Bidirectional Control Research Articles

Robust Bidirectional Platoon Control for Mesh Stability of Vehicular Systems With Uncertain Kinematics and Dynamics

Robust Bidirectional Platoon Control for Mesh Stability of Vehicular Systems With Uncertain Kinematics and Dynamics

Bi-directional extensional control of the Berane Basin formation, northern Montenegro

The Berane Basin is a Miocene, northeast-southwest oriented intramountain basin of the Dinarides, overlying the pre-neotectonic basement of the Drina-Ivanjica unit, the East Bosnian-Durmitor unit and the Western Vardar Zone. The structural evolution and the tectonic regimes that controlled the formation of the Berane Basin are not fully understood. In this paper, we conducted field kinematic analysis by applying fault-slip inversion to derive paleostress regimes and study the deformation phases that led to the formation of the Berane Basin. Observed deformation is related to the latest Oligocene-Miocene extension in two directions, perpendicular and parallel to the Dinarides orogen. Such bi-directional extension resulted in a complex fault pattern where, among observed normal, oblique and strike-slip faults, those with oblique-normal slip dominate. The observed faults likely form a system of mutually overprinting half-grabens, mainly driven by orogen-parallel extension associated with the large-scale regional Skadar-Pec Fault, while orogen-perpendicular extension has subordinate effects on the Berane Basin formation.

A Novel Bi-directional Grid Inverter Control Based on Virtual Impedance Using Neural Network for Dynamics Improvement in Microgrids

A Novel Bi-directional Grid Inverter Control Based on Virtual Impedance Using Neural Network for Dynamics Improvement in Microgrids

Assessment of TENS-Evoked Tactile Sensations for Transradial Amputees via EEG Investigation.

Most of current prostheses can offer motor function restoration for limb amputees but usually lack natural and intuitive sensory feedback. Many studies have demonstrated that Transcutaneous Electrical Nerve Stimulation (TENS) is promising in non-invasive sensation evoking for amputees. However, the objective evaluation and mechanism analysis on sensation feedback are still limited. This work utilized multi-channel TENS with diverse stimulus patterns to evoke sensations on four non-disabled subjects and two transradial amputees. Meanwhile, electroencephalogram (EEG) was collected to objectively assess the evoked sensations, where event-related potentials (ERPs), brain electrical activity maps (BEAMs), and functional connectivity (FC) were computed. The results show that various sensations could be successfully evoked for both amputees and non-disabled subjects by customizing stimulus parameters. The ERP confirmed the sensation and revealed the sensory-processing-related components like N100 and P200; the BEAMs confirmed the corresponding regions of somatosensory cortex were activated by stimulation; the FC indicated an increase of interactions between the regions of sensorimotor cortex. This study may shed light on how the brain responds to external stimulation as sensory feedback and serve as a pilot for further bidirectional closed-loop prosthetic control.

Bidirectional Active Equalization Control of Lithium Battery Pack Based on Energy Transfer

Bidirectional Active Equalization Control of Lithium Battery Pack Based on Energy Transfer

A Bidirectional Three-Level Converter Control With Shared Control Circuit and Single-Point Sensing for Flying Capacitor Balance

A Bidirectional Three-Level Converter Control With Shared Control Circuit and Single-Point Sensing for Flying Capacitor Balance

A Bidirectional Human-Machine Control Interface Based on Virtual Fixtures for Safe Teleoperation of Hyper-Redundant Robots

A Bidirectional Human-Machine Control Interface Based on Virtual Fixtures for Safe Teleoperation of Hyper-Redundant Robots

Bidirectional vibration control for fully-coupled floating offshore wind turbines

