Inverse kinematics of spherical wrist robot arms: Analysis and simulation

The spherical wrist robot arm is the most common type of industrial robot. This paper presents an efficient analytical computation procedure of its inverse kinematics. It is based on the decomposition of the inverse kinematic problem to two less complex problems; one concerns the robot arm basic structure and the other concerns its hand. The proposed computation procedure is used to obtain the inverse kinematic position models of two robot arms: one contains only revolute joints and the other contains both revolute and prismatic joints. The 1st and 2nd time derivatives of the obtained models give more accurate inverse kinematic velocity and acceleration models than numerical differentiation. These models are verified by simulation for two different trajectories. The obtained results demonstrate the effect of the proposed procedure on reducing the necessary computation time compared to other computation techniques.     

Inverse kinematics of a mobile robot

The problem of kinematics is to describe the motion of the robotic system without consideration of the forces and torques causing the motion. This paper presents two methods to obtain the inverse kinematics of a mobile robot. In the first method, two rows of the forward kinematics are selected, the inverse of these two rows is obtained, and later the inverse matrix is combined with the third row of the forward kinematics. In the second method, the pseudo-inverse matrix of the forward kinematics matrix is obtained. The comparison result of the two proposed methods is presented. Two simulations show the effectiveness of the proposed inverse kinematics algorithm.     

基于神经网络的机器人的逆运动学分析

文章提出了基于BP神经网络算法的机器人逆运动学的求解方法,给出了基于神经网络的机器人逆运动学求解的具体步骤和设计神经网络的相关注意事项.通过时KLD-600六自由度机器人仿真表明该算法简单可靠.     

二足机器人之动态平衡研究

主要探讨二足机器人（biped robots）行走或受到外力干扰时,通过动态平衡控制使机器人行走更趋稳定,并增强站立时稳定性．二足机器人动态平衡之实现,主要是将动态平衡控制程序撰写于Nios Ⅱ发展环境中,当二足机器人行走时,利用脚底压力传感器取得压力值,运算及判断二足机器人实际重心是否落在二足机器人支撑多边形范嗣内,并计算实际重心与期望重心之误差,以模糊控制器将二足机器人重心控制于支撑多边形范围内,使二足机器人行走时能够更加稳定,实验结果表明该方法是有效的．     

Computer simulation and dynamic modeling of a quadrupedal pronking gait robot with SLIP model

In this study, a quadrupedal pronking gait robot modeling was carried out with Spring Loaded Inverted Pendulum model in stance phase. This is achieved by solving a natural problem in which the main goal is to enable the robot to walk and run in a stable condition regardless of the environmental conditions. In order to solve this problem, dynamic model and control of a quadrupedal robot were realized for a pronking gait. The stance and flight phase dynamic structures were solved in a sequential closed loop to obtain the equation of motion for pronking gait. Spring Loaded Inverted Pendulum model was used as a dynamic model to simplify the simulation, dynamic locomotion and experimental works of the system, and also to simplify the pronking gait concept. The quadrupedal robot with pronking gait was controlled by proportional-derivative control algorithm. As a result, all computer simulations have shown that the proposed control actions and methods are more effective and make the system control quite easy and successful.     

Development of a robot control test platform

The development of a sophisticated robot experimental test-bed is described. A CRS Robotics Corporation A460 robot is de-engineered to add joint torque control and a Windows-based user interface so that advanced model-based robot controls can be tested. With this interface, experiment set-up, execution, data collection and display are selected with a mouse with point and click commands     

发电系统动态仿真监控平台研究

为了同步实时获取电力系统动态仿真数据以实现交互式仿真,使用LabVIEW软件及其数据记录和监控模块设计了一套监控平台,并利用MATLAB/Simulink软件进行了验证。构建了三相同步发电机带负载仿真模型,可通过程序控制断路器接入两种负载产生不同工况,支持现场对发电机电气参数进行连续监测,利用过程控制对象连接与嵌入OPC技术将测量值传递到虚拟仪器监控系统中实时显示各监测对象当前值和趋势图,同时实现了数据采集与存储、与模型控制交互等关键功能。实验结果表明,监控平台能正确地监控仿真模型的运行,并执行所设计的各项功能。     

