交互式信息终端与信息精准投放的可行性研究

目的通过交互式的信息终端,研究广告信息的精准投放。方法通过交互式信息终端上的高清摄像设备采集受众的面部信息,基于人脸识别技术对采集的信息进行分析,获得受众年龄、性别等基本信息,再配合信息投放的优选算法做到广告信息的有选择性精准投放。结果确定了它的基本模型与工作原理。结论以交互信息技术为支撑的信息传递模式必将取代目前的单向信息传递方式。     

Mechanics of peristaltic locomotion and role of anchoring

Limbless crawling is a fundamental form of biological locomotion adopted by a wide variety of species, including the amoeba, earthworm and snake. An interesting question from a biomechanics perspective is how limbless crawlers control their flexible bodies in order to realize directional migration. In this paper, we discuss the simple but instructive problem of peristalsis-like locomotion driven by elongation–contraction waves that propagate along the body axis, a process frequently observed in slender species such as the earthworm. We show that the basic equation describing this type of locomotion is a linear, one-dimensional diffusion equation with a time–space-dependent diffusion coefficient and a source term, both of which express the biological action that drives the locomotion. A perturbation analysis of the equation reveals that adequate control of friction with the substrate on which locomotion occurs is indispensable in order to translate the internal motion (propagation of the elongation–contraction wave) into directional migration. Both the locomotion speed and its direction (relative to the wave propagation) can be changed by the control of friction. The biological relevance of this mechanism is discussed.     

磁流变阻尼器简化力学模型研究

基于磁流变液体在不同磁场和剪切率下流变特性和磁流变阻尼器在混合模式下的力学原理,推导出包含四个待定系数的磁流变阻尼器简化力学模型。利用MTS8701系统测试的磁流变阻尼器的阻尼力与活塞杆运动速度及励磁电流的试验数据,对磁流变阻尼器简化力学模型进行了系数辩识。用磁流变阻尼器的电压驱动和电磁系统动态响应时间加上磁流变液体成链时间作为磁流变阻尼器的响应时间,建立了带时滞因子的磁流变阻尼器简化力学模型。试验与仿真分析结果表明,该简化力学模型能反映其基本力学特性。     

Biomimetic Locomotion of Electrically Powered “Janus” Soft Robots Using a Liquid Crystal Polymer

Oriented liquid crystal networks (LCNs) can undergo reversible shape change at the macroscopic scale upon an order–disorder phase transition of the mesogens. This property is explored for developing soft robots that can move under external stimuli, such as light in most studies. Herein, electrically driven soft robots capable of executing various types of biomimetic locomotion are reported. The soft robots are composed of a uniaxially oriented LCN strip, a laminated Kapton layer, and thin resistive wires embedded in between. Taking advantage of the combined attributes of the actuator, namely, easy processing, reprogrammability, and reversible shape shift between two 3D shapes at electric power on and off state, the concept of a “Janus” soft robot is demonstrated, which is built from a single piece of the material and has two parts undergoing opposite deformations simultaneously under a uniform stimulation. In addition to complex shape morphing such as the movement of oarfish and sophisticated devices like self‐locking grippers, electrically powered “Janus” soft robots can accomplish versatile locomotion modes, including crawling on flat surfaces through body arching up and straightening down, crawling inside tubes through body stretching and contraction, walking like four‐leg animals, and human‐like two‐leg walking while pushing a load forward.     

基于自适应模糊逻辑和神经网络的双足机器人控制研究

在双足机器人行走控制中,为了改善系统的行走性能,提出了一种基于RBF神经网络前馈控制的力矩补偿控制方法。该方法将自适应模糊控制和神经网络逆模控制有效地结合起来,利用神经网络来逼近系统的逆动力学模型,提高系统了的控制性能,改善了机器人的行走特性。     

Development of a compliant legged quadruped robot

This paper presents the detailed steps for design and development of a compliant legged fault tolerant quadruped robot where each leg has two links and two motorized revolute joints for locomotion. The body and upper links of legs are rigid whereas the lower link of each leg is compliant. Amble gait is demonstrated on the developed robot. Safety and reliability are the most critical issues for the quadruped robot. During the failure of any joint, performance of quadruped robot is affected. In this paper, locked joint failure is also discussed. Strategies for fault tolerant control of the quadruped are developed and experimentally validated. The developed robot can be used for various hardware-in-the-loop controller prototyping such as reconfiguration, fault tolerant control, and posture control, etc. pertaining to quadruped robots.     

