Coupling Control Strategy Research Articles

Bend-twist adaptive control for flexible wind turbine blades: Principles and experimental validation

This study proposes a new methodology for optimizing the power curve of a wind turbine at low wind speeds. The principles of bend-twist coupling and the mechanism of energy exchange between the structure and inflow are analyzed. For the blade’s geometric nonlinearity, the virtual displacements and strain fields are described using the Green-Lagrange strain theorem, retaining third-order terms in the energy expressions. The equations of motion are derived using Hamilton’s principle. The bend-twist coupling effects and large deformations of the blade are analyzed using the Updated Lagrange method. Notably, the angle of attack for a single blade section is influenced by bend-twist deformation, causing variations in the rotor’s maximum power coefficient from its optimal value. Additionally, the projection length of the blade, influenced by centrifugal forces, also affects the bend-twist deformation. Based on these findings, an aero-elastic coupling control strategy, termed “Bend-twist Adaptive Control”, is proposed and validated through experiments. The results demonstrate that the proposed control strategy could increase annual power production by 2.3 %. These conclusions offer a promising outlook for future wind turbine blade design and power optimization.

Self-Adaptive Resonance Technology for Wireless Power Transfer Systems to Eliminate Impedance Mismatches

Impedance mismatching can severely decrease the power transmission capacity or even invalid the control logic of wireless power transfer (WPT) systems. To eliminate the impedance mismatch caused by various factors, such as resonant parameter drift, coupling structure misalignment and control strategy, a self-adaptive mistuning correction circuit and corresponding parameter design rules are proposed to ensure the WPT system consistently operates under resonant state, accompanying the optimal power transfer ability. Moreover, a reactive compensation circuit that can create an auxiliary voltage source by the absorbed reactive power that is introduced by impedance mismatching is designed. This source can generate a new current on the coil to bring the mismatched input current back to the resonant state, according to the current superposition principle. Unlike passive impedance network that require high parameter precision and active impedance matching strategies equipped with detection and control circuits, the proposed approach can self-adaptively eliminate either undesired capacitive or inductive reactance with two additional switches and an energy-storage capacitor, improving impedance adjusting rate and providing better system robustness. The simulations and experiments are in good agreement with the theoretical analysis. This study has potential applications in harsh environments where the system impedance and coupling strength are continuously disturbed.

Multi-motor average deviation coupling control strategy based on hyperbolic convergence law high-order sliding mode control using extended state sliding mode observer

This paper aims to develop a multi-motor synchronous drive control system for the direction of the width of the lifting arm of a catamaran. Firstly, we establish a mathematical model of permanent magnet synchronous motor and introduce the composition of AC servo control systems. We then analyze the sources of control interference in multi-motor drive systems. Based on the mean deviation coupling control strategy of multi-motor synchronous control, we design a speed tracking controller and a speed synchronization controller using hyperbolic convergence law high-order sliding mode control. Then, we design an extended state sliding mode observer to estimate the unmodeled dynamics of the system in real time. We prove the global stability of the controller using Lyapunov stability theory. Finally, the control model is simulated, and the results confirm the effectiveness of the multi-motor synchronization control method based on the hyperbolic convergence law of higher-order sliding mode control. The control method effectively mitigates the jitter associated with traditional sliding mode control and demonstrates improved synchronization and tracking performance.

Adaptive multi‐level differential coupling control strategy for dual‐motor servo synchronous system based on global backstepping super‐twisting control

AbstractA new dual‐motor servo steering system with improved reliability and safety is proposed. But, despite the advantages of the proposed servo system, it is strongly coupled, non‐linear and multivariable, where the biggest challenge lies in its tracking and synchronization control. To improve the tracking and synchronization control performance of the proposed servo system, a tracking and synchronization control strategy based on backstepping super‐twisting control and multi‐level differential coupling is presented. First, a parallel model of the dual‐motor is established. Then, backstepping and super‐twisting control algorithms are integrated while adaptively optimizing key parameters to ensure the robustness and tracking performance of each motor. After that, an angular synchronization controller with multi‐level differential coupling and backstepping super‐twisting algorithm is proposed to compensate for the synchronization error of the dual‐motor system caused by parameter uncertainty. Finally, the simulation is carried out using Simulink to verify the effectiveness of the proposed control strategy.

