Transfigured Loop Shaping Controller and its Application to Underwater Vehicle

A kind of transfigured loop shaping controller is presented in this paper. A transfigured loop shaping system puts a controller K in a feedback loop, while putting the dc gain of the controller K on the reference signal line. It is shown through frequency domain analysis and simulation that a transfigured controller can improve the dynamic behavior of a system. The transfigured loop shaping controller method is simple and effective and corresponds to the mixed sensitivity method of robust control theory, which improves the behavior of a system by iterative tuning of weighting functions. Satisfactory control results are obtained when it is applied to the design of an underwater vehicle. Keywords Loop shaping controller - underwater vehicle - transfiguration Zhang Xianku graduated from Beijing Institute of Clothing Technology, China, in 1990. He received the M. S. degree from Dalian Maritime University (DMU), China, in 1993 and the Ph.D. degree from DMU, in 1998. He is currently a professor at the Laboratory of Simulation and Control of Navigation Systems, Dalian Maritime University. His research interests include ship motion control and robust control.Jin Yicheng graduated from Zhejiang University, China, in 1967. He is currently a professor at the Laboratory of Simulation and Control of Navigation Systems, Dalian Maritime University. His research interests include simulating system of ship steering and visual control.

H_∞Loop Shaping Control for Plasma Vertical Position Instability on QUEST

QUEST has a divertor configuration with a high and a negative n-index, and the problem of plasma vertical position instability control in QUEST is still under extensive study for achieving high efficiency plasma. The instability we considered is that the toroidal plasma moves either up or down in the vacuum chamber until it meets the vessel wall and is extinguished. The actively controlled coils （HCU and HCL） outside the vacuum vessel are serially connected in feedback with a measurement of the plasma vertical position to provide stabilizing control. In this work, a robust controller is employed by using the loop synthesis method, and provides robust stability over a wide range of n-index. Moreover, the gain of the robust controller is lower than that of a typical proportional derivative （PD） controller in the operational frequency range; it indicates that the robust controller needs less power consumption than the PD controller does.

Loop-Shaping Based Control for Switch Mode DC-DC Power Converters

Renewable energy sources require switching regulators as an interface to a load with high efficiency, small size, proper output regulation, and fast transient response. Moreover, due to the nonlinear behavior and switching nature of DC-DC power electronic converters, there is a need for high-performance control strategies. This work summarized the dynamic behavior for the three basic switch-mode DC-DC power converters operating in continuous conduction mode, i.e. buck, boost, and buck-boost. A controller was designed using loop-shaping based on current-mode control that consists of two feedback loops. A high-gain compensator with wide bandwidth was used in the inner current loop for fast transient response. A proportional-integral controller was used in the outer voltage loop for regulation purposes. A procedure was proposed for the parameters of the controller that ensures closed-loop stability and output voltage regulation. The design-oriented analysis was applied to the three basic switch-mode DC-DC power converters. Experimental results were obtained for a switching regulator with a boost converter of 150 W, which exhibits non-minimum phase behavior. The performance of the controller was tested for voltage regulation by applying large load changes.

形状可调的Loop细分曲面渐进插值方法

针对Loop细分无法调整形状与不能插值的问题,提出了一种形状可调的Loop细分曲面渐进插值方法。首先给出了一个既能对细分网格顶点统一调整又便于引入权因子实现细分曲面形状可调的等价Loop细分模板。其次,通过渐进迭代调整初始控制网格顶点生成新网格,运用本文的两步Loop细分方法对新网格进行细分,得到插值于初始控制顶点的形状可调的Loop细分曲面。最后,证明了该方法的收敛性,并给出实例验证了该方法的有效性。

Noise behaviors of a closed-loop micro-electromechanical system capacitive accelerometer

The noise of closed loop micro-electromechanical systems(MEMS) capacitive accelerometer is treated as one of the significant performance specifications.Traditional optimization of noise performance often focuses on designing large capacitive sensitivity accelerometer and applying closed loop structure to shape total noise,but different noise sources in closed loop and their behaviors at low frequencies are seldom carefully studied,especially their behaviors with different electronic parameters.In this work,a thorough noise analysis is established focusing on the four noise sources transfer functions near 0 Hz with simplified electronic parameters in closed loop,and it is found that the total electronic noise equivalent acceleration varies differently at different frequency points,such that the noise spectrum shape at low frequencies can be altered from 1/f noise-like shape to flat spectrum shape.The bias instability changes as a consequence.With appropriate parameters settings,the 670 Hz resonant frequency accelerometer can reach resolution of 2.6 μg/(Hz)1/2 at 2 Hz and 6 μg bias instability,and 1300 Hz accelerometer can achieve 5μg/(Hz)1/2 at 2 Hz and 31 μg bias instability.Both accelerometers have flat spectrum profile from 2 Hz to 15 Hz.

