Intensive Control Research Articles

Homeotic compartment curvature and tension control spatiotemporal folding dynamics

Shape is a conspicuous and fundamental property of biological systems entailing the function of organs and tissues. While much emphasis has been put on how tissue tension and mechanical properties drive shape changes, whether and how a given tissue geometry influences subsequent morphogenesis remains poorly characterized. Here, we explored how curvature, a key descriptor of tissue geometry, impinges on the dynamics of epithelial tissue invagination. We found that the morphogenesis of the fold separating the adult Drosophila head and thorax segments is driven by the invagination of the Deformed (Dfd) homeotic compartment. Dfd controls invagination by modulating actomyosin organization and in-plane epithelial tension via the Tollo and Dystroglycan receptors. By experimentally introducing curvature heterogeneity within the homeotic compartment, we established that a curved tissue geometry converts the Dfd-dependent in-plane tension into an inward force driving folding. Accordingly, the interplay between in-plane tension and tissue curvature quantitatively explains the spatiotemporal folding dynamics. Collectively, our work highlights how genetic patterning and tissue geometry provide a simple design principle driving folding morphogenesis during development.

Dynamic analysis and vibration control for overhead hoist transport

The OHT system is a transport device used for intra- or inter-plant transport in a fab or other factory, the load-bearing part of the goods stored under the trolley generates longitudinal vibration and lateral oscillation due to inertia force When the OHT in the air starts or stops. Firstly, the trolley dynamic model under the action of lateral thrust and longitudinal tensile force need to be established. secondly, the coupling analysis of horizontal oscillation and longitudinal oscillation on the model is carried out. Thirdly, aiming at the lateral swing and longitudinal vibration of the carriage, a double closed-loop vibration control strategy with tension control as inner loop and speed control as outer loop and carry out the simulation analysis of longitudinal vibration control is proposed. In the experiment of the ground trolley, the control strategy is applied. The simulation and experimental results show that the control method can quickly restrain the longitudinal vibration of the trolley bearing plate, reduce the pulling force of the trolley on the lifting steel belt, and avoid the large displacement of the bearing plate in the air.

Kontrola niestabilności kapilarnej w warunkach hydrodynamicznego oddziaływania na złoże

The paper presents the results of studies on optimisation of water impact on a reservoir by means of sequential periodic increase in hydrodynamic pressure in order to extract capillary trapped oil. The method provides a coordinated account of both displacement conditions and capacitive-filtration characteristics of fluid-saturated reservoirs. The results of experimental, theoretical and field studies of mass transfer processes in the presence of hydrodynamic nonequilibrium in heterogeneous porous media are presented. This paper considers a case where capillary forces are the determining factor for the displacement of immiscible liquids. Laboratory test results have shown that the formation of CO2 in the reaction of an alkaline solution with naphthenic components can make an additional contribution to the control of surface tension in porous media. A series of experimental studies were carried out on a core sample model to simulate the oil displacement by in-situ generated CO2 gas-liquid system. The article offers an analytical and technological solution to the problem of ensuring the value of “capillary number” and capillary penetration corresponding to the most complete extraction of trapped oil by regulating the “rate” of filtration (hydrodynamic injection pressure). The paper presents the field cases of implementing the new reservoir stimulation techniques to increase sweep efficiency. For effective residual oil recovery in fluid flow direction, conditions of stepwise (staged) maintenance of specified hydrodynamic water pressure at the boundary of injection contour are considered. Estimated calculations allow to determine time duration and stage-by-stage control of injection pressure as a requirement for reaching the expected increase in oil recovery.

Invasive Mechanical Ventilation in Traumatic Brain Injured Patients with Acute Respiratory Failure.

Patients with severe traumatic brain injury (TBI) need to be admitted to intensive care (ICU) because they require invasive mechanical ventilation (IMV) due to reduced consciousness resulting in loss of protective airway reflexes, reduced ability to cough and altered breathing control. In addition, these patients can be complicated by pneumonia and acute distress syndrome (ARDS). IMV allows these patients to be sedated, decreasing intracranial pressure and ensuring an adequate oxygen delivery and tight control of arterial carbon dioxide tension. However, IMV can also cause dangerous effects on the brain due to its interaction with intrathoracic and intracranial compartments. Moreover, when TBI is complicated by ARDS, the setting of mechanical ventilation can be very difficult as ventilator goals are often different and in conflict with each other. Consequently, close brain and respiratory monitoring is essential to reduce morbidity and mortality in mechanically ventilated patients with severe TBI and ARDS. Recently, recommendations for the setting of mechanical ventilation in patients with acute brain injury (ABI) were issued by the European Society of Intensive Care Medicine (ESICM). However, there is insufficient evidence regarding ventilation strategies for patients with ARDS associated with ABI. The purpose of this paper is to analyze in detail respiratory strategies and targets in patients with TBI associated with ARDS.

