A simulation platform for optimal selection of robotic belt grinding system parameters

Robotic belt grinding is an effective process for removing material from geometrically complex workpieces. However, due to the relatively low stiffness of the system, the grinding quality is prone to inaccuracies caused by system dynamics. In order to control the quality of the grinding process, a profound understanding of the system is required. This paper presents a platform for comprehensive modeling and simulation of the robotic belt grinding system. The system kinematics model is based on the CAD model of the workpiece in composition with robot kinematics. The dynamics model is a comprehensive combination of the dynamics of the robot, the grinder, and the interaction between the grinder and the workpiece. A material removal model of the grinding process, which can adapt to workpieces with complicated shapes, is also developed and presented. The system simulation shows that optimal selection of key control parameters of the grinder and proper selection of robot control strategies can efficiently suppress chatter in the grinding process. Furthermore, having the ability to predict material removal rate, the comprehensive simulation platform is also demonstrated to be a strong tool in selecting the grinding process key parameters, namely, robotic velocity and contact force, for the control of material removal to meet dimensional accuracy requirements on workpieces.     

基于结构光的微细管孔内表面三维重建

介绍了一种适于空间曲线型微细管孔内表面三维重建的系统。该系统主要由管道机器人、形貌检测器和曲率检测器等部分组成。形貌检测器在管道机器人的带动下潜入管孔内部进行内壁截面图像采集，曲率检测器负责测量管孔中心轴线在检测器采样位置处的局部几何性质。对管道内壁截面图像进行适当的处理，结合形貌传感器的标定参数和结构参数，可以计算出在检测器局部坐标系下的管道截面三维轮廓；同时，根据传感器采样位置处的管道中轴线局部几何性质、管道机器人的前进步长，建立局部坐标系与全局坐标系的关系，从而将被测全部截面的局部坐标转化为全局坐标，实现管道内表面的三维重建。实验结果表明，利用该技术检测的管道内表面三维形貌与实际情况是一致的。     

Dynamic load-carrying capacity of mobile-base flexible joint manipulators

A computational technique for obtaining the maximum load-carrying capacity of robotic manipulators with joint elasticity is described while different base positions are considered. The maximum load-carrying capacity which can be achieved by a robotic manipulator during a given trajectory is limited by a number of factors. Probably the most important factors are the actuator limitations, joint elasticity (transmissions, reducers and servo drive system) and relative configuration of the robot with respect to its base. Therefore, both actuator torque capacity constraint considering typical torque-speed characteristics of DC motors and trajectory accuracy constraints considering a series of spherical bounds centred at each desired trajectory are applied as the main constraints. For the desired trajectory of load, different base locations are considered. It is seen that the load-carrying capacity at different base positions is different due to distinct dynamic effects of links and load motions on joint actuators. Then, a general computational algorithm for a multi-link case on a given trajectory and different base location is laid out in detail. Finally, two numerical examples involving a two-link manipulator and a PUMA robot using the method are presented. The obtained results illustrate the effect of base location, dual actuator torque and end effector precision constraints on load-carrying capacity on a given trajectory .     

一种正交并联机器人的灵巧度指标及其分布

并联机器人的灵巧度是衡量输入与输出运动 (力 )之间传递精度的重要指标 ,研究灵巧度在工作空间内的分布规律 ,对并联机器人的任务规划和控制意义重大。基于力Jacobian矩阵和Jacobian矩阵 ,提出新型 6 -SPS正交并联三维平台机器人机构的灵巧度指标 ,给出这些指标在工作空间内的分布情况 ,为该种三维平台机器人机构的进一步研究和实用化提供理论基础     

6R型串联机器人控制系统的软件实现

基于Windows系统平台和VC6．0编程环境,结合ACR9000运动控制器实现了机器人模块化控制系统的设计。整个系统能够实现机器人示教、机器人运动指令生成、指令识别与运动再现以及运动状态监控等功能。此控制系统在自主研发的多功能6R型串联机器人平台上运行平稳。     

机器人机构上任意点速度雅可比矩阵及其自动生成

推导出串联机器人机构上任意点的速度和雅可比矩阵计算公式,在此基础上,编制出机器人机构任意杆件上任意点的雅可比矩阵自动生成程序.对于两自由度机器人和PUMA560机器人的计算实例证明了程序的有效性.该程序可作为机器人机构雅可比矩阵自动生成的实用工具.     

