Control System Architecture Research Articles

Coordinated wind power plant and battery control for active power services

This article considers joint active power control of wind turbines and battery storage to follow a plant-level power reference signal. The joint control dynamically curtails the energy from a subset of the wind turbines and stores or withdraws energy from the battery to meet the power reference setpoint while accounting for wind plant aerodynamic interactions, such as wake losses. As a use case, we study the performance of the controller in maintaining a constant power output over hourly periods. A wind plant operating in this way would rely much less on other grid resources to meet its contractual agreements, thereby improving grid reliability, especially in grids with high penetration of wind and solar generation. We compare the operation of the wind plant under joint active power control to standard power-maximizing control with battery support. We present an analysis of the performance of the control system architecture. To study the impact of the battery size on performance, we simulate a 50-MW wind plant supported by batteries ranging from 8 to 64 MWh. We then evaluate the over and undergeneration penalties incurred by the plant during the simulation period.

A Multi-Robot-Based Architecture and a Trust Model for Intelligent Fault Management and Control Systems

One of the most important challenges in robotics is the development of a Multi-Robot-based control system in which the robot can make intelligent decisions in a changing environment. This paper proposes a robot-based control approach for dynamically managing robots in such a widely distributed production system. A Multi-Robot-based control system architecture is presented, and its main features are described. Such architecture facilitates the reconfiguration (either self-reconfiguration ensured by the robot itself or distributed reconfiguration executed by the Multi-Robot-based system). The distributed reconfiguration is facilitated through building a trust model that is based on learning from past interactions between intelligent robots. The Multi-Robot-based control system architecture also addresses other specific requirements for production systems, including fault flexibility. Any out-of-control fault occurring in a production system results in the loss of production time, resources, and money. In these cases, robot trust is critical for successful job completion, especially when the work can only be accomplished by sharing knowledge and resources among robots. This work introduces research on the construction of trust estimation models that experimentally calculate and evaluate the trustworthiness of robots in a Multi-Robot system where the robot can choose to cooperate and collaborate exclusively with other trustworthy robots. We compare our proposed trust model with other models described in the literature in terms of performance based on four criteria, which are time steps analysis, RMSD evaluation, interaction analysis, and variation of total feedback. The contribution of the paper can be summarized as follows: (i) the Multi-Robot-based Control Architecture; (ii) how the control robot handles faults; and (iii) the trust model.

A Microservices-Based Approach to Designing an Intelligent Railway Control System Architecture

The symmetry between customer expectations and operator goals, on one hand, and the digital transition of the railways, on the other hand, is one of the main factors affecting green transport sustainability. The European Train Control System (ETCS) was created to improve interoperability between different railway signaling systems and increase safety and security. While there are a lot of ETCS Level 2 deployments all over the world, the specifications of ETCS Level 3 are under development. ETCS Level 3 is expected to have a significant impact on automatic train operation, protection, and supervision. In this paper, we present an innovative control system architecture that allows the incorporation of artificial intelligence (AI)/machine learning (ML) applications. The architecture features control function virtualization and programmability. The concept of an intelligent railway controller (IRC) is introduced as being a piece of cloud software responsible for the control and optimization of railway operations. A microservices-based approach to designing the IRC’s functionality is presented. The approach was formally verified, and some of its performance metrics were identified.

Research on Logic Design of Proton Treatment Control System

The proton treatment control system is the supporting software of the proton therapy device, which specifically coordinates and controls the status and work of each subsystem. In this study, the software architecture and hardware implementation of the proton treatment control system was developed and built a foundation for the overall debugging. Using C# programming language and WPF programming techniques, TCP network communication protocol specified by the proton treatment technical document and MVVM pattern in Windows system, the logic design and implementation of each level were studied. Meanwhile, the communication interface between the subsystems under TCP communication protocol was agreed. The logic design and research of the setup field and treatment field were carried out. And the User Interface was designed and developed using the above technology. The program realizes the communication and interaction between the proton treatment control system and each subsystem, so as to control and monitor the whole treatment process. The proton treatment control system provides a software basis for the remote overall debugging and on-line monitor and control of proton treatment device.

