Additional Control Signals Research Articles

Adaptive frequency driving scan driver based on a‐InGaZnO TFTs for extremely low‐power displays

AbstractIn this paper, we propose a novel scan driver combined with a logic circuit using amorphous indium‐gallium‐zinc‐oxide (a‐InGaZnO) thin‐film transistors (TFTs) in order to enhance the electrical stability and reduce power consumption in display panels. The latest mobile displays with high resolution and refresh rates consume more battery power, which inevitably limits portability and usability. The proposed scan driver can mask the signal by combining the output stage with a logic circuit, thereby blocking the output pulse for static images. This allows the display panel to operate in a partial driving mode depending on the display content. Due to the masking of the scan driver's output pulses, the connected pixel circuits are consistently maintained in the same state as the previous frame, leading to a lower refresh rate and reduced power consumption. Furthermore, by constructing additional control signals, the proposed scan driver can operate stably in depletion mode under a ∆VTH = −3 V.

Percolation-induced explosive synchronization in pinning control

Percolation and synchronization are two paradigmatic examples of phase transitions that can take place in network dynamical systems. In this paper, we show how percolation can induce an explosive, first-order transition to synchronization in pinning control, a classical feedback strategy that exploits the network topology to drive the network dynamics to a desired synchronous solution. When the number of control signals is limited by physical or economical constraints, only a fraction of the network nodes can be effectively synchronized onto the desired trajectory. Determining the sensitivity of this fraction to the number of pinning control signals is then key to decide if it is worth adding additional control signals. We find that when the network graph percolates, that is, it becomes endowed with a giant strongly connected component (GSCC), an explosive transition to synchronization occurs as we increase the fraction of nodes where we can inject the pinning signals. Motivated by this numerical observation, we exploit the probabilistic conditions that ensure the presence of a GSCC to predict the number of pinning signals such that all of its nodes will converge to the desired synchronous trajectory. We test the validity and robustness of our analytical derivations through numerical simulations on both synthetic and real networks, proving the benefit of such analysis in supporting decision-making for control design.

Reliable cooperative communication in cognitive vehicular networks for intelligent transportation systems

SummaryRapid intelligent transportation systems (ITS) innovations need a reliable MAC protocol to enable massive nonsafety message delivery and high‐priority safety broadcasts. The significant rise in spectrum need is regulated by collaboration in cognitive vehicular networks (CVNs). For QoS improvement, a reliable cooperative MAC for CVNs (CCVN‐MAC) is presented in this study. CCVN allows vehicles to collaborate and share channel status information, allowing for proactive channel switching in case of a legacy user (LU) appearance. To enable transmission mode selection, additional control signals are included. Using the suggested cooperative makeup technique, the helper nodes resend failed transmission. A Markov chain represents the protocol, and NS‐2 is used to evaluate it for several performance characteristics. Compared with conventional MAC techniques, the proposed protocol depicts improved performance, including depreciation of 70% in average latency and an increment of 42.4% in throughput.

Historical Background of the Origin of the Speeddroop, Additional Control Signals and Analogic Retrofit of a Governor of a Francis Turbine, Using Operational Amplifier IC741

It is well known that governors of turbines, moving synchronous machines are responsible to maintain the rotation of the rotor of the generator constant and then the electric frequency constant, independently of the changes of electric loads connected to the power electric net. This paper treats about the origin and necessity of the permanent and transitory speedoops in the control mash of a governor. First, we develop the historical background origin of a governor. The basic controls actions are studied, and the analogic circuits related, using operational amplifiers. Then, as an easier way, the author uses an analogic generic PID governor to explain how the permanent speedroop is needed to set the power delivered by a hydraulic turbine (Francis) and then the transitory speedroop. Additional control signal as Power Joint Control and Automatic Generation Control-AGC are introduced. As a suggestion, a simple analogic Power Joint Control circuit example, using operational amplifier 741 is given, but not tested in a workbench. The using of the Automatic Control Generation-AGC, a supplementary control, is introduced because of the necessity to correct the frequency deviations. It is also given a simple circuit example of AGC, not tested in a workbench. This paper ends with an analogic retrofit of a governor of Francis turbine of decade of 1960 of 180 MW using analogic electronic. The author employs IC 741 operational amplifier. Prior simulations of the Laplace’s model of the governor were made using Matlab-Simulink. Because of the little acquisition time of the available oscilloscope, the author made a transformation in the original Laplace model that reduced the step response time by a factor of 20 but the methodology and know-how to make an analogic retrofit was conquered. The governor was built and tested in a workbench. The hydraulic circuit was simulated with 741 amp ops. The electronic simulation corresponded to the mathematics simulations showing the success of the analogic retrofit. The physical space needed by the equipment was reduced from the size of a refrigerator to a size of a shoe box. Although an analogic retrofit is considered obsolete today, the analogic retrofit has robustness, and it is cheaper.

