This paper researches the time-varying formation tracking (TVFT) problem of linear multi-agent systems (MASs). By designing a compensator, the problem of time-varying formation can be considered as the output regulation problem. Thereby, the distributed output feedback controller combined with an adaptive technique is proposed. With this controller, follower agents achieve the desired time-varying formation and follow the trajectory of the leader agent. Furthermore, extending the designed controller to the case where the leader agent equips with unknown control input. Using Lyapunov stability theory, it is demonstrated that under proper conditions the given protocol is implementable. Simulation example is presented at the end of the paper to illustrate the effectiveness of designed control mechanism.
{"title":"Adaptive output feedback time-varying formation tracking of multi-agent system with a leader of unknown input","authors":"Jie Wu, Xiaoyi Zhang, Xisheng Zhan, Xiushan Cai","doi":"10.1002/asjc.3499","DOIUrl":"https://doi.org/10.1002/asjc.3499","url":null,"abstract":"This paper researches the time-varying formation tracking (TVFT) problem of linear multi-agent systems (MASs). By designing a compensator, the problem of time-varying formation can be considered as the output regulation problem. Thereby, the distributed output feedback controller combined with an adaptive technique is proposed. With this controller, follower agents achieve the desired time-varying formation and follow the trajectory of the leader agent. Furthermore, extending the designed controller to the case where the leader agent equips with unknown control input. Using Lyapunov stability theory, it is demonstrated that under proper conditions the given protocol is implementable. Simulation example is presented at the end of the paper to illustrate the effectiveness of designed control mechanism.","PeriodicalId":55453,"journal":{"name":"Asian Journal of Control","volume":"1 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142249512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper considers a rotating Euler-Bernoulli beam system with no dampings, where disturbances and references are generated from a block diagonalizable exosystem. Two tracking errors are the only measurable outputs for the output regulation of the beam system. Firstly, a nominal exosystem is chosen to generate the same signals, and a nominal beam is obtained by finding the specially known coefficients of the disturbances and references. This makes a tracking error-based observer easily designed for the nominal partial differential equation-ordinary differential equation (PDE-ODE) system. Observer-based robust controls are then designed for the nominal beam system and further proved to guarantee the asymptotic convergence of the tracking errors and the boundedness of the states, although under unknown disturbances and references. Two simulation examples are provided to describe the effectiveness of the controls.
{"title":"Observer-based output feedback control for a rotating beam with a general exosystem","authors":"Tingting Meng, Qiang Fu, Xiuyu He","doi":"10.1002/asjc.3483","DOIUrl":"https://doi.org/10.1002/asjc.3483","url":null,"abstract":"This paper considers a rotating Euler-Bernoulli beam system with no dampings, where disturbances and references are generated from a block diagonalizable exosystem. Two tracking errors are the only measurable outputs for the output regulation of the beam system. Firstly, a nominal exosystem is chosen to generate the same signals, and a nominal beam is obtained by finding the specially known coefficients of the disturbances and references. This makes a tracking error-based observer easily designed for the nominal partial differential equation-ordinary differential equation (PDE-ODE) system. Observer-based robust controls are then designed for the nominal beam system and further proved to guarantee the asymptotic convergence of the tracking errors and the boundedness of the states, although under unknown disturbances and references. Two simulation examples are provided to describe the effectiveness of the controls.","PeriodicalId":55453,"journal":{"name":"Asian Journal of Control","volume":"186 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142249513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we explore the utilization of machine learning techniques for solving the numerical solutions of continuous-time differential Riccati equations. Specifically, we focus on generating a reduction matrix capable of transforming a high-order matrix into a low-order matrix. Additionally, we address the issue of differential terms in the continuous-time differential Riccati equation and incorporate the backward differentiation formula of the matrix to improve stability and accuracy. Finally, by training samples through neural networks and machine learning methods, we could predict the solutions for high-order matrix equations.
