Motion estimation of a levitation mechanisms using piezoelectric element

We study miniature robots using piezo actuators. We proposed a levitating type miniature robot and a delta-type miniature robot using piezos and electromagnets. We thought that friction force control using levitation mechanism can realize more precise operation, and we proposed delta-type miniature robot using levitation mechanisms. This robot is combined the advantages of the two robots. This robot has three levitation mechanisms using the squeeze film effect. It can realize the linear and rotational displacement by its delta-type structure. Furthermore, its levitation mechanisms can help to decrease the frictional wear between the robot and working surface. In this study, we produce experimentally the L-type miniature robot using levitation mechanisms. This robot also can realize the linear and rotational displacement, and reduce a using piezo.

This paper suggested the soundness monitoring system of livestock facility based on wireless sensor network. Recently, the methods that evaluate the soundness of structure are being researched frequently. The system that forecasts the damaged parts by analyzing the data acquired from the sensor the acceleration sensor combined with GPS sensor and forwards that to the users was suggested in this paper. For that, the integrated sensor and client were designed and implemented and it was checked if the system operates normally through the test. The soundness monitoring system of livestock facility based on wireless sensor network was suggested in this paper. In case of the system that uses optical fiber displacement sensor, the system was implemented by using the bending loss phenomenon of optical fiber to carry out the structure soundness monitoring announced in 2011. Bending loss is the physical phenomenon that the light is lost by bending when the light processes in the straight optical fiber core. The displacement of the structure was estimated in reverse by measuring the strength of bending loss generated from the displacement at the state light intensity that spreads the inside of optical fiber displacement sensor does not have the loss using such phenomenon. And GUI-based real-time monitoring system was developed using LabVIEW software(1)(2). In 2009, the soundness of the bridge was evaluated by using speed & impedance-based wireless sensor nod. The type of damage was analyzed using vibration characteristics acquired from the structure and impedance characteristics acquired from surrounding of tendon and the proper detailed search method was applied along the damage(3)(4). A number of system that manages the specifications or controls the facilities by jointing ICT technology with cattle shed were developed in general. The wireless sensor network-based cattle shed management system that uses bio and environmental sensors suggested the environment monitoring and environment improvement in 2013. The system consists of monitoring nod and environment controlling nod and the effectiveness was evaluated. Now that it enables massive livestock industry environment and environment improvement, real-time data

The paper focuses on analysis of inductive and optical displacement sensors and their use in industrial applications. Differential inductive displacement sensors, usually in the form of linear variable differential transformer LVDT, are widely used in hydraulic applications because they have excellent accuracy, robust construction and are able to measure large displacements (in hundreds of millimeters range). However, they are large, heavy and offer slow measurements. For fast measurements, in millisecond range, optical sensors like time-of-flight ranging sensor could be a better choice, and present paper investigates their performances and compares them in this regard with inductive sensors.

A compact, highly sensitive optical fiber displacement and curvature radius sensor is presented. The device consists of an adiabatic bi-conical fused fiber taper spliced to a single-mode fiber (SMF) segment with a flat face end. The bi-conical taper structure acts as a modal coupling device between core and cladding modes for the SMF segment. When the bi-conical taper is bent by an axial displacement, the symmetrical bi-conical shape of the tapered structure is stressed, causing a change in the refractive index profile which becomes asymmetric. As a result, the taper adiabaticity is lost, and interference between modes appears. As the bending increases, a small change in the fringe visibility and a wavelength shift on the periodical reflection spectrum of the in-fiber interferometer is produced. The displacement sensitivity and the spectral periodicity of the device can be adjusted by the proper selection of the SMF length. Sensitivities from around 1.93 to 3.4 nm/mm were obtained for SMF length between 7.5 and 12.5 cm. Both sensor interrogations, wavelength shift and visibility contrast, can be used to measure displacement and curvature radius magnitudes.