An H8 Current-Source Inverter Using Single-Gate WBG Bidirectional Switches

Due to the high forward voltage drop of reverse-blocking (RB) switches, conventional current-source inverters (CSIs) typically suffer efficiency penalties. Bidirectional (BD) switches, on the other hand, can also block reverse voltages but with less conduction loss than RB switches, making them more attractive candidates for CSI switches. This article discusses the difficulties inherent in implementing BD switches in CSIs, such as dc-link overvoltage, interphase short circuit, more complicated commutation schemes, high body diode conduction loss, and additional gate control signals. To address these issues, a new CSI topology (H8-CSI-BD) is proposed, which is optimized for the use of single-gate wide bandgap (WBG) BD switches. The proposed topology and its modulation scheme guarantee safe operation of CSI, eliminate BD switch’s body diode conduction loss, and achieve significant efficiency improvement. In addition, its requirement for single-gate control signals for its BD switches simplifies control and gate drive circuits noticeably. The advantages of the H8-CSI-BD topology over the other CSIs using either RB or BD switches are confirmed by analysis, simulation, and experimental results.

A neural flexible PID controller for task-space control of robotic manipulators.

This paper proposes an adaptive robust Jacobian-based controller for task-space position-tracking control of robotic manipulators. Structure of the controller is built up on a traditional Proportional-Integral-Derivative (PID) framework. An additional neural control signal is next synthesized under a non-linear learning law to compensate for internal and external disturbances in the robot dynamics. To provide the strong robustness of such the controller, a new gain learning feature is then integrated to automatically adjust the PID gains for various working conditions. Stability of the closed-loop system is guaranteed by Lyapunov constraints. Effectiveness of the proposed controller is carefully verified by intensive simulation results.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ЭФФЕКТИВНОСТИ РАЗЛИЧНЫХ МОДЕЛЕЙ ЭЛЕКТРИЧЕСКОГО КОНТУРА ЭЛЕКТРОДУГОВОЙ ПЕЧИ ДЛЯ ИСПОЛЬЗОВАНИЯ В ЦИФРОВОМ ДВОЙНИКЕ

usRelevance Nowadays the metallurgical industry is rapidly developing, which requires a continuous search for innovative solutions aimed at providing consumers with high-quality metal products in the required volumes. To achieve this goal, modern enterprises are faced with a number of scientific and technical tasks, which include increasing the energy efficiency of production. An innovative tool in this case is the development of methods for the digitalization of production, including implementation of digital twins for the control of complicated technological systems. The most energy-intensive equipment at metallurgical enterprises is electric arc furnace (EAF). As operating experience shows, control systems for electrical modes of such units do not always allow EAFs to operate with optimal time, energy and technological parameters, which in turn leads to increased operating costs, such as increased specific energy consumption, consumption of electrodes, etc. As a solution to this problem, a number of scientific studies propose the use of a digital twin for dynamic adaptation of the parameters of the EAF electrical mode control system, capable of calculating the settings of control algorithms during the melting process in such a way as to obtain optimal electrical and technological modes at different stages, as well as optimal dynamic performance quality of impedance regulation on the secondary side of the furnace transformer. One of the important stages in this case is the form of representation of the electrical circuit inside of the digital twin, since the adequacy of the output parameters and the accuracy of the operation of the entire control system will depend on this. Based on the above, an urgent task is to develop an effective method for modeling the electrical circuit of the electric arc furnace for application in a digital twin. Aim of research The paper is devoted to the results of research aimed at the use of various mathematical models of the electrical circuit for application in electric arc furnace’s digital twin. Research methods To process the experimental data, mathematical modeling methods were used in the Matlab environment with the Simulink application. All studies were carried out on the basis of experimental data obtained at operating equipment at domestic and foreign metallurgical plants. Results The significance of the research results lies in increasing the energy efficiency of arc steel-smelting furnaces through the use of a digital twin. This solution will allow to provide the optimal selection of transformer tap reactor tap and operating curve number for each stage of melting, as well as analyze the position of operating points on the electrical characteristics and generate additional control signals for dynamic correction of the lengths of electric arcs. The methods of electric circuit modeling in digital twins presented in the work allow to configure the melting program and optimize the parameters of nonlinear impedance or conductivity controllers of the secondary side of the EAF’s transformer. In addition, it makes possible the analyze and adaptation of the auxiliary blocks in control system — arc ignition, current control and correction of regulator setting signals as a function of the voltage deviation on the primary side of the furnace transformer (relatively to the rated value). Problems associated with calculating matrices of settings for impedances and conductances of the secondary circuit of an EAF for all combinations of transformer taps, reactor taps and all values of operating curves can also be solved. Mathematical models are implemented in the Matlab software environment with the Simulink application.

