In this paper, we consider the control of large-scale processes with both input and state couplings. A distributed model predictive control(MPC) strategy for tracking based on the reference trajectories is presented. ...
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ISBN:
(纸本)9781479947249
In this paper, we consider the control of large-scale processes with both input and state couplings. A distributed model predictive control(MPC) strategy for tracking based on the reference trajectories is presented. The proposed distributed MPC strategy requires decomposing a large-scale system into several smaller ones and solving convex optimization problems independently. Distributed MPC tracking strategies for unconstrained and constrained processes are presented, respectively. An iterative algorithm is presented to coordinate the distributed MPC controllers. The proposed algorithm is applied to a four-tank process to demonstrate the effectiveness.
A novel fault integration method is proposed in this paper for manufacturing system models given in the form of timed colored Petri nets. The faults are assumed to have a stochastic nature and are represented in the f...
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ISBN:
(纸本)9789077381861
A novel fault integration method is proposed in this paper for manufacturing system models given in the form of timed colored Petri nets. The faults are assumed to have a stochastic nature and are represented in the form of transitions firing in stochastic way with known fault probabilities in the system model. A novel fault effect propagation method was also developed, that can be used to compute the probabilities of the possible faulty and non-faulty intermediate and final states of the system using the probabilities of faults and the occurrence graph. The faultless and fault containing models were implemented in CPNTools both for non-timed and timed cases. A software module was also developed for the proposed probabilistic fault propagation analysis. The proposed methods and tools were demonstrated using a simple case study.
A novel on-line diagnosis method is proposed in this paper that uses a qualitative dynamic model of the system and its colored Petri nets model. The model contains both the normal and the possible faulty operational m...
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ISBN:
(纸本)9789077381861
A novel on-line diagnosis method is proposed in this paper that uses a qualitative dynamic model of the system and its colored Petri nets model. The model contains both the normal and the possible faulty operational modes of the system. The deviation between the normal and faulty modes is characterized based on P-HAZID tables. The actual system state can be searched on the occurrence graph constructed in advance. Starting from this node the possible consequences and root causes can be determined on-line with traversing on the graph. The proposed method is illustrated on simple case studies.
As well-known, model predictive control is closely related to optimal control. This paper studies relationships between them and provides a unified framework for optimality analysis of model predictive controllers (MP...
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As well-known, model predictive control is closely related to optimal control. This paper studies relationships between them and provides a unified framework for optimality analysis of model predictive controllers (MPC). The optimality is evaluated by comparing total performance of MPC with finite and infinite horizon optimal cost. Based on relaxed value iteration method, upper and lower bounds of optimality evaluation functions are expressed explicitly in terms of optimization horizon. These results reveal detailed characteristics on performance of closed-loop MPC systems due to using “receding horizon optimization” implementation style.
This paper proposes a novel nonlinear distributed consensus protocol of the finite-time consensus problems of leader-follower multi-agent systems based on the distributed consensus error functions. It is proved that t...
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This paper proposes a novel nonlinear distributed consensus protocol of the finite-time consensus problems of leader-follower multi-agent systems based on the distributed consensus error functions. It is proved that the leader-follower multi-agent systems under this nonlinear protocol can reach the consensus in finite time in the scenarios with fixed topology and two kinds of switching topologies, respectively. The results are also extended to the case with directed communication topology. Finally, some examples and simulation results are given to illustrate the effectiveness of the proposed control protocols.
Sensor networks have been widely utilized in various applications. In large wind farms, numerous sensor nodes are deployed across the field for monitoring purpose. They are required to work in harsh environment and us...
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Sensor networks have been widely utilized in various applications. In large wind farms, numerous sensor nodes are deployed across the field for monitoring purpose. They are required to work in harsh environment and usually undergo unexpected failures. This paper introduces a new method to model nodes of sensor networks by using two-layer neural networks (NN). Each node's dynamics and interconnections with other sensor network nodes are integrated into the model, whose accuracy is guaranteed by the NN's universal approximation property. Furthermore, the model can be subsequently employed to detect any incipient failures which can be modeled as a nonlinear function of state and input variables. An additional NN along with a novel simplified updating law is utilized for self-diagnostics, whose output can declare a failure alarm if it exceeds a certain threshold. Mathematical analysis is substantiated with simulation results.
