Control Structure Design Research Articles

Water surface profile prediction in non-prismatic compound channel using support vector machine (SVM)

The process of estimating the level of water surface in two-stage waterways is a crucial aspect in the design of flood control and diversion structures. Human activities carried out along the course of rivers, such as agricultural and construction operation, have the potential to modify the geometry of floodplains, leading to the formation of compound channels with non-prismatic floodplains, thus possibly exhibiting convergent, divergent, or skewed characteristics. In the current investigation, the Support Vector Machine (SVM) technique is employed to approximate the water surface profile of compound channels featuring narrowing floodplains. Some models are constructed by utilizing significant experimental data obtained from both contemporary and previous investigations. Water surface profiles in these channels can be estimated through the utilization of non-dimensional geometric and flow parameters, including: converging angle, width ratio, relative depth, aspect ratio, relative distance, and bed slope. The results of this study indicate that the SVM-generated water surface profile exhibits a high degree of concordance with both the empirical data and the findings from previous research, as evidenced by its R2 value of 0.99, RMSE value of 0.0199, and MAPE value of 1.263. The findings of this study based on statistical analysis demonstrate that the SVM model developed is dependable and suitable for applications in this particular domain, exhibiting superior performance in forecasting water surface profiles.

Design and implementation of a state-space controller for an air pressurization plant with slow dynamics and output delay

This paper presents the design of a servo-integrator type state-space digital control structure for an air pressurization plant. The plant is characterized by slow dynamics with output delay. To evaluate the performance of the servointegrator controller, two control structures, namely, STR-PID and conventional PID are tuned and implemented. With the results obtained, a comparative analysis is performed based on metrics related to time response and control effort. At the end, it is evidenced that the Servointegrator type state space controller outperformed the other two controllers, demonstrating that it is an effective strategy that allows controlling systems with slow dynamics and dead time in the output.

TMD Design by an Entropy Index for Seismic Control of Tall Shear-Bending Buildings.

This study proposes a new arrangement-tuning method to maximize the potential of tuned mass dampers (TMDs) in decreasing the seismic responses of tall buildings. The method relies on a Grammian-based entropy index with the physical meaning of covariance responses to white noise without the involvement of external inputs. A twelve-story RC frame-shear wall building was used as an example to illustrate the method. Indices were computed for the building with TMDs placed on different stories and tuning to different modes and were compared with responses to white noise (colored) time histories. Results showed that greater index reduction cases agree well with greater story-drift reductions cases, despite the differences in the time step of the white noises and structural model types (pure shear vs. shear-bending), and the optimal TMD is not necessarily the traditional "roof-1st mode tuning" case. Comparisons were also made for the shear-bending building under seven earthquake excitations. It is found that, though TMDs are not full-band effective controllers, the index-selected TMDs still perform the best in three out of seven earthquakes. So, the proposed internal-property-based entropy index provides a good controller design for large-scale structures under unpredictable none-stationary excitations.

State machine-based architecture to control system processes in a hybrid fuel cell electric vehicle

This paper presents the development and implementation of a system supervisory controller in a hydrogen-based fuel cell electric vehicle. The controller's primary function is to ensure the safe control of the fuel cell system processes while facilitating coordination among various subsystems, including the balance of plant subsystems, vehicle control unit, diagnosis unit, and powertrain. The supervisory controller comprises of three primary parts: a State Machine, an Optimal Setpoint Generator, and a Power Limit Calculator. The State Machine, which serves as the central part of the supervisory controller, coordinates the fuel cell system's different operational states, including the complex processes of start-up and shutdown. To maximize the fuel cell system's efficiency and minimize the stack's degradation, the Optimal Setpoint Generator produces the subsystem's setpoints by solving an optimization problem and considering the manufacturer's requirements. The Power Limit Calculator assesses the stack's power output capability and calculates the current setpoint for the DC/DC converter. It then provides this data to the Energy Management System (EMS), which oversees the distribution of power between the fuel cell system and the batteries. The proposed fuel cell system supervisory controller is verified using the Worldwide Harmonized Light Vehicles Test Cycles (WLTC) in a real-world car. The designed control structure is implemented in a prototype hydrogen-based electric car at both PowerCell and CEVT facilities under the framework of the INN-BALANCE Horizon 2020 European project.

