Two types of iterative learning controllers for batch processes are presented in this paper. The controllers not only contain a feedforward term, but also incorporate a feedback term and a difference term. First, vect...
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Two types of iterative learning controllers for batch processes are presented in this paper. The controllers not only contain a feedforward term, but also incorporate a feedback term and a difference term. First, vector lifting technology is employed to describe all the inputs or outputs of a single batch. Second, we utilize matrix inversion and exponentiation operations to obtain the sufficient condition for the monotonic convergence of the error norm, and give the upper bound of the error at any time of each iteration, which is not only limited by the control gains, but also related to the number of iterations and the time. Third, when choosing the control gains, the guidance is given according to the upper bound of the tracking error, and the suboptimal learning gains are yielded by applying the distribution of the matrix eigenvalues. Finally, four examples are applied to verify the effectiveness of the algorithm.
In a multisensor system, each sensor typically requires independent reference tracking while conflicts arise due to differing desired inputs for different sensors. This scenario presents an exemplary incompatible mult...
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In a multisensor system, each sensor typically requires independent reference tracking while conflicts arise due to differing desired inputs for different sensors. This scenario presents an exemplary incompatible multiobjective tracking problem (IMOTP), which can be resolved as a multiobjective optimization problem (MOOP). We propose an iterative learning control strategy to resolve conflicts between sensors. First, we elaborate on the Pareto optimal solution (POS) set associated with the MOOP. Subsequently, we derive an update direction for Pareto improvement based on gradient-based algorithms for MOOP and establish a learningcontrol algorithm ensuring that each update is a Pareto improvement and converges to a POS. These technical advancements effectively overcome tracking conflicts in multisensor systems. Illustrative simulations are provided to validate the theoretical results.
This paper investigates the stabilization of Euler-Bernoulli beam systems modeled by a partial differential equation (PDE) with unknown time -varying disturbance. An iterative learning controller is designed using onl...
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This paper investigates the stabilization of Euler-Bernoulli beam systems modeled by a partial differential equation (PDE) with unknown time -varying disturbance. An iterative learning controller is designed using only boundary state feedback to realize the vibration control subject to unknown boundary disturbance. The wellposedness for the closed -loop system is given by the operator semigroup theory. Furthermore, the exponentially stable for the closed -loop system is proved by the Lyapunov method. The comparisons with existing results are made to demonstrate the effectiveness and advantages of the proposed boundary iterative learning control method.
In this article, robust iterative learning controls are proposed for a flexible wing with iteration-varying disturbances and references having unknown coefficients. The unknown basis functions of the disturbances and ...
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In this article, robust iterative learning controls are proposed for a flexible wing with iteration-varying disturbances and references having unknown coefficients. The unknown basis functions of the disturbances and references are supposed to be from an exosystem with unknown initial values. Then, a higher internal model is used to describe the unknown iteration-varying property. A strongly coupled reference model, inspired by the fourth-order ODEs of the Timoshenko beam equation, is firstly proven to admit bounded solutions. In this case, feedforward controls are designed for the flexible wing system, where the iteration-varying input disturbances are divided into unknown constants and known iteration-varying states. By finding two adaption laws, robust iterative learning controls are designed to guarantee the convergence of the tracking errors along the iteration axis, as well as the boundedness of the closed-loop system. Simulation examples are further provided for the robust output regulation of the wing.
This paper presents an extension method of iterative learning control (ILC) to address the applications associated with non-repetitive time-varying systems (NTVSs). Conventional ILC approaches employ fixed nominal sys...
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This paper presents an extension method of iterative learning control (ILC) to address the applications associated with non-repetitive time-varying systems (NTVSs). Conventional ILC approaches employ fixed nominal system models, but non-repetitive time-varying models may lead to accumulated model uncertainties, which fails to satisfy the robust convergence conditions. To tackle this issue, a novel ILC algorithm with parameter estimation is proposed using back propagation neural network. This algorithm incorporates an approach that utilizes Bayesian regularization training mechanism to accurately estimate non-repetitive time-varying parameters. Through comprehensive experiment on Monolithic XY Stage, the performance of proposed algorithm is validated to demonstrate its feasibility and effectiveness while handling tasks on NTVSs.