Switching tube model predictive based controller design for multi‐agent unmanned aerial vehicle system with hybrid topology

AbstractThe decentralized control is provided for the multi‐agent unmanned aerial vehicle system and is designed based on leader‐follower configuration by graph theory. Next, primary model predictive control (MPC) is proposed in order to steer the error signal to the origin and specifically, an optimization algorithm is considered for the primary MPC controller in which the Newton optimization with back‐stepping step size definition is proposed for this manner. A robust modification is investigated for the system based on tube definition and considered to overcome the high‐frequency noise and external disturbances in a bound of 20% of the system output. The high‐frequency noises are designed outside of the primary controller band‐width. The hybrid controller is proposed for the system. The closed‐loop swarm system's control architecture, switches between the primary MPC controller to tube‐MPC controller in the presence of high‐frequency noises and external disturbances. The hybrid controller provides a more energy‐efficient outcome compared to the single mode controller. The final results provides a 7% faster simulation time. Afterward, the flexible formation theory is generalized for system. The possibility of changing leader is investigated in flexible formation and a scenario of switching leader is proposed for the system. The result of tracking for the controller is compared to proportional‐integral‐derivative and the problem of four agents in a flight scenario illustrates the issues and the comparison between the robust controller and the switching Tube‐MPC controller is provided. The results provide that the novel control architecture has a 47.6% lower rise time and 30.8% lower overshoot.

An extendable maneuver management framework with fault‐tolerant mechanism for vehicle platoon control system in highway scenario

AbstractVehicle platoons can encounter many complex scenarios in practice that were not considered in the design, which reveals the need to add new maneuvers. Platoon control system will face the challenge of the lack of maneuver scalability in practical applications. To address this problem, this study introduces an extendable maneuver management framework with fault‐tolerant mechanism on the basis of the hierarchical architecture for the platoon control system. Maneuvers and roles are two dimensions, based on which the management strategies are decoupled. They enable each vehicle in the platoon to execute management strategies of various maneuvers and make it possible to expanding new behaviors into existing strategies. The fault‐tolerant mechanism is designed as a maneuver triggered by hardware failures to remain safe before taking over. Furthermore, three typical maneuvers are selected for case studies to illustrate the management strategies in this framework. Finally, a comprehensive simulation scenario integrating different maneuvers is designed and a real‐world implementation using micro‐vehicles is conducted. The results demonstrate that the proposed two‐dimensional framework could effectively address various maneuvers and satisfy the computational real‐time requirements.

A dual robust control architecture with variable stiffness and damping parameters for switching task dominance in collaborative haptic systems

AbstractIn collaborative haptic training systems, a novice operator is interfaced with an expert operator and cooperatively performs some task on a real/virtual environment. Most control architectures for collaborative haptic training systems do not consider the switching task dominance together with investigating overall stability in the presence of nonlinear dynamics and uncertainty. In this paper, a theoretical framework is presented for switching task dominance in collaborative haptic training systems based on supervision and intervention of the expert operator. To that effect, the novice operator performs the operation with as little as possible interference haptic signals in the normal operational conditions. On the other hand, the expert operator is able to intervene the operation to guide the novice operator when it is necessary. The most challenging part of controller design for such systems is to provide the mentioned supervisory framework in a way that the stability of interaction between the operators and the system is ensured with acceptable task performance in various operational conditions. This work offers a variable‐gain dual robust control scheme to address the above problem. The key idea is that the tracking gain of each controller is adjusted in real‐time to switch the task authorities. It is verified that the input‐to‐state stability property is satisfied for each subsystem. Then, the overall stability is proved by leveraging the small gain theorem. Finally, the functionality and performance of the suggested control architecture is demonstrated through simulation and experimental studies.

Redundant architecture design and Human-machine system analysis of active side stick control system

This paper describes the advantages and disadvantages and principle of passive side stick and active side stick respectively. A redundant architecture of active side stick control system is proposed according to top-level function and safety requirements. The control unit with active-standby control channels, which has dissimilar command-monitoring hardware, can significantly improve the safety performance. Finally, the high angle of attack protection and high-speed protection of active side stick control system has been tested on one civil aircraft simulation platform, and it proves that the active side stick control system can effectively realize the tactile and warning function of envelope protection.