Investigations on the Diesel Spray Characteristic and Tip Penetration Model of Multi-Hole Injector with Micro-Hole under Ultra-High Injection Pressure

Increasing the injection pressure has a significant impact on atomization and combustion characteristics. Spray tip penetration serves as a vital parameter for fuel injection control and engine structure design. However, a reliable spray tip penetration model for ultra-high-pressure injection is currently lacking. To address this gap, this study establishes a theoretical 0-dimensional model for spray tip penetration under ultra-high pressure (300 MPa) conditions. The model is based on the conservation of momentum and phenomenological models. The new model divides spray tip penetration into two stages: Pre-breakup and post-breakup, with fuel injection rate and spray cone angle used as model inputs. To validate the model, high-speed camera observations and constant-volume chamber experiments are conducted to investigate the spray characteristics. The results indicate that the new spray tip penetration model demonstrates improved predictive accuracy across all experimental conditions.

Side-Chain-Dependent Functional Intercalations in Graphene Oxide Membranes for Selective Water and Ion Transport.

Subnanometer interlayer space in graphene oxide (GO) laminates is desirable for use as permselective membrane nanochannels. Although the facile modification of the local structure of GO enables various nanochannel functionalizations, precisely controlling nanochannel space is still a challenge, and the roles of confined nanochannel chemistry in selective water/ion separation have not been clearly defined. In this study, macrocyclic molecules with consistent basal plane but varying side groups were used to conjunct with GO for modified nanochannels in laminates. We demonstrated the side-group dependence of both the angstrom-precision tunability for channel free space and the energy barrier setting for ion transport, which challenges the permeability-selectivity trade-off with a slightly decreased permeance from 1.1 to 0.9 L m-2 h-1 bar-1 but an increased salt rejection from 85% to 95%. This study provides insights into the functional-group-dependent intercalation modifications of GO laminates for understanding laminate structural control and nanochannel design.

Location and Design of Flow Control Structures Differentially Influence Salinity Patterns in Small Artificial Drainage Systems

Saltwater intrusion is a pervasive threat to coastal ecosystems. Common management strategies entail the installment of engineered flow control structures, though there is a dearth of work on their prevalence across the landscape and how different structures impact salinity under various hydrologic conditions. We manually classified more than 900 structures with most either being culvert pipes or riser structures. We then investigated how these structures impacted salinity in surface waters after the landfall of Hurricane Florence in 2018 and during the Summer of 2020. To accomplish this, we combined longitudinal and depth surveys, with long-term monitoring of salinity up and downstream of three flow control structures. Our results reveal that a flow control structure’s ability to exclude or trap saltwater from/in upstream environments depends on its position inland and design. Engineered structures were effective at excluding saltwater, while unintentional structures sometimes trapped saltwater in upstream environments. This work sheds light on important factors land managers should consider when putting in place new structures for freshwater management purposes.

Branch Unit Distribution Matters for Gene Delivery.

As a key nonviral gene therapy vector, poly(β-amino ester) (PAE) has demonstrated great potential for clinical application after two decades of development. However, even after extensive efforts in structural optimizations, including screening chemical composition, molecular weight (MW), terminal groups, and topology, their DNA delivery efficiency still lags behind that of viral vectors. To break through this bottleneck, in this work, a thorough investigation of highly branched PAEs (HPAEs) was conducted to correlate their fundamental internal structure with their gene transfection performance. We show that an essential structural factor, branch unit distribution (BUD), plays an important role for HPAE transfection capability and that HPAEs with a more uniform distribution of branch units display better transfection efficacy. By optimizing BUD, a high-efficiency HPAE that surpasses well-known commercial reagents (e.g., Lipofectamine 3000 (Lipo3000), jetPEI, and Xfect) can be generated. This work opens an avenue for the structural control and molecular design of high-performance PAE gene delivery vectors.