尖牙反[牙合]矫治人字形和T形曲组合正畸弓丝矫治力建模

固定矫治技术是治疗牙齿反[牙合]最为有效的矫治手段,主要通过正畸弓丝释放的矫治力来达到反[牙合]矫治中的矫治空间预留、反[牙合]牙齿回收的目的。在牙齿反[牙合]畸形中,尖牙反[牙合]是最为常见的牙齿反[牙合]畸形,常使用人字形和T形组合曲关闭上颌牙列间隙。本文旨在正畸治疗前量化人字形和T形组合曲释放矫治力的情况,为正畸医师提供尖牙反[牙合]矫治的理论参考。分析人字形和T形组合曲的形变过程,将其形变过程分为弹性形变和弹塑性形变两类,并对两种形变下的矫治力微分方程进行了构建,将其释放的矫治力分为闭隙矫治力和倾覆矫治力两种,完成了人字形和T形组合曲理论模型的建立,其次对有限元仿真值与理论值的误差率进行计算,得到闭隙矫治力仿真值与理论值的误差率在0.43%~8.33%之间,倾覆矫治力的仿真值与理论值的误差率在2.13%~9.76%之间,搭建实验测量平台得到了闭隙矫治力实验值与理论值误差率为0%~9.30%、倾覆矫治力实验值与理论值的误差率为0%~9.76%,实验测量数据与理论值具有相同的非线性变化趋势,验证了人字形和T形组合曲理论预测模型的正确性,该模型能帮助医师在治疗前对正畸力进行详细的定量分析,从而为个性化治疗方案的制定提供依据,更好地满足患者需求。

Voltage Generation by Rotating an Arbitrary-Shaped Metal Loop around Arbitrary Axis in the Presence of an Axial Current Distribution

A thin metallic wire loop of arbitrary curvature is rotated with respect to an arbitrary axis of its plane. The device is excited by an electric dipole of infinite length and constant current. The resistance of the loop is computed rigorously as function of the position of the source. In this way, the induced voltage along the wire, under any kind of axial excitation, is given in the form of a superposition integral. The measured response is represented for various shapes of the coil, with respect to the time, the rotation angle and the position of the source. These diagrams lead to several technically applicable conclusions which are presented, discussed and justified.

Triple Notched Band Characteristics UWB Antenna Using C-Shaped Slots and Slot-Type Capacitively-Loaded Loop (CLL)

Ultra wide bands antennas with notched bands characteristics have recently been considered for efficient communication between devices. In this paper, a compact ultra-wideband antenna (UWB) for UWB applications with triple bandnotched characteristics is presented. The proposed antenna consists of a square patch with four truncated corners and a partial ground plane with a rectangular slit. The operation bandwidth of the designed antenna is from 2.66 GHz to more than 13.5 GHz. Band-notched characteristics of antenna to reject the frequency band of 3.18 - 3.59 GHz and 4.70 - 5.88 GHz, is realized by inserting two C-shaped slots in the patch, the third band of 9.54 - 12.22 GHz is achieved by slottype capacitively-loaded loop (CLL) inserted in the patch near the feed line. Details of the proposed antenna design and simulated results are presented and discussed.