Model predictive real-time architecture for secondary voltage control of microgrids

The integration of new elements and technologies to the power grid, driven by the expansion of electric microgrids, brings various challenges requiring a suitable control architecture for systems to operate ensuring economic and reliable access to electricity. This paper presents the development of a time-varying constraint real-time model predictive secondary voltage control (MPVC) strategy for microgrids built up in a multi-class Python environment with InfluxDB and SQLExpress databases storing the controller and microgrid data, and its experimental implementation with Modbus communication to physical devices at the Universidad Pontificia Bolivariana (UPB) campus microgrid. The microgrid characteristics are described and the experimental setup is presented. The mathematical model of the resource used as case study is obtained through experimental identification, and it is integrated to the MPVC scheme. Polytopic invariant sets are used as terminal sets in the MPVC scheme to ensure stability of the solution, and time-varying constraints of reactive power availability are considered. Validation studies of the proposed control system in computational simulation are presented prior to real application in the UPB campus microgrid. Controller performance results are described for three different implementation scenarios of low, medium and high variability of external disturbances, presenting adequate voltage regulation around the reference value and considerable dependence on the meteorological forecast quality. The model predictive voltage controller is finally benchmarked against a commercial microgrid controller to evaluate its performance, standing out as a more comprehensive and tailor-made solution.

Development and Evaluation of a Unified Integrated Platoon Control System Architecture

Vehicle platooning has become a topic of substantial interest for development of safer and more efficient means of transportation. It is described as a string of connected autonomous vehicles traveling closely, maintaining certain inter-vehicular distances at a set speed boosting the road capacity, improving safety and lowering adverse environmental significance. In this study, several platooning concepts addressed in previous literature are revealed. A unified integrated platoon control architecture is constructed, employing the aforementioned concepts. This architecture contemplates a generic decoupled longitudinal and lateral engine-based vehicle model incorporating the powertrain dynamics. Several control algorithms are investigated, optimized and compared to manage the longitudinal inter-vehicular spacing distances of a formed platoon, as well as the lateral platoon motion tracking. The superior longitudinal controller in terms of spacing error convergence, velocity tracking and acceptable control effort, in addition to the outperformed lateral controller for its accurate lane change tracking and lower computational cost are promoted to be tested in the integrated architecture. Simulations are visualized using the Multi-Robot Systems Intelligent Transportation Systems (MRS-ITS) visualization tool for further realization of the results.

A high-reliability PV system by replacing electrolytic capacitors with film capacitors

Electrolytic capacitors are considered a vulnerable link in PV systems. In order to enhance the system reliability and lifespan, this paper investigates a PV system without electrolytic capacitors. First, the system structure is introduced. Then, the system control architecture based on the system structure of a bidirectional-DC/DC connecting to the dc-bus is proposed. Five control loops are illustrated for current ripple absorbing. Furthermore, an alternative control solution is proposed to eliminate four current sensors for reducing system costs. Meanwhile, a DC-bus voltage over-limit control block is added. Additionally, another alternative solution is proposed where a blocking unit is added. The blocking unit is activated only when the dc-bus voltage is over the limits to increase system efficiency. Finally, experimental results are provided to verify the theory.

Approximate Optimal Tracking Control for Partially Unknown Nonlinear Systems via an Adaptive Fixed-Time Observer

This paper investigates a novel adaptive fixed-time disturbance observer (AFXDO)-based approximate optimal tracking control architecture for nonlinear systems with partially unknown dynamic drift and perturbation under an adaptive dynamic programming (ADP) scheme. To attenuate the impact of disturbance, a novel AFXDO was designed based on the principle of a fixed-time stable system without prior information of disturbance, making disturbance observer errors converge to zero in a fixed time independent of initial estimation error. Additionally, approximate optimal control is conducted by incorporating the real-time estimation of AFXDO into a critic-only ADP framework to stabilize the dynamics of tracking errors and strike a balance between consumption and performance. In particular, to address the heavy calculation burden and oscillation phenomenon in the traditional actor–critic structure, an improved adaptive update law with a variable learning rate was developed to update the weight for adjusting the optimal cost function and optimal control policy simultaneously, avoiding the initial chattering phenomenon and achieving a prescribed convergence without resorting to dual networks. With the efforts of AFXDO and a weight law with a variable learning rate, the track errors were achieved with fast transient performance and low control consumptions in a fixed time. By revisiting Lyapunov stability, the tracking error and weight estimation error were proven to be uniformly ultimately bounded, and the designed control tended to optimal control. The simulations were carried out on quadrotor tracking to demonstrate the effectiveness of the developed control scheme, which achieves rapid convergence by lower control consumption in 4 s, where the cost function is reduced by 19.13%.

