Open-loop System Research Articles

Advanced semiconductor materials in power electronic switches for energy-efficient converters in an electric vehicle charging system with closed-loop FOPID control

The growth in consumer use of electric vehicles is influencing the electrification of transportation in greener and more energy-efficient ways. The availability of high-speed charging stations is crucial to the commercial viability of electric vehicles (EVs). This article examines the development, evaluation, and next steps for several Vienna converter topologies for DC fast-charging systems. The designs and evaluations of these converters are provided, reviewed, and contrasted. The work primarily focuses on several Vienna rectifier topologies on DC quick charging stations that result in fewer CO2 emissions in EV charging stations, aiding in climate action and sustainable development goals. Open-loop and closed-loop charging systems are also discussed in this study to provide improved charging efficiency. The closed-loop system is developed with PI and FOPID controllers; the system is simulated in MATLAB Simulink, and the outputs are obtained to produce a system with higher efficacy. The outputs of the two controllers were compared in terms of time domain metrics like rise time, peak time, settling time, and steady-state error. Results are compared, and it is discovered that the closed-loop charging system with the Vienna rectifier and FOPID controller works better in every way. When charging an EV battery, the performance and efficiency of the Vienna converter circuit, a power electronic switching device, depends on its material qualities. Typically, these switches are constructed from silicon. Switching devices use broad-band semiconductors because of developments in material science and a need for higher performance. This work also discusses the semiconductor material used to create the power electronic switches used in the Vienna Converter.

PIDD2 Control of Large Wind Turbines’ Pitch Angle

The pitch control system has a profound impact on the development of wind energy, and yet a delay or non-minimum phase can weaken its performance. Thus, there is a strong incentive to enhance pitch control technology in order to counteract the negative effects of unidentified delays and non-minimum phase characteristics. To reduce the complexity of the parameter-tuning process and improve the performance of the system, in this paper, we propose a novel control method for wind turbine pitch angle with time delays. Specifically, the proposed control method is state-space PIDD2, which is based on internal model control (IMC) and the open-loop system step response. Then, considering the tracking, disturbance rejection and measurement noise, the proposed controller is verified through simulations. The simulation results demonstrate that the state-space PIDD2 (SS-PIDD2) can provide a trade-off between robustness, time domain performance and measurement noise attenuation and effectively improve pitch control performance in contrast to series PID and PI control methods.

Distributed consensus control for voltage tracking and current distribution in DC microgrid

DC microgrids are extensively researched because of advancements in power electronics, penetration of DC loads, and the growing demand for DC power. The DC microgrid is also broached as a multi-agent system (MAS) because of its distributed nature. In this paper, a distributed consensus controller for DC microgrids is proposed that has basically two main objects; the first object is to track the desired reference voltage for the distributed generation units while maintaining the voltage stability at the point of common coupling (PCC), whereas the second object is to distribute current proportionally among distributed loads. Furthermore, a linear distributed model is constructed in which the dynamics of the net current for the distributed generation units are established using the directed graph of power lines. Moreover, local information from neighboring agents is utilized to construct a distributed linear controller, and the consensus control problem is solved for voltage tracking and current distribution of the DC microgrid. Furthermore, the control gains for the proposed controller are optimized using closed-loop stability analysis. Finally, simulation results are illustrated for both open-loop and closed-loop systems, and the effects of the directed power line graph and the undirected communication graph are analyzed. The effects of parameter uncertainties on the performance of the proposed controller are investigated through simulations. The results show that the distributed controller efficiently solves the consensus control problem for the MAS.

Accuracy Improvement of Braking Force via Deceleration Feedback Functions Applied to Braking Systems.