Longitudinal and lateral stability control for autonomous vehicles in curved road scenarios with road undulation

PurposeThis research aims to present a novel cooperative control architecture designed specifically for roads with variations in height and curvature. The primary objective is to enhance the longitudinal and lateral tracking accuracy of the vehicle.Design/methodology/approachIn addressing the challenges posed by time-varying road information and vehicle dynamics parameters, a combination of model predictive control (MPC) and active disturbance rejection control (ADRC) is employed in this study. A coupled controller based on the authors’ model was developed by utilizing the capabilities of MPC and ADRC. Emphasis is placed on the ramifications of road undulations and changes in curvature concerning control effectiveness. Recognizing these factors as disturbances, measures are taken to offset their influences within the system. Load transfer due to variations in road parameters has been considered and integrated into the design of the authors’ synergistic architecture.FindingsThe framework's efficacy is validated through hardware-in-the-loop simulation. Experimental results show that the integrated controller is more robust than conventional MPC and PID controllers. Consequently, the integrated controller improves the vehicle's driving stability and safety.Originality/valueThe proposed coupled control strategy notably enhances vehicle stability and reduces slip concerns. A tailored model is introduced integrating a control strategy based on MPC and ADRC which takes into account vertical and longitudinal force variations and allowing it to effectively cope with complex scenarios and multifaceted constraints problems.

Energy Coupling Control of Bridge Crane Based on Adaptive Fuzzy Strategy

Aiming at the problem that the traditional PID algorithm omits the nonlinear characteristics of the bridge crane system and the control effect is limited, this paper puts forward an energy coupling control strategy based on an adaptive fuzzy strategy. The coupling generalized semaphore for the Lyapunov controller is obtained by solving the dynamic equation of the bridge crane with energy, and the controller parameters are adjusted by using an adaptive fuzzy strategy. The simulation results show that the designed controller has a better anti-sway effect than the traditional PID controller.

Design and optimization of thermal strategy to improve the thermal management of proton exchange membrane fuel cells

This paper briefly recommends the working principle of the cooling system of the fuel cell engine (PEMFC), studies the control strategy of the thermostat in the cooling system, which couples the electric heater to shorten the water temperature fluctuation and save time. Cooling PEMFC is a challenge due to the small temperature differences between the stack and the environment. The fluctuation of water temperature and time transformation will lead to the change of system power, and further impact on the system's dynamic performance, reliability and life. Firstly, the simulation and experimental verification of cooling system of 30 kW fuel cell engine are presented. The influence of mechanical paraffin thermostat and electronic thermostat with certain control logic on the outlet temperature of the engine system stack is contrasted. Severe water temperature fluctuations will decrease the life of the system. Furthermore, the PID control and fuzzy PID control of temperature control valve are adopted, and the control method of coupling electric heater is used to solve the temperature fluctuation when the water temperature at the outlet of the stack is mixed. The results indicate that compared with the paraffin thermostat and PID controller, the fuzzy PID controller can obviously decrease the temperature fluctuation during the mixing of water temperature. Further, in different external environments, the fuzzy PID control coupling electric heater can reduce the temperature difference fluctuation to 0.5 °C when the system mixes large and small circulating water temperatures. The optimized coupling control strategy can decrease the water temperature fluctuation of the cooling system, thereby optimizing the temperature management of the cooling system, and significantly extending the power and reliability of the system.

Study on large deformation and failure mechanism of deep buried stratified slate tunnel and control strategy of high constant resistance anchor cable

Aiming at the significant deformation problem of deep buried stratified soft rock tunnel, taking the No.3 inclined shaft of Muzhailing tunnel as background, the deformation and failure mechanism of the tunnel and the control strategy of high constant resistance anchor cable are studied. The deformation and failure mechanism of stratified tunnel surrounding rock is studied by physical model test, including the tunnel's temperature field, strain field, and displacement field from excavation to failure. Lateral stress significantly influences the deformation of the surrounding rock of the horizontal stratified tunnel. The surrounding rock of the tunnel forms a dumbbell-shaped tensile stress zone under the action of stress. The high tensile stress of the roof and floor leads to dislocation and layer separation, which causes floor heave failure and temperature change. The indoor tensile test verified the super strength characteristics and large deformation of the high constant resistance anchor cable. Based on the excavation compensation method and the coupling control mechanism of high constant resistance long and short anchor cables, a new high prestress constant resistance coupling control strategy is proposed. The numerical simulation and field test studies according to the new design are presented, which show that the high constant resistance anchor cable coupling support significantly reduces the tensile stress zone, effectively controls the deformation of tunnel surrounding rock, and avoids the damage of supporting structure and the cracking and deformation of the lining. The research results can provide a reference for constructing and supporting deep-buried, stratified soft rock tunnels.

