Loop Control Algorithm Research Articles

A novel approach of fatigue testing and evaluation of electronic systems based on phase tracking

This paper presents an experimental approach to perform fatigue testing of a lightly damped electronic assembly subjected to harmonic excitation. By leveraging the power of the phase locked loop control algorithm, our proposed work aims to accurately track the phase of the system. This innovative approach enables precise measurement of the drop in resonant frequency due to fatigue, enhancing overall damage prediction. The proposed approach exploits the characteristics of the materials that the phase at the resonance is constant and for a lightly damped system, the value is close to pi/2. In the event that the test article experiences fatigue, and the resonant frequency undergoes a change, the controller will promptly adapt to the new frequency while upholding a constant phase, ensuring the uninterrupted continuity of the testing process. The proposed approach is demonstrated by using the Ball Grid Array (BGA) electronic package as an example, where the test setup, data acquisition, and data monitoring for identifying the interconnect failure are presented. Failure analysis of the test article shows that the primary failure mode is the solder joint failure at the Intermetallic (IMC) layer. A finite element model is developed and correlated with experimental modal analysis to accurately estimate maximum stress and deflection in solder joints. By utilizing the obtained results, one can create a more accurate SN curve for the tested material. This will allow for a better understanding of the material's fatigue behavior and enable more precise predictions of its durability in real-world applications.

Sensors Based Optimized Closed Loop Control Algorithm to Minimize Hypoglycemia/Hyperglycemia using 4-Variate Time Series Data

Sensors Based Optimized Closed Loop Control Algorithm to Minimize Hypoglycemia/Hyperglycemia using 4-Variate Time Series Data

A Control Strategy for Combined Series-Parallel Active Filter System under Non-Periodic Conditions

In this study, generalized non-active power theory based control strategy is proposed for a 3-phase 4-wire Combined Series-Parallel Active Filter (CSPAF) system using a Three-Dimensional (3D) Space Vector Pulse Width Modulation (SVPWM). The CSPAF system consists of a Series Active Filter (SAF) and a Parallel Active Filter (PAF) combination connected a common Direct Current (DC) link for simultaneous compensating the source voltage and the load current. The generalized non-active power theory was applied in previous studies for the PAF control, in this study the theory is used for the CSPAF system control under non-sinusoidal and nonperiodic current and voltage conditions. The closed loop control algorithm for the proposed CSPAF system has been described to direct control of filtering performance by measuring source currents and load voltages for the PAF and the SAF, respectively. The proposed control strategy has been verified by simulating the CSPAF system in Matlab/Simulink environment.

A compact fractional-order model for hypnosis in general anesthesia

The research field of clinical practice has witnessed a notable increase in the integration of information technology and control systems engineering tools and the paradigm of drug dosing management for general anesthesia is no exception. Progressing from adequate to optimal drug dosing requires suitable models for closed loop control algorithms. High order, complex parameterized models for hypnosis are available but as one cannot measure real drug concentrations, accurate modelling is not possible. Moreover, ethical limitations impose serious restrictions as to the type of excitatory signals acceptable to patient effect response evaluations. This paper proposes an innovative approach to determine fractional order models to compactly represent the dynamics inherent to the hypnosis response. A simplifying assumption is being made: instead of multi-compartmental models, a single transfer model is proposed consisting of a fractional-order dynamic that directly connects Propofol, the administered drug, and the Bispectral (BIS) index, the measure of hypnosis. The proposed model is validated against clinical data and compared to integer order models to prove its suitability. Results suggest the model may be well used with control algorithms for computerized drug dosing management.

Research on integrated aircraft-engine control method of hypersonic vehicle based on dynamic inversion control

In order to reduce the influence of the coupling characteristics between the aircraft and engine of hypersonic vehicle, an integrated aircraft-engine control method of hypersonic vehicle is studied in this paper. Firstly, the control-oriented aircraft-engine integrated mathematical model of the hypersonic vehicle is established. Then, by using the nonlinear dynamic inversion (NDI) and the incremental nonlinear dynamic inversion (INDI), the outer loop control algorithm with slow attitude change and the inner loop control algorithm with fast angular rate change are respectively designed. Moreover, based on the online ontology model including aircraft-engine coupling characteristics of the hypersonic vehicle, the coupling control scheme of flight posture and engine of the hypersonic vehicle is designed in the form of control linkage. Finally, the reference model, error control, online estimation and other modules are introduced into the NDI controller to ensure the flight quality and robustness requirements of the hypersonic vehicle. The simulation results show that the aircraft-engine coupling control scheme based on the NDI achieves the expected control performance.