The vast and stable wind resources present in deep waters have made deep-sea floating wind power the mainstream trend for future development. However, the operating environment of offshore floating wind turbines is complex and variable. The joint action of wind and waves causes significant platform motion and turbine vibration, reducing power generation efficiency, causing structural damage, and shortening the service life of turbines. Hence, this study focuses on the NREL 5 MW DeepCwind semi-submersible wind turbine and establishes a fully-coupled floating wind turbine model utilizing the SIMPACK multi-body dynamics software. The model includes aero-, hydro-, flexible body structure, mooring, control, and transmission chain components. 3D pendulum tuned mass dampers (3D-PTMD) and bilinear tuned mass dampers (2TMDs) are designed to control the bidirectional vibration causes due to wind-wave misalignment in the platform motion and nacelle displacement of the floating wind turbine. The research results show that: For the roll and pitch of the platform, there is only one platform roll or pitch main frequency, and the amplitude at the main frequency can be effectively reduced by setting the frequency of 2TMDs near the main frequency, thereby suppressing the vibration of the platform; For the displacement of the nacelle, in addition to the main frequency of platform roll or pitch, there is also a secondary frequency of first-order bending of the tower, 2TMDs corresponding to the main frequency can effectively reduce the amplitude at the main frequency, and 3D-PTMD corresponding to the secondary frequency can effectively reduce the amplitude at the secondary frequency, it is better to configure 2TMDs alone than 3D-PTMD alone, and it is best to configure both at the same time.

Item exposure and utilization control methods for optimal test assembly

Exposure control is an important component of computerized adaptive testing. Exposure control is often used to secure test content by preventing item overexposure, and also to balance item utilization by avoiding item underexposure. Content balancing is another important component of computerized adaptive testing. The shadow-test approach to content balancing has many practical merits, including that it ensures complete satisfaction of all content requirements in every assembled test. Several exposure control methods have been developed over the years. The current study describes modifications to existing exposure control methods for use with shadow-test-based adaptive testing, with the objective of achieving bidirectional exposure control. The performances of the modified methods were compared with respect to item exposure and utilization along with ability estimation accuracy. For the purpose of comparison, a Monte Carlo simulation was performed using realistic item pools and content constraints. Implications for real-world applications are discussed.

Adaptive power-sharing strategy in hybrid AC/DC microgrid for enhancing voltage and frequency regulation

This paper introduces a new adaptive control strategy for power-sharing in a hybrid AC/DC microgrid (HMG). The existing interlink converter (ILC) control methods exhibit limitations under heavy load and contingency conditions. To overcome this limitation, a bidirectional control strategy is proposed for the ILC, which effectively coordinates battery energy storage systems (BESSs) in both sub-grids while mitigating stress on the ILC and BESSs. The control strategy utilises the state of charge (SoC) and instantaneous power of the BESSs to stabilise frequency and DC voltage on the AC and DC sub-grids, respectively, enabling autonomous operation and plug-and-play capability. Stability analysis employing root locus and a stress level relaxation index for BESSs are presented. Performance evaluation based on the moving mean square error criterion validates the effectiveness of the control strategy. Simulation results using MATLAB/SIMULINK demonstrate the superior performance of the proposed strategy in regulating both voltage and frequency within the system over the existing control approaches. Furthermore, the proposed approach significantly reduces stress levels on the BESSs in different operation conditions.

Model-Free Bidirectional Synchronous Rectification Control Scheme for LLC-Based Energy Storage System in Electric-Vehicle Energy Router

LLC resonant converters have been widely used in electric-vehicle energy router (EVER) as part of energy storage (ES) system, resulting in the increased demand for bidirectional synchronous rectification (SR) control. However, conventional bidirectional SR schemes are respectively limited by high cost of current sensing, difficulty of high voltage sensing, narrow operating range or high computational burden, especially for EVER. To deal with this problem, this paper proposes a model-free bidirectional SR control scheme for LLC-based ES system in EVER. Firstly, a novel SR tuning principle based on Kirchhoff’s law and phase relationship between inverter control signal and rectifier-side current is proposed. It no longer needs to calculate complicated models. Based on this principle, SR control signals in both forward and reverse modes are tuned by known signals available from main controller in ES system. To this end, no additional sensing component is required and the cost of SR is reduced. Meanwhile, an adaptive DC bus current compensation strategy is designed. It can guarantee high SR accuracy in reverse mode without sensing DC bus current. Moreover, an analog-digital mixed implementation is provided in which signal computation is performed by analog circuit. With these effects, the proposed scheme can achieve bidirectional SR control effectively over a wide operating range with low computational burden on controller. A 400-V/36-V 1-kW bidirectional LLC prototype is built to verify the proposed scheme.

