双机器人系统的其坐标标定

多机器人协调系统研究中，机器人基坐标系之间的关系标定是一个重要而困难的问题，本文研究一种基于视觉传感的双机器人基坐标系关系的标定方法，通过一个机械手持有的摄像机观察另一个机械手末端的主动运动来实现。该方法独立于机器人系统中的其它关系的标定过程，由于系统自动完成，且不需要任何人工标定辅助。文中还给出了消除标一误差的直角坐标系坐标在交归一化的方法。仿真研究表明所给方法的有效性。     

典型安装方式的协作机器人基坐标系标定方法

针对地面式、侧墙式、顶棚式三种典型安装方式下的协作机器人的基坐标系标定问题,采用了一种新的操作步骤简单、标定结果精确的机器人基坐标系标定方法。该方法通过在协作机器人的公共空间中构造四点"握手"动作并分别记录接触点在每个机器人的基坐标系下的坐标,求解协作机器人基坐标系间的旋转矩阵和平移矩阵,从而得到协作机器人基坐标系间的位姿关系。针对工业机器人常见的地面式、侧墙式、顶棚式三种典型安装方式进一步分析了机器人基坐标系间的约束关系,并利用这些约束关系对标定结果做出进一步的优化处理。为验证提出的标定方法的有效性,基于Matlab的机器人工具箱完成了仿真实验,仿真实验的标定误差控制在2mm以内,该精度可满足一般弧焊、搬运、切割等生产过程的定位精度要求。仿真实验的结果验证了提出的标定方法的正确性,表明该方法可有效的解决生产环境下的协作机器人的基坐标系标定问题。     

基于手眼立体视觉的机器人定位系统

研发了基于手眼的机器人定位系统,采用了眼在手上的单目摄像机,通过机械手的一次移动实现了立体视觉的功能.提出了一种方便有效手眼标定方法,避免了复杂的传统手眼标定过程,无需求解摄像机外参数和手眼变换矩阵.仅获取标定时刻的摄像机综合参数和机器人位姿,就可以在机器人基坐标系中视场范围内的任意两点进行检测,根据立体视觉的约束关系求解出目标物体在机器人基坐标中的位置,进而实现对目标物体的精确定位.     

六自由度机器人焊接轨迹研究

焊接轨迹是机器人焊接时所行走的轨迹,焊接轨迹算法是控制机器人焊接轨迹的数学模型,本文提出一种通过测量机器人基坐标系、工件坐标系与测量系统坐标系的齐次变换矩阵方法,计算出工件坐标系与焊接机器人基坐标系间的间接标定方法,通过控制器系统控制机器人焊接,实验验证此方法正确可行并成功应用工程中。     

微操作机器人显微视觉系统的研究

本文深入研究了基于生物工程领域显微视觉系统的设计方法．给出了微操作物体平面坐标及微机器人手端位姿的求取方法；提出了基于载物台平动测量微操作物体的高度及微机器人做三维空间已知运动标定出微机器人手端在摄像机坐标系的坐标，进而确定微机器人手端与微操作物体之间位置关系的单目视觉方案．采用两步法对显微视觉系统进行了标定．实验证明该系统运行可靠，达到显微操作的要求．     

定点法扫描仪外部标定算法

研究了缺损零件的机器人快速再制造系统中，当机械手夹持扫描仪扫描固定的零件时，通过采用测量空间虚拟固定点的方法进行扫描仪外部标定算法的实现，即标定扫描仪的坐标系与机器人末端坐标系(即Tool0)间的旋转(即Rx, Ry, Rz)和平移(即X，Y，Z)关系，并给出了基本算法原理和求解方法、数据采集过程以及实验结果分析等内容。     

基于目标检测的机器人手眼标定方法

智能协作机器人依赖视觉系统感知未知环境中的动态工作空间定位目标,实现机械臂对目标对象的自主抓取回收作业。RGB-D相机可采集场景中的彩色图和深度图,获取视野内任意目标三维点云,辅助智能协作机器人感知周围环境。为获取抓取机器人与RGB-D相机坐标系之间的转换关系,提出基于yolov3目标检测神经网络的机器人手眼标定方法。将3D打印球作为标靶球夹持在机械手末端,使用改进的yolov3目标检测神经网络实时定位标定球的球心,计算机械手末端中心在相机坐标系下的3D位置,同时运用奇异值分解方法求解机器人与相机坐标系转换矩阵的最小二乘解。在6自由度UR5机械臂和Intel RealSense D415深度相机上的实验结果表明,该标定方法无需辅助设备,转换后的空间点位置误差在2 mm以内,能较好满足一般视觉伺服智能机器人的抓取作业要求。     