Structure Optimization and Control Design of Electronic Oxygen Regulator

The oxygen regulator is the core component of the aircraft life support system, which adjusts the flow and pressure of the breathing gas according to the pilot’s breathing needs. In response to the problem that structural parameters are difficult to adjust and prone to jitter when the indirect oxygen regulator system is stable, a direct oxygen regulator is designed using a stepper motor to drive a lung-type flapper, replacing the diaphragm lever-type structure of the indirect oxygen regulator. Due to the nonlinearity and time-varying nature of the dynamic characteristics of oxygen regulators, a single-neuron PID control strategy based on online identification of RBF neural networks is proposed to improve the PID control performance. The RBF neural network is used to identify the Jacobian information of the controlled object, and the single-neuron PID controller completes the online adjustment of the controller parameters to realize the intelligent control of the system. Simulation experimental studies are conducted to verify the performance of the direct oxygen regulator. The result analysis verifies the excellence of the single-neuron PID control strategy based on online recognition of the RBF neural network to improve the system performance.

Improved Three-Variable Control for Electromagnetic Mass Damper System Considering Control–Structure Interaction

Current methods account for control–structure interaction (CSI) in structural control design, which may be unavailable in the preliminary design phase of actively controlled structures due to the unknown dynamic characteristic of an actuator. Therefore, it may result in significant difference in the design and evaluation of an active structural control system when ignoring or considering CSI at different phases. To eliminate the CSI effects of electromagnetic mass damper (EMD) system and thus decouple the tracking control of EMD from the control design of structure, in this paper, an improved three-variable control (ITVC) combining a signal convertor, a typical three-variable controller, and a voltage compensator is developed. The voltage compensator counteracts the influence of lower-order CSI including viscous damping force and Coulomb friction. The three-variable controller reduces the higher-order CSI effects, while the signal convertor converts all command and feedback signals to the relative coordinate system and eliminates the additional CSI effects. Performance tests and frequency response tests of the EMD system show that the CSI effects are basically eliminated by ITVC. In addition, shake table tests are performed on a one-story actively controlled structure to further verify ITVC. Experimental results suggest that ITVC can apply accurate control force on the structure and achieve ideal structural response control.

Approach to multi-disaster risk assessment and policy recommendation for disaster resilient urban development: A study of Birgunj–Simara Corridor

This study identified multiple nature of disasters in Tarai in general and Birgunj - Simara Urban Corridor, one of the hotspots of urbanization in Nepal in particular. Using geospatial technology, secondary sources of information, and stakeholder’s consultations, this study evaluated floods, earthquakes, windstorms, and fire impacts, identified factors contributing to vulnerability, and solutions for increasing resilience. Although rivers have limited floodplains, floods have been increased because of floodplain encroachment, improper drainage, land use changes in upper catchment, and climate change. Although the earthquake could have a high impact, the seismicity is low compared to the national context. During pre- and monsoon seasons, windstorms have a high impact over a limited area and are hard to predict. Fires are not widespread in the settlements but common during hot, dry months due to compact rural settlements, nonresilient house designs, and inadequate safety measures. Besides, lack of adaptation capacity as a result of poor awareness, widespread poverty, and poor disaster response have contributed to a high vulnerability to multihazards. Mitigation actions identified include risk-sensitive land use planning, flood control and hydraulic structure design, efficient urban drainage, waste management, resilient housing, and disaster safety plans. Local communities should be involved in developing early warning systems, disaster preparedness, and response measures.

A composite control scheme for electromagnetic active mass damper against control-structure-interaction effects

Existing methods account for control-structure-interaction (CSI) in structural control design. However, their implementations may be challenging since the dynamic characteristics of actuator are unavailable in the preliminary design phase of actively controlled structures. In this study, a composite control scheme (CCS) is proposed to eliminate the CSI effects of electromagnetic active mass damper (AMD), and thus decouple the tracking control of AMD from the control design of structure. In the CCS, force compensation is performed to counteract the influence of lower-order CSI including the damping force and friction, while hierarchical control comprised of low-level feed-forward/feedback control and high-level sliding mode control is designed to reduce the higher-order CSI effect and achieve a high-performance force control. Performance tests and frequency response tests of the electromagnetic AMD system indicate that the CSI effects are significantly reduced by the proposed CCS. Furthermore, shake table tests are conducted on a two-story actively controlled structure to verify the effectiveness of CCS. Experimental results show that the proposed CCS can apply accurate control force to the structure, which contributes to an ideal structural response control.