Currently, braking control systems used in regional railways are open-loop systems, such as metro and tramways. Given that the performance of braking can be influenced by issues such as wheel sliding or the properties of the friction components present in brake systems, our study puts forward a novel closed-loop mechanism to autonomously stabilize braking performance. It is able to keep train deceleration close to the target values required by the braking control unit (BCU), especially in terms of the electrical-pneumatic braking transform process. This method fully considers the friction efficiency characteristics of brake pads and encompasses running tests using rolling stock. The test results show that the technique is able to stabilize the actual deceleration at a closer rate to the target deceleration than before and avoid wheel sliding protection (WSP) action, especially during low-speed periods.

Data-driven fault detection for Lipschitz nonlinear systems: From open to closed-loop systems

This paper proposes a novel data-driven fault detection (FD) method for Lipschitz nonlinear systems. The proposed method is developed by considering that the sample size of training data is limited, while the global system nonlinearity is taken into account. It is a nonparametric approach and consists of two FD versions corresponding to open-loop and closed-loop systems, respectively. It achieves a tradeoff between approximation and estimation errors. By quantifying the unknown modeling error that is closely related to the threshold used in FD tasks, an upper bound is obtained so that trial-and-error for finding the threshold can be avoided. The effectiveness of the proposed data-driven schemes is illustrated by two simulation studies.

Antimicrobial Resistance: A Misuse or Overuse of Antibiotics?

The effectiveness of antibiotics in treating infections in patients is declining as antibiotic-resistant bacteria become alarmingly powerful. We might be failing to understand the cliche that the emergence of antibiotic-resistant bacteria is caused by the overuse and abuse of antibiotics. The high cost of pharmaceuticals serves as an example of the failure of the current system. One medicine costs over $5 billion and takes 15 years to create. There is minimal input into the open-loop system that produces new medications. Because pharmaceuticals are not tailored, this ineffective method produces drugs that are dangerous to the majority of the target population and only work for a small portion of that population. This issue can only be resolved by a complete return to nature rather than by just increasing R&D spending.

Modelling and Control of a Two-Wheel Inverted Pendulum Using Fuzzy-PID-Modified State Feedback

Control of mechanical systems by electronic systems controlled by computer programs is one of the most active research areas in mechatronic systems engineering. These programs carry out control laws, which are algorithms. This study focuses on Segway control (a two-wheeled inverted pendulum which is a highly nonlinear and unstable open-loop system). Our research entails creating a control law to stabilize this system. We proposed using a state feedback controller, which provided us with a stable system and a lower error margin; however, to correct this error, we used a combination of the state feedback controller and the fuzzy-PID controller. The effectiveness of the proposed method is demonstrated using simulation results.

Stability Control of Humanoid Biped Robot using PID Controllers

As technology has advanced, the usage of robots has become a major worldwide issue, especially for robots that interact with people. Humanoid biped robots have the potential to function as people's helpers, capable of assisting society and replacing humans in various or dangerous tasks. However, despite advances in robotic stability control, robust control for a broad variety of applications remains a difficulty. The purpose of this research is to look at optimum control techniques for stability control in humanoid biped robots in order to obtain superior stability. To regulate the robot's stability, several control techniques such as Proportional-Integral-Derivative control, Proportional-Integral control, Proportional-Derivative control, and Linear Quadratic Regulator (LQR) are utilised. Before implementing these control techniques, the humanoid biped robot's open loop system is evaluated to determine its stability response. To investigate the system response of robot stability control, the MATLAB programme is used.

A Low-Noise Micromachined Accelerometer with Reconfigurable Electrodes for Resonance Suppression.