一种基于随动视觉的排爆机器人自主抓取系统

在传统基于固定视觉的排爆机器人抓取系统中,相机视觉易被遮挡且不能保证拍摄清晰度。基于随动视觉技术,提出一种将深度相机置于机械手末端并随机械手运动的排爆机器人自主抓取系统。利用深度相机计算目标物体的三维坐标,采用坐标转换方法将目标物体的位置坐标信息实时转换至机器人全局坐标系,并研究相机坐标系、机器人全局坐标系与末端执行器手爪工具坐标系三者的动态映射关系,实现排爆机器人的自主抓取。实验结果表明,与传统固定视觉方法相比,随动视觉方法可在误差2cm内,使得机器人机械手爪准确到达目标物体所在位置,且当机器人距离目标物体100cm~150cm时,抓取效果最佳。     

基于对偶四元数的机器人方位与手眼关系同时标定方法

针对相机姿态估计及机器人运动学正解存在测算偏差时,手眼标定及机器人坐标系-世界坐标系标定结果不能准确收敛到全局最优解的问题,提出了一种基于对偶四元数理论的机器人方位与手眼关系同时标定方法.该方法首先将标定方程中坐标系刚体变换关系用螺旋轴、旋转角度和平移量参数化表示,再结合全局优化算法对平移量进行优化.搭建了PUMA560机器人数值仿真系统和工业机器人实测实验平台,将该方法与经典的四元数和对偶四元数标定方法进行了比较分析.仿真和实测结果表明,在相机姿态估计及机器人运动学正解存在测量误差的情况下,该方法无需初值估计和数据筛选依然可以保证求解结果的最优性.     

一种新的机器人手眼关系标定方法

通过控制装有摄像机的机械手的运动，给出了一种新的机器人手眼系统标定方法．与以往算法的不同之处在于，在计算手眼关系的平移向量时，对摄像机坐标系进行虚设旋转变换使旋转转化为平移问题．该方法需要机械手平台做两次平移运动和一次旋转运动，只需要场景中两个特征点，所以具有方便性和实用性．同时，也给出了基于主动视觉的空间点深度值计算方法．     

A review on vision-based control of flexible manipulators

In this review, recent developments in the field of flexible robot arm control using visual servoing are reviewed. In comparison to rigid robots, the end-effector position of flexible links cannot be obtained precisely enough with respect to position control using kinematic information and joint variables. To solve the task here the use of a vision sensor (camera) system, visual servoing is proposed to realize the task of control flexible manipulators with improved quality requirements. The paper is organized as follows: the visual servoing architectures will be reviewed for rigid robots first. The advantages, disadvantages, and comparisons between different approaches of visual servoing are carried out. The using of visual servoing to control flexible robot is addressed next. Open problems such as state variables estimation as well as the combination of different sensor properties as well as some application-oriented points related to flexible robot are discussed in detail.     

Integrated distributed sensing and active vibration suppression of flexible manipulators using distributed piezoelectrics

Structural oscillation of flexible robot manipulators would severely hamper their operation accuracy and precision. This article presents an integrated distributed sensor and active distributed vibration actuator design for elastic or flexible robot structures. The proposed distributed sensor and actuator is a layer, or multilayer of piezoelectric material directly attached on the flexible component needed to be monitored and controlled. The integrated piezoelectric sensor/actuator can monitor the oscillation as well as actively and directly constrain the undesirable oscillation of the flexible robot manipulators by direct/converse piezoelectric effects, respectively. A general theory on the distributed sensing and active vibration control using the piezoelectric elements is first proposed. An equivalent finite element formulation is also developed. A physical model with distributed sensor/actuator is tested in laboratory; and a finite element model with the piezoelectric actuator is simulated. The distributed sensing and control effectiveness are studied.     

Markerless human–robot interface for dual robot manipulators using Kinect sensor

Remote teleoperation of robot manipulators is often necessary in unstructured, dynamic, and dangerous environments. However, the existing mechanical and other contacting interfaces require unnatural, or hinder natural, human motions. At present, the contacting interfaces used in teleoperation for multiple robot manipulators often require multiple operators. Previous vision-based approaches have only been used in the remote teleoperation for one robot manipulator as well as require the special quantity of illumination and visual angle that limit the field of application. This paper presents a noncontacting Kinect-based method that allows a human operator to communicate his motions to the dual robot manipulators by performing double hand–arm movements that would naturally carry out an object manipulation task. This paper also proposes an innovative algorithm of over damping to solve the problem of error extracting and dithering due to the noncontact measure. By making full use of the human hand–arm motion, the operator would feel immersive. This human–robot interface allows the flexible implementation of the object manipulation task done in collaboration by dual robots through the double hand–arm motion by one operator.     

