Bidirectional Control Research Articles

Flossing DNA in a Dual Nanopore Device.

Solid-state nanopores are a single-molecule technique that can provide access to biomolecular information that is otherwise masked by ensemble averaging. A promising application uses pores and barcoding chemistries to map molecular motifs along single DNA molecules. Despite recent research breakthroughs, however, it remains challenging to overcome molecular noise to fully exploit single-molecule data. Here, an active control technique termed "flossing" that uses a dual nanopore device is presented to trap a proteintagged DNA molecule and up to 100's of back-and-forth electrical scans of the molecule are performed in a few seconds. The protein motifs bound to 48.5 kb λ-DNA are used as detectable features for active triggering of the bidirectional control. Molecular noise is suppressed by averaging the multiscan data to produce averaged intertag distance estimates that are comparable to their known values. Since nanopore feature-mapping applications require DNA linearization when passing through the pore, a key advantage of flossing is that trans-pore linearization is increased to >98% by the second scan, compared to 35% for single nanopore passage of the same set of molecules. In concert with barcoding methods, the dual-pore flossing technique could enable genome mapping and structural variation applications, or mapping loci of epigenetic relevance.

Implementation of Controller for PMBLDC Motor Drive based Electric Vehicle

The entire research community working on automobiles have turned their focus on electric vehicle. PMBLDC motor is very popular in industrial and household applications due to its high efficiency, high power density and low maintenance cost. The rapid advancement in power electronics devices and controllers aids the use of PMBLDC motor in electrical drives system instead of conventional DC motor and AC motor. In this paper we have discussed a Simulink model of Bi-directional speed control for high torque to volume ratio PMBLDC motor to control the speed of PMBLDC motor in electric vehicle application. In this scheme the direction of motor is changed only with change in switching pattern. So this method is a cost effective method. The same strategy has been implemented using DSPIC4011, 16 bit microcontroller. The Raspberry Pi acts as a gateway to configure the unique ID for the application and connect it with the web server. The device is capable of sending the sensor value to the database and the user can able to monitor the value in the web page.

Bidirectional Control of Myoelectric Prostheses in Upper Limb Amputees: Current Results and Expectations

Abstract The most common causes of upper-limb amputations include traumatic etiology and malignity, followed by peripheral vascular diseases. Prosthetic fitting along with conducting a rehabilitation program provide the greatest possible degree of independence to the upper-limb amputees in performing their daily tasks, occupational, recreational and work activities. Despite recent advance in strategies of design and control, the lack of sensory feedback is, according to patients, one of the most important characteristics lacked by commercial myoelectric prostheses. This reason has led to the need for the development of comprehensive prosthetic part which would provide intuitive control and realistic sensory feedback to the amputees enabling them thus to more easily accomplish the tasks which are essential for easier performance of activities of daily life. Electromyography, and recently, electroneurography signals have been used for the development of more efficacious upper-limb prosthetic control. Several recent studies have demonstrated the efficacy of homologous and somatotopic approach in upper-limb amputees, by applying implanted and surface electrodes. This work presents novel methods for effective bidirectional control of myoelectric prostheses in patients with upper-limb amputations using motor control and sensory feedback. The above-mentioned approaches are applicable and have good prospects in further clinical use. The intraneural, extraneural and surface approach can be more or less applicable depending on the etiology and the level of amputation. From a clinical point of view, various approaches should be combined for obtaining more efficient control of bidirectional prostheses and corresponding sensory feedback.

Orthopaedic Osseointegration: State of the Art.

Osseointegration is a surgical approach that permitted the direct attachment of an external prosthesis to the skeleton in some select patients with amputation, who had failed to tolerate conventional sockets, thereby obviating related issues such as discomfort, skin breakdown, and poor fit. In this specific population, osseointegration offers the potential for enhanced biomechanical advantage and rehabilitative potential. Multiple percutaneous implant systems exist for clinical use internationally, each attempting to create a stable bone-implant interface while avoiding complications such as infection and loosening. Prospective clinical trials are now underway in the United States. This article will review the history and biology of osseointegration, indications and contraindications for use of currently available implant systems, and reported outcomes. Future directions of orthopaedic osseointegration technology, including electronic systems capable of biomimetic bidirectional volitional motor control of, and sensory/proprioceptive feedback from, external prosthetic devices, will also be discussed.

