Output Angle Research Articles

Solar photovoltaic water pump performance optimization by using response surface methodology

AbstractThe constant depletion of the existing energy sources and their environmental effects have generated interest in employing renewable energy sources to power water pumping systems, such as solar‐photovoltaic. The research addresses the optimal photovoltaic (PV) power output, solar radiation, operating head, and tilt angle for maximum solar energy used to capture more solar radiation for solar water pumping for irrigation purposes. In order to get the best performance from the solar PV water pump, such as discharge (Q), hydraulic power (PH), pump efficiency (ήp), and overall efficiency (ήo), the design of experiments‐based response surface methodology was implemented in this work. The data required for the RSM model were obtained from the experimental work performed at location 28.67° N, 77.21° E, Delhi, India. The experiments performed at five different ranges of input variables PV power output (4000, 4250, 4500, 4750, and 5000 W), Solar radiation (200, 350, 500, 650, and 800 W/m2), operating head (15, 20, 25, 30, and 35 m) Tilt angle (5°, 10°, 15°, 20°, and 25°). The best output parameters The best conditions for a solar PV water pump (16.8 m3/h discharge, 1.85 kW hydraulic power, 81.15% pump efficiency, and 16.12% overall efficiency) were discovered to be Po 5000 W, SA 260 W/m2, Head 35 m, and TA 19°. The predicted result was validated using an RSM‐based solution, and the error% was found to be within acceptable limits (>5%). The desirability 0.963 of the model was indicating the good solution.

Software-Reconfigurable Multistage Constant Current Wireless Battery Charging Based on Multiharmonic Power Transmission

Wireless power transfer (WPT) technology has been widely applied in electric vehicle battery chargers because of its convenience, reliability, and safety. A typical battery charging profile consists of a constant current (CC) charging process followed by a constant voltage charging process. Recently, a multistage constant current (MSCC) charging profile is proposed to increase the charging speed, flexibility, and other performances. MSCC charging profile consists of multiple CC charging processes, which are applied to the battery in turn. This article proposes a low-cost software-reconfigurable MSCC charging technique for a typical single-stage dc–dc series–series compensated WPT converter using multiple high-order harmonics power transmission approach. Such a technique does not require any additional component and it can achieve inherent load-independent CC output and zero phase angle input characteristics. Moreover, it provides a precharge process for deeply discharged batteries to increase their lifetime. A scaled-down design example and the corresponding laboratory prototype are implemented to verify the proposed method.

The Concept and Understanding of Synchronous Stability in Power Electronic-Based Power Systems

Synchronous stability in power systems is of essential importance for system safety and operation. For the phase-locked loop (PLL)-based synchronous stability in power electronic-based power systems, which has recently stimulated interest in researchers in the field of electrical power engineering, but is still controversial, this paper divides the topic into two aspects, including the PLL device stability and the system stability. It is found that the PLL device is always stable and the error between the PLL output angle θpll and the terminal voltage angle θt is always finite. Therefore, the synchronization of power electronic-based power systems should be understood as the output synchronization between the electrical rotation vectors (θt or θpll) from each item of grid-tied equipment, rather than the synchronization of the PLL device itself. In addition, it is found that θpll plays an active role in the system synchronization dynamics not only in electromagnetic timescales but also electromechanical timescales and it could be selected as a dominant observable. In this paper, the concept of synchronous stability is well clarified. These findings are well supported by theoretical analyses and MATLAB/Simulink simulations, and thus could provide insights on the synchronous stability mechanism.

A tilting system design and simulation of ground penetrating radar

In this paper, a tilting system of ground penetrating radar by 5R1C 6-bar linkage mechanism is proposed. The kinematic function of hydraulic cylinder and the output angle is given in explicit format. The quasi-static formulation of the tilting system is proposed to calculate the shaft and revolute force. The simulation of mechanism via ADAMS and an experiment is made to verify the design. The maximum stress is exposed in curved shaft and the worst working condition is the tilt condition. It proves the validity of tilting system that both mechanism and hydraulic system work well in the loading condition and unloading condition.