基于非线性修饰和零阶保持器的船舶航向保持控制

[目的]为了解决船舶在海上航行时控制器舵角输出大、打舵频率高、控制速度较慢以及控制精度较低的问题,利用三阶闭环增益成形算法设计鲁棒控制器。[方法]首先,利用三阶闭环增益成形算法设计出线性鲁棒控制器,然后,在控制策略中加入双曲正切非线性修饰以及零阶保持器,在不同海况下对该控制器的性能进行仿真实验。[结果]仿真结果表明,相比于基于非线性修饰的传统PID控制器,在一般海况下,所提控制器在延迟时间、控制精度以及能量输出上分别改进了36%,14%和32%;在恶劣海况下,分别改进了27%,7%和16%。此外,不同海况下该控制器的仿真结果都具有稳定的舵角输出,并可以较快地稳定在临界值附近,证明了其具有较好的鲁棒性。[结论]改进的控制器符合工程实践,对于智能船舶的控制具有较好的应用参考价值。

Robust control of isopropyl benzene production process using H_(∞) loop shaping control scheme

This paper discusses robust control strategy for isopropyl benzene production process using the method of loop shaping H_(∞) technology.This cumene production process is a part of phenol plant in HOCL,Kochi.H_(∞) control of the propylene concentration is done here.The H_(∞) controller is derived from the linearised model of the reactor.The optimal H_(∞) controller is obtained by simplifying two algebraic Riccati equations.The proposed PID-like H_(∞) controller provides a single tuning parameter which makes the controller design more accurate.The proposed controller has been compared with other robust controllers like H_(2) and LQR.The H_(∞) controller is found to be superior in a wide frequency range and has a feature of low distortion and good regulating performance.The reactor model has been developed in COMSOL Multiphysics with the parameters obtained from HOCL plant,Kochi.The model extracted is reduced using model order reduction for the controller design.

一种基于双重非线性正反馈的节能降碳航向保持控制方法

[目的]为了解决船舶航向保持过程中舵角幅值过大以及舵角变换率过高而导致能耗过大的问题,提出一种基于双重非线性正反馈的节能降碳航向保持控制方法。[方法]采用闭环增益成形算法(CGSA)设计控制器,引入双重非线性反馈算法,通过双极性S函数与反正切函数的结合降低舵角幅值与操舵频率,最后使用正反馈的方法实现整个控制系统的控制。[结果]仿真结果表明,在6级海况和8级海况下,采用所提出的双重非线性反馈控制方法,反映舵机能耗的综合节能评价指标分别改进了31.53%和18.63%。[结论]验证了双重非线性反馈在降低舵机能耗、减少船舶航行过程中碳排放方面具有较好效果,以及正反馈和负反馈的等价控制效果。所提方法为船舶航向保持控制的研究提供了较好的应用参考价值。

海豚头气动外形导弹主动段过载驾驶仪设计

针对海豚头气动外形导弹主动段飞行过程中存在快速变化的俯仰干扰力矩导致驾驶仪过载指令不跟随的问题,研究了一种基于自适应控制的三回路过载驾驶仪在线调参方法。首先,对纵向短周期下的导弹动力学进行建模,建立三回路过载驾驶仪状态方程,在标称状态下采用极点配置对三回路过载驾驶仪的控制参数进行设计;其次,将标称状态下的驾驶仪视为参考模型,采用模型参考自适应方法,通过设计Lyapunov函数对自适应更新律进行设计。为了增强在建模不确定条件下自适应算法的稳定性,引入投影算子和死区的概念;最后,在气动拉偏条件下对海豚头气动外形导弹的主动段进行三回路自适应过载驾驶仪指令跟踪仿真。仿真结果表明,三回路自适应过载驾驶仪在海豚头气动外形导弹的主动段具有较好的动态跟踪特性。

基于仿生树形相变循环散热技术研究及变频空调应用

伴随环境温度升高,空调制冷量需求也会逐步增高,从而引发变功率模块发热严重,导致其内部芯片无法良好散热。通常采用压缩机降频工作方法保证电控板安全,但该方法的缺点是温度越高,空调制冷能力越差。针对该缺点,提出一种仿生树形的单向相变循环传热方法,开发了一款单向循环相变风冷散热器,通过焓差室测试,实现了散热器进风口温度62℃时,变频功率模块温度可以降低8℃以上,防止压缩机强制降频造成制冷量衰减。

