飞机载荷校准虚拟试验建模方法研究

载荷校准虚拟试验可以实现对真实试验的外推、预测以及模拟演练等。建模的优劣影响了载荷校准虚拟试验对真实试验的逼真度,决定了虚拟试验的成败。本文以某型飞机机翼为例,研究了载荷校准虚拟试验建模的各个环节,包括有限元建模、虚拟应变电桥建模、约束及载荷建模和模型修正等,形成了载荷校准虚拟试验的建模方法。     

Full-pose calibration of a robot manipulator using a coordinate-measuring machine

The work reported in this article addresses the kinematic calibration of a robot manipulator using a coordinate measuring machine (CMM) which is able to obtain the full pose of the end-effector. A kinematic model is developed for the manipulator, its relationship to the world coordinate frame and the tool. The derivation of the tool pose from experimental measurements is discussed, as is the identification methodology. A complete simulation of the experiment is performed, allowing the observation strategy to be defined. The experimental work is described together with the parameter identification and accuracy verification. The principal conclusion is that the method is able to calibrate the robot successfully, with a resulting accuracy approaching that of its repeatability.     

Kinematic parameter calibration method for industrial robot manipulator using the relative position

A new calibration method for industrial robot system calibration on a manufacturing floor is presented in this paper. To calibrate the robot system, a laser sensor to measure the distance between robot tool and measurement surface is attached to the robot end-effector and a grid is established in the floor. Given two position command pulses for a robot manipulator and using the position difference between two command pulses, the relative position measurement calibration method will find the real robot kinematic parameters. The procedures developed have been applied to an industrial robot. Finally, the effects of the models used to calibrate the robot are discussed. This calibration method represents an effective, low cost and feasible technique for the industrial robot calibration in lab. projects and industrial environments.     

Crosstalk calibration for torque sensor using actual sensing frame

Accurate load sensing is crucial to robots’ performance of various tasks undertaken to assist workers. Most of the research on load sensing by robot manipulators has focused on improving force/torque sensor hardware. Torque sensors suffer from crosstalk, which cannot be compensated, not even through calibration. Thus, for minimization of crosstalk, torque sensors require precise machining and a complicated structure, which often increase costs. This paper proposes an alternative, novel calibration method. In this scheme, first, the compliance matrix of the torque sensor is obtained from sampling data, and then the location and scale of the actual sensing frame, in which crosstalk-free load sensing occurs, can be estimated. Using the proposed calibration method, the external load acting on the end-effector can be sensed accurately, even with relatively low-quality torque sensors. Experimental results show that measurement accuracy was significantly improved with the proposed method.     

Kinematic calibration for a hybrid 5DOF manipulator based on 3-RPS in-actuated parallel manipulator

The measurement method is a decisive step for any calibration method. This paper studies the practical performance of a 5DOF manipulator based on a 3-RPS parallel mechanism. By comparing the controlling data that resides in parallel part and serial part at different orientations, a calibration method has been put forward and proved to be applicable. The precision of the calibrated model mainly depends on the number of measurements carried out. The distribution of measurement points also affects the precision and the measurement number could be significantly reduced if uniform distribution were ensured.     

高速并联机械手运动学标定方法

以可实现2平动自由度运动的并联机械手——Diamond机械手为研究对象,提出一种具有分层递阶格式的误差辨识和补偿方法,该方法以动平台参考点初始位置为标定坐标系原点,首先辨识并补偿主动臂回零转角误差．而后再辨识并补偿其它几何参数误差。实验结果验证了该方法的有效性。     

Plane-motion approach to manipulator calibration

It is well known that identification of geometric parameters can significantly enhance the accuracy of robot manipulators. A number of different approaches to manipulator calibration have been demonstrated in the recent literature. A part of the calibration process that is common to all of the proposed techniques is the collection of a dataset that relates the measured position and possibly the orientation of the end-effector to the joint displacements for a number of poses. This data-acquisition step is usually the most tedious part of the calibration process. Accurate location of points on the end-effector can be quite time consuming to accomplish manually and the equipment for automated data acquisition is expensive. The purpose of this work, therefore, is to demonstrate a simplified approach to acquiring the data necessary for manipulator calibration. In the proposed approach, the only equipment used for data measurements is a flat plate and a test block mounted on the end of the robot arm. To demonstrate the method, a model and an identification algorithm for a PUMA 560 manipulator are developed. The data-collection process is described and the procedure is validated through a computer simulation. Finally, an experiment is conducted whereby data is collected for a PUMA manipulator and used to identify the kinematic parameters. The resulting manipulator model leads to a significant improvement in accuracy.     

