Unique Control Scheme Research Articles

A model-free method to learn multiple skills in parallel on modular robots

Legged robots are well-suited for deployment in unstructured environments but require a unique control scheme specific for their design. As controllers optimised in simulation do not transfer well to the real world (the infamous sim-to-real gap), methods enabling quick learning in the real world, without any assumptions on the specific robot model and its dynamics, are necessary. In this paper, we present a generic method based on Central Pattern Generators, that enables the acquisition of basic locomotion skills in parallel, through very few trials. The novelty of our approach, underpinned by a mathematical analysis of the controller model, is to search for good initial states, instead of optimising connection weights. Empirical validation in six different robot morphologies demonstrates that our method enables robots to learn primary locomotion skills in less than 15 minutes in the real world. In the end, we showcase our skills in a targeted locomotion experiment.

Wind Power Frequency Control in Doubly FED Induction Generator Using CFMPC-FOPID Controller Scheme

Because the majority of wind turbines operate in maximum output power tracking mode, power system frequency cannot be supported. However, if the penetration rate of wind power increases, the system inertia related to frequency modulation may decrease. In addition, frequency stability will be severely affected in the event of significant disturbances to the system load. Due to the high penetration of wind power in isolated power systems, this study suggests a coordinated frequency management approach for emergency frequency regulation. In order to prevent the phenomenon of load frequency control in doubly fed induction generators (DFIGs), a unique efficient control scheme is developed. The Cascaded Fractional Model Predictive Controller coupled with Fractional-Order PID controller (CFMPC-FOPID) is developed to provide the DFIG system with an efficient reaction to changes in load and system parameters. The proposed controller must have a robust tendency to respond quickly in terms of minimum settling time, undershoot, and overshoot. Nonlinear feedback controllers are designed using frequency deviations and power imbalances to achieve the reserve power distribution between generators and DFIGs in a variety of wind speed conditions. It makes upgrading quick and easy. In Matlab/Simulink, a simulation model is built to test the viability of the suggested approach.

Energy management system for AC/DC HMGS integrated with interconnected renewable sources and interlinking converter

AC/DC hybrid micro grid system (HMGS) is designed with renewable energy sources (RES) and battery energy storage system (BESS) with unique control schemes, interfaced with multi terminal interlinking converters (ILCs). This ILC operates on droop control scheme to guarantee bidirectional power sharing to AC/DC sub grids. The power sources in AC/DC sub grids like PV, Fuel cell, BESS are controlled by advance control methods for maximum power extraction with power quality. A three-level control structure is designed for optimal energy management system (EMS). The first level confirms the power balance in AC/DC sub grid with autonomous bidirectional power transfer via ILC in islanded mode. The second level tracks the batteries state of charge (SoC), based on the minimum and maximum SoC the battery operates for charging and discharging. The third level gives the power redundant capability for critical loads connected in AC/DC sub grid for DC system and single-phase system.

Energy-Saving Robust Saturated Control for Active Suspension Systems via Employing Beneficial Nonlinearity and Disturbance

This article proposes a novel control framework for active suspension systems by purposely employing beneficial nonlinearity and a useful disturbance effect for control performance enhancement. To this aim, a novel amplitude-limited PD-SMC control scheme is established to ensure a stable performance-oriented tracking control of the overall closed-loop system. Importantly, different from most existing control methods, the designed tracking controller purposely employs beneficial nonlinear stiffness and damping of a novel bioinspired reference model and deliberately utilizes useful disturbance response on the active suspension system, so as to improve the convergence speed and reduce control energy cost simultaneously. The asymptotic stability is theoretically proved by a rigorous Lyapunov-based analysis. To the best of our knowledge, this is a unique control scheme for active suspension systems which can technically take several critical control practice issues into account with guaranteed excellent performance simultaneously, including energy savings, actuator saturation, unexpected disturbances, etc. The superior performance is well validated with a series of experiments, and carefully compared to several existing control methods. The results of this study would definitely present a unique insight and an alternative approach to active controller designs via exploiting beneficial nonlinear and disturbance effects for better control performance and lower energy cost simultaneously.

