Journal articles: 'Linear optical position sensor'

1

Aiestaran, P., V. Dominguez, J. Arrue, and J. Zubia. "A fluorescent linear optical fiber position sensor." Optical Materials 31, no. 7 (May 2009): 1101–4. http://dx.doi.org/10.1016/j.optmat.2007.12.022.

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Kitazono, Yuhki, Shota Nakashima, Li Feng Zhang, and Serikawa Seiichi. "Proposal of an Optical Linear Sensor Using One-Side Frosted Glass." Applied Mechanics and Materials 36 (October 2010): 370–75. http://dx.doi.org/10.4028/www.scientific.net/amm.36.370.

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Sensors that detect the distance and the position of an object are used in a lot of fields. Among of them, the sensors that measure the shift value of an object are a large scale system, furthermore, an accurate mounting of these sensors is required. To solve these problems, this paper proposes an optical linear sensor using one-side frosted glass. This sensor can detect the position of the light irradiation point only by putting it directly on the target. For a parallel light, it is irrelevant to the distance between this sensor and the source of light because the size of light beam is unchanged according to the distance. This sensor assumes that the sensor’s surface irradiated roughly vertical with the light, and does not need a high accurate mounting. Therefore, it can be easily used.

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Tantau, Mathias, Paul Morantz, and Paul Shore. "Position sensor for active magnetic bearing with commercial linear optical encoders." CIRP Annals 70, no. 1 (2021): 419–22. http://dx.doi.org/10.1016/j.cirp.2021.04.092.

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Seco, Fernando, José Miguel Martín, Antonio Ramón Jiménez, and Leopoldo Calderón. "A high accuracy magnetostrictive linear position sensor." Sensors and Actuators A: Physical 123-124 (September 2005): 216–23. http://dx.doi.org/10.1016/j.sna.2005.02.026.

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Lin, Chih-Hong. "Precision Motion Control of a Linear Permanent Magnet Synchronous Machine Based on Linear Optical-Ruler Sensor and Hall Sensor." Sensors 18, no. 10 (October 7, 2018): 3345. http://dx.doi.org/10.3390/s18103345.

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The linear optical-ruler sensor with 1um precision mounted in the linear permanent magnet synchronous machine (LPMSM) is used for measuring the mover position of LPMSM in order to enhance the precision of a measured mover position. Due to nonlinear friction and uncertainty effects, linear controllers are very hard to achieve good mover positioning of LPMSM. The proposed adaptive amended Elman neural network backstepping (AAENNB) control system is adopted for controlling the LPMSM drive system to bring about the mover positioning precision of LPMSM. Firstly, a backstepping scheme is posed for controlling the tracing motion of the LPMSM drive system. The proposed backstepping control system, which is applied in the mover position of the LPMSM drive system, possesses better dynamic control performance and robustness to uncertainties for the tracing trajectories. Because of the LPMSM with nonlinear and time-varying dynamic characteristics, an adaptive amended Elman neural network uncertainty observer (AAENNUO) is posed to estimate the required lumped uncertainty. According to the Lyapunov stability theorem, on-line parameter training methodology of the amended Elman neural network (AENN) can be derived by use of adaptive law. The error estimated law is proposed to compensate for the observed error induced by the AENN with adaptive law. Furthermore, to help improve convergence and to obtain better learning performance, the mended particle swarm optimization (PSO) algorithm is utilized for adjusting the varied learning rate of the weights in the AENN. At last, these experimental results, which show better performance, are verified by the proposed control system.

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Dhawan, Ravi, Rushal Shah, Nitin Kawade, and Biswaranjan Dikshit. "Design and development of linear optical fiber array based remote position sensor." Optik 139 (June 2017): 355–65. http://dx.doi.org/10.1016/j.ijleo.2017.04.036.

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Seco, Fernando, José Miguel Martín, José Luis Pons, and Antonio Ramón Jiménez. "Hysteresis compensation in a magnetostrictive linear position sensor." Sensors and Actuators A: Physical 110, no. 1-3 (February 2004): 247–53. http://dx.doi.org/10.1016/j.sna.2003.09.031.

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Qin, Bo Ying, and Xian Kun Lin. "Application of Integer-Coded Genetic Algorithm to Optimal Sensor Placement." Advanced Materials Research 271-273 (July 2011): 1114–19. http://dx.doi.org/10.4028/www.scientific.net/amr.271-273.1114.

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In the dynamic testing, the sensor positions have a major influence on the quality of the experimental modal parameters of a tested structure. In order to dispose sensors to reasonable degrees of freedom (DOF), and reflect adequately the dynamic characteristics of tested structure, the sensor positions must be optimized. In this paper, taking the combination of MAC matrix and Fisher information matrix (FIM) as optimization criteria, the integer-coded genetic algorithm (IGA) was applied to optimal sensor position problem (OSPP). The effect of optimization criteria and optimal method to optimal sensor positions were discussed. According to the results, the following conclusion is obtained: using MAC and FIM as optimal criteria, introducing the IGA into the OSPP, the optimal sensor positions can ensure the better linear independence of the mode shape vectors and the better estimation of the experimental modal parameters. Comparing with three existing optimal sensor placement methods, which are Guyan, effective independence (EI), and cumulative method based on QR decomposition (CQRD), their results of the optimal sensor positions indicated that the IGA is better than them.

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Liu, Han Bing, Chun Li Wu, and Jing Wang. "Sensor Optimal Placement for Bridge Structure Based on Single Parents Genetic Algorithm with Different Fitness Functions." Key Engineering Materials 456 (December 2010): 115–24. http://dx.doi.org/10.4028/www.scientific.net/kem.456.115.

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An investigation into sensor optimal placement for bridge structure based on Single Parents Genetic Algorithm with different fitness functions has been carried on. Five fitness functions are designed from several aspects on linear independence, orthogonality and energy of mode. The two-step method is proposed to determine the number of sensors firstly and then sensor position. An example of a large span arch bridge has proved the following facts: the Single Parents Genetic Algorithm is quite suitable to sensor optimal placement for bridge structure. Fitness functions designed by effective independence index and MAC and BHM combined index are more desirable than other evaluation indices. Two-step method used to determine the number of sensors and position is very effective.

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Wang, Wen Hua, and Xin Sheng Jiang. "Influence of the Q Point on the Extrinsic Fabry-Perot Interferometer Fiber-Optic Sensors with a Diaphragm." Applied Mechanics and Materials 303-306 (February 2013): 78–81. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.78.

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In this paper, the influence of the Q point on the DEFPI fiber-optic sensors is comprehensively analyses. For a DEFPI fiber-optic sensor, the output signals vary with the different position of the operational point regarding to the same applied pressure. The optimal operational point is in the middle position of the fringe linear scope. In addition, we present a novel structure sensor to guarantee the stableness of the Q point.