Predictive control architecture for real-time image moments based servoing of robot manipulators

This paper presents a real-time architecture for visual servoing of robot manipulators using nonlinear based predictive control. In order to increase the robustness of the control algorithm, image moments were chosen to be the visual features which describe the objects from the image. A visual predictive architecture is designed to solve tasks addressed to robot manipulators with an eye-in-hand configuration. An implementation of the proposed architecture is done so that the capabilities of a 6 d.o.f robot manipulator are extended. The results of different experiments conducted with two types of image moments based controllers (proportional and predictive with reference trajectory) are presented and discussed.     

Joint-space orthogonalization and passivity for physical interpretations of dextrous robot motions under geometric constraints

A principle of ‘joint-space orthogonalization’ is proposed as an extended notion of hybrid (force and position) control for robot manipulators under geometric constraints. The principle realizes the hybrid control in a strict sense by letting position feedback signals be orthogonal in joint space to the contact force vector whose components exert at corresponding joints. This orthogonalization is executed via a projection matrix computed in real-time from a Jacobian matrix of the constraint equation in joint coordinates. To show the important role of the principle in control of robot manipulators, two basic set-point control problems are analysed. One is a hybrid PID control problem for robot manipulators under geometric endpoint constraint and another is a coordinated control problem of two arms. It is shown that passivity properties of residual dynamics of robots follow from the introduction of a quasi-natural potential and the joint-space orthogonalization. Various stability problems of PID-type feedback control schemes without compensating for the gravity force and with or without use of a force sensor are discussed from passivity properties of robot dynamics with the aid of the hyper-stability theory.     

基于知识库的输电线路巡检机器人的越障控制

介绍了一种高压输电线路巡检机器人越障控制方法。高压输电线路巡检机器人在翻越同一障碍物时重复同一套操作动作,可通过在实验室进行越障过程示教,离线学习形成操作知识库,实际越障时自动调用操作知识库并与在线信号相结合完成自主越障动作。讨论了知识库的一般组成和功能,并分析了激光传感器定位的方法以实现巡检机器人滚动轮与导线“对中”。经过实验验证,该控制方法具有稳定可靠,硬件结构简便,能可靠地完成控制任务,实现自主越障。     

On cooperative manipulation of dynamic objects

This paper proposes a decentralized position/internal force hybrid control approach for multiple robot manipulators to cooperatively manipulate an unknown dynamic object. In this approach, each autonomous robot has its own controller and uses its own sensor information in performing the fast cooperation. This approach eliminates a lot of information communications between each robot and reduces numerous computations. The influences of the position and the internal force estimation errors to the overall control system is analyzed. A cooperative identification method for each autonomous robot to identify the object's complex dynamics, cooperatively, is presented. In addition, the trade-off between the unilateral force constraint and the robots' position response is studied. Experiments show the effectiveness of this control approach.     

A systematic method of dynamics for flexible robot manipulators

In this article, a systematic method to derive dynamic equations of motion for flexible robot manipulators is developed by using the Lagrangian assumed modes method. The proposed method can be applied to dynamic simulation and control system design for flexible robot manipulators. In the proposed method, the link deflection is described by a truncated modal expansion. The operations of only 3x3 matrices and/or 3 × 1 vectors exist in the method. All the dynamics computations are performed in the link coordinate systems, where the kinematics informations are computed with the forward recursion from the base to the hand tip and the dynamics informations are computed with the return recursion. As generally compared with other existing methods, the method proposed in this article is, computationally, more simple, systematic, and efficient. A computational simulation for a single-link flexible robot manipulator is presented to verify the proposed method. © 1992 John Wiley & Sons, Inc.     

Adaptive Jacobian tracking control of rigid-link electrically driven robots based on visual task-space information

This paper studies stable adaptive tracking control of rigid-link electrically driven robot manipulators in the presence of uncertainties in kinematics, manipulator dynamics, and actuator dynamics. A new task-space control method using visual task-space information is proposed to overcome the uncertainties adaptively. Accelerations measurements are avoided in the control voltage inputs by constructing observers to specify desired armature currents. Simulation results illustrate the performance of the proposed control method.