Angular Displacement Sensor Research Articles

An Angular Displacement Microwave Sensor with 360° Dynamic Range Using Multi-Mode Resonator

This article presents the application of a novel multi-mode resonator (MMR) named rotational cross-shaped resonator (RCSR) to the design of a planar angular displacement microwave sensor. This MMR developed by four connected stubs with short and open terminations. Since the generated transmission zeros of the RCSR vary linearly with changes in stub lengths, the RCSR structure that makes use of this principle is proposed for implementing angular displacement sensing. The sensor consists of an open-ended stub of RCSR housed by a circular rotor and the rest of the RCSR on the stator. As the position of the stub of RCSR is modified by rotating the rotor, the generated transmission zeros will drift accordingly. Based on the multiple zeros, the proposed angular displacement sensor can provide distinctive direction of rotation detection in addition to dual-sensing measures output. A sensor prototype at 1.95 GHz is designed and experimentally characterized, which reports that both the angle and direction of rotation detections can be realized. The average frequency sensitivity in terms of the variation of a single transmission zero is 1.22 MHz/degree for the dynamic range from −180° to 180°, as well as the average bandwidth sensitivity in terms of the frequency difference between two zeros is 2.61 MHz/degree for the dynamic range from 0° to 180°.

Optimal Design of Angular Displacement Sensor with Shared Magnetic Field Based on the Magnetic Equivalent Loop Method.

Angular displacement sensor with shared magnetic field has strong environmental adaptability and high measurement accuracy. However, its 3-D structure is multi-pole double-layer structure, using time stepping finite element method (TSFEM) to optimize the structure is time-consuming and uneconomical. Therefore, a magnetic equivalent loop method (MELM) is proposed to simplify the optimal design of sensors. By reasonably setting the node position, the mechanical structure parameters, winding coefficients and input voltage of the sensor are integrated into a mathematical model to calculate of the induced voltage. The calculation results are compared with the simulation results, and a sensor prototype is made to test the optimized effect of the MELM.

A Self-Calibration Method for Angular Displacement Sensor Working in Harsh Environments

This paper presents a new self-calibration method for angular displacement sensor, named coaxial sensors relative rotation (CSRR) method, which is suitable for sensors working in harsh environments. With a few slight modifications to the machine, CSRR method can also self-calibrate sensors on their application axes. This method works with two sensors. One sensor provides a benchmark and the other provides relative rotation against the benchmark, then each sensor can be self-calibrated by measuring the synchronized angular displacements of sensors and calculating the relative rotation angles. Experimental results indicate that this method is insensitive to relative rotation error of the two coaxial sensors, and it is also insensitive to sampling uniformity in particular situation. In that particular situation, the calibration accuracy can be better than ±2” when the system error of sensor is about ±650”. Compared with equal division averaged method, CSRR method mostly requires fewer sensors to get the same calibration accuracy; and compared with time-measurement dynamic reversal method, CSRR method performs better on the axis supported by rolling bearing. What is more, we propose an evaluation indicator $\vert Y_{\boldsymbol {\Omega }}\vert $ to evaluate the effective range of the CSRR method, and the $\vert Y_{\boldsymbol {\Omega }}\vert $ makes it easier for others to determine whether this method is suitable for their applications.

Detecting the Rotation Direction in Contactless Angular Velocity Sensors Implemented With Rotors Loaded With Multiple Chains of Resonators

In this paper, a strategy to detect the rotation direction in angular displacement and velocity sensors based on rotors loaded with circular chains of split ring resonators (SRRs) is presented. The rotor (made of a dielectric material) is loaded with two concentric SRR chains for measuring the angular velocity (angular velocity chains) and with one additional (also concentric) non-periodic resonator chain for detecting the direction of motion (rotation direction chain). The stator is a CPW transmission line placed below the rotor chains, in close proximity to them, with the line axis oriented in the radial direction of the rotor. A novel relevant contribution of this paper concerns the detailed study of the rotation direction sensor, from which we have concluded that the design must be completely different than the one of the angular velocity sensor (single SRR on the rotor). By this means, the transmission coefficient of the CPW is modulated by rotor motion (through electromagnetic coupling), as the SRRs of the different chains cross the CPW axis. By injecting a double-tuned signal to the line (with carrier frequencies tuned to the SRR resonance frequencies of both chains), two superposed amplitude modulated (AM) signals at the output port of the CPW arise. From the envelope of both AM signals, discriminated by means of a designed diplexer, the angular velocity and the rotation direction can be determined.