Power coupling and grid-connected support control of the PV/ESS power generation system with virtual inertia

Under virtual synchronous control, the photovoltaic energy storage grid-connected system can realize synchronous grid connection. However, the power coupling relationship between units needs to be analyzed to reduce additional operation risks and improve the support performance of virtual synchronous control. In this paper, the definition of virtual inertia of the energy storage device is described, and the power coupling relationship between the virtual synchronous generator and synchronous generator is analyzed by establishing a small-signal model of photovoltaic energy storage grid-connected power generation system. The influence of the power coupling control coefficient on the static and transient stability of the grid-connected system is analyzed by the extended equal area rule and eigenvalue method. Based on this, a power coupling control strategy is proposed to improve inertia and damping support performance. Finally, a grid-connected power generation simulation system with a high proportion of photovoltaic energy storage is built to test and verify. The results demonstrate that the proposed control can reduce the risk of power oscillation induced by virtual inertia and improve the grid-connected system’s frequency support and power oscillation suppression ability.

Distributed Permanent Magnet Direct-Drive Belt Conveyor System and Its Control Strategy

The long-distance traditional belt conveyor driven by a single high-power motor has the problems of excessive tension increments and sharp fluctuations in speed and tension. This paper designs a distributed permanent magnet direct drive belt conveyor system. The dynamic model of the conveyor belt unit and the permanent magnet motor is analyzed. The multi-motor ring coupling control strategy and the double sliding film direct torque control strategy of the belt conveyor system are formulated. The mechanical-electrical coupling dynamic model of the belt conveyor system is built. Using MATLAB/Simulink modeling and simulation, the vector control strategy and electromechanical coupling dynamic behavior of the traditional belt conveyor system and the distributed permanent magnet direct drive belt conveyor system under light load start-up and local variable load operation conditions are studied. The results show that: the distributed permanent magnet direct drive belt conveyor system significantly reduces the peak of conveyor belt tension increment; the time spent under the starting light-load operation condition is shorter, and the fluctuation amplitude of speed and tension is smaller; it is possible to reduce the speed and tension fluctuation range of the conveying system and improve the robustness of the conveying system under local variable load conditions. Experiments have verified that increasing the number of drive motors in a conventional belt conveyor can suppress the disturbance caused by local load changes, and the distributed permanent magnet direct-drive belt conveyor has better dynamic regulation performance.

DP-Climb: A Hybrid Adhesion Climbing Robot Design and Analysis for Internal Transition

This paper proposes a double propeller wall-climbing robot (DP-Climb) with a hybrid adhesion system based on the biomimetic design principle to address the problems of single adhesion-powered wall climbing robots (WCRs). Such problems include poor maneuverability and adaptability to orthogonal working surfaces with different roughness and flatness, weak flexibility of ground-wall transition motion, and easy stand stilling of transition,. Based on the clinging characteristics of different creatures, the hybrid system combines the rotor units’ reverse thrust, the drive wheels’ driving torque, and the adhesion force offered by the coating material to power the robot through a coupled control strategy. Based on the Newton–Euler equations, the robot’s kinematic characteristics during the ground-wall internal transition motion were analyzed, the safe adhesion conditions were obtained, and a dynamics model of the robot’s ground-wall transition was established. This provided the basis for the coupling control between different power units. Finally, an internal transition PID control strategy based on DP-Climb was proposed. Through mechanical and aerodynamic characteristic experiments, it is verified that the robot’s actual output pulling force can meet the transition motion demand. The experimental results show that the proposed strategy can enable the DP-Climb to complete the ground-wall mutual transition motion smoothly with a speed of 0.12 m/s. The robot’s maximum wall motion speed can reach 0.45 m/s, which verifies that the hybrid adhesion system can flexibly and quickly reach the specified position in a target area flexibly and quickly. The robustness and adaptability of WCR to complex application environments are improved.