We present a high-performance capacitive accelerometer with a sub-µg noise limit and 1.2 kHz bandwidth for particle acceleration detection applications. The low noise of the accelerometer is achieved through a combination of device design optimization and operation under vacuum to reduce the effects of air damping. Operation under vacuum, however, causes amplification of signals around the resonance region, potentially resulting in incapacitating it through saturation of interface electronics or nonlinearities and even damage. The device has thus been designed with two sets of electrodes for high and low electrostatic coupling efficiency. During normal operation, the open-loop device utilizes its high-sensitivity electrodes to provide the best resolution. When a strong signal near resonance is detected, the electrodes with low sensitivity are used for signal monitoring, while the high-sensitivity electrodes are used to apply feedback signals efficiently. A closed-loop electrostatic feedback control architecture is designed to counteract the large displacements of the proof mass near resonance frequency. Therefore, the ability to reconfigure electrodes lets the device be used in high-sensitivity or high-resiliency modes. Several experiments were conducted with DC and AC excitation at different frequencies to verify the effectiveness of the control strategy. The results showed a ten-fold reduction of displacement at resonance in the closed-loop arrangement compared to the open-loop system with a quality factor of 120.

Model Predictive Control for a Voltage Sensorless Grid-Connected Inverter With LCL Filter Using Lumped Disturbance Observer

This paper introduces a disturbance observer-based model predictive control for a voltage sensorless grid-connected inverter (GCI), which minimizes the number of sensor measurements and eliminates the steady-state error by estimating the lumped disturbance in the presence of grid impedance variations. A full-state estimation and lumped disturbance observer are obtained based on the Luenberger observer and gradient steepest descent method, respectively. A cost function, which consists of state error, is used for controller gain design. An optimal full-state observer and controller gains are obtained by solving an optimization problem based on linear matrix inequality. The discrete-time frequency responses analysis of open-loop and closed-loop systems is presented to demonstrate the filter resonance suppression. The robustness of the proposed control against grid impedance variation is analyzed through the pole-zero map approach. Simulations and experiments are conducted for a GCI under the grid impedance variation to demonstrate the theoretical analysis and the efficacy of the proposed control schemes.

Multiobjective Distributed Array Beamforming in the Near Field Using Wireless Syntonization

We demonstrate the efficacy of distributed microwave multiobjective beamforming at ranges near field to the array using an optimization algorithm and wireless frequency alignment (syntonization). While considerable research has recently been devoted to distributed phased array coordination, the ability to steer signals to locations close to the array in open-loop (feedback-free) systems has not been demonstrated. In this work, we apply a traditional far-field beamforming algorithm to a set of distributed antennas that are wirelessly syntonized. We demonstrate multiobjective beamforming at 0.9 GHz using software-defined radios (SDRs) in a distributed array steering either two beams (focii) or one beam and one null. This work demonstrates the feasibility of a critical part of future distributed beamforming systems that, when combined with other coordination technologies, will support coherent beamforming in widely distributed wireless systems.

Enhancing Dynamic Stability Performance of Hybrid AC/DC Power Grids Using a New Robust Controller

This research investigates the dynamic performance of a multi-terminal DC (MTDC) network linked to a wind farm side converter. The suggested approach is based on loop shaping, mutual quality decomposition, and an effective H controller architecture (MQDM). The transfer function was built as the wind power plant shifted from the Master-Slave control approach to the conventional feedback control method. The singular value curves of the original open-loop system and the suggested solution are compared in order to derive the weighting functions of the robust H controller. The control gain is then calculated by utilizing the MQDM approach to get the system's transfer function from the state space. By using the single value order reduction approach and frequency response analysis to generate a robust controller's gain, the suggested methodology was put into practice. The suggested method for controlling the DC grid voltage on the MTDC converter on the wind farm side has now been implemented in the MATLAB environment. Applying various uncertainties to the DC grid, wind turbines, and AC grid using simulation data demonstrates how reliable the suggested approach is.