Optimization of refrigeration system with gas-injected scroll compressor

Gas refrigerant injection has been proven as an effective method to improve the performance of the scroll compressor and its refrigeration system under high compression ratio working conditions. Much research on the injected scroll compressor and its system has been conducted, but the universal control and design method is still lacking. A model of the refrigeration system with a gas-injected scroll compressor is developed in this paper. With this model, the effects of gas injection on the system and component parameters are investigated. Based on the identified evaporator characteristics and thermodynamic analysis, a set of general principles for the design and operation of the refrigeration or heat pump system with a gas-injected scroll compressor is proposed.     

基于DBR系统的敏捷供应链协同机制

基于单一生产系统内部DBR生产计划与控制系统的实现机制,通过对其应用范围的进一步扩展,提出了供应链管理环境下DBR系统运作的六条基本原理,构建了供应链环境下DBR系统的基本框架,从计划、缓冲与控制机制三个方面对其实现机制进行了探讨.提出了支持DBR系统运作的供应链协同计划与控制模型,该模型基于单一节点企业内部DBR系统和供应链DBR系统的共同运作,通过面向订单对象的分布式生产控制模式和电子看板,实现供应链系统的协同计划与控制.     

一种基于静力位移测量值的车辐式屋盖结构索力识别方法

该文从车辐式张拉屋盖结构的组成特点出发,提出了一种基于静力位移测量值的索力识别方法。首先通过测量屋盖结构的几何位形,建立有限元模型。然后给真实结构施加特定荷载并测量加载点位移。给有限元模型施加同样的荷载并计算其位移。通过比较计算和实测的位移值,修正并迭代有限元模型中拉索的预应力;当计算位移与实测位移一致时就获得了拉索的真实内力。该方法只需要测量加载的自由度所对应的位移,能够在通用有限元软件ANSYS上进行索力识别,计算结果准确。     

基于ADAMS的助力机械腿结构设计与仿真

 为研究助力机械腿的步态周期,提出采用虚拟动力学软件仿真模型行走过程的方法.结合人体结构和行走规律,研究助力机械腿的工作原理和功能实现,对助力机械腿进行机械结构的设计,并建立助力机械腿和与之相配合的数字人的三维模型,利用ADAMS对人体行走步态进行仿真模拟控制.试验验证了建立的助力机械腿符合人体行走的要求,在技术上是可行的,为实体样机试验提供了参考,对研究助力机械腿控制算法具有积极意义.     

Frequency control technique applicable to either voltage- or current-feedback magnetically-coupled switching-transistor oscillators

Through the use of nonlinear circuit techniques similar to those normally associated with series-connected magnetic amplifiers, it is possible to modify the basic circuits of almost all of the numerous types of magnetically-coupled switching-transistor multivibrators so as to provide for frequency control of these circuits by means of a low-level dc control signal. Using two well-known types of such inverter circuits as examples, this paper describes the basic principles involved in this frequency control technique and discusses the operation of two test circuits. A primary advantage of this frequency control method is its physical simplicity and low cost.     

产品操作界面元素布局多目标优化设计

目的针对产品设计中操作界面布局设计时存在的随意性、不确定性大等问题,使用多目标优化设计的方法,寻找界面元素的最优布置,以提升界面的使用舒适性和人机交互效率。方法在分析了工效学准则和界面布局美度评价准则的基础上,确立了层次性、相关性、简洁性和舒适性四个界面布局基本原则,并依据原则构建了界面元素布局多目标优化数学模型,在此模型的基础上采用改进的遗传算法,建立基于遗传算法的界面元素布局多目标优化方法。结果给出产品操作界面布局设计的基本原则,提出一种基于遗传算法的产品操作界面元素布局的多目标优化方法及流程。结论提出的布局原则和优化方法能较好地协助设计师获得满足设计需求的布局方案,实例结果表明了理论模型的合理性与遗传算法对于界面元素布局多目标优化问题求解的有效性。     

基于N维云模型的客户共性与个体特征研究

依据所采集的客户服务属性数据和客户本体属性数据,运用多维正态云模型对客户群共性行为特征进行了描述,构建客户群数值特征矩阵。通过云相似性度量的方法,从质的层面上分析客户群之间的相似性,并依据相似度对客户群进行动态调整;确定各个客户群的标准型客户,运用多维X条件云发生器生成个体客户的特征属性值对客户群属性特征的激活强度,从量的层面上计算个体客户与客户群的标准型客户之间的差异。最后通过模拟分析,计算出客户群之间的相似度、个体与群体之间的差异值,证实运用多维云模型理论可以很好地进行客户行为分析。     

A collisional perspective on quadrupedal gait dynamics

The analysis of terrestrial locomotion over the past half century has focused largely on strategies of mechanical energy recovery used during walking and running. In contrast, we describe the underlying mechanics of legged locomotion as a collision-like interaction that redirects the centre of mass (CoM). We introduce the collision angle, determined by the angle between the CoM force and velocity vectors, and show by computing the collision fraction, a ratio of actual to potential collision, that the quadrupedal walk and gallop employ collision-reduction strategies while the trot permits greater collisions. We provide the first experimental evidence that a collision-based approach can differentiate quadrupedal gaits and quantify interspecific differences. Furthermore, we show that this approach explains the physical basis of a commonly used locomotion metric, the mechanical cost of transport. Collision angle and collision fraction provide a unifying analysis of legged locomotion which can be applied broadly across animal size, leg number and gait.     