Study on the digitalization of trip equations including dynamic compensators for the Reactor Protection System in NPPs by using the FPGA

Advanced reactors, such as Small Modular Reactors or existing Nuclear Power Plants, often use Field Programmable Gate Array (FPGA) based controllers in new Instrumentation and Control (I&C) system architectures or as an alternative to existing analog-based I&C systems. Compared to CPU-based Programmable Logic Controllers (PLCs), FPGAs offer better overall performance. However, programming functions on FPGAs can be challenging due to the requirement for a hardware description language that does not explicitly support the operation of real numbers. This study aims to implement the Reactor Trip (RT) functions of the existing analog-based Reactor Protection System (RPS) using FPGAs. The RT equations for Overtemperature delta Temperature and Overpower delta Temperature involve dynamic compensators expressed with the Laplace transform variable, ‘s’, which is not directly supported by FPGAs. To address this issue, the trip equations with the Laplace variable in the continuous-time domain are transformed to the discrete-time domain using the Z-transform. Additionally, a new operation based on a relative value for the equation range is introduced for the handling of real numbers in the RT functions. The proposed approach can be utilized for upgrading the existing analog-based RPS as well as digitalizing control systems in advanced reactor systems.

Adaptive closed-loop resuscitation controllers for hemorrhagic shock resuscitation.

After hemorrhage control, fluid resuscitation is the most important intervention for hemorrhage. Even skilled providers can find resuscitation challenging to manage, especially when multiple patients require care. In the future, attention-demanding medical tasks like fluid resuscitation for hemorrhage patients may be reassigned to autonomous medical systems when availability of skilled human providers is limited, such as in austere military settings and mass casualty incidents. Central to this endeavor is the development and optimization of control architectures for physiological closed-loop control systems (PCLCs). PCLCs can take many forms, from simple table look-up methods to widely used proportional-integral-derivative or fuzzy-logic control theory. Here, we describe the design and optimization of multiple adaptive resuscitation controllers (ARCs) that we have purpose-built for the resuscitation of hemorrhaging patients. Three ARC designs were evaluated that measured pressure-volume responsiveness using different methodologies during resuscitation from which adapted infusion rates were calculated. These controllers were adaptive in that they estimated required infusion flow rates based on measured volume responsiveness. A previously developed hardware-in-loop test platform was used to evaluate the ARCs implementations across several hemorrhage scenarios. After optimization, we found that our purpose-built controllers outperformed traditional control system architecture as embodied in our previously developed dual-input fuzzy-logic controller. Future efforts will focus on engineering our purpose-built control systems to be robust to noise in the physiological signal coming to the controller from the patient as well as testing controller performance across a range of test scenarios and in vivo.

Implementation of a Hybrid Intelligence System Enabling the Effectiveness Assessment of Interaction Channels Use in HMI.

The article presents a novel idea of Interaction Quality Sensor (IQS), introduced in the complete solution of Hybrid INTelligence (HINT) architecture for intelligent control systems. The proposed system is designed to use and prioritize multiple information channels (speech, images, videos) in order to optimize the information flow efficiency of interaction in HMI systems. The proposed architecture is implemented and validated in a real-world application of training unskilled workers-new employees (with lower competencies and/or a language barrier). With the help of the HINT system, the man-machine communication information channels are deliberately chosen based on IQS readouts to enable an untrained, inexperienced, foreign employee candidate to become a good worker, while not requiring the presence of either an interpreter or an expert during training. The proposed implementation is in line with the labor market trend, which displays significant fluctuations. The HINT system is designed to activate human resources and support organizations/enterprises in the effective assimilation of employees to the tasks performed on the production assembly line. The market need of solving this noticeable problem was caused by a large migration of employees within (and between) enterprises. The research results presented in the work show significant benefits of the methods used, while supporting multilingualism and optimizing the preselection of information channels.

A Comparative Research of Control System Design Based on H-Infinity and ALQR for the Liquid Rocket Engine of Variable Thrust

The design and analysis procedures for the thrust controller used in variable-thrust rocket engines are substantially different from those used in conventional engines due to the large-scale thrust adjustment capabilities that result in a wide range of operating situations. In this study, two control algorithms, h-infinity and adaptive linear quadratic regulator (ALQR), are constructed, examined, and contrasted utilizing the adaptive control system architecture. Both methods are capable of producing engines that respond in less than one second, have a steady-state error of less than two percent, and are robust.

