Field Control Method Research Articles

A safety-enhanced eco-driving strategy for connected and autonomous vehicles: A hierarchical and distributed framework

This paper presents a safety-enhanced eco-driving strategy for connected and autonomous vehicles (CAVs), which is implemented by a hierarchical and distributed framework. The driving risk field, shockwave theory, and motion planning and control method are integrated into this framework to optimize the trajectories of CAVs on a signalized arterial under mixed traffic flow, with the aim of reducing the driving risk and fuel consumption of CAVs simultaneously, while ensuring traffic efficiency. The optimization procedure is mainly composed of two parts: long-term trajectory planning based on optimal control and short-term trajectory control based on model predictive control, which makes the strategy more adaptable to the various traffic conditions. The results show that the proposed framework can effectively reduce the safety risk that vehicles are exposed to and their fuel consumption by 18%–24% and 20%–27%, respectively. Furthermore, it reveals that conventional eco-driving strategies may result in negative safety issues when only considering the impact of preceding vehicles on the eco-CAV. However, these negative impacts can be eliminated when the impacts of following vehicles on the eco-CAV are taken into account. In addition, the sensitivity analysis on the Market Penetration Rate (MPR) of CAVs and traffic demand is performed. The results show that the framework is robust and can work under various traffic conditions (including under-saturated and over-saturated ones) and different MPRs.

Amplitude Matching for Multizone Sound Field Control

A multizone sound field control method, called amplitude matching, is proposed. The objective of amplitude matching is to synthesize a desired amplitude (or magnitude) distribution over a target region with multiple loudspeakers, whereas the phase distribution is arbitrary. Most of the current multizone sound field control methods are intended to synthesize a specific sound field including phase or to control acoustic potential energy inside the target region. In amplitude matching, a specific desired amplitude distribution can be set, ignoring sound propagation directions. Although the optimization problem of amplitude matching does not have a closed-form solution, our proposed algorithm based on the alternating direction method of multipliers (ADMM) allows us to accurately and efficiently synthesize the desired amplitude distribution. We also introduce the differential-norm penalty for a time-domain filter design with a small filter length. The experimental results indicated that the proposed method outperforms current multizone sound field control methods in terms of accuracy of the synthesized amplitude distribution.

Rapid construction of safe-zone by active flow field control and sparse-sampling-perception-network for public indoor environments suffering from nerve agents

Nerve agents' attacks in public indoor environments significantly threaten citizens' health. The pattern control of nerve agents is pivotal in efficiently decontaminating and rescuing. We propose an intelligent system that constructs safe zones rapidly for people to take refuge through active flow field control and a sparse-sampling perception network (SSPN). In this work, A 336*206*46.5 m large-scale indoor space, modeling a meeting hall suffering from nerve agents, has been utilized as a typical scenario to simulate the decontamination and safe zone construction process: (1) Firstly, numerous kinds of distribution patterns are constructed by active flow field control method. (2) Secondly, 100 real-world scenarios are simulated based on the computational fluid dynamic (CFD) methods and verified by PIV experiments. (3) Thirdly, a sparse-sampling perception network is proposed to perceive the concentration distribution of nerve agents in the whole space under limited local samplings. (4) Fourth, the decontamination and safe zone construction strategy is dynamically adjusted according to the perceived distribution. Extensive experiments are conducted, and the results show that our SSPN achieves the highest accuracy among all algorithms proposed in the article. The RMSE and MARE between predicted and actual results are less than 0.5 and 0.8, and the fitted curve for SPNN is closest to the curve y = x, indicating the model's accuracy and robustness. Furthermore, the safe zone can be constructed within 25 s, and the rescue routes can be designed efficiently. We provide an innovative and efficient rescue reference for public indoor environments suffering from nerve agents.

Multi-UAV cooperative target encirclement within an annular virtual tube

Continuously encircling and monitoring an individual static target is an important application scenario for a multi-UAV system. In this paper, to address the problem of multi-UAV encircling the target arbitrarily, evenly and densely in 3D space, a distributed vector field control method with an annular virtual tube is proposed. Some Lyapunov-like functions are designed elaborately, and a formal analysis based on the invariant set theorem is made to show that all UAVs can complete the encirclement task successfully. Simulations and experiments are carried out to show the effectiveness of the proposed method.

Optimized magnetic field control of an electromagnetic actuation system for enhanced microrobot manipulation

This paper presents a novel magnetic field control method to enhance the performance in terms of accuracy and field strength of underdetermined electromagnetic actuation systems. Conventional control algorithms prioritize low overall power usage, and they fail to cope with the saturation of electromagnets due to a limited power supply, which limits the magnetic and gradient field strength of a system. In this study, we prioritize magnetic and gradient fields, among other priorities, by developing computational optimization programming to find alternative solutions that satisfy constraints. Single- and multi-objective optimization techniques are developed and compared to address the problem. The latter algorithm, which employs the weighted sum method to obtain Pareto-optimal solutions, demonstrates better performance than the former one. The proposed control methodology is characterized and validated by simulation and experiments. The maximum magnetic and gradient fields were significantly enhanced by the proposed algorithm; by approximately 35% and 70%, respectively, compared to the conventional independent control applied for our system and by 24% and 64%, respectively, for a benchmark system.

