Abstract: 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

Abstract: Contact occurrence between disk and stator as result of undesirable vibrations produced by eccentricity of the disk is one of the most destructive and common phenomena in rotor dynamics systems. In this work, utilizing tuned mass damper (TMD) and nonlinear energy sink (NES) are suggested as a solution for preventing contact occurrence. The mass and angular position of absorbers determine their efficiency for resisting the eccentricity force produced by the disk, and their stiffness and damping coefficients determine the displacement scope of the absorber. In order to efficiently design absorbers, optimization is proposed. In this suggested optimization process, complex averaging method is used in order for deriving the equations of motion of the system in presence of dynamic absorbers at the steady state condition. Afterwards, for determining trustworthiness of each absorber’s performance, system’s behavior is studied for different values of its parameters such as rotational speed, stiffness, clearance and eccentricity in presence of each absorber. From the obtained results, it can be perceived that TMD and NES are as efficient as possible and they have exactly the same positive influence on the system’s vibrations. The reliability of the proposed optimization process can be determined by the results.

Abstract: This paper presents a sensing mechanism of a rotary magnetic encoder based on the time grating approach. The relationship between spatial displacement and time standard is built by the orthogonal alternating magnetic field in the rotational motion. Time pulses serve as measurement standard and are counted to measure the angular displacement. Therefore, this displacement detection method is called time grating. The alternating magnetic field is generated using the magnetic ring rotating with the shaft. Pairs of tunnel magneto resistance sensors are separated by 90° electrically angles to induce the alternating magnetic field and output orthogonal voltage signals. The travelling wave would be generated by signal processing, which has the phase shift with the rotating shaft. Thus, the rotation angle is measured by counting the time pluses corresponding to the phase difference. A rotary magnetic encoder has been fabricated to evaluate the proposed method. Experimental results indicate that the measurement has high resolution and stability.

Abstract: In this paper, we propose a protocol for the estimation of angular displacement based upon orbital angular momentum and an SU(1,1)-SU(2) hybrid interferometer. This interferometer consists of an optical parametric amplifier, a beam splitter, and reflection mirrors; the balanced homodyne detection is used as the detection strategy. The results indicate that super-resolution and super-sensitivity can be achieved with an ideal scenario. Additionally, we study the effect of photon loss on resolution and sensitivity, and the robustness of our protocol is also discussed. Finally, the advantage of our protocol compared with an SU(1,1) protocol is demonstrated, and the merits of orbital angular momentum-enhanced protocol are summarized.

Abstract: A wide dynamic range, high precision, non-contact and large bandwidth angular displacement measurement (ADM) is greatly necessary for the applications such as industrial control and military equipment. This paper proposes a simple and effective ADM method based on Doppler Effect, heterodyne detection and diffuse reflection, which can fulfill these requirements simultaneously. Two beams of parallel light generated by a pair of laser Doppler vibrometers are incident upon the surface of rotational target, then data processing unit acquires the velocity of dual laser incident points on the moving target, and resolves the rotational angular displacement and translation displacement of target through the relationship between dual laser beams dynamically. Several major measurement errors that may affect the ADM accuracy are analyzed. A high precision rotary table is used as an angular displacement standard to verify the measurement range and accuracy, the verification experiment shows that the measurement range is not less than ±10° and the measurement accuracy is 0.0362° based on the method. After using a polynomial error compensation, the measurement accuracy can be promoted to 0.0088°, and this compensation method can be applied to real time measurement.