Comparison of matrix converter stabilisation techniques based on the damping resistor and digital filter approaches for bidirectional power flow control

The matrix converter is becoming a mature technology with its specific advantages and limitations and can be effectively used as interface link in the future smart grids. In this context, the stability of the converter under different power flow conditions is highly important and needs more clarification. The input inductor-capacitor filter can significantly impact the stability of the converter when the output is tightly regulated, especially in bidirectional power flow control applications where a low-impedance source is connected to the converter output. This study investigates the matrix converter stability for bidirectional power flow control, considering the input filter and other parameters of the system. A detailed analysis of two commonly used active and passive stabilisation techniques known as digital filter and damping resistor approaches is presented, and a combination of these two methods is suggested as a better choice. The converter stability region for the proposed technique is determined by using the small-signal model of the converter. The converter performance for the methods is compared in terms of the efficiency, stability, transients, and quality of the input and output currents. Numerical simulations and experimental tests are conducted on a prototype direct matrix converter to validate the proposed method.

Islanded distributed generation system with feedforward PR‐EFLL control for AC‐electric vehicle charger

This study deals with the islanded distributed generation system (IDGS), which is used to feed different types of loads such as AC-EVs (electric vehicles) and non-linear home load. The IDGS consists of solar photovoltaic (PV) array with a storage battery. In IDGS feeding, the EVs and non-linear load, the currents contain high harmonics. Due to which, the generation of sinusoidal voltage with good quality at common coupling point (CCP) is very challenging. Therefore, a feedforward proportional resonant (PR) controller is proposed with enhanced frequency locked loop (EFLL) control algorithm to eliminate the CCP voltage harmonics and provides the high tracking capability of AC voltage as compared to the conventional proportional integral (PI) control. As a result, the voltage source converter control generates the balanced and sinusoidal CCP voltages even at unbalanced load condition. The proposed EFLL-based control algorithm is capable to reject the DC-offset component from the load current. Moreover, the DC-link voltage regulation and peak power extraction of solar-PV array are achieved through bidirectional DC-DC converter control. This BDC control is used to balance the active power flow in the islanded system. The effectiveness of the proposed IDGS is validated, through simulation as well as experimental steady-state and dynamic test results.

Bidirectional Power Flow Control in AC/DC Hybrid System under AC and DC Fault Conditions

This paper presents a hybrid AC-DC microgrid to reduce the process of multiple conversions in an individual AC microgrid or DC microgrid. The proposed hybrid microgrid compose of both AC microgrid and DC microgrid connected together by bidirectional interlink converter (BIC). Utility grid, 150kVA diesel generator (DG) and 100kW AC load are connected in AC microgrid. DC microgrid is composed of 100 kW photovoltaic array (PV), 20kW battery energy storage system (BESS) and 20kW DC load. The droop control technique is applied to control the system for power sharing within the sources in AC/DC hybrid microgrid in proportion to the power rating. When the faults occur at AC bus, protection signal applied to breaker for isolating the healthy and faults system. DC faults occur at DC bus, DC breaker isolate the AC and DC bus. The system performance for power flow sharing on hybrid AC-DC microgrid is demonstrated by using MATLAB/SIMULINK.

Dual and Opposing Functions of the Central Amygdala in the Modulation of Pain

SUMMARYPain perception is essential for survival and can be amplified or suppressed by expectations, experiences, and context. The neural mechanisms underlying bidirectional modulation of pain remain largely unknown. Here, we demonstrate that the central nucleus of the amygdala (CeA) functions as a pain rheostat, decreasing or increasing pain-related behaviors in mice. This dual and opposing function of the CeA is encoded by opposing changes in the excitability of two distinct subpopulations of GABAergic neurons that receive excitatory inputs from the parabrachial nucleus (PB). Thus, cells expressing protein kinase C-delta (CeA-PKCδ) are sensitized by nerve injury and increase pain-related responses. In contrast, cells expressing somatostatin (CeA-Som) are inhibited by nerve injury and their activity drives antinociception. Together, these results demonstrate that the CeA can amplify or suppress pain in a cell-type-specific manner, uncovering a previously unknown mechanism underlying bidirectional control of pain in the brain.