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Rybarczyk, Dominik. "Application of the MEMS Accelerometer as the Position Sensor in Linear Electrohydraulic Drive." Sensors 21, no. 4 (February 20, 2021): 1479. http://dx.doi.org/10.3390/s21041479.

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Various distance sensors are used as measuring elements for positioning linear electrohydraulic drives. The most common are magnetostrictive transducers or linear variable differential transformer (LVDT) sensors mounted inside the cylinder. The displacement of the actuator’s piston rod is proportional to the change in the value of the current or voltage at the output from the sensor. They are characterized by relatively low measurement noise. The disadvantage of presented sensors is the need to mount them inside the cylinders and the high price. The article presents preliminary research on the replacement of following sensors and the use of a microelectromechanical system (MEMS) accelerometer as a measuring element in the electrohydraulic drive control system. The control consisted of two phases: at first, the signal from the acceleration sensor was analyzed during the actuator movement, based on the value determined from the simplified model implemented on the controller. In the range of motion in which the dynamics were the lowest, the signal was integrated and the obtained value was used in the second phase of motion. In the correction phase, a new set point was determined. Conducting the research required building a dedicated research stand. The author conducted the simulation and experimental research.

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Yang, Dong, Jin-Qi Wang, Wei-Xin Ren, and Jing Zhang. "A Plastic Optical Fiber Sensing System for Bridge Deflection Measurement." Sensors 20, no. 2 (January 15, 2020): 480. http://dx.doi.org/10.3390/s20020480.

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Deflection is one of the key parameters that reflects the state of a bridge. However, deflection measurement is difficult for a bridge that is under operation. Most existing sensors and measuring techniques often do not meet the requirements for health monitoring for various types of bridges. Therefore, based on changes of optical fiber intensity, a novel sensing system using connected pipes to measure bridge deflection in different positions is proposed in this paper. As an absolute reference, the liquid level position along the structure is adopted for the deflection measurement, and an additional external reference to the ground is not needed in this system. The proposed system consists of three parts: connected pipes to connect the measurement points along the structure, liquid to fill in the connected pipes, and the sensing element to detect the change of level. A plastic optical fiber sensor based on the intensity change is used as the sensing element of the developed system. Then, a set of experimental tests are conducted for performance evaluation purposes. Results show that this system has an accurate linear response and high reliability under various environmental conditions. The deflection of the test beam measured by the sensor agrees with linear variable differential transformer (LVDT) within an error margin of 2.1%. The proposed system shows great potential applicability for future health monitoring of long-span bridges.

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Fu, Cheng, Tjahjowidodo, and Liu. "Development of an Image Grating Sensor for Position Measurement." Sensors 19, no. 22 (November 15, 2019): 4986. http://dx.doi.org/10.3390/s19224986.

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In this research paper, a precision position-measurement system based on the image grating technique is presented. The system offers a better robustness and flexibility for 1D position measurement compared to a conventional optical encoder. It is equipped with an image grating attached to a linear stage as the target feature and a line scan camera as the stationary displacement reader. By measuring the position of the specific feature in the image and applying a subpixel image registration method, the position of the linear stage can be obtained. In order to improve the computational efficiency, the calculations for pattern correlation and subpixel registration are performed in the frequency domain. An error compensation method based on a lens distortion model is investigated and implemented to improve the measurement accuracy of the proposed system. Experimental data confirms the capability of the developed image grating system as ±0.3 µm measurement accuracy within a 50 mm range and ±0.2 µm measurement accuracy within a 25 mm range. By applying different optics, the standoff distance, measurement range, and resolution can be customized to conform to different precision measurement applications.

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Lu, Yifan, Marco Amabili, Jian Wang, Fei Yang, Honghao Yue, Ye Xu, and Hornsen Tzou. "Active vibration control of a polyvinylidene fluoride laminated membrane plate mirror." Journal of Vibration and Control 25, no. 19-20 (July 11, 2019): 2611–26. http://dx.doi.org/10.1177/1077546319862445.

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Lightweight optical mirrors usually play key roles in aerospace and optical structural systems applied to space telescopes, radars, solar collectors, communication antennas, etc. Due to their high flexibility and low damping properties, external excitations such as orbital maneuver may induce unexpected oscillations and thus reduce their working performance. Active vibration control is therefore essential for the lightweight optical mirror systems. In this spirit, a lightweight mirror structronic system with a linear quadratic optimal controller is presented. The mirror is modeled as a membrane plate with pretension and distributed polyvinylidene fluoride sensors and actuators. The sensing sensitivity of the piezoelectric (PVDF) sensors and the modal actuation factor of the PVDF actuators are derived. The state-space equations are established and the feedback control gains between sensing and control signals are obtained. Sensor and actuator of different shape, size, and position are employed to actively control the first four natural modes of the mirror. The influences of mode order, pretension, and the two weighting factors Q and R on the control performance are also investigated. Analytical results in this paper could guide the design and layout of the PZT sensor and actuator on lightweight membrane plate mirrors.

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Odinokov, Sergey, Maria Shishova, Michael Kovalev, Alexander Zherdev, and Dmitrii Lushnikov. "Phase Imbalance Optimization in Interference Linear Displacement Sensor with Surface Gratings." Sensors 20, no. 5 (March 6, 2020): 1453. http://dx.doi.org/10.3390/s20051453.

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In interferential linear displacement sensors, accurate information about the position of the reading head is calculated out of a pair of quadrature (sine and cosine) signals. In double grating interference schemes, diffraction gratings combine the function of beam splitters and phase retardation devices. Specifically, the reference diffraction grating is located in the reading head and regulates the phase shifts in diffraction orders. Measurement diffraction grating moves along with the object and provides correspondence to the displacement coordinate. To stabilize the phase imbalance in the output quadrature signals of the sensor, we propose to calculate and optimize the parameters of these gratings, based not only on the energetic analysis, but along with phase relationships in diffraction orders. The optimization method is based on rigorous coupled-wave analysis simulation of the phase shifts of light in diffraction orders in the optical system. The phase properties of the reference diffraction grating in the interferential sensor are studied. It is confirmed that the possibility of quadrature modulation depends on parameters of static reference scale. The implemented optimization criteria are formulated in accordance with the signal generation process in the optical branch. Phase imbalance and amplification coefficients are derived from Heydemann elliptic correction and expressed through the diffraction efficiencies and phase retardations of the reference scale. The phase imbalance of the obtained quadrature signals is estimated in ellipticity correction terms depending on the uncertainties of influencing parameters.