Characterization of a heat flux sensor using short pulse laser calibration

A method to calibrate classical heat flux sensors is presented. The classical approach to measure the temperature inside a known material by using a thermocouple fails when the measurement time is very short. In this work the surface heat flux is determined by solving the inverse heat conduction problem using a noninteger identified system as a direct model for the estimation process. Using short pulse laser calibration measurements the crucial design aspects of the sensor that play a significant role when assuming one-dimensional, semi-infinite heat transfer have been accounted for. The theoretical approach as well as the calibration results are presented and comparisons to the classical approach and results from finite element modeling are shown. It is concluded that the new method ameliorate the heat flux sensor significantly and extend its application to very short measurement times.     

Proximity sensor technology for manipulator end effectors

Optimal proximity sensing devices suitable for hand mounting on a manipulator are described, which use near IR LED light sources operating at 0.94μ and silicon detectors, with appropriate signal processing so that the data are unaffected by ambient light. Laboratory tests with simple proximity sensors are described. Extension of the same techniques to yield multipoint or digital sensors are also discussed. A cooperative proximity sensor concept is described, which employs a composite mirror attached to the work piece to generate an unambiguous set of position and orientation signals. A very rudimentary experiment in local control of a manipulator with a pair of hand mounted proximity sensors is also described.     

基于COSMOSMotion的机械臂三维虚拟仿真

以六自由度蒸汽发生器检修机械臂三维运动仿真为背景,利用SolidWorks进行机械臂三维建模,并且介绍了利用COSMOSMotion插件来实现机械臂运动虚拟仿真的方法,重点分析了机械臂的三维建模和建模后运动学正反解的实现.对于一般的机械运动模拟系统,该实例具有一般普遍性.     

一种平面3RRR并联机器人结构参数识别

分析一种3RRR并联机器人的结构误差，利用其约束条件建立误差模型，提出一种结构参数识别算法，避免了传统参数识别算法需要进行的位置正解，从而简化了结构参数的识别。通过测量次数的适当增加，利用最小二乘原理处理数据，减小了输入输出参数的测量误差对参数识别的影响     

Optimal load of robotic manipulator with joint elasticity using accuracy and actuator constraints

A computational technique for obtaining the maximum load-carrying capacity for a robotic manipulator with joint elasticity, subject to accuracy and actuator constraints, is described. Full load motions and increased productivity are linked in the industrial applications of many robotic manipulators; the maximum load carrying capacity which can be achieved by a manipulator during a given trajectory is limited by a number of factors. The dynamic properties of a manipulator, its actuator limitations, and joint elasticity (transmissions, reducers, and servo drive system) are probably the most important factors. This paper presents a strategy for determining dynamic load carrying capacity (DLCC), subject to both accuracy and actuator constraints, where a series of cubical bounds centred at the desired trajectory is used in the end-effector oscillation constraint while a typical d.c. motor speed-torque characteristics curve is used in the actuator constraint. The technique which considers the full nonlinear manipulator dynamics, actuator constraints, and accuracy constraints permits the manipulator user to specify the trajectory completely. Finally, a numerical example involving a two-link manipulator with joint flexibility using this method is presented and the results are discussed.     

装卸机械手设计研究

对生产线上装卸机械手进行设计研究。用机器人机构学理论推导出装卸机械手运动学方程;完成了机械手结构设计、液压及PC控制系统的设计,选出了合适的PC控制器,设计了控制程序,满足了生产线的需要。     

虚拟环境下采摘机械手行为仿真

为优化荔枝采摘机械手设计,针对复杂环境下采摘机械手行为的复杂性和不确定性,采用VC++和EON SDK开发了采摘机械手行为仿真系统.分析给出了仿真系统体系结构,从采摘机械手建模和模型优化及层次结构装配、运动学模型建立、采摘环境构建、三维模型数据转换和人机交互等方面研究系统的实现过程.最后,在仿真平台上通过事件驱动与路由机制实现了虚拟环境下采摘机械手运动、采摘等行为仿真.     

Development of variable temperature instrument for sensor calibration

An experiment to calibrate temperature sensors at cryogenic temperature has been performed. The main objective of this study was to develop a precise instrument for calibrating the temperature sensors over a temperature range of 4 K to approximately room temperature without liquid helium. The instrument consists of radiation shields, a sensor block, an electric heater, a cryocooler and a vacuum chamber. In a vacuum chamber, the cold head of the cryocooler is thermally anchored to the sensor block to bring the apparatus to a desired temperature. An electric heater is placed at the second stage of the cryocooler to control the temperature of the sensor block. The entire apparatus is covered by radiation shields and wrapped in multi-layer insulation to minimize thermal radiation in a vacuum chamber. The dimensions of components including instrumental wires are optimized to reduce total heat invasion from room temperature into cryogenic temperature. The vacuum chamber is pumped down and cooled to cryogenic temperature by a cryocooler. The resistance of each temperature sensor is measured at steady state as well as cooling down and warming up cycles, and the performance of calibration is discussed with respect to the sensitivity and resolution.     