Observed-based Event-triggered Sliding Mode Control of Networked Control System for Carbon Fiber Diagonal Loom

In this paper, an observed-based sliding mode control with event-triggered mechanism for the carbon fiber diagonal loom tension networked control is studied. According to the characteristics of the loom, the networked control is introduced into the loom tension control, the influence of the introduction of network factors is fully considered, and a tension model containing network factors is finally established. An observed-based sliding mode control is adopted. Meanwhile, to further reduce the amount of data transmission and improve the service life of the equipment, an event-triggered condition is also introduced, then the asymptotically stability of the proposed control system and the feasibility of control performance are proved through the Lyapunov functional. Finally, the rapid feasibility of the proposed algorithm is demonstrated by a simulation example.

Integrated sliding mode intelligent fractional-order backstepping control of warp tension based on fixed-time extended state observer

The purpose of this study is to develop an integral sliding mode intelligent fractional-order backstepping controller based on a fixed-time extended state observer (ISMIFOBC-ESO) to control warp tension. First, the time-varying mathematical model of the let-off system was studied and converted into the state equation. Due to the parameter uncertainty and healed motion of the let-off system, the total external disturbance of the system is unknown. We designed a fixed-time extended state observer to deal with this situation, the estimated total interference is updated into the control algorithm in real time to reduce the tracking error. The nonlinear integral sliding surface is designed and integrated into the backstepping control to ensure the finite time convergence and stability of the algorithm. The fractional-order theory with more degrees of freedom is introduced further to enhance the control accuracy and robustness of the algorithm, the stability is proved by the Lyapunov theorem and the control law is designed. The simulation experiment verifies the effectiveness of the designed scheme compared with the other two controllers in the case of sinusoidal-like signals and step signals.

Making Nature Personal: Fostering Vulnerability, Compassion, and Personal Growth Through a Transpersonal Eco-Art Process

As the Earth suffers from climate change, global warming, and its inhabitants’ irresponsibility, environmental activists suggest that Earth’s inhabitants must participate in social action to find greater consciousness and compassion for self and others in their relationships with the Earth. The authors engaged in five weekly sessions to use nature-assisted eco-art therapy to explore their individual processes. The themes that emerged included tension–control, submission–dominance, intimacy tolerance, compassion-observing emotions, and separation–retreat. These themes reflect what often develops in both the therapist–individual relationship and within the Earth’s inhabitants as self-regulating organisms.

Liquid Metal-Based Electronics for On-Skin Healthcare.

Wearable devices are receiving growing interest in modern technologies for realizing multiple on-skin purposes, including flexible display, flexible e-textiles, and, most importantly, flexible epidermal healthcare. A 'BEER' requirement, i.e., biocompatibility, electrical elasticity, and robustness, is first proposed here for all the on-skin healthcare electronics for epidermal applications. This requirement would guide the designing of the next-generation on-skin healthcare electronics. For conventional stretchable electronics, the rigid conductive materials, e.g., gold nanoparticles and silver nanofibers, would suffer from an easy-to-fail interface with elastic substrates due to a Young's modulus mismatch. Liquid metal (LM) with high conductivity and stretchability has emerged as a promising solution for robust stretchable epidermal electronics. In addition, the fundamental physical, chemical, and biocompatible properties of LM are illustrated. Furthermore, the fabrication strategies of LM are outlined for pure LM, LM composites, and LM circuits based on the surface tension control. Five dominant epidermal healthcare applications of LM are illustrated, including electrodes, interconnectors, mechanical sensors, thermal management, and biomedical and sustainable applications. Finally, the key challenges and perspectives of LM are identified for the future research vision.