Scaling of voltage controlled magnetic anisotropy based skyrmion memory and its neuromorphic application

Voltage controlled skyrmion memory requires less energy compared to current controlled method where voltage changes magnetic anisotropy (VCMA) and Dzyaloshinskii-Moriya interaction (DMI). Ferromagnetic (FM) and synthetic antiferromagnetic (SAFM) memory devices are simulated using electric field control method where gate and gap width are chosen as smaller than skyrmion size so that skyrmion can feel the change in voltage polarity in the neighbouring gate and moves accordingly. Scaling of memory device is performed which shows SAFM memory can be made much narrower compared to FM memory as skyrmion diameter also depends on width of the structure. Effects of device structure and skyrmion-skyrmion repulsion force on skyrmion diameter variation are shown in cylindrical structure considering effect of demagnetizing field. Apart from these, neuromorphic application is considered where skyrmion moves from central square neuron region to surrounding synapse region or vice versa by the application of voltage. Switching time, voltage range, energy and scaling of device dimensions are shown for synapse-neuron having different number of skyrmions where multiple skyrmions represent different weight in the neuromorphic circuit.

Independent Electromagnetic Field Control for Practical Approach to Actively Locomotive Wireless Capsule Endoscope

Toward wireless medical microrobot applications driven by an electromagnetic actuation (EMA) system, challenges associated with movability, the electromagnetic force, and the coil system size must be addressed. This paper presents an enhanced EMA system with a higher magnetic field via new coil configurations, an independent magnetic field control method, and application to the multi-degree-of-freedom (DOF) motion of an untethered capsule endoscope. The magnetically actuated capsule endoscope (MACE) system proposed herein consists of an endoscopic capsule with a permanent magnet in the body, eight air-cored stationary electromagnetic coils, and a control system. The coil system is designed to maximize the working space available within a limited equipment space. The MACE is designed to perform full 5-DOF motion, including 3-DOF translation and 2-DOF rotation. The independent magnetic field control method with the new coil configuration enables orientation-independent-driving (OID) control of the capsule endoscope that could not be accomplished by previous EMA systems. The developed system performance was verified by simulations and experiments. The MACE motion in the spatial domain was evaluated with a robotic endoscopic procedure and diagnostic performance by in-vitro and ex-vivo experiments.

Low-valence titanium oxides synthesized by electric field control as novel conversion anodes for high performance sodium-ion batteries

The low-valence titanium oxides (TiO, Ti2O) were synthesized by electric field control method. The multi-electron redox reactions and fast charge transfer kinetics result in the excellent Na storage performances of low-valence titanium oxides.

Modeling And Design Of Nano Scale Cmos Controller Using Adaptive Neuro-Fuzzy For Speed Control Of Dc Shunt Motor

The main aim of this work is to control the speed of the DC shunt motor by using a nano scale Complimentary Metallic oxide Field Effect Transistor (CMOS) inverter with Adaptive Neuro-Fuzzy based method for optimal parameter selection. The speed of the DC shunt motor can be varied by varying armature voltage with field current constant and varying the field current with armature voltage constant. It is found that the speed is said to increase with increase in armature voltage for which the graph is a linear in case of armature controlled method. Whereas for the field control method the speed is said to increase with decrease in field current with armature voltage to be constant. The stated condition is cross verified by plotting the graphs for conventional and proposed nano scale CMOS inverter with ANFIS optimization scheme. A novel technique for modeling and devising a nano scale CMOS circuit using adaptive neuro-fuzzy network for controlling and tuning the switching characteristics of the circuit so that it is symmetric with equal values of rise time and fall time with equal output for propagation delay during low to high and high to low outputs. This control over the CMOS switching characteristics using ANFIS controller offers an effective speed control for DC shunt motors. The designed scheme for 45nm process technology is simulated using MATLAB. The results for nano scale CMOS inverter with ANFIS optimization scheme proved to be accurate with an accuracy of 97.5% to 100% which is compared with experimentation results obtained in laboratory using conventional speed control techniques like field and armature control methods.

