基于能量转换的仿人机器人摆动腿落地改进阻抗控制方法

针对没有缓冲装置的双足仿人机器人在快速运动中摆动腿落地会对机器人身体稳定性带来影响的问题,结合阻抗控制的控制特点,从能量转换的角度进行分析,提出了基于能量转换的仿人机器人摆动腿落地改进阻抗控制方法。以阻抗控制方法为基础,通过对机器人摆动腿落地时末端速度以及落地后质心速度的分析,结合在摆动腿落地这一过程中能量的转换关系,对机器人摆动腿各关节的力进行控制,从而达到机器人摆动腿缓冲落地的目的。最后,将此方法应用于机器人Nao,实验证明,机器人摆动腿落地时与地面的瞬时作用力减小,达到了缓冲落地的效果,同时也起到了预先控制的作用。     

一种新的双足机器人模型设计与相关研究

针对双足机器人最简模型在行走过程中出现摆动腿足部擦地的问题,提出了一种通过摆动腿膝关节弯曲达到摆动腿缩短的新模型。当摆动腿开始摆动时,摆动腿膝关节弯曲锁定,摆动腿缩短;当摆动腿摆动到最大位置时,膝关节解锁,摆动腿伸直再锁定,此后摆动腿回摆,系统变为直腿模型。采用脚后跟冲击控制,在摆动腿落地前,拖后的支撑腿与地面接触处施加一指向髋关节的瞬时冲击力,冲击力可以减小摆动腿着地时能量的损耗,同时驱动被动机器人向前行走。设计了迭代学习控制算法,找到极限环与不动点,实现不同给定期望步长跟踪的冲击力的计算。仿真结果表明,迭代学习控制可以有效的实现不同期望步长的跟踪,可以很快的找到机器人系统的不动点,通过收敛的相平面,得到稳定的极限环,保证了机器人行走过程稳定。     

人形机器人动态行走误差调整方法的研究

介绍人形机器人稳定行走的相关理论及研究发展,针对关节非线性伺服控制、行走稳定性、摆动脚落地碰撞等关键问题进行了研究,解决了仿人稳定行走控制中步幅自动调整的问题,并进行了模糊控制器设计。     

基于虚拟黏弹性肌肉模型的仿人机器人不平整地面稳定行走

复杂未知环境下,仿人机器人在行走过程中难以获取精确的地面信息,导致规划的落脚点与实际落脚位置之间存在误差,这会对机器人的平衡造成严重的干扰.针对该问题,提出了模拟人体肌肉黏弹性的虚拟肌肉模型,并基于该模型设计了仿人机器人在不平整地面上的稳定行走控制方法.首先,从仿生角度出发,扩展传统肌肉模型,构建了具有伸缩功能的虚拟肌肉模型,并对其黏弹性进行了分析.然后,基于该模型,采用LQR(线性二次型调节器)方法设计了虚拟肌肉伸缩长度与伸缩力的控制方法.最后,基于足部力传感器信息反馈,将该模型应用于仿人机器人行走过程中抬脚高度的调节,使仿人机器人能够适应未知复杂环境中地面高度的突变,或在机器人传感器系统获取的地面信息与实际情况相差很大的情况下实现稳定行走.结果表明,该算法可以使仿人机器人在高度差为6 cm以内的不平整地面上实现1.8 km/h的稳定行走.基于BHR-6P平台的行走仿真验证了该算法的有效性.     

复杂环境下仿人机器人有效支撑区域的感知

当主流的仿人机器人都采ZMP(zero moment point)理论作为稳定行走的判据.实时ZMP点落在支撑足与地面接触形成的多边形支撑区域内是仿人机器人实现稳定步行的必要条件.因此实现仿人机器人在复杂现实环境中稳定行走,必须要求机器人足部感知系统提供足够丰富的地面环境信息,从而可以准确获取支撑区域的形状以实现基于实时ZMP点的稳定控制.文中将柔性阵列力传感器应用于仿人机器人足部感知系统,提出了获取仿人机器人支撑区域形状的方法,而且通过实验验证了其可行性.     