新型数控机械手的虚拟样机与仿真研究

设计了一种全新的经济型数控机床装夹机械手,通过一次调整能够对某一种待加工工件进行自动装夹及卸料,从而实现某一种待加工工件在数控机床上的自动加工,达到省工省时省力的目的.利用理论研究和假定条件设计出机械手结构,在ADAMS/View中建立机械手的虚拟样机;在分析多体力学理论的基础上建立了机械手多体动力学模型,并进行了相关理论求解,最后实现了机械手整个工作过程的运动仿真,得到了机械手的运动仿真数据,为后续新型机械手的设计和制造提供了依据.     

Kinematics analysis and numerical simulation of a manipulator based on virtual prototyping

Manipulator kinematics refers the analytical study of the motion of manipulator, such as positions, velocities, and accelerations of the links of a manipulator. As formulating the suitable kinematics models for a manipulator is very crucial for analyzing the behavior of manipulators and light weight design of manipulators, many researches have been focused on it in recent decades with a result of many valuable contributions. However, current researches always focus on rigid manipulator, while the manipulator is always a rigid-flexible coupling multibody system, which can affect the accuracy of kinematics analysis and numerical simulation. This paper proposed a model of kinematics analysis of manipulator based on rigid-flexible coupling virtual prototyping. After a model of manipulator kinematics based on the D-H method was proposed, rigid-flexible coupling virtual prototyping-based kinematics simulation and numerical simulation was then put forward. The kinematical experiment is carried out based on manipulator physical prototyping, which demonstrates that the accuracy of the kinematics calculation and the rationality of design based on rigid-flexible coupling virtual prototyping. The design of a five-degrees-of-freedom manipulator is given as an example, which demonstrates that the methodology is obviously helpful to manipulator design.     

Torque traceability examination of calibration laboratories in Korea

Torque is a physical quantity that is related to fastening bolt in various industry fields of assembling. The quality of assembling procedure is highly dependent on the accurate torque control. For the accurate torque measurement and control of torque, each torque transducer in industries should be calibrated using qualified torque calibration system. In Korea, there are 14 calibration laboratories for the torque measuring device. They have their own torque calibration system. Some of them are using deadweight torque calibration machine and the others have unsupported torque generating system using torque arm and masses.To check the reliability of the torque calibration laboratories, a series of round robin measurement was performed by the Korean National Measurement Institute, Korea Research Institute of Standards and Science (KRISS). This paper deals with the round robin measurement to check the traceability in torque in Korea. Two torque transfer standards each having 200 Nm capacity were used for the measurement. Measured value as well as the measured uncertainty of each laboratory was compared with those of KRISS.     

一种可变刚度的载荷校准试验调试台架

载荷校准试验是应变法飞行载荷测量工作中必要的环节,其试验结果决定着飞行载荷测量成败。通常载荷校准试验是在飞机上实施的,具有较大的风险,为此在正式试验前要进行加载设备调试、工况演示,进而实现工况优化,降低试验风险。针对调试试验提出了一种可变刚度的载荷校准试验调试台架,通过对空气弹簧调节台架整体刚度,实现机翼受载后的变形模拟。试验结果表明,该调试台架的功能和承载能力能够满足调试试验的需求,能实现大展弦比机翼的大变形模拟。     

电容式位移传感器的线性度标定与不确定度评定

由于光刻投影物镜装调中电容传感器的线性度指标不能够满足位移调节精度的需求,本文提出了一种提高电容传感器测量线性度的方法。该方法采用压电驱动器提供位移进给;采用高精度激光测长干涉仪校准电容传感器的线性度,提供位移反馈以保证运动控制精度。采用高阶曲线拟合方法得到拟合系数对传感器线性度进行在线标定;对标定实验中的环境、安装、机构以及控制等进行不确定度分析与评定以保证电容传感器的线性度测量精度;最后进行电容传感器线性度的标定实验。实验结果表明:本文提出的线性度标定方法能够减小各误差项对于测量结果的影响,标定后传感器线性度由0.047 14%提高至0.004 84%,近一个数量级,并且线性度重复性较高,重复性偏差为0.38nm,全行程内线性度的合成不确定度为5.70nm,能够满足光刻物镜中位移控制精度的需求。