二维保证下汽车维修备件动态库存控制策略

以汽车产品为例,针对失效率以时间或里程为计量单位的单位价值高、需求率低的不可修零部件,以未来销售预测为起点,依据二维保证政策的特点确定某时点处于保证时效内的汽车数量,基于产品可靠性对保证备件的需求进行预测,针对保证备件需求的特点,提出动态分段(Q,r)库存控制策略,通过案例验证了该库存策略可有效降低库存成本支出。     

基于多代理系统的微电网多目标优化调度

微电网在并网情况下的多目标稳定运行是微电网运营和建设的基本要求。从并网型微电网的经济目标和环保目标出发,建立微电网多目标优化模型,其中经济目标考虑分布式电源的燃料费用、运行维护费用、启停费用和与大电网的能量交互费用,环保目标考虑污染气体的排放量。提出一种基于多代理系统（multi-agent system,MAS）的分时电价机制下储能装置的调度策略,并且采用改进的NSGA-Ⅱ算法优化可控微源和储能装置的出力。以某地区微电网单元为例进行仿真,验证了所建模型和改进算法的有效性。试验结果表明,改进的NSGA-Ⅱ算法性能更优,所提出的策略可以控制储能装置一个周期内的充放电次数,延长使用寿命。     

Rate-dependent control strategies stabilize limb forces during human locomotion

A spring-mass model accurately predicts centre of mass dynamics for hopping and running animals and is pervasive throughout experimental and theoretical studies of legged locomotion. Given the neuromechanical complexity of the leg, it remains unclear how joint dynamics are selected to achieve such simple centre of mass movements consistently from step to step and across changing conditions. Human hopping is a tractable experimental model to study how net muscle moments, or joint torques, are coordinated for spring-mass dynamics, which include stable, or invariant, vertical ground forces. Subjects were equally able to stabilize vertical forces at all hopping frequencies (2.2, 2.8, 3.2 Hz) by selecting force-equivalent joint torque combinations. Using a hybrid-uncontrolled manifold permutation analysis, however, we discovered that force stabilization relies less on interjoint coordination at greater hopping frequencies and more on selection of appropriate ankle joint torques. We conclude that control strategies for selecting the joint torques that stabilize forces generated on the ground are adjusted to the rate of movement. Moreover, this indicates that legged locomotion may involve the differential regulation of several redundant motor control strategies that are accessed as needed to match changing environmental conditions.     

Microelastic imaging of bone

Several high-frequency ultrasound techniques have been developed during the last decade with the intention of assessing elastic properties of bone at the tissue level. The basic measurement principles can be divided into: 1) measurement of the compressional wave velocity in thin tissue sections; 2) measurement of surface acoustic wave velocities in thick sections; and 3) derivation of the acoustic impedance from the confocal reflection amplitude in thick sections. In this paper, the 3 principles are described with example measurements given in the frequency range from 50 MHz to 1.2 GHz. The measurements were made with 2 microscopes operating in the pulse-echo mode, either with frequencies up to 200 MHz and time-resolved detection or between 100 MHz and 2 GHz and amplitude detection. The methods are compared and their application potentials and limitations are discussed with respect to the hierarchical structure of cortical bone. Mapping of the confocal reflection amplitude has superior capabilities for deriving quantitative elastic and structural parameters in the heterogeneous bone material. Even at low frequencies (50 MHz), the mineralized tissue matrix can be separated from the larger pores (Haversian canals), and the elastic coefficient in the probing direction can be measured in 2 dimensions. Depending on the type of sample surface preparation (flat or cylindrically shaped), local distribution of a single elastic coefficient or the average transverse isotropic stiffness tensor can be derived. With frequencies in the GHz range, the lamellar bone structure can be analyzed. However, at one GHz, the acoustic wavelength is still one order of magnitude larger than the individual mineralized collagen fibrils. Although the thickness of a lamellar unit can easily be assessed from the acoustic image, the derivation of the anisotropic elastic properties of the mineralized collagen fibrils as well as the detailed structure of a lamella can only be accomplished with further model assumptions.