An ADRC Parameters Self-Tuning Control Strategy of Tension System Based on RBF Neural Network

High precision control of substrate tension is the premise and guarantee for producing high-quality products in roll-to-roll precision coating machine. However, the complex relationships in tension system make the problems of decoupling control difficult to be solved, which has limited the improvement of tension control accuracy for the coating machine. Therefore, an ADRC parameters self-tuning decoupling strategy based on RBF neural network is proposed to improve the control accuracy of tension system in this paper. Firstly, a global coupling nonlinear model of the tension system is established according to the composition of the coating machine, and the global coupling model is linearized based on the first-order Taylor formula. Secondly, according to the linear model of the tension system, a parameters self-tuning decoupling algorithm of the tension system is proposed by integrating feedforward control, ADRC and RBF. Finally, the simulation results show that the proposed tension control strategy has good decoupling control performance and effectively improves the tension control accuracy for the coating machine.

A microphysiological system for studying human bone biology under simultaneous control of oxygen tension and mechanical loading.

Throughout life, continuous remodelling is part of human bone biology and depends on the simultaneous action of physicochemical parameters such as oxygen tension and varying mechanical load. Thus, suitable model systems are needed, which allow concomitant modulation of these factors to recapitulate in vivo bone formation. Here, we report on the development of a first microphysiological system (MPS) that enables perfusion, environment-independent regulation of the oxygen tension as well as precise quantification and control of mechanical load. To demonstrate the use of the MPS for future studies on the (patho-)biology of bone, we built a simplified 3D model for early de novo bone formation. Primary human osteoblasts (OBs), which are the key players during this process, were seeded onto type I collagen scaffolds and cultured in the MPS. We could not only monitor cell viability and metabolism of OBs under varied physicochemical conditions, but also visualise the mineralisation of the extracellular matrix. In summary, we present a MPS that uniquely combines the independent control of physicochemical parameters and allows investigation of their influence on bone biology. We consider our MPS highly valuable to gain deeper insights into (patho-)physiological processes of bone formation in the future.

The Effects of Classical Chinese Dance Movements on Personal Awareness and Emotion Regulation

This research aims to explore the effectiveness of a Chinese classical dance therapy group on college students’ self-awareness and emotion regulation. A pretest and quasi-experimental design was used for this study, with 172 college students in China as the research object. The experimental group underwent Chinese classical dance therapy twice every week, three hours every time, until eighteen hours later; meanwhile, the control group did not handle or train. Members of the two groups were tested before and after the "Introspection Scale", "Body Awareness Scale" and "Emotional Regulation Scale", and statistical tests were performed by single-factor covariate analysis (ANOVA) to evaluate the effectiveness of experimental processing. The study found the following: 1. College students participating in the study of Chinese classical dance therapy groups are generally satisfied with or agree with the content of the Chinese classical dance therapy group scheme designed in this study. 2. The Chinese classical dance therapy group can enhance the daily life awareness of college students. 3. The Chinese classical dance therapy group can improve the overall physical awareness, physical use, muscle tension, and physical control of university students. 4. The Chinese classical dance therapy group can increase the awareness of college students that breathing can help relax the body. 5. The Chinese classical dance therapy group can improve the overall emotional regulation and emotional reflection of college students. 6. The Chinese classical dance therapy group can improve college students' emotion adjustment strategies and has a tracking effect on emotional awareness and emotional efficacy. The research results can provide references and suggestions for psychological counseling practitioners and future research.

Analysis and Discussion on Tension of Long Transport Belt

The technical field of belt tensioning force studied in this paper, in particular, relates to a hydraulic belt tensioning device, including a base, a hydraulic system and a rail fixed on the base, and a tail wheel trolley sliding on the rail; This device can provide a large tension to the tail wheel of the conveyor belt to meet the tension required by the long conveyor belt. At the same time, it can automatically adjust the tension to the tail wheel of the conveyor belt according to the tension of the conveyor belt to realize the dynamic tension control of the conveyor belt; The device prevents belt deviation and material leakage, reduces labor intensity of workers, avoids equipment accidents, and improves industrial production capacity.

Experimental determination of the tightening coefficient of bolts according to the din standard