Abstract: Conventional methods for the calibration of angle encoders typically only consider the graduation error of the encoder's circular scale. However, the radial motion of the circular scale during its rotation, due to its eccentricity and the axis of rotation radial error motion, can also introduce noticeable errors to the angle measurement in most practical applications. Based on the analysis of the influence of radial motion, an optimal-arrangement-based four-scanning-heads error separation technique for in situ self-calibration of angle encoders is presented. This Fourier-based technique uses the basic self-calibration model to measure the first-order Fourier component of the encoder error which includes the contribution of eccentricity. Meanwhile, the separation technique is utilized to separate the residual Fourier components of the graduation error from the measurement deviation due to radial error motion. The effect of the scanning heads' angular position errors on the calibration results is discussed. Optimal arrangements of the four heads are achieved to avoid the suppression of the Fourier components, and reduce the propagation of errors. Numerical results and experimental comparisons demonstrate the effectiveness of the proposed method. Moreover, this technique can also be used for measuring the spindle radial error motion for some users.

Abstract: For reducing the sticking or stick–slip phenomenon, this paper proposed a new torsional oscillator which could produce a circumferential torque vibration in the drilling process. Based on the working principle and fundamental structure, the generation mechanism of torsional vibration and the relationships of the mechanical parts are derived. Then, the dynamic model is established according to the drilling operation condition. With this, the further analysis of changing relationship between the inlet flow and torque is studied. The angular displacement and velocity of the valve body are analyzed according to the dynamics theory models. With the combination of the theoretical analysis model, the parameter studies are carried out by numerical example calculation. Finally, experiment test is conducted to identify the accuracy and reliability of the calculation method under the corresponding working conditions. The results show that with the constant pressure the average torque is proportional to the inlet flow. However, while the inlet pressure is invariable, the collision period is inversely proportional to the inlet flow, and the angular displacement and velocity are proportional to the inlet flow. The research results can provide references for the design and application of the torsional vibration tools, which is potential and significant in drilling engineering.

Abstract: A key problem in drill string dynamics is the stick–slip in deep and large displacement horizontal wells that may lead to the decline in drilling performance or cause tool failure, which may eventually cause underground accidents. Therefore, the research on the production safety, ROP, and increased efficiency in relation to stick–slip theory and practical stick–slip reduction is highly relevant, especially in complex drilling conditions. On this basis, this study takes the new constant torque tool as the engineering background and establishes the working mechanism analytical model of stick–slip reduction and torque constant. A helical dynamic model is established to solve the core problem of the constant torque tool. Then, the differential equation of the helical spline drive motion is deduced. The motion of the helical spline mandrel is calculated, and its analytical results are compared with simulation results. Findings show that the laws of angular displacement, angular velocity, axial displacement, and axial velocity are consistent with the simulation results when the helical spline mandrel moves up or down. The established theoretical model can promote the development of drill string dynamics in new drilling conditions. Moreover, the proposed designing methods can provide new ideas for the development of a stick–slip reduction tool. The results can be further used as reference for key parameter determination and stick–slip reduction technology optimization.

Abstract: We propose a simple scheme for magnetic angular position sensor based on current-induced spin-orbit torque effect. A full range detection of 360° is realized with a pair of Hall crosses made of heavy metal/ferromagnet heterostructures. The current axes of the two Hall crosses are aligned orthogonal to each other, such that when both devices are subject to a rotational in-plane magnetic field, the differential Hall voltage due to current pulses of opposite polarity exhibits a sine and cosine angular dependence on the field direction, respectively. The field rotational angle is then calculated from the sine and cosine output signals via the arctan2 function. A linear correspondence between the calculated and actual field angle is obtained in the field range of 500–2000 Oe, with an average angle error of 0.38°–0.65°.

Abstract: A drive module for a motor vehicle includes a housing, an electric machine, a rotor carrier, and an angular position sensor. The electric machine is for generating a drive torque and includes a rotor. The rotor carrier is connected substantially rotationally fixed to the rotor and mounted such that it can be rotated at least radially. The angular position sensor is for measuring an angular position of the rotor carrier. The angular position sensor is arranged such that the angular position of the rotor carrier or a first component substantially rotationally fixed to the rotor carrier can be detected by the angular position sensor in relation to a second component fixed to the housing.

