Generation and Simulation of Robot Trajectories in a Virtual CAD-Based Off-Line Programming Environment

This paper presents a new approach to the generation and optimisation of the position and orientation trajectories in Cartesian task space, and simulation in a virtual CAD-based off-line programming environment. A novel concept of the robot pose ruled surface is proposed, and defined as a motion locus of the robot orientation vector, i.e. the vector of equivalent angular displacement. The planning for trajectories of robot end-effectors can be accomplished by generating the robot pose ruled surface and optimising its area under the constraints with good kinematics and dynamics performances. The established optimisation model is based on functional analysis and dynamics planning, and is simplified by using high-order polynomial space curves as the robotic position and orientation trajectories. The developed system, RoboSim, is a virtual integrated environment which can be used as a testbed for automatic motion planning and simulation for robots. Two examples are given to verify the feasibility of the proposed approach and models, and to demonstrate the capabilities of generation, optimisation, and simulation modules and libraries in the RoboSim package. The simulation results show that the approach and system are feasible and useful for motion planning, performance analysis and evaluation, and CAD-based prototyping and off-line programming in both the virtual and the real design and planning environment.     

Reconfigurable robotic machining system controlled and programmed in a machine tool manner

Industrial robots represent a promising cost-effective and flexible alternative for some machining applications. This paper describes the concept of reconfigurable robot multi-axis machining systems for machining the complex parts of light materials with lower tolerances having freeform surfaces. For the basic configuration of a five-axis robotic machining system, the robot modeling approach is shown in detail as well as the prototype of developed control system with programming in G-code. The experimental robotic machining system has been verified by successful machining of several test work pieces.     

基于复杂零件五轴加工系统的可重构机器人建模与试验

将数控机床的通用编程语言G代码应用于加工轻质材料、低公差自由曲面复杂零件的可重构机器人多轴加工系统,并将复杂曲面加工的五轴立式关节机器人视为倾斜五轴（X,Y,Z,A,B）立式铣床的特殊配置,开发出了机器人的控制系统原型。阐述了机器人的建模方法,包括运动学问题的正向解和逆向解的求解方法;分析了机器人三轴、五轴加工时的工作空间;通过三个轻质材料试件的加工试验,验证了实验机器人加工控制系统原型的编程、控制和加工能力。     

Development and Polishing Process of a Mobile Robot Finishing Large Mold Surface

□ A novel self-determination polishing robot finishing large mold free-form surface is developed, and the finishing process method is researched. Contrary to traditional approaches, our premise is that a large mold surface can be polished by using a small robot. This robot system is mainly composed of a polishing robot part, a computer system and a visual positioning system. A type of robot with four uniform distribution wheels was designed, which has two driving wheels and two driven wheels. Active compliant control of the polishing tool was provided by a pneumatic servo system, and a new special compliant abrasive tool was proposed on the basis of robot characteristics. The process planning steps consisted of subdividing the free-form surface, choosing an abrasive tool, planning the polishing path and optimizing machining parameters. Based on the orthogonal experiment and the grey relational analysis method, the optimal parameter combination was obtained for polishing force, tool speed and feed rate. Aiming to polishing times, the surface roughness method and polishing efficiency method were studied in detail. The polishing experiments were carried out in the robot using process parameters obtained by the efficiency method. These research results provided significant theory foundation and experimental data for a mobile robot planning polishing to realize intelligible process parameter selection.     

空间机器人遥操作系统设计

为了帮助操作者快速直观地规划空间机器人轨迹,开发了一种遥操作系统,该系统由预测仿真 软件、图像监控软件、任务规划软件和手控器４个子系统构成。基于遥操作系统进行了３项实验。一是对于 系统的双边力反馈功能进行了实验,操作者可以根据时延大小实时调整手柄运动的速度;二是进行了单关 节故障仿真实验,通过容错规划后空间机器人仍能以固定姿态完成观测成像任务;三是进行了碰撞检测仿 真实验,利用实时遥编程功能可以验证规划路径的合理性,避免碰撞发生。     

Mathematical models for base calibration in industrial robots

Mathematical models for the control systems of industrial robots permit calibration of the base, which is a single coordinate space for the industrial robot and the components being manipulated. Calibration of the base precedes operation of the robot. Control systems for industrial robots permit the storage and use of several calibrated bases in programming robot motion.     

基于UG二次开发的工业机器人作业仿真系统设计

为了在一般CAD软件中实现符合企业需求的工业机器人运动仿真,通过采用UG软件二次开发技术和C++程序,构造了与UG无缝集成的工业机器人作业仿真系统。设计了包含人机接口层、作业管理层、UG支撑层的仿真软件体系结构。针对UG运动模块难以进行二次开发的问题,通过对UG装配模块的二次开发来实现机器人运动仿真。机器人运动过程碰撞检测功能则由UG间隙检查模块的二次开发实现。仿真软件现已成功地应用于汽车门框焊接机器人的作业仿真及布局设计。     

A method for off-line compensation of cutting force-induced errors in robotic machining by tool path modification

Industrial robots are promising cost-effective and flexible alternatives for multi-axis milling applications in machining of complex parts of light materials with lower tolerances, having freeform surfaces. As it is well-known, the poor accuracy, stiffness, and the complexity of programming are the most important limiting factors for wider adoption of robotic machining in machine shops. The paper presents the developed method for off-line compensation of machining robot tool tip static displacements as a dominant part of cutting force-induced errors. The developed method is based on modification of programmed trajectory in G-code. Off-line modification of programmed trajectory is performed according to the predicted static tool tip displacements calculated based on developed robot compliance model and cutting forces predicted by mechanistic model. The obtained experimental results show the relevance of developed method since the machining errors could be significantly reduced. This allows the desired accuracy of robot machining to converge towards nominal specifications.     