Bidirectional controller supported inductively coupled dual buck converter based DSTATCOM with passive filterfor PQ improvement

This research paper explains about the bidirectional controller (BC) supported inductively coupled dual buck converter (IC-DBC) based distributed static compensator (DSTATCOM) with passive filter (PF) for 3-ф 3-wire (3P3W) power distribution system (PDS). The most significant concern in the PDS is power quality (PQ) control. Hence, innovative approach is proposed by considering concept and benefits of BC, inductive coupled filtering transformer (IFCT), passive filter and dual buck converter. Equivalent circuit for IC-DBC based DSTATCOM is realized in view of impedance of transformer and direct coupled dual buck converter (DC-DBC) based DSTATCOM to disclose the filtering mechanism. The supremacy of the proposed DSTATCOM is introduced by comparing its simulation outcomes with DC-DBC based DSTATCOM and IC-DBC based DSTATCOM in terms of better harmonics curtailment, power factor advancement, load balancing & reduced DC link voltage compared to other approaches as per IEEE standard.

Externally Heated Diamond ANvil Cell Experimentation (EH-DANCE) for studying materials and processes under extreme conditions.

Externally heated diamond anvil cells provide a stable and uniform thermal environment, making them a versatile device to simultaneously generatehigh-pressure and high-temperature conditions in various fields of research, such as condensed matter physics, materials science, chemistry, and geosciences. The present study features the Externally Heated Diamond ANvil Cell Experimentation (EH-DANCE) system, a versatile configuration consisting of a diamond anvil cell with a customized microheater for stable resistive heating, bidirectional pressure control facilitated by compression and decompression membranes, and a water-cooled enclosure suitable for vacuum and controlled atmospheres. This integrated system excels with its precise control of both pressure and temperature for mineral and materials science research under extreme conditions. We showcase the capabilities of the system through its successful application in the investigation of the melting temperature and thermal equation of state of high-pressure ice-VII at temperatures up to 1400K. The system was also used to measure the elastic properties of solid ice-VII and liquid H2O using Brillouin scattering and Raman spectra of carbonates using Raman spectroscopy, highlighting the potential of the EH-DANCE system in high-pressure research.

A critical review on contemporary power electronics interface topologies to vehicle‐to‐grid technology: Prospects, challenges, and directions

AbstractWith the evolution of the smart grid concept, the production of electric vehicles (EVs) is predicted to rise because of environmental concerns, technological advancements, and improvements in EV management. Vehicle‐to‐grid (V2G) is an enabling, realistic, and affordable technology to cope with a large number of EVs, increase energy sustainability, provide economical solutions, satisfy user‐side consumers, and facilitate power flow to the grid. Power electronics (PE) converters, particularly bidirectional power converters, are promising interfaces for V2G infrastructure because they determine the characteristics and functionalities of V2G. Therefore, this study provides an extensive review of the characteristics, technological aspects, and visions of V2G infrastructure. This review helps to identify the current state, most recent developments, and problems related to bidirectional interface topologies and control strategies in V2G infrastructure. It further examines the classification of chargers or dischargers based on numerous factors, including limitations and impacts. Furthermore, the benefits, challenges with possible mitigation solutions, and future outlooks in the implementation of V2G technology are discussed. This review is planned to serve as a reference for existing work in V2G frameworks, PE interfacing topologies, and control strategies, and to also facilitate a guideline for future work that can be implemented to flourish V2G technology.

Bidirectional Neuronal Control of Epileptiform Activity by Repetitive Transcranial Focused Ultrasound Stimulations.