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Sysoev, Evgeny V., Yuri V. Chugui, Rodion V. Kulikov, Ignat A. Vykhristyuk, Liang Chia Chen, Hoang Hong Hai, and Kuang Chao Fan. "Application of 3D Nanorelief Sharp-Edge Detection Method in the Optical Interference Microscope." Applied Mechanics and Materials 870 (September 2017): 34–40. http://dx.doi.org/10.4028/www.scientific.net/amm.870.34.

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As is well known, the phase-shifting interferometry techniques allow to reach longitudinal resolution to ~ 0.1 nm, but the value of lateral resolution remains at the level of ~ 1 mm. For providing of high lateral resolution of linear measurements in the interference microscope profilometer it was proposed to use a position detection sensor of sharp edge. Principle of sensor’s measurement is based on registration of laser spot intensity scattered by the measurement sample surface under displacement of sample in the lateral direction. The paper shows the prototype scheme of measurement system containing the Linnik interferometer used for surface nanorelief measurement and a position detection module of sharp edge. Measurement process and experimental results are presented. The combining of measurement results performed by the Linnik interferometer and a position detection sensor of sharp edge can allow us to precisely (better then diffraction limit) define the position of sharp edge on the reconstructed surface nanorelief.

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Brenan, Colin J. H., Tilemachos D. Doukoglou, Ian W. Hunter, and Serge Lafontaine. "Characterization and use of a novel optical position sensor for microposition control of a linear motor." Review of Scientific Instruments 64, no. 2 (February 1993): 349–56. http://dx.doi.org/10.1063/1.1144256.

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Bošnak, Matevž, and Gregor Klančar. "Fast and Reliable Alternative to Encoder-Based Measurements of Multiple 2-DOF Rotary-Linear Transformable Objects Using a Network of Image Sensors with Application to Table Football." Sensors 20, no. 12 (June 23, 2020): 3552. http://dx.doi.org/10.3390/s20123552.

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Simultaneous determination of linear and angular positions of rotating objects is a challenging task for traditional sensor applications and a very limited set of solutions is available. The paper presents a novel approach of replacing a set of traditional linear and rotational sensors by a small set of image sensors. While the camera’s angle of view can be a limiting factor in the tracking of multiple objects, the presented approach allows for a network of image sensors to extend the covered area. Furthermore, rich image data allows for the application of different data processing algorithms to effectively and accurately determine the object’s position. The proposed solution thus provides a set of smart visual encoders emulated by an image sensor or a network of image sensors for more demanding spatially distributed tasks. As a proof of concept, we present the results of the experiment in the target application, where a 1.6 MP image sensor was used to obtain sub-degree angular resolution at 600 rpm and thus exceeding the design parameters and requirements. The solution allows for a compact, cost-effective, and robust integration into the final product.

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Arana, S., N. Arana, F. J. Gracia, and E. Castaño. "High sensitivity linear position sensor developed using granular Ag–Co giant magnetoresistances." Sensors and Actuators A: Physical 123-124 (September 2005): 116–21. http://dx.doi.org/10.1016/j.sna.2005.04.002.

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Ortner, Michael, Marcelo Ribeiro, and Dietmar Spitzer. "Absolute Long-Range Linear Position System With a Single 3-D Magnetic Field Sensor." IEEE Transactions on Magnetics 55, no. 1 (January 2019): 1–4. http://dx.doi.org/10.1109/tmag.2018.2870597.

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Wang, Chuang, Li Xing, and Xiaowei Tu. "A Novel Position and Orientation Sensor for Indoor Navigation Based on Linear CCDs." Sensors 20, no. 3 (January 29, 2020): 748. http://dx.doi.org/10.3390/s20030748.

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The position and orientation of a mobile agent, such as robot or drone, etc., should be estimated in a timely way during operation in the structured indoor environment, so as to ensure the security and efficiency of task execution. Concerning the problem that the position and orientation are often estimated separately by different kinds of sensors in the off-the-shelf methods, we design a novel position orientation sensor (POS). The POS consists of four pairs of linear charge-coupled devices (CCDs) and cylindrical lenses, which can estimate the 3D coordinate of the anchor in the POS’s field of view. After detecting at least three anchors in its field of vision sequentially, the Rodrigues coordinate transformation algorithm is utilized to estimate the position and orientation of POS simultaneously. Meanwhile, the position and orientation are estimated at the receiver side. Hence there is no privacy concern associated with this system. The architecture of the proposed POS is symmetrical and redundant, even if one of the linear CCDs or cylindrical lens malfunctions, the whole system could still work normally. The proposed method is cost-effective and easily extends to a wide range. The numerical simulation demonstrates the feasibility and high accuracy of the proposed method, and it outperforms the off-the-shelf methods.

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Prada, Erik. "DETERMINATION OF TRANSFER FUNCTION OF MAGNETIC LEVITATION MODEL AND EXPERIMENTAL VERIFICATION OF OPTICAL SENSOR." TECHNICAL SCIENCES AND TECHNOLOGIES, no. 4(18) (2019): 148–54. http://dx.doi.org/10.25140/2411-5363-2019-4(18)-148-154.

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Urgency of the research. The potential of controlling the position of levitating objects has great application in deposition and in various positioning systems. Magnetic levitation eliminates direct mechanical friction between moving parts. Target setting. The measurement shielding method used is one of the methods of determining the position of a levitating object. By combining positioning and regulating elements, we achieve a feedback control. The use of a given type of measurement has advantages in places where the use of other methods is not appropriate. Actual scientific researches and issues analysis. The problem of magnetic levitation is addressed by several research laboratories with a direct connection to practice. The problem that is currently solved within magnetic levitation is the regulation of the levitating object using various types of regulators. The research objective. Derivation of mathematical model of magnetic levitation and examination of nonlinear system followed by linearization by Taylor series. Experimental determination of characteristics and dependence between object position, voltage and current. The statement of basic materials. The position of the levitating object is determined by the shading of the optical sensor. The light source is a laser light. Conclusions. In this work we defined the mathematical model of the magnetic levitation system and subsequently derived the transfer function of the levitation system and the position sensor. From the experimental verification of the shadow method for the determination of the position of the levitating object and the consequent need for regulation, we found that the dependence of the position of the levitating object on current and voltage on the photodiode is linear in the active region.

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Paredes, Ferran, Cristian Herrojo, and Ferran Martín. "Position Sensors for Industrial Applications Based on Electromagnetic Encoders." Sensors 21, no. 8 (April 13, 2021): 2738. http://dx.doi.org/10.3390/s21082738.