Cyclomatic Complexity dan Graph Matrix dalam Pengujian Sistem Informasi Manajemen Rumah Sakit

Information systems can assist hospital management in improving services at a hospital. The software development method used in making hospital management applications is using the waterfall method which one of the stages is testing. The problem in system development is that the testing process is not optimal and focuses more on system development so that errors can be found at the implementation stage. System testing is a permit for an error in the system being developed. The aim of the research is to check the design details, use the program design control structure procedurally and run the program to find errors. The method applied to carry out the testing phase in the hospital management system is the Whitebox method using the cyclomatic complexity and graph matrix approaches. Testing will be carried out on the process of managing inpatient data in the application. The results of the research from testing the hospital management system using the cyclomatic complexity approach are that it can provide information on the minimum number of tests and ensure that all program structure paths are used at least once. In addition, the results of the graph matrix test are the probability side that will be carried out.

Performance-based active controller design for nonlinear structures using modified black hole optimization

This paper presents a novel approach that facilitates the design of active controllers to mitigate seismically induced damage in structural systems. The proposed method is based on stochastic Modified Black Hole optimization algorithm. Two traditional controllers, namely Proportional-Integral-Derivative (PID) and Linear–Quadratic Gaussian (LQG) controllers were designed, and their performance was demonstrated on a benchmark 20-story steel-framed building. Evaluation criteria were defined to satisfy constraints on various response quantities, including drift, base shear, ductility, residual story drift, and control force. The constraint limits were defined in view of performance-based design requirements for the benchmark structure. The performance of the controllers was contrasted with that of traditional LQG, and significant reductions of all response quantities were achieved for design-level earthquakes.

Knowledge-based integrated optimization design of agile imaging satellites' attitude controller and vibration isolator

The integrated design of modern agile imaging satellites' systems demands multidisciplinary optimization to ensure the satisfaction of image quality and acquisition efficiency requirements. Beyond the scope of traditional integrated design methods that optimize parameters, the policy to vary parameters over time is required to be optimized especially for changing environments and objectives. Though modern optimization methods provide powerful tools, knowledge about the dynamic system is indispensable to guarantee credibility for truly intelligent integrated design. This paper proposes an integrated control and structural optimization design scheme to optimize variables of the full control-structure system in order to meet conflicting constraints on the attitude control stability requirement and the vibration isolation requirement. To reduce the workload of the iterative design, a safe reinforcement learning algorithm is proposed to learn the time-varying parameters of the camera's vibration isolator and the attitude controller. Our design philosophy is to combine priori knowledge about the non-collocation control stability into the reinforcement learning optimization to safely optimize the control-structure design. The constraint satisfaction is achieved with an improved safety layer technique applied to the output policy of the reinforcement learning agent, which solves a nonlinear constraint programming problem to timely confine learned parameters. We exemplify the proposed method on a push-broom imaging case and a backward-forward slewing case, successfully optimizing the effective imaging time under constraints.

Enhanced control structure design for an industrial off-gas system: Simple reconfigurations benefit the economy

For control structure design of the industrial off-gas benchmark system, application of the Skogestad's state-of-art design procedure has suggested the scrubber inlet pressure (Psi in the roaster) and one of the fan speeds (Nfan1 or N_fan2 in the furnace) as the self-optimizing controlled variables CVs. In this study, we stress and advocate the gSOC-plus-BAB approach as an enhanced design toolkit for the classical and systematical design procedure. The gSOC (global self-optimizing control) is able to efficiently solve measurement combinations as CVs with improved economic performances, while the BAB (branch and bound) algorithm serves to fast screen promising measurement subsets for large-scale problems. Using the enhanced design for the off-gas system, our new findings are to control the combination of roaster's ID fan outlet pressures, 0.494PIDfan1+0.506PIDfan2 (setpoint: −257.04 Pa), and the furnace's fan pressure difference, PIDfan1- PIDfan2 (setpoint: 0). Such simple reconfigurations can dramatically reduce the average economic loss by 53.3% for the roaster and even achieve perfect optimal control for the furnace. Both steady state and dynamic evaluations are carried out to validate the reconfigured control structures.© 2017 Elsevier Inc. All rights reserved.