Kinematic and dynamic analysis of a hexapod walking-running-bounding gaits robot and control actions

Kinematic and dynamic analysis, and control actions of a hexapod robot were realized for walking, running and bounding gaits in this study. If biological inspiration can be used to build robots that deal robustly with complex environments, it should be possible to demonstrate that legged biorobots can function in natural environments. Firstly, we tried to report on theoretic work with a six legged robot designed to emulate spider behavior like walking, running and bounding. We demonstrated theoretically that it can successfully walk, run and bound like a spider over natural terrain. Secondly, limitations in its capability were evaluated, and many biologically based important improvements were obtained for future experimental work. Thirdly, the hexapod robot with bounding gait was controlled by proportional-derivative control algorithm and was carried out by using spring loaded inverted pendulum model. Consequently, the developed kinematic and dynamic methods, and control action method makes both the system control easy and the system performance is improved by decreasing the run time for each loop.     

Computer graphics as an aid to a robot dynamical simulation analysis

This paper describes the results of an attempt to outline a computer graphic system that permits the generation and spatial transformations of polyhedric solids. This system was created to provide a simulator with enough visual resources to clearly represent the dynamical behavior of a robot mechanical system submitted to some control procedures. It has been adapted to a system with limited graphical resources. Considerations of other applications for this graphical feature are also outlined.     

动态系统安全性分析软件平台研究

装备系统的动态行为特征使其安全性分析工作复杂而困难.为满足装备系统动态安全性分析工程实际的需要,需开发集成化的软件平台并综合运用有关技术方法来进行.研究了动态系统安全性分析的主要工作内容,分析了动态系统安全性分析平台对基础数据、知识和模型的需求,提出了平台的结构和功能设计方案,并给出了分析流程.     

仿蟹机器人步态分析与仿真

在仿蟹机器人的行走控制中,步态的选择对机器人的稳定快速行走具有至关重要的作用。本文对仿蟹八足机器人的基本步态进行了分类,并进一步对八足波形步态进行分析,得出八足步行机器人在采用双四足步态的行走方式时,既可以满足速度的要求,又可以保证机器人的稳定性。通过计算机软件ADAMS对所选步态进行全局仿真,结果验证了步态规划的合理性,同时得到了机器人相关物理量的变化曲线,为进一步选择电机,分析机器人系统的动态特性提供了依据。     

绳索牵引康复机器人控制及仿真研究

康复机器人是典型的人机合作系统.人与机器人在同一物理空间,因此对机器人的柔顺性、安全性提出了严格要求.绳索驱动具有柔顺性好、占空间小、重量轻等特点,不会与人体产生刚性碰撞、冲击,非常适合于康复机器人的驱动控制.由于绳索的柔性使其只能承受拉力,其牵引构成冗余驱动系统,因此绳索位置伺服系统须引入力控制,保证工作时绳索具有一定的张力.针对康复训练机器人的人体骨盆控制问题,设计了基于绳索驱动的伺服控制系统,通过Matlab提供的sisotool进行PI和PD控制器的设计,并对张紧力、位置和二者之间的相互影响进行了仿真分析,证明了绳索驱动适合对骨盆规律的控制,并且可以在其他绳索牵引控制技术上得到应用和推广.     

Control and simulation of a tensegrity-based mobile robot

Tensegrity structures can provide a new approach to the construction of mobile robots with different shapes and properties that usual robots, wheeled or legged, do not have. Tensegrity are light, deformable structures that may be able to adapt their form to unconstrained environments. The main issue of this paper is twofold, first, to derive appropriate and general dynamic equations of motion to study the movement of such structures in the space; second to demonstrate, by means of simulation, that a tensegrity structure can execute any desired trajectory path by actuating some or all of its elements.     