Walking on irregular terrain is usually a common task for a quadruped robot. It is however difficult to control the robot in this situation as undesirable impulse force by collision between the foot of robot and obsta...
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Walking on irregular terrain is usually a common task for a quadruped robot. It is however difficult to control the robot in this situation as undesirable impulse force by collision between the foot of robot and obstacles makes the robot unstable. This paper presents a hybrid Force-Posture Feedback Compensation (FPFC) controller for a quadruped robot with high payload walking on irregular terrain. In order to make the robot walk stably on irregular terrain, the proposed controller utilizes the feedback signals detected by force sensor and gyroscope to adjust every leg of the robot in real-time. The foot trajectory is scheduled based on the Bezier curve method in order to improve the stability of quadruped robot. Simulations of crawling gait on irregular terrain have been performed. The results have verified that the proposed methods have better stability and performance for walking on the irregular terrain.
This paper is concerned with the state estimation problem for nonlinear systems with unknown covariance of process noise. The advantages of recently developed High-degree Cubature Kalman Filter (HCKF) are significant ...
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This paper is concerned with the state estimation problem for nonlinear systems with unknown covariance of process noise. The advantages of recently developed High-degree Cubature Kalman Filter (HCKF) are significant with its easy to implement and better estimation accuracy. However, it has bad robustness on modeling uncertainty for practical applications. To overcome the limitations of the HCKF, an Adaptive HCKF (AHCKF) is proposed by combing strong tracking filtering and Sage-Husa estimator. In the proposed state estimator, a fading factor is used to correct one state prediction covariance while the Sage-Husa estimator is adopted to recursively estimate the unknown process noise statistics. Therefore, the AHCKF can obtain better robustness and accuracy comparing with the conventional HCKF. Simulation examples on target tracking are demonstrated the validity of the proposed algorithms.
作者:
Xin CaiShaoyuan LiNing LiKang LiDepartment of Automation
Shanghai Jiao Tong University and Key Laboratory of System Control and Information Processing Ministry of Education Shanghai 200240 P. R. China School of Electronics
Electrical Engineering and Computer Science The Queen's University Belfast Belfast BT7 1NN UK
This paper addresses the problem of infinite time performance of model predictive controllers applied to constrained nonlinear systems. The total performance is compared with a finite horizon optimal cost to reveal pe...
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This paper addresses the problem of infinite time performance of model predictive controllers applied to constrained nonlinear systems. The total performance is compared with a finite horizon optimal cost to reveal performance limits of closed-loop model predictive controlsystems. Based on the Principle of Optimality, an upper and a lower bound of the ratio between the total performance and the finite horizon optimal cost are obtained explicitly expressed by the optimization horizon. The results also illustrate, from viewpoint of performance, how model predictive controllers approaches to infinite optimal controllers as the optimization horizon increases.
Load distribution is a key technology in hot strip rolling process, which directly influences strip product quality. A multi-objective load distribution model, which takes into account the rolling force margin balance...
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Load distribution is a key technology in hot strip rolling process, which directly influences strip product quality. A multi-objective load distribution model, which takes into account the rolling force margin balance, roll wear ratio and strip shape control, is presented. To avoid the selection of weight coefficients encountered in single objective optimization, a multi-objective differential evolutionary algorithm, called MaximinDE, is proposed to solve this model. The experimental results based on practical production data indicate that MaximinDE can obtain a good pareto-optimal solution set, which consists of a series of alternative solutions to load distribution. Decision-makers can select a trade-off solution from the pareto-optimal solution set based on their experience or the importance of ob- iectives. In comparison with the empirical load distribution solution, the trade-off solution can achieve a better per- formance, which demonstrates the effectiveness of the multi-objective load distribution optimization. Moreover, the conflicting relationship among different objectives can be also found, which is another advantage of multi-objective load distribution optimization.
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