The use of slip-critical connections is very common in the design of critical steel structures and is seen as an effective way to transfer the force in conditions of dynamic loading. The limit state of the connection occurs when the calculated shear stress is reached, which depends on the friction coefficient of the contact planes and the value of the clamping force, equal to the bolt tension stress. In order to ensure the necessary bolt tensioning force, it is necessary to know the bolt tightening coefficient, because according to the current understanding of the slip-critical connection performance, the designed functioning of the bolt connection is ensured when the bolt tensioning force arising at the necessary torque value is achieved. Otherwise, the actual work of the connection will be different from the calculated, because only a given tension force provides the estimated bearing capacity of the bolted connection with friction planes. This article focuses on tensile testing of a bolt and determining the tightening factor of a bolt made of high-strength10.9 M14 steel. The tightening factor is determined with strain gauges by measuring the relative strain of the bolt when the nut is tightened. This method requires specialized equipment and a test bench and can be used in the study of bolt performance in the absence of a certificate or the need to verify or clarify the available data. The results show that the proposed method can provide a stable determination of the coefficient value. The examined bolts were made according to the German standard DIN931, strength 10.9 size M14x220, nuts according to the German standard DIN934, strength 10 size M14. An Instron 1000HDX tensile testing machine was used to plot the performance of the bolt steel. Nut tension control was determined with the use of NOGRAU NTW24-034R torque wrench, and bolt elongation control with FLA 5-11 strain gauges and National Instruments data acquisition system. On the basis of the conducted research, a method for determining the tightening factor of high-strength bolts has been tested and proposed. The proposed method of determining the tightening factor of a high-strength bolt can be used in research work and allows to determine the coefficient in the absence of an appropriate certificate or the need to clarify (verify) the stated value of the coefficient.

Study on Anchoring Effect of Different CFRP Anchors

Prestressed carbon fiber plate (CFRP) is widely used in the field of bridge reinforcement, but the anchoring ways of CFRP are various, and the anchoring performance of different anchoring forms is also different. In this paper, the anchorage performance, failure form and tension control stress of several common anchorage are studied by experiments, the results show that the anchorage effect is the best when the end of the anchor bearing only tension and no other stresses, which can provide some construction guidance for the selection of anchorage in the future.

Minimization of dynamic changes in the tension of long products behind the outlet cage in rolling stock production in coils

Purpose. Justification of technical solutions as to the reduction of the amplitude and reduction of the dynamic change duration in the tension of the rolling stock at the exit of the output cage when moving to winding a new layer to an acceptable level in terms of its effect on the resulting profile of the rolled product through the control of the rotation frequency of an output cage. Methodology. The conducted research was based on a complex model of the process of rolled steel winding with a Garrett-type winder and the tension of rolled steel in the area of the exit cage-winder. To control the actual amount of tension at the output cage exit, it is suggested to use the amount of free deflection of the rolled steel directly behind the cage. The research was carried out by simulating the process of rolled steel winding according to the basic control scheme and control schemes that predict the influence on both drives, i.e. the winder drive and the output cage drive according to the actual value of tension, in various combinations with further analysis and comparison of the obtained results. Findings. It was established that the correction for the deviation of the actual rolling tension in the finishing cage-winder area from the specified value of the winding current of the winder electric drive does not eliminate rolling tension when switching to the next layer winding and the oscillating form of the transition process, which are characteristic of the basic rolling winding scheme. In turn, the correction of the rotation frequency of the output cage rolls drive reduces the amplitude of the roll tension jerk by almost half with a simultaneous reduction in the time of the transition process and readjustment when switching to a new layer winding. Originality. It has been shown for the first time that the introduction of the roll tension control circuit by correcting the high-speed rolling mode of the output cage ensures minimization of dynamic changes in the rolled steel tension when switching to a new layer winding and reduces the probability of local tightening of rolled steel profile. Practical value. The use of the described technical solutions in the control system of the section of rolled products winding of the small-grade wire mill DSDS 250/150-6 PJSC ArcelorMittal Kryvyi Rih ensures the improvement of the commercial properties of the winding of rolled products produced on the rolling mill.

Constant Tension Control System of High-Voltage Coil Winding Machine Based on Smith Predictor-Optimized Active Disturbance Rejection Control Algorithm.

In the production process of high-voltage coils, a constant tension control system is designed to improve the quality of the transformer. The system is composed of a controller, execution structure, detection structure, etc. The active disturbance rejection control (ADRC), optimized by the Smith predictor (SP), is adopted to achieve constant tension control. The experiment results show that the tension control system based on the SP-ADRC has higher control accuracy, shorter stabilization time and stronger anti-interference ability compared with the traditional PID algorithm. The actual experiment shows that the constant tension control system of the high-voltage coil winding machine based on SP-ADRC has a superior control effect and high practical value.

