Angular Sensor Research Articles

Transmission Lines Loaded With Bisymmetric Resonators and Their Application to Angular Displacement and Velocity Sensors

This paper is focused on the analysis of coplanar waveguides (CPWs) loaded with circularly shaped electric-LC (ELC) resonators, the latter consisting of two coplanar loops connected in parallel through a common gap. Specifically, the resonator axis is aligned with the CPW axis, and a dynamic loading with ELC rotation is considered. Since the ELC resonator is bisymmetric, i.e., it exhibits two orthogonal symmetry planes, the angular orientation range is limited to 90°. It is shown that the transmission and reflection coefficients of the structure depend on the angular orientation of the ELC. In particular, the loaded CPW behaves as a transmission line-type (i.e., all-pass) structure for a certain ELC orientation (0°) since the resonator is not excited. However, by rotating the ELC, magnetic coupling to the line arises, and a notch in the transmission coefficient (with orientation dependent depth and bandwidth) appears. This feature is exploited to implement angular displacement sensors by measuring the notch depth in the transmission coefficient. To gain more insight on sensor design, the lumped element equivalent-circuit model for ELC-loaded CPWs with arbitrary ELC orientation is proposed and validated. Based on this approach, a prototype displacement sensor is designed and characterized. It is shown that by introducing additional elements (a circulator and an envelope detector), novel and high precision angular velocity sensors can also be implemented. An angular velocity sensor is thus proposed, characterized, and satisfactorily validated. The proposed solution for angular sensing is robust against environmental variations since it is based on the geometrical alignment/misalignment between the symmetry planes of the coupled elements.

An Implementation of Remote Monitoring Standing Tree Diameter at Breast Height

Studies show that there is electric potential difference between the internal part of tree and the soil, but the mechanism is not clear, possibly associated with tree species, environmental factors and DBH (diameter at breast height) of tree. In order to research the mechanism and change rules, it is necessary to measure bioelectricity, environmental factors and DBH of tree, among which the DBH and its growth is an important indicator. A kind of DBH of tree and its growth automatic measuring system has been designed based on the angular displacement sensor. The system can realize remote monitoring function of DBH measurement and the growth, and can be set by structural parameters to measure the size of DBH. In this paper, the experiments require the DBH of tree ranges from 0~40cm, and calculation system can measure the DBH less than 0.0436mm theoretically, meeting the measurement requirements and providing reliable data for researching mechanism of trees. DOI: http://dx.doi.org/10.11591/telkomnika.v11i11.3489

Design of the Angular Displacement Sensor Based on Magnetoresistive Technology

The design of the angular displacement sensor based on magnetoresistive technology uses DSPIC30F3010 digital signal processor for computing. Having been amplified, magnetoresistive element output signal enters into the single-chip microprocessor A/D converter unit to operate together with the Hall components output signal operation processing, and ultimately generates the actual angular displacement values.

The Research of the Shock Angular Displacement Sensor

Impact resistance angular displacement sensors are widely used in motion mechanical system, which not only requires the sensor having the advantages of large measurement range, long life, also the sensor need to withstand shock and vibration. We use the finite element analysis on the key structure of the sensor and design the sensor circuit.. The sensor has the advantages of high strength shell and flexible packaging, and it can withstand the impact of the gravitational acceleration 100g on three directions.

Angular Acceleration Measurement Experiment Study of Stepping Motor on Single Clap Operation

Apparent rotational angular acceleration exist in the stepper motor operation processing, the stepper motor torque angle characteristics were described and the mathematical model of motor are constructed; The actual angular acceleration of stepper motor on single-step operation is measured by self-developed rotating angular acceleration sensor, the experimental results show that the angular acceleration fluctuations of stepping motor on three single clap operation are little greater than on six clap operation, and there are return oscillations of motor on three single clap operation are obviously more than on six clap operation; Finally, the experimental phenomenon reasons are analyzed, and the corresponding conclusions are obtained.