An Angular Displacement Sensor With a Curved Two-Metal-Layer CPW Loaded by an EBG Structure

This paper presents a microwave angular displacement sensor that consists of a curved two-metal-layer coplanar waveguide (TML CPW) loaded by an electromagnetic bandgap structure (two semi-cylindrical periodic air-gap structures of dielectrics, allocated at the top and bottom of the curved TML CPW). Rotating one of the dielectrics against the other one, produces a variation in the depth of the stopband at the central frequency. The magnitude change is proportional to the angle of the rotation. The curved TML CPW line with the length of 140 mm is fabricated on a $254~\mu \text{m}$ thick RO3010 Rogers substrate ( $\varepsilon _{r} = 10.2$ and $\tan \delta = 0.0022$ ), which is arched in a semi-cylindrical shape with a radius of 50 mm. The periodic air-gap structures, in order to create the electromagnetic bandgap, are manufactured by laser cutting of an optically transparent polycarbonate ( $\varepsilon _{r} = 2.8$ and $\tan \delta =0.01$ ) in semi-cylindrical shapes. The analysis, finite element method simulation, realization, and measurements have been performed for the sensor with 15 unit cells. An average sensitivity and a dynamic range of about 3 dB/deg and 5° degrees, respectively, have been obtained at 10.2 GHz. The fixed operating frequency and the wide bandwidth of the sensor (>1 GHz) will simplify the design and fabrication of the data readout circuit. The impact of the structure curvature on the sensor response is also investigated as an important practical issue.

Application of Split Ring Resonator (SRR) Loaded Transmission Lines to the Design of Angular Displacement and Velocity Sensors for Space Applications

The accurate measurement of the angular displacement and velocity of reaction wheels is necessary for attitude (orientation) control in space vehicles (satellites). In this paper, microwave, contactless, and low-cost (as compared to optical encoders) sensors useful for that purpose are analyzed in detail. The sensor consists of a rotor and a stator. The rotor is a disk (or a circular crown) of dielectric material, where one or several arrays of equidistant single-loop split ring resonators (SRRs) are etched along its edge, forming circular chains of hundreds of SRRs. The stator is a coplanar waveguide (CPW) also loaded with pairs of single-loop SRRs (etched in the back substrate side), with the centers located in the slot region. The sensing principle is based on the amplitude modulation of a harmonic (single-tone continuous wave) feeding signal, achieved when the chains of the rotor are displaced over the SRR pairs of the stator. Both sensor elements (rotor and stator) must be parallel oriented, with the SRR pairs of the CPW in close proximity to the SRR chains of the rotor (and rotated 180°), in order to favor their coupling. By this means, the transmission coefficient of the CPW is varied by the circular motion of the rotor, and significant amplitude modulation of the feeding signal is achieved. From the envelope function, the angular velocity can be accurately determined. With the proposed sensors, instantaneous and practically unlimited rotation speeds can be measured.

Sensor fault-tolerant control for gear-shifting engaging process of automated manual transmission

Abstract Angular displacement sensor on the actuator of automated manual transmission (AMT) is sensitive to fault, and the sensor fault will disturb its normal control, which affects the entire gear-shifting process of AMT and results in awful riding comfort. In order to solve this problem, this paper proposes a method of fault-tolerant control for AMT gear-shifting engaging process. By using the measured current of actuator motor and angular displacement of actuator, the gear-shifting engaging load torque table is built and updated before the occurrence of the sensor fault. Meanwhile, residual between estimated and measured angular displacements is used to detect the sensor fault. Once the residual exceeds a determined fault threshold, the sensor fault is detected. Then, switch control is triggered, and the current observer and load torque table estimates an actual gear-shifting position to replace the measured one to continue controlling the gear-shifting process. Numerical and experiment tests are carried out to evaluate the reliability and feasibility of proposed methods, and the results show that the performance of estimation and control is satisfactory.

