Optimal location of process measurements

The problem of optimally locating a given number of Bensors for observing a general linear distributed parameter system is considered. Measurements at the sensors are assumed to be available continuously in time, and the design criterion is minimization of a scalar measure of the covariance of the estimate error in the optimal linear filter. Necessary conditions for optimality are derived based on the formulation of a distributed parameter matrix minimum principle. A computational algorithm is developed for determining the optimum set of measurement locations. The algorithm is applied to the problem of optimally locating temperature sensors in a solid undergoing transient heat conduction.     

Optimal state estimation using randomly delayed measurements without time stamping

This paper studies an optimal state estimation (Kalman filtering) problem under the assumption that output measurements are subject to random time delays caused by network transmissions without time stamping. We first propose a random time delay model which mimics many practical digital network systems. We then study the so‐called unbiased, uniformly bounded linear state estimators and show that the estimator structure is given based on the average of all received measurements at each time for different maximum time delays. The estimator gains can be derived by solving a set of recursive discrete‐time Riccati equations. The estimator is guaranteed to be optimal in the sense that it is unbiased with uniformly bounded estimation error covariance. A simulation example shows the effectiveness of the proposed algorithm. Copyright © 2013 John Wiley & Sons, Ltd.     

Asymptotic stabilization of the position of a rigid body with fixed point without velocity measurements

The problem of stabilization of a rigid body with a fixed point in reference to its velocity and position is considered. It is assumed that the rigid body is controlled by three external torques. The proposed controlling torques need neither the measurements of the velocity nor the information about the inertial parameters. Such a control may be realized by the on-line solution of the auxiliary differential equations.The stability of the closed loop nonlinear system is established by means of the Lyapunov function and Barbashin's theorem. The proposed control may be applied to stabilize the satellites controlled by the reactive jets.     

Almost global stabilization of fully-actuated rigid bodies

This paper addresses the problem of stabilizing a fully-actuated rigid body. The problem is formulated by considering the natural configuration space for rigid bodies, the Special Euclidean group SE(3). The proposed solution consists of a landmark-based controller for force and torque actuation that guarantees almost global asymptotic stability of the desired equilibrium point. As such the equilibrium point is asymptotically stable and only a nowhere dense set of measure zero lies outside its region of attraction. The controller uses velocity measurements and the position coordinates of a collection of landmarks fixed in the environment. As an additional feature, the control law is designed so as to verify prescribed bounds on the actuation.     

人体声发射定位技术的研究

从人体声发射技术与医学检测的特点出发,将人体骨科疾病的诊断和人体声发射结合起来,提出了具体的研究问题和解决手段。通过BL—420生物机能实验系统采集人体骨骼中的声发射信号,对该声发射信号利用互相关法计算时差,从而实现声源定位。     

Optimal exponential feedback stabilization of planar systems

This paper solves the problem of finding an optimal feedback control ensuring the maximal rate of convergence of system solutions to the origin for a general class of planar control systems including switched, bilinear systems and ones described by differential inclusions, etc. The prescribed control set is assumed to be compact but not necessarily convex. The developed approach is based on finding the minimal Lyapunov exponent of the system with an open loop control which provides an upper bound for the optimal convergence rate of the closed loop system. Then an optimal feedback controller is constructed for which the obtained bound is attained.     

Optimal controller location in wireless networked control systems

The control performance of wireless networked control systems (WNCS) has been shown to heavily depend on the packet delivery quality of both the sensor‐to‐controller and controller‐to‐actuator communications. Such quality relies on the relative distance between the wireless transmitter and receiver, which naturally raises the challenging problem of controller placement in WNCS for optimal control performance. In this paper, we investigate the optimal controller location (OCL) problem in WNCS based on linear‐quadratic‐Gaussian control strategy. For the one‐hop network case where the controller can only be placed at either the sensor side or the actuator side, we derive a simple yet effective criterion to determine the OCL. For the more general multi‐hop case where the controller can be located at either one of the sensors, relays, or actuators, we obtain the necessary and sufficient condition under which the closed‐loop system is guaranteed to be stable. On the basis of these results, we further transform the OCL problem into an optimization problem that can be solved efficiently. Numerical results are provided to verify our analysis. Copyright © 2013 John Wiley & Sons, Ltd.     

Optimal stabilization of linear systems via decentralized outputfeedback

Presents an approach to the optimal stabilization of a linear time-invariant system via decentralized control. The class of controllers considered does not restrict the controller to be finite dimensional or time invariant. In fact, the controller structure proposed can be regarded as a form of time varying sampled data control. The main result of the paper presents a scheme for constructing a collection of decentralized controllers which stabilizes the system and is optimal with respect to a quadratic performance index     

Optimal sensor location in the presence of nonstationary noise

Observability conditions for distributed parameter systems with nonstationary state excitation noise are derived. Because these conditions are violated in most cases of interest in process control an optimal projection approach and a sensor location criterion are developed to minimize the error caused by the lack of observability. The value of these concepts was demonstrated in real time experiments on a system with two spatial dimensions, the heating of a cylindrical ingot. It was found that through the nonstationary noise model and the optimal sensor location significantly improved state estimates can be obtained when persistent or slowly varying unmeasured disturbances affect the system. The real-time requirements for the filter were very modest and an application in the process industries where these disturbances always present a serious problem, seems entirely feasible.     