A Novel Angular Acceleration Sensor Based on the Electromagnetic Induction Principle and Investigation of Its Calibration Tests

An angular acceleration sensor can be used for the dynamic analysis of human and joint motions. In this paper, an angular acceleration sensor with novel structure based on the principle of electromagnetic induction is designed. The method involves the construction of a constant magnetic field by the excitation windings of sensor, and the cup-shaped rotor that cut the magnetic field. The output windings of the sensor generate an electromotive force, which is directly proportional to the angular acceleration through the electromagnetic coupling when the rotor has rotational angular acceleration. The mechanical structure and the magnetic working circuit of the sensor are described. The output properties and the mathematical model including the transfer function and state-space model of the sensor are established. The asymptotical stability of the sensor when it is working is verified by the Lyapunov Theorem. An angular acceleration calibration device based on the torsional pendulum principle is designed. The method involves the coaxial connection of the angular acceleration sensor, torsion pendulum and a high-precision angle sensor, and then an initial external force is applied to the torsion pendulum to produce a periodic damping angle oscillation. The angular acceleration sensor and the angle sensor will generate two corresponding electrical signals. The sensitivity coefficient of the angular acceleration sensor can be obtained after processing these two-channel signals. The experiment results show that the sensitivity coefficient of the sensor is about 17.29 mv/Krad·s2. Finally, the errors existing in the practical applications of the sensor are discussed and the corresponding improvement measures are proposed to provide effective technical support for the practical promotion of the novel sensor.

On the modeling of a capacitive angular speed measurement sensor

In the present article, a perceptive capacitive sensor for measuring angular speed of a rotating shaft is proposed. The proposed sensor is capable of measuring rotating shaft angular speed, and its changes. The proposed model’s sensing part is a suspended clamped–clamped micro-beam, which is parallel with two fixed substrates from the upper and lower sides through the micro-beam’s width surface. An electric circuit is used to give out capacitance change as a result of angular speed change, in output voltage. The micro-beam undergoes non-linear electro-static pressure that is induced due to the applied bias DC voltage. The suggested sensor has high sensitivity for a large range of working machines rotating parts angular speed measurement. The governing nonlinear partial differential equation of the transversal motion of the beam is derived and solved by step by step linearization (SSLM) and Galerkin weighted residual methods and the stable region of the sensor is determined. The effects of the applied bias voltage and geometrical properties of the micro-beam on the sensitivity and the range of the measurable angular speed of the sensor are discussed.

A robust approach for a filter-based monocular simultaneous localization and mapping (SLAM) system.

Simultaneous localization and mapping (SLAM) is an important problem to solve in robotics theory in order to build truly autonomous mobile robots. This work presents a novel method for implementing a SLAM system based on a single camera sensor. The SLAM with a single camera, or monocular SLAM, is probably one of the most complex SLAM variants. In this case, a single camera, which is freely moving through its environment, represents the sole sensor input to the system. The sensors have a large impact on the algorithm used for SLAM. Cameras are used more frequently, because they provide a lot of information and are well adapted for embedded systems: they are light, cheap and power-saving. Nevertheless, and unlike range sensors, which provide range and angular information, a camera is a projective sensor providing only angular measurements of image features. Therefore, depth information (range) cannot be obtained in a single step. In this case, special techniques for feature system-initialization are needed in order to enable the use of angular sensors (as cameras) in SLAM systems. The main contribution of this work is to present a novel and robust scheme for incorporating and measuring visual features in filtering-based monocular SLAM systems. The proposed method is based in a two-step technique, which is intended to exploit all the information available in angular measurements. Unlike previous schemes, the values of parameters used by the initialization technique are derived directly from the sensor characteristics, thus simplifying the tuning of the system. The experimental results show that the proposed method surpasses the performance of previous schemes.

Optical sensor for angular position measurements embedded in robotic finger joints

This paper presents the modeling and the design of an innovative angular position sensor able to be easily integrated into miniaturized robotic joints (a joint is mm large with a diameter of mm). The sensor working principle is based on the modulation of the light radiant power flux that goes from an InfraRed light emitting diode (IR LED) to a photodiode (PD) through a thickness-varying canal integrated into the joint itself. The LED and the PD are fixed on one of the links that compose the robotic joint, while the canal is integrated into the other link. A model for the interaction between the optoelectronic components is presented, validated, and used to design a robotic joint with the embedded angular sensor. The robotic joint has been characterized and use to implement a complete robotic finger with four embedded angular sensors. The tendon-driven robotic finger has been calibrated and experimentally tested.

Application of rotation rate sensors in an experiment of stiffness ‘reconstruction’

Preliminary results of an application of rotation rate sensors in dynamic identification of a vibrating beam are reported. Three rotational sensors, measuring the response of a cantilever beam to kinematic harmonic excitations are applied in the reconstruction of its stiffness. A successful reconstruction of 15% stiffness drops is demonstrated. With the development of angular sensors and the decrease in their cost one can expect further progress of this new area of vibration-based damage detection.