Image jitter detection and compensation using a high-frequency angular displacement method for Yaogan-26 remote sensing satellite

Satellite platform jitter is an important factor restricting the imaging quality of high-resolution (HR) optical satellite images. To address the critical issue of compensation for attitude jitter in HR images, this paper proposes a steady-state reimaging model using high-frequency angular displacement data to detect and compensate for the attitude jitter of HR images. The bidirectional Kalman filter and overall weighted smoothing method helps realizing information fusion of star sensor and angular displacement sensor and obtaining the high-frequency attitude for image jitter detection. Then, the steady reimaging model is used to correct the distorted image with geolocation consistency based on a rigorous geometric model. The Yaogan-26 remote sensing satellite’s distorted panchromatic images of airports, targets and calibration fields affected by platform jitter were used to validate the effectiveness and accuracy of the proposed method. The compensation results show that the proposed method can effectively improve the relative geometric quality of images affected by platform jitter, with the images’ jitter distortion being clearly eliminated. Compared to the conventional compensation method that bundle adjustment with GCPs, the absolute geometric accuracy can also be improved.

Simulation Analysis and Experiment of Variable-Displacement Asymmetric Axial Piston Pump

The variable displacement pump control system has greater energy-saving advantages and application prospects than the valve control system. However, the variable displacement pump control of differential cylinder is not concurrent with the existing technologies. The asymmetric pump-controlled cylinder is, therefore, used to balance the unequal volume flow through a single rod cylinder in closed-circuit system. This is considered to be an effective method. Nevertheless, the asymmetric axial piston pump (AAPP) is a constant displacement pump. In this study, variable-displacement asymmetric axial piston pump (VAPP) is investigated according to the same principle used in investigating AAPP. This study, therefore, aims at investigating the characteristics of VAPP. The variable-displacement output of VAPP is implemented by controlling the swash plate angle with angle feedback control circuit, which is composed of a servo proportional valve and an angular displacement sensor. The angular displacement sensor is connected to the swash plate. The simulation model of VAPP, which is set up through the ITI-SimulationX simulation platform, is used to predict VAPP’s characteristics. The purpose of implementing the experiment is to verify the theoretical results. Both the simulation and the experiment results demonstrated that the swash plate angle is controlled by a variable mechanism; when the swash plate angle increases, the flow of Port B and Port T increases while the response speed of Port B and Port T also accelerates. When the swash plate angle is constant, the flow of Port B and Port T increases along with the increase of pump speed, although the pressure-response speed of Port B is faster than that of Port T. Consequently, the flow pulsation of Port B and Port T tends to decrease gradually along with the increase of pump speed. When the pressure loaded on Port B equals to that of Port T, the flow ripple cycle of Port B is longer than that of Port T, whereas the peak flow of Port B is higher than that of Port T. Since the flow ripple of Port T is bigger than that of Port B, Port T should be connected to the low pressure sides or the oil tank so that it does not affect VAPP’s performance. Further, to avoid the backflow of VAPP from Port T to Port B, Port T cannot be loaded alone, and the loading pressure of Port T also cannot exceed that of Port B.

基于平面线圈的高分辨力时栅角位移传感器

基于平面线圈的高分辨力时栅角位移传感器

Simulation and experimental studies of a double-fiber angular displacement sensor

A novel optical fiber angular displacement sensor is reported in this study. It gets the rotating angle of an object by means of the intensity modulation of a reflected light. The sensor probe, which is composed of an emitting fiber and a receiving fiber that are aligned along the vertical direction closely, is fixed directly on the rotating object. The measurements for axial displacement and angular displacement were operated separately. In particular, measurements for angular displacement were performed when the reflector is placed at different distances from the sensor probe separately. There is an excellent linearity between the angular displacement and the sensor output power. The results indicate that the larger the distance between the sensor probe and the reflector, the higher sensitivity the angular displacement sensor has. A theoretical model of the sensor is also developed and the simulate computation demonstrates that the theoretical results are in accordance with the experimental ones. The linear sensing range is ±7.2°, and the maximum sensitivity is 13.71%/deg. Furthermore, the hysteresis and the reproducibility of the measurement of the sensor are investigated. The designed sensor provides a kind of simple and effective method for measuring the angular displacement of a shaft system in practice due to its small size, light weight, good linearity and reproducibility.