机器人钣金折弯路径规划与仿真研究

针对钣金折弯机器人示教编程过程烦琐、效率低的问题,提出一种基于 Coin3D 的折弯机器人运动仿真系统方案。基于 Coin3D 虚拟场景技术,为折弯单元各组件建模,完成折弯单元加工环境的参数化配置和导入,实现仿真环境构建。为适应钣金工件随折弯加工逐步变形的特点,设计了对应的双向链式数据模型;分析了折弯机器人典型操作任务目标位姿的确定方法,并在此基础上参考人工示教经验,提出折弯机器人路径规划方法,实现了折弯机器人折弯加工的运动仿真。仿真实验验证了仿真系统和相关模型与方法的正确性,为折弯机器人离线编程系统研发奠定了基础。     

Robocell: A computer-aided robots modelling and workstation layout system

The use of computer simulation to assist in robot selection and programming and to evaluate robotic workcell layout provides the user with an effective tool for planning new robot installations or modifying existing ones. It enables the system planner to examine robot reach and geometry features, calculate cycle time and plan, develop and debug task programs prior to installation. This paper discusses the robot modelling and interactive graphics techniques used in the robot/cell simulation package ROBOCELL. Three industrial robots are used in examples to illustrate the kinematic and geometric modelling, cycle time computation and program features of ROBOCELL. A detailed model of a cylindrical robot is outlined. The application of the simulator for designing a flexible final motor assembly workcell and a packaging/palletising workstation is described.     

工业机器人喷涂运动学仿真研究

为了提高工业机器人设计分析效率,降低昂贵的机器人开发成本,利用虚拟样机技术对机器人进行了运动学仿真,提出了机器人的轨迹规划。根据HA006型工业机器人的结构特点,建立了基于D—H连杆坐标系的机器人运动学模型,利用MATLAB软件的机器人工具箱构建机器人对象,求解机器人基于关节坐标和直角坐标的轨迹规划,并通过SolidWorks软件进行连续路径喷涂轨迹规划的运动学仿真与分析,较为直观地观察机器人工作姿态和运动轨迹,得到机器人运动性能的实时状况。试验结果表明,该方法可以清楚地判定机器人运动方案的合理性及轨迹规划及控制算法的可行性,有效地提高了工业机器人的设计效率。     

缠绕机器人CAD/CAM系统设计及应用

针对复杂异形复合材料制品纤维缠绕成形装备缠绕不适应的问题,研究了基于工业机器人的纤维缠绕CAD/CAM系统。采用局部曲面缠绕法,对复杂异形复合材料制品进行了缠绕线型设计。基于机器人关节轨迹高阶多项式规划法,对多种运动形式的机器人缠绕轨迹进行规划,开发了一套可实现异形件缠绕线型设计、缠绕轨迹规划、可执行代码文件自动生成及缠绕设计过程可视化的机器人缠绕CAD/CAM系统。组合回转体缠绕实验验证了该系统的实用性。     

基于MATLAB-Robotics工具箱的工业机器人轨迹规划及仿真研究

对Cincinnati T3-746工业机器人的运动学轨迹规划进行了分析与仿真。通过实验对该工业机器人的三关节的关节轨迹进行了三次多项式插值运算。利用MATLAB-Robotics工具箱对该工业机器人进行了建模,实现了对工作空间内任意直线、圆弧轨迹拟合插值运算。通过运动学正反解的计算,得到了实时的关节空间坐标的数值解。为该工业机器人进一步的研究和应用提供了理论分析依据。     

Nanofinishing of freeform surfaces (knee joint implant) by rotational-magnetorheological abrasive flow finishing (R-MRAFF) process

Freeform complex surfaces have become an inevitable part of many devices to perform specific functions. Some of these components require nanolevel surface roughness value to meet the desired requirements in their applications. Finishing of freeform surfaces to nanometer surface roughness value is always difficult for any process. Rotational-magnetorheological abrasive flow finishing (R-MRAFF) process has been applied so far for finishing internal surfaces of relatively simple geometry. In this work, an attempt has been made to improve external topography of freeform surfaces using this process. Large hydrodynamic pressure coupled with magnetic fluid is the principal idea behind these experiments. A smooth mirror like finished surface is achieved with improved finishing rate (nanometer/min) by controlling two motions (axial and rotational) simultaneously on stainless steel workpiece similar to knee joint implant. Magnetorheological polishing fluid with different mesh sizes of abrasive particles and at different extrusion pressures is used to reduce final surface roughness value, to increase uniformity of surface finish on the freeform surface and to enhance finishing rate. Surface roughness ranging from 35 to 78 nm is achieved at various locations as compared to larger variation in Ra value obtained in the earlier research work.     