4自由度混联机器人静刚度分析

研究一种新型混联机器人模块-Bicept的半解析刚度建模方法。该模块由一含恰约束支链的2自由度平面并联机构和一与动平台末端串接的2自由度转头构成,是Tricept机器人的一种二维形式,具有制造成本低,工作空间大的特点,配以长行程导轨,可用于飞机壁板数字化自动制孔等场合。在完成2自由度并联机构位置逆解分析和变形分析基础之上,基于全变形雅可比矩阵建立该机构的静刚度半解析模型。建模中考虑了所有支链构件及铰链的弹性贡献,并侧重研究其恰约束支链弯曲刚度的精确建模问题。通过算例获得Bicept机器人面内静刚度在工作空间中的分布规律,并通过ANSYS有限元分析软件验证了计算结果的正确性。     

Multi-point location theory, method, and application for flexible tooling system in aircraft manufacturing

To solve problems in aircraft manufacturing, flexible tooling system with “Forming-Machining” process is presented. Pointwise degree of freedom is defined on aircraft large-scale thin-wall workpiece during its machining process where traditional six-point location principle is not suitable, and base on which adaptive multi-point location method used for this kind of workpieces is described. Furthermore, multi-point location/support algorithm is developed to solve positions of location/support spheres of flexible tooling system to construct envelope surface of workpiece and avoid machine tool interference. Test data of sample workpiece show that flexible tooling system meets the requirements of aircraft large-scale thin-wall workpiece machining with manufacturing error and cycle decreased.     

Development of a Robotic System which Assists Unmanned Production Based on Cooperation between Off-Line Robots and On-line Robots. Part 3. 1 Development of an Off-Line Robot, Autonomous Navigation, and Detection of Faulty Workpieces in a Vibrating Parts Feeder

Remarkable advances in robotics and intelligent technology have made unmanned production realisable. Based on the off-line robot concept proposed in our first paper, an off-line robot and peripheral devices have been developed for the realisation of unmanned production. The developed robot has a power-wheeled steering (PWS) type mobile platform on which a double-arm manipulator is installed. In order to detect and recognise 3D objects, double CCD cameras are mounted on the top of the robot. Two types of robot end-effectors are developed to handle workpieces and conduct trouble shooting actions. A newly developed production trouble simulator is very useful in simulating and resolving production troubles. A virtual pilot plant for production composed of the off-line robot, two on-line robots, a vibrating bowl feeder, a belt conveyor and a production trouble simulator has been constructed and tests for production simulation have been undertaken. In this paper, autonomous navigation of the developed robot in the virtual pilot plant is investigated. Then a search for faulty parts in a parts feeder using the developed real-time image extraction method is carried out.     

运载火箭自动加注机器人结构设计及有限元分析

针对运载火箭推进剂加注自动化过程的实现,设计了一种能够与箭体连接头自动对接与脱离的加注机器人。该机器人以管道机械臂作为机器人本体,配合激光雷达实现自动定位与跟踪。机械臂既是机器人定位跟踪的载体也是推进剂加注管道,加泄连接器安装在机械臂末端,作为与箭体连接头对接的机械载体。利用建模软件建立机器人三维实体模型,将模型简化后导入SolidWorks Simulation进行有限元分析,得到了其应力云图以及变形位移图,通过分析验证了机构设计的可靠性和合理性。     

Design of an adaptive-robust controller for a powder coating robot and its comparison with inverse dynamic approach

In this research, the design and function of “DAP”, a 3-DOF ‘RRP’ (rotational/prismatic) dual-acting pick-and-place-painting robot, are first briefly presented and, along with its kinematic and dynamic analysis, is studied to eliminate the man presence in industrially polluted environment such as coating processes. The main function of this robot is coating epoxy powder on “Hawle” gate valves at temperatures up to 200°C. Then, the movement and control simulation trend for maneuvering in optimization path are described by non-linear inverse dynamic and adaptive-robust controllers as modern control methods regarding to angle and torque feedback systems in industrial robots. Comparison of these control approaches is considered in relation to uncertainties. The results obtained from this research could greatly satisfy the need for overcoming uncertainties in such combined industrial processes.     

An innovative subdivision-ICP registration method for tool-path correction applied to deformed aircraft parts machining

A new and fast registration algorithm has been proposed to update the tool-path of a deburring robot, intended to machining composite workpieces under gravity and clamping deformations. A Subdivision Iterative Closest Point algorithm, which considers different parts of the contour with respect to curvature, allows to obtain far better results than classical methods, without complicated assumptions or computations. The procedure has shown to be effective for porthole and nose-cone deburring. Experimental tests conducted on robotic milling workcell demonstrated the efficiency of the registration method.     

Development and calibration of an integrated 3D scanning system for high-accuracy large-scale metrology

Quality control in advanced manufacturing requires automated and high-accuracy large-scale 3D measurement. This paper proposes a high-accuracy, low-cost 3D scanning system by integrating industrial robot with precise linear rail and laser sensor. The measuring principle and system construction of the integrated system are introduced in detail. A mathematical model is established for mapping the change of the laser sensor frame while it scans along the linear rail and a sphere-based algorithm for rail orientation calibration is introduced. Subsequently, taking the robot positioning error into consideration, an enhanced hand–eye calibration method is proposed to determine the relationship between robot end-effector and rail scanning frame. Validation experiments were performed, a maximum distance error of 0.071 mm was detected within the rail range and a mean/maximum distance error of 0.309/0.604 mm was detected in the robot volume. A large-scale scanning instance also shows that integrated robotic scanning system features high-efficiency and high-accuracy.     