A Parameter Tuning Method for a Double-Sided Compensated IPT System With Constant-Voltage Output and Efficiency Optimization

A parameter tuning method is critical for inductive power transfer (IPT) systems because it ensures constant output and reduces reactive power. This is especially true for the double-sided <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> (DS- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> ) compensated IPT system due to its high parameter tuning freedom. This article proposes a parameter tuning method for the DS- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> compensated IPT system. By reconfiguring key resonant parameters, the load-independent constant voltage (CV) output and zero phase angle (ZPA) can be achieved without varying operating frequency. Based on this, two compensation factors for the primary and secondary compensation inductances are defined, and the performance of the IPT system under different compensation factors and the optimal matching criterion of these two factors are investigated in detail. By optimizing these two compensation factors, the overall system efficiency is improved over the entire power range without affecting the property of CV and ZPA. A 2-kW experimental prototype is built to validate the practicability of the proposed tuning method. The experimental results indicate that when the dc load varies from 13.4 to 134 Ω, ZPA can always be achieved, and the output voltage fluctuation is only 4.6 V. The peak efficiency reaches 92.14% at a 1.6-kW output power.

Flat variable liquid crystal diffractive spiral axicon enabling perfect vortex beams generation

A transparent variable diffractive spiral axicon (DSA) based on a single LC cell is presented. The manufactured DSA can be switched between 24 different configurations, 12 convergent and 12 divergent, where the output angle is varied as a function of the applied topological charge. The active area of the device is created using a direct laser writing technique in indium-tin oxide coated glass substrates. Liquid crystal is used to modulate the phase of the incoming beam generating the different DSA configurations. The DSA consists in 24 individually driven transparent spiral shaped electrodes, each introducing a specific phase retardation. In this article, the manufacture and characterization of the tunable DSA is presented and the performance of the DSA is experimentally demonstrated and compared to the corresponding simulations.

A CC-Type IPT System Based on S/S/N Three-Coil Structure to Realize Low-Cost and Compact Receiver

The characteristics of load-independent constant current (CC) output and zero phase angle (ZPA) operation are required in many scenarios of inductive power transfer (IPT) applications. However, the existing topologies with CC output characteristics usually need to introduce additional compensation components on the receiving side to compensate for reactive power and achieve the preset function. This not only increases the occupied space of the receiving side, but also increases the cost and weight. Therefore, this study proposes a new IPT system based on an S/S/N three-coil structure. The proposed system can achieve the CC output function and an operation nearly ZPA and zero-voltage switching (ZVS) through flexible parameter design. Moreover, there are no compensation components on the receiving side of the proposed system, which guarantees a low-cost, lightweight, and compact receiver. Firstly, a comprehensive analysis of the proposed S/S/N three-coil structure IPT system that implements CC output characteristics and ZPA operation is provided. Then, the conditions for realizing ZVS are discussed in terms of parameter design and the sensitivity of CC output characteristics to the changes in compensation capacitance parameters. Furthermore, the proposed S/S/N three-coil structure IPT system is compared with previous related studies to reflect its advantages. Finally, the correctness of the theory is verified by simulation and experiment.

Active terahertz beam steering based on mechanical deformation of liquid crystal elastomer metasurface

Active metasurfaces are emerging as the core of next-generation optical devices with their tunable optical responses and flat-compact topography. Especially for the terahertz band, active metasurfaces have been developed as fascinating devices for optical chopping and compressive sensing imaging. However, performance regulation by changing the dielectric parameters of the integrated functional materials exhibits severe limitations and parasitic losses. Here, we introduce a C-shape-split-ring-based phase discontinuity metasurface with liquid crystal elastomer as the substrate for infrared modulation of terahertz wavefront. Line-focused infrared light is applied to manipulate the deflection of the liquid crystal elastomer substrate, enabling controllable and broadband wavefront steering with a maximum output angle change of 22° at 0.68 THz. Heating as another control method is also investigated and compared with infrared control. We further demonstrate the performance of liquid crystal elastomer metasurface as a beam steerer, frequency modulator, and tunable beam splitter, which are highly desired in terahertz wireless communication and imaging systems. The proposed scheme demonstrates the promising prospects of mechanically deformable metasurfaces, thereby paving the path for the development of reconfigurable metasurfaces.