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Optical and magnetic linear/rotary encoders are well-known systems traditionally used in industry for the accurate measurement of linear/angular displacements and velocities. Recently, a different approach for the implementation of linear/rotary encoders has been proposed. Such an approach uses electromagnetic signals, and the working principle of these electromagnetic encoders is very similar to the one of optical encoders, i.e., pulse counting. Specifically, a transmission line based structure fed by a harmonic signal tuned to a certain frequency, the stator, is perturbed by encoder motion. Such encoder consists in a linear or circular chain (or chains) of inclusions (metallic, dielectric, or apertures) on a dielectric substrate, rigid or flexible, and made of different materials, including plastics, organic materials, rubber, etc. The harmonic signal is amplitude modulated by the encoder chain, and the envelope function contains the information relative to the position and velocity. The paper mainly focuses on linear encoders based on metallic and dielectric inclusions. Moreover, it is shown that synchronous electromagnetic encoders, able to provide the quasi-absolute position (plus the velocity and direction of motion in some cases), can be implemented. Several prototype examples are reviewed in the paper, including encoders implemented by means of additive process, such as 3D printed and screen-printed encoders.

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Shams, I., H. Rahnejat, and D. Greening. "A Non-Contact Opto-Electronic Sensing Device for Precision Linear and Angular Positioning of Robotic Manipulators." Proceedings of the Institution of Mechanical Engineers, Part B: Management and engineering manufacture 202, no. 4 (November 1988): 261–65. http://dx.doi.org/10.1243/pime_proc_1988_202_076_02.

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A non-contacting optical sensor is devised to monitor the position and orientation of a robot end-effector or grasped object within fine limits of accuracy. This enables fine alignment of tools or parts with respect to assembly fixtures, thus rendering precision assembly tasks to be performed in a dexterous manner. The sensor is capable of detecting linear displacements of the order of 5 μm or better and angular misalignments down to 5 seconds of arc. The principle of differential detection is employed which reduces the undesired effects of noise and fluctuations in the source intensity.

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Lavrentjev, Eugene, Anastasia Sergienko, Andrei Shevyrev, and Ekaterina Vasilyeva. "Method for effective monitoring and control of the positioning of the output link of the mechatronic module." E3S Web of Conferences 279 (2021): 01027. http://dx.doi.org/10.1051/e3sconf/202127901027.

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This article is devoted to the problem of linear positioning of the output link of a mechatronic module (MM), made on the basis of a ball screw (ball screw). The analysis of typical schemes for constructing an MM controller using signals from radial position sensors of the ball screw rotor and a discrete indicator of the linear position of the output link in the working stroke section with the possibility of implementing an emergency (emergency) power off of the entire positioning system in the event of the output link extending beyond the working stroke. An optimal technical solution is proposed for constructing a linear positioning sensor of the output link based on combining the functions of the “referent points” indicator and the “limit switch” MM. Тhe cost-effectiveness of the new

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Kim, Gyunam, and Katsuhiro Hirata. "Motion Control of a Two-Degree-of-Freedom Linear Resonant Actuator without a Mechanical Spring." Sensors 20, no. 7 (March 31, 2020): 1954. http://dx.doi.org/10.3390/s20071954.

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This study aims to present a new two-degree-of-freedom (DOF) linear resonant actuator (LRA) and its motion control method without a position sensor. The design method of 2-DOF LRA which resonates with only detent force without a mechanical spring is proposed. Since the information of displacement and direction is required to control 2-DOF LRA, a sensor or an estimator is needed. Therefore, we proposed a position estimator and a motion controller for 2-DOF LRA. This paper proved that reciprocating motion, elliptical motion, and scrolling motion can be controlled without a position sensor. Finite element analysis (FEA) and dynamic simulation results validated the proposed method as well.

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Hariri, Nasir, Hector Gutierrez, John Rakoczy, Richard Howard, and Ivan Bertaska. "Proximity Operations and Three Degree-of-Freedom Maneuvers Using the Smartphone Video Guidance Sensor." Robotics 9, no. 3 (September 10, 2020): 70. http://dx.doi.org/10.3390/robotics9030070.

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This paper presents the first demonstration of NASA’s Smartphone Video Guidance Sensor (SVGS) as real-time position and attitude estimator for proximity and formation maneuvers. An optimal linear quadratic Gaussian controller was used, combining a linear quadratic regulator and a Kalman filter. The system was demonstrated controlling the 3-degree of freedom planar motion of the RINGS ground units (Resonant Inductive Near-field Generation Systems). A state-space model of the system’s 3-DOF motion dynamics was derived, and model parameters extracted using a system identification technique. The system’s motion control performance is experimentally demonstrated in both tracking and formation maneuvers. The results highlight the capabilities and performance of the Smartphone Video Guidance Sensor (SVGS) as a vision-based real-time position and attitude sensor for motion control, formation flight and proximity operations. A leader-follower formation maneuver approach is demonstrated, as well as position hold and path following.

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Shibalkina, Elena, and István Szabó. "Stepper Motor Control System for XY Module for IC Production." Hungarian Agricultural Engineering, no. 39 (2021): 54–64. http://dx.doi.org/10.17676/hae.2021.39.54.

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The presented in the paper control system of the stepper motor of the two-coordinate printing module is developed on the basis of modern elements and allows you to control the stepper motor, providing the required shaft rotation speed and adjusting the number of rotation steps. This system realizes the processing of a moving object in several coordinates simultaneously without kinematic elements that convert rotary motion into linear, which makes it possible to speed up the time and accuracy of the processing tool. A forked optical sensor is used as workpiece position sensors. UART and USB bus are used for communication with the computer.

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Wojtanowski, Jacek, Marcin Jakubaszek, and Marek Zygmunt. "Freeform Mirror Design for Novel Laser Warning Receivers and Laser Angle of Incidence Sensors." Sensors 20, no. 9 (April 30, 2020): 2569. http://dx.doi.org/10.3390/s20092569.

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In this paper, we present a novel configuration of an optical angle-of-incidence (AOI) sensor based on the application of a freeform mirror. The main challenge in designing this mirror was to provide a strictly linear transformation between AOI and the spatial position of the spot created on the linear detector array. Another two goals of this paper were to minimize stray light issues (improve the dynamic range) and create an intermediate focus and lateral shift in the detector position with respect to the plane of incidence. From an optical point of view, the designed mirror can thus be understood as the composition of three components: a high-numerical-aperture (NA) fully achromatic f-theta lens in one cross-section and a perfectly focusing lens, combined with a deviating prism in the second (orthogonal) cross-section. In comparison to the standard “shade” methods, the proposed approach allows a constant angular resolution to be maintained over the entire field of view. The mirror was designed on the basis of fundamental geometrical rules by numerically solving differential problems using an innovative scheme based on the minimization of the specific merit function. The proposed method was practically applied to design a freeform mirror for a 90°/120° field-of-view sensor, showing a satisfactory performance.

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Kuester, Matthew, Nanyaporn Intaratep, and Aurélien Borgoltz. "Laser Displacement Sensors for Wind Tunnel Model Position Measurements." Sensors 18, no. 12 (November 22, 2018): 4085. http://dx.doi.org/10.3390/s18124085.