A signal processing method for reflective fiber optic displacement sensor is presented by means of a differential evolution optimized extreme learning machine (DE-ELM). The sensing head of the sensor is a combination of an illuminating fiber bundle transmitting incoming light beam and two receiving fiber bundles employed to collect the reflected beam from the reflector. Three fiber bundles with same type are put together and arranged side by side, but the two receiving fiber bundles enfaces have different distances from the reflector surface. The DE-ELM is used for extending the measuring the range of reflective fiber optic displacement sensor. A simulation experiment has been illustrated. The experimental results show that the measuring range can be extended to the whole response characteristics of the fiber optic displacement sensor and a high measuring accuracy can be obtained by the proposed method.

A Fibre Optic Distributed Differential Displacement Sensor is modelled and experimentally verified to determine shape. Created using a steel tape, 9/125 μm single mode fibre, and adhesive, the FODDDS can be used to determine shape or displacement of any object to which it is bonded. A circular shape is examined, and a radius of curvature comparison yields an error of 2%. The sensitivity of the FODDDS, for the substrate thickness used in this experiment, is shown to be 1.27 mm between adjacent data points, which corresponds to a radius of curvature of 103 m.

A fiber optic rotary displacement sensor has been developed in which an optical retardation plate is used to encode angular displacement on a broadband optical signal as a modulated notch minimum. As the waveplate is rotated, the optical beam experiences a variable linear retardation. The signal wavelength at which the retardation is exactly one-half wave exhibits a minimum intensity transmission. The wavelength of the intensity minimum is then a function of the rotation of the retardation plate. Determination of the wavelength of these intensity minima is based on measurements acquired with a grating-CCD configuration. Source variations (wavelength and power) are monitored by illuminating a portion of the grating-CCD. Normalization is obtained by referencing the modulated signal, obtained from the remaining CCD pixels, to the source emission. A theoretical prediction of the sensor's performance is developed and compared with experiments performed in the near IR spectral region using large core multimode optical fiber. Temperature compensation of the system will also be discussed.

This paper discuss the development of a prototype low-cost portable optical fibre measuring instrument. The instrument employs optoelectronics devices such as light emitting diodes (LEDs) as light sources and semiconductor photodiode (PD) as a photodetector. A fibre optic cable is used as an information signal transmission medium between the light sources, sensors and photodetector. The study focus on the sensors and optical link fabrication and also creating internal reference to correct the variations in light signal intensity due to fibre bending, fibre connection, components degradation and environmental effects. The instrument system has been designed to measure colour variations and physical displacements. It also has computer interfacing facility to linearise the data and create the colour coding.

In this Letter, a long-range optical fiber displacement sensor based on an extrinsic Fabry-Perot interferometer (EFPI) built with a strongly coupled multicore fiber (SCMCF) is proposed and demonstrated. To fabricate the device, 9.2 mm of SCMCF was spliced to a conventional single-mode fiber (SMF). The sensor reflection spectrum is affected by super-mode interference in the SCMCF and the interference produced by the EFPI. Displacement of the SMF-SCMCF tip with respect to a reflecting surface produces quantifiable changes in the amplitude and period of the interference pattern in the reflection spectrum. Since the multicore fiber is an efficient light collecting area, sufficient signal intensity can be obtained for displacements of several centimeters. By analyzing the interference pattern in the Fourier domain, it was possible to measure displacements up to 50 mm with a resolution of approximately 500 nm. To our knowledge, this is the first time that a multicore fiber has been used to build a displacement sensor. The dynamic measurement range is at least seven times larger than that achieved with an EFPI built with a conventional SMF. Moreover, the SMF-SCMCF tip is robust and easy to fabricate and replicate.

We report a low cost and extrinsic Fabry-Perot interferometer-based optical fiber displacement sensor with a wide dynamic range, up to 2.0 cm, and $0.270~\mu \text{m}$ resolution. The fundamental design principle includes an inclined mirror, mounted on a translational stage, that combines with the end face of a single mode fiber to form a Fabry-Perot cavity. The user-configurable triangle geometry-based displacement transfer mechanism makes the sensor capable of measuring a wide displacement range. A fiber ceramic ferrule is used to support and orient the optical fiber, and a metal shell is used to package and protect the principal sensor elements. The novel sensor was employed to monitor shrinkage during the drying/curing stage of a square brick of mortar. The robust and easy-to-manufacture sensor can be easily commercialized and has great potential for applications in the chemical-oil industry, construction industry, and other industries with harsh environments.

