In flexible redundantly-driven multi-DOF systems, like living beings, the representation of redundant kinematics including the diversity of solutions, is crucial for leveraging its distinctive characteristics. This pa...
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ISBN:
(纸本)9798350377712;9798350377705
In flexible redundantly-driven multi-DOF systems, like living beings, the representation of redundant kinematics including the diversity of solutions, is crucial for leveraging its distinctive characteristics. This paper proposes an active learning framework for forward and inverse modeling of complex kinematics that improves expressions of control space, task space, and null space. It consists of a Variational Auto Encoder (VAE)-type network that internally holds expressions of control space, task space, and null space, and an algorithm for selecting new data using the cross-entropy method. The validity of the proposed system was verified using a tensegrity manipulator driven by 40 pneumatic cylinders. As a result, it was confirmed that active learning contributed to achieving the entire range of motion covered and a well-organized representation of the null space.
Wastewater treatment is indispensable to the functioning of urban society, and its optimal control has enormous social benefits. However, precise modelling of the unstable and complex treatment process is challenging ...
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Wastewater treatment is indispensable to the functioning of urban society, and its optimal control has enormous social benefits. However, precise modelling of the unstable and complex treatment process is challenging yet crucial to the adaptive dynamic programming method. In this article, an adaptive critic algorithm with variational inference is designed to address the optimal control problem of nonlinear discrete-time systems, along with the convergence analysis. Based on the recorded system trajectory, the variational autoencoder is utilized to approximate the behavior policy of the offline dataset without system modelling and online interaction. Through policy iteration learning, the actor-critic structure can amend the policy generated by the variational autoencoder to achieve the optimal control objective. Simulations on a nonlinear system and the wastewater treatment process have verified that the proposed approach outperformed the behavior policy. driven by the wastewater treatment process data derived from the incremental proportional-integral-derivative controller, the proposed approach can produce an optimal control policy of less tracking error and cost. Note to Practitioners-When dealing with an unknown system with complex dynamics, it is more feasible to improve the acceptable performance of the existing control policy based on the system's trajectory than to obtain an excelling policy. Motivated by batch reinforcement learning, learning from offline data can avoid the online interaction between the system and the adaptive dynamic programming algorithm, which could lead to exploratory errors during online learning. Specifically, using a model-free adaptive dynamic programming algorithm, the parameters of the controller are instantly updated based on the experience replay buffer sampled from the online trajectory data. However, online exploration determines the update, and there is no guarantee that the system will converge every time. As a specific typ
In practice, data-driven soft sensors often face data shortages in modeling. data augmentation technology has offered a feasible solution for this problem in recent years. However, how to better use virtual data for d...
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ISBN:
(纸本)9798350321050
In practice, data-driven soft sensors often face data shortages in modeling. data augmentation technology has offered a feasible solution for this problem in recent years. However, how to better use virtual data for data augmentation is still an open topic. In this paper, a novel data augmentation soft sensing method is proposed. It uses Gaussian mixture models (GMM) to generate virtual data for the training dataset, and developed a double-weighted neural network (dwDNN) for weighted regression modeling. On top of that, the Bayesian optimization algorithm is applied to the weight selection of dwDNN to further enhance the efficiency and effectiveness of GMM-dwDNN on virtual data. In the end, a real industrial case is used to illustrate the superiority of the proposed approach in soft sensing.
This paper concerns with the fixed-time control problem of nonlinear non-affine system. First, based on a Taylor series expansion, the nonlinear non-affine system is transformed into an affine system. Second, by using...
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ISBN:
(纸本)9798350321050
This paper concerns with the fixed-time control problem of nonlinear non-affine system. First, based on a Taylor series expansion, the nonlinear non-affine system is transformed into an affine system. Second, by using norm-normalized sign functions and providing sufficient Lyapunov conditions, it is shown that the nonlinear non-affine system can be achieved synchronization in a fixed time, regardless of its initial value. In addition, the settling time is calculated by using an enhanced estimation method. Third, compared with the classical calculate method, a switching sliding-mode control technique is adopted to deal with the possible singularity problem.
Self-triggered model predictive control (ST-MPC) is widely applied in various aspects currently, however, the ST-MPC mechanisms that have seldom been developed consider the possible malicious false data injection (FDI...
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ISBN:
(纸本)9798350321050
Self-triggered model predictive control (ST-MPC) is widely applied in various aspects currently, however, the ST-MPC mechanisms that have seldom been developed consider the possible malicious false data injection (FDI) attacks in the cyber-physical system (CPS). Therefore, in this paper, a novel resilient ST-MPC strategy based on input reconstruction (IR) against FDI attacks is proposed for a nonlinear input-affine discrete-time system with state and input constraints, which combines both cyber security and resource consumption. More specifically, when faced with FDI attacks in controller-to-actuator (C-A) channels at the triggering instants, on the actuator side, two key controldata are selected to reconstruct input control signals for application into the system, otherwise, the optimal input control signals will be applied into the controlled system. Furthermore, a resilient ST-MPC algorithm with a dual-mode control strategy is proposed, and its closed-loop stability is also analyzed, in which the state constraint is elaborated. Finally, a simulation and its resultant comparisons illustrate the effectiveness of the proposed method.