基于双臂摆动的仿人机器人偏摆力矩矫正方法

针对仿人机器人在步行时产生的绕ZMP(零力矩点)的偏摆力矩导致其失稳甚至摔倒的问题,提出了一种基于双臂摆动的偏摆力矩矫正方法.分析了偏摆力矩产生的原因及其对机器人步行稳定性的影响;根据仿人机器人的连杆模型和手臂摆动的单摆模型,推导出了双臂摆动力矩的表达式,结合双臂摆动的示意图阐述了利用双臂摆动力矩矫正偏摆力矩的原理;采用三次样条插值规划出双臂参数化的摆动角轨迹,再通过穷举法遍历摆动角参数使双臂摆动力矩满足偏摆力矩的矫正要求.仿真结果表明,该方法不仅能较好地矫正偏摆力矩,使机器人实现稳定的步行,而且能保证双臂的摆动角轨迹单调、平滑和周期性。     

仿人机器人上下楼梯稳定行走控制策略

提出了仿人机器人上下楼梯稳定行走控制策略.首先引入了虚拟零力矩点的概念,然后推导了上下楼梯稳定区域和稳定裕量的计算方法,如果ZMP点在稳定区域内,则采用基于ZMP在线调整控制方案,提高稳定性.如果FZMP点在稳定区域外,则采用基于FZMP调节控制策略,及时修正行走轨迹,使仿人机器人获得新的稳定区域,恢复稳定.仿真结果表明了该控制策略的正确可行.     

基于关键帧相似性的仿人机器人步态规划

为解决传统步态规划方法运算量大、运行时间长的问题,提出一种基于关键帧相似性的仿人机器人步态规划方法,通过对步态关键帧的相似性度量、髋关节的规划、零力矩点(ZMP)的实时校正,实现仿人机器人曲线行走步态的在线调整,调整后的步态能够较好地逼近实际ZMP曲线。实践结果表明,该方法在降低运算量的同时较好解决了仿人机器人的步态稳定及快速规划问题,并且可以减少步态选择不理想时的时间消耗。     

基于ZMP误差校正的仿人机器人步行控制

步行环境不理想、外力扰动等因素导致仿人机器人步行时ZMP出现误差,从而影响机器人的步行稳定性.由于机器人的各关节角度都对ZMP有影响,若只校正支撑腿的踝关节或髋关节等单个关节角度,则难以达到理想的步行控制效果,因此,本文综合考虑各关节角度对ZMP的影响,先通过模糊控制器基于ZMP误差给出机器人的质心位置增量,再利用二次规划方法和质心的雅可比矩阵求解出满足该质心位置增量的各关节角度校正量.仿真实验表明,本文方法较好地跟踪了期望ZMP,提高了步行稳定裕度,使仿人机器人实现了稳定的步行.     

基于虚拟模型的四足机器人对角小跑步态控制方法

为提高四足机器人对角小跑运动的稳定性,实现机器人躯干6维运动方向控制的解耦,提出了一种基于虚拟模型的对角小跑步态控制方法.控制器主要包括支撑相虚拟模型控制和摆动相虚拟模型控制.在支撑相,建立了作用于躯干质心的虚拟力与对角支撑腿关节扭矩之间的数学关系,通过调整躯干虚拟力的大小控制躯干的高度与姿态,控制机器人前进速度和自转角速度.在摆动相,将机器人侧向速度控制引入到足端轨迹规划中,并通过虚拟的"弹簧-阻尼"元件驱动摆动足沿给定轨迹运动.此外,在控制器设计过程中,引入了状态机,用于监控机器人各腿的状态,并输出对角小跑步态相位切换指令.仿真实验结果表明,机器人能够以对角小跑步态在平地上进行全方位移动,跨越不平坦地形,并能够抵抗外部冲击,证明了文中控制方法的有效性和鲁棒性.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.