Virtual Inertia Control for CHB-STATCOM in a Power Electronics Dominated Grid

Integration of renewable energy sources (RESs) leads the power system to be a low inertia system, resulting in frequency deviation in the grid. This paper presents a cascaded H-bridge (CHB) converter-based static synchronous compensator (STATCOM) providing virtual synchronous inertial support. This topology achieves two functionalities. 1. It reduces the system frequency deviation in a power electronics dominated grid (PEDG) following the updated grid codes. 2. Without disturbing the normal operation of CHB-STATCOM, it provides reactive power support. This topology uses the cumulative stored energy in the distributed DC-bus capacitors of CHB-STATCOM to improve the frequency nadir/zenith and the rate of change of frequency (RoCoF), preventing frequency instability. A closed- loop control algorithm is developed, which injects an adequate amount of stored energy to prevent frequency variation. It also facilitates re-energizing the capacitors in a smooth fashion, so that subsequent frequency events can be taken care of. For this, a high-pass-filter (HPF) is designed for autonomous DC- link voltage restoration for CHB converter. Relationship between frequency variation and inertial energy support by CHB is analyzed in depth. Finally, the viability of the proposed theory is verified in OPAL-RT test bench for step-up and step-down load change.

Experimental Studies on the Vibration Control of Epoxy Clay Nanocomposites

Fabrication of nanocomposites for different-clay (alumino-silicate) concentrations (1, 3, 5 and 10 wt%) with the matrix (epoxy) is done by using shear mixer. This paper presents the experimental study of free vibration and damping characteristics. The work also involves vibration control of nanocomposite laminates by reinforcing organically modified montmorillonite clay in the epoxy matrix by resin casting technique. Theoretical study is also carried out to study the vibration and damping characteristics of epoxy clay nanocomposites. Dynamic result shows that the second phase nanoscale dispersion in the matrix significantly enhances the internal damping of nanocomposites. This work also presents the active vibration control of nanocomposite beams. Piezoelectric patches are bonded on the surface of beam and control algorithms are applied to the system. Feed forward (open loop) control algorithms are used to control the vibration. Maximum control is obtained for sample with 3 wt.%OC.

Numerical investigation on thermal performance of thermoelectric-cooler integrated cold plate of thermal control liquid loop in spacecraft

The traditional single-phase fluid loop (SFL) and traditioanl thermal control algorithm can barely control the temperature rapidly. Thermoelectric cooler (TEC) has been proved to be a good thermal controller because of its high reliability, liquid-free characteristics, and fast response. This paper proposes a TEC-based precooling module that resides in front of the cold plate (CP), and consists of a TEC-CP system, manifesting a high compatibility between the novel precooling module and traditional SFL. The TEC-CP system was designed, and a mathematical model of heat and mass transfer was developed to numerically investigate the effects of the geometric parameters, TEC operating conditions, and liquid cooling states of the precooling module upon payload thermal performance. Through analysis, an optimal TEC-based precooling module with optimal geometric dimensions was attained, where the coolant temperature was decreased by 13.04 K, resulting in a 28.98% reduction compared to that without the precooling module. Transient results also demonstrate that the temperature response time can be within 3 min, indicating a fast response system for temperature control. Results outlined in this paper provide structural and data references for future designs of scientific rack-level thermal control loops in space stations.

Modal engineering of electromagnetic circuits to achieve rapid settling times.

Inductive circuits and devices are ubiquitous and important design elements in many applications, such as magnetic drives, galvanometers, magnetic scanners, applying direct current (DC) magnetic fields to systems, radio frequency coils in nuclear magnetic resonance (NMR) systems, and a vast array of other applications. They are widely used to generate both DC and alternating current (AC) magnetic fields. Many of these applications require a rapid step and settling time, turning the DC or AC magnetic field on and off quickly. The inductive response normally makes this a challenging thing to do. In this article, we discuss open loop control algorithms for achieving rapid step and settling times in four general categories of applications: DC and AC systems where the system is either under- or over-damped. Each of these four categories requires a different algorithm, which we describe here. We show the operation of these drive methods using Simulink and Simscape modeling tools, analytical solutions to the underlying differential equations, and experimental results using an inductive magnetic coil and a Hall sensor. Finally, we demonstrate the application of these techniques to significantly reduce ringing in a standard NMR circuit. We intend this article to be practical, with useful, easy-to-apply algorithms and helpful tuning tricks.