Bidirectional Power Flow Control of a Multi Input Converter for Energy Storage System

The objective of this paper is to propose a multi-input DC-DC converter with bidirectional power flow control capability. Compared to the traditional power converter, the multi-input converter (MIC) can save on the number of components and the circuit cost. Under normal conditions, the MIC is able to transfer energy from different input sources to the load. However, if the battery module is adopted, both the charging or discharging features should be considered. Therefore, the bidirectional power flow control of the MIC is necessary. On the other hand, because of the inconsistency characteristics of batteries, unbalanced circuit operation might occur whereby the circuit and the battery might be damaged. Therefore, dynamic current regulation strategies are developed for the MIC. Consequently, the proposed MIC circuit is able to achieve the bidirectional power flow control capability as well as control the input currents independently. Detailed circuit analysis and comprehensive mathematical derivation and of the proposed MIC will be presented in this paper. Finally, both simulation and experimental results obtained from a 500 W prototype circuit verify the performance and feasibility of the proposed bidirectional multi-input converter.

Cannabidiol Counteracts the Psychotropic Side-Effects of Δ-9-Tetrahydrocannabinol in the Ventral Hippocampus through Bidirectional Control of ERK1-2 Phosphorylation.

Evidence suggests that the phytocannabinoids Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) differentially regulate salience attribution and psychiatric risk. The ventral hippocampus (vHipp) relays emotional salience via control of dopamine (DA) neuronal activity states, which are dysregulated in psychosis and schizophrenia. Using in vivo electrophysiology in male Sprague Dawley rats, we demonstrate that intra-vHipp THC strongly increases ventral tegmental area (VTA) DA neuronal frequency and bursting rates, decreases GABA frequency, and amplifies VTA beta, gamma and ε oscillatory magnitudes via modulation of local extracellular signal-regulated kinase phosphorylation (pERK1-2). Remarkably, whereas intra-vHipp THC also potentiates salience attribution in morphine place-preference and fear conditioning assays, CBD coadministration reverses these changes by downregulating pERK1-2 signaling, as pharmacological reactivation of pERK1-2 blocked the inhibitory properties of CBD. These results identify vHipp pERK1-2 signaling as a critical neural nexus point mediating THC-induced affective disturbances and suggest a potential mechanism by which CBD may counteract the psychotomimetic and psychotropic side effects of THC.SIGNIFICANCE STATEMENT Strains of marijuana with high levels of delta-9-tetrahydrocannabinol (THC) and low levels of cannabidiol (CBD) have been shown to underlie neuropsychiatric risks associated with high-potency cannabis use. However, the mechanisms by which CBD mitigates the side effects of THC have not been identified. We demonstrate that THC induces cognitive and affective abnormalities resembling neuropsychiatric symptoms directly in the hippocampus, while dysregulating dopamine activity states and amplifying oscillatory frequencies in the ventral tegmental area via modulation of the extracellular signal-regulated kinase (ERK) signaling pathway. In contrast, CBD coadministration blocked THC-induced ERK phosphorylation, and prevented THC-induced behavioral and neural abnormalities. These findings identify a novel molecular mechanism that may account for how CBD functionally mitigates the neuropsychiatric side effects of THC.

A New Relieving-DC-Saturation Hybrid Excitation Vernier Machine for HEV Starter Generator Application

Benefiting from flexible flux control and short-circuit withstand ability, the hybrid excitation machine is an emerging starter generator solution for hybrid electric vehicle propulsion. However, to realize a brushless hybrid design in conventional permanent magnet machines, a three-dimensional magnetic circuit is usually adopted, leading to complicated mechanical structure and torque density sacrifice. To address this issue, a new relieving-dc-saturation hybrid excitation Vernier machine is proposed in this article, which integrates good torque density and bidirectional flux control within a simple and brushless structure. The key is to artificially construct reluctance effect in a consequent-pole Vernier permanent magnet machine (CP-VPMM) by introducing extra dc field excitation equipped with the relieving-dc-saturation ability. In this way, the advantages of bidirectional flux control in stator-dc-excited reluctance machine and good torque density in CP-VPMM are well combined in this topology, making it especially suitable for multimode starter generator application. In this article, the machine structure and its design mechanism are introduced, with its electromagnetic performance evaluated by the finite-element simulation. A prototype is manufactured and tested. Experiment results verify the feasibility of this new topology.

Heat flux direction controlled by power-law oscillators under non-Gaussian fluctuations.