冷轧带钢在线板形信号补偿技术及工业应用

综合考虑冷带钢轧机现场实际工况条件,根据板形仪在线板形检测原理、受力条件和几何关系,研究带钢横向温差、带钢卷形、边部覆盖,检测辊包角、挠度、安装几何误差和磨损量等因素对在线板形检测精度的影响,与生产实际相结合,建立一套满足工业应用的在线板形信号综合补偿模型。依托该模型开发的在线板形信号综合补偿技术,成功应用于鞍钢1 250 mm六辊冷带钢轧机上,使板形仪在线检测板形信号准确反映冷轧带钢真实板形状况,兼顾后续深加工工艺要求,根据不同轧制条件和产品规格制定动态板形标准曲线,为板形闭环控制提供可靠板形数据,显著提高冷轧带钢产品的板形指标和质量稳定性。总张力计算值与实测值误差在3%以内,板形闭环控制投入后,稳态时板形指标在6 I以内。

倒立摆系统的一种H_∞优化控制

在运用H∞环路成形设计方法时权函数的选择一般是凭经验试凑,不能保证所得控制器综合指标最优;且控制器阶次较高,不便于工程实现和参数调整.鉴于以上问题,提出了基于遗传算法的权函数选取方法,在遗传算法的目标函数里加入对鲁棒性能和时域性能指标的约束,从而得到使控制器综合性能指标最优的权函数,避免了凭经验试凑权函数的盲目性;然后,给出一种用多变量PID控制器逼近此控制器的方法,使所得控制器便于实际运用.最后用此方法对小车倒立摆系统进行仿真,结果表明了该方法的有效性.

H_∞回路成形设计的鲁棒性

回路成形法设计中是用互质因子摄动来表示系统不确定性的.文中对这种互质因子摄动进行了较详尽的分析,指出系统中的弱阻尼模态会增大互质因子摄动的范数,因而降低了允许的摄动值,使系统实际上失去了鲁棒性.所以H∞回路成形设计并不一定像所期望的那样具有鲁棒性.文中并用一个参数摄动下的鲁棒性为例来进行说明.

船舶航向保持的鲁棒神经网络控制

设计一个N5-5-5-5-5-5-1前向神经网络,经训练得到一个开环的船舶航向保持控制器,使其能够较好地保持典型输入信号作用下的船舶航向;然后应用闭环增益成形算法,形成闭环控制系统。这种基于神经网络的航向保持方案,将神经网络的适应能力、非线性函数映射能力和闭环增益成形算法的鲁棒性结合起来,改善了系统的鲁棒性能。这种方法设计过程简单,物理意义明显。

H_∞鲁棒控制理论发展的十年回顾

回顾了状态空间Ｈ∞鲁棒控制理论十年的发展历史。首先介绍了Ｈ∞鲁棒控制理论的概念及实质，然后将其发展过程划分为４个阶段，给出了国际著名学者的重要成果年代文献表，并归纳出Ｈ∞鲁棒控制理论的特点，简介了小增益理论、回路成形及μ分析的主要内容。

双环网络G(N;1,s)的L形瓦仿真算法

提出双环网络G(N;1,S)的L形瓦仿真算法,利用VB6.0作为编程语言、SQL Server2000作为数据库来实现这一算法,对任意给定N,而2=<S<=N-1的这样一族双环网络的L形瓦和参数都可以得出来。找出了该族双环网络L形瓦分布特点(由矩形逐渐变成典型的L形瓦)和直径的分布特点(具有最大值、最小值和中间对称性);对任意N,有不少s使得G(N;1,s)紧优。

漏斗型导流内构件对内循环三相流化床流体力学与传质特性的影响

The effects of funnel-shape internals on hydrodynamics and mass transfer in an internal loop three-phase fluidized bed were investigated.Three different kinds of internals were designed which were setup on the top of draft-tube in terms of horizontal angle and outer diameter, and gas hold up, liquid mixing time, liquid circulation velocity and mass transfer coefficient were measured respectively.It was shown that the riser gas holdup and mass transfer coefficient increased by 10% and 15% than that without such an internal, liquid mixing time decreased by 10% to 25%.When the superficial gas velocity was less than 0.5 cm·s-1, liquid circulation velocity increased with the setup of such internals·Liquid circulation velocity decreased when the superficial gas velocity was above 0.5 cm·s-1.In addition, the variation of structural parameters of funnel-shape internals had significant effects on hydrodynamics and mass transfer.