Evaluation of control strategies applied in small-scale photovoltaic solar tracking systems: a review

This work evaluates the control algorithms applied to decentralized photovoltaic solar tracking systems. For this, the control strategies are divided into three: open loop, closed loop and hybrid loop. Each strategy is screened for its suitability as a suitable technology for small-scale applications, defined by meeting a set of eleven attributes. A specialized literature review process was developed specifically to present the potential of each control algorithm strategy, through an evaluation matrix. The analysis of the algorithms and attributes was carried out using the formal methodology of concept analysis. To facilitate the processing of the information, free access software called “concept Explorer” is used. The analysis carried out shows that open loop control algorithms currently have a greater application in one and two-axis solar tracking systems. Additionally, the on-off control is the one with the greatest application for the three types of control loops evaluated. Finally, the applied methodology has proven to be useful for the evaluation of information and serves as a reference, to carry out analyzes that group and link different alternatives as a model for evaluating a deterministic set of attributes.

Multi‐functional control strategy for power quality improvement of three‐phase grid using solar PV fed unified power quality conditioner

This article presents a generalised integrator with a band-pass filter frequency locked loop (GI-BPF-FLL) control algorithm for the solar photovoltaic (SPV)-integrated unified power quality conditioner (SPVUPQC) system. This control algorithm extracts fundamental components (FC) of the distorted and deformed input signals, and it has the competence of eliminating DC-offset. The key objective is to decrease the number of sensors used in the control algorithm of the SPVUPQC system while enabling the power quality enhancement features in the distribution grid. The effectiveness of the presented GI-BPF-FLL control algorithm and its performance comparison with the conventional control algorithm are discussed in both the time domain as well as frequency domain analysis. The SPVUPQC system consisting of a distribution static compensator (DSTATCOM) and a dynamic voltage restorer (DVR), to compensate simultaneously both the voltage distortions, sag/swell etc. as well as current harmonics, reactive power and load currents unbalances etc. The model of the SPVUPQC system is developed in the MATLAB/Simulink environment, and its results are presented to demonstrate its capabilities. The system's validation is also done on the hardware prototype, and it performs effectively for the voltage and current power quality enhancement simultaneously. The load side voltages magnitudes, grid side voltages and the grid currents total harmonic distortions are found within the boundaries specified in the IEEE standard 1159 and the IEEE standard 519.

An In Silico Head-to-Head Comparison of the Do-It-Yourself Artificial Pancreas Loop and Bio-Inspired Artificial Pancreas Control Algorithms.

User-developed automated insulin delivery systems, also referred to as do-it-yourself artificial pancreas systems (DIY APS), are in use by people living with type 1 diabetes. In this work, we evaluate, in silico, the DIY APS Loop control algorithm and compare it head-to-head with the bio-inspired artificial pancreas (BiAP) controller for which clinical data are available. The Python version of the Loop control algorithm called PyLoopKit was employed for evaluation purposes. A Python-MATLAB interface was created to integrate PyLoopKit with the UVa-Padova simulator. Two configurations of BiAP (non-adaptive and adaptive) were evaluated. In addition, the Tandem Basal-IQ predictive low-glucose suspend was used as a baseline algorithm. Two scenarios with different levels of variability were used to challenge the algorithms on the adult (n = 10) and adolescent (n = 10) virtual cohorts of the simulator. Both BiAP and Loop improve, or maintain, glycemic control when compared with Basal-IQ. Under the scenario with lower variability, BiAP and Loop perform relatively similarly. However, BiAP, and in particular its adaptive configuration, outperformed Loop in the scenario with higher variability by increasing the percentage time in glucose target range 70-180 mg/dL (BiAP-Adaptive vs Loop vs Basal-IQ) (adults: 89.9% ± 3.2%* vs 79.5% ± 5.3%* vs 67.9% ± 8.3%; adolescents: 74.6 ± 9.5%* vs 53.0% ± 7.7% vs 55.4% ± 12.0%, where * indicates the significance of P < .05 calculated in sequential order) while maintaining the percentage time below range (adults: 0.89% ± 0.37% vs 1.72% ± 1.26% vs 3.41 ± 1.92%; adolescents: 2.87% ± 2.77% vs 4.90% ± 1.92% vs 4.17% ± 2.74%). Both Loop and BiAP algorithms are safe and improve glycemic control when compared, in silico, with Basal-IQ. However, BiAP appears significantly more robust to real-world challenges by outperforming Loop and Basal-IQ in the more challenging scenario.