Fundamental study on the magnetic field control method using multiple HTS coils for Magnetic Drug Delivery System

The magnetic drug delivery system (MDDS) is a key technology to reduce the side effects in the medical applications, and the magnetic force control is very important issue in MDDS. In this application, the strength of magnetic field and gradient required to MDDS devices are 54 mT and 5.5 T/m, respectively. We proposed the new magnetic force control system that consists of the multiple racetrack HTS magnets. We can control the magnetic field gradient along the longitudinal direction by the arrangement of the multiple racetrack HTS magnets and operating current of each magnet. When the racetrack HTS magnets were used, the critical current was reduced by the self-magnetic field. Therefore, the shape design of HTS magnet to reduce the magnet field into the surface of HTS tapes was required. Therefore, the electromagnetic analysis based on finite element method (FEM) was carried out to design and optimize the shape of multiple racetrack HTS magnet. We were able to suppress the reduction of critical current by placing the magnetic substance at upper and lower side of the HTS magnets. It was confirmed that obtained maximum values of magnetic field strength and field gradient were 33 mT and 0.18 T/m, respectively.

Development of Field Control Method and Basic Design of HTS Magnet for MDDS

The magnetic drug delivery system (MDDS) is a key technology to reduce the side effects in the medical applications. We proposed the new magnetic force control system that consists of superconducting magnet, high temperature superconductors (HTS) tapes and iron blocks. In this study, it was confirmed that the control of magnetic field gradient was possible by arranging the HTS tapes and iron blocks on the superconducting magnet. In addition, the multiple racetrack HTS magnets were proposed in order to generate the high field gradient along the longitudinal direction.

A simple and rapid one-time method to evaluate the non-acidic gas content from bioprocesses

This paper presents a rapid less than 2 min and low-cost method involving the use of alkali solution to capture the acidic gasses from a biogas, thereby providing an estimate of the percentage of non-acidic gasses. Such a method was mentioned in the literature but never fully described or optimized. After sampling an aliquot of gas from bioprocess, gas was injected in a sealed flask with a 3 M NaOH solution, and after equilibrium was obtained, the non-acidic gas volume was measured. The method was first calibrated with certified gasses with an accuracy observed between 98 and 105%. Regarding the validation step, certified standard gas mixtures and nine biogas-laboratory batch reactors were used, the overall accuracy reported was 103 + 3%. This rapid and low-cost method may either be used in laboratory conditions as a quick and low cost alternative to standard analysis equipment or in addition as a routine field control method used on full-scale plants.

Study on Navigation of Wireless Sensor Network Mobile Robot

For optimal design of mobile robot path planning problem, an improved artificial potential field control method is designed. Using infrared sensors and ultrasonic sensors to detect the surrounding environment will get the information of obstacles and goals. Proposed an adaptive real-time localization algorithm based on improved DV-Hop algorithm to realize real-time localization for wireless sensor network mobile robot. The improved artificial potential field adopted the improved potential function that ensured the goal is the global minimum so the mobile robot can reach the goal freely. The effectiveness and feasibility of the improved algorithm verified by simulation.

Performance Analysis and Dynamic Characteristics of Hysteresis-Based Indirect Field-Oriented Control of Induction Motordrives

In this paper, the dynamic properties of an induction motor drive using an indirect field control method (IFCM) with a constant frequency hysteresis current controller (CFHCC) are discussed. A comparison between space vector modulation techniques with proportional integral (PI) controller or with a CFHCC is then done. In the first place, the paper presents a theoretical analysis of the whole system consisting of an induction motor with a frequency converter, the principles of scalar and vector control methods.The stability analysis and optimal performance of the proposed control scheme with CFHCC under no-load conditions or mechanical load disturbances and parameter uncertainties are also discussed via experimental and simulation examples. The effect of setting the range of the modulation frequency on these different load curves is also explained.Finally, the advantages of using the IFCM with the hysteresis current controller as compared to the IFCM with a classic PI controller are mentioned.

Improvement of Hydro-cyclone Performance by Use of Local Electrostatic Potential Field and Fluid Flow Control Method

Experimental studies have been carried out about improvement of hydro-cyclone performance by use of local electrostatic field and fluid flow control method in the upper plate. By use of the local electrostatic field applied in the under-flow section, with the center lod as a negative electrode and the outer wall as a positive electrode, the particle separation performance was improved.By use of pre-treatment of feed slurry mixing in electrostatic potential field, particle separation performance increased with the increase of absolute value of negative zeta potential. The partial separation efficiency increased in case of the special ring attached on the upper plate in order to improve particle separation performance. The optimum angle of the special ring was found from the experimental data. By use of the proposed methods, the separation efficiency of particle is increased and the proposed new methods may be effective in practical separation process.

Development of MR Compatible Manipulandum for Finger Movements

Magnetically compatible robots are required as haptic interfaces for neuroscience studies. The purpose of this paper is to develop an MR compatible robot using ultrasonic motor, which is able to work within an MRI/fMRI scanner and to acquire MRI images continuously during finger motions. In addition, the force field control method of ultrasonic motor is discussed. The characteristic of voltage phase and motor torque is investigated experimentally, and these results are used for the force field control of ultrasonic motors. The position dependent force fields and velocity dependent force fields are evaluated with a force sensor. Also, MR compatibility is verified experimentally. Finally, some brain activities are investigated with fMRI during finger movements.