{"title":"Backward differentiation formula method and random forest method to solve continuous-time differential Riccati equations","authors":"Juan Zhang, Wenwen Zou, Chenglin Sui","doi":"10.1002/asjc.3494","DOIUrl":"https://doi.org/10.1002/asjc.3494","url":null,"abstract":"In this paper, we explore the utilization of machine learning techniques for solving the numerical solutions of continuous-time differential Riccati equations. Specifically, we focus on generating a reduction matrix capable of transforming a high-order matrix into a low-order matrix. Additionally, we address the issue of differential terms in the continuous-time differential Riccati equation and incorporate the backward differentiation formula of the matrix to improve stability and accuracy. Finally, by training samples through neural networks and machine learning methods, we could predict the solutions for high-order matrix equations.","PeriodicalId":55453,"journal":{"name":"Asian Journal of Control","volume":"27 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142249514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper is concerned with the optimal quantized feedback linear quadratic Gaussian (LQG) control problem for a discrete-time stochastic system with input delay as well as the measurements to be quantized before transmitted to the controller. In this scenario, the system is presented with several choices of quantizers, along with the cost of using each quantizer. The objective is to jointly select the quantizers and synthesize the controller to maintain an optimal balance between control performance and quantization cost. It is shown that this problem can be decoupled into two optimization problems when the innovation signal is quantized instead of state: one for optimal controller synthesis and the other for optimal quantizer selection. More specifically, a necessary and sufficient condition is derived for the optimal control problem based on Pontryagin's maximum principle. On the other hand, the optimal quantizer selection policy is established by dealing with a certain Markov decision process (MDP).
{"title":"Optimal quantized feedback control for linear quandratic Gaussian systems with input delay","authors":"Huiling Chen, Xiao liang, Guilin Zhang","doi":"10.1002/asjc.3493","DOIUrl":"https://doi.org/10.1002/asjc.3493","url":null,"abstract":"This paper is concerned with the optimal quantized feedback linear quadratic Gaussian (LQG) control problem for a discrete-time stochastic system with input delay as well as the measurements to be quantized before transmitted to the controller. In this scenario, the system is presented with several choices of quantizers, along with the cost of using each quantizer. The objective is to jointly select the quantizers and synthesize the controller to maintain an optimal balance between control performance and quantization cost. It is shown that this problem can be decoupled into two optimization problems when the innovation signal is quantized instead of state: one for optimal controller synthesis and the other for optimal quantizer selection. More specifically, a necessary and sufficient condition is derived for the optimal control problem based on Pontryagin's maximum principle. On the other hand, the optimal quantizer selection policy is established by dealing with a certain Markov decision process (MDP).","PeriodicalId":55453,"journal":{"name":"Asian Journal of Control","volume":"3 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142249516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xinsheng Wang, Bin Jiang, Tong Yao, Huaqiang Zhang
This paper introduces a robust position tracking control structure of exoskeleton robots (ERs). An open environment and body flexibility are the main challenges in ER control system design. First, a fractional-order nonsingular terminal sliding mode (FONTSM) controller is proposed for a robotic manipulator with uncertainty, where lumped unknown dynamics are computed by time-delay estimation (TDE). Secondly, a robust exact differentiator (RED) is employed as the output feedback observer for the velocity sensorless robotic system. Thirdly, the stability of the FONTSM control system is demonstrated. It is proved that the system error can move to the specified value along the sliding mode surface at a fixed time and can reach the sliding mode surface after a finite time. Finally, simulations on a 2-DOF robotic manipulator show the effectiveness of the fixed-time control strategies. When a combined trigonometric function disturbance is applied, the joint angle error is reduced to 1% by the model-free controller based on output feedback within approximately 1 s.
{"title":"Fractional-order fixed-time sliding mode control of robotic manipulators with robust exact differentiator","authors":"Xinsheng Wang, Bin Jiang, Tong Yao, Huaqiang Zhang","doi":"10.1002/asjc.3484","DOIUrl":"https://doi.org/10.1002/asjc.3484","url":null,"abstract":"This paper introduces a robust position tracking control structure of exoskeleton robots (ERs). An open environment and body flexibility are the main challenges in ER control system design. First, a fractional-order nonsingular terminal sliding mode (FONTSM) controller is proposed for a robotic manipulator with uncertainty, where lumped unknown dynamics are computed by time-delay estimation (TDE). Secondly, a robust exact differentiator (RED) is employed as the output feedback observer for the velocity sensorless robotic system. Thirdly, the stability of the FONTSM control system is demonstrated. It is proved that the system error can move to the specified value along the sliding mode surface at a fixed time and can reach the sliding mode surface after a finite time. Finally, simulations on a 2-DOF robotic manipulator show the effectiveness of the fixed-time control strategies. When a combined trigonometric function disturbance is applied, the joint angle error is reduced to 1% by the model-free controller based on output feedback within approximately 1 s.","PeriodicalId":55453,"journal":{"name":"Asian Journal of Control","volume":"14 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142249515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article proposes a novel modified fixed‐time synergetic control (MFTSC) approach to address the quadrotor control problem in the presence of external disturbances. In contrast to previous fixed‐time synergetic control (FTSC) methods, the proposed approach employs an aggregate macrovariable expression with independent fractional powers. This expression expands the set of real numbers that the parameters of the fractional power can take, leading to a significantly higher rate of convergence toward optimal control parameters (more than 28‐fold), as demonstrated through geometric analysis. The stability of the proposed control system is established, and numerical simulations and experimental validation are conducted using a quadrotor test bench to corroborate the theoretical results.