基于SolidWorks的五自由度打磨机器人虚拟装配设计

介绍一个基于SolidWorks软件设计开发的五自由度打磨机器人参数化建模及装配设计平台。利用SolidWorks软件基于特征、参数化、实体建模的设计方法,完成五自由度打磨机器人三维零件模型;利用SolidWorks非常强大的装配功能,完成五自由度打磨机器人各子装配和整体装配,并对关键零部件进行干涉检查;利用SolidWorks的工程图模块生成2D工程图。     

激光涂层零件的疲劳撞击可靠性寿命试验分析

制备了自熔合金粉末激光熔覆涂层试件，在多次撞击疲劳试验机上进行了可靠性试验，获得了相应的P—S—N曲线，考察了不同涂层材料对试件疲劳强度和可靠性寿命的影响。对多次撞击载荷下涂层零件的典型失效过程和涂层与基体的疲劳累积塑性变形进行了初步分析。     

新型两用表面形貌测量仪的研究与开发

开发了一种大量程、高分辨率、非接触式与接触式测量两用的新型表面形貌测量仪器。仪器本体为非接触测量轮廓仪,通过插入接触式测头实现接触测量。非接触式测头采用傅科法自动聚焦原理,接触式测量采用微恒力电感测量原理,它们共用一个音圈电机,各自跟踪电气零位,实现大量程、高分辨率的位移测量。文中还介绍了仪器采用的共运动基面二维工作台。     

Quadric segmentation and fitting of data captured by a laser profile scanner mounted on an industrial robot

Applications like geometric reverse engineering, robot vision and automatic inspection require sets of points to be measured from the surfaces of objects and then processed by segmentation and fitting algorithms to establish shape parameters of interest. In industrial applications where speed, reliability and automatic operation is of interest a measuring system based on a laser profile scanner mounted on an industrial robot can be of interest. In earlier publications we have presented such a system and also a segmentation algorithm for planar surfaces using 2D profile data in combination with robot poses. Due to the data reduction offered by this approach the segmentation algorithm computes faster than algorithms based on 3D point sets alone. Encouraged by the results we have now developed a segmentation algorithm for two different quadric surfaces also based on 2D profiles in combination with robot poses. This paper presents the new algorithm together with test results and also an interesting observation that points to future work.     

基于强化学习的机器人手臂仿人运动规划方法

面向人-机器人交互共融环境对机械臂仿人运动规划的重大需求,本文提出了一种基于强化学习的机器人手臂仿人运 动规划方法。 首先,基于人体手臂的结构特征,设计了体现机械臂运动特性的肩夹角、肘夹角和腕关节运动角,并采用正态性和 相关性分析方法,对 VICON 运动捕捉系统获取的人体手臂运动数据进行分析,以获取人臂运动特性规则。 然后,根据不同的运 动特性规则,设计对应的回报函数,并采用强化学习方法进行机械臂仿人运动模型的训练。 最后,搭建机械臂仿人运动平台,实 验统计仿人运动的成功率为 91. 25% ,验证了所提规划方法的可行性和有效性,可用于提高机械臂运动的仿人性。     

组合CCD图像和稀疏激光测距数据的建筑物三维信息提取

对组合高分辨率航空CCD图像和机载稀疏激光扫描测距数据自动提取城市建筑物的三维信息进行了研究。航空CCD图像能清晰地给出建筑物的几何形状和分布,因此采用了自适应的Canny边缘检测算法来提取CCD图像上的全部边缘信息,然后根据双向投影直方图和线段匹配方法来自动而准确地提取建筑物的平面轮廓信息,最后根据CCD提取的轮廓信息从机载激光扫描测距数据中提取建筑物的高度信息,从而实现了每栋建筑物的三维信息提取。通过实际数据的处理和提取,说明了组合CCD图像和机载激光扫描测距数据可以自动重建建筑物的三维信息。     

Planar segmentation of data from a laser profile scanner mounted on an industrial robot

In industrial applications like rapid prototyping, robot vision, and geometric reverse engineering, where speed and automatic operation are important, an industrial robot and a laser profile scanner can be used as a 3D measurement system. This paper is concerned with the problem of segmenting the data from such a system into regions that can be fitted with planar surfaces. We have developed a new algorithm for planar segmentation based on laser scan profiles and robot poses. Compared to a traditional algorithm that operates on a point cloud, the new algorithm is shown to be more effective and faster.