A Control Strategy for Terrain Adaptive Bipedal Locomotion

Rhythmic movements of a five-link sagittal biped with muscle-likeactuators are considered. In walking, as the support phases changecontact is periodically made with the environment. The inputs toevery actuator are modeled after the inputs to muscles in mammals. Thesystem possesses intrinsic position and velocity feedback due to theactuator dynamics. A control strategy is articulated that is novelin that it; a) is physiologically viable; b) simplifies the dynamics;and c) adapts to the speed of walking, going up and down stairs,going up or down inclines, maneuvering over obstacles or holes, andthe tempo and stride length of walking. Walking simulations of afive-link sagittal biped are presented.     

双足步行机器人的步态规划

主要研究了双足步行机器人的基本步态的建立过程,进行了参数化处理,提出了一种简单可行的步态规划方法,并对数据结果进行了仿真验证。仿真及试验结果表明,该文给出的方法能实现不同步速的连续动态步行。通过标准步态数据的建立,为实时步态规划校正和在线控制补偿算法奠定了基础。     

A SVM controller for the stable walking of biped robots based on small sample sizes

Conventional machine learning methods such as neural network (NN) uses empirical risk minimization (ERM) based on infinite samples, which is disadvantageous to the gait learning control based on small sample sizes for biped robots walking in unstructured, uncertain and dynamic environments. Aiming at the stable walking control problem in the dynamic environments for biped robots, this paper puts forward a method of gait control based on support vector machines (SVM), which provides a solution for the learning control issue based on small sample sizes. The SVM is equipped with a mixed kernel function for the gait learning. Using ankle trajectory and hip trajectory as inputs, and the corresponding trunk trajectory as outputs, the SVM is trained based on small sample sizes to learn the dynamic kinematics relationships between the legs and the trunk of the biped robots. Robustness of the gait control is enhanced, which is propitious to realize the stable biped walking, and the proposed method shows superior performance when compared to SVM with radial basis function (RBF) kernels and polynomial kernels, respectively. Simulation results demonstrate the superiority of the proposed methods.     

Gait flow image: A silhouette-based gait representation for human identification

In this paper, we propose a novel gait representation—gait flow image (GFI) for use in gait recognition. This representation will further improve recognition rates. The basis of GFI is the binary silhouette sequence. GFI is generated by using an optical flow field without constructing any model. The performance of the proposed representation was evaluated and compared with the other representations, such as gait energy image (GEI), experimentally on the USF data set. The USF data set is a public data set in which the image sequences were captured outdoors. The experimental results show that the proposed representation is efficient for human identification. The average recognition rate of GFI is better than that of the other representations in direct matching and dimensional reduction approaches. In the direct matching approach, GFI achieved an average identification rate 42.83%, which is better than GEI by 3.75%. In the dimensional reduction approach, GFI achieved an average identification rate 43.08%, which is better than GEI by 1.5%. The experimental result showed that GFI is stronger in resisting the difference of the carrying condition compared with other gait representations.     

SFN系统中OFDM频率同步新方法

由于SFN信道的强回波特性，SFN系统中的DVB-T OFDM接收机需要更为精确的频率同步保证信号的正确解调。本文在SFN系统中，提出一种OFDM频域全导频频偏估计算法，该算法基于符号中的全导频（包括连续导频和散布导频）估计整偏和细小偏；同时给出了频域小环校正整偏的结构，理论分析和仿真结果说明，该算法较传统的连续导频频偏估计算法提高了估计精度，更适合强回波的SFN信道,提出的整偏小环校正结构加快了频率同步的收敛速度。     

一种新的汽车牌照快速定位方法

选取具有很强稳定性和可识别性的车牌纹理特征，提出了一种快速的汽车牌照定位方法。该方法首先利用车牌的粗纹理特征，通过高通能量滤波进行初步定位；再基于细纹理特征，通过提取候选区域小波纹理信息结合数学形态学和投影法进行准确定位；最后跟据车牌的颜色和纹理均匀性对定位结果进行修正。实验结果表明该方法分割定位迅速，定位准确率高。     

一种自然纹理图像生成的新方法

提出了一种新的自然纹理图像生成方法 ,对传统的纹理图像统计模型和结构模型进行了改进 ,能够用来模拟和生成多种自然景物的纹理图像 .实验结果证明 ,该方法能有效地产生具有真实感的自然纹理图像     

Locomotion control of a four-legged robot embedding real-time reasoning in the force distribution

This paper discusses the application of rule-based reasoning to manage in real time the force distribution computation within a locomotion control of quadruped robots. The control uses input–output linearization in the attitude subsystem, and optimal linear control in the overall locomotion system. The force distribution approach provides more adaptability and flexibility to the locomotion control, because the system is capable of fast adaptation to a wide variety of situations. Rules defining the knowledge about how to deal with walk events and feet forces calculation are presented. The rule-based reasoning is made using the system (LAAS).     

一种提高双足机器人机动性的步行模式规划方法

为提高双足机器人的机动性以适应更宽更广的应用领域,提出一种在线规划方法.该方法根据最新的控制命令生成足迹,然后利用动力学方程的解析解在线同步规划质心(CoG)轨迹和零力矩点(ZMP)轨迹,并基于离散化算法解决机器人速度改变较大时局部ZMP轨迹的扰动问题,使其符合稳定性判据.该方法可使机器人在行走过程中一步实现任意的足迹改变,具有很高的机动性,经过在实体机器人Nao上进行效果验证并取得预期结果.     

