Reliability of nonlinear stochastic controlled systems considering the dynamics of sensors and actuators

2021 ◽  
pp. 107754632110037
Author(s):  
Sun Jiaojiao ◽  
Xia Lei ◽  
Ying Zuguang ◽  
Huan Ronghua ◽  
Zhu Weiqiu
Keyword(s):  
Closed Loop ◽  
First Passage Time ◽  
Hamiltonian Function ◽  
Small Time ◽  
Kolmogorov Equation ◽  
Sensors And Actuators ◽  
First Passage ◽  
Controlled System ◽  
Main Structure ◽  
Controlled Systems

A closed-loop controlled system usually consists of the main structure, sensors, and actuators. The dynamics of sensors and actuators may influence the motion of the main structure. This article presents an analytical study on the first-passage reliability of a nonlinear stochastic controlled system under the consideration of the dynamics of sensors and actuators. The coupled dynamic equations of the controlled systems with sensors and actuators are first given, which are further integrated into a controlled, randomly excited, dissipated Hamiltonian system. By applying the stochastic averaging method for quasi-Hamiltonian systems, a one-dimensional averaged differential equation for the Hamiltonian function is obtained. The backward Kolmogorov equation associated with the averaged equation is then derived for the first-passage reliability analysis, from which the approximate reliability function and probability density of first-passage time are obtained. The accuracy of the proposed procedure is demonstrated by an example. A comparative analysis of the reliability of the system with/without sensors and actuators is carried out, which indicates that ignoring sensors and actuators will make underestimation of the reliability of the closed-loop system with small time. However, when time increases, there appears the opposite trend. Our findings provide a reference for control strategy design.

A three dimensional dam break flow: Small time behavior

2021 ◽  
Vol 110 ◽  
pp. 102583
Author(s):  
Elona Fetahu ◽  
Oguz Yilmaz
Keyword(s):  
Three Dimensional ◽  
Small Time ◽  
Dam Break ◽  
Time Behavior ◽  
Dam Break Flow

Stress measurement for steel slender waveguides based on the nonlinear relation between guided wave group velocity and stress

Measurement ◽  
2021 ◽  
pp. 109465
Author(s):  
Zuohua Li ◽  
Yingzhu Wang ◽  
Junchao Zheng ◽  
Nanxi Liu ◽  
Ming Li ◽  
...  
Keyword(s):  
Group Velocity ◽  
Stress Measurement ◽  
Guided Wave ◽  
Wave Group ◽  
Nonlinear Relation

scholarly journals A Generalized Dynamic Potential Energy Model for Multiagent Path Planning

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Liu He ◽  
Haoning Xi ◽  
Tangyi Guo ◽  
Kun Tang
Keyword(s):  
Path Planning ◽  
Potential Energy ◽  
Multiagent System ◽  
Small Time ◽  
Energy Model ◽  
Dijkstra Algorithm ◽  
Energy Field ◽  
Space Potential ◽  
Dynamic Potential ◽  
Planning Decision

Path planning for the multiagent, which is generally based on the artificial potential energy field, reflects the decision-making process of pedestrian walking and has great importance on the field multiagent system. In this paper, after setting the spatial-temporal simulation environment with large cells and small time segments based on the disaggregation decision theory of the multiagent, we establish a generalized dynamic potential energy model (DPEM) for the multiagent through four steps: (1) construct the space energy field with the improved Dijkstra algorithm, and obtain the fitting functions to reflect the relationship between speed decline rate and space occupancy of the agent through empirical cross experiments. (2) Construct the delay potential energy field based on the judgement and psychological changes of the multiagent in the situations where the other pedestrians have occupied the bottleneck cell. (3) Construct the waiting potential energy field based on the characteristics of the multiagent, such as dissipation and enhancement. (4) Obtain the generalized dynamic potential energy field by superposing the space potential energy field, delay potential energy field, and waiting potential energy field all together. Moreover, a case study is conducted to verify the feasibility and effectiveness of the dynamic potential energy model. The results also indicate that each agent’s path planning decision such as forward, waiting, and detour in the multiagent system is related to their individual characters and environmental factors. Overall, this study could help improve the efficiency of pedestrian traffic, optimize the walking space, and improve the performance of pedestrians in the multiagent system.

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