多轴联动曲面研磨机床的路径规划研究

以研制多轴联动数控研磨机床为背景,按照机床的特性和加工表面粗糙度的要求,提出了自由曲面的变曲率分片方法,并与仿人螺旋线研磨轨迹的规划算法相结合来提高表面精度。其算法简单、运算速度快、通用性强。最后,利用Matlab软件对该算法进行验证和仿真,其结果表明该规划轨迹较为理想。     

码垛机器人控制系统的设计与实现

介绍了混联机构的搬运码垛机器人控制系统的设计与实现方法,根据工作现场的实际需求,对离线码垛过程进行了研究,通过码垛关键参数的输入和码垛空间判断,建立离线编程的基础,给出了机器人码垛的路径规划,硬件控制系统采用工业PC（IPC）作为主计算机,利用分布式二级控制结构实现系统的监控和作业管理,协调各关节的运动,准确地跟踪轨迹规划。软件系统运用了PLC来控制机械人手爪且自主开发码垛机器人控制软件,通过码垛关键参数的输入及示教盒控制方式,经实际使用结果证明控制系统的有效性与合理性。     

机器人柔顺力控装置研究

机器人自动化抛光过程中,工具与工件间的接触力控制尤为重要.基于主动柔顺控制的原理,提出了面向工业机器人的柔顺力控装置及控制方法.进行了系统的结构设计和动力学建模,基于BP神经网络PID算法,设计了该柔顺力控装置的自适应控制策略.最后进行力控跟踪实验,实验结果表明,柔顺力控装置能够保证打磨过程中工件与工具之间的接触力恒定...     

Trajectory coordination planning and control for robot manipulators in automated material handling and processing

Motion coordination planning and control play a crucial role in robot application to Cartesian task operations with taking into account kinematics and dynamics constraints. This paper presents a unified approach to coordination planning and control for robot position and orientation trajectories in Cartesian space. The concept of generalised robot pose is defined as the robot configuration consisting of position and orientation, in which the orientation is described by a vector equivalent to the rotational angular displacement. The robot pose ruled surface is formed as a three-dimensional motion locus of its configuration vector. The unified treatment of the end-effector positions and orientations is based on the robot pose ruled surface concept and used in trajectory interpolations. The coordination planning of pose trajectories for the robot end effector is accomplished by generating and optimising the pose ruled surface under the constraints of kinematics and dynamics performances. The coordination control is implemented through controlling the motion laws of two end points of the orientation vector and calculating the coordinates of instantaneous corresponding points. The simulation experiment using PUMA 560 robot in arc welding and surface finishing processes are carried out to verify the feasibility of the proposed approach and demonstrate the capabilities of generation and control models.     

Electrochemical mechanical polishing technology: recent developments and future research and industrial needs

Electrochemical mechanical (ECM) polishing processes are widely used in various industries such as die and mould manufacturing, turbine blades, and components with complex surfaces. They are used to improve the surface quality and get glossy surfaces with enhanced mechanical properties. In this paper, the authors first look into the fundamental principles of the ECM polishing technology. Then the main parameters that affect the ECM polishing process such as applied voltage, electrolyte concentration, rotational speed and polishing pressure are discussed, and the related research issues are raised. Studying these parameters will enhance the performance, increase the efficiency of ECM polishing technology and provide a useful reference for further developments. Up to date, automatic ECM polishing is limited for planarization process and surfaces with simple geometry such as hole-wall and rotary surfaces. In addition, in some of ECM finishing technologies, the limited available working space usually forces the manufacture to machine one part in multiple stages. Because robots have some advantages over conventional machines such as flexibility, low price and mechanical reconfigurability, they are an effective and economical solution for ECM polishing of geometrically complex workpieces. In order to advance the ECM technology for the next competitive stage where a promising quantitative and qualitative processing is required, the authors proposed that the future researches on ECM polishing should also include ECM polishing using robots. In addition, the authors propose several configurations and setups of robotic ECM polishing systems. The research topics in this area should include designing of new ECM polishing tools, investigating the synergistic effects of additional sources of energies such as magnetic field and ultrasonic vibrations besides the normal effect of ECM tools and developing models and control methods of the processes.     

可重构模块化工业机器人构形及其静力学分析

可重构模块化工业机器人是机器人学研究领域中兴起的一个新的研究方向,其核心和基础内容是可重构工业机器人的模块划分和模块组合运动规划。分析可重构模块化工业机器人的特点,以50kg负载工业机器人为例,介绍了工业机器人模块的划分,结合课题所涉及的具体实例分别对工业机器人的各个模块进行了详细的叙述。采用基于SolidWorks的三维建模和基于ANSYS的结构性能分析相结合的方法,完成50kg负载工业机器人本体的构建,实现了工业机器人的可重构化。