An AC-DC Coupled Droop Control Strategy for VSC-Based DC Microgrids

Droop control is a common strategy to facilitate appropriate load sharing among different sources in dc microgrids (MGs). To endow simple control structure and fast bus voltage transient response to dc MGs with multiple voltage source converters (VSCs), this article proposes an ac–dc coupled droop control strategy, which yields the ac current (active components <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i_d</i> ) reference of the VSCs inner loop directly in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> frame. In this way, the ac current ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i_d</i> ) of the VSCs inner loop is directly linked to the load sharing performance of the dc MG. In contrast with the existing droop approaches, the proposed method does not require any extra outer dc voltage/current proportional--integral (PI) loops, which avails fast bus voltage dynamics during transients. Systematic evaluation of its performance is conducted by small-signal modeling and subsequent analysis from a single-source operation to a multisource operation. The effects of inner current loop bandwidth and droop gain on system stability are studied while feeding constant power loads. The theoretical analysis has been validated by both simulation and experimental results.

Control strategy optimization of plug-in hybrid electric vehicle based on driving data mining

SDP (Stochastic Dynamic Programming) control strategy can mine the travel data of drivers, so that the energy-saving potential of vehicles could be improved. However, there are two problems need to be solved in the current SDP: firstly, the analysis and construction method of driver’s typical driving cycle is not clear; secondly, the adaptability of SDP algorithm to a typical driving cycle is insufficient. To solve the above problems, a driving cycle construction method for off-line SDP solution is proposed, which is based on “analysis, dimension reduction and clustering” process. In addition, a coupled control strategy (ECMS-SDP) based on driving conditions identification is developed. Because it is difficult to predict the driving conditions in real time, the working part of the coupled control strategy is calculated by the method of improved random forest. The simulation results show that ECMS-SDP control strategy can save 8%–15% fuel on average compared with CD-CS control strategy, and can save 4%–7% fuel on average compared with ECMS control strategy. The results prove that the ECMS-SDP coupled control strategy can respond well to the changing driving environment, and the fuel economy of vehicles is enhanced.

Coupling control of superheat and nitrogen oxides for gas engine heat pump

Gas engine heat pump (GEHP) is gradually developing due to the high energy efficiency. However, the gas engine is easily disturbed by load fluctuation, which affects the stability of GEHP operation and causes higher nitrogen oxides (NOx) emission concentrations. Therefore, an efficient control method is necessary to ensure system stability, improve energy efficiency and reduce NOx emissions. In this paper, a coupling control strategy of superheat and NOx is proposed. The results show that the superheat can maintain stability with the small overshoot and adjustment time of less than 400 s when the engine speed changes. When the superheat setting value changed continuously, the superheat overshoot and error are less than 0.5 °C and the adjustment time is about 100 s. Meanwhile, the system outlet temperature is stable, the overshoot is less than 1 °C. The amplitude variation of the refrigerating capacity is similar to the amplitude variation of the superheat. The variation range of total heat capacity is greater than that of refrigerating capacity. In addition, the performance and emission of the GEHP are respectively studied when the superheat is 4 °C and 7 °C, at the optimum excess air coefficient. The NOx emissions are always below 100 ppm, but the primary energy ratio (PER) is higher under the superheat of 4 °C. Therefore, the proposed coupling control strategy can achieve good stability, excellent performance and emission characteristics.

Comparison of different load-following control strategies of a sCO2 Brayton cycle under full load range

The supercritical CO2 Brayton cycle has been regarded as a promising next-generation power conversion system owing to its flexibility and high efficiency. Dynamic performance and control strategy are essential research topics when systems are subjected to various load demands. Inventory control has been proven as a very effective load control method and valve controls have the potential to meet wider load demands. While few studies have focused on the differences in efficiency and system performance under different control strategies. In this study, a dynamic model of recompression supercritical CO2 Brayton cycle is proposed, and its components are carefully validated. Moreover, an inventory and anti-surge coupled control strategy is proposed to achieve better control performance. Under the premise of considering system security, various control strategies meeting 0%–100% load range are compared. The primary objective of this study is to reveal the differences in efficiency and dynamic performance of various control strategies in the full load range, to provide a basis for the selection of control strategies in off-design conditions. The results demonstrate that inventory and anti-surge coupled control allow safe tracking loads as low as 0%, and it provided an absolute advantage in terms of efficiency compared to valve controls.

