海洋机器人的闭环控制与流体动力学模型

本文给出一开启式海洋机器人的水平面运动与垂直面运动的流体动力学模型,闭环控制,解耦设计和仿真结果。本文对海洋机器人控制系统设计,有一定参考价值。

高阶无静差采样控制系统的动态综合

本文利用“最小响应法”给出了 N≥2阶无静差采样控制系统的设计公式.作者指出:对于某类闭环控制系统,在给定阶跃响应最大超调量σ_(max)的条件下,可以找出最佳比值T/T_(T 为系统的采样周期,T_(?)为对象的不便克服的等效小时间常数之和),使系统获得相应阶最大误差系数 K_(N+1),从而可使系统达到快速精密的控制指标。为了在工程设计中应用方便,文中还给出了二至六阶无静差的σ_(max),T/T_(?),K_(N+1)T(?)最佳参数组,使得这类闭环控制系统的设计最佳化和简易化.

Design and control of an ultraprecision stage used in grating tiling

In petawatt laser system, the gratings used to compose pulse compressor are very large in size which can be only acquired currently by arraying small aperture gratings to form a large one instead, an approach referred to as grating tiling. Theory and experiments have demonstrated that the coherent addition of multiple small gratings to form a larger grating is viable, the key technology of which is to control the relative position and orientation of each grating with high precision. According to the main factors that affect the performance of the grating tiling, a 5-DOF ultraprecision stage is developed for the grating tiling experiment. The mechanism is formed by serial structures. The motion of the mechanism is guided by flexure hinges and driven by piezoelectric actuators and the movement resolution of which can achieve nanometer level. To keep the stability of the mechanism, capacitive position sensors with nanometer accuracy are fixed on it to provide feedback signals with which to realize closed-loop control, thus the positioning precision of the mechanism is within several nanometers range through voltage control and digital PID algorithm. Results of experiments indicate that the performance of the mechanism can meet the requirement of precision for grating tiling.}

CSRe团簇内靶温度闭环控制器设计；Design of Closed Loop Temperature Controller for CSRe Internal Target System

介绍了国家重大科学工程项目——兰州重离子加速器冷却存储环(HIRFL-CSR)的实验环(CSRe)团簇内靶温度闭环控制器的设计。该控制器给气体喷嘴处测温电阻提供长时间稳定度为0.1%的1mA恒定电流,通过12位ADC得到喷嘴温度,并通过混合信号处理器MSP430F149来实现制冷/加热闭环操作。在多种不同实验气体的情况下,该控制器的温度控制精度小于0.5K。目前,该控制器在现场工作良好。

电子束蒸发镀膜速率控制

介绍了电子束蒸发镀膜速率控制的基本原理和方法,选取实际生产中大量使用且蒸发特性较难控制的SiO_2和HfO_2,对两者的电子束蒸发速率控制分别进行了实验研究。采用比例积分微分(PID)闭环反馈控制,通过Ziegler-Nichols工程经验公式进行原始参量整定,并在实验的基础上对控制器的原始参量进行调整以及对积分作用和微分作用进行分区处理,速率控制的实验结果表明,采用该参量整定方法并结合工艺流程的改进,能获得良好的速率控制。针对速率控制中存在的难点问题进行了分析,并提出改进措施:将速率控制和电子枪扫描控制相结合能进一步改善速率控制。

基于ARM的智能型定氮仪的研制

通过对凯氏定氮法和整个系统控制原理的分析,介绍了一种基于ARM的测定物质中氮元素含量的系统,该系统采用ARM微控制器LPC2214作为整个系统的控制核心,通过步进电机驱动进行标准溶液的滴定和光电检测确定滴定终点,形成闭环系统,实现了准确测定物质中氮元素的含量。文中给出了系统软硬件设计方案,对其实现方法及关键技术进行了研究。实验结果表明:该系统工作稳定,测量数据准确,具有一定的应用价值。

平面自由运动半物理仿真系统的初始条件实现

提出了一种平面自由运动半物理仿真系统的设计,对系统仿真试验的初始条件形成过程进行了具体阐述。系统中应用了一种平面两自由度直角坐标运动装置,用于完成系统驱动及速度和位置控制,同时这种运动装置能够进行直角坐标跟随运动,并与其末端测量机构共同实现对平面自由运动物体的高精度大范围位姿测量。建立了系统的运动学模型,并设计相应的控制算法实现试验所需的运动过程,采用半闭环和闭环相结合的方法有效控制系统的末端累积误差;针对提出的复合测量方法,建立了测量原理的数学模型,并进行了精度分析和仿真计算。实验证明这种设计和相应的控制测量方法合理可行。