Anti-windup filtered second-order generalized integrator-based spontaneous control for single-phase grid-tied solar PV-H2/Br2 redox flow battery storage microgrid system

Photovoltaic (PV) sources are increasingly deployed as distributed generators in remote single-phase utility grids. Meanwhile, variable power demand and fluctuating PV power output pose a challenge to utility grid stability and consistent power supply. This article introduces a hydrogen/bromine (H2/Br2) redox flow battery (RFB) for a single-phase grid-integrated PV system. A unique spontaneous control scheme for a single-phase two-stage grid-connected PV-H2/Br2 RFB system is proposed using an orthogonal signal generator-anti-windup filtered second-order generalized integrator (OSG-AWFSOGI) and tilt integral derivative (TID) controller. The OSG-AWFSOGI extracts the fundamental component from the grid voltage, even when the grid voltage is characterized by under-voltage, over-voltage, severe harmonics distortion, and other uncertain conditions. The TID controller is also used to regulate the DC-link voltage and current of the H2/Br2 RFB under various disturbances and dynamic conditions to deal with system fluctuation and prevent further degradation of the voltage quality. The control architecture also incorporates a feed-forward component to provide a quick dynamic response. Furthermore, a new sparrow search optimization algorithm is used to fine-tune the controller parameters for optimum TID control action. A battery control scheme is developed to control the H2/Br2 RFB to smooth the PV output and boost system operation planning, resiliency, and efficiency by providing short response time, rapid regulation, and voltage support. An incremental conductance-voltage current control (INC-VCC) maximum power point tracking (MPPT) system is proposed, with VCC based on a TID controller for rapid PV MPPT under solar irradiation changes and unexpected grid disturbance conditions. The proposed control is modelled and simulated in Matlab and verified using the OPAL-RT real-time simulator test bench. During simulation and testing, irradiance and temperature variations on PV array, load perturbation, over voltage, under voltage in grid voltage, and different complex disturbances and dynamic conditions are considered. Also, in comparison results, the proposed strategy outperformed compared to state-of-the-art approaches.

Exploring Transfers between Earth-Moon Halo Orbits via Multi-Objective Reinforcement Learning.

Multi-Reward Proximal Policy Optimization, a multi-objective deep reinforcement learning algorithm, is used to examine the design space of low-thrust trajectories for a SmallSat transferring between two libration point orbits in the Earth-Moon system. Using Multi-Reward Proximal Policy Optimization, multiple policies are simultaneously and efficiently trained on three distinct trajectory design scenarios. Each policy is trained to create a unique control scheme based on the trajectory design scenario and assigned reward function. Each reward function is defined using a set of objectives that are scaled via a unique combination of weights to balance guiding the spacecraft to the target mission orbit, incentivizing faster flight times, and penalizing propellant mass usage. Then, the policies are evaluated on the same set of perturbed initial conditions in each scenario to generate the propellant mass usage, flight time, and state discontinuities from a reference trajectory for each control scheme. The resulting low-thrust trajectories are used to examine a subset of the multi-objective trade space for the SmallSat trajectory design scenario. By autonomously constructing the solution space, insights into the required propellant mass, flight time, and transfer geometry are rapidly achieved.

Switching logic-based saturated tracking control for active suspension systems based on disturbance observer and bioinspired X-dynamics

In this paper, by deliberately introducing beneficial nonlinear stiffness and damping characteristics and employing beneficial disturbance effects, a unique switching logic-based saturated tracking control (SLSTC) scheme is proposed for active suspension control. Different from exiting robust control methods, the designed controller switches its structure to cancel out or retain the disturbance based on a novel well-designed disturbance effect indicator; and also, the inherent nonlinearity would be employed instead of directly cancelled by following the introduced bioinspired X-dynamics. The proposed SLSTC method could be for the first time to establish a deliberate assessor on the disturbance effect, and then to make full use of its positive response. These special designs are shown to be very beneficial for improving transient control response and saving control energy significantly. Experimental results validate that, the designed tracking controller can have obvious transient performance improvement up to 63% or more and save the control energy up to 51% or more, compared to traditional controllers. The results of this study would present a novel “robust and green” insight into active suspension control of vehicles by exploiting nonlinear benefits and disturbances.