Control of spoke movement in DCMS plasmas

Spokes appear as zones of increased ionisation in magnetron sputtering discharges. They rotate in front of a 2″ target at a natural frequency between a few 10 kHz and several 100 kHz and move in or anti direction depending on plasma power. Spokes are known to cause strong gradients in plasma density and potential and can, thus, increase the ion transport from target to substrate. Here, we explore the possibility to control spokes by applying a given frequency f to a set of control probes around the plasma to lock the spoke movement. The efficiency of this locking is analyzed by diagnostic probes and energy resolved mass spectrometry, which measure the integrated ion fluxes leaving the magnetic trap region. It was found that the spoke movement could be locked to the external control signal at frequency f around the natural spoke frequencies f 0. The additional control signal affects the ion flux twofold: (i) a 15% increase in ion flux towards the substrate and a 15% reduction in radial direction irrespective of control frequency is observed, which is explained by a change in plasma confinement since electric fluctuations at the separatrix are induced; (ii) the locking at f causes an increase in ion current in normal as well as in radial direction for f < f 0 and a reduction for f > f 0. This is explained by either longer or shorter residence times of ions in the electric fields caused by the spoke, or by an enhancement of these fields caused by the control. Using this spoke controlling technique an overall increase of ion flux towards the substrate of up to 30% was realized.

A Fair and Cooperative MAC Protocol for Heterogeneous Cognitive Radio Enabled Vehicular Ad-Hoc Networks

Advancements in intelligent transportation necessitate a dependable medium access control (MAC) protocol to enable high-priority safety broadcasts. Implementing cognitive radio-based vehicular ad-hoc networks (CR-VANETs) alleviates the significant growth in spectrum demand. The architecture must deploy multiple networks to make CR-VANET viable; however, the MAC design is a substantial challenge. The hardware-limited vehicles have varied characteristics and do not attain the same performance when provided with equal resources, posing a fairness concern. The resource allocation should balance two conflicting objectives: performance should be increased, prioritizing a few users under better conditions, and fairness among users should be emphasized, which reduces the overall performance. This paper presents a Fair and Cooperative MAC protocol for heterogeneous CR-VANETs (FCCR-MAC) to find this balance. In the event of a primary user appearance, cooperation allows pro-active channel switching. In FCCR-MAC, mode selection and retransmission of unsuccessful broadcasts are enabled by including additional control signals. By assisting users in determining the identities of others, cooperation also improves the system’s fairness. Markov Chain and the Karush–Kuhn–Tucker (KKT) conditions are utilized to offer a unified mathematical explanation of the throughput versus fairness trade-off optimization problem. According to the findings, the FCCR-MAC protocol outperforms other protocols with better fairness.

