Synchronous Control Method Research Articles

Dissipativity and synchronization control of quaternion-valued fuzzy memristive neural networks: Lexicographical order method

This article focuses on a dissipativity and synchronization control method for a class of delayed quaternion-valued memristor-based recurrent neural networks. On the basis of Lyapunov functionals, analytical techniques, and novel control algorithms, sufficient conditions are established to achieve dissipativity and synchronization of fuzzy quaternion-valued memristive systems. Moreover, the lexicographical order method is introduced, and can be used to determine the “magnitude” of two different vectors. Finally, corresponding simulation results are provided to show the effectiveness of the proposed method.

Double-Layer Feedback Control Method for Synchronized Frequency Regulation of PMSG-Based Wind Farm

With the rapid growth of wind power penetration in power grid, the system operators need to implement the grid specification of wind farm participating in primary frequency regulation (PFR). In this paper, a double-layer control framework based on permanent magnet synchronous generator (PMSG) is proposed, which can simulate the inertia and droop characteristics similar to thermal units. The top-layer control adopts centralized model predictive control (MPC), while the bottom layer carries out distributed real-time correction control in case of inaccurate MPC prediction. In order to realize fast distributed correction among wind turbines (WTs), a distributed Newton method is proposed, which only requires WTs to exchange limited information with their neighbors on sparse communication network, and has a super-linear convergence rate. By introducing an index of state of energy, this method adequately exploits the kinetic energy of all WTs without loss of security. Compared with the centralized schemes, the dependence on prediction accuracy and data synchronization is greatly reduced. Compared with the distributed schemes, the overall characteristics and computing efficiency can be guaranteed. The simulation results show that the method has satisfactory dynamic performance and reliability, and the system frequency stability is significantly improved under the synchronized control method.

Research on the frequency synchronization control strategy for power system

Power system interconnection makes the modern power system become a huge and complex network, which brings great challenges to frequency stability. The pinning control strategy can reduce the control cost and has a unique advantage. It is one of the most effective method to solve the problem of complex network synchronization. Thus, based on the principle of pinning control strategy, a frequency synchronization control method is proposed to solve the problem of power grid frequency synchronization in this paper. Firstly, in the controller design phase, the pinning control model of a power system is defined based on mathematical model of hydroelectric generator. And the pinning controller is designed based on dynamic compensation LMI sliding mode control. The correctness of the controller is verified by the simulation of a Lorenz chaotic system. Secondly, to determine the controlled generator nodes, an index for evaluating the importance of the generator nodes is defined based on the node deletion method and fuzzy method. Finally, combined with the reality of power network, the external coupling matrix L is calculated based on the successive extended annular domain method and considering the ability of the nodes to receive signals. The feasibility of this method is verified by simulation of the IEEE30-bus system.

Model Decoupled Synchronization Control Design with Fractional Order Filter for H-Type Air Floating Motion Platform.

H-type motion platform with linear motors is widely used in two-degrees-of-freedom motion systems, and one-direction dual motors need to be precisely controlled with strict synchronization for high precision performance. In this paper, a synchronous control method based on model decoupling is proposed. The dynamic model of an H-type air floating motion platform is established and one direction control using two motors with position dependency coupling is decoupled and converted into independent position and rotation controls, separately. For the low damping second-order oscillation system of the rotation control loop, a new fractional order biquad filtering method is proposed to generate an antiresonance peak to improve the phase and control gain of the open loop system, which can ensure system stability and quick attenuation for external disturbances. In the multiple-degree-of-freedom decoupled control loops, a systematic feedback controller design methodology is proposed to satisfy the given frequency domain design specifications; a feed-forward control strategy is also applied to compensate the disturbance torque caused by the platform motion. The simulation and experimental results demonstrate that the proposed synchronization control method is effective, and achieves better disturbance rejection performance than the existing optimal cancellation filtering method and biquad filtering method.

Adaptive Synchronization Control and Parameters Identification for Chaotic Fractional Neural Networks with Time-Varying Delays

In this paper, the adaptive synchronization control and synchronization-based parameters identification method for time-varying delayed fractional chaotic neural networks are proposed. Based on the adaptive control with suitable update law and linear feedback control, an analytical, rigorous, and simple adaptive control method is given, which can make two coupled fractional-order delayed neural networks achieve synchronization. In addition, the uncertain system parameters can also be identified along with the realization of synchronization. The speed of synchronization and parameter identification can be adjusted by selecting appropriate control parameters. Besides, the proposed method is very easy to accomplish in reality and has strong robustness against external disturbances. Finally, the numerical simulations are put into practice to illustrate the rationality and validity of theoretical analysis.

