Norm optimal iterative learning control(NOILC) has recently been applied to iterative learning control(ILC) problems in which tracking is only required at a subset of isolated time points along the trial duration. Thi...Norm optimal iterative learning control(NOILC) has recently been applied to iterative learning control(ILC) problems in which tracking is only required at a subset of isolated time points along the trial duration. This problem addresses the practical needs of many applications, including industrial automation, crane control, satellite positioning and motion control within a medical stroke rehabilitation context. This paper provides a substantial generalization of this framework by providing a solution to the problem of convergence at intermediate points with simultaneous tracking of subsets of outputs to reference trajectories on subintervals. This formulation enables the NOILC paradigm to tackle tasks which mix "point to point" movements with linear tracking requirements and hence substantially broadens the application domain to include automation tasks which include welding or cutting movements, or human motion control where the movement is restricted by the task to straight line and/or planar segments. A solution to the problem is presented in the framework of NOILC and inherits NOILC s well-defined convergence properties. Design guidelines and supporting experimental results are included.展开更多
This paper analyses the concept of a Limit Set in Parameter Optimal Iterative Learning Control （ILC）. We investigate the existence of stable and unstable parts of Limit Set and demonstrates that they will often exis...This paper analyses the concept of a Limit Set in Parameter Optimal Iterative Learning Control （ILC）. We investigate the existence of stable and unstable parts of Limit Set and demonstrates that they will often exist in practice. This is illustrated via a 2-dimensional example where the convergence of the learning algorithm is analyzed from the error＇s dynamic behaviour. These ideas are extended to the N-dimensional cases by analogy and example.展开更多
In this paper, a quasi-Newton-type optimized iterative learning control （ILC） algorithm is investigated for a class of discrete linear time-invariant systems. The proposed learning algorithm is to update the learnin...In this paper, a quasi-Newton-type optimized iterative learning control （ILC） algorithm is investigated for a class of discrete linear time-invariant systems. The proposed learning algorithm is to update the learning gain matrix by a quasi-Newton-type matrix instead of the inversion of the plant. By means of the mathematical inductive method, the monotone convergence of the proposed algorithm is analyzed, which shows that the tracking error monotonously converges to zero after a finite number of iterations. Compared with the existing optimized ILC algorithms, due to the superlinear convergence of quasi-Newton method, the proposed learning law operates with a faster convergent rate and is robust to the ill-condition of the system model, and thus owns a wide range of applications. Numerical simulations demonstrate the validity and effectiveness.展开更多
In the procedure of the steady-state hierarchical optimization with feedback for large-scale industrial processes, a sequence of set-point changes with different magnitudes is carried out on the optimization layer. To...In the procedure of the steady-state hierarchical optimization with feedback for large-scale industrial processes, a sequence of set-point changes with different magnitudes is carried out on the optimization layer. To improve the dynamic performance of transient response driven by the set-point changes, a filter-based iterative learning control strategy is proposed. In the proposed updating law, a local-symmetric-integral operator is adopted for eliminating the measurement noise of output information,a set of desired trajectories are specified according to the set-point changes sequence, the current control input is iteratively achieved by utilizing smoothed output error to modify its control input at previous iteration, to which the amplified coefficients related to the different magnitudes of set-point changes are introduced. The convergence of the algorithm is conducted by incorporating frequency-domain technique into time-domain analysis. Numerical simulation demonstrates the effectiveness of the proposed strategy,展开更多
The goal of this paper is to design a model-free optimal controller for the multirate system based on reinforcement learning.Sampled-data control systems are widely used in the industrial production process and multir...The goal of this paper is to design a model-free optimal controller for the multirate system based on reinforcement learning.Sampled-data control systems are widely used in the industrial production process and multirate sampling has attracted much attention in the study of the sampled-data control theory.In this paper,we assume the sampling periods for state variables are different from periods for system inputs.Under this condition,we can obtain an equivalent discrete-time system using the lifting technique.Then,we provide an algorithm to solve the linear quadratic regulator(LQR)control problem of multirate systems with the utilization of matrix substitutions.Based on a reinforcement learning method,we use online policy iteration and off-policy algorithms to optimize the controller for multirate systems.By using the least squares method,we convert the off-policy algorithm into a model-free reinforcement learning algorithm,which only requires the input and output data of the system.Finally,we use an example to illustrate the applicability and efficiency of the model-free algorithm above mentioned.展开更多
