Tension Control Strategy Research Articles

Modeling and control of perturbation torques and mass distribution impact on a tethered system for a 12U CubeSat in sun-synchronous orbit

Tethered CubeSat systems are characterized by momentum exchange and gravity gradient stabilization, and encounter stability challenges, especially with shorter tethers in highly inclined and eccentric orbits. This study investigates the libration dynamics of a 12U CubeSat in its stowed configuration, which separates into two satellites connected via tether, throughout its deployment, station-keeping, and retrieval phases. Two deployed configurations, symmetrical 6U-6U, and asymmetrical 8U-4U connected by a non-conductive tether with a maximum length of 100m are analyzed. The study accounts for perturbations including Earth’s oblateness, atmospheric drag, solar radiation pressure, and lunisolar gravitation, modeling the tether as a rigid, extendable rod and the satellites as lumped masses. The translational and rotational dynamics are decoupled, assuming the system’s center of mass follows an unperturbed Keplerian Sun-synchronous orbit at altitudes between 400 and 600km. A tension control strategy based on Lyapunov’s direct method and supplemented by external actuation torques is explored. Results show high orbit eccentricity significantly affects the maximum in-plane libration angle. The 6U-6U system experiences smaller disturbance torques but greater tether tension variations than the 8U-4U system. Both configurations exhibit larger in-plane oscillations compared to near-zero out-of-plane oscillations, nonetheless, eclipse passages exacerbate the out-of-plane libration of the 8U-4U system. Relative stability is maintained during deployment, however, retrieval is chaotic, with notable oscillations in libration angles and tether tension. The tension control strategy effectively dampens oscillations during retrieval but loses effectiveness as tether tension approaches zero at retrieval’s conclusion. External actuation torques, ranging from 1-2mNm for deployment to 15mNm for retrieval, complement tension control.

Adaptive RISE Control of Winding Tension with Active Disturbance Rejection

A winding system is a time-varying system that considers complex nonlinear characteristics, and how to control the stability of the winding tension during the winding process is the primary problem that has hindered development in this field in recent years. Many nonlinear factors affect the tension in the winding process, such as friction, structured uncertainties, unstructured uncertainties, and external interference. These terms severely restrict the tension tracking performance. Existing tension control strategies are mainly based on the composite control of the tension and speed loops, and previous studies involve complex decoupling operations. Owing to the large number of calculations required for this method, it is inconvenient for practical engineering applications. To simplify the tension generation mechanism and the influence of the nonlinear characteristics of the winding system, a simpler nonlinear dynamic model of the winding tension was established. An adaptive method was applied to update the feedback gain of the continuous robust integral of the sign of the error (RISE). Furthermore, an extended state observer was used to estimate modeling errors and external disturbances. The model disturbance term can be compensated for in the designed RISE controller. The asymptotic stability of the system was proven according to the Lyapunov stability theory. Finally, a comparative analysis of the proposed nonlinear controller and several other controllers was performed. The results indicated that the control of the winding tension was significantly enhanced.

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.

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.

Spin deployment of Hub-Spoke tethered satellite formation with sliding mode tether tension control

This work develops a tension control strategy for deploying an underactuated spin-stable tethered satellite formation in the hub-spoke configuration. First, the Lagrange equation is used to model the spin-deployment dynamics of the tethered satellite formation. The central spacecraft is modeled as a rigid body, and the tethered subsatellites are simplified as lumped masses. Second, a pure tension controller has been proposed to suppress the tether libration motion in the deployment without thrusting at the subsatellites. A nonlinear sliding mode control is introduced in the tension controller for the underactuated system to suppress the periodic gravitational perturbations caused by the spinning hub-spoke tethered satellite formation. The unknown upper bounds of the perturbations are estimated by adaptive control law. The bounded stability of the closed-loop tension controller has been proved by the Lyapunov theory. Finally, numerical simulations validate the effectiveness and robustness of the proposed controller, i.e., tethers are fully deployed stably to the desired hub-spoke configuration.

Modeling and Adaptive Tension Control of Chain Transmission System With Variable Stiffness and Random Load

In the fully mechanized mining face, proper chain tension of chain transmission system is of great significance in reducing the failure rate and improving the service life of scraper conveyor. However, the disturbance caused by random load and variable stiffness makes it very difficult to control chain tension. An adaptive tension control scheme combining a neural command filtering backstepping algorithm and online identification is proposed in this article based on a novel tension model. First of all, the proposed tension model is represented by a linear regression part and a nonlinear mapping part, which effectively reflects the chain transmission characteristics and avoids the full measurement of each chain ring. Then, Levant's differentiator and state observer are used to expand input variables for identification algorithm and neural networks estimation. To avoid the adverse effect of random load on parameter adaption, stiffness online identification algorithm is employed in improving the tension tracking performance. To compensate for nonlinear mapping part and uncertain nonlinearity caused by random load, neural adaptive estimator is effectively integrated with the robust integral term in backstepping design. Moreover, Lyapunov stability of the proposed controller is guaranteed. Finally, comparative experimental results of six controllers are completed to verify the effectiveness of the proposed controller in the static and random load mode.