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Wind tunnel measurements of two-dimensional wing sections, or airfoils, are the building block of aerodynamic predictions for many aerodynamic applications. In these experiments, the forces and pitching moment on the airfoil are measured as a function of the orientation of the airfoil relative to the incoming airflow. Small changes in this angle (called the angle of attack, or α ) can create significant changes in the forces and moments, so accurately measuring the angle of attack is critical in these experiments. This work describes the implementation of laser displacement sensors in a wind tunnel; the sensors measured the distance between the wind tunnel walls and the airfoil, which was then used to calculate the model position. The uncertainty in the measured laser distances, based on the sensor resolution and temperature drift, is comparable to the uncertainty in traditional linear encoder measurements. Distances from multiple sensors showed small, but statistically significant, amounts of model deflection and rotation that would otherwise not have been detected, allowing for an improved angle of attack measurement.

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Sha, Wei, Chao Fang, and Yu Niu. "Successful application of optical bench in Taiji-1 laser interferometer." International Journal of Modern Physics A 36, no. 11n12 (February 22, 2021): 2140001. http://dx.doi.org/10.1142/s0217751x21400017.

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As an important part of laser interferometry system, optical bench is one of the core technologies for the detection of spaceborne gravitational waves. As the first step of the space Taiji program, Taiji-1 provides the measurement accuracy of laser interferometry system better than 100 pm/Hz[Formula: see text](@10 mHz–1 Hz). Taiji-1 is required to be able to track the motion of test mass in inertial sensor. According to the requirements, four interfering optical paths were designed. By adopting an integrated satellite design and selecting the optical and mechanical materials with low linear expansion coefficient, the high stability of optical path was achieved. By using the DOE method, the alignment errors (position/attitude) of four optical paths were all reduced to below 50 [Formula: see text] m/100 [Formula: see text] rad. In the performance test, the accuracy of laser interferometry system was better than 100 pm/Hz[Formula: see text](@10 mHz–1 Hz), and the modulation signal of inertial sensor was successfully detected. The results show that all technical indexes of optical bench have met or exceeded the design requirements.

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Rosle, Wang, and Hirai. "Geometry Optimisation of a Hall-Effect-Based Soft Fingertip for Estimating Orientation of Thin Rectangular Objects." Sensors 19, no. 18 (September 19, 2019): 4056. http://dx.doi.org/10.3390/s19184056.

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Soft tactile sensors have been applied to robotic grippers for assembly. It is a challenging task to obtain contact information and object orientation using tactile sensors during grasping. Currently, the design of Hall-effect-based tactile sensors to perform such tasks is based on trial and error. We present a method of investigating the optimal geometrical design of a cylindrical soft sensor to increase its sensitivity. The finite element model of a soft fingertip was constructed in Abaqus with two design variables, i.e., hollow radius and magnet position. Then, the model was imported into Isight, with the maximisation of magnet displacement as the objective function. We found that the optimal design was at the boundary of the parameter design space. Four fingertips were fabricated with one intuitive, one optimal, and two optional sets of parameters. Experiments were performed, and object orientation was estimated by utilising linear approximation and a machine learning approach. Good agreements were achieved between optimisation and experiments. The results revealed that the estimated average error in object orientation was decreased by the optimised fingertip design. Furthermore, the 3-axis forces could successfully be estimated based on sensor outputs.

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Hsu, Wei-Chun, Tommy Sugiarto, Jun-Wen Chen, and Yi-Jia Lin. "The Design and Application of Simplified Insole-Based Prototypes with Plantar Pressure Measurement for Fast Screening of Flat-Foot." Sensors 18, no. 11 (October 25, 2018): 3617. http://dx.doi.org/10.3390/s18113617.

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This study aimed to find the correlation between conventional Arch Index (AI) measurements and our prototype of a simplified insole-based plantar pressure measurement system and to find out the effective plantar pressure sensor position. Twenty-one subjects participated in this study, which was divided into two groups: 10 subjects with flatfoot and 11 subjects with normal foot. Five force sensitive resistance sensors were used on this prototype using Arduino as the data acquisition device. Two types of trials, namely static and dynamic, were conducted to validate our system against the ink-type AI measurement as a golden standard. The results showed that in the static trial, there was a high linear correlation with the medial arch sensor configuration, while in the dynamic trial, there was a high linear correlation in the medial arch sensor configuration and sensor 5 configuration. This study showed that both static and dynamic tests using the self-developed device could effectively determine most of the flatfoot subjects and suggests that in the future, it can be applied in clinical applications because of its advantages when compared to the expensive-high tech graphic input board and conventional tools, like ink-type based measurements.

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Wakayama, Taku, Takeshi Okuyama, and Mami Tanaka. "Study on detection of lumps in a soft object by using a scanning roller type palpation sensor system." International Journal of Applied Electromagnetics and Mechanics 64, no. 1-4 (December 10, 2020): 745–52. http://dx.doi.org/10.3233/jae-209386.

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In this study, a palpation sensor system is developed to detect a lump in a soft object. The developed sensor system consists of a contact part using a bearing, two linear sliders and a 3-axis load cell. While the roller type contact part is scanned against a soft object, reaction force applied to the contact part is measured. Lumps are detected by measuring fluctuation of the reaction force. In experiments, the sensor system is scanned against the samples. From the results, it is found that the lump with a small diameter embedded at a deep position.

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Ribeiro, Artur Lopes, A. Lopes Ribeiro, Helena G. Ramos, and Tiago J. Rocha. "Defect detection in stainless steel tubes with AMR and GMR sensors using remote field eddy current inspection." ACTA IMEKO 4, no. 2 (June 29, 2015): 62. http://dx.doi.org/10.21014/acta_imeko.v4i2.234.

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The purpose of this paper is to compare the performance of the giant magneto-resistor (GMR) and anisotropic magneto-resistor (AMR) sensors for remote field eddy current testing in stainless steel tubes. Two remote field eddy current probes were built to compare detection and characterization capabilities in standard defects like longitudinal and transverse defects. Both probes include a coil to produce a sinusoidal magnetic field that penetrates the tube wall. Each probe includes a detector with GMR and AMR sensors, where each sensor has four magneto-resistive elements configured in a Wheatstone bridge. Each sensor needs to be biased differently to operate in the high sensitivity linear mode. The description of the measurement system used to detect defects is present in the paper. For the choice of the detector optimal position, numerical simulation and experimental measurements were performed. For comparison of these sensors in defect detection using remote field eddy current testing, the experimental measurements were performed under the same conditions. The results are presented and discussed in the paper.