Accuracy of closed-loop and open-loop propofol delivery systems by bispectral index monitoring in breast surgery patients: a prospective randomized trial

BackgroundThis randomized and controlled prospective study tested the hypothesis that closed-loop Target-Controlled Infusion (TCI) of propofol would be associated with better system performance when compared with open-loop controlled delivery of propofol. MethodsPatients scheduled for elective breast surgery were randomly assigned to two groups: a closed-loop group, in which propofol infusion was performed by a closed-loop TCI system that used the Bispectral Index (BIS) as a feedback parameter to titrate the rate of propofol infusion, and an open-loop group, in which propofol infusion was performed manually and guided by the bispectral index. ResultsA total of 156 patients were recruited for this study (closed-loop group n = 79; open-loop group n = 77). The Global Score (GS) of the closed-loop group was lower than that of the open-loop group (34.3 and 42.2) (p = 0.044). The proportions of time with a BIS value between 40 and 60 were almost identical in the closed-loop group and the open-loop group (68.7 ± 10.6% and 66.7 ± 13.3%) (p = 0.318). The individuals in the closed-loop group consumed more propofol compared with those in the open-loop group (7.20 ± 1.65 mg.kg−1.h−1 vs. 6.03 ± 1.31 mg.kg−1.h−1, p < 0.001). No intraoperative recall, somatic events or adverse events occurred. No significant difference in heart rate was observed between the two groups (p = 0.169). ConclusionThe closed-loop protocol was associated with lower BIS variability and lower out-of-range BIS values, at the cost of a greater consumption of propofol when compared to the open loop group. Register numberChiCTR-INR-17010399.

A Method for Robust Partial Quadratic Eigenvalue Assignment with Repeated Eigenvalues

Abstract A new method is proposed for robust partial quadratic eigenvalue assignment problem (RPQEAP) with repeated prescribed eigenvalues. We first derive a result on the solution of partial quadratic eigenvalue assignment problem, which leads to the partial Schur form of the close-loop system. Then by minimizing the normality departure of the partial Schur form of the close-loop system, we assign the prescribed eigenvalues step by step such that the close-loop system is as robust as possible. Our method allows the prescribed eigenvalues are repeated. Moreover, the proposed method does not use the unchanged eigenpairs of the open-loop system and avoids transforming the second-order control system to the first-order system. Numerical experiments show that the proposed method is efficient for solving the RPQEAP with repeated eigenvalues.

Linear controller design approach for nonlinear systems by integrating gap metric and stability margin

In the past few years and in many applications, linear feedback control has proved to be adequate for the control of various nonlinear systems. Therefore, before attempting the controller design phase, it is natural to ask, “When is a linear controller adequate for a nonlinear system?” This article provides a new nonlinearity analysis method based on the gap metric and the stability margin that is able to quantify the nonlinearity degree of a system once it has an internal model control controller. The internal model control strategy is used since it provides a direct measure of the discrepancy between outputs from the nonlinear system and its internal model when both are subject to the same controller. It is shown that a feedback loop may exhibit much lower nonlinearity than an open-loop nonlinear system by a careful design of a single linear internal model control controller via the gap metric and stability margin, used as model-based analysis tools for linear time-invariant systems. Both simulations and an experimental validation on a semibatch reactor prove the effectiveness of the proposed method.

Mine water as a source of energy: an application in a coalfield in Laciana Valley (León, NW Spain)

Mine water can be a renewable and economical source of geothermal and hydraulic energy. Nine discharges from closed and flooded coal mines in the Laciana Valley (León, NW Spain) have been studied. Various technologies for the energy use of mine water, as well as the influence of factors such as temperature, the need for water treatment, investment, potential customers and expansion capacity, have been evaluated by means of a decision-making tool. It is concluded that the most advantageous option is an open-loop geothermal system using the waters of a mountain mine, the temperature of which exceeds 14 °C and whose distance to customers is less than 2 km. A technical–economic viability study for a district heating network designed to supply heating and hot water to six public buildings in the nearby town of Villablino is presented. The proposed use of mine water might help areas that have been greatly affected socioeconomically by the closure of the mines and has other advantages compared to conventional energy systems, such as the reduction of CO2 emissions.Graphical It showing the advantages of using mine water as an energy source for district heating and a simplified layout.

A length-adjustable vacuum-powered artificial muscle for wearable physiotherapy assistance in infants.