Grating displacement sensors are vulnerable to various factors, including mechanical vibrations and temperature fluctuations. These influences can result in cumulative errors in displacement measurements, ultimately compromising the accuracy of the measurements. To address the challenge of time-varying accumulated errors in dynamic measurements using high-precision optical fringe displacement sensors, this paper proposes a dynamic fusion algorithm that integrates Error State Kalman Filtering (ESKF) with dual-parameter adaptive tuning, denoted as ADA-ESKF. This algorithm dynamically tracks and estimates the cumulative error in the measurement process, perceives the residual change trend in real time, and dynamically adjusts the size of the dual noise parameters, achieving adaptive filtering of dynamic noise. This article constructs a dynamic cumulative error compensation model based on error-state Kalman filtering and dual-parameter adaptive adjustment. A comprehensive simulation study, including scenarios with white Gaussian noise and impulsive disturbances, demonstrates that ADA-ESKF outperforms both the Maximum Correntropy Kalman Filter and graph-based optimization in terms of estimation accuracy and robustness to abrupt noise variations, while maintaining computational efficiency suitable for real-time applications. The experimental results show that in multiple sets of displacement measurement experiments with continuous measurement at 20mm, this algorithm has good real-time predictability for cumulative errors. The corrected root mean square error was reduced on average from 1.362 to 0.432μm, with an average decrease of 68.92%. The maximum absolute error was reduced on average from 2.438 to 0.690μm, with an average decrease of 72.25%. Additional tests under varying velocities (0.5-3.0 mm/s) and extended ranges (up to 40mm) confirm the algorithm's adaptability and long-term stability. The proposed ADA-ESKF thus provides an efficient, accurate, and robust solution for real-time cumulative error compensation in high-precision displacement sensors.

In this paper, a study of a low-coherence fiber optic displacement sensor is presented. The sensor consisted of a broadband source whose central wavelength was either at 1310 nm or 1550 nm, a sensing Fabry-Perot interferometer operating in reflective mode and an optical spectrum analyzer acting as the detection setup. All these components were connected by a single-mode fiber coupler. Metrological parameters of the sensor were investigated for different lengths of the fiber connecting the sensing Fabry-Perot interferometer (1 m and 10 m). For each length of the fiber, displacement in the range of 0 μm to 500 μm, in increments of 50 μm were measured. Obtained results indicate that the developed sensor is not sensitive to changes in attenuation in the optical path, thus enabling remote measurement of the displacement on long distances while maintaining a satisfactory accuracy.

A least squares support vector machine (LS-SVM) based signal processing approach of reflective fiber optic displacement sensor is presented. The example for extending measuring range of the sensor using LS-SVM has been illustrated. From the experimental results, it can be clearly seen that not only the measuring range can be extended to the whole response characteristics of the fiber optics displacement sensor effectively, but also a desired linear relationship between the actual displacement and the LS-SVM predicted output can be obtained. This means the method proposed is very effective for the signal processing of the sensor.

Review of fiber optic sensors in geotechnical health monitoring

Fiber optic displacement sensors are widely used in industry due to advantages such as simple design, low cost and immune to RFI and EMI. Non-contact type fiber optic sensors are popularly known as retroreflective type of extrinsic sensors. Due to its inherent advantages, retro reflective extrinsic Fiber optic sensors (FOS) have been examined, statistically modelled, and tested for performance. This paper reports easy pathway to study, analyze and optimize the retroreflective extrinsic type FOS as a software tool ‘FOS Explore’. This tool was created utilizing the ray tracing technique and a generalized mathematical model of FOS. Sensor geometries can be set and performance characteristics can be examined. The software, which was created using MATLAB, allows users to input various fiber specifications and geometrical factors in order to determine the sensor's layout. For ease of comprehension, the simulated results are presented in the form of a tabular display, particular plots, and cross sectional views of sensor geometry. This software program is used to examine and optimize multiple architectures based on performance factors such as sensitivity and linear operating range at certain non linearity, in addition to basic configuration.