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Shan, Yuan Yuan, Ming Qin, and Sheng Qi Chen. "The Design and Experiment of a Two-Dimensional Position Sensitive Detecting (PSD) Sensor Based on Avalanche Breakdown." Key Engineering Materials 609-610 (April 2014): 1094–99. http://dx.doi.org/10.4028/www.scientific.net/kem.609-610.1094.

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A two-dimensional position sensitive detecting sensor (PSD) based on avalanche breakdown is introduced in this paper. The structure of the sensor is designed under the assumption that the breakdown of the PN junction in the sensor occurs at the bottom of the PN junction. The breakdown structure and characteristics of the sensor are simulated by Medici software and the doping structure and process conditions are calculated by Tsuprem4 software. By using COMSOL Multiphysics, we obtained current allocation of the straight and right angle type electrodes, which is corresponding to the optimal structure. In simulation, the root mean square error of the rectangular-shaped electrode and the straight line-shaped electrode are 0.198, 0.145 respectively. Experiment results show that in the 50% photosensitive area with the center as the origin, the rectangular-shaped electrode error is much smaller than a straight line-shaped electrode and fits in to linear relationship better. But the error of the angle the boundary of the electrode is significantly worse than the line-shaped electrode.

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Hariri, Nasir, Hector Gutierrez, John Rakoczy, Richard Howard, and Ivan Bertaska. "Performance Characterization of the Smartphone Video Guidance Sensor as Vision-Based Positioning System." Sensors 20, no. 18 (September 16, 2020): 5299. http://dx.doi.org/10.3390/s20185299.

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The Smartphone Video Guidance Sensor (SVGS) is a vision-based sensor that computes the six-state position and orientation vector of a target relative to a coordinate system attached to a smartphone. This paper presents accuracy-characterization measurements of the Smartphone Video Guidance Sensor (SVGS) to assess its performance as a position and attitude estimator, evaluating its accuracy in linear and angular motion for different velocities and various types of targets based on the mean and standard deviation errors between SVGS estimates and known motion profiles, in both linear and angular motions. The study also examines the effects of target velocity and sampling rate on the overall performance of SVGS and provides an overall assessment of SVGS’ performance as a position/attitude estimator. While the error metrics are dependent on range and camera resolution, the results of this paper can be scaled to other operational conditions by scaling the blob size in pixels (the light markers identified in the images) relative to the total resolution (number of pixels) of the image. The error statistics of SVGS enable its incorporation (by synthesis of a Kalman estimator) in advanced motion-control systems for navigation and guidance.

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Beadle, James, C. James Taylor, Kirsti Ashworth, and David Cheneler. "Plant Leaf Position Estimation with Computer Vision." Sensors 20, no. 20 (October 20, 2020): 5933. http://dx.doi.org/10.3390/s20205933.

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Autonomous analysis of plants, such as for phenotyping and health monitoring etc., often requires the reliable identification and localization of single leaves, a task complicated by their complex and variable shape. Robotic sensor platforms commonly use depth sensors that rely on either infrared light or ultrasound, in addition to imaging. However, infrared methods have the disadvantage of being affected by the presence of ambient light, and ultrasound methods generally have too wide a field of view, making them ineffective for measuring complex and intricate structures. Alternatives may include stereoscopic or structured light scanners, but these can be costly and overly complex to implement. This article presents a fully computer-vision based solution capable of estimating the three-dimensional location of all leaves of a subject plant with the use of a single digital camera autonomously positioned by a three-axis linear robot. A custom trained neural network was used to classify leaves captured in multiple images taken of a subject plant. Parallax calculations were applied to predict leaf depth, and from this, the three-dimensional position. This article demonstrates proof of concept of the method, and initial tests with positioned leaves suggest an expected error of 20 mm. Future modifications are identified to further improve accuracy and utility across different plant canopies.

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Yim, Woosoon, Jichun Zuang, and Sahjendra Singh. "Experimental dual-mode control of a flexible robotic arm." Robotica 10, no. 2 (March 1992): 135–45. http://dx.doi.org/10.1017/s0263574700007554.

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SUMMARYThis paper focuses on the implementation of a dual-mode controller for the maneuver of a single link flexible robotic arm. The joint angle trajectory tracking is accomplished by a proportional and derivative PD and a feedforward controller. Based on the pole placement technique, a linear stabilizer is designed for elastic mode stabilization. The stabilizer is switched on when the trajectory reaches the vicinity of the terminal state, and the effect of switching time on arm vibration is investigated. An optical deflection sensor is used for on-line measurements of elastic deflections, and also used for the prediction of the static deflection of the arm in the target position. The robustness of the linear stabilizer at varying pay loads is presented.

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Kotus, Józef, and Grzegorz Szwoch. "Estimation of Average Speed of Road Vehicles by Sound Intensity Analysis." Sensors 21, no. 16 (August 7, 2021): 5337. http://dx.doi.org/10.3390/s21165337.

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Constant monitoring of road traffic is important part of modern smart city systems. The proposed method estimates average speed of road vehicles in the observation period, using a passive acoustic vector sensor. Speed estimation based on sound intensity analysis is a novel approach to the described problem. Sound intensity in two orthogonal axes is measured with a sensor placed alongside the road. Position of the apparent sound source when a vehicle passes by the sensor is estimated by means of sound intensity analysis in three frequency bands: 1 kHz, 2 kHz and 4 kHz. The position signals calculated for each vehicle are averaged in the analysis time frames, and the average speed estimate is calculated using a linear regression. The proposed method was validated in two experiments, one with controlled vehicle speed and another with real, unrestricted traffic. The calculated speed estimates were compared with the reference lidar and radar sensors. Average estimation error from all experiment was 1.4% and the maximum error was 3.2%. The results confirm that the proposed method allow for estimation of time-averaged road traffic speed with accuracy sufficient for gathering traffic statistics, e.g., in a smart city monitoring station.

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Kroh, Christoph, Roland Wuchrer, Margarita Günther, Thomas Härtling, and Gerald Gerlach. "Evaluation of the pH-sensitive swelling of a hydrogel by means of a plasmonic sensor substrate." Journal of Sensors and Sensor Systems 7, no. 1 (February 6, 2018): 51–55. http://dx.doi.org/10.5194/jsss-7-51-2018.

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Abstract. The inline monitoring of parameters in aqueous liquids is facing an increasing demand in many different application areas. Hydrogels with pH-induced swelling and deswelling behavior offer a means to measure pH in such liquids. Here we investigate the optical interrogation of a pH-sensitive hydrogel which can be applied in the physiological pH range. For this, a nanostructured gold substrate supporting surface plasmon oscillations is coated with a HPMA/DMAEMA/TEGDMA/EG hydrogel. The gel swells in the pH range under investigation (here 4.5 to 6.5), and the resulting refractive index changes subsequently lead to a spectral shift of the plasmon resonance of the gold nanostructure. The spectral resonance position is determined from optical transmittance spectra of the sensor substrates, and the initial results for our hydrogel reported here indicate a nearly linear dependence between the swelling state and the plasmon resonance wavelength.