Bioinspired Nonlinear Dynamics-Based Adaptive Neural Network Control for Vehicle Suspension Systems With Uncertain/Unknown Dynamics and Input Delay

A unique adaptive neural network control scheme is proposed for active suspension systems by employing bioinspired nonlinear dynamics, so as to address several critical engineering issues including energy efficiency, input delay, and unknown/uncertain dynamics simultaneously. A novel constructive predictor is firstly designed to solve the effect of input delay. Neural networks are then adopted to approximate the uncertain/unknown dynamics, and importantly, a unique finite-time adaptive control is established which can not only online update the input and output weights of the neural networks but also intentionally introduce beneficial nonlinear dynamics to vibration control. The significant difference from most existing controllers lies in that the designed controller can effectively utilize beneficial nonlinear stiffness and damping characteristics of a novel bioinspired reference model and, thus, purposely achieve superior vibration suppression and obvious energy-saving performance simultaneously. Theoretical analysis and experimental results vindicate that the proposed controller can effectively suppress vibration with much more improved control performance and considerably reduced control energy consumption more than 44%. This should be for the first time to reveal both in theory and experiments that a superior suspension performance is achieved simultaneously with an obvious control energy saving, by employing beneficial bioinspired nonlinear dynamics, compared to most traditional control methods.

7-kV 1-MVA SiC-Based Modular Multilevel Converter Prototype for Medium-Voltage Electric Machine Drives

This article presents the design and development of a 7-kV dc bus, 1-MVA, 0–1000 Hz modular multilevel converter (MMC) prototype for high speed medium-voltage variable frequency drives. The system is designed based on 1.7-kV silicon carbide (SiC) mosfet s. First, the full in-depth design of the prototype is provided, including the submodules, arm inductors, and system integration. Then, the unique control scheme and the control hardware design are presented to achieve the full-frequency range operation. The power loss based on Si and SiC devices is analyzed. Finally, experimental results are presented to demonstrate the performance of both the SiC-based submodule and the full-scale MMC system. Compared with the traditional Si-based solution, the established SiC MMC can reduce the drive system volume by 75% and achieve 325% power density, and the peak energy efficiency reaches around 99.35%.

Performance Analysis of Phase Noise Cancellation by Asymmetric CMA for Realizing Affordable Coherent PON Transceivers

We investigate the performance of a phase noise cancellation proposal to overcome the inherent laser linewidth limitation that acts as a key limiting factor in realizing digital signal processing (DSP)-based optical coherent access systems. The proposed cancellation algorithm is evaluated and analyzed through both extensive simulations and experimental studies on coherent 20-Gbit/s quadrature phase-shift keying (QPSK) signals. The use of polarization control based on the constant modulus algorithm (CMA) eliminates the polarization interference, which is a primary factor impacting the cancellation of random phase noise. A unique polarization control scheme with asymmetric CMA is proposed in order to remove the singularity issue created by the standard CMA. Its performance is verified in simulations and experiments. Through experiments that emulate laser linewidth by a phase modulator, it is confirmed that the cancellation algorithm overcomes the inherent limitation on laser linewidth.