Analysis of Tension Instability and Research on Stability Control Strategy in the Process of Rapier Loom Weaving

Tension control is very important for the intelligent control system of rapier looms because stable tension guarantees a tight fabric structure, moderate elasticity and good forming. To solve the problems of low-tension measurement accuracy of the existing rapier loom, the complex structure of the tension control strategy and algorithm, and the high research and development cost, this paper proposes new research from the perspective of high-precision and nonlinear processing of tension detection signals. The median filtering and limiting filtering algorithms are integrated to solve the uncertainty problem caused by the disturbance and fluctuation of the tension signal, and an excellent sample dataset is obtained. The attenuation factor and the number of learning times are introduced to design and adjust the learning rate of the back propagation neural network algorithm. In addition, the overfitting problem of the backpropagation neural network model in the current research process is solved. The experimental simulation results show that the tension detection fluctuation range of this method is 0.8 kg, and the tension detection error is within 0.1%. On the basis of the existing tension control algorithm, the tension detection accuracy is improved, which presents a new research perspective for the wide application of high-precision tension control strategies in rapier looms. It is of great importance to improve the production efficiency and fabric quality of rapier looms.

Design of Insulation Tape Tension Control System of Transformer Winding Machine Based on Fuzzy PID.

With the rapid development of science and technology as well as the comprehensive societal progress, the demand for electricity in all walks of life is also increasing. As is known to all, the mechanical structure and tension control of a transformer winding machine is the key to improving the quality of coil winding, due to coil winding being generally considered the core technology of transformer manufacturing. Aiming at the synchronous winding control problem of the conductor and insulating layer of the transformer winding machine, this paper presents a mechanical structure and tension control scheme of a new type of transformer winding machine. Based on the dynamic analysis and modeling of the mechanical structure of the winding machine, the speed control of the main speed roller by the fuzzy PID control rate is implemented initially. Combined with the actual demand of the project, the feasibility and effectiveness of the control target with different tension are verified by the simulation experiment and further compared with the traditional PID control method. The simulation results show that the proposed fuzzy PID control rate can realize the automatic and efficient winding of the transformer winding machine, showing that it is superior to the traditional PID control rate in overcoming the disturbance and controlling effect.

Research on integral separation control of warp tension based on fuzzy parameter optimization

In textile machines, the stability of warp tension is one of the decisive factors for the reliability, stability and product quality of weaving process. In order to meet the improving requirement for weaving efficiency and fabric quality, it is proposed that a fuzzy optimization integral separation PID warp tension control scheme based on process sampling to improve the warp tension control level of loom. Aiming at the problems of time-varying, nonlinear and variable coupling in the warp tension control system of loom, the forming mechanism of warp tension is modeled and analyzed, and the sampling scheme of warp tension based on process is proposed. Based on the periodic change of warp tension at macro level and continuous fluctuation at micro level, the integral separation control and fuzzy optimization theory are introduced to optimize the control effect of the control system on the basis of classical PID control algorithm. Finally, the simulation and experiment show that the scheme can improve the tension controls performance and effectively reduce the tension error fluctuation.

Analysis, planning and control for cooperative transportation of tethered multi-rotor UAVs

The calculation of available wrench set of tethered multi-rotor UAVs is more challenging than that of the traditional cable-driven parallel robots (CDPRs) with fixed anchor points, due to the bounded thrust, motion acceleration and external disturbance acting on multi-rotor unmanned aerial vehicles (UAVs). To our best knowledge, this is the first work to investigate the dynamic available wrench set. We define an index called capacity margin to evaluate the robustness of the quasi-static motion for different system configurations and to represent the available maximum acceleration of the payload. Moreover, the feasible trajectories of multi-rotor UAVs are optimized using a tension distribution algorithm to accomplish the manipulation of the payload. Without the need of centralized ground control station, payload states and UAVs' velocity information, a decentralized output feedback control based on fixed-time extended state observer (ESO) is developed for the group of multi-rotor UAVs. The rigorous proof of stability of the closed-loop system is conducted. Finally, numerical simulations and comparative experiments are demonstrated to validate the proposed tension distribution algorithm and control strategy.