Segmentally Structured Disk Triboelectric Nanogenerator for Harvesting Rotational Mechanical Energy

We introduce an innovative design of a disk triboelectric nanogenerator (TENG) with segmental structures for harvesting rotational mechanical energy. Based on a cyclic in-plane charge separation between the segments that have distinct triboelectric polarities, the disk TENG generates electricity with unique characteristics, which have been studied by conjunction of experimental results with finite element calculations. The role played by the segmentation number is studied for maximizing output. A distinct relationship between the rotation speed and the electrical output has been thoroughly investigated, which not only shows power enhancement at high speed but also illuminates its potential application as a self-powered angular speed sensor. Owing to the nonintermittent and ultrafast rotation-induced charge transfer, the disk TENG has been demonstrated as an efficient power source for instantaneously or even continuously driving electronic devices and/or charging an energy storage unit. This work presents a novel working mode of TENGs and opens up many potential applications of nanogenerators for harvesting even large-scale energy.

A localization algorithm for railway vehicles based on sensor fusion between tachometers and inertial measurement units

The availability of a reliable speed and travelled distance estimation is relevant for the efficiency and safety of automatic train protection and control systems. This paper investigates the main features of an innovative localization algorithm that integrates tachometers and inertial measurement units. Nowadays, the estimation is performed by an odometry algorithm that relies on wheel angular speed sensors. The objective is to increase the accuracy of the odometric estimation, especially in critical adhesion conditions, through sensor fusion techniques based on Kalman filter theory. The Italian company ECM S.p.A. has supported the project, providing a custom inertial measurement unit based on micro electro-mechanical system sensors for the on-track testing of the algorithm. The preliminary results show a significant improvement of the position and speed estimation performances compared to those obtained with SCMT (Italian acronym for ‘Sistema Controllo Marcia Treno’) algorithms, currently in use on the Italian railway network. A wide set of simulated test results, showing the improvement of the estimation process, is presented and discussed. An accurate train navigation that scarcely relies on information from the infrastructure will open a road map for the development of a more and more effective and efficient exploitation of the railway infrastructure.

A Physiological Dynamic Testing Machine for the Elbow Joint

Background: The aim of our study was to develop a test setup combining realistic force transmission with physiological movement patterns at a frequency that mimicked daily use of the elbow, to assess implants in orthopedic joint reconstruction and trauma surgery.Methods:In a multidisciplinary approach, an in vitro biomechanical testing machine was developed and manufactured that could simulate the repetitive forceful movement of the human elbow joint. The construction involved pneumatic actuators. An aluminum forearm module enabled movements in 3 degrees of freedom, while motions and forces were replicated via force and angular sensors that were similar to in vivo measurements.Results:In the initial testing, 16 human elbow joint specimens were tested at 35 Nm in up to 5000 cycles at a range of 10° extension to 110° flexion. The transmitted forces led to failure in 9 out of the 16 tested specimens, significantly more often in females and small specimens.Conclusions:It is possible to construct a testing machine to simulate nearly physiological repetitive elbow motions. The prototype has a number of technical deficiencies that could be modified. When testing implants for the human elbow with cadaver specimens, the specimen has to be chosen according to the intended use of the implant under investigation.

Test rig for measuring the center of gravity coordinates and inertia tensor of spacecrafts: Data acquisition and control system

We consider data acquisition and control system used in the test rig for measuring the center of gravity coordinates and inertia tensor of spacecrafts. Structure of the system is described. Technical specifications and metrological parameters are presented for the module which measures static and dynamic signals of strain gauge dynamometers and for the module which measures the signals of angular oscillation sensor installed on the test rig measuring platform; these oscillations are generated using electric motors and special control hardware. Finally, we describe the system software used to acquire and process the data and to display the measurement results.

Optimization and Modeling of Ink-Jet Printed Flexible Position Sensor

This paper presents how geometrical and technological parameters of inductive angular position sensor, fabricated on flexible substrate, influence its characteristics. In our earlier work, the angular position sensor has been already presented but for 60° stroke. In presented work, the design and optimization have been performed for 90° stroke, which is extensively used, for example, in automotive applications. For three different designs of meander rolled coils, width of segments, substrate thickness and relative distance between outer and inner coils have been changed in order to find optimal sensor structure. The proposed sensor is low-cost, easily fabricated and its parameters can be adapted for different angular strokes and applications.