新型六自由度机械臂的运动学分析与仿真验证

针对新型机器人六自由度机械臂的构型特点,采用传统的D-H法建立机械臂的连杆坐标系和运动学方程.在此基础上对传统的逆运动学求解的解析法进行改进,对得到的多组解采用能耗最小原则进行优化得出最适合的一组解.用MTALAB/SIMULINK搭建仿真模型,验证所得结果的正确性并分析所得结果的误差,仿真结果表明针对于此种构型机械臂的逆运动学求解,该方法无误差、耗能小,为类似构型的机械臂逆运动学求解提供了思路.     

资源动态加载算法在农机仿真平台中的实现

在搭建农机仿真平台时,若虚拟农场里的资源过多,使用Unity3D软件默认的一次性加载机制会使载入过程十分缓慢,用户需要漫长的等待时间.针对这个问题,使用资源动态加载算法优化资源的加载过程,使平台更加流畅运行.本文主要阐述了动态加载算法的原理和实现过程.     

Improved control and simulation models of a tricycle collaborative robot

The objective of collaborative manufacturing is to create the synergism from the collaboration of manufacturing resources. Most of the studied collaborations are made among intelligent machines; however, the collaboration can be realized even between machines and human being, and a collaborative robot (Cobot) belongs to the latter. A cobot is a robot designed to assist human beings as a guide or assistor in a constrained motion. Various prototypes have been developed and the potentials of these robots have been demonstrated. The research presented in this paper focuses on the control and simulation models of a tricycle cobot with three steered wheels, with the following two contributions: (i) A concise model for the closed-loop control is developed. Existing closed-loop control has been implemented in an intuitive way, and some control parameters have to be determined by a trial-and-error method. (ii) A simulation model is proposed to validate the control algorithms. No simulation model is available and the control models of other existing systems have to be validated experimentally. The developed control and simulation models have been implemented. Graphic simulation is also developed. Case studies are provided and the simulation results are analyzed.     

自主移动机器人平台的设计研究

本文介绍的自主移动机器人平台具有开放性,平台开发采用模块化、分布式结构,能根据用户的不同需求实现相应的配置。可适用于服务、医疗、搬运等行业,具有广泛的参考价值。     

GPU parallelization of an object-oriented nonlinear dynamic structural analysis platform

This work parallelized a widely used structural analysis platform called OpenSees using graphical processing units (GPU). This paper presents task decomposition diagrams with data flow and the sequential and parallel flowcharts for element matrix/vector calculations. It introduces a Bulk Model to ease the parallelization of the element matrix/vector calculations. An implementation of this model for shell elements is presented. Three versions of the Bulk Model—sequential, OpenMP multi-threaded, and CUDA GPU parallelized—were implemented in this work. Nonlinear dynamic analyses of two building models subjected to a tri-axial earthquake were tested. The results demonstrate speedups higher than four on a 4-core system, while the GPU parallelism achieves speedups higher than 7.6 on a single GPU device in comparison to the original sequential implementation.     

Kinematic and dynamic design and optimization of a parallel rehabilitation robot

In this paper, a method for concurrent optimum design of a complex parallel manipulator is introduced. The manipulator is a three-degree-of-freedom mechanism used as a walking rehabilitation device. The proposal deals with several optimization issues; firstly, the methodology is applied to a system recently designed and, in the best of our knowledge, the control policy, and dynamic model have not been published before, secondly, we propose an objective function which considers dexterity and singular manipulators, as well as energy and position error, and thirdly, we propose an optimization algorithm which successfully approximates the optimum solution, delivering low-cost feasible designs with fewer function evaluations than a comparing Genetic Algorithm. A set of numerical simulations validate the methodology and evidence its robustness since it delivers quite similar designs in several independent executions.