Abstract: In this paper, we propose a protocol for angular displacement estimation based upon orbital angular momentum coherent state and a SU(1,1)-SU(2) hybrid interferometer. This interferometer consists of an optical parametric amplifier, a beam splitter and reflection mirrors, hereon we use a quantum detection strategy $\---$ balanced homodyne detection. The results indicate that super-resolution and super-sensitivity can be realized with ideal condition. Additionally, we study the impact of photon loss on the resolution and the sensitivity, and the robustness of our protocol is also discussed. Finally, we demonstrate the advantage of our protocol over SU(1,1) and summarize the merits of orbital angular momentum-enhanced protocol.

Abstract: We report on an orbital-angular-momentum-enhanced scheme for angular displacement estimation based on two-mode squeezed vacuum and parity detection. The sub-Heisenberg-limited sensitivity for angular displacement estimation is obtained in an ideal situation. Several realistic factors are also considered, including photon loss, dark counts, response-time delay, and thermal photon noise. Our results indicate that the effects of the realistic factors on the sensitivity can be offset by raising orbital angular momentum quantum number $\ell$. This reflects that the robustness and the practicability of the system can be improved via raising $\ell$ without changing mean photon number $N$.

Abstract: Summary The rocking response of a rigid, freestanding block in two dimensions typically assumes perfect contact at the base of the block with instantaneous impacts at two distinct, symmetric rocking points. This paper extends the classical two-dimensional rocking model to account for an arbitrary number of rocking points at the base representing geometric interface defects. The equations of motion of this modified rocking system are derived and presented in general terms. Energy dissipation is modeled assuming instantaneous point impacts, yielding a discrete angular velocity adjustment. Whereas this factor is always less than unity in the classical model, it is possible for this factor to exceed unity in the presented model, yielding a finite increase in the angular velocity at impact and a markedly different rotational response than the classical model predicts. The derived model and the classical model are numerically integrated and compared to the results of recent shake table tests. These comparisons show that the new model significantly enhances agreement in both peak angular displacement and motion decay. The equations of motion and the energy dissipation of the presented model are further investigated parametrically considering the size of the defect, the number of rocking points, and the aspect ratio and size of the block.

Abstract: This paper reports a method for micrometer-scale linear and angular displacement measurement based on a gradient grating period guided-mode resonance (GGP-GMR) filter. When the filter is mounted on a moving or rotating object, the displacement on the object can be observed through the changes in the resonant wavelength, which are detected by the GGP-GMR filter. In this paper, the GGP-GMR filter comprised grating periods from 250 to 550 nm with 2-nm increments. Each period comprised 100 repeated cycles, resulting in a total length of 6 mm. For linear displacement, we achieved an average sensitivity of 67 nm/mm for a detection range of 6 mm and a theoretical limit of detection of $3~\mu \text{m}$ . To demonstrate the measurement of angular displacement, the GGP-GMR filter was attached to a cylinder with a diameter of 8 cm. The experimental results revealed an average sensitivity of 51.7 nm/° for a range of 7° and an experimental limit of detection of 0.002°.

Abstract: The number of studies on microgrippers has increased consistently in the past decade, among them the numeric simulations and material characterization are quite common, while the metrological issues related to their performance testing are not well investigated yet. To add some contribution in this field, an image analysis-based method for microgrippers displacement measurement and testing is proposed here: images of a microgripper prototype supplied with different voltages are acquired by an optical system (i.e., a 3D optical profilometer) and processed through in-house software. With the aim to assess the quality of the results a systematic approach is proposed for determining and quantifying the main error sources and applied to the uncertainty estimation in angular displacement measurements of the microgripper comb-drives. A preliminary uncertainty evaluation of the in-house software is provided by a Monte Carlo Simulation and its contribution added to that of the other error sources, giving an estimation of the relative uncertainty up to 3.6% at 95% confidence level for voltages from 10 V to 28 V. Moreover, the measurements on the prototype device highlighted a stable behavior in the voltage range from 0 V to 28 V with a maximum rotation of 1.3° at 28 V, which is lower than in previous studies, likely due to differences in system configuration, model, and material. Anyway, the proposed approach is suitable also for different optical systems (i.e., trinocular microscopes).