Research on active control method of rotor blade synchronous vibration based on additional secondary excitation forces

In this paper, a synchronous vibration control method was proposed to avoid the high-cycle fatigue fracture of aeroengine rotor blade. Firstly. The harmonic force, causing synchronous vibration, was derived by Fourier series expansion by the mean of simplifying the aerodynamic exciting forces into the periodic rectangular pulse wave forces. It was found that the synchronous vibration can be controlled by adjusting the primary excitation forces parameters. Based on this, the additional secondary excitation forces were introduced to control the synchronous vibration caused by primary excitation forces. Secondly, the influences of the number, position, direction, duration of additional secondary excitation forces and the phase difference between additional secondary excitation forces and primary excitation forces on the synchronous vibration control were obtained through theoretical analysis, which was simulated and verified by a single-degree-of-freedom model. Thirdly, a high-speed straight blade test bench was established, and the feasibility of the method in controlling synchronous vibration of rotor blade was proved by adding additional magnet excitation forces on the basis of fixed magnet excitation forces. Finally, the suppression strategy of synchronous vibration of rotor blade by introducing additional secondary excitation forces was given. It can provide theoretical and technical support for effectively controlling the synchronous vibration amplitude and avoiding the high-cycle fatigue fracture of rotor blade in engineering practice.

Synchronization of Fractional-Order Chaotic Systems with Model Uncertainty and External Disturbance

This paper is concerned with complete synchronization of fractional-order chaotic systems with both model uncertainty and external disturbance. Firstly, we propose a new dynamic feedback control method for complete synchronization of fractional-order nominal systems (without both uncertainty and disturbance). Then, a new uncertainty and disturbance estimator (UDE)-based dynamic feedback control method for the fractional-order systems with both uncertainty and disturbance is presented, by which the synchronization problem of such fractional-order chaotic systems is realized. Finally, the fractional-order Lorenz system is used to demonstrate the practicability of the proposed results.

Position domain control technology for six-joint robots

In the context of the rapid development of intelligent manufacturing, high-precision motion control of industrial robots has attracted increasing research attention. High-speed and high-precision motion control is a development trend associated with the current industrial robots. Industrial transformation and upgradation can be accelerated only via the independent research and development of robot core technologies, including robot high-precision control systems, ensuring the transition of the manufacturing industry in China toward intelligent and digital development. Currently, the contour tracking error associated with majority of the multiaxes CNC machine tools and multijoint industrial robots is a common problem. A good tracking performance can be achieved in time with respect to each joint axis when the space trajectory of the serial multijoint industrial robot changes under multiaxes linkage. The ideal contour trajectory cannot be fully ensured because of the mechanical and electrical hysteresis effects. Therefore, the synchronization of the motion of each servo axis in the geometric space is very important. In this paper, the existing kinematics and dynamics of industrial robots were combined with the traditional PID control theory for studying position domain control algorithm of the six-joint robot to resolve the problem of low accuracy associated with the robot end profile, which can be attributed to the lag between the motion instruction and the actual position. The algorithm uses the method of real-time establishment of the master–slave motion relation for controlling the spatial contour trajectory of the robot. It further transforms the synchronization control method of each servo joint in the time domain into the master–slave follow control method of each servo joint in the position domain. While realizing synchronization control in the position domain, PD control based on position domain was introduced to reduce the following error of the master–slave following control, improving the overall accuracy of the contour motion of the robot end. The method proposed in this paper has been tested on the Linux CNC numerical control system with a company’s HSR-JR605 robot, indicating that the position of the domain control method employed positively affects the accuracy of six articulated robot space trajectory.

Command Filtered Adaptive Backstepping Control for Dual-Motor Servo Systems With Torque Disturbance and Uncertainties

In dual-motor servo systems, several factors seriously affect the tracking performance especially in high-speed and high-accuracy situations, which include machinery flexibilities, torque disturbance, unmodeled dynamics, and motor parameter differences. Given these factors, this article investigates the command filtered backstepping synchronization control (CFBSC) method for a servo system driven by two motors synchronously. Command filters are used to deal with the virtual control signals in backstepping design process to avoid the computational burden causing by repeated derivatives, and a compensation system is applied to reduce the tracking error. Adaptive control is used to compensate the torque disturbance and unmodeled dynamics. In addition, the speed and torque synchronization control signals are designed to guarantee high synchronization performance. The stability of the dual-motor servo system is proved. And the effectiveness of the proposed controller is validated through experiments.