A novel design of compact tilt stage with spatially distributed anti-symmetric compliant mechanism

The tilt stage with high precision angular motions has emerged as one of the key enabling components in many advanced engineering applications, such as adaptive optics, space communication and ultra-high precision manufacturing, where the design requirements on large deflection angle, high natural frequency and compact size have general challenges. In this research, a 3D-printing compatible anti-symmetric compliant mechanism is proposed, composed of spatially distributed positive Poisson’s ratio structural unit (P-layer) and negative Poisson’s ratio structural unit (N-layer). Under the same tension, the P-layer and N-layer can generate transverse shrinkage deformation and expansion deformation respectively, thus driving the end-effector with a larger angular deflection without sacrificing the natural frequency. The proposed tilt stage with anti-symmetric compliant mechanism achieves a more compact size, as well as better motion behaviors. A theoretical model is also established to analyze the static performance and predict the output angle of the proposed design. The experiments show that the developed tilt stage can achieve a deflection range of 9.23 mrad and a natural frequency of 1086 Hz, with significant improvement over existing results. • Development of spatially distributed anti-symmetric compliant mechanisms compatible with 3D printing. • Working principle and model analysis on the thrust-tension based tilt motions. • Development of a high performance compact tilt stage with a large operating range (9.23 mrad) and a high natural frequency (1086 Hz). • Experimental validations of the proposed design and modeling method.

Dance pose capture and recognition based on heterogeneous sensors

In order to capture the movement posture of dancer in real time and effectively, a dancer motion and posture capture system based on heterogeneous sensors is proposed. Starting from the data processing of heterogeneous sensors in a single node, the single attitude measurement node of the system can be used to collect the initial posture data in the process of dancer motion in real time, achieve accurate capture of dancer movements, and filter and fuse the original motion data. In order to verify the performance and accuracy of the designed dancer movements capture system, relevant experiments are designed to verify it. The experimental results show that the algorithm designed in this experiment basically solves the interference problem of magnetic field and acceleration on attitude solution, and the attitude solution accuracy can basically meet the requirements. The fitting degree of the comparison between the extracted angle of the video sequence and the output angle of the sensor can basically meet the requirements, and the angle deviation is kept within 1 degree. The system can capture the dancer movements of the whole body and the hand, and the experimental results can meet the requirements basically, which has certain reference value.

Stereolithography 3D printing of transparent resin lens for high-power phosphor-coated WLEDs packaging

Advanced lens fabricating techniques are urgently required for the development of white light-emitting diodes (WLEDs) packaging, due to the traditional LED lenses molding possesses presents many disadvantages like high cost, long-fabrication period, less compactness and low accuracy. The current study demonstrated the fabrication of lenses with transparent resin utilizing stereolithography (SLA) 3D printing. The SLA 3D printing parameters were optimized to accurately regulate the spheric and ellipsoidal lenses with the smooth surface and the acceptable transmittance. The illuminances, lighting efficiency (LE) and lighting distribution curves of the SLA-fabricated lens packaged WLEDs highly depended on the lens structure. The WLEDs with lower lens height exhibited more intense lighting energy density, higher LE and wider light output angle. SLA 3D printing offers a flexible approach of fabricating WLED lens, which provides a novel technical route for WLEDs to meet different lighting requirements.

Fabry-Pérot angle sensor using a mode-locked femtosecond laser source.

An angle sensor based on multiple beam interference of a Fabry-Pérot etalon employing a mode-locked femtosecond laser as the measurement beam is proposed. Output angles are evaluated by using estimated local maxima within a measurement bandwidth of an output fringe spectrum detected by an optical spectrum analyzer. In the proposed method, fringe spectra produced by beams from transmittance and a reflectance side of the Fabry-Pérot etalon are detected individually, and intensities of two spectra are divided to increase the visibility by narrowing a spectrum width. Confirmation of an increase in the visibility is conducted by comparing full width half maximum values of spectra obtained by a constructed optical setup, and evaluation accuracies were compared by repeating measurements for 100 times. The output angle using estimated local maxima of the divided spectra is then evaluated to verify the feasibility of the proposed method. As a result, it is confirmed that the proposed method improves the accuracy of angle determination by one order of magnitude.

