Neural-network-based identification and control of a thin plate using piezoelectric actuators and sensors

This paper proposes a novel neural network approach for the identification and control of a thin simply supported plate. For the control purpose, the piezoelectric sensors and actuators are attached on a flexible structure. The motion behaviour of a two-dimensional model of piezoelectric materials bounded to the surface of the plate is analytically investigated. A novel linear differential inclusion is developed for a class of multilayer feedforward networks. With this technique, it is shown that the plant identified by the neural network can be represented as a linear time-invariant system. On the basis of the identified model, advanced linear control theory can be directly applied to design the stabilizing flexible structure controller. Extensive simulations are conducted to show the effectiveness of the proposed method.     

Refined sandwich model for the vibration of beams with embedded shear piezoelectric actuators and sensors

This work extends a previously presented refined sandwich beam finite element (FE) model to vibration analysis, including dynamic piezoelectric actuation and sensing. The mechanical model is a refinement of the classical sandwich theory (CST), for which the core is modelled with a third-order shear deformation theory (TSDT). The FE model is developed considering, through the beam length, electrically: constant voltage for piezoelectric layers and quadratic third-order variable of the electric potential in the core, while mechanically: linear axial displacement, quadratic bending rotation of the core and cubic transverse displacement of the sandwich beam. Despite the refinement of mechanical and electric behaviours of the piezoelectric core, the model leads to the same number of degrees of freedom as the previous CST one due to a two-step static condensation of the internal dof (bending rotation and core electric potential third-order variable). The results obtained with the proposed FE model are compared to available numerical, analytical and experimental ones. Results confirm that the TSDT and the induced cubic electric potential yield an extra stiffness to the sandwich beam.     

Intelligent identification and control using improved fuzzy particle swarm optimization

This paper presents a novel improved fuzzy particle swarm optimization (IFPSO) algorithm to the intelligent identification and control of a dynamic system. The proposed algorithm estimates optimally the parameters of system and controller by minimizing the mean of squared errors. The particle swarm optimization is enhanced intelligently by using a fuzzy inertia weight to rationally balance the global and local exploitation abilities. In the proposed IFPSO, every particle dynamically adjusts inertia weight according to particles best memories using a nonlinear fuzzy model. As a result, the IFPSO algorithm has a faster convergence speed and a higher accuracy. The performance of IFPSO algorithm is compared with advanced algorithms such as Real-Coded Genetic Algorithm (RCGA), Linearly Decreasing Inertia Weight PSO (LDWPSO) and Fuzzy PSO (FPSO) in terms of parameter accuracy and convergence speed. Simulation results demonstrate the effectiveness of the proposed algorithm.     

Working equations for piezoelectric actuators and sensors

A new solution to the force, displacements, and charges developed in piezoelectric beams is derived. Differing from previous solutions, this development determines the neutral axis where the bending strains are zero and results in a closed form solution (without matrix inversion). With the closed form, simplifications become evident which increase understanding and facilitate calculations. These equations are than expanded to account for axial, built-in strains in the beam. A design example where axial forces exerted by the piezoelectric layer are important is presented     

Robust optimization using multi-objective particle swarm optimization

This article proposes an algorithm to search for solutions which are robust against small perturbations in design variables. The proposed algorithm formulates robust optimization as a bi-objective optimization problem, and fi nds solutions by multi-objective particle swarm optimization (MOPSO). Experimental results have shown that MOPSO has a better performance at fi nding multiple robust solutions than a previous method using a multi-objective genetic algorithm.     

Mean arterial pressure control system using model predictive control and particle swarm optimization

Microsystem Technologies - Linear controllers have been designed to regulate mean arterial pressure (MAP) in treating various cardiovascular diseases. For patients with hemodynamic fluctuations,...     

群活性与粒子群优化的稳定性分析

在探讨粒子轨迹的随机过程的基础上,用根轨迹特征值的谱半径来描述粒子群优化的PSO动态系统的稳定性区域;提出并结合实例用群活性刻画了PSO稳定区域中不同参数区间上群行为的动态特征,利用不动点技术通过数值实验描绘出PSO群活性谱及性能图,解释了先前一些文献上提出的典型参数集之所以能够取得满意性能的理由,利用PSO稳定三角中线提出保证PSO收敛性能的参数设置指导策略.     

Dynamical information fusion of heterogeneous sensors for 3D tracking using particle swarm optimization

This paper presents a new method for three dimensional object tracking by fusing information from stereo vision and stereo audio. From the audio data, directional information about an object is extracted by the Generalized Cross Correlation (GCC) and the object’s position in the video data is detected using the Continuously Adaptive Mean shift (CAMshift) method. The obtained localization estimates combined with confidence measurements are then fused to track an object utilizing Particle Swarm Optimization (PSO). In our approach the particles move in the 3D space and iteratively evaluate their current position with regard to the localization estimates of the audio and video module and their confidences, which facilitates the direct determination of the object’s three dimensional position. This technique has low computational complexity and its tracking performance is independent of any kind of model, statistics, or assumptions, contrary to classical methods. The introduction of confidence measurements further increases the robustness and reliability of the entire tracking system and allows an adaptive and dynamical information fusion of heterogenous sensor information.     