Adaptive bus‐voltage control of ship power system with online fluctuation prediction

To ensure the power quality of a ship power system under disturbances due to changing sea states, an adaptive bus-voltage controller with online load power fluctuation prediction is proposed to stabilize the ship bus voltage. The controller uses an online sequence extreme learning machine to update the output weight matrix and achieve an accurate online prediction of the ship load power fluctuations under the disturbance of random uncertainties. A stable additional control signal is provided to the bus-voltage controller for adaptive operation. The prediction results are used to optimize the coordinated control of multiple generation systems and improve the bus-voltage control performance by updating the droop control coefficients online. The adaptability provided by the online prediction algorithm and the performance of the bus-voltage control are verified using recorded voyage data of an offshore marine engineering transport vessel.

Ultra-Efficient and Robust Auto-Nonvolatile Schmitt Trigger-Based Latch Design Using Ferroelectric CNTFET Technology.

In designing ultra-efficient noise immune nanoscale circuits and systems, Schmitt triggers (STs) are vital components influencing total functionality. This article proposes an ultracompact ST using ferroelectric carbon nanotube field-effect transistors (Fe-CNTFETs) and a robust ST latch. By using the unique electrical futures of the Fe-CNTFETs, the proposed ST has been designed in a particular way to only employ two transistors similar to a conventional binary inverter. Moreover, by utilizing the negative capacitance feature of the Fe-CNTFETs, the proposed ST can perform the backup and restore operation during a scheduled power gating or a sudden power outage without imposing any additional transistors, interconnects, and control signals. The proposed ST latch is hardened to soft errors occurring due to unwanted single-event upsets (SEUs). Our extensive simulations demonstrate that our proposed ST latch offers lower transistors counts (on average 34%) and more energy savings (on average 79%). On the other hand, our design has shown 5.6 times on average higher critical charge tolerance than the previous counterparts due to its soft error hardening circuity and the superior hysteresis behavior of the proposed Fe-CNTFET-based ST. Moreover, the auto-nonvolatility of the proposed ST makes the proposed latches immune to the sudden power outage, which was not devised in the previous ST latches. Our results show new pathways in designing ultracompact and efficient nonvolatile ST latches using the Fe-CNTFET technology.

Hybrid soft switching DC–DC boost converter

AbstractIn this study, hybrid soft switching (HSS) DC–DC boost converter is proposed. The proposed converter operates as the conventional discontinuous conduction mode (DCM) pulse‐width modulated (PWM) DC–DC boost converter at light loads. When the output power increases, the snubber cell is activated, and the converter operates as frequency controlled soft switching resonant converter. Thus, higher efficiency is obtained at high power levels. In the proposed converter, the snubber cell works with a simple on–off logic instead of PWM control. Thus, it has a quite simple structure consisting of only a switch and a snubber capacitor, and does not need an additional PWM control signal. Hence, the proposed converter has the advantages of conventional DCM PWM converters while operating with higher efficiency at higher power levels. There is no additional voltage stress on any semiconductor power devices. Theoretical analysis is verified with a laboratory application of a DC‐DC boost converter having input voltage of 90 V, output voltage of 400 V and output power of 1 kW.

Analog and Digital Phase Modulation and Signal Transmission with Spin-Torque Nano-Oscillators

Researchers present a method of phase modulation and phase-shift keying for spin-torque nano-oscillators (STNOs), and demonstrate transmission of a voice signal (telephony) with their STNO-based gear. The key elements of the proposed method are the ability of an STNO to be synchronized by an external signal, and to shift its phase relative to the source's phase according to an additional control signal. These properties allow not only control of the phase, but also reduction of phase noise, which is a main issue for all oscillators with nanoscale dimensions. The results comprise a significant advance for wireless data and signal communication with nano-oscillators.

Designing optimal power system stabilizer for synchronous generator with and without damper windings

This paper aims at effective damping of low-frequency oscillations (LFO) associated with synchronous generators (SG). LFO are excited by system disturbances as sudden change on the load, switching events, and malfunction of the turbine controller. Poor damping of LFO affects the stability of the generation system, in severe cases may result in instability and damage to prime-movers. The negative effect of the automatic voltage regulator (AVR) is studied for SG without and with damper windings on the damping of oscillations. Minimizing the LFO is achieved by incorporating the power system stabilizer (PSS), which adds an additional control signal to AVR. Effective design of PSS to maximize the damping torque while maintaining the stability of SG variables. The problem is modelled as an optimization problem, the damping ratio of the mechanical modes is the objective function. The single-pole placement technique and the recently developed political optimizer are picked to determine the perfect PI parameters for PSS. The satisfactory performance of the proposed PSS is appraised by testing it against mechanical power disturbances. The obtained mathematical analytical expression makes it possible to determine easily the eigenvalues and step response for the speed and electromagnetic torque for SG in MATLAB environment.