Abstract: Rotation and transportation of micro-particles using ultrasonically-driven devices shows promising applications in the fields of biological engineering, composite material manufacture, and micro-assembly. Current interest in mechanical effects of ultrasonic waves has been stimulated by the achievements in manipulations with phased array. Here, we propose a field synthesizing method using the fewest transducers to control the orientation of a single non-spherical micro-particle as well as its spatial location. A localized acoustic force potential well is established and rotated by using sound field synthesis technique. The resultant acoustic radiation torque on the trapped target determines its equilibrium angular position. A prototype device consisting of nine transducers with 2 MHz center frequency is designed and fabricated. Controllable rotation of a silica rod with 90 μm length and 15 μm diameter is then successfully achieved. There is a good agreement between the measured particle orientation and the theoretical prediction. Within the same device, spatial translation of the silica rod can also be realized conveniently. When compared with the existing acoustic rotation methods, the employed transducers of our method are strongly decreased, meanwhile, device functionality is improved.

Abstract: Волновые зубчатые передачи нашли широкое применение в приводах машин, имеющих высокую кинематическую точность. Именно такие передачи в основном определяют точностные характеристики привода. Погрешности изготовления и установки различных деталей могут возбуждать поперечные колебания генератора волн, приводящие к периодическому изменению углового положения выходного вала и, следовательно, к повышению кинематической погрешности волновой зубчатой передачи. Амплитуда поперечных колебаний генератора зависит от его частоты, поэтому судить о возможности применения волновых передач в высокоточных приводах можно только по амплитудно-частотным характеристикам кинематической погрешности. Для теоретического определения указанных характеристик необходимо знать зависимость угла поворота выходного вала от поперечных перемещений кулачка. Предложена методика определения этой зависимости с помощью пространственной математической модели волновой зубчатой передачи. Для передачи ВЗП-160 расчетным путем показано, что при увеличении поперечных смещений кулачка двухволновое зацепление может переходить в одноволновое. Установлено, что вычисление угла поворота выходного вала при двухволновом зацеплении требует решения задачи упругого взаимодействия элементов передачи. Упрощенные формулы, используемые в различных информационных источниках, можно применять только при одноволновом зацеплении и однокромочном контакте зубьев.

Abstract: Super-resolved angular displacement estimation is of crucial significances for quantum information process and optical lithography Here we report on and experimentally demonstrate a protocol for angular displacement estimation based on a coherent state containing orbital angular momentum In the lossless scenario, with using parity measurement, this protocol can theoretically achieve 4$\ell$-fold super-resolution with quantum number $\ell$, and shot-noise-limited sensitivity saturating the quantum Cramer-Rao bound Several realistic factors and their effects are considered, including nonideal state preparation, photon loss, and imperfect detector Finally, given mean photon number $\bar N=2297$ and $\ell=1$, we show an angular displacement super-resolution effect with a factor of 788, and the sensitivity approaching shot-noise limit is reachable

Abstract: We consider two types of homogeneous reduced elastic media with finite dynamic spin. One is Kelvin’s medium, whose particles have axial symmetry and may freely rotate about their axes. Its equations are analogous to those of ferromagnetic insulators near the state of magnetic saturation. Another one is a gyrostatic medium, consisting of spherical body-points containing rotors. Gyroscopic term prevails in the dynamics of both continua. Axes in the reference configuration are collinear. We consider reduced media, whose elastic energy does not depend on the gradient of turn, under the follower body torque, proportional to the rotational displacement. We obtain that there exist polarised shear harmonic waves. The only exception is for the wave vector orthogonal to the axes: in this case we have two shear plane waves, one has a band gap and another one is classical. For the direction of wave propagation parallel to the unit vector, polarisation is circular and does not depend on frequency. In all other cases, polarisation is elliptic and depends on the frequency and on the direction of the wave propagation relatively to the axes. If the external follower torque is positive (reduces the rotational displacement of the body-point), one of the polarised waves has a band gap and another one not. Changing the external loading, we change the band gap. If we apply a negative torque, depending on the direction of the wave propagation and parameters we may obtain band gaps for both branches and a decreasing part of dispersion curve for one of them just above the cut-off frequency. Thus this media behave as smart acoustic metamaterials, single or double negative, depending on the wave polarisation, external torque, parameters and the frequency domain.