Carbon Fibers from Wet-Spun Cellulose-Lignin Precursors Using the Cold Alkali Process

In recent years, there has been extensive research into the development of cheaper and more sustainable carbon fiber (CF) precursors, and air-gap-spun cellulose-lignin precursors have gained considerable attention where ionic liquids have been used for the co-dissolution of cellulose and lignin. However, ionic liquids are expensive and difficult to recycle. In the present work, an aqueous solvent system, cold alkali, was used to prepare cellulose-lignin CF precursors by wet spinning solutions containing co-dissolved dissolving-grade kraft pulp and softwood kraft lignin. Precursors containing up to 30 wt% lignin were successfully spun using two different coagulation bath compositions, where one of them introduced a flame retardant into the precursor to increase the CF conversion yield. The precursors were converted to CFs via batchwise and continuous conversion. The precursor and conversion conditions had a significant effect on the conversion yield (12–44 wt%), the Young’s modulus (33–77 GPa), and the tensile strength (0.48–1.17 GPa), while the precursor morphology was preserved. Structural characterization of the precursors and CFs showed that a more oriented and crystalline precursor gave a more ordered CF structure with higher tensile properties. The continuous conversion trials highlighted the importance of tension control to increase the mechanical properties of the CFs.

Underactuated control and analysis of single blade installation using a jackup installation vessel and active tugger line force control

The assembly and installation costs account for a large share in the overall expenditures of an offshore wind farm project. Single blade installation is suitable for large scale wind turbines due to the lower crane capability requirement and lower transportation time. By introducing active tension control on the tugger lines, an automatic single blade installation approach can accomplish operations in higher sea states, reduce the waiting-on-weather time, and improve the operational efficiency. Compared to early research, a more complicated control objective is achieved in this paper, i.e., a two-tugger-line configuration is applied to stabilize the suspended blade in three degrees of freedom during crane rotation and blade root-hub mating processes. The pulleys on the crane boom, i.e., the ends of the tugger lines, are assumed to be fixedly placed, resulting in tugger line time-varying inclinations. A novel backstepping-like controller is designed and proved. It is able to stabilize the blade around its equilibrium and make it track the desired path. Sensitivity studies are conducted to evaluate the influence of the tugger line inclinations. In addition, the influence of the installed blades on a three-blade horizontal wind turbine with a monopile foundation is discussed. The proposed active control setup improves the installation success rate and reduces the risks for blade impacts that may occur during mating.

Stress distribution of the nonwoven fabric package during winding

During winding, the defects of wrinkles and buckling are prone to occur in the material package. This problem increases in larger packaging sizes, and it is related to the uneven distribution of internal stress. In order to study the internal stress distribution law of the wound package, it is necessary to analyze and discuss the mechanical behavior of the winding process. In this paper, a winding model based on thick-cylinder theory was established to deduce the internal stress distribution and change law of the wound package. Polypropylene melt-blown nonwoven fabric was used as the test material; it showed no deformation residue after the stretching test, which was the allowable stretching conditions of the nonwoven fabric from the low-strain stretching experiment. Based on the material mechanical properties, three tension control strategies (namely constant tension, constant torque, and taper tension winding) of the winding tension were analyzed and the variation law of winding stress was described. The internal stress of the ideal packaging was premised, which was determined as the winding tension control curve under even internal tension and can be called equal internal tension winding. The results showed that the properties of materials have a significant impact on packaging quality, and equal internal tension winding can effectively improve packaging quality and size. The research results can provide some reference for tension control in the winding process of nonwoven fabric or other textile materials.

Robust constrained tension control for high-precision roll-to-roll processes

Tension control is critical for maintaining good product quality in most roll-to-roll (R2R) production systems. Previous work has primarily focused on improving the disturbance rejection performance of tension controllers. Here, a robust linear parameter-varying model predictive control (LPV-MPC) scheme is designed to enhance the tension tracking performance of a pilot R2R system for deposition of materials used in flexible thin film applications. The performance of a tension controller may degrade due to disturbances associated with model uncertainties and the slowly-changing dynamics in R2R systems. We introduce a method that separately treats these two sources of disturbance. The controller utilizes an incremental model to eliminate the errors caused by the mismatch between the nominal model and the actual system. A tube-based MPC formulation combined with scheduled parameters adequately updates models and corrects for the time-varying dynamics. Constraints on the rated motor torque are incorporated in the MPC to maintain the controller reliability and avoid machine failures. We illustrate the operation of our control algorithm through simulation of an actual R2R system. The controller outperforms the benchmarks in terms of fast transient response and offset-free tension tracking. It also demonstrates immunity from variations due to parametric uncertainties.