Repetitive stimulation procedures are used in neuromodulation techniques to induce persistent excitatory or inhibitory brain activity. The directivity of modulation is empirically regulated by modifying the stimulation length, interval, and strength. However, bidirectional neuronal modulations using ultrasound stimulations are rarely reported. This study presents bidirectional control of epileptiform activities with repetitive transcranial-focused ultrasound stimulations in a rat model of drug-induced acute epilepsy. It is found that repeated transmission of elongated (40s), ultra-low pressure (0.25MPa) ultrasound can fully suppress epileptic activities in electro-encephalography and cerebral blood volume measurements, while the change in bursting intervals from 40 to 20s worsens epileptic activities even with the same burst length. Furthermore, the suppression induced by 40s long bursts is transformed to excitatory states by a subsequent transmission. Bidirectional modulation of epileptic seizures with repeated ultrasound stimulation is achieved by regulating the changes in glutamate and γ-Aminobutyric acid levels, as confirmed by measurements of expressed c-Fos and GAD65 and multitemporal analysis of neurotransmitters in the interstitial fluid obtained via microdialysis.

Elevated Serotonin in Mouse Spinal Dorsal Horn Is Pronociceptive.

Serotonergic neurons in the rostral ventral medulla (RVM) contribute to bidirectional control of pain through modulation of spinal and trigeminal nociceptive networks. Deficits in this pathway are believed to contribute to pathologic pain states, but whether changes in serotonergic mechanisms are pro- or antinociceptive is debated. We used a combination of optogenetics and fiber photometry to examine these mechanisms more closely. We find that optogenetic activation of RVM serotonergic afferents in the spinal cord of naive mice produces mechanical hypersensitivity and conditioned place aversion (CPA). Neuropathic pain, produced by chronic constriction injury of the infraorbital nerve (CCI-ION), evoked a tonic increase in serotonin (5HT) concentrations within the spinal trigeminal nucleus caudalis (SpVc), measured with liquid chromatography-tandem mass spectroscopy (LC-MS/MS). By contract, CCI-ION had no effect on the phasic serotonin transients in SpVc, evoked by noxious pinch, and measured with fiber photometry of a serotonin sensor. These findings suggest that serotonin release in the spinal cord is pronociceptive and that an increase in sustained serotonin signaling, rather than phasic or event driven increases, potentiate nociception in models of chronic pain.

Adaptive signal light timing for regional traffic optimization based on graph convolutional network empowered traffic forecasting

With the acceleration of urbanization, urban traffic congestion is becoming more and more serious, in which the timing of signal lights for regional traffic optimization is particularly important. Since existing signal lights-based traffic optimization technologies, especially green wave, do not take the regional traffic follow into consideration, therefore not being efficient. Therefore, we propose Adaptive Signal Light Timing for Regional Traffic Optimization based on Graph Convolutional Network Empowered Traffic Forecasting. First, we propose a multi-intersection traffic flow prediction model, namely, A-GCN+ with an improved prediction accuracy of 6.3%, which utilizes the attention-aggregated graph convolutional neural networks (A-GCN) and temporal convolutional networks (TCN) to extract spatial and temporal features of the traffic flow. Second, we propose a dynamic regional traffic signal coordination optimization control method, which utilizes the predicted intersection approach traffic flow from A-GCN+ and combines it with the improved whale optimization algorithm (IWOA) to obtain the optimal solution for the regional average vehicle delay model. Finally, we propose a bidirectional green wave automatic control method for the main line, which utilizes the optimized results of dynamic regional traffic signal timing and employs a multi-strategy fusion graphical method to obtain the dynamic main line bidirectional green wave. Experimental results show that compared to the traditional graphical method, the multi-strategy fusion graphical method increases the green wave bandwidth by 20%. The mainline bidirectional green wave adaptive coordinated control method improves main line traffic efficiency by 32.3% and regional network traffic efficiency by 8.7%.