As built design of the control systems of the ITER full-size beam source SPIDER in the neutral beam test facility - A critical review

SPIDER, ITER's full-size beam source at the Neutral Beam Test Facility (NBTF), has been operational since 2018. SPIDER's mission is to optimize the operation of the beam source in order to reuse SPIDER's experience on MITICA, the full-size prototype of the ITER Neutral Beam Injector, and in the ITER injectors.The exploitation of SPIDER started with short, low-performance pulses lasting up to a few seconds and progressed to obtain long pulses up to 3000 seconds. Furthermore, the integration of plant and diagnostic systems has grown over time. The amount of data collected per pulse provide a measure of evolution: it has gone from a few tens of MB in the first campaign pulses to the current average value of over 130 GB, most of which produced by infrared and visible cameras. From the first operation onwards, the control systems have also evolved, including components and functions initially not foreseen or developed in a preliminary form. This includes the progressive integration of plant and diagnostic systems and of protection and safety functions.The paper initially focuses on the architecture of the SPIDER control systems, i.e. CODAS, the system delivering conventional control and data management, the central interlock system, delivering plant protection, and the central safety system delivering people and environment safety. Since we developed all systems according to the ITER guidelines for implementing control systems, the integrated SPIDER control, interlock and safety systems may provide an interesting example for developers of ITER plant systems. The paper then describes how the top-down definition and implementation of operating states and operational scenarios provides the framework for the integration of control, interlock and safety systems and the basic elements for successful operation. Finally, the paper reports the lessons learned during these years of operation with particular attention to the progressive, continuous evolution and recommissioning of systems.

Design and Suitability Analysis of FPGA-Based TCP/IP Offload Module for Control Systems of FBRs

Transmission Control Protocol/Internet Protocol (TCP/IP) offload modules play a crucial role in India’s first commercial fast breeder reactor (PFBR) distributed digital control system architecture by providing networking capabilities to the real-time control systems used in safety-critical and safety-related applications of the PFBR. These modules enable operators to remotely control various mechanisms, facilities, and process loops via real-time control systems from the main control room display stations. The malfunctioning of these modules may hamper the overall plant’s availability; hence to improve further upon safety, security, reliability, and performance, these modules have been indigenously developed for upcoming fast breeder reactors in India. This paper proposes methods to justify the suitability of these communication modules as per the D-25 design guidelines issued by the Atomic Energy Regulatory Board of India. The design and testing aspects are covered, including an approach toward hardware descriptive language-based design and testing with respect to the IEEE standard and the TCP/IP protocol specifications. Module design validation based on ethernet frame transactions is detailed in this paper. The test platform design, which includes the diagnostics software design for CPUs designed with these TCP offload modules, and the design of a graphical user interface to detect and record TCP connection anomalies are detailed. The network interface response to postulated events of TCP packet corruption, packet drop, packet delay, out-of-order packets, duplicate packets, and heavy traffic is characterized.

A Hybrid Systems-Based Hierarchical Control Architecture for Heterogeneous Field Robot Teams.

Field robot systems have recently been applied in a wide range of research fields. Further automation, development, and activation of such systems require cooperation among heterogeneous robots. Classical control theory is inefficient in managing large-scale complex dynamic systems. Therefore, a discrete-event system based on the supervisory control theory must be introduced to overcome this limitation. In this article, we propose a hybrid system-based hierarchical control architecture using a supervisory control-based high-level controller and a traditional control-based low-level controller. The hybrid system and its dynamics are modeled through a formal method, called hybrid automata, and the behavior specifications are designed to express the control objectives for cooperation. In addition, modular supervisors that are more scalable and maintainable than a centralized supervisory controller were synthesized. The proposed hybrid system and hierarchical control architecture were implemented, validated, and evaluated for performance through a physics-based simulator and field tests. The experimental results confirmed that the robot team satisfied the given specifications and presented systematic results, validating the efficiency of the proposed control architecture.

A novel hydraulic load-sensing control solution to working functions of mobile machine

The hydraulic load-sensing system is a more efficient system solution than constant pressure system in mobile machine. However, the overall system efficiency for multiple actuators is still low since this centralized hydraulic control system only adapts to the highest load pressure. Therefore, in this article, a distributed hydraulic control system where each function is powered by a hydraulic free piston engine is proposed. Compared with centralized solution, it is more efficient since the power of hydraulic free piston engine is tailored to each function. By integrating small inertia linear engine and pump piston in one unit, the hydraulic free piston engine is an efficient and fast response hydraulic power source. Since the hydraulic free piston engine is essentially a digital hydraulic power source, a digital load-sensing control is proposed in this study. The system architecture, modeling, controller design and performance of the digital hydraulic load-sensing control system are presented. A test bench is developed to verify the system feasibility and performance.