On the use of the Eleveld PK/PD model for the design of PID control of anesthesia

This paper investigates the use of different pharmacokinetic/parmacodynamic models for the design of a PID-based control structure for total intravenous anesthesia. In particular, a PID controller tuned by exploiting the Schnider model for propofol administration (which has been developed for adults) in order to ensure the required robustness and performance is evaluated by considering patients modelled by using the recently developed Eleveld model. The latter is more general and, in principle, takes into account children, adults and elderly people. Simulation results show that clinically acceptable performance are obtained, disregarding the adopted model, for children and adults. On the contrary, the use of the Eleveld model to tune the controller for elderly people, for which a significant delay emerges, requires further investigation.

Study on Single-Loop FCS-MPC for DC-Based DFIG System

Doubly fed induction generator (DFIG) system suffers from complex control structure, slow dynamic response speed and cumbersome parameter design due to its traditional cascaded dual-loop control strategy. A single-loop finite control set model predictive control (SLMPC) is proposed in the paper for DC-based DFIG in DC grid, which simplifies its control structure and parameter design, and enhances system dynamic response. There are three improved aspects. First, the single-loop control structure is proposed to eliminate intermediate link in dual-loop cascaded structure, and enhance system dynamic response. Second, system reduced-order discretization algorithm is proposed by differential and integral discretization method to reduce finite control set model predictive control strategy (FCS-MPC) design difficulty. Third, cost function with nonlinear additional current limiting function is designed to protect system from overcurrent effectively. Finally, the feasibility of proposed strategy is verified by simulations and experiments.

Structured controller synthesis through block-diagonal factorization and parameter space optimization

Constraints on the feedback structure arise in many control systems due to implementing cost, hardware limitations and operational reliability. The parameter space method aims to solve the robust structured controller design problems based on a convex reformulation technique. Despite its attractiveness, the structural constraints are limited to be either decentralized or linear dependence among entries within the same row or column in the current literature. And the global optimal solution is yet to be guaranteed, since a non-convex constraint is introduced in the parameter space after reformulating it as the output feedback synthesis problem. In this paper, we extend the parameter space method to a more generalized structured optimal control problem, such that the linear dependence can occur among its arbitrary entries. A bilinear factorization to the feedback gain matrix is proposed by a special Kronecker product decomposition. Subsequently, an equivalent transformation is proposed to convert this structured control design problem to a controller synthesis problem under decentralized full-state feedback. Thereby, the prior non-convex constraint in the parameter space is removed and the globally optimal structured controller is synthesized by convex programming. Examples such as integrated design and formation control demonstrate its practical appeals.

A control philosophy for complex Non-square chemical process

All the complex non-square chemical processes may have thousands of measurement and control loops and these loops should be paired properly. A term control philosophy decides the structural decisions of the overall plant instead of the term plantwide control which is not meant for tuning each of these loops. Operational safety require direct inclusion of control system into associated safety to handle disturbances and failure in critical devices of a chemical process. Though most of the process units are non-linear and multivariable in nature, their operations are based on linear controllers to provide overall stability and safe operations. As the design of an appropriate control structure for complex non-square chemical processes are difficult, it is very challenging to control these processes. Non-square systems offers safe operational procedures and ensures plant safety. The proposed method of control configuration selection for non-square Multi Input Multi Output (MIMO) system is an extension of square MIMO system. An appropriate selection of control configuration for non-square chemical processes have been addressed in this paper. The proposed method of dynamic loop interactions is based on the computation and comparison of areas under responses for all possible combinations of manipulated and controlled variables. The control configurations that emerged from subsequent analyses are able to provide adequate inherent safety to the overall process in a closed-loop sense. This paper assesses the interaction among the loops having unequal number of input and output variables. This procedure is illustrated via simulation of examples taken for both the under-defined and over-defined non–square MIMO system. Also the quantitative measure of process safety index is obtained for the process.