Fuzzy logic aided PPF controller design to active vibration control of a flexible beam

This paper presents a fuzzy-logic-based observer and a positive position feedback controller to reduce a standard beam's free vibrations using a piezoelectric actuator. It is aimed that fuzzy-logic-based observer is used as feed-through and improves the overall performance of the PPF controller. For this aim, the cantilever beam and a piezoelectric patch are initially numerically modeled using the finite element method considering the close loop control algorithm. The displacement and strain responses results are compared with the experimental model. Then, two controllers are applied to the designed system: positive position feedback (PPF) and fuzzy-logic-based positive position feedback (FLBPPF). The uncontrolled and controlled system responses are investigated and compared in terms of the linear strain and tip displacement results. Using the FLBPPF controller, the settling times of controlled systems are decreased by about 20.7% and 41.6% regarding the linear strain and tip displacement response compared to the PPF controller.

Data-Driven Virtual Replication of Thermostatically Controlled Domestic Heating Systems

Thermostatic load control systems are widespread in many countries. Since they provide heat for domestic hot water and space heating on a massive scale in the residential sector, the assessment of their energy performance and the effect of different control strategies requires simplified modeling techniques demanding a small number of inputs and low computational resources. Data-driven techniques are envisaged as one of the best options to meet these constraints. This paper presents a novel methodology consisting of the combination of an optimization algorithm, two auto-regressive models and a control loop algorithm able to virtually replicate the control of thermostatically driven systems. This combined strategy includes all the thermostatically controlled modes governed by the set point temperature and enables automatic assessment of the energy consumption impact of multiple scenarios. The required inputs are limited to available historical readings from smart thermostats and external climate data sources. The methodology has been trained and validated with data sets coming from a selection of 11 smart thermostats, connected to gas boilers, placed in several households located in north-eastern Spain. Important conclusions of the research are that these techniques can estimate the temperature decay of households when the space heating is off as well as the energy consumption needed to reach the comfort conditions. The results of the research also show that estimated median energy savings of 18.1% and 36.5% can be achieved if the usual set point temperature schedule is lowered by 1 °C and 2 °C, respectively.

Feedforward Control Algorithms for MEMS Galvos and Scanners

Optical systems typically use galvanometers (galvos) and scanners. Galvos move, quasi-statically, from one static position to another. Scanners move in an oscillatory fashion, typically at the device resonant frequency. MEMS devices, which have many advantages and are often used in optical systems, are typically high Q devices. Moving from one position to another for a galvo or one amplitude to another for scanners, can take many periods to settle following the ring down. During these transitions, the optical system is inactive. Here, we show how precisely timed pulses can be used (in an open loop manner) to begin or end scanner motion without ring up/ring down time. The size of pulse required is found to depend on the Q of the device, and relationships are derived. The pulse can also be separated into multiple pulse spaced one period apart if pulses of the necessary size are not possible due to constraints of the physical device. For finite Q scanners, the amplitude decreases after the initial pulse due to damping. This can be eliminated by applying an excitation at the frequency of the scanner. The necessary amplitude for this excitation is derived. Finally, by combining this open loop control algorithm with an open loop control algorithm for galvo motion the device can seamlessly move between scanner and galvo functioning. These control algorithms are demonstrated using computer simulations, analytical models and a commercially available MEMS mirror (Mirrorcle Technologies, A8L2.2).

A double closed loop control algorithm based on current mode in full bridge circuit

In order to improve the problems of large output current and voltage ripples and slow system response when the full-bridge circuit is working. This paper proposes a double closed-loop control algorithm based on current mode. Use fuzzy controller to optimize the parameters of voltage outer loop PID controller. The genetic controller is used to optimize the parameters of the current inner loop PID controller. After the dual closed-loop structure of the current control mode is optimized for the traditional PID controller, the overshoot is reduced, the system response speed is accelerated and the current ripple and voltage ripple are also greatly reduced. The simulation verifies the effectiveness of the designed double closed-loop control algorithm.