Neuro-fuzzy gait synthesis with reinforcement learning for a biped walking robot

 A reinforcement learning-based neuro-fuzzy gait synthesizer, which is based on the GARIC (Generalized Approximate Reasoning for Intelligent Control) architecture, is proposed for the problem of biped dynamic balance. We modify the GARIC architecture to enable it to generate the trunk trajectory in both sagittal and frontal plane. The proposed gait synthesizer is trained by reinforcement learning that uses a multi-valued scalar signal to evaluate the degrees of failure or success for the biped locomotion by means of the ZMP (Zero Moment Point). It can form the initial dynamic balancing gait from linguistic rules, which are obtained from human intuitive balancing knowledge and biomechanics studies, and accumulate dynamic balancing knowledge through reinforcement learning, and thus constantly improve its gait during walking. The feasibility of the proposed method is verified through a 5-link biped robot simulation.     

Novel decentralized adaptive strategies for the synchronization of complex networks

This paper is concerned with the analysis of the synchronization of networks of nonlinear oscillators through an innovative local adaptive approach. In particular, time-varying feedback coupling gains are considered, whose gradient is a function of the local synchronization error over each edge in the network. It is shown that, under appropriate conditions, the strategy is indeed successful in guaranteeing the achievement of a common synchronous evolution for all oscillators in the network. The theoretical derivation is complemented by its validation on a set of representative examples.     

A Novel Navigation Method for Autonomous Mobile Vehicles

This paper presents a novel navigation method for Autonomous Mobile Vehicle in unknown environments. The proposed navigator consists of an Obstacle Avoider (OA), a Goal Seeker (GS), a Navigation Supervisor (NS) and an Environment Evaluator (EE). The fuzzy actions inferred by the OA and the GS are weighted by the NS using the local and global environmental information and fused through fuzzy set operation to produce a command action, from which the final crisp action is determined by defuzzification. The EE tunes the supports of the fuzzy sets for the OA and the NS; therefore, the capability of the navigation method is enhanced. Simulation shows that the navigator is able to perform successful navigation task in various unknown or partially known environments, and it has satisfactory ability in tackling moving obstacles. More importantly, it has smooth action and exceptionally good robustness to sensor noise.     

一种人体步态轨迹测量方法

为研究人体的步态运动规律,采用基于拉线传感器检测系统和人体关节角度测量装置,对人在不同路况下行走时踝关节运动轨迹和下肢关节角度进行了测量,根据人体下肢刚体模型和数据融合方法对测量结果进行了分析和处理,得到了人在上楼梯、平地行走和下楼梯时的步态轨迹和3种路况下的支撑相;上楼梯时的支撑相最大,平地行走次之,下楼梯最小.测量结果为了解人体运动规律和康复治疗提供了依据.     

异步电动机定、转子电阻参数在线实时估计方法

给出了一种异步电动机定、转子电阻参数在线实时估计方法,并将其应用于电压控制型转差频率矢量控制系统,计算机仿真结果表明该方法具有较好的参数估计效果。     

一种实时事务并发控制的新方法:SMVCC

提出了新颖的实时数据库事务并发控制方法：语义多版本并发控制协议（SMVCC）。利用实时数据库中存在多版本数据的特点,考虑实时数据和实时事务语义,结合实时数据库相似性概念,对传统多版本并发控制方法进行扩展,对不同事务采用不同并发控制策略,提高了事务并发度。     

网络化控制系统中新型控制方法的研究

网络化控制系统的出现,正成为新的热点,减少网络带宽的占用,是网络化控制系统的研究中一个十分令人关注的问题,探讨了如何减少在传感器和控制器之间,减少状态数据包传输的方法。设计了一个能使系统稳定的新型结构的控制器和一个特殊的网络传输规则。     

实现分布式仿真系统同步的一种方法

分布式仿真系统的构建过程中,关于各仿真子节点的协调运行与同步问题是其中的重点和难点。该文介绍了面向对象的实时仿真软件开发环境Constellation和网络传输服务NDDS这两个工具,并且结合这它们的特点和相互之间的密切联系,研究出一种应用它们实现分布式仿真系统同步的方法。最后建立一个卫星姿态控制仿真系统,介绍了如何实现这种方法,并且进行以下验证：在Constellation下和在Matlab下建立的仿真系统进行比较,验证系统和集中式系统仿真结果比较,验证系统在Windows操作系统下和实时操作系统下仿真结果比较。     

一种基于J2EE的异构数据库的同步方法

随着信息化发展和网络与计算机技术的广泛应用,企业或者部门间信息互通共享重要性,文章提出了一种基于J2EE的异构数据库间实现数据同步的方法,该方法在运用数据库触发器的基础上,运用java语言编写同步逻辑脚本,并将同步技术成功应用于某企业ORACLE与SQL Server数据库数据同步中。     

一种新的混合有源滤波器控制方法

针对混合有源滤波器HAPF的传统控制方法中存在的不足,提出了一种基于离散滑模控制算法的电流跟踪控制方法,避免了传统控制原理中系统滤波能力与稳定性之间的矛盾,不仅系统响应迅速,而且具有满意的控制精度,易于实现数字控制,仿真结果说明新的控制方法是行之有效的。