biases. The simulation results confirm that the proposed method is applicable in extreme cases where the gain factor is 1000 V/(m/s²) and the bias is ±100 V, as well as the cases where the gain factor is 0.001 V/(m/s²) and the bias is 0 V. The proposed calibration method is also experimentally tested with two different triaxial accelerometers, and the results are validated using a mechanical inclinometer. The experimental results show that the proposed method can accurately estimate gain factors and biases even when the initial guesses are not close to the true values. In addition, the proposed method has a low computational cost because the calculation is simple, and the iterative method usually converges within three iteration steps. The error sources of the experiments are discussed in this paper. [ABSTRACT FROM AUTHOR]

In this paper, an innovative inclinometer exploiting ferrofluids is presented. The device consists of a glass pipe filled with deionized water and a drop of ferrofluid, a coil generating a retaining force on the ferrofluidic drop, a couple of sensing coils detecting the ferrofluidic mass position, and two exciter coils moving the ferrofluidic drop back and forth inside the water at the resonance frequency of the whole system. The device exhibits an intrinsic robustness against inertial shocks. The resonant operation mode represents the main novelty with respect to previous realizations of the ferrofluidic inclinometer presented by the authors. This strategy allows for improving the performances of the inclinometer also in terms of mechanical sensitivity. This paper will focus on the design and experimental characterization of the resonant inclinometer, showing improvements achieved by the resonant configuration with respect to the previous "static implementation" without the exciter coils. [ABSTRACT FROM AUTHOR]

This paper describes a new inclinometer that compensates for ultralow-frequency acceleration disturbances. This inclinometer consists of a low-cost accelerometer, pendulum, and rotary encoder. The key feature of this inclinometer is the estimation method used to calculate the pendulum's inertial angle. We propose two algorithms to estimate the pendulum's angle. Algorithm I uses time-averaged accelerations and some assumptions. Algorithm II applies the pendulum's equation of motion. The results of simulations and experiments confirm that both algorithms can achieve highly accurate level/angle estimations under acceleration disturbance conditions. We apply this inclinometer to an autotracking antenna system for vessels. Time simulations verify its effectiveness. [ABSTRACT FROM AUTHOR]

Abstract-A modular wireless microelectromechanical system (MEMS) inclination sensor system (WMISS) is developed and tested for providing structural health monitoring of large-scale hook structures. The operating principle of a 3-D-MEMS-based dual-axis inclinometer is analyzed. A wireless MEMS sensor is integrated using sensing disposal, wireless communication, and power units. The WMISS is calibrated by using a laser displace- ment sensor in a pendular structure. The maximal error of the wireless MEMS inclination sensor is about 1%. The resolution is ±0.0025°. With the new-type tuned mass damper control module, an experiment on a WMISS for the swing monitoring of a Lanjiang hook model is developed. Experimental results indicate that the developed WMISS is highly precise, convenient, stable, and low cost and has long range, and thus, a WMISS can accurately and conveniently monitor the swing of a Lanjiang hook model. [ABSTRACT FROM AUTHOR]

Friction and stiction problems often occur in microsensors and microactuators. An original solution proposed here consists in diamagnetic levitation above integrated micromagnets. This static, energy free, room temperature levitation is seldom used because of the weakness of the forces involved. However, scale reduction enhances diamagnetic volume forces. Therefore, levitation is easily obtained at the microscale. In this work, the levitation of a microparticle of bismuth is studied. Static and dynamic simulations are presented and confronted to experiments. The static simulations enable one to find the location and to quantify the stability of levitation. Dynamic simulations are required to fully explain the results of the experiments proposed. The structure is then fabricated and successful levitation of bismuth in air and copper and silicon in paramagnetic water is reported. Applications in material conveyance, inertial sensors such as inclinometer or accelerometer are explored. [ABSTRACT FROM AUTHOR]

Inertial transducers based on the use of ferrofluids as inertial mass can be of great interest due to their peculiarities and due to the advantages that they show when compared to traditional devices. Ferrofluids are special solutions of magnetic particles in a carrier liquid whose density and other physical features can be controlled by an external magnetic field. In this paper, the development of a ferrofluidic inclinometer, which exhibits a tunable operating range and a valuable metrological feature and an intrinsic robustness against inertial shocks, is presented. The device consists of one excitation coil and two sensing coils wound around a glass pipe where a drop of ferrofluid is contained in a water environment. The magnetic force, which is induced by the excitation coil, attracts the ferrofluidic mass in a position that depends on the device inclination. The voltage at the output of the two sensing coils is related to the ferrofluidic mass displacement and thus reflects the tilt to be measured. Analytical models, simulations, and experimental results are presented to demonstrate the suitability of the proposed approach. [ABSTRACT FROM AUTHOR]

The K2K experiment at KEK is searching for neutrino oscillations by measuring the neutrino beam flux at both a 1 kilotonne water Cherenkov detector (front detector) close to the neutrino source, and at the Super Kamiokande detector 250 km away. Part of the optical calibration of the front detector is accomplished by transmitting laser light via a fiber optic cable to a light-diffusing ball immersed in the water. A manipulator system has been built to position the ball at various locations within the water volume. A description of the mechanics and the control system is presented. [ABSTRACT FROM AUTHOR]

In this paper, a state estimation technique is developed for sensing inclination angles using low-cost sensors. A low-bandwidth tilt sensor is used along with an inaccurate rate gyro and a low-cost accelerometer to obtain the measurement. The rate gyro has an inherent bias along with sensor noise. The tilt sensor uses an internal pendulum and therefore has its own slow dynamics. These sensor dynamics were identified experimentally and combined to achieve high-bandwidth measurements using an optimal linear state estimator. Potential uses of the measurement technique range from robotics, to rehabilitation, to vehicle control. [ABSTRACT FROM PUBLISHER]

This paper deals with the analytical examination of the dynamic properties of the walking motion of a biped robot based on a simple model. The robot is driven by rhythmic signals from an oscillator, which receives feedback signals from touch sensors at the tips of the legs. Instantly, the oscillator resets its phase and modifies the walking motion according to the feedback signals. Based on such a simple model, approximate periodic solutions are obtained, and the stability of the walking motion is analytically investigated by using a Poincaré map. The analytical results demonstrate that the modification of the step period and the walking motion due to the sensory feedback signals improves the stability of the walking motion. [ABSTRACT FROM AUTHOR]