Coordination dynamics and model-based neural network synchronous controls for redundantly full-actuated parallel manipulator

Redundantly full-actuated parallel manipulator takes number of actuations exceeding its degree of freedom, and actuation coordination makes its basis of stable operation. This paper studies the coordination dynamics of general redundantly full-actuated parallel manipulator and derives coordination dynamics models for driving force coordination and internal force regulation respectively. Associated with coordination dynamics models, two neural network synchronous control methods are proposed for each situation correspondingly. Self-learning synchronous algorithms for those methods are designed additionally. Manipulator 6PUS+UPU is taken as a prototype for co-simulations and experiments. Results reveal that the two methods proposed above could improve actuation coordination and internal force precision of redundantly full-actuated parallel manipulator respectively. This paper provides new dynamics-based control methods for the research and control application of parallel manipulator with redundant actuation.

Virtual Synchronous Generator and SMC-Based Cascaded Control for Voltage-Source Grid-Supporting Inverters

The voltage-source grid-supporting inverters (GSIs) are important to establish and support the frequency and voltage of a microgrid (MG) in both islanded and grid-connected modes. Traditionally, a cascaded control strategy that includes an external droop-based control loop and an inner proportional-integral (PI)-based voltage and current control loop is adopted to control a GSI, which barely shows inertia and limited control performance. In this article, a novel cascaded control strategy is proposed for a GSI. In the external loop, a VSG-based control strategy is adopted to increase the frequency stability of the MG, and a novel synchronization control method that does not use a complex PLL unit is proposed to satisfy the plug-and-play requirements of a GSI. In the inner voltage and current control loop, this article proposes an SMC-based vector control strategy which uses the fixed switching frequency and inherits the robustness and fast response speed of the SMC control. Both simulation and experiments demonstrate the effectiveness and improved performance of the proposed control strategy.

Accurate physical modeling and synchronization control of dual-linear-motor-driven gantry with dynamic load

To achieve high-accuracy tracking of a dual-linear-motor-driven (DLMD) gantry, high-level synchronization between redundant actuators becomes a non-negligible factor and also a difficult issue to be solved priorly. Especially, when both X and Y axes are simultaneously operating to accomplish complex tasks efficiently, additional coupling effects will be generated by the dynamic load presented on the crossbeam, which makes the synchronization issue more complicated than the case with static load. However, due to the absence of an accurate model to fully reveal the complete coupling characteristics, existing approaches to this issue still have inherent limitations. Therefore, this paper focuses on the systematic physical modeling and synchronization control of a DLMD gantry with a dynamic load presented on the crossbeam. A complete coupling mathematical model is established first, by fully considering two linear motions (X-axis and Y-axis) and also including the additional rotational motion of the crossbeam. Built upon the effective model information, corresponding solutions by compensating the dynamic load effects and actively controlling the rotational dynamics to regulate the internal forces have been proposed, leading to a novel adaptive robust synchronization control method. The results of comparative experiments verify the effectiveness and superiority of the proposed method in dealing with the synchronization issue subjected to dynamic load effects.

Study and modelling of droop-controlled islanded mesh microgrids

The active and reactive power sharing of distributed generation sources (DGs) connected to isolated microgrids with a single point of common coupling (mono-PCC) to which the loads are also connected has already been the subject of several studies. A high penetration rate of DGs based on renewable energies has as a logical consequence the development and implementation of mesh and more complex multi- PCC microgrids. In this paper, a developed droop control method for synchronization and power sharing between different DGs connected to a mesh islanded multi-PCC microgrid with many distributed generation sources (DGs) and different type of loads (including active load (CPL)) randomly connected to different PCCs is applied. Then, a state model of the entire mesh microgrid is developed integrating the generators with their controllers, power lines, droop algorithms and dynamic loads. This model is then used to study the asymptotic stability and robustness properties of the system. The simulation results confirm the effectiveness of the applied strategies for the synchronization of the different DGs to the microgrid while ensuring an efficient active and reactive power sharing. also, they confirm the validity of the developed state space model of the system.