Active control of building structures using piezoelectric actuators

Active control strategy is an innovative method for enhancing structural functionality against strong ground motions. In this paper the performance of piezoelectric actuators for active control of the seismic responses of tall buildings is investigated. Three-dimensional modeling of the building is considered where three degrees of freedom including displacements in two perpendicular horizontal directions and rotation about the vertical axis are corresponded to each floor. The piezoelectric actuators are hosted at the bottom of the columns and the controlling forces produced by actuators are considered in the equations of motion of the buildings. Linear quadratic regulator (LQR), supervisory fuzzy controller (SFC) and fuzzy logic controller (FLC) are applied in the control designs. For the numerical studies, a real 10 story building subjected to an ensemble of 20 worldwide acceleration records is considered. Since there are many possible positions for placement of piezoelectric actuators in the test building, genetic algorithm is used for finding the optimal arrangement of actuators in order to achieve maximum reduction in building responses. The comparison of the controlled and uncontrolled responses of the test building indicates that the piezoelectric actuators are able to provide considerable reductions in buildings’ seismic responses. Also the performance of the above three controllers reveals that the fuzzy controller is much more effective than the two others.     

一种求解多峰函数优化问题的量子行为粒子群算法

介绍了一种利用量子行为粒子群算法（QPSO）求解多峰函数优化问题的方法。为此,在QPSO中引进一种物种形成策略,该方法根据群体微粒的相似度并行地分成子群体。每个子群体是围绕一个群体种子而建立的。对每个子群体通过QPSO算法进行最优搜索,从而保证每个峰值都有同等机会被找到,因此该方法具有良好的局部寻优特性。将基于物种形成的QPSO算法与粒子群算法(PSO)对多峰优化问题的结果进行比较。对几个重要的测试函数进行仿真实验结果证明,基于物种形成的QPSO算法可以尽可能多地找到峰值点,峰值收敛性能优于PSO。     

Shape optimization of piezoelectric energy harvesters based on isogeometric analysis and particle swarm optimization

Microsystem Technologies - Shape optimization of piezoelectric energy harvesters (PEH) is deemed to be one of the most effective methods to enhance energy efficiency. In this paper, we propose a...     

改进粒子群优化的关联交叉口协调控制

提出了基于改进粒子群优化的关联交叉口协调控制方法。建立了关于排队长度的交通流模型和协调控制目标函数,利用改进粒子群算法对各交叉口绿信比和考虑双向绿波的相位差进行求解,实现了关联交叉口的最优控制。以实际采集的几个关联交叉口的交通数据仿真表明,相比单向绿波控制和感应控制,所提方法可有效减少延误和平均排队长度。     

多样性反馈与控制的粒子群优化算法

针对粒子群优化(PSO)算法的早熟收敛问题,提出了一种多样性反馈与控制的粒子群优化 (DFCPSO)算法。该算法在搜索过程中根据多样性反馈信息,动态调整算法参数,改善了搜索次数在多样性曲线上的分布情况。当多样性或群体适应度方差下降到给定的阈值时,通过基于最优点排斥的初始化操作,高效率发散,使粒子飞离聚集区域,重新开始搜索,从而使种群多样性保持在合理范围内,避免了早熟收敛现象。对多个标准测试函数的实验结果表明,与当前多样性控制的粒子群优化(DCPSO)算法相比,DFCPSO算法在复杂优化问题和多模态优化问题中具有更强的全局搜索能力。     

Self-adapting control parameters in particle swarm optimization

Particle Swarm Optimization (PSO) is a powerful nature-inspired metaheuristic optimization method. Compared to other methods, PSO can determine the optimal solution in fewer evaluations and generally performs more efficiently and effectively. However, researches show that the PSO method suffers from premature convergence and a dependence on the initial control settings. Due to these shortcomings, the application of PSO may lead to failure in obtaining the global optimal solution. In this work, modifications were performed on the original PSO algorithm to adapt the control parameters to the circumstances of the particles at a specific moment. The proposed method is known as the Unique Adaptive Particle Swarm Optimization (UAPSO). In the developed approach, constraints were handled by forcing the particles to learn from their feasible solutions only. Therefore, the constraint handling technique worked in accord with the adapting scheme to ensure that the particles were adapting to the environment by directing itself to the feasible regions. The performance of UAPSO was verified by a comparative study involving eight benchmark constrained optimization problems and a real-world design problem. The numerical results showed the superiority of UAPSO compared to the selected state-of-the-art metaheuristic methods and PSO variants, its ability in avoiding premature convergence and its consistency and efficiency.     