Integrated Traction/Charge/Air Compression Supply Using Three-Phase Split-Windings Motor for Electric Vehicles

High cost, no-ideal driving range, and charge time limit electric vehicle market share. Facing these challenges, an integrated motor drive/battery charger system has been proposed by Valeo. A further advancement, based on this system, is present in this paper; for the first time, the integration of traction, charging, and air-compressor supply modes is proposed and tested by real-time experimentation. This integrated system is expected to increase the vehicle component compactness and power, therefore potentially reducing the cost and battery charging time. An overall and unique control scheme is detailed to achieve the three main operating modes: traction, charging, and air-compressor supply modes. The real-time experimentation results show the system feasibility.

Unified Robot Control Scheme for Cooperative Motion, Autonomous Motion and Contact Reaction

While the majority of industrial manipulators currently in use only need to performautonomousmotion, future generations of cooperative robots will also have to execute cooperative motion and intelligently react to contacts. These extended behaviours are essential to enable safe and effective physical Human-Robot Interaction (pHRI). However, they will inevitably result in an increase of the controller complexity. This paper presents a single variable admittance control scheme that handles the three modes of operation, thereby minimizing the complexity of the controller. First, the adaptative admittance controller previously proposed by the authors for cooperative motion is recalled. Then, a novel implementation of variable admittance control for the generation of smooth autonomous motion including reaction to collisions anywhere on the robot is presented. Finally, it is shown how the control equations for these three modes of operation can be simply unified into a unique control scheme.

Two Paralleled Four Quadrant DC Chopper for Gradient Coil Magnetic Fields in MRI System

This paper presents a two-paralleled four quadrant DC chopper type PWM power conversion circuit in order to generate a gradient magnetic field in the Magnetic Resonance Imaging (MRI) system. This circuit has 8-IGBTs at their inputs/outputs to realize further high-power density, high speed current tracking control, and to get a low switching ripple amplitude in a controlled current in the Gradient Coils (GCs). Moreover, the power conversion circuit has to realize quick rise/fall response characteristics in proportion to various target currents in GCs. It is proposed in this paper that a unique control scheme can achieve the above objective DSP-based control system realize a high control facility and accuracy. It is proved that the new control system will greatly enlarge the diagnostic target and improve the image quality of MRI.

Global Analysis of Heat Shock Response in Desulfovibrio vulgaris Hildenborough

Desulfovibrio vulgaris Hildenborough belongs to a class of sulfate-reducing bacteria (SRB) and is found ubiquitously in nature. Given the importance of SRB-mediated reduction for bioremediation of metal ion contaminants, ongoing research on D. vulgaris has been in the direction of elucidating regulatory mechanisms for this organism under a variety of stress conditions. This work presents a global view of this organism's response to elevated growth temperature using whole-cell transcriptomics and proteomics tools. Transcriptional response (1.7-fold change or greater; Z >/= 1.5) ranged from 1,135 genes at 15 min to 1,463 genes at 120 min for a temperature up-shift of 13 degrees C from a growth temperature of 37 degrees C for this organism and suggested both direct and indirect modes of heat sensing. Clusters of orthologous group categories that were significantly affected included posttranslational modifications; protein turnover and chaperones (up-regulated); energy production and conversion (down-regulated), nucleotide transport, metabolism (down-regulated), and translation; ribosomal structure; and biogenesis (down-regulated). Analysis of the genome sequence revealed the presence of features of both negative and positive regulation which included the CIRCE element and promoter sequences corresponding to the alternate sigma factors sigma(32) and sigma(54). While mechanisms of heat shock control for some genes appeared to coincide with those established for Escherichia coli and Bacillus subtilis, the presence of unique control schemes for several other genes was also evident. Analysis of protein expression levels using differential in-gel electrophoresis suggested good agreement with transcriptional profiles of several heat shock proteins, including DnaK (DVU0811), HtpG (DVU2643), HtrA (DVU1468), and AhpC (DVU2247). The proteomics study also suggested the possibility of posttranslational modifications in the chaperones DnaK, AhpC, GroES (DVU1977), and GroEL (DVU1976) and also several periplasmic ABC transporters.