This paper investigates the learning consensus control and formation control of nonlinear uncertain parameterized multi-agent systems with non-identical partially unknown control directions, which generalizes the rese...
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This paper investigates the learning consensus control and formation control of nonlinear uncertain parameterized multi-agent systems with non-identical partially unknown control directions, which generalizes the research results of linear uncertain parameterized multi-agent systems. Based on neural networks and Fourier series expansion, a new neural network approximator is constructed to approximate the nonlinear uncertain parameterized dynamics. Combined with the iterative learning control and adaptive control method, a novel adaptive iterative learning control law is designed, in which the parameter adaptive iterativelearning estimation is used to eliminate the influence of approximation errors, unpredictable leader dynamics and unknown control directions. Then, a new parameterized composite energy function is constructed to demonstrate the stability of the entire consistent systems and formation systems. On this basis, the advantages of protocols in undirected and directed topologies were discussed. Finally, the simulation results verify the effectiveness of the proposed control algorithm.
In modern smart manufacturing, robots are often connected via a network, and their task can change according to a predetermined program. iterative learning control (ILC) is widely used for robots executing high-precis...
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In modern smart manufacturing, robots are often connected via a network, and their task can change according to a predetermined program. iterative learning control (ILC) is widely used for robots executing high-precision operations. Under network conditions, the efficiency of ILC algorithms may decrease if the program is restructured. In particular, the learning error may temporarily increase to an unacceptable value when changing the reference trajectory. This paper considers a networked system with the following features: the reference trajectory and parameters change between passes according to a known program, agents are subjected to random disturbances, and measurements are carried out with noise. In addition, the network topology changes due to the disconnection of some agents from the network and the connection of new agents to the network according to a given program. A distributed ILC design method is proposed based on vector Lyapunov functions for repetitive processes in combination with Kalman filtering. This method ensures the convergence of the learning error and reduces its increase caused by changes in the reference trajectory and network topology. The effectiveness of the proposed method is confirmed by an example.
The tricalcium neutralization process (TNP) is a key recovery process in the citric acid production process. The amount of calcium carbonate added needs to be controlled to ensure the pH of the reactants within the ta...
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The tricalcium neutralization process (TNP) is a key recovery process in the citric acid production process. The amount of calcium carbonate added needs to be controlled to ensure the pH of the reactants within the target range at the terminal of every batch. But the random initial pH has a great influence on the stability of the terminal pH. In this work, an iterative learning control (ILC)-based control strategy is proposed to optimize the addition of calcium carbonate. First, the terminal iterative learning control (TILC) is performed and the optimal input of the process can be obtained. Then, an initial disturbance compensation controller optimized by ILC is proposed. The results of the TNP control experiments demonstrate that the suggested control strategy can suppress the disturbances and achieve terminal pH control.
This paper proposes two kinds of iterative learning control (ILC) schemes for a class of the distributed parameter systems based on sensor-actuator networks which can be described by hyperbolic partial differential eq...
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This paper proposes two kinds of iterative learning control (ILC) schemes for a class of the distributed parameter systems based on sensor-actuator networks which can be described by hyperbolic partial differential equations. A D-type ILC algorithm is first considered and the convergent condition of the output error is obtained via the contraction mapping methodology. Then, the PD-type ILC algorithm is considered in this hyperbolic distributed parameter systems based on sensor-actuator networks. Finally, a cable equation with air and structural damping is given to illustrate the effectiveness of the proposed methods.
This paper considers a linear discrete-time system operating in a repetitive mode to track a reference trajectory with a required accuracy. The control variable has a delay along the sample trajectory, and saturation-...
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This paper considers a linear discrete-time system operating in a repetitive mode to track a reference trajectory with a required accuracy. The control variable has a delay along the sample trajectory, and saturation-type constraints are imposed. We introduce a new method for designing an iterative learning control law that depends on the delay and ensures the required accuracy of tracking. A numerical example demonstrates the effectiveness of this method.
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