Development of a combined magnetic encoder

Purpose As a type of angular displacement sensor, the Hall-effect magnetic encoder incorporates many advantages. While compared with the photoelectric encoder, the magnetic encoder nevertheless has lower precision and lower resolution. So, the purpose of this essay is to find a way to increase the precision and resolution of the magnetic encoder. Design/methodology/approach By combining a single-pole magnetic encoder and a multi-pole AlNiCo magnet, the precision and resolution of this combined magnetic encoder are increased without increasing its volume or complicating its structure. A special algorithm system is developed to ensure faithful encoding and decoding. Findings Tests show that the combined magnetic encoder, with a diameter of 67.12 mm (including shaft) and thickness of 6.9 mm, has a precision of ±6′, compared with a 15-bit photoelectric encoder and a static resolution of ±0.6′. Originality/value This new kind of magnetic encoder could be used in specialized fields which need high-precision servo-control systems that are small, have ultra-low-speed and high-speed ratios and are non-oil-polluting or shock-resistant.

A Differential Reflective Intensity Optical Fiber Angular Displacement Sensor.

In this paper, a novel differential reflective intensity optical fiber angular displacement sensor was proposed. This sensor can directly measure the angular and axial linear displacement of a flat surface. The structure of the sensor probe is simple and its basic principle was first analyzed according to the intensity modulation mechanisms. Secondly, in order to trim the dark output voltage to zero, the photoelectric conversion circuit was developed to adjust the signals. Then, the sensor model including the photoelectric conversion circuit has been established, and the influence of design parameters on the sensor output characteristic has been simulated. Finally, the design parameters of the sensor structure were obtained based on the simulation results; and an experimental test system was built for the sensor calibration. Experimental results show that the linear angular range and the sensitivity of the sensor were 74.4 and 0.051 V/°, respectively. Its change rules confirm the operating principle of the sensor well.

Simulation and Implementation of Angular Displacement Measurement System for Antenna Positioning

Objective: To design angular displacement measurement system. Methods: System is simulated by using free and open source Scilab. The overall minimum, real time system is designed around an 8-bit cost effective, MCS51 microcontroller 89C2051. A high precision wire wound potentiometer serves as an angular displacement sensor. The digitized sensor output form ADC0804, after processing is displayed on LCD. The system is minimized by connecting ADC in free running mode and LCD in 4-bit mode. Findings: The system is tested for measurement of an angular displacement in the range of 0-180°. The results of simulation and the experimental measurements are in good agreement. Application: The system is suitable for angular displacement measurement for antenna positioning.

Sensor fault diagnosis and processing for a two-speed AMT for pure electric vehicles

In shifting process for the two-speed AMT (automated manual transmission) in this paper, the position of synchronizer sleeve is reflected by output signal of an angular displacement sensor, therefore, the normal operation of the sensor is the key to complete shifting accurately and reliably. To improve the fault-tolerant ability of two-speed AMT for electric vehicles, the operation principle of the shifting actuator and the shifting process of the two-speed AMT are analyzed. A signal revised strategy and a vehicle failure mode are proposed for the sensor signal drift and sensor fault respectively. A test bed based on dSPACE real time simulation was set up for the two-speed AMT and the sensor fault diagnosis and processing strategy was verified by experiment. The experiment results indicate that the proposed strategy can be achieved under the simulation of sensor signal drift and sensor fault, improving the reliability of the AMT.

Real-time monitoring instrument designed for the deformation and sliding period of colluvial landslides

A real-time monitoring instrument for colluvial landslides that can capture horizontal displacement during the deformation period of the slope, deep dislocation displacement, accurate depth of the slip surface, and sliding direction during the initial sliding period has been developed. The horizontal displacement monitoring system is a monitoring apparatus assembled in an array based on the MEMS (Micro-Electro-Mechanical System). Horizontal displacement is obtained by integration of the X- and Y-direction angles along the drilling direction, and the sliding direction is simultaneously measured via vector composition of the X- and Y-direction angles obtained from the MEMS sensor. Deep dislocation displacement is calculated based on the relative displacement between the base point embedded in the bedrock and measuring point above the sliding surface, and measurement of relative displacement is executed by an angular displacement sensor fixed on top of the inclinometer tube. The accurate depth measurement of the slip surface is transferred to the judgment about the on-off state of the signal wire. Based on the long-term monitoring of the Yu Jiaba landslide at the Three George dams, an open-pit mine in Inner Mongolia province, and an Anshan open-pit mine, the results reveal that the reliability of the instrument is very high. High accuracy, ability to capture the entire landslide process, large deformation monitoring, autonomous data collection, and reusable characteristics could be implemented.