Nonlinear Analysis of Discrete-Time Sliding Mode Prediction Deployment of Tethered Space Robot

This article proposes a discrete-time sliding mode prediction controller for deploying tethered space robot, and tension control strategy in deployment carries a limited input nature for the underactuated system. A linear component involving swinging angle and a fractional power component involving length combine to establish a novel discrete-time quasi-terminal sliding surface for underactuated dynamics. The corresponding reduced-order system is decoupled by using a hierarchical constrictive analysis methodology to generate an equivalent relationship between length and swinging angle, and the stability of the entire system is governed by multidelay system of length. The D-decomposition technique is employed to deduce that the steady-state error of length is ultimately uniformly bounded. The optimal reaching law is designed based on the sliding mode prediction algorithm, which can guarantee that the prediction correction converge to zero, and the sliding surface with a small boundary layer can hence be established in finite steps under the limited tension control with a modified input compensation sequence. Simulation results verify the correction of stability analyses on dynamics and the steady-state behavior of the sliding mode, and from the numerical results, the proposed method can save time for deploying tethered space robot by only using tension than normal discrete-time sliding mode control.

Modeling of Tension Control System with Passive Dancer Roll for Automated Fiber Placement

The fiber tension should be kept constant during the automated placement of fiber prepreg. The velocity of the fiber placement end-effector moving on complex aircraft panel mould surface varies rapidly, which greatly disturbs the precision of tension control. This paper proposes a tension control strategy combining active control and passive control. The pay-off motor controls the fiber tension directly and a passive dancer roll is designed theoretically as the equipment for attenuation of tension disturbance to realize the real-time compensation of low-frequency velocity variations. The nonlinear model of tension control system, which includes the dynamics of the passive dancer roll, is established, and the effect of dancer roll parameters on its disturbances attenuation performance is analyzed. The controller is designed using the H∞ mixed sensitivity method. An experimental tension control precision about 2% is obtained at stable placement speed on the automated fiber placement (AFP) machine. The experiments also indicated that the tension would not vary over 1 N at a maximum acceleration of 4 m/s2.

Effect of different fermentation strategies on Bacillus thuringiensis cultivation and its toxicity towards the bagworm, Metisa plana Walker (Lepidoptera: Psychidae)

The effect of batch and fed-batch fermentation on the cultivation performance of Bacillus thuringiensis was investigated using a 5-l stirred tank bioreactor. Significantly higher viable cell count (> 1.5 × 1012 CFU/ml) was obtained in the fed-batch compared to batch fermentation (1.4 × 1012 CFU/ml). Glucose feeding during the fermentation seemed to enhance cell growth but failed to enhance the sporulation rate. It was found that sporulation and δ-endotoxin synthesis in fed-batch fermentation could be enhanced by the application of optimal dissolved oxygen tension (DOT) control strategy without affecting the cell growth. Fed-batch cultivation with feeding at the exponential growth phase where the DOT was switched from 80 to 40% at 12 h of cultivation recorded the highest spore count of 7.1 × 1011 spore/ml. Cultures obtained from batch cultivation, as well as fed-batch cultivation with feeding at lag or exponential growth phase and the application of optimal DOT control strategy, recorded the presence of δ-endotoxin; however, none was detected in intermittent fed-batch fermentation. Bioassay data against the bagworm Metisa plana Walker (Lepidoptera: Psychidae) recorded the highest corrected mortality (80%) at 7 days of treatment (DAT), using the culture obtained from fed-batch cultivation with feeding during the exponential growth phase, and the DOT was switched from 80 to 40% at 12 h of cultivation. It is important to note that all cultures containing δ-endotoxin exhibited 100% mortality towards M. plana at 14 DAT.

Velocity-Sensorless Decentralized Tension Control for Roll-to-Roll Printing Machines

This paper presents a velocity-sensorless decentralized tension control scheme without true machine parameter dependence for roll-to-roll printing machines. Both the nonlinear nature and parameter uncertainties are taken into account the development task. As the first merit, the proposed observer eliminates the requirement of velocity feedback without any plant information even the nominal parameters. The introduction of the active-damping with the estimated state reduces the closed-loop system order to 1 by the pole-zero cancellation using the specified feedback gains. Finally, the disturbance observer (DOB) replaces the regulation error integrators with the closed-loop robustness improvement against the high-frequency disturbances. The MATLAB/Simulink-based simulations validate the effectiveness of the proposed decentralized scheme.

Sliding Mode Compensation Control for Diaphragm Tension in Unwinding Process of Lithium Battery Diaphragm Slitting Machine

In order to solve the problem of tension control in the actual unwinding process of the lithium battery diaphragm slitting machine, the dynamic model of diaphragm and slitting machine unwinding system is constructed in this paper based on the diaphragm deformation in the unwinding system during the sampling period, in view of the nonlinear system characteristics of the unwinding system and the unstable diaphragm tension caused by the uncertain interference and the inaccurate model in the unwinding process. Considering the unwinding system characteristics of multi-output and strong coupling between outputs, a multi-variable comprehensive sliding surface for balancing unwinding diaphragm tension and unwinding speed, and a sliding mode controller for controlling the diaphragm tension in unwinding process are designed. And the stability of the sliding surface and the controller is proved. The fault-tolerant improvement of the sliding mode controller is carried out for practical engineering application, and the differential tracking disturbance observer is proposed to quickly estimate and compensate the external disturbance of the system. Finally, the results of the comparative experiments verify the effectiveness of the proposed diaphragm tension control scheme.