Using 9-Axis Sensor for Precise Cardiosurgical Robot Master Angular Position Determination

The article will focus on the presentation of the possibility of practical application of integrated 9-axis sensor, in which magnetic field, acceleration and angular velocity 3-axis sensors were used. Particular emphasis will be placed to describe the mentioned sensors data fusion algorithm, which is necessary for precise and unequivocal determination of the angular position of the tested device. Another presented issue is a selection of an appropriate data filtering algorithm with selected filtering parameters. Additionally, the possibility of implementing described solutions in the angular positions measurement system of cardiosurgical Robin Heart robot master will be shown. Also, a design concept of mentioned robot master along with its working principle will be mentioned.

Error Calibration System for Time Grating Angular Displacement Sensor

A calibration system was developed for time grating angular displacement sensors to calibrate errors of this type of sensor. In the system, the motor was controlled by ARM processor according to the setting value coming from the USB port of the computer, and therefore the motor outputted angular displacement values. Meanwhile, with the motor turning, the optical grating, which was used as the criterion instrument, and time grating turned together corresponding angular displacements. Several displacement values from a circle of sensors of time grating and optical grating were sent to computer by serial port to be processed. Furthermore, an error calibration algorithm, which was based on the least square method (LMS), was used in this calibration system. The precise of time grating can reach to ±0.7″after calibrating using this algorithm and the process of error calibration can be automatically made by the computer.

A More Reliable and Easy Manufacturing Wireless Thermal Convection Angular Accelerometer without any Movable Parts and Grooved Cavity

Five novel ideas are proposed in this paper to integrate an active RFID tag with a thermal convection angular accelerometer on a flexible substrate, thus the device is a wireless sensor. The first innovative idea is that this device is made directly on a flexible substrate without any movable parts and grooved cavity, so it is very easy to make and reliable. The second new idea is that the flexible substrate is plastic or polyimide, the thermal conductivity of the flexible substrate is much lower than the traditional silicon, and thus it can save more power and very useful for mobile operation. The third new idea is that the inert xenon gas is filled in the chamber to conduct the heat instead of CO2 used in the traditional thermal convection accelerometer. Carbon dioxide can produce oxidation effect to the heater and thermal sensors, while the Xe gas will not. The fourth new idea is to apply a hemi-spherical chamber; it is more streamline in nature with less drag effect. Thus it can ease the fluid flow and yield quicker response. The fifth new idea is the most powerful one to integrate the angular accelerometer with an active RFID tag on the same flexible substrate, thus the device becomes a more useful wireless angular acceleration sensor. In this paper we only use the hemi-spherical chamber filled with Xe gas. The sensitivity is 258 ◦ C/(rad/s 2 ) and the response time is 81ms.

A novel absolute angular position sensor based on electromagnetism

Based on the law of electromagnetic induction, a novel contactless absolute angular position sensor has been designed in the literature. It is mainly composed of three parts: two emitters, an annular encoder and a signal processing circuit. The emitter integrates a main coil and two groups of secondary windings, each of which comprises two series-wound coils with inverse enwinding directions. N and (N−1) copper sheets with regular shapes are arrayed uniformly in the outer and inner circles of the encoder which are corresponding to the two emitters respectively. The main coil stimulated by the external current can generate a magnetic field, which can be detected by two groups of secondary windings and a corresponding voltage signals will be exported. As the emitter rotated over any two neighboring copper sheets of the encoder, a period of sine and cosine signals will be outputted by two groups of secondary coils. The absolute angle position signals can be calculated based on the relationships between angles calculated by N and (N−1) periods of sine and cosine signals produced by the inner and the outer circles of emitters and the angles the emitter has rotated around the rotation axis. Experiment has been performed on a prototype of the angular position sensor and the results demonstrate the proposed scheme is feasible. Theoretic precision and testing error analysis of the sensor has been pursued at the end of the paper.

On-track Measurements of Neck Movements and Muscle Activity during Motocross Sessions with or without Neck Brace

This work analyse the movements and the muscular activity during motocross sessions and how a neck brace influence both. These movements are measured in terms of angles using two Biometrics® angular sensors (one for bi- planar flexion and one for torsion); the muscle activity is registered using four pairs of electrodes (muscle selected: Sterno-Cleido-Mastoid left and right, Trapezium left and right). From the results obtained, we can conclude that the pilot wants to focus the attention to the next jump or obstacle while accelerations of different nature are acting on the neck, therefore isometric contractions are predominant. The fact that the brace did not reduce the rotational range of motion is a positive result because the pilot field of view is not modified which is a safety requirement. According to the evidence of a fatigue effect, the brace is useful not only to protect the pilot during accidents but also as a supporting device during driving sessions.