This paper investigates the speed tracking control issue of a permanent magnet synchronous motor (PMSM). A speed tracking controller based on an adaptive extended harmonic state observer and an extended state observer...
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ISBN:
(纸本)9798350321050
This paper investigates the speed tracking control issue of a permanent magnet synchronous motor (PMSM). A speed tracking controller based on an adaptive extended harmonic state observer and an extended state observer is proposed under the PMSM non-cascaded structure to suppress multiple disturbances and improve the speed tracking performance. Specifically, an adaptive extended harmonic state observer is designed to estimate mismatched periodic and mismatched aperiodic disturbances with uncertain frequencies, and another extended state observer is developed to estimate matched disturbances. Based on the disturbance estimates, a linear feedback controller is designed to solve the PMSM speed tracking problem under matched and mismatched disturbances. Finally, the effectiveness of the proposed control scheme is verified by the simulation study.
This paper considers the problem of containment control for multi-input multi-output (MIMO) nonlinear multi-agent systems (MASs) with output saturation and aperiodic denial-of-service (DoS) attacks. By applying the dy...
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This paper considers the problem of containment control for multi-input multi-output (MIMO) nonlinear multi-agent systems (MASs) with output saturation and aperiodic denial-of-service (DoS) attacks. By applying the dynamic linearization method, the nonlinear systems are modified to an equivalent linear data model. Based on the inputs and saturated outputs data, a new data-driven containment control algorithm in the presence of aperiodic DoS attacks is developed, which mainly includes the following perspectives: 1) based on the historical information of the MASs, a switched error system is designed to decrease the impact of aperiodic DoS attacks, where the time duration was constrained due to the limitation of attackers' energy;2) the relation between measured error and tracking error is constructed to deal with the difficulties of incomplete data suffered from output saturation;3) with the help of contraction mapping method and mathematical induction approach, the boundedness of containment error is guaranteed by the convergence of the control strategy in such an insecure environment. Numerical simulations are given to validate the effectiveness of the framework. Note to Practitioners-This paper studies the containment control problem for MIMO nonlinear MASs, which has application value in robotic systems, intelligent transportation, multiple spacecraft systems, and other fields. Note that these systems are notably susceptible to network attacks and saturation nonlinearity, which may decrease the system performance or even cause instability. Since the agent dynamics generally are not accurate even unavailable, the existing model-based technologies are inappropriate for MIMO nonlinear MASs. Therefore, in light of the challenge aroused by aperiodic DoS attacks and output saturation, a novel switched error system-based model-free adaptive containment control approach is developed to preserve data integrity while the stability of containment error is guaranteed. Numeric
In this paper, a new dynamic nonlinear gradient observer-based extremum-seeking control algorithm (DNGO-based ESC) and a dynamic Jacobian matrices estimator-based self-optimizing control algorithm (DJE-based SOC) are ...
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ISBN:
(纸本)9798350321050
In this paper, a new dynamic nonlinear gradient observer-based extremum-seeking control algorithm (DNGO-based ESC) and a dynamic Jacobian matrices estimator-based self-optimizing control algorithm (DJE-based SOC) are designed for the control of two-stage anaerobic digestion (TSAD). None of two algorithms requires priori knowledge about the system model. The proposed algorithms are compared with the classical extremum-seeking control algorithm and the Kalman Filter based Newton extremum-seeking control algorithm. The simulation results show that in the presence of disturbance both of proposed control algorithms can maintain the system at the optimal operating point and drive the hydrogen and methane yields to the extreme point. Future work is to validate the designed control algorithm in an actual two-stage anaerobic digestion process.
Considering partially known transition rates and saturating actuators, the finite-time H-infinity control problem for a class of singular discrete-time Markovian jump delayed systems is studied in this article. First,...
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ISBN:
(纸本)9798350321050
Considering partially known transition rates and saturating actuators, the finite-time H-infinity control problem for a class of singular discrete-time Markovian jump delayed systems is studied in this article. First, by employing local sector conditions and an appropriate Lyapunov function, a hidden Markov model based state feedback controller is designed to guarantee that the resulted closed-loop constrained system is mean-square locally finite-time stabilizable, and the closed-loop cost function value is not more than a specified upper bound. Furthermore, some sufficient conditions for the solution to this problem are derived in terms of linear matrix inequalities. Finally, a numerical example is provided to demonstrate the effectiveness of proposed method.
This paper examines a category of second-order nonlinear systems' predefined-time tracking control issue restricted by the state and input from the control. The safety predefined-time control framework proposed by...
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ISBN:
(纸本)9798350321050
This paper examines a category of second-order nonlinear systems' predefined-time tracking control issue restricted by the state and input from the control. The safety predefined-time control framework proposed by this work aims at tracking a desired trajectory in a predefined time while maintaining safe system outputs and control inputs. The safety predefined-time controller is specifically created by a safety filter utilizing the control barrier function approach and a predefined-time controller on the basis of the backstepping technique. The predefined-time controller establishes an explicit relation between the controller parameters and the convergence time constraint. Moreover, the safety filter enforces the state and control input constraints by constructing a quadratic programming problem. In an effort to demonstrate the feasibility of the safety predefined-time controller, a second-order practical system is simulated.
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