Mechanism of crescent-shaped and ring-shaped epidermal damage from laser hair removal with cryogen spray cooling.

The safety and efficacy of laser hair removal have been well established through many clinical studies and through clinical use over the past 25years. A laser hair removal device that protects the epidermis by utilizing cryogen spray cooling (CSC) is widely used internationally. In darker skin types, post-inflammatory hyperpigmentation (PIH) can occur after laser hair removal. In particular, laser hair removal with CSC is known to cause crescent-shaped or ring-shaped PIH. In this experiment, we report a visualization of this PIH mechanism. The laser used in this experiment is a 755-nm-long-pulsed alexandrite laser. Graph paper was treated with this laser to assess for thermal damage. We investigated changes in thermal damage due to differences in laser spot size, fluence output, and laser beam angle in relation to the graph paper. When using a spot size of 18mm, we observed that higher fluences caused crescent-shaped thermal damage on the margins of the treated graph paper. It was also confirmed that when the hand piece is not held perpendicular to the skin, the laser-treated area is expanded and the CSC range is narrowed. These factors caused the area of thermal damage to widen. This widening causes ring-shaped thermal injury, leading to PIH. We treated graph paper using a hair removal laser with CSC to investigate the mechanism of crescent or ring-shaped thermal damage. Laser treatment on graph paper is effective as a test for defects in the CSC device. Factors that cause inadequate cooling, which leads to PIH, are large spot size, high fluence, not holding the laser hand piece perpendicular to the skin, and malfunctioning of CSC device.

High-Order Compensated Capacitive Power Transfer Systems With Misalignment Insensitive Resonance

A well-performed capacitive power transfer (CPT) system highly depends on its compensation to achieve load-independent (LI) output and zero phase angle (ZPA) operation. It is particularly meaningful to maintain these objectives under various misalignments. This paper is devoted to a general and comprehensive method to study and explore all the potential high-order compensations. The coupler parameter variation is evaluated under different types of misalignment, and misalignment-insensitive (MI) parameters are properly designed for MI resonance. A general and straightforward decomposition and synthesis method is then proposed to generate the high-order resonant tanks. With the help of inverse ABCD parameters, all tank candidates are further judged by their capability for LI output and ZPA operation. Finally, two example CPT systems are built to verify the LI output and ZPA operation under misalignment.

A lightweight bending actuator based on shape memory alloy and application to gripper

The shape memory alloy (SMA) material is embedded into elastic material to make the bending actuator through the shrinkage property of SMA material during being heated. This production method is with the characteristics of long production time and cumbersome making process. As the SMA material is embedded in the elastic actuator, the heat dissipation with the environment is slow, resulting in low actuating efficiency. In this article, a new lightweight bending actuator is developed based on pre-bent SMA wire. The SMA wire is used as the body and actuator, and realizes the initial shape recovery through active control mode instead of relying on heat exchange only. The manufacturing process of the bending actuator is very simple and low-price. The pre-bent angle of SMA wire can be programmed to control the actuator's output angle. By modeling the phase transformation process of SMA wire, the change in Young's modulus at different temperatures is analyzed, and the actuating current and pre-bent angle of SMA wire are calculated. Based on the changing resistance of SMA wire during being heated, the strategy to avoid overheating is designed and achieved. Imitated the form of human hand grasping, a lightweight gripper with palm function is made, and four grasping strategies are designed for the gripper and tested. Finally, the gripper is tested on the continuum arm made of pre-bent actuator. The actuator broadens the application form of SMA wire actuated actuator and provides a new method for designing lightweight and miniaturized soft gripper.