High-rate flame synthesis of vertically aligned carbon nanotubes using electric field control

The electric field controlled synthesis of carbon nanomaterials on a Ni-based catalytic support positioned at the fuel side of the opposed flow oxy-flame is studied experimentally. Carbon nanomaterials formed on the probe surface are comparatively analyzed for two characteristic operational modes: a grounded probe mode and a floating probe mode. In a grounded mode a number of various carbon nanostructures are formed depending on the probe location in flame. Observed nanoforms include multi-walled carbon nanotubes (MWNTs), MWNT bundles, helically coiled tubular nanofibers, and ribbon-like coiled nanofibers with rectangular cross-section. The presence of various carbon nanoforms is attributed to the space variation of flame parameters, namely flame temperature and concentration of chemical species. It is found that the presence of an electric potential (floating mode operation) provides the ability to control the nanostructure morphology and synthesis rate. A thick layer (35–40 μm) of vertically aligned carbon nanotubes (VACNTs) is found to be formed on the probe surface in the floating potential mode. This layer is characterized by high uniformity and narrow distribution of nanotube diameters. Overall, the electric field control method demonstrates stabilization of the structure in a wide flame region while growth rate remains dependent on flame location.

Effect of bootstrap current on MHD equilibrium beta limit in heliotron plasmas

The effect of bootstrap current on the beta limit of MHD equilibria is studied systematically byan iterative calculation of MHD equilibrium and the consistent bootstrap current in high betaheliotron plasmas. The LHD machine is treated as a standardconfiguration heliotron with an L = 2 planar axis. The effects of vacuum magneticconfigurations, pressure profiles and the vertical field control method are studied. Theequilibrium beta limit with consistent bootstrap current is quite sensitive to the magnetic axislocation for finite beta, compared with the currentless cases. For a vacuum configuration withthe magnetic axis shifted inwards in the torus, even in the high beta regimes, the bootstrap currentflows to increase the rotational transform, leading to an increase in the equilibrium beta limit. Onthe contrary, for a vacuum configuration with the magnetic axis shifted outwards in the torus, even inthe low beta regimes, the bootstrap current flows so as to reduce the rotational transform;therefore, there is an acceleration of the Shafranov shift increase as beta increases, leading to adecrease in the equilibrium beta limit. The pressure profiles and vertical field controlmethods influence the equilibrium beta limit through the location of the magnetic axis for finite beta.These characteristics are independent of both device parameters, such as magnetic fieldstrength, and device size in the low collisional regime.

Field Trial for the Control of Zoonotic Cutaneous Leishmaniosis in Badrood, Iran

Due to the resurgence of zoonotic cutaneous leishmaniosis (ZCL) in some nonendemic areas of Iran, extensive studies have been conducted on the epidemiology of the disease in different parts of the country in recent years. The objective of this study was to determine the effects of rodent control on the reduction of the incidence of ZCL in an endemic area in Badrood, Iran. A survey was carried out in a circle around two villages between April 1997 and January 1999. The control strategy adopted in 1997 consisted of the destruction of the colonies of gerbilline rodents by digging in a radius of 500 m from houses in the intervention area. Opened burrows were baited with zinc phosphide. One village was used as control. Evaluation was made in 1998 and no other control measures were carried out in the area. Case findings were done by house-to-house visits once every season during 1997 and 1998, and all the inhabitants of the selected villages were examined. The average reduction of rodent holes was calculated at 87.4% one year after the first baiting in the intervention area. Changes in the number of rodent holes and the incidence of the disease in the intervention and control villages were statistically significant (P-value <0.000001). Our evaluation demonstrated that the control program reduced the incidence of ZCL 12-fold in the treated village compared to the control at the end of the first year of operation, and to more than one-fifth of its original level after two years. The results show that the field control method is very effective in destroying rodents and reducing the incidence of ZCL on a small scale and in special circumstances.

Study of Active Sound Field Control Using Analysis of Structural-Acoustic Coupled System.

The active sound field control is effective for low frequency range and the control in an enclosed cavity is more effective by using the sound pressure data at many measureing points. It is, however hard to set many sensors in the enclosed cavity because of the lack of space or cost problem. In this paper, a new active sound field control method is proposed, where the unknown inner sound pressures are estimated by using the structural acoustic coupled analysis method. In this method, the number of measuring points of sound pressure can be imaginarily increased. As the numerical example, the rectangular prism model is taken up, and the active sound field control in the model in simulated by using the proposed method. As the result, it is shown that the proposed method is effective in the numerical simulation.