Synthetic Adaptive Fuzzy Disturbance Observer and Sliding-Mode Control for Chaos-Based Secure Communication Systems

This paper aims to present secure communication based on master and slave Lorenz chaotic systems. To apply a form of the linear synchronization control method, the mathematical models of master and slave systems were reformed into Takagi-Sugeno (T-S) fuzzy systems. First, the Lorenz chaotic system was completely changed to the form of the T-S fuzzy model with two sublinear systems and two boundary fuzzy membership functions. Second, a newly adaptive disturbance observer (ADOB) was proposed with a high convergent speed for the synchronization system, which was based on the basic nonlinear disturbance observer. Third, adaptive sliding-mode control (ASMC) has been constructed to synchronize the master and slave systems of a secure communication system. The stability of the proposed control algorithms was shown by solving the Lyapunov condition with the support of Young's inequality. The synchronization of two nonidentical chaotic Lorenz systems was utilized to encrypt and decrypt the data. Transmitted and decrypted signals are used to show that the proposed algorithms are adequate for the secure communication system. To confirm the originality and power of the proposed algorithms, secure communication between two computers was implemented perfectly through an internet router and electronic circuit communication scenarios.

New Adaptive Control Strategy for a Wind Turbine Permanent Magnet Synchronous Generator (PMSG)

Wind energy conversion systems have become a key technology to harvest wind energy worldwide. In permanent magnet synchronous generator-based wind turbine systems, the rotor position is needed for variable speed control and it uses an encoder or a speed sensor. However, these sensors lead to some obstacles, such as additional weight and cost, increased noise, complexity and reliability issues. For these reasons, the development of new sensorless control methods has become critically important for wind turbine generators. This paper aims to develop a new sensorless and adaptive control method for a surface-mounted permanent magnet synchronous generator. The proposed method includes a new model reference adaptive system, which is used to estimate the rotor position and speed as an observer. Adaptive control is implemented in the pulse-width modulated current source converter. In the conventional model reference adaptive system, the proportional-integral controller is used in the adaptation mechanism. Moreover, the proportional-integral controller is generally tuned by the trial and error method, which is tedious and inaccurate. In contrast, the proposed method is based on model predictive control which eliminates the use of speed and position sensors and also improves the performance of model reference adaptive control systems. In this paper, the proposed predictive controller is modelled in MATLAB/SIMULINK and validated experimentally on a 6-kW wind turbine generator. Test results prove the effectiveness of the control strategy in terms of energy efficiency and dynamical adaptation to the wind turbine operational conditions. The experimental results also show that the control method has good dynamic response to parameter variations and external disturbances. Therefore, the developed technique will help increase the uptake of permanent magnet synchronous generators and model predictive control methods in the wind power industry.

Evaluating the effectiveness of several synchronization control methods applying to the electrically and the chemically coupled hindmarsh-rose neurons

This study focuses on the synchronization control between the coupled neurons. The achievements of several synchronization control methods have been checked by evaluating the effects of the synaptic coupling weight alteration on the synchronization. Here, a neural ensemble has been constructed by utilizing the Hindmarsh Rose (HR) Neuron Model. The HR neurons have been linked to each other with the bidirectional coupling. The synchrony or the asynchrony states between these coupled neurons have been observed by using the standard deviation results. Here, firstly, the electrically and the chemically coupled HR neurons have been handled without using any control method, separately and the effects of the synaptic coupling weight alteration on the synchronic firing have been assessed by considering the features of the coupling types. Then, while the electrically coupled HR neurons are generally preferred in the available synchronization control studies; the Lyapunov, the back-stepping, and the feedback synchronization control methods have been adapted to both the electrically and the chemically coupled HR neurons. Thus, a remarkable contribution has been provided to the limited number of studies, which are about the synchronization control of the chemically coupled HR neurons. Also, the synchronization control between the electrically or the chemically coupled HR neurons has been provided by the back-stepping method for the first time. Finally, the differences between the membrane potentials of the coupled neurons have been calculated by utilizing an alternative error function. Since this function calculates the amplitude and the phase errors, separately; the effectiveness of these methods can be evaluated correctly in terms of the performing the minimum differences between the neural dynamics.