Learning a deep motion interpolation network for human skeleton animations

AbstractMotion interpolation technology produces transition motion frames between two discrete movements. It is wildly used in video games, virtual reality and augmented reality. In the fields of computer graphics and animations, our data‐driven method generates transition motions of two arbitrary animations without additional control signals. In this work, we propose a novel carefully designed deep learning framework, named deep motion interpolation network (DMIN), to learn human movement habits from a real dataset and then to perform the interpolation function specific for human motions. It is a data‐driven approach to capture overall rhythm of two given discrete movements and generate natural in‐between motion frames. The sequence‐by‐sequence architecture allows completing all missing frames within single forward inference, which reduces computation time for interpolation. Experiments on human motion datasets show that our network achieves promising interpolation performance. The ablation study demonstrates the effectiveness of the carefully designed DMIN.1

Development of Accommodation System for Faults in Thrusters of Underwater Robots

The article discusses a solution to the problem of increasing the reliability of operation of underwater robots through the use of accommodation systems that compensate for the consequences of faults that appear in the thrusters. The following types of faults were considered: 1) a fault in the rotation speed sensor of thruster, causing error in its readings; 2) overheating of the motor or short-circuiting of several turns of the winding of its armature circuit, causing a change in the value of electrical resistance; 3) the appearance of an unknown external torque effect on the engine shaft, including when winding plants on the propeller. A new method for constructing accommodation systems is proposed, which contains three stages. At the first, the detection of emerging faults is carried out using the bank of diagnostic observers. Each observer is synthesized according to a special procedure in such a way that the residual formed by it is sensitive to the appearance of various combinations of possible faults. This allows to detect each specific fault. At the second stage, the values of sensor errors and deviations of the parameters of the thruster from their nominal values are estimated by additional variable structure observers. At the third stage, additional control signals for robot’s thrusters are formed. They ensure the stabilization of dynamic properties and quality indicators of thrusters in the event of faults. The results of mathematical modeling are presented, which have confirmed the operability and high efficiency of the synthesized accommodation system.

Teaching recurrent neural networks to infer global temporal structure from local examples

The ability to store and manipulate information is a hallmark of computational systems. Whereas computers are carefully engineered to represent and perform mathematical operations on structured data, neurobiological systems adapt to perform analogous functions without needing to be explicitly engineered. Recent efforts have made progress in modelling the representation and recall of information in neural systems. However, precisely how neural systems learn to modify these representations remains far from understood. Here, we demonstrate that a recurrent neural network (RNN) can learn to modify its representation of complex information using only examples, and we explain the associated learning mechanism with new theory. Specifically, we drive an RNN with examples of translated, linearly transformed or pre-bifurcated time series from a chaotic Lorenz system, alongside an additional control signal that changes value for each example. By training the network to replicate the Lorenz inputs, it learns to autonomously evolve about a Lorenz-shaped manifold. Additionally, it learns to continuously interpolate and extrapolate the translation, transformation and bifurcation of this representation far beyond the training data by changing the control signal. Furthermore, we demonstrate that RNNs can infer the bifurcation structure of normal forms and period doubling routes to chaos, and extrapolate non-dynamical, kinematic trajectories. Finally, we provide a mechanism for how these computations are learned, and replicate our main results using a Wilson–Cowan reservoir. Together, our results provide a simple but powerful mechanism by which an RNN can learn to manipulate internal representations of complex information, enabling the principled study and precise design of RNNs. Recurrent neural networks (RNNs) can learn to process temporal information, such as speech or movement. New work makes such approaches more powerful and flexible by describing theory and experiments demonstrating that RNNs can learn from a few examples to generalize and predict complex dynamics including chaotic behaviour.