Angular Displacement Sensor Based on Coplanar Waveguide (CPWs) Loaded with S-Shaped Golden Spiral-Tapered Split Ring Resonators (SGS-SRRs)

An angular displacement sensor based on coplanar waveguides (CPWs) loaded with s-shaped golden spiral-tapered split ring resonators (SGS-SRRs) is proposed in this paper. The proposed device is composed of a CPW and a SGS-SRR which was designed based on the golden ratio number and etching on double copper layer of PCB. The transmission coefficient (S21), linearity and sensitivity of the sensor were simulated and analyzed using electromagnetic models. The results show that the sensor was able to sense the rotation angle. It has a wide dynamic range, high linearity, higher sensitivity and lower cost, which is particularly suitable for use as a sensor and transducer technology in the future.

An Inductive Angular Displacement Sensor Based on Planar Coil and Contrate Rotor

This paper introduces a noncontact, low-cost, and reliable inductive sensor for angular displacement measurement. It is suitable to work in harsh industrial environments. The sensor has simple structure consisting of three key parts: a ferromagnetic stator, which is a pure plane; a ferromagnetic rotor, which has face slots; and four layers of planar copper coils, including primary and secondary coils. Primary coils are supplied with two orthogonal 4000-Hz ac, and secondary coils output a signal whose phase is proportional to angular displacement. Primary coils are designed with sinusoidal shape, so that magnetic field between the stator and rotor has approximately sinusoidal distribution, and finally linearity between the phase variation of output signal and angular displacement is well helped by this design. The structure and working principles of the sensor are explained in detail. Moreover, a sensor model was simulated to verify the feasibility of the sensor working principles and a sensor prototype was designed for actual experiment. At last actual experiment results are given and analyzed, showing that the sensor prototype has achieved accuracy better than ±12 arcsec in the range of 0°-360°, and this kind of sensor may have a better performance by improving the layout of primary coils and front-end signal-process circuit.

에어셀을 이용한 손목 재활훈련 장치

Abstract: In this paper, we propose a wrist rehabilitation training device using pneumatic inflation and deflation ofair cells. By alternating inflation and deflation of upper and lower air cells, the device makes the flexional and exten-sional movement for wrist rehabilitation. With the angular displacement sensor, it measures the flexion-extensionangle of the wrist during the training and the bending angle is used for the automatic control of the device. Usingthe sensor output, the regression equation was obtained to measure the bending angle of the wrist from a wrist reha-bilitation training device. The measurement error of the device was evaluated by comparing the measurement outputwith the angle from the photograph. The measurement error of wrist bending angle between the sensor and photowas 3.2 o in average. With additional test and improvement, the pneumatic wrist rehabilitation training device mightbe used for rehabilitation training. Key words: Rehabilitation, Wrist, Pneumatic, Flexion, Angle

Angular Displacement and Velocity Sensors Based on Coplanar Waveguides (CPWs) Loaded with S-Shaped Split Ring Resonators (S-SRR).

In this paper, angular displacement and angular velocity sensors based on coplanar waveguide (CPW) transmission lines and S-shaped split ring resonators (S-SRRs) are presented. The sensor consists of two parts, namely a CPW and an S-SRR, both lying on parallel planes. By this means, line-to-resonator magnetic coupling arises, the coupling level being dependent on the line-to-resonator relative angular orientation. The line-to-resonator coupling level is the key parameter responsible for modulating the amplitude of the frequency response seen between the CPW ports in the vicinity of the S-SRR fundamental resonance frequency. Specifically, an amplitude notch that can be visualized in the transmission coefficient is changed by the coupling strength, and it is characterized as the sensing variable. Thus, the relative angular orientation between the two parts is measured, when the S-SRR is attached to a rotating object. It follows that the rotation angle and speed can be inferred either by measuring the frequency response of the S-SRR-loaded line, or the response amplitude at a fixed frequency in the vicinity of resonance. It is in addition shown that the angular velocity can be accurately determined from the time-domain response of a carrier time-harmonic signal tuned at the S-SRR resonance frequency. The main advantage of the proposed device is its small size directly related to the small electrical size of the S-SRR, which allows for the design of compact angular displacement and velocity sensors at low frequencies. Despite the small size of the fabricated proof-of-concept prototype (electrically small structures do not usually reject signals efficiently), it exhibits good linearity (on a logarithmic scale), sensitivity and dynamic range.