Capacitive Power Transfer With Series-Parallel Compensation for Step-Up Voltage Output

In this article, a basic capacitive power transfer topology with series-parallel compensation is developed for load-independent step-up voltage output. There are three main contributions. First, the step-up constant-voltage (CV) output and zero-phase angle property are designed by using an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h</i> -parameter modeling method. Second, a current-source rectifier is proposed at the secondary side and the working transient is analyzed. Third, the impact of parasitic resistances is investigated, and the output voltage attenuation and system efficiency are analyzed at different loads, coupling coefficients, and quality factors. A 130-W prototype is implemented with 150 × 300-mm metal plates. Experiments validate the CV output property with a step-up voltage gain of 2. The peak efficiency is 86.6% at a coupling coefficient of 0.16 and a transfer distance of 4 mm.

Research on the Finite Time Compound Control of Continuous Rotary Motor Electro-Hydraulic Servo System

Aiming at the influence of friction, leakage, noise and other nonlinear factors on the performance of the electro-hydraulic servo system of a continuous rotary motor, a finite-time composite controller for the aforementioned servo system is proposed. First, a mathematical model of the electro-hydraulic servo system was analyzed, and the input and output angle data of the motor were collected for system identification. Subsequently, the ARMAX identification model of the continuous rotary motor system was obtained. Then, according to the observed advantages, namely faster capability of the finite-time controller (FTC) to converge the system, and ability of the finite-time observer to reduce the steady-state error of the system, the finite-time controller and finite-time state observer of a continuous rotary electro-hydraulic servo motor were respectively designed. Finally, comparison with PID control simulation shows that the compound controller could effectively improve the control accuracy and performance of the system.

Loss of field of view due to optical mismatch at the inner diametric plane of cylindrical artificial microvessels

In the experimental research with cylindrical artificial microvessels it may not be possible to view the entire inner diameter, due to optical mismatch between the microvessel material and the inside liquid suspension. A quantification of the field of view loss (FOVL) at the inner diametric plane is proposed, when the liquid suspension has a lower refractive index than the microvessel material and imaging is performed by a dry objective lens. A graphical model shows the optical ray tracing, utilizing 3 different refractive indices (η1, η2 and η3) for the microvessel material, the liquid suspension and the air. The numerical aperture (NA) of the objective lens defines the maximum ray output angle received by the lens and corresponds to a certain FOVL. Output angles were estimated for 8 different input angles and the corresponding FOVLs ranged from 71% down to 2%. The graphical model theoretical estimations were assessed experimentally for the cases of a water suspension and a plasma diluted blood sample (5% hematocrit). The theoretical estimations deviated only ±3% from the experimental assessments, showing that the graphical model could be a valuable tool for research on cylindrical artificial microvessels with dry objective lenses.

Where and how Ruppert’s algorithm fails

Several examples are given to demonstrate non-termination of Ruppert’s Delaunay refinement algorithm for triangular mesh generation exploring the relationship between the minimum angle in the input and the minimum allowable angle in the output. These examples show non-termination despite requiring a minimum output angle of less than 30° which is smaller than the value generally observed in practice. For input containing only points, an example demonstrates failure of the algorithm with a minimum angle of 30° showing that the theoretical analysis in that context is sharp.

Design of a fast steering mirror driven by piezoelectric ceramics

To solve the small-optical aperture and stroke problem of existing fast steering mirror (FSM), we focus on the design of FSM driven by piezoelectric ceramics in space laser communication and lidar systems. The structure design of the FSM and the theoretical analysis of the piezoelectric actuators are carried out. The special structure and installation process of the mirror assembly are designed to ensure the accuracy of the mirror surface. Theoretical calculation and simulation analysis are conducted to evaluate the mirror’s output angle. The dynamic model of the FSM is established to analyze the stiffness. The operating principle and characteristic analysis results of FSM are verified by experimental tests. The results show that the FSM can provide a mechanical excursion angle of ±2.35 mrad, the closed-loop linearity of X axis and Y axis are 0.71% and 0.67%, respectively, and the closed-loop bandwidth of the FSM is 28 Hz. The surface shape accuracy of the mirror after installation can reach 1 / 50λ.