In the stability framework of model predictive control(MPC),the size of the stabilizable set(also known as the region of attraction)is dependent on the terminal constraint region.This article aims to investigate the o...In the stability framework of model predictive control(MPC),the size of the stabilizable set(also known as the region of attraction)is dependent on the terminal constraint region.This article aims to investigate the optimization of the terminal region for predictive control of a class of systems with multiplicative uncertainty,aiming to expand the attraction region in MPC.By utilizing a coordinate transformation,we initially develop a structured design for terminal ingredients while considering uncertainties in parameters.Subsequently,we propose novel methods to convert the original nonlinear problem into a linear matrix inequality(LMI)problem with minimal conservatism in the formulation.We propose an iterative learning optimization approach to compute the polytopic terminal region,and its incremental volume is theoretically proven.The efectiveness of the proposed approaches is demonstrated using a benchmark academic example and vehicle lateral dynamics.Through real-time simulation experiments,we demonstrate that the proposed approach can enlarge the domain of attraction as well as reduce the computational complexity of robust MPC systems under parameter uncertainty.展开更多
This paper presents several neural network based modelling, reliable optimal control, and iterative learning control methods for batch processes. In order to overcome the lack of robustness of a single neural network,...This paper presents several neural network based modelling, reliable optimal control, and iterative learning control methods for batch processes. In order to overcome the lack of robustness of a single neural network, bootstrap aggregated neural networks are used to build reliable data based empirical models. Apart from improving the model generalisation capability, a bootstrap aggregated neural network can also provide model prediction confidence bounds. A reliable optimal control method by incorporating model prediction confidence bounds into the optimisation objective function is presented. A neural network based iterative learning control strategy is presented to overcome the problem due to unknown disturbances and model-plant mismatches. The proposed methods are demonstrated on a simulated batch polymerisation process.展开更多
Batch processes have been increasingly used in the production of low volume and high value added products. Consequently, optimization control in batch processes is crucial in order to derive the maximum benefit. In th...Batch processes have been increasingly used in the production of low volume and high value added products. Consequently, optimization control in batch processes is crucial in order to derive the maximum benefit. In this paper, a run-to-run product quality control based on iterative learning optimization control is developed. Moreover, a rigorous theorem is proposed and proven in this paper, which states that the tracking error under the optimal iterative learning control （ILC） law can converge to zero. In this paper, a typical nonlinear batch continuous stirred tank reactor （CSTR） is considered, and the results show that the performance of trajectory tracking is gradually improved by the ILC.展开更多
This paper presents a novel optimal synchronization control method for multi-agent systems with input saturation.The multi-agent game theory is introduced to transform the optimal synchronization control problem into ...This paper presents a novel optimal synchronization control method for multi-agent systems with input saturation.The multi-agent game theory is introduced to transform the optimal synchronization control problem into a multi-agent nonzero-sum game.Then,the Nash equilibrium can be achieved by solving the coupled Hamilton–Jacobi–Bellman(HJB)equations with nonquadratic input energy terms.A novel off-policy reinforcement learning method is presented to obtain the Nash equilibrium solution without the system models,and the critic neural networks(NNs)and actor NNs are introduced to implement the presented method.Theoretical analysis is provided,which shows that the iterative control laws converge to the Nash equilibrium.Simulation results show the good performance of the presented method.展开更多
文摘Norm optimal iterative learning control(NOILC) has recently been applied to iterative learning control(ILC) problems in which tracking is only required at a subset of isolated time points along the trial duration. This problem addresses the practical needs of many applications, including industrial automation, crane control, satellite positioning and motion control within a medical stroke rehabilitation context. This paper provides a substantial generalization of this framework by providing a solution to the problem of convergence at intermediate points with simultaneous tracking of subsets of outputs to reference trajectories on subintervals. This formulation enables the NOILC paradigm to tackle tasks which mix "point to point" movements with linear tracking requirements and hence substantially broadens the application domain to include automation tasks which include welding or cutting movements, or human motion control where the movement is restricted by the task to straight line and/or planar segments. A solution to the problem is presented in the framework of NOILC and inherits NOILC s well-defined convergence properties. Design guidelines and supporting experimental results are included.
文摘This paper analyses the concept of a Limit Set in Parameter Optimal Iterative Learning Control （ILC）. We investigate the existence of stable and unstable parts of Limit Set and demonstrates that they will often exist in practice. This is illustrated via a 2-dimensional example where the convergence of the learning algorithm is analyzed from the error＇s dynamic behaviour. These ideas are extended to the N-dimensional cases by analogy and example.
基金supported by the National Natural Science Foundation of China(Nos.F010114-60974140,61273135)
文摘In this paper, a quasi-Newton-type optimized iterative learning control （ILC） algorithm is investigated for a class of discrete linear time-invariant systems. The proposed learning algorithm is to update the learning gain matrix by a quasi-Newton-type matrix instead of the inversion of the plant. By means of the mathematical inductive method, the monotone convergence of the proposed algorithm is analyzed, which shows that the tracking error monotonously converges to zero after a finite number of iterations. Compared with the existing optimized ILC algorithms, due to the superlinear convergence of quasi-Newton method, the proposed learning law operates with a faster convergent rate and is robust to the ill-condition of the system model, and thus owns a wide range of applications. Numerical simulations demonstrate the validity and effectiveness.