Chains of particles coupled through anharmonic interactions and subject to non-Gaussian baths can exhibit paradoxical outcomes such as heat currents flowing from colder to hotter reservoirs. Aiming to explore the role of generic nonharmonicities in mediating the contributions of non-Gaussian fluctuations to the direction of heat propagation, we consider a chain of power-law oscillators, with interaction potential V(x)∝|x|^{α}, subject to Gaussian and Poissonian baths at its ends. Performing numerical simulations and addressing heuristic considerations, we show that a deformable potential has bidirectional control over heat flux.

Guided Motion Planning for Snake-like Robots Based on Geometry Mechanics and HJB Equation

In this paper, a novel guided motion planning method is proposed for snake-like robots, which decomposes the configuration space into the fiber space and the gait space, with the motion planned in the low-dimensional fiber space, so as to avoid the dimensionality curse problem. More specifically, first, based on geometry mechanics, the kinematic connection is derived, which successfully maps the motion in the fiber space into that in the gait space. According to the kinematic connection, a novel bidirectional motion control method for snake-like robots is proposed to improve the flexibility that can produce not only the forward locomotion but also the backward locomotion additionally. The convergence of the bidirectional motion control method is proved based on averaging theory. Then, the motion planning problem is solved in the low-dimensional fiber space, for which the HJB equation is used to generate the optimal control in the fiber space to avoid the well-known curse of dimensionality. Finally, combining the bidirectional motion control and the motion planned in the fiber space, a guided motion planning method in the configuration space is proposed. Numerical simulations and experiments based on the real snake-like robot platform are performed, whose results demonstrate that the proposed algorithm is valid and robust.

Grid Interactive Solar PV-Based Water Pumping Using BLDC Motor Drive

This paper proposes bidirectional power flow control of a grid interactive solar photovoltaic (PV)-fed water pumping system. A brushless DC (BLDC) motor drive without phase current sensors is used to run a water pump. This system enables a consumer to operate the water pump at its full capacity for 24 hours regardless of the climatic condition and to feed a single-phase utility grid when water pumping is not required. The full utilization of a PV array and motor pump is made possible in addition to an enhanced reliability of the pumping system. A single-phase voltage source converter with a unit vector template generation technique accomplishes a bidirectional power flow control between the grid and the dc bus of the voltage source inverter (VSI), which feeds a BLDC motor. The VSI is operated at fundamental frequency, which minimizes the switching loss. The maximum power point operation of a PV array, and power quality improvements, such as power factor correction and reduction of total harmonic distortion of grid, are achieved in this system. Its applicability and reliability are demonstrated by various simulated results using MATLAB/Simulink platform and hardware implementation.

Information processing by endoplasmic reticulum stress sensors.

The unfolded protein response (UPR) is a collection of cellular feedback mechanisms that seek to maintain protein folding homeostasis in the endoplasmic reticulum (ER). When the ER is 'stressed', through either high protein folding demand or undersupply of chaperones and foldases, stress sensing proteins in the ER membrane initiate the UPR. Recently, experiments have indicated that these signalling molecules detect stress by being both sequestered by free chaperones and activated by free unfolded proteins. However, it remains unclear what advantage this bidirectional sensor control offers stressed cells. Here, we show that combining positive regulation of sensor activity by unfolded proteins with negative regulation by chaperones allows the sensor to make a more informative measurement of ER stress. The increase in the information capacity of the combined sensing mechanism stems from stretching of the active range of the sensor, at the cost of increased uncertainty due to the integration of multiple signals. These results provide a possible rationale for the evolution of the observed stress-sensing mechanism.

A Contention-Based Hop-By-Hop Bidirectional Congestion Control Algorithm for Ad-Hoc Networks.

Existing hop-by-hop congestion control algorithms are mainly divided into two categories: those improving the sending rate and those suppressing the receiving rate. However, these congestion control algorithms have problems with validity and limitations. It is likely that the network will be paralyzed due to the unreasonable method of mitigating congestion. In this paper, we present a contention-based hop-by-hop bidirectional congestion control algorithm (HBCC). This algorithm uses the congestion detection method with queue length as a parameter. By detecting the queue length of the current node and the next hop node, the congestion conditions can be divided into the following four categories: 0–0, 0–1, 1–0, 1–1 (0 means no congestion, 1 means congestion). When at least one of the two nodes is congested, the HBCC algorithm adaptively adjusts the contention window of the current node, which can change the priority of the current node to access the channel. In this way, the buffer queue length of the congested node is reduced. When the congestion condition is 1–1, the hop-by-hop priority congestion control (HPCC) method proposed in this paper is used. This algorithm adaptively changes the adjustment degree of the current node competition window and improves the priority of congestion processing of the next hop node. The NS2 simulation shows that by using the HBCC algorithm, when compared with distributed coordination function (DCF) without congestion control, the proposed unidirectional congestion control algorithms hop-by-hop receiving-based congestion control (HRCC) and hop-by-hop sending-based congestion control (HSCC), and the existing congestion control algorithm congestion alleviation—MAC (CA-MAC), the average saturation throughput increased by approximately 90%, 62%, 12%, and 62%, respectively, and the buffer overflow loss ratio reduced by approximately 80%, 79%, 44%, and 79%.