基于模糊神经网络水下机器人直接自适应控制

提出了基于广义动态模糊神经网络的水下机器人直接自适戍控制方法,该控制方法既不需要预先知道模糊神经结构,也不需要预先的训练阶段,完全通过在线自适应学习算法构建水下机器人的逆动力学模型.首先,本文提出了基于这种网络结构的水下机器人直接自适应控制器,然后,利用Lyapunov稳定理论,证明了基于该控制器的水下机器人控制系统闭环稳定性,最后,采用某水下机器人模型仿真验证了该控制方法的有效性。

基于神经网络的激光熔覆高度预测

激光成形过程中,对熔覆高度进行实时检测,从而实现熔覆高度闭环控制是成形高质量零件的保证。激光成形过程是一个多参数耦合的非线性过程,大量激光参数对成形熔覆表面质量具有重要影响。在分析激光参数对熔覆高度影响的基础上,建立利用激光工艺参数预测熔覆高度的误差反向传播(Backpropagation,BP)神经网络模型,完成了网络算法设计。通过激光成形试验采集样本,利用训练样本对所建立的网络进行训练,完成网络输入输出高度映射关系,并利用测试样本对所训练的网络进行检验。仿真试验表明,神经网络熔覆高度预测模型具有很高的精度,验证了该预测模型在理论和实践上的可行性与有效性。神经网络熔覆高度预测模型为实现激光加工过程熔覆高度实时预测与闭环控制打下基础,对提高成形产品质量具有重要意义。

Robust Guaranteed Cost Control for Yaw Control of Helicopter

针对具有时变不确定性且不确定性界为椭球的线性系统提出了一种新的具有自适应机制的鲁棒保性能控制器设计方法。首先,引入一个具有可由自适应律在线调整的可调参数的目标模型,通过该参数来保证由目标模型与被控模型所获得的误差系统渐近稳定。结合保证目标模型稳定性的设计,最终形成保证闭环系统稳定且控制器增益仿射依赖于可调参数的鲁棒保性能跟踪控制器。应用于安装在试验平台上的小型直升机航向控制中,仿真试验表明了该方法的有效性。

Phase control of cross-phase modulation with electromagnetically induced transparency

We investigate a four-level double-Lambda atomic scheme interacting with four laser fields, a weak probe field, a weak signal field and two driven fields, in a closed-loop configuration. We study the Kerr nonlinearity associated with cross-phase modulation based on electromagnetically induced transparency. Our results show, in this closed-loop system, that the strength of cross-phase modulation and two-photon absorption are dependent critically on the relative phase between the excitation paths. By choosing the parameters appropriately, large cross-phase modulation can be achieved within a wide transparency window, while two-photon absorption is cancelled completely. The strength of cross-phase modulation can be enhanced much more by decreasing the intensities of two driven fields.

Phase-sensitive atom localization in a loop Lambda-system

The behaviour of the Lambda-system has been studied theoretically in the context of atom localization. In addition to the probe field and the standing wave driving field, a microwave field is introduced to couple the two lower states, and as a result our Lambda-system forms a closed loop. Therefore phase-sensitive atom localization is expected. Indeed by appropriate choice of the relative phase between three fields, an improvement by a factor of 2 has been found in the detection probability of atoms within the sub-wavelength domain of the standing wave. The effect of other parameters is also investigated.

Diassociativity in Conjugacy Closed Loops

Let Q be a conjugacy closed loop, and N(Q) its nucleus. Then Z(N(Q)) contains all associators of elements of Q. If in addition Q is diassociative (i.e., an extra loop), then all these associators have order 2. If Q is power-associative and |Q| is finite and relatively prime to 6, then Q is a group. If Q is a finite non-associative extra loop, then 16 ∣ |Q|.

Processing network models of energy/environment systems

Processing networks are a variant of the standard linear programming network model which are especially useful for optimizing industrial energy/environment systems. Modelling advantages include an intuitive diagrammatic representation and the ability to incorporate all forms of energy and pollutants in a single integrated linear network model. Added advantages include increased speed of solution and algorithms supporting formulation. The paper explores their use in modelling the energy and pollution control systems in large industrial plants. The pollution control options in an ethylene production plant are analyzed as an example. PROFLOW, a computer tool for the formulation, analysis, and solution of processing network models, is introduced.

Set invariance in control

The properties of positively invariant sets are involved in many different problems in control theory, such as constrained control, robustness analysis, synthesis and optimization. In this paper we provide an overview of the literature concerning positively invariant sets and their application to the analysis and synthesis of control systems.