Carbon dioxide emission in a single-lane cellular automaton model with a series of traffic lights

In this paper, we propose a cellular automaton model to simulate traffic flow controlled by a series of traffic lights. The synchronized traffic light and the green wave light strategies were investigated. The spatiotemporal diagrams, energy dissipation, and CO2 emission of the system were presented. Our simulations are conducted to clarify the difference between both strategies and their effects on the traffic flow and the CO2 emission. We found that the traffic flow depends mainly on the strategy used for managing the traffic lights as well as on the parameters of the traffic lights, namely the cycle length, the number of traffic lights and the length of the system. The fundamental diagram has barely the same characteristics for both methods and it depends on the combination of the parameters of the system. We find that the green wave is more convenient for the management of a series of traffic lights than the synchronized control strategy in terms of throughput, especially for large-sized systems. Unlike in terms of CO2 emission and energy dissipation, both control strategies outperform each other depending on the density regions and the parameters of the system. Finally, we investigate the effect of both cycles (i.e. red and green) for the synchronized control method on the CO2 emission. It is found that the green cycle generates often a series of acceleration events that increase CO2 emission.

Full state constraints control of switched complex networks based on time‐varying barrier Lyapunov functions

This manuscript proposes an adaptive backstepping synchronous control method with full state constraints by drawing into the time-varying barrier Lyapunov functions (T-BLFs) for a kind of uncertain switched complex networks. Generally, a complex dynamic network in practical terms either possesses a switched topology or its nodes are with switched parameters. In this context, the synchronisation problem of the switched complex network is tackled by utilising adaptive backstepping method after converting switched complex network into the non-autonomous strict feedback form. Meanwhile, most of the system states are supposed to be constrained during the switch over the procedure. Thus, the constraint-handling method based on T-BLFs is developed in the backstepping process to guarantee the full state restriction boundaries are not violated, and then to realise the asymptotic stability of the nodes states of the switched complex networks. Four simulation examples are presented to verify the feasibility and effectiveness of the proposed control approach.

Optimal design and experiment of 2-DoF five-bar mechanism for flower seedling transplanting

The currently used large-scale flower seedling transplanting equipment is expensive and has poor adaptability, while the small-scale transplanting equipment has problems with seedling damage and low automation. In view of this situation, a 2-DoF five-bar transplanting mechanism for multiple-point picking to single-point planting was designed. In a motion cycle, the seedlings could be picked from the four holes of a seedling disc and then planted in the flowerpot at a given point through the motion control of actuators, where the coordination among the transplanting, flowerpot transporting, and seedling delivering in the developed system was simplified. For seedling picking, the end-effector inserted into the substrate near the root of the seedling stem for damage avoidance, the transplanting trajectory was designed based on the given trajectory-type waypoints that satisfies the requirements of flower seedling transplanting. Besides, the mathematical model was established, where the relationship of the motion between the parameters of the developed 2-DoF five-bar transplanting mechanism and the two actuators were optimized by the genetic algorithm. Finally, the corresponding control system was designed, the two actuators were driven by two servo motors, and the end-effector was controlled by an electromagnet in the transplanting arm to realize the seedling clamping and releasing motion. In addition, a dual servo motor synchronous linkage control method was established based on the DDA linear interpolation algorithm to reduce the deviation of the servo motors, the linkage control of the electromagnet and the motor was realized through a single-chip microprocessor to achieve the coordination of the actuators. The overall design was deployed in real transplanting working conditions for validation, where several 30-day broccoli seedlings were used as experimental objects. The seedling height was around 80–100 mm and the transplanting rate was 40 plants/min. Three sets of seedlings (384 seedlings in total) were transplanted with an average transplanting success rate of 91.81%.

Design of Dual-Drive Vertical Lift Servo System and Synchronous Control Performance Analysis

This article introduces a new dual-drive vertical lift servo system with a slipway that can be used to help people or other intelligent equipment complete high-altitude work better on the exterior wall of the high-rise buildings. In order to improve the system motion performance, enhance the robustness against the variation of system parameters and external disturbances, and minimize position error, a control scheme that integrates proportional-integral-derivative (PID) control and fast terminal sliding-mode control (FTSMC) is applied. The combination of the characteristics of both the PID and FTSMC ensures that the vertical lift servo system achieves motion stability, rapid convergence with small steady-state errors, and strong robustness against variation parameters and external disturbances. Potential rotational dynamics around the center of mass and synchronous error that mainly results from varying loads are reduced through the proposed control torque allocation scheme. The performance of the control scheme is investigated through extensive simulations. Moreover, a series of experimental studies demonstrate the effectiveness of the proposed synchronous position control method for the vertical lift system actuated by the two parallel servo drive systems.