A Bidirectional Power Charging Control Strategy for Plug-in Hybrid Electric Vehicles

Plug-in Hybrid Electric Vehicles (PHEVs) have the potential of providing frequency regulation due to the adjustment of power charging. Based on the stochastic nature of the daily mileage and the arrival and departure time of Electric Vehicles (EVs), a precise bidirectional charging control strategy of plug-in hybrid electric vehicles by considering the State of Charge (SoC) of the batteries and simultaneous voltage and frequency regulation is presented in this paper. The proposed strategy can control the batteries charge which are connected to the grid, and simultaneously regulate the voltage and frequency of the power grid during the charging time based on the available power when different events occur over a 24-h period. The simulation results prove the validity of the proposed control strategy in coordinating plug-in hybrid electric vehicles aggregations and its significant contribution to the peak reduction, as well as power quality improvement. The case study in this paper consists of detailed models of Distributed Energy Resources (DERs), diesel generator and wind farm, a generic aggregation of EVs with various charging profiles, and different loads. The test system is simulated and analyzed in MATLAB/SIMULINK software.

Research on battery-supercapacitor hybrid energy storage control scheme for mine electric locomotive

The starting and acceleration of the mine electric locomotive requires instantaneous high-power output of the power supply. The power density of lead-acid battery is low, which cannot meet the high-power demand of the mine electric locomotive. In order to make up for the shortage of the battery as a single power supply for the mine electric locomotive, A battery-supercapacitor hybrid storage system (HES) with lead-acid battery as main power supply and supercapacitor as auxiliary power supply is proposed. A multi-input DC/DC converter is adopted to control the output of the HES under different working conditions of the electric locomotive, and the bidirectional power control of the HES is realized. The simulation results show that the HES scheme plays a good role in driving and energy feedback of the mine electric locomotive.

Bidirectional synchronization control for an electrohydraulic servo loading system

Synchronism is one of the most important factors for electrohydraulic servo loading systems with multi-axis. As electrohydraulic servo loading systems have a large output force/torque, the coupling between each axis can cause great nonlinearities and uncertainties, which seriously deteriorates the performance of the systems. In this paper, an electrohydraulic servo loading system is used for studying its bidirectional synchronization control. The mechanism of the coupling between two cylinders from two directions is discussed and the experiment results of coupling are obtained. A bidirectional synchronization iterative learning control (BSILC) method is designed to improve the tracking performance, robustness and compensate the synchronization error. The simulation and the experiment have been conducted. The results indicate that the control strategy proposed in this paper is valid. The tracking performance, robustness and synchronism of the electrohydraulic servo loading system have been remarkably improved.

Wind Tunnel Study on Bidirectional Vibration Control of Lattice Towers with Omnidirectional Cantilever-Type Eddy Current TMD

An omnidirectional cantilever-type eddy current tuned mass damper (ECTMD) for lattice towers is introduced to suppress bidirectional vibration of lattice towers, in a form of a cantilever beam with a tip magnet mass. The damping of the ECTMD can be easily changed by tuning the amount of the current. A typhoon-fashion wind environment is simulated for the wind tunnel test. Test results show that there exists an optimal damping of the ECTMD along with an optimal frequency ratio. The scaled aeroelastic model is tested under various wind conditions, and a good effectiveness of ECTMD is observed. The wind directions, perpendicular and parallel to the cross-arm, are the most critical for the design of ECTMD, as the vibration mitigation in either of these two cases is relatively weaker. Finally, a simplified model is established for theoretical analysis in the frequency domain, whereby the variance responses of the tower with and without ECTMD are computed. The numerical results agree well with the experimental results, which corroborates the feasibility of using the proposed omnidirectional cantilever-type ECTMD in suppressing the vibrations of the tower in both along-wind and across-wind directions.