Controller Development for Magneto-Rheological Semi-Active Suspension System to Improve Vehicle Safety

&#x0D; &#x0D; &#x0D; Vehicle suspension system would complement vehicle safety in terms of ride comfort, handling and braking, and also isolation from road irregularities. This can be better achieved by introducing a semi-active suspension system where the magneto-rheological (MR) fluid is used to manipulate its damping characteristics. This paper explains the controller development for MR semi-active suspension system. The process started by developing the non-parametric linearized data driven (NPLDD) double input with proportional-integral (PI) controller as an inner loop algorithm for MR damper modelling and force tracking control; then, Improved PI controller as an outer loop control algorithm for vehicle response improvement, and finally validation work using quarter-car test bench. All the algorithm development is based on Perusahaan Otomobil Nasional (PROTON) vehicle characteristics and specifications. From the simulation results, it is verified that the NPLDD double input model together with the PI control strategy has the capability to track the desired damping force well. Meanwhile, the Improved PI controller for the outer loop is capable to reduce the magnitude of vehicle body acceleration and displacement. The validation at the quarter-car test bench also shows significant reduction of these two parameters. As a result, the PI controller for the MR semi-active suspension system is found sufficient for vehicle safety improvement.&#x0D; &#x0D; &#x0D;

The System Design of an Autonomous Mobile Welding Robot

The welding robot system designed in this paper is helpful to realize welding automation. The closed loop control system and algorithm of arc rotating speed have been designed, so arc rotating speed was stabilized near the set value and the tracking accuracy of fillet weld has been improved by the rotating arc sensor. A data acquisition system and a motion control system have been designed based on multi-sensor technology. The mapping relationship between the features in the welding seam image and the pose of the welding gun was established, so as to realize the identification of the pose of the welding gun based on three-wire laser vision sensing technology. The effect of wire extension, welding currents and welding voltages on the current waveform was investigated based on the rotating arc sensor. By using the designed system and algorithm, the welding deviations recognition experiment, the arc rotating speed control experiment and the tracking experiment of the right-angle welding seam have been carried out. The experimental results showed that the welding deviations were located within [Formula: see text][Formula: see text]mm, and the welding robot can track the complex welding seam accurately and reliably.

A fuzzy rule based control algorithm for MPPT to drive the brushless dc motor based water pump

In this paper, a solar photovoltaic model integrated with brushless DC motor via DC to DC zeta converter is controlled in two stage. In first stage, a fuzzy rule based maximum power point tracking (PPT) is proposed to generate the pulse for DC to DC zeta converter. It is efficient intelligent control approach to extract maximum power from the solar PV system and enhance the speed to track the maximum power. The basic three process of fuzzy logic controller (FLC) are fuzzifier, inference and defuzzifier where the defuzzification process is used center of gravity (COG) method to convert its original value. The FLC to extract maximum PPT for solar PV based brushless DC motor can be examined the performance under transient and dynamic condition with different solar insolation. Moreover, in second stage a trapezoidal control approach based electronic commutation is chosen to generate the pulses of voltage source inverter (VSI) and it offers the smooth control of the brushless DC motor which can easily applicable for water pumping or irrigation purpose. A second stage, trapezoidal control approach is close loop control algorithm using sensorless drive. The performance of proposed fuzzy rule based control algorithm is shown using simulation results on MATLAB platform.

Robust MMSOGI‐FLL control algorithm for power quality improvement of solar PV‐SyRG pico hydro‐BES based islanded microgrid with dynamic load

The islanded microgrids are vulnerable to stability problems during high penetration of dynamic loads like induction motors (IMs), which results in continuous oscillations in voltage and frequency, resulting in disturbances in the islanded microgrid. In this work, a modified multi-second-order generalised frequency locked loop (MMSOGI-FLL) control algorithm is implemented. This control provides a fast response of the power converter; thereby the microgrid voltage/frequency are stabilised rapidly. Besides, the control also provides the dynamic reactive power for the sudden start of an IM load and regulates the common coupling point voltage in the islanded system. The MMSOGI-FLL control also provides harmonics elimination, fast convergence, DC offset removal and reactive power compensation in the islanded system. The implemented islanded system is a combination of a pico-hydro-based synchronous reluctance generator (SyRG), solar photovoltaic (PV) array and a battery energy storage (BES). The BES is connected at DC link to maintain the power equilibrium under a change in the load and power generation. Moreover, the system used in this work is proficient in feeding the non-linear load and dynamic load of an IM. The performance of this standalone microgrid is validated with extensive tests on the developed prototype, which meets the power quality requirement of the 1547.4 standards.