Modeling,tracking, vibration and balance control of an underactuated mobile manipulator (UMM)

This paper presents an underactuated mobile manipulator (UMM) and focuses on solving modeling, tracking, and vibration- and balance-control problems. Although the study has been directed at warehousing applications, the developed techniques are general and can be applied to other applications. The derivation of equations of motion of the UMM, disturbance analysis, and model validation are investigated to reveal the actual system dynamics. Additionally, a simple but effective strategy is also developed to solve the equilibrium point and balance problem. Based on the dynamic model, two control architectures are proposed: Model Predictive Control (MPC) and MPC+Proportional-Integral (PI) with integral actions, respectively, and they can also be applied to other robotic systems. Compared to other MPC-based control strategies, the proposed controllers require less effort to implement in practice. Finally, simulations, experiments, and robustness verification are conducted and discussed, and the results are satisfactory.     

高斯混合模型结合加权似然的目标跟踪算法

鉴于高斯混合模型对背景变化快时无法精确检测出目标和目标跟踪的适应性差等瑕疵，提出了基于加权似然跟踪器来改进高斯混合模型实现运动目标跟踪算法。主要引入了自适应高斯混合模型来实时检测运动目标，然后空间加权似然来进行视频中的目标定位，引入加权似然期望值来改进高斯混合模型处理视频中的多尺度、多角度变化的目标跟踪不精准问题。通过VOT 2014 dataset对比实验结果表明提出的基于加权似然跟踪（Weighted Likelihood Tracking，WLT）和改进高斯混合模型（Improved Gaussian Mixture Model，IGMM）的目标跟踪算法较传统高斯混合模型跟踪算法在跟踪的精度有较大提高。在应对多尺度、多角度变化的目标跟踪表现出了较大的优势。     

Generalised multivariable supertwisting algorithm

The purpose of this paper is to present an extension of the generalised supertwisting algorithm (STA) to the multivariable framework. We begin by introducing an algorithm that may be deemed as a linear, quasicontinuous, or discontinuous multivariable system, depending on the functions that define them. For the class represented by such an algorithm we prove the robust, Lyapunov stability of the origin and characterise the perturbations that preserve its stability. In particular, when its vector field is discontinuous or quasicontinuous our algorithm is endowed with finite‐time stability. Due to its resemblance to the scalar case, we denote such finite‐time stable systems as generalised multivariable STA. Furthermore, the class of finite‐time stable systems comprise the currently available versions of STAs. To finalise, by means of simulation examples, we show that our proposed finite‐time stable algorithms are well suited for signals online differentiation and highlight their dynamical traits.     

基于网络社交媒体的子话题检测技术综述

在当前多种平台崛起的互联网背景下，与传统媒体相比，网络社交媒体中的数据具有传递速度快、用户参与度高、内容覆盖全等特点，其中存在着人们关注并发布评论的众多话题，而一个话题的相关信息中可能存在更深层次、更细粒度的子话题，针对该问题进行基于网络社交媒体的子话题检测技术的研究，这是一个新兴且不断发展的研究领域。通过社交媒体获取话题及子话题信息并参与讨论，这一方式正全方位、深层次改变着人们的生活，但是该领域技术还不成熟，且相关研究在国内尚处于起步阶段。首先，简述网络社交媒体中子话题检测的发展背景和基本概念；其次，将子话题检测技术分为七大类，对每类方法均加以介绍、对比和总结；然后，将子话题检测方式分为在线检测和离线检测两种方式，并将这两种方式进行对比，列举通用技术及两种方式下的常用技术；最后，概括了该领域当前不足及未来发展趋势。     

Global stable tracking control of underactuated ships with input saturation

In this paper, tracking control of underactuated ship in the presence of input saturation is addressed. By dividing the tracking error dynamic system into a cascade of two subsystems, the torques in surge and yaw axes are designed separately using the backstepping technique. More specifically, we design the yaw axis torque in such a way that its corresponding subsystem is finite time stable, which makes it to be de-coupled from the second subsystem after a finite time. This enables us to design the torque in the surge axis independently. It is shown that the closed-loop system is stable and the mean-square tracking errors can be made arbitrarily small by choosing design parameters. Simulation results also verify the effectiveness of the proposed scheme.     

Improved direct inverse tracking control of a piezoelectric tube scanner for high-speed AFM imaging

For a piezoelectric tube scanner (PTS), this paper proposes an improved direct inverse tracking control algorithm and apply it to an atomic force microscope (AFM) to accomplish high-speed scanning tasks. That is, to enhance the high-speed tracking control performance of a PTS, an improved direct inverse rate-dependent Prandtl–Ishlinskii (P–I) model is firstly constructed, which includes a polynomial module to eliminate the structure nonlinearity. Based on the model, a practical feedforward control law is then designed to implement high-speed tracking control for a high-frequency trajectory with strong robustness, which presents the advantages of high-speed response, simple structure and convenient implementation. Subsequently, the designed feedforward law is combined with a feedback component, and the combined control strategy is employed in an AFM to accomplish fast imaging tasks. Numerous experimental results are then collected, which convincingly demonstrate the superior performance of the proposed practical model/control scheme.     

三明气象保障中心值班填报系统的设计与实现

为了简化三明市气象局保障中心值班员填报值班记录的过程,方便值班数据的查询和导出,推进三明市气象局的无纸化办公,减少纸质值班本的使用。本文根据值班内容需求使用易语言和MySQL数据库系统,设计开发了一套贴合保障中心值班流程的信息填报系统。通过不断测试和功能调整,该系统符合保障中心值班工作需求,并简化了工作流程。     

基于交互式多模型的弹道导弹跟踪

弹道导弹飞行主动段和自由段的运动学模型差别很大,在未准确知道导弹关机点时间先验信息前提下如何对弹道导弹主动段到自由段进行连续跟踪已成为目前亟待解决的问题.针对该问题,提出了一种实时交互多模型跟踪算法,根据弹道导弹主动段和自由段不同受力情况建立相应的跟踪模型.该算法包括两个滤波器:一个为对主动段跟踪效果比较好的CA-EK...     

高超声速飞行器自抗扰PID姿态控制

针对高超声速飞行器模型非线性、气动参数变化剧烈的特点,运用自抗扰技术中的跟踪微分器,设计了自抗扰PID控制器,实现了对高超声速飞行器俯仰通道的姿态控制。仿真结果表明,通过两个跟踪微分器构造的自抗扰PID控制器对于高超声速飞行器这样复杂的模型有很好的控制能力,并且有很好的滤波性能和鲁棒性。