基金This work was supported by the National Natural Science Foundation of China (No. 60274055)
文摘In the procedure of the steady-state hierarchical optimization with feedback for large-scale industrial processes, a sequence of set-point changes with different magnitudes is carried out on the optimization layer. To improve the dynamic performance of transient response driven by the set-point changes, a filter-based iterative learning control strategy is proposed. In the proposed updating law, a local-symmetric-integral operator is adopted for eliminating the measurement noise of output information,a set of desired trajectories are specified according to the set-point changes sequence, the current control input is iteratively achieved by utilizing smoothed output error to modify its control input at previous iteration, to which the amplified coefficients related to the different magnitudes of set-point changes are introduced. The convergence of the algorithm is conducted by incorporating frequency-domain technique into time-domain analysis. Numerical simulation demonstrates the effectiveness of the proposed strategy,
基金Supported by National Natural Science Foundation of China （F030101-60574021） and National ＂985＂ Project of China Executed in Xi＇an Jiaotong University
基金This work was supported by National Key R&D Program of China(No.2018YFB1308404).
文摘The goal of this paper is to design a model-free optimal controller for the multirate system based on reinforcement learning.Sampled-data control systems are widely used in the industrial production process and multirate sampling has attracted much attention in the study of the sampled-data control theory.In this paper,we assume the sampling periods for state variables are different from periods for system inputs.Under this condition,we can obtain an equivalent discrete-time system using the lifting technique.Then,we provide an algorithm to solve the linear quadratic regulator(LQR)control problem of multirate systems with the utilization of matrix substitutions.Based on a reinforcement learning method,we use online policy iteration and off-policy algorithms to optimize the controller for multirate systems.By using the least squares method,we convert the off-policy algorithm into a model-free reinforcement learning algorithm,which only requires the input and output data of the system.Finally,we use an example to illustrate the applicability and efficiency of the model-free algorithm above mentioned.
基金supported by the the Fundamental Research Funds for the Central Universities(Grant No.JUSRP202501133)。
文摘In the stability framework of model predictive control(MPC),the size of the stabilizable set(also known as the region of attraction)is dependent on the terminal constraint region.This article aims to investigate the optimization of the terminal region for predictive control of a class of systems with multiplicative uncertainty,aiming to expand the attraction region in MPC.By utilizing a coordinate transformation,we initially develop a structured design for terminal ingredients while considering uncertainties in parameters.Subsequently,we propose novel methods to convert the original nonlinear problem into a linear matrix inequality(LMI)problem with minimal conservatism in the formulation.We propose an iterative learning optimization approach to compute the polytopic terminal region,and its incremental volume is theoretically proven.The efectiveness of the proposed approaches is demonstrated using a benchmark academic example and vehicle lateral dynamics.Through real-time simulation experiments,we demonstrate that the proposed approach can enlarge the domain of attraction as well as reduce the computational complexity of robust MPC systems under parameter uncertainty.
基金Supported by UK EPSRC (grants GR/N13319 and GR/R 10875)
文摘This paper presents several neural network based modelling, reliable optimal control, and iterative learning control methods for batch processes. In order to overcome the lack of robustness of a single neural network, bootstrap aggregated neural networks are used to build reliable data based empirical models. Apart from improving the model generalisation capability, a bootstrap aggregated neural network can also provide model prediction confidence bounds. A reliable optimal control method by incorporating model prediction confidence bounds into the optimisation objective function is presented. A neural network based iterative learning control strategy is presented to overcome the problem due to unknown disturbances and model-plant mismatches. The proposed methods are demonstrated on a simulated batch polymerisation process.
基金supported by the Science Foundation of Shanghai Municipal Education Commission (Grant No.09Y208)the Science Foundation of Science and Technology Commission of Shanghai Municipality (Grant Nos.08DZ2272400, 09DZ2273400)the "11th Five-Year Plan" 211 Construction Project of Shanghai University
文摘Batch processes have been increasingly used in the production of low volume and high value added products. Consequently, optimization control in batch processes is crucial in order to derive the maximum benefit. In this paper, a run-to-run product quality control based on iterative learning optimization control is developed. Moreover, a rigorous theorem is proposed and proven in this paper, which states that the tracking error under the optimal iterative learning control （ILC） law can converge to zero. In this paper, a typical nonlinear batch continuous stirred tank reactor （CSTR） is considered, and the results show that the performance of trajectory tracking is gradually improved by the ILC.
基金Project supported by the National Key R&D Program of China(No.2018YFB1702300)the National Natural Science Foundation of China(Nos.61722312 and 61533017)。
文摘This paper presents a novel optimal synchronization control method for multi-agent systems with input saturation.The multi-agent game theory is introduced to transform the optimal synchronization control problem into a multi-agent nonzero-sum game.Then,the Nash equilibrium can be achieved by solving the coupled Hamilton–Jacobi–Bellman(HJB)equations with nonquadratic input energy terms.A novel off-policy reinforcement learning method is presented to obtain the Nash equilibrium solution without the system models,and the critic neural networks(NNs)and actor NNs are introduced to implement the presented method.Theoretical analysis is provided,which shows that the iterative control laws converge to the Nash equilibrium.Simulation results show the good performance of the presented method.