Parallel Operation of Full-Bridge Power Amplifiers and Its Digital Optimal Control Scheme for Ultrahigh-Speed Scanning MRI

In recent years, MRI (Magnetic Resonance Imaging) systems have been actually requested to diagnose the moving parts of a human body such as the heart or the blood in angiography, where images should be taken in milliseconds instead of minutes. The gradient power supplies which are small but vital components for advanced MRI require higher output power capability as well as faster rise/fall dynamic response characteristics under a variety of specified current reference signals.This paper presents a novel switch-mode gradient power amplifier using IGBTs which is connected in parallel with the conventional 4-switch full-bridge power conversion circuits at their inputs/outputs in order to realize further high-power density. To satisfy the design specifications which require minimized the ripple and improved the rise/fall dynamic response characteristics of the current in the gradient coil, a unique digital control scheme on the basis of optimal preview type-1 servo system is proposed and described in detail. The above effectiveness is discussed and evaluated through the computer-aided analysis. It is expected that the proposed techniques will highly enlarge the diagnostic target and improve the image quality of ultrahigh-speed scanning MRI.

Case history: Catalytic system abates VOCs and NOx

AbstractThe standard technologies of Catalytic Oxidation and Selective Catalytic Reduction (SCR) are uniquely applied in a hybrid catalytic system that simultaneously destroys Volatile Organic Compounds (VOCs) and Oxides of Nitrogen (NOx) to fit the special circumstances of an extruded plastic foam manufacturing application.VOCs and NOx a re byproducts of extruded plastic foam manufacturing, generated in the curing ovens. For years, catalytic oxidation systems have been successfully used for the abatement of oven exhaust, containing VOC, NOx, nitrogen‐bearing compounds, and ammonia in varying ratios. In this application, because of the presence of ammonia in the manufacturing process, this single, skid‐mounted system uses a unique control scheme to achieve performance, while eliminating the need for ammonia injection and associated NOx analyzers, considered the standard for most SCR systems.System design features, function, and performance objectives will be explained in the context of the application. Catalyst requirements and selection will be detailed. Measure demission data will also be presented.

Parallel operation of four-switch full-bridge power amplifiers and a unique digital control scheme for advanced magnetic resonance imaging

In recent years, magnetic resonance imaging (MRI) systems have been in demand to diagnose moving parts in the human body such as the heart or the blood in angiography, where images should be taken in milliseconds instead of minutes. Gradient power amplifiers, which are small but vital components for advanced MRI, require higher output power capacity as well as faster rise/fall dynamic response characteristics under a variety of specified current reference signals. This paper presents a novel switch-mode gradient power amplifier using IGBTs which are connected in parallel to a conventional four-switch full-bridge power conversion circuit at their inputs/outputs in order to realize a higher power density. To satisfy the design specifications, which require minimized ripple and improved rise/fall dynamic response characteristics of the current in the gradient coil, a unique digital control scheme based on an optimal type 1 servo system is proposed and described in detail. The effectiveness of the above is discussed and evaluated through computer-aided analysis. It is expected that the proposed techniques will greatly expand the diagnostic targets and improve the image quality of MRI. © 2000 Scripta Technica, Electr Eng Jpn, 132(1): 64–72, 2000

Parallel operation of four-switch full-bridge power amplifiers and a unique digital control scheme for advanced magnetic resonance imaging

Parallel operation of four-switch full-bridge power amplifiers and a unique digital control scheme for advanced magnetic resonance imaging

高磁場MRI用大容量並列形スイッチング電源とそのディジタル制御方式の検討

高磁場MRI用大容量並列形スイッチング電源とそのディジタル制御方式の検討

A Multivariate Quality Control Scheme

Three functions are identified and integrated into one unique control scheme for multivariate quality control. The control scheme will identify any out‐of‐control samples, select the subset of variables that are out of control, and diagnose the out‐of‐control variables. New control variable selection algorithm and diagnosis methods are proposed and a framework for the control scheme is developed based on simulation results.