Research on cooperative control strategy of multi-motor system based on fuzzy inference

General distributed multi-motor control system has a low synchronization performance and a poor coordination control accuracy. In order to improve the deficiencies, the fuzzy control method is used. Firstly, the fuzzy PID controller is designed to improve the control accuracy of a single motor in the control system; Then, aiming at the shortcomings of the traditional deviation coupling structure, an adjacent deviation coupling control strategy based on fuzzy inference and a speed compensator are designed to improve the synchronization performance of the whole control system. The simulation results show that the tracking error of single motor and the synchronization error between motors are greatly reduced.

Rigid-Flexible Coupled Dynamic and Control for Thermally Induced Vibration and Attitude Motion of a Spacecraft with Hoop-Truss Antenna

As space exploration activities are developing rapidly, spacecraft with large antennas have gained wide acceptance in providing reliable telecommunications and astrophysical observations. In this paper, the dynamic responses and control strategy for a spacecraft with a large hoop-truss antenna under solar flux shock are studied. According to the momentum and angular momentum principle, the rigid-flexible coupled rotational dynamic equation and the translational dynamic equation of the system are established, which include the attitude motion of the rigid main body and the vibration of the antenna. Then, a finite element model of the antenna is established to analytically obtain the corresponding vibration modal shape matrix and natural frequencies. Last, the coupled responses for the attitude motion and vibration are investigated. The corresponding control strategy is designed based on a double-loop structure sliding mode control method. The Lyapunov method is used to demonstrate the global asymptotic stability of the system. Simulations verify the effectiveness of the proposed rigid-flexible coupled model and control strategy.

Mean Deviation Coupling Control for Multimotor System via Global Fast Terminal Sliding Mode Control

In view of the shortcomings of the existing multimotor synchronous control strategy, a new method of mean deviation coupling control for multimotor system via global fast terminal sliding mode control is proposed. Firstly, the mathematical model of permanent magnet synchronous motor (PMSM) under a d - q reference frame is established. Next, based on the deviation coupling control, the deviation is calculated by the average speed, and the structure of the deviation coupling control strategy is optimized. The speed controller of the multimotor system is designed based on the global fast terminal sliding mode control (GFTSMC) algorithm to improve the synchronization accuracy of the system. In addition, a load torque Luenberger observer is designed to observe the load in real time. Then, the stability analysis of the controller is carried out by using the Lyapunov function. Finally, a four-motor experimental platform is built to verify the effectiveness of the proposed control strategy.

Dynamic analysis of two-rotor wind turbine on spar-type floating platform

The dynamic response of a two-rotor wind turbine mounted on a spar-type floating platform is studied. The response is compared against the baseline OC3 single-rotor design. Structural design shows how the two-rotor design may lead to a mass saving of about 26% with respect to an equivalent single-rotor configuration. Simulations predict significant platform yaw response of the two-rotor floating wind turbine — about 6 deg standard deviation at the rated operating wind speed. It is shown how the platform yaw response is directly caused by the turbulence intensity at the hub coupled with the transversal distribution of thrust loads on the structure. A coupled control strategy for the rotor-collective blade pitch controller is proposed, in which a simple proportional control mitigating platform yaw motion is superimposed to the baseline OC3 PI controller. Numerical simulations show how platform yaw response is reduced by about 60%, at the cost of mean power loss at below-rated wind speeds of about 100 kW and maximum increase of the rotor-collective blade-pitch angles standard deviation of about 2 deg. Parametric analysis of mooring lines design shows how an equivalent mass density of the line of at least 190 kg/m is needed to avoid vertical loads at the anchors.

Nonlinear Vibration of Manipulator Induced by Coupling Time Delay and Control Strategy

This article uses the theory of Hopf bifurcation to study the stability[1-2] of nonlinear manipulator system with time delay built by Spong. The period vibration, almost periodic vibration and chaos motion are stabilized by the controllers designed in the article, which is achieved by changed the polynomial u in the dynamic of manipulator. It is proved that the controllers in this article are useful by calculating the eigenvalues of the linear form of the dynamic of manipulator, which are expressed in the complex plane, according to the stability theory[2].