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Zhang, Fan, Hengjun Zhu, Kan Bian, Pengcheng Liu, and Jianhui Zhang. "Absolute Position Coding Method for Angular Sensor—Single-Track Gray Codes." Sensors 18, no. 8 (August 19, 2018): 2728. http://dx.doi.org/10.3390/s18082728.

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Single-track Gray codes (STGCs) is a type of absolute position coding method for novel angular sensors, because it has single-track property over traditional Gray codes and mono-difference over linear feedback shift register codes. However, given that the coding theory of STGCs is incomplete, STGC construction is still a challenging task even though it has been defined for more than 20 years. Published coding theories and results on STGCs are about two types of STGC, namely, necklace and self-dual necklace ordering, which are collectively called as k-spaced head STGCs. To find a new code, three constraints on generating sequences are proposed to accelerate the searching algorithm, and the complete searching result of length-6 STGCs is initially obtained. Among the entire 132 length-6 STGCs, two novel types of STGCs with non-k-spaced heads are found, and the basic structures of these codes with the general length n are proposed and defined as twin-necklace and triplet-necklace ordering STGCs. Furthermore, d-plet-necklace ordering STGC, which unifies all the known STGCs by changing the value of d, is also defined. Finally, a single-track absolute encoder prototype is designed to prove that STGCs are as convenient as the traditional position coding methods.

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Zhang, Youzhi, Jinhua Ye, Haomiao Wang, Shuheng Huang, and Haibin Wu. "A Flexible Tactile Sensor with Irregular Planar Shape Based on Uniform Electric Field." Sensors 18, no. 12 (December 15, 2018): 4445. http://dx.doi.org/10.3390/s18124445.

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Tactility is an essential perception for intelligent equipment to acquire external information. It can improve safety and performance during human-machine interactions. Based on the uniqueness theorem of the electrostatic field, a novel flexible film tactile sensor that can detect contact position and be made into any plane shape is proposed in this paper. The tactile sensor included an indium tin oxide (ITO) film, which was uniformly coated on the polyethylene terephthalate (PET) substrate. A specially designed strong conductive line was arranged along the edge of the flexible ITO film, which has weak conductivity. A bias excitation was applied to both ends of the strong conductive line. Through the control of the shape of the strong conductive line, a uniform electric field can be constructed in the whole weak conductive plane. According to the linear relationship between position and potential in the uniform electric field, the coordinate of the contact position can be determined by obtaining the potential of the contact point in the weak conducting plane. The sensor uses a three-layer structure, including an upper conductive layer, an intermediate isolation layer, and a lower conductive layer. A tactile sensor sample was fabricated. The experiment results showed that the principle of the tactile sensor used for the contact position detection is feasible and has certain precision of position detection. The sensor has good flexibility, and can be made into any plane shape, and has only four wires. It is capable of covering large areas of robot arms, and provides safety solutions for most robots.

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Zhao, Ping, Wen Zhen Zhao, and Zhen Yun Duan. "A Calibration Method for High Precision Vision Measurement System." Applied Mechanics and Materials 543-547 (March 2014): 1005–8. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.1005.

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In order to realize precision measurement for the computer vision measurement system, a system comprehensive calibration method based on straight line imaging characteristics is proposed. The method uses parallel straight line edges of general 00 level gauge groups to comprehensively calibrate the measurement system. It establishes the calibration function that describes the corresponding relationship between the imaging point location and space point position, and then determines the coefficient of the calibration function according to the linear characteristic of gauge block measurement surface edges imaging. This method is simple to operate and is easy to realize and has good versatility. It can comprehensively correct all kinds of system errors such as the optical distortion, the perspective error, the sensor position error and location error of edge detection algorithm. Repeated measurement experiments for the gauges show that the precision of the measurement system can reach by means of this calibration method.

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Huysmans, Dorien, Pascal Borzée, Dries Testelmans, Bertien Buyse, Tim Willemen, Sabine Van Huffel, and Carolina Varon. "Evaluation of a Commercial Ballistocardiography Sensor for Sleep Apnea Screening and Sleep Monitoring." Sensors 19, no. 9 (May 8, 2019): 2133. http://dx.doi.org/10.3390/s19092133.

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There exists a technological momentum towards the development of unobtrusive, simple, and reliable systems for long-term sleep monitoring. An off-the-shelf commercial pressure sensor meeting these requirements is the Emfit QS. First, the potential for sleep apnea screening was investigated by revealing clusters of contaminated and clean segments. A relationship between the irregularity of the data and the sleep apnea severity class was observed, which was valuable for screening (sensitivity 0.72, specificity 0.70), although the linear relation was limited ( R 2 of 0.16). Secondly, the study explored the suitability of this commercial sensor to be merged with gold standard polysomnography data for future sleep monitoring. As polysomnography (PSG) and Emfit signals originate from different types of sensor modalities, they cannot be regarded as strictly coupled. Therefore, an automated synchronization procedure based on artefact patterns was developed. Additionally, the optimal position of the Emfit for capturing respiratory and cardiac information similar to the PSG was identified, resulting in a position as close as possible to the thorax. The proposed approach demonstrated the potential for unobtrusive screening of sleep apnea patients at home. Furthermore, the synchronization framework enabled supervised analysis of the commercial Emfit sensor for future sleep monitoring, which can be extended to other multi-modal systems that record movements during sleep.

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Kang, SeYoung, TaeHyun Kim, and WonZoo Chung. "Hybrid RSS/AOA Localization using Approximated Weighted Least Square in Wireless Sensor Networks." Sensors 20, no. 4 (February 20, 2020): 1159. http://dx.doi.org/10.3390/s20041159.

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We present a target localization method using an approximated error covariance matrix based weighted least squares (WLS) solution, which integrates received signal strength (RSS) and angle of arrival (AOA) data for wireless sensor networks. We approximated linear WLS errors via second-order Taylor approximation, and further approximated the error covariance matrix using a least-squares solution and the variance in measurement noise over the sensor nodes. The algorithm does not require any prior knowledge of the true target position or noise variance. Simulations validated the superior performance of our new method.

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Molina-Cantero, Alberto J., Juan A. Castro-García, Fernando Gómez-Bravo, Rafael López-Ahumada, Raúl Jiménez-Naharro, and Santiago Berrazueta-Alvarado. "Controlling a Mouse Pointer with a Single-Channel EEG Sensor." Sensors 21, no. 16 (August 14, 2021): 5481. http://dx.doi.org/10.3390/s21165481.