控制系统的辨识建模及微粒群优化设计

针对控制系统的传递函数建模与控制器的参数优化问题,提出了基于Prony和微粒群优化（PSO）算法的设计方案。首先在被控对象的输入端施加一个脉冲信号,然后对其输出信号进行Prony分析,得出该被控对象的传递函数,最后采用改进PSO算法进行控制器的参数优化设计。基于辨识的Prony算法可快速准确得出被控对象的传递函数;基于T-S模型模糊自适应的改进PSO算法（T-SPSO算法）依据种群当前最优性能指标和惯性权重自适应惯性权重取值,较好解决了PSO算法的早熟问题,可以更好地优化控制器参数。该方案实现了控制系统的精确建模与优化设计,仿真结果验证了所提方案的有效性。     

Obstacle avoidance control of redundant robots using variants of particle swarm optimization

Four variants of Particle Swarm Optimization (PSO) are proposed to solve the obstacle avoidance control problem of redundant robots. The study involved simulating the performance of a 5 degree-of-freedom (DOF) robot manipulator in an environment with static obstacle. The robot manipulator is required to move from one position to a desired goal position with minimum error while avoiding collision with obstacles in the workspace. The four variants of PSO are namely PSO-W, PSO-C, qPSO-W and qPSO-C where the latter two algorithms are hybrid version of the first two. The hybrid PSO is created by incorporating quadratic approximation operator (QA) alongside velocity update routine in updating particles' position. The computational results reveal that PSO-W yields better performance in terms of faster convergence and accuracy.     

A small three-way valve using particle excitation with piezoelectric transducers for hydraulic actuators

Abstract

Robots composed of hydraulic actuators have been utilized in various fields and at disaster sites. However, the hydraulic control system for multiple-degree-of-freedom mechanisms is large because such systems require many control components. The purpose of this research was to develop a small hydraulic flow control valve. This paper describes the fabrication and evaluation of a small three-way valve by particle excitation using a piezoelectric transducer. This valve consists of two transducers and can switch the inlet and outlet ports by applying an AC voltage of different driving frequencies to each transducer because each transducer has different resonant frequencies. The flow rate was controlled by applying a voltage to the piezoelectric transducer. We evaluated the vibration characteristics of the fabricated three-way valve. The vibration velocity exhibited peaks at 120 and 155 kHz for the inlet and outlet port, respectively, and that of each transducer increased with the applied voltage. Therefore, this three-way valve can switch the opening port by changing the driving frequencies and continuously controlling the flow rate. As a result, we have succeeded in driving the novel small three-way valve.     

Multiobjective clustering analysis using particle swarm optimization

Clustering is a significant data mining task which partitions datasets based on similarities among data. This technique plays a very important role in the rapidly growing field known as exploratory data analysis. A key difficulty of effective clustering is to define proper grouping criteria that reflect fundamentally different aspects of a good clustering solution such as compactness and separation of clusters. Moreover, in the conventional clustering algorithms only a single criterion is considered that may not conform to the diverse and complex shapes of the underlying clusters. In this study, partitional clustering is defined as a multiobjective optimization problem. The aim is to obtain well-separated, connected, and compact clusters and for this purpose, two objective functions have been defined based on the concepts of data connectivity and cohesion. These functions are the core of an efficient multiobjective particle swarm optimization algorithm, which has been devised for and applied to automatic grouping of large unlabeled datasets. A comprehensive experimental study is conducted and the obtained results are compared with the results of four other state-of-the-art clustering techniques. It is shown that the proposed algorithm can achieve the optimal number of clusters, is robust and outperforms, in most cases, the other methods on the selected benchmark datasets.     

基于QPSO算法的单阶段投资组合优化

投资组合优化问题是NP难解问题,通常的方法很难较好地接近全局最优.在经典微粒群算法(PSO)的基础上,研究了基于量子行为的微粒群算法(QPSO)的单阶段投资组合优化方法,具体介绍了依据目标函数如何利用QPSO算法去寻找最优投资组合.在具体应用中,为了提高算法的收敛性和稳定性对算法进行了改进.利用真实历史数据进行验证,结果表明在解决单阶段投资组合优化问题时,基于QPSO算法的投资组合优化的性能比PSO算法更加优越,且QPSO算法在投资组合优化领域具有很大的实际应用价值.     

Longitudinal control of an intelligent vehicle using particle swarm optimization based sliding mode control

This paper focuses on the design of longitudinal controller for an intelligent vehicle which was built at Asian Institute of Technology based on sliding mode control. The proposed controller uses particle swarm optimization (PSO) for optimal tuning of sliding surface and controller gain in the sliding mode controller (SMC). The longitudinal control is conducted via controlling of throttle value angle using PSO-based SMC on the simplified first-order linear model of the intelligent vehicle and controlling of brake force using fuzzy logic. In order to achieve the desired headway time, integration of throttle valve angle control and brake force control is required. To obtain the optimal parameters of SMC, two equations velocity updating and position updating are applied. Firstly, the performance of proposed controller is evaluated by using MATLAB simulation to compare with conventional PD controller. Finally, the experimental results show that the proposed PSO-based SMC can perform efficiently in longitudinal control of the intelligent vehicle.