{"title":"Quadrotor attitude control with a modified fixed‐time synergetic controller: A geometric analysis and experimental validation","authors":"Saadi Achour, Khalil Mokhtari, Abdelaziz Rahmoune","doi":"10.1002/asjc.3498","DOIUrl":"https://doi.org/10.1002/asjc.3498","url":null,"abstract":"This article proposes a novel modified fixed‐time synergetic control (MFTSC) approach to address the quadrotor control problem in the presence of external disturbances. In contrast to previous fixed‐time synergetic control (FTSC) methods, the proposed approach employs an aggregate macrovariable expression with independent fractional powers. This expression expands the set of real numbers that the parameters of the fractional power can take, leading to a significantly higher rate of convergence toward optimal control parameters (more than 28‐fold), as demonstrated through geometric analysis. The stability of the proposed control system is established, and numerical simulations and experimental validation are conducted using a quadrotor test bench to corroborate the theoretical results.","PeriodicalId":55453,"journal":{"name":"Asian Journal of Control","volume":"23 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142249517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Control constraints are common in real‐world applications. However, when the control constraint depends on the system state, designing a stabilizing output feedback that adheres to the constraint can be challenging if the state is unmeasurable. This study proposes a novel dual‐loop structural output feedback for logical dynamical systems (LDSs) with state‐dependent control constraints. The inner‐loop controller is a pre‐output feedback designed based on the state‐dependent constraint, which always selects a common admissible control for all possible states. A system with free control input is obtained by combining the pre‐output feedback with the LDS. The outer‐loop controller, an ordinary output feedback, is then designed for the combined system. It is proven that any admissible time‐invariant output feedback can be decomposed into a pre‐output feedback and an ordinary output feedback. Furthermore, a necessary and sufficient condition for stabilizability by admissible output feedback is obtained. Finally, an example is presented to demonstrate the effectiveness of the obtained results.
{"title":"Output feedback stabilization of logical dynamical systems with state‐dependent control constraints","authors":"Chaoqun Dai, Yuqian Guo","doi":"10.1002/asjc.3495","DOIUrl":"https://doi.org/10.1002/asjc.3495","url":null,"abstract":"Control constraints are common in real‐world applications. However, when the control constraint depends on the system state, designing a stabilizing output feedback that adheres to the constraint can be challenging if the state is unmeasurable. This study proposes a novel dual‐loop structural output feedback for logical dynamical systems (LDSs) with state‐dependent control constraints. The inner‐loop controller is a pre‐output feedback designed based on the state‐dependent constraint, which always selects a common admissible control for all possible states. A system with free control input is obtained by combining the pre‐output feedback with the LDS. The outer‐loop controller, an ordinary output feedback, is then designed for the combined system. It is proven that any admissible time‐invariant output feedback can be decomposed into a pre‐output feedback and an ordinary output feedback. Furthermore, a necessary and sufficient condition for stabilizability by admissible output feedback is obtained. Finally, an example is presented to demonstrate the effectiveness of the obtained results.","PeriodicalId":55453,"journal":{"name":"Asian Journal of Control","volume":"2 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142249518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the design of an adaptive backstepping (BS) nonlinear controller for time‐varying disturbances in flight control. The discrete Fourier transform (DFT) is used to design an adaptive law to suppress the influence of time‐varying disturbances. The traditional adaptive BS method ignores the derivatives of disturbances in the deduction process and cannot address certain fast, time‐varying disturbances well. Therefore, an improved adaptive BS method based on the DFT is proposed. Instead of estimating the disturbance directly, the proposed method obtains the time‐domain expression of the disturbance indirectly by estimating the disturbance spectrum and performing inverse DFT. The proposed method effectively overcomes the inability of the traditional adaptive BS method to estimate fast, time‐varying disturbances accurately. Finally, the proposed method is compared with traditional adaptive BS and radial basis function (RBF) neural network control methods. Simulation results confirm that the proposed method outperforms other methods under Gaussian disturbance and turbulence.