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(1) Goals: The purpose of this study was to analyze the feasibility of using the information obtained from a one-channel electro-encephalography (EEG) signal to control a mouse pointer. We used a low-cost headset, with one dry sensor placed at the FP1 position, to steer a mouse pointer and make selections through a combination of the user’s attention level with the detection of voluntary blinks. There are two types of cursor movements: spinning and linear displacement. A sequence of blinks allows for switching between these movement types, while the attention level modulates the cursor’s speed. The influence of the attention level on performance was studied. Additionally, Fitts’ model and the evolution of the emotional states of participants, among other trajectory indicators, were analyzed. (2) Methods: Twenty participants distributed into two groups (Attention and No-Attention) performed three runs, on different days, in which 40 targets had to be reached and selected. Target positions and distances from the cursor’s initial position were chosen, providing eight different indices of difficulty (IDs). A self-assessment manikin (SAM) test and a final survey provided information about the system’s usability and the emotions of participants during the experiment. (3) Results: The performance was similar to some brain–computer interface (BCI) solutions found in the literature, with an averaged information transfer rate (ITR) of 7 bits/min. Concerning the cursor navigation, some trajectory indicators showed our proposed approach to be as good as common pointing devices, such as joysticks, trackballs, and so on. Only one of the 20 participants reported difficulty in managing the cursor and, according to the tests, most of them assessed the experience positively. Movement times and hit rates were significantly better for participants belonging to the attention group. (4) Conclusions: The proposed approach is a feasible low-cost solution to manage a mouse pointer.

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Sands, Timothy, Kevin Bollino, Isaac Kaminer, and Anthony Healey. "Autonomous Minimum Safe Distance Maintenance from Submersed Obstacles in Ocean Currents." Journal of Marine Science and Engineering 6, no. 3 (August 22, 2018): 98. http://dx.doi.org/10.3390/jmse6030098.

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A considerable volume of research has recently blossomed in the literature on autonomous underwater vehicles accepting recent developments in mathematical modeling and system identification; pitch control; information filtering and active sensing, including inductive sensors of ELF emissions and also optical sensor arrays for position, velocity, and orientation detection; grid navigation algorithms; and dynamic obstacle avoidance, amongst others. In light of these modern developments, this article develops and compares integrative guidance, navigation, and control methodologies for the Naval Postgraduate School’s Phoenix submerged autonomous vehicle, where these methods are assumed available. The measure of merit reveals how well each of several proposed methodologies cope with known and unknown disturbances, such as currents that can be constant or harmonic, while maintaining a safe passage distance from underwater obstacles, in this case submerged mines. Classical pole-placement designs establish nominal baseline behaviors and are subsequently compared to performance of designs that are optimized to satisfy linear quadratic cost functions in regulators as well as linear-quadratic Gaussian designs. Feed-forward architectures and integral control designs are also evaluated. A noteworthy contribution is a very simple method to mimic optimal results with a “rule of thumb” criteria based on the design’s time constant. Since the rule-of-thumb method uses the assumed system model for computation of the control, it is particularly generic. Cited references each contain methods for online system parameter identification (with a motivation of use in the finding the control signal), permitting the rule of thumb’s generic applicability, since it is expressed in terms of the system parameters. This proposed method permits control design at sea where significant computation abilities are not available. Very simple waypoint guidance is also introduced to guide a vehicle along a preplanned path through a field of obstacles placed at random locations. The linear-quadratic Gaussian design proves best when augmented with integral control, and works well with reduced-order equations, while the “rule of thumb” design is seen to closely mimic the optimal performance. Feed-forward augmentation proves particularly efficient at rejecting constant disturbances, while augmentation with integral control is necessary to counter periodic disturbances, where the augmentations are also optimized in the linear-quadratic Gaussian procedures, yet can be closely mimicked by the proposed “rule of thumb” technique.

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Garcia-Huerta, Raul A., Luis E. González-Jiménez, and Ivan E. Villalon-Turrubiates. "Sensor Fusion Algorithm Using a Model-Based Kalman Filter for the Position and Attitude Estimation of Precision Aerial Delivery Systems." Sensors 20, no. 18 (September 13, 2020): 5227. http://dx.doi.org/10.3390/s20185227.

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In this research, we focus on the use of Unmanned Aerial Vehicles (UAVs) for the delivery of payloads and navigation towards safe-landing zones, specifically on the modeling of flight dynamics of lightweight vehicles denoted Precision Aerial Delivery Systems (PADSs). While a wide range of nonlinear models has been developed and tested on high-end applications considering various degrees of freedom (DOF), linear models suitable for low-cost applications have not been explored thoroughly. In this study, we propose and compare two linear models, a linearized version of a 6-DOF model specifically developed for micro-lightweight systems, and an alternative model based on a double integrator. Both linear models are implemented with a sensor fusion algorithm using a Kalman filter to estimate the position and attitude of PADSs, and their performance is compared to a nonlinear 6-DOF model. Simulation results demonstrate that both models, when incorporated into a Kalman filter estimation scheme, can determine the flight dynamics of PADSs during smooth flights. While it is validated that the double integrator model can adequately operate under the proposed estimation scheme for up to small acceleration changes, the linearized model proves to be capable of reproducing the nonlinear model characteristics even during moderately steep turns.

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Ding, Wen-Hua, Xiao-Peng Xie, PAN-Feng Zhang, and Lei Han. "A Novel Tension Control System of Square Lithium Battery Laminated Machine." Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) 13, no. 1 (February 20, 2020): 69–79. http://dx.doi.org/10.2174/2352096512666190411112015.

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Background: To the problem that the traditional square laminated machine with passive unwinding control strategy makes the tape speed periodical changing in reciprocating motion and not achieve a good tension control, a novel unwinding system and control algorithm are presented to improve the efficiency and quality of such equipment. Methods: Compared with the traditional passive unwinding control system, the novel tension control system adds an active compliance mechanism. After obtaining the motion relationship between the compliance device and the laminated motion platform through building the complex system mathematical model, the laminated machine tension control is equivalent to a spatial trajectory tracking control, and multi-axis synchronous coordinated control algorithm is used to control their relative motions, and a cross-coupling control in multi-axis coordinated motion is presented to decrease the synchronous error of the two linear servo motors, which are the compliance device driving motor and the laminated motion platform driving one. Without tension sensor, however, good tension control is obtained only by position tracking control. Results: Based on the proposed approaches and novel unwinding mechanism, the tension control was examined on an experimental square lithium battery laminated machine and results of the experiments performed with the experimental setup demonstrated the effectiveness of the proposed approach. Conclusion: Without a tension sensor, good tension control is obtained only by position tracking control in the novel unwinding system, and the production quality and efficiency of the lithium battery laminated machine are improved.

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Journal articles on the topic 'Linear optical position sensor'

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