A Wideband dB-Linear Variable-Gain Amplifier With a Compensated Negative Pseudo-Exponential Generation Technique

This article presents a wideband dB-linear variable-gain amplifier (VGA) with a compensated negative pseudo-exponential generation (C-NPEG) technique for high-speed applications. By shifting the concave and the convex function of an original negative pseudo-exponential generator (NPEG), two additional control signals are produced to manipulate two variable-gain Gilbert-cell-based amplifiers, respectively. Cascading these two stages with another variable gain stage controlled by the original NPEG, the multiplication of three different but mutually compensated control signals is realized. As a result, the dB-linear gain range of the overall VGA is extended, and the gain error is suppressed with the proposed C-NPEG technique. To further improve the VGA's gain while maintaining a wide bandwidth, a fixed-gain stage utilizing five common-source amplifiers with RC-degeneration and active feedback is implemented. Fabricated in 40-nm CMOS technology, the core circuit consumes 24.6-mA current (excluding the output buffer) under a power supply of 1.1 V and occupies an active die area of 0.038 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The measured gain of the overall VGA varies from -34 to 17 dB, while the dB-linear gain error over the 51-dB gain range is within ±1 dB. Meanwhile, the -3-dB bandwidth is relatively constant from 7 to 8 GHz under different gain settings.

No-instruction-set-computer design experience of flexible and efficient architectures for digital communication applications: two case studies on MIMO turbo detection and universal turbo demapping

The emerging flexibility need in designing application-specific processors dedicated for modules of digital receiver imposes a new design metric, which is added to the requirements of efficiency and productivity. In order to cope with the emerging flexibility requirement combined with the best performance efficiency, many application-specific processor design approaches have been proposed and investigated. In general, available design approaches that adopt dynamic scheduling of instructions add an overhead due to the instruction decoding. To minimize this overhead, several approaches have been introduced, which opt static scheduling. In this context, No-Instruction-Set-Computer (NISC) concept has been introduced to design application-specific processors without an instruction set. NISC concept proposes that there is no need to first design and then use an instruction set when the hardware is programmed by its designers rather than its users. NISC designing approach offers a good compromise between flexibility, productivity, and quality for the design of a digital system. In our work, NISC approach is explored through the design of flexible and efficient architectures dedicated for digital communication applications which fulfill the requirements imposed by multiple emergent communication standards. This paper introduces briefly the NISC concept and the corresponding design methodology. Also, it provides an overview of the related design approach. In addition, the relevance of NISC in realizing flexible and efficient implementation in the domain of digital communication is demonstrated through two case studies on MIMO turbo detection and universal turbo demapping. Both designed NISC-based architectures have been compared to state-of-the-art ASIP-based architectures using similar computational resources and supporting same flexibility parameters. The obtained results show that the proposed NISC-based architectures provide a significant improvement in execution performance while having reduced implementation costs. The results also illustrates how the control memory requirements depend on the application and the devised architecture choices. In the detector module, the adopted re-usability of allocated resources imposes separate controlling of each component; hence, additional control signals are implied. Whereas for the demapper module, implemented hardware components are considered to perform specific operations and to deal with the same type of data; hence, the number of control signals can be reduced significantly.

A novel cooperative MAC protocol for safety applications in cognitive radio enabled vehicular ad-hoc networks

Recent developments in intelligent transportation system (ITS) require a reliable medium access control (MAC) protocol to support the high-priority safety message broadcast. The rapid increase in spectrum demand is addressed by implementing cooperation in cognitive radio-based vehicular ad-hoc networks (CR-VANETs). In this paper, a novel cooperative MAC for CR-VANET (CCRV-MAC) is proposed for safety applications. CCRV facilitates collaboration among vehicles to exchange channel status reports for pro-active channel switching in the case of primary user (PU) appearance. Additional control signals are introduced to enable transmission mode selection. The helper nodes rebroadcast failed transmission by employing the proposed cooperative makeup strategy. The protocol is modelled using a Markov chain and is analyzed for various performance parameters using NS-2. It is also compared with two existing MAC protocols. In the results, CCRV shows enhanced throughput and packet delivery ratio. The average delay in CCRV MAC is reduced by approximately 37% compared to existing cognitive radio network (CRN) and vehicular ad-hoc network (VANET) based MAC approaches. Analysis of overhead and delay illustrates the reliability of CCRV as it suffers a maximum average delay of 69 ms under adverse conditions which is well below the permissible limit of 100 ms.