Soft pneumatic artificial muscles are increasingly popular in the field of soft robotics due to their light-weight, complex motions, and safe interfacing with humans. In this paper, we present a Vacuum-Powered Artificial Muscle (VPAM) with an adjustable operating length that offers adaptability throughout its use, particularly in settings with variable workspaces. To achieve the adjustable operating length, we designed the VPAM with a modular structure consisting of cells that can be clipped in a collapsed state and unclipped as desired. We then conducted a case study in infant physical therapy to demonstrate the capabilities of our actuator. We developed a dynamic model of the device and a model-informed open-loop control system, and validated their accuracy in a simulated patient setup. Our results showed that the VPAM maintains its performance as it grows. This is crucial in applications such as infant physical therapy where the device must adapt to the growth of the patient during a 6-month treatment regime without actuator replacement. The ability to adjust the length of the VPAM on demand offers a significant advantage over traditional fixed-length actuators, making it a promising solution for soft robotics. This actuator has potential for various applications that can leverage on demand expansion and shrinking, including exoskeletons, wearable devices, medical robots, and exploration robots.

Transmission line characterization and modeling for electronic circuits and systems design

Channel bandwidth-limited high-speed links or interfaces make circuit solutions not efficient. Both recent and subsequent links (SerDes-Serializer/Deserializer) design demand efficient and effective coupling between future circuit design, communication, and optimization. The challenges vary and new solutions are needed. In this article, an analytical wireline model is presented to predict electronic path loss towards adequate designs of electronic circuits and systems. An open loop system analysis is adapted in this paper. Our model was tested against different channels: a legacy channel with via stub discontinuity and FR4 dielectric, and a more recent microwave-engineered channel without stub and NELCO 6,000 dielectric, a very good matching attained. Good agreement was observed between our model and electromagnetic full-wave simulation data, as a result showed high level of applicability to thin-film microstrip line for adequate circuit design. The model is recommended for electronic engineers for adequate and faster interfaces and high-speed links designs.

Tracking control of a cart-pendulum underactuated system around its vertical up position

This research provides a solution to the challenging problem of enforcing a periodic or cyclic motion in underactuated systems, even when the upper position is an unstable equilibrium point of the open-loop system. Here, we present the solution to the tracking control problem of an underactuated cart-pendulum system, where the pendulum is forced to oscillate around its upward position. A two-relay controller was used to generate a desired trajectory, which is a locally asymptotically stable limit cycle, for the system in question. The tuning of the two-relay controller to produce the desired frequency and amplitude is also discussed. Furthermore, a twisting controller is designed to ensure the robustness properties of the closed-loop system, which is verified from Lyapunov stability analysis. The positions and velocities of the cart and the pendulum were assumed to be available for feedback. Numerical and experimental results validated the theoretical analysis.

FSTSMC Compliance Control for Dual-Arm Space Robot With SDBD Capture Satellite Operation

Abstract A space robot inevitably impacts a satellite in a capture operation. If its fragile joints are not protected, they may be damaged, resulting in failure of the capture operation. Thus, a spring damper buffer device (SDBD) is added between the joint motors and manipulators to absorb the impact energy, and provide a compliance strategy matched with the SDBD for stable control of the hybrid system. The dynamic modes of the dual-arm space robot open-loop system and target satellite system are established by the Lagrange function before capture. From the momentum theorem, velocity constraints, closed-chain geometric constraints, and Newton's third law, the closed-chain dynamic model of the hybrid system after capture is obtained, and the impact effect and impact force are calculated. For stable control of the hybrid system while limiting joint? impact torque within the safe range, an adaptive fractional-order super-twisting sliding mode compliance control strategy matching the SDBD is proposed. It can effectively improve the fast convergence and trajectory tracking performance of the system whose velocity and acceleration cannot be measured. The stability of the hybrid system is demonstrated by the Lyapunov theorem, and the anti-impact performance of the SDBD and the effectiveness of the compliance strategy are demonstrated through numerical simulation.