{"title":"Disturbance estimation backstepping flight control based on the discrete Fourier transform","authors":"Ruichen Ming, Xiaoxiong Liu, Yu Li, Weiguo Zhang","doi":"10.1002/asjc.3491","DOIUrl":"https://doi.org/10.1002/asjc.3491","url":null,"abstract":"This paper presents the design of an adaptive backstepping (BS) nonlinear controller for time‐varying disturbances in flight control. The discrete Fourier transform (DFT) is used to design an adaptive law to suppress the influence of time‐varying disturbances. The traditional adaptive BS method ignores the derivatives of disturbances in the deduction process and cannot address certain fast, time‐varying disturbances well. Therefore, an improved adaptive BS method based on the DFT is proposed. Instead of estimating the disturbance directly, the proposed method obtains the time‐domain expression of the disturbance indirectly by estimating the disturbance spectrum and performing inverse DFT. The proposed method effectively overcomes the inability of the traditional adaptive BS method to estimate fast, time‐varying disturbances accurately. Finally, the proposed method is compared with traditional adaptive BS and radial basis function (RBF) neural network control methods. Simulation results confirm that the proposed method outperforms other methods under Gaussian disturbance and turbulence.","PeriodicalId":55453,"journal":{"name":"Asian Journal of Control","volume":"58 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the gradual deregulation of the power system by the power department, the power system has developed into a large‐scale and multiregional control system. Because of the power system internal complexity enhancing, the stable operation of power system becomes increasingly difficult. This paper analyzes the load frequency control problem of multiregional interconnected power system with wind energy. This study designs an improved model‐free adaptive control algorithm based on I/O data. It avoids model establishment of the multiregional power system. It also effectively solves the problem of frequency stability control under the influence of load change, introducing the generation participation matrix to simulate bilateral contracts under the power market. The dynamic evolution relationship of the system with the generation participation matrix is established, taking a three‐regional power system with wind energy as an example. Frequency fluctuations in all three regions are between . Convergence times of frequency deviation are all within 30 s, much less than the response time of load frequency control. The simulation results further demonstrate the effectiveness of the proposed algorithm, comparing the control algorithm proposed in this paper with other algorithms, which proves that the proposed algorithm has good control performance.
{"title":"Model‐free adaptive load frequency control for power systems with wind penetration under deregulation environment","authors":"Yiming Zeng, Xuhui Bu, Yanling Yin","doi":"10.1002/asjc.3481","DOIUrl":"https://doi.org/10.1002/asjc.3481","url":null,"abstract":"With the gradual deregulation of the power system by the power department, the power system has developed into a large‐scale and multiregional control system. Because of the power system internal complexity enhancing, the stable operation of power system becomes increasingly difficult. This paper analyzes the load frequency control problem of multiregional interconnected power system with wind energy. This study designs an improved model‐free adaptive control algorithm based on I/O data. It avoids model establishment of the multiregional power system. It also effectively solves the problem of frequency stability control under the influence of load change, introducing the generation participation matrix to simulate bilateral contracts under the power market. The dynamic evolution relationship of the system with the generation participation matrix is established, taking a three‐regional power system with wind energy as an example. Frequency fluctuations in all three regions are between . Convergence times of frequency deviation are all within 30 s, much less than the response time of load frequency control. The simulation results further demonstrate the effectiveness of the proposed algorithm, comparing the control algorithm proposed in this paper with other algorithms, which proves that the proposed algorithm has good control performance.","PeriodicalId":55453,"journal":{"name":"Asian Journal of Control","volume":"36 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper addresses the issue of fault estimation in nonlinear multi‐agent systems characterized by a leader–follower structure within directed graphs. The proposed approach begins by developing a distributed fault observer that utilizes relative output estimation error. Subsequently, a dynamic error system is constructed to convert the fault estimation problem into a stability problem for the dynamic error system. Finally, the conditions for achieving asymptotic boundedness of the dynamic error system are presented in the form of linear matrix inequalities. Simulation results substantiate the efficacy of the proposed method, revealing the ability of the distributed fault observer to accurately estimate faults occurring in multiple followers of the multi‐agent system.
{"title":"Distributed fault estimation observer design for nonlinear multi‐agent systems with directed graphs","authors":"Yuhui Weng, Jianwei Liu, Huiwen Liu, Ruizhi Qin","doi":"10.1002/asjc.3485","DOIUrl":"https://doi.org/10.1002/asjc.3485","url":null,"abstract":"This paper addresses the issue of fault estimation in nonlinear multi‐agent systems characterized by a leader–follower structure within directed graphs. The proposed approach begins by developing a distributed fault observer that utilizes relative output estimation error. Subsequently, a dynamic error system is constructed to convert the fault estimation problem into a stability problem for the dynamic error system. Finally, the conditions for achieving asymptotic boundedness of the dynamic error system are presented in the form of linear matrix inequalities. Simulation results substantiate the efficacy of the proposed method, revealing the ability of the distributed fault observer to accurately estimate faults occurring in multiple followers of the multi‐agent system.","PeriodicalId":55453,"journal":{"name":"Asian Journal of Control","volume":"8 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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