Limitations in remote stabilization over unreliable channels without acknowledgements

We consider the remote control of linear systems using unreliable communication channels where transmitted messages may be randomly lost and aim at clarifying the limitations arising there. In particular, we study the case without acknowledgement messages from the actuator to the remote controller regarding the arrival of the control input. It is shown that for a class of plants, stabilization is possible if and only if the loss rates satisfy critical bounds which have been known in the literature when acknowledgements are available. We present a constructive proof employing a nonlinear controller that makes control input estimation.     

Optimal sensor location for detecting changes in dynamical behavior

We address the problem of optimal sensor location for monitoring the eigenstructure of a multivariable dynamical system. The criterions which are optimized are the power of new tests designed for detecting and diagnosing changes in the eigencharacteristics of a system [3], [12]. The key points are the choice of the parameterization for computing the criterion and the comparison of designs with a different number of sensors. The discussion of the numerical results for sensor location includes the analysis of the effect of the geometry of the unknown excitation.     

电磁导引小车最小精确定位系统的研究

针对传统电磁导引很难实现精确定位和定位算法计算复杂度高的问题,提出了一种基于电磁导引的寻线行驶的小车,利用电流导轨外磁感应强度的差别进行导引定位的技术,依据毕奥-萨伐尔定律和独立提出的三维空间感应电动势的计算模型,对小车建立最小的精确定位系统的方法。此方法能对电磁导引小车建立最小精确定位系统,而且定位算法不复杂。通过实验证明此方法是可行的。     

Optimal stabilization of constant power loads with input LC-filters

This contribution examines fundamental performance limitations of active stabilization of constant power loads with input LC filters. In terms of the load input admittance, stabilization is posed as a linear H_∞ optimization problem, where the influence of stabilization on power control performance is minimized while meeting stability and robustness constraints. It is shown that the bandwidth of power control is upper limited by the resonance frequency of the input filter and that additional feedforward controllers can be used to individually shape reference tracking and disturbance rejection. Optimal results are verified through simulations using two different stabilization schemes.     

Optimal vibration control for nonlinear systems of tracked vehicle half-car suspensions

International Journal of Control, Automation and Systems - Technique of optimal vibration control and simulation for vehicle active suspension systems is developed. Considered the nonlinear damping...     

Preserving location privacy without exact locations in mobile services

Privacy preservation has recently received considerable attention in location-based services (LBSs). A large number of location cloaking algorithms have been proposed for protecting the location privacy of mobile users. However, most existing cloaking approaches assume that mobile users are trusted. And exact locations are required to protect location privacy, which is exactly the information mobile users want to hide. In this paper, we propose a p-anti-conspiration privacy model to anonymize over semi-honest users. Furthermore, two k*NNG-based cloaking algorithms, vk*NNCA and ek*NNCA, are proposed to protect location privacy without exact locations. The efficiency and effectiveness of the proposed algorithms are validated by a series of carefully designed experiments. The experimental results show that the price paid for location privacy protection without exact locations is small.     

Optimal measurements in phase estimation: simple examples

Quantum Information Processing - We identify optimal measurement strategies for phase estimation in different scenarios in which the interferometer acts on two-mode symmetric states. For pure...     

TerraSAR图像无控制定位精度研究

针对星载TerraSAR图像无地面控制点情况下的目标定位问题,在分析利用卫星星历数据的基础上,结合SAR距离模型和地球椭球模型,提出了一种TerraSAR图像的地面目标直接定位方法。通过杭州地区数据实验结果表明,TerraSAR图像在平均高程60m的丘陵地区,无控制距离向和方位向的定位精度中误差分别达到24.588m和12.265m。     

Optimal location and sizing of storage units in a drainage system

Adapting urban stormwater drainage systems is essential to handling increased urbanization and climate change. Within an urban area, storage units are an efficient solution to reduce peak runoff, but their implementation involves complex decisions. This paper presents a novel optimization model for defining, in existing sewer drainage systems, the number of storage units, their location, size and the orifice dimensions. The orifice is used to reduce storage unit outflow regulating downstream flows. These components allow an integrated flow control and flooding reduction throughout the network. The desired solution should offer the lowest cost and try to avoid any major flooding impact. The model includes hydraulic, flood and capacity constraints and it is solved through a simulated annealing algorithm that calls upon a dynamic rainfall-runoff simulator for complete evaluation of each solution. The performance of the optimization model is assessed through a case study inspired by a real urban sewer network.