National-scale bi-directional EV fleet control for ancillary service provision

Deploying real-time control on large-scale fleets of electric vehicles (EVs) is becoming pivotal as the share of EVs over internal combustion engine vehicles increases. In this paper, we present a Vehicle-to-Grid (V2G) algorithm to simultaneously schedule thousands of EVs charging and discharging operations, that can be used to provide ancillary services. To achieve scalability, the monolithic problem is decomposed using the alternating direction method of multipliers (ADMM). Furthermore, we propose a method to handle bilinear constraints of the original problem inside the ADMM iterations, which changes the problem class from Mixed-Integer Quadratic Program (MIQP) to Quadratic Program (QP), allowing for a substantial computational speed up. We test the algorithm using real data from the largest carsharing company in Switzerland and show how our formulation can be used to retrieve flexibility boundaries for the EV fleet. Our work thus enables fleet operators to make informed bids on ancillary services provision, thereby facilitating the integration of electric vehicles.

Key-aggregate based access control encryption for flexible cloud data sharing

Cloud computing has become the priority for users to store and share data due to its numerous tempting advantages. The “encryption-before-outsourcing” mechanism is necessary to protect data privacy against the semi-trusted cloud server. Key-Aggregate Cryptosystem (KAC) is a novel encryption paradigm for cloud data sharing. It enables users to decrypt multiple data encrypted with different keys using a constant size aggregate key. When selectively sharing data, the KAC effectively addresses the challenges of expensive key management in symmetric encryption (SE) and eliminates the need for multiple copies of ciphertexts in public key encryption (PKE). However, previous KAC schemes can only control what data users are allowed to receive by distributing aggregate keys, but not what data users can send. This limitation could potentially allow a malicious data owner to leak sensitive information by distributing aggregate keys to unauthorized users. Therefore, this paper aims to design the key-aggregate cryptosystem with bidirectional access control, which can control both what the user can receive and what the data owner can send. Inspired by access control encryption (ACE), we first propose a key-aggregate based access control encryption with user level (KA-ACE-UL) system that can control whether a sender can share his data with a receiver. Then, we investigate a finer-grained access control policy and propose a key-aggregate based access control encryption with user-data level (KA-ACE-UDL) system that can control the data classes a sender can share with a receiver. We instantiate the KA-ACE-UL and KA-ACE-UDL schemes based on Chu et al.’s KAC scheme. We prove our proposed schemes can achieve both secure data storage and controlled data sharing, ensuring security against unauthorized receivers and malicious senders. Finally, theoretical performance analysis and practical experiments show the efficiency of our proposed schemes.

Integral Sliding Mode Control-Based Robust Bidirectional Platoon Control of Vehicles With the Unknown Acceleration and Mismatched Disturbance

This paper proposes integral sliding mode control (ISMC)-based robust bidirectional platoon control methods in the longitudinal platoon for vehicles with unknown acceleration and mismatched disturbance. A finite time robust estimator (FTRE) is presented to estimate the practically unknown acceleration and mismatched disturbance of adjacent vehicles. In addition, the matched disturbance in the vehicle is also compensated for to further ensure the robustness of the platoon control. A modified constant time headway (MCTH) policy that removes the influence of the initial spacing and velocity error is defined to improve the transient response of the platoon control. Two robust platoon control methods, a nonlinear disturbance observer (DOB)-based ISMC and an adaptive dual-layer super-twisting ISMC (STISMC), are proposed. The proposed methods based on the nonlinear DOB and ISMC are more effective against highly nonlinear disturbances than the existing linear DOB-based methods and the disturbances can be compensated at all times by eliminating the reaching mode, unlike the exiting SMC-based methods. Furthermore, the proposed adaptive dual-layer STISMC provides a continuous control input that guarantees the finite time convergence of the sliding mode variables to zero without requiring an upper bound on disturbance. Both simulation and experimental results are provided to demonstrate the superior platoon control performance of the adaptive dual-layer STISMC method compared to both the existing linear DOB-based robust platoon control method using ISMC and the nonlinear DOB-based ISMC method.