The Equivalent Sliding Mode Tension Control of Carbon Fiber Multilayer Diagonal Loom

In order to enhance the tension control performance of the carbon fiber multilayer diagonal loom, two control methods based on the yarn warping and the curling control are proposed. The tension control mathematical models of carbon fiber multilayer diagonal loom, the yarn warping control model and the curling control model, are reestablished by the force analysis of the warping and the curling systems. Some technological process movements, such as the opening and the beating-up, are regarded as the disturbances. Based on the equivalent sliding mode control theory, the tension control strategies of the warping and the curling are constructed. Lyapunov method is used to prove the stability of the systems. Simulation results show that both the two methods could control the tension of the yarn, and the control results have good robustness to the disturbances.

Anti-impact tension control strategy for the space-tethered combination after target capture

ABSTRACTAn electromechanical coupling model is established for the space-tethered combination (STC) under microgravity environment after target capture by the tethered robot system (TRS). A linearized dynamic model of the STC is put forward with its controllability and observability as a control system analyzed. A double closed-loop tension control strategy is proposed to mitigate the impact and suing longitudinal vibration caused by the velocity difference between the platform and target. Experiment setup is built on a ground-based flotation platform to investigate the impact of the STC. Results of simulation and experimental validation show that the proposed tension control strategy is responsive and rapid in tension tracking and effectively prevent impact.

Libration suppression of tethered space system with a moving climber in circular orbit

This paper studies the dynamics and libration suppression of a tethered system with a moving climber in circular orbits. The tethered system is modeled by a two-piece dumbbell model that consists of one main satellite, one climber and one end-body connected by two straight, massless and inextensible tethers. A new tension control strategy to suppress the libration of the tethered system due to the moving climber is proposed by reeling in-out tether at the end-body without thrust. The control strategy is implemented with the sliding mode control to suppress the libration angle of the climber to zero by the end of climber’s transfer phase. The numerical results show that the proposed control strategy is very effective in suppressing the libration of the climber in the three-body tethered system with tension control only. Furthermore, cases with limited tension control are examined. It reveals that a longer tether between the climber and the end-body is required to supplement the limited tension in suppressing the libration of the climber.

Wire tension control of an automatic motor winding machine—an iterative learning sliding mode control approach

This paper focuses on active wire tension control of motor winding machines.An ILSMC scheme for wire tension control is developed.A disturbance observer is used to implement sensorless wire tension control.The estimated wire speed is exploited in designing the tension control scheme.The stability and convergence proof of the proposed approach is provided. One of the most crucial factors that affects the winding quality in an automatic motor winding process is the regulation of wire tension. Most commercial automatic motor winding machines use passive devices such as a dancer arm or a hysteresis brake to adjust the wire tension. However, as the winding speed increases, these passive devices may not be able to react quickly enough to maintain constant wire tension and may cause the enameled wire to tremble. In order to cope with the aforementioned problems, this paper conducts an in-depth study on active wire tension control of automatic motor winding machines. In particular, an iterative learning sliding mode control scheme for wire tension control is developed in this paper, while a disturbance observer is employed to estimate the wire tension for the implementation of sensorless wire tension control. Moreover, due to the fact that the motion of the unwind roll is affected by the motion of the enameled wire, the estimated wire speed information is exploited in the design of the tension control scheme to lessen the lag phenomenon. Results of the winding experiments verify the effectiveness of the proposed wire tension control scheme.

Study on the system design and control method of a semi-active heave compensation system

ABSTRACTThe heave compensation system is essential for the installation of subsea equipment. A new semi-active heave compensation system is designed and the control system is analysed, with the aim of solving heave movement problems during deep-water installation. The heave compensation is implemented with a pulley block system and actuated by a compound hydraulic cylinder. The control system can switch between passive compensation mode and semi-active compensation mode. The state-space equations of both modes are set up based on the mechanical and hydraulic system models of the compensation system. With the state-space equations, three control strategies are compared based on the classic Proportion Integration Differentiation (PID) control, and the limitations of PID control are also analysed. In order to avoid defects of the PID controller, the active disturbance rejection control (ADRC) technology is introduced, and a newly developed second-order ADRC controller is applied in the tension control strategy for heave compensation, which results in improved compensation effect.