六足机器人步态仿真与实验研究

针对各应用领域对具有复杂环境适应能力的行走机器人的需要越来越大的现状,从灵活性和稳定性入手设计仿生六足机器人,通过规划机器人的运动步态,分析多自由度在运动过程中的突出优点,并研究不同运动步态下各转动关节的转矩随时间的变化关系,将软件模拟和样机测试所得数据相互参照,对机器人的实际运动能力进行检测,验证仿生六足机器人结构的合理性和运动的可行性,为仿生六足机器人物理样机的进一步研制提供理论依据。     

一种两层复合式微驱动平台的运动分析

介绍了一种复合式的微驱动平台机构,采用几何理论方法对它进行了运动分析,建立了运动学方程。通过实例证明了其可行性。     

机器人运动学正解仿真研究

根据机器人运动学原理,以Visual Basic6．0为平台,开发AutoCAD2000应用程序,通过人机交互输入,建立机器人运动学模型,动态显示机器人运动过程,成功地实现机器人运动学仿真。并用对PUMA-560机器人的运动学求正解的实例加以验证。     

管道全位置焊接机器人结构设计与分析

针对长输油气管道焊接效率低、劳动强度大和焊接质量不稳定的问题,研制了一种管道全位置焊接机器人。根据野外施工特点,采用模块化设计方法,确定了焊接机器人结构,主要包括行走机构、焊炬调节机构和送丝系统三部分,并对其结构特点和工作原理进行了分析。根据机械模型建立了机器人的运动学方程,进行了仿真和试验研究,仿真结果表明：该机器人可以完成对应壁厚钢管的焊接,且焊接质量良好。     

局部闭链码垛机器人运动学分析及轨迹规划

采用D-H法得到局部闭链码垛机器人运动学正逆解,利用MATLAB绘制其可达工作空间。基于任务需求及生产现场布置方案,完成机器人弧线过渡路径规划。依据路径规划结果,以机器人在目标轨迹上运行周期时间最短为目标,选择正弦、多项式及修正梯形3种加速度运动规律进行优选。在此基础上,通过运动学逆解将操作空间轨迹规划映射到关节空间,得到机器人各关节在目标轨迹上的位移、速度和加速度时变关系。结果表明:在弧线过渡模式下,采用修正梯形运动规律能有效缩短运行周期。     

3-PTT型滑块式并联机床的PLC控制

为实现钢铁企业实现钢坯点修磨自动化开发了3-PTT型滑块式并联机床,该机床具有结构简单,易控制的特点,采用松下FP2可编程控制器进行对其进行控制,介绍该系统硬件配置以及编程方法,应用结果表明该系统编程容易,成本低,性能可靠.     

3-PRRP~((4r))三平移并联机构及运动学分析

设计构造了3-PRRP(4r)平移并联机构,分析了机构的结构特征以及自由度,求出了机构的位置正解和反解的解析式;在给定范围内,采用圆柱坐标搜索法搜索出机构动平台的运动工作空间.该并联机构结构简单、紧凑,适合应用于微动机器人、三维减振等领域.     

蠕动转向机构的设计与分析

拱泥机器人是一种能在水下泥土环境中按照规划轨迹完成攻打千斤洞作业的新型水下特种机器人,蠕动转向运动的实现是拱泥机器人设计中的一个重要环节.为了有效地实现拱泥机器人的转向运动,根据并联机器人机构结构综合理论,设计3自由度蠕动转向关节,该关节具有推进、跟进和转向3个功能,运动过程分为推进动作和跟进动作两个部分.分别针对两种动作的运动学逆问题进行详细分析,给出数学模型及其求解过程,并建立该关节的虚拟样机模型.利用MATLAB软件求解运动学逆问题,利用ADAMS软件求解运动学正问题,并对关节运动学正逆问题进行实例分析.仿真数据表明,该关节设计合理,数学模型正确,为拱泥机器人的运动学、动力学及优化设计研究打下了基础,并为控制系统的设计提供了理论依据.     

Face Stability Analysis of Circular Tunnels Driven by a Pressurized Shield

The aim of this paper is to determine the face collapse pressure of a circular tunnel driven by a pressurized shield. The analysis is performed in the framework of the kinematical approach of limit analysis theory. It is based on a translational three-dimensional multiblock failure mechanism. The present failure mechanism has a significant advantage with respect to the existing limit analysis mechanisms developed in the case of a frictional soil: it takes into account the entire circular tunnel face and not only an inscribed ellipse to this circular area. This was made possible by the use of a spatial discretization technique. Hence, the three-dimensional failure surface was generated “point by point” instead of simple use of existing standard geometric shapes such as cones or cylinders. The numerical results have shown that a multiblock mechanism composed of three blocks is a good compromise between computation time and results accuracy. The present method significantly improves the best available solutions of the collapse pressure given by other kinematical approaches. Design charts are given in the case of a frictional and cohesive soil for practical use in geotechnical engineering.     

Application of Exponential-Based Methods in Integrating the Constitutive Equations with Multicomponent Nonlinear Kinematic Hardening

The von-Mises plasticity model, in the small strain regime, along with a class of multicomponent nonlinear kinematic hardening rules is considered. The material is assumed to be stabilized after several load cycles and therefore, isotropic hardening will not be accounted for. Application of exponential-based methods in integrating plasticity equations is provided, which is based on defining an augmented stress vector and using exponential maps to solve a system of quasi-linear differential equations. The solutions obtained by this new technique give very accurate updated stress values that are consistent with the yield surface. The classical forward Euler method is reformulated in details and applied to the multicomponent form of the nonlinear kinematic hardening in order to provide a comparison for the suggested technique. Moreover, a consistent tangent operator for the exponential-based integration strategy and also for the classical forward Euler algorithm is presented. In order to show the robustness and performance of the proposed formulation, an extensive numerical investigation is carried out.