Abstract: The invention provides a multi-sensor fusion based SLAM and obstacle avoidance mobile chassis capable of improving the mapping accuracy and achieving accurate obstacle avoidance, and belongs to the technical field of robots The mobile chassis comprises: an environment sensing module configured to acquire environmental data around a chassis body through a laser sensor and a visual sensor; a bottomsensing module configured to acquire the rotation directional angular displacement of the chassis body and surrounding obstacle information; a control module configured to: process the environmentaldata to construct a map, determine a position of an obstacle according to the obstacle information, acquire a motion control instruction for the chassis body, transmit the command to a servo drive module to realize obstacle avoidance, and configured to receive a linear displacement of the chassis body returned by the servo drive module, and acquire a current pose of the chassis body according tothe rotation directional angular displacement; and the servo drive module configured to drive the chassis body according to the motion control command so as to achieve speed control, and acquire the linear displacement information of the chassis body

Abstract: Proportional velocity (PV) and proportional integral (PI) controllers are designed to regulate the angular position and angular velocity, respectively, of a DC motor system with a pointwise time-delay in the feedback loop. Because of the time-delay, the system is described by delay-differential equations which have infinitely many modes that can not be assigned by using classical pole placement methods. The proposed method is based on minimizing the real part of the rightmost closed-loop mode, i.e., spectral abscissa, as a function of the controller parameters. The effectiveness of the method is illustrated by simulations and real-time experiments.

Abstract: The problem of synthesis of adaptive dynamic filter is presented in the form of problem of quasi-optimal control. The solution is obtained based on the theorem of the maximum of the function of the generalized power and analysis of the Lagrangian along characteristic trajectories in phase space. This allows to construct a model of controlled motion that can be represented in a quasilinear form. The obtained equation of the adaptive filter of the dynamic estimation of the motion parameters differs from the known equations by its feedback structure. On the basis of mathematical modeling it is shown that estimations of the proposed filter provide an increase in accuracy with less computational costs.

Abstract: The focus of this paper is on the control design and simulation of twin rotor aero-dynamical system (TRAS). The challenges for control design in these systems lie in their nonlinearity and the inherent cross coupling between motion in the vertical and horizontal directions. Working from a highly nonlinear, dynamically coupled, mathematical model, controller design is presented for the angular position/velocity in vertical and horizontal planes of motion. Three linear control methods were developed and optimized to control the TRAS, namely full state feedback (FSF), linear quadratic regulator (LQR), and PID control. Simulation and experimental results show trade-off between these control methods. Although better performance was achieved with LQR, more effort was needed. The PID control has always proved to be a simple approach that works well with linear models. However, in this study case the performance was strongly affected by the coupling effect as demonstrated by simulation and experimental results

Abstract: A new approach to position the Technical Vision System (TVS) laser ray, which determines the 3D coordinates of any objet under observation in the TVS Field-of-View (FOV), using the Digital Controller LM629 is proposed. This approach reduces significantly the angular position error by at least 82.97 per cent, compared to the previous implementation of a proportional algorithm in closed-loop configuration, using directly a single microcontroller. Present paper identifies the behavior of the DC motor shaft, which represents the main actuator of the TVS Positioning Laser (PL), adjusting an internal trapezoidal velocity profile, generated as the control signal for the DC motor. The reference value for the DC motor actual angular position is computed, using the Digital Controller LM629, which also tracks this actual angular position. The methodology of the new approach is developed in accordance with theoretical concepts. In addition, experimental results show the comparison between the previous implementation and this new approach.