机器人动态抓取的变比例导引路径规划方法

研究机器人手眼协调系统接近和抓取运动目标的路径规划方法,提出了一种脱胎于比例导引方法的变比例导引（ＶＧＰ）路径规划方法,这 方法设定手扑的视角在接近目标过程中以镁速不断变化,因而可以使手扑从目标运动前方拦截到目标,另外,机器人手扑在接近目标时,可以同时调整手主的接近姿态,以包抄的方式以目标。这种路径规划方法能够容许更大的目标位置估计误差,并能处理目标的机动运动,因而优于传统的目标跟踪路径规划方法,     

基于PH曲线的Delta机器人轨迹规划方法

针对Delta并联机器人高速作业时笛卡儿空间轨迹不平滑的问题,提出一种基于毕达哥拉斯速端曲线（PH曲线）的轨迹规划方法．首先,利用PH曲线平滑竖直运动与水平运动间的直角过渡部分,确定拾放操作轨迹;然后,利用多项式运动规律对轨迹的1维曲线位移进行规划,确定运动轨迹插补点的位置;最后,以最小化拾放操作周期为目标优化PH曲线参数,得到平滑的运动轨迹．仿真分析表明,基于该方法的拾放操作具有较短的运动周期,轨迹平滑且有较平稳的运动特性;实验结果表明,Delta机器人能够以90次/分钟的速度进行抓取操作,实现了并联机器人的高速作业．     

机器人多指手抓取中的规划问题

在机器人抓取系统中，一般认为需要４种规划器：即策略规划器，触觉规划器，轨迹规划抓取规划器，抓取规划器对成功抓取来说是非常重要的，在抓取规划器中，视觉模块用来把图象变换成物体的描述，接着用抓取模式选择模块把物体的描述换成一系列的控制信号，本文从最优抓取规划和基于专家系统的抓取规划这两个方面，着重从基于专家系统的抓取规划方面对当前机器人多指手抓取规划的研究现状及主要问题进行了深入地剖析。     

基于似人特性的拟人臂机器人自主抓取动作规划

针对拟人臂机器人在家庭环境中的自主抓取任务,提出了一种强调运动姿态似人特性的拟人臂动作的规划方法.该方法分为两个部分,构型规划和运动规划,构型规划基于人体工程学中广泛使用的快速上肢评估准则评价机器人运动姿态的似人特性,并在此基础上以机器人末端传速速率最优为目标规划机器人运动过程中的关键构型.运动规划结合了Fitts定律和似人运动模型规划了机器人末端的空间轨迹.本文最后以Motoman SDA10D拟人双臂机器人和Mitsubishi PA10机器人为例,具体介绍了该方法的应用和规划的结果,规划结果证明了本方法的可行性和有效性.     

面向传送带作业系统的机器人目标跟踪与抓取策略研究

运用机器视觉技术与工业机器人技术,开展传送带作业系统的机器人目标跟踪与动态抓取策略研究,提出了传送带速度控制的策略,建立了机器人抓取目标位置预测模型,在保证效率的同时降低了漏抓率;通过分析传送带PID跟踪控制规律,给出基于位置预测的机器人拦截式抓取方法,搭建了基于机器视觉的锯条自动抓取系统平台,开展机器人目标抓取对比实验分析,较好地实现了传送带作业系统机器人目标的动态抓取,有效验证了本文所提方法的可行性和有效性。     

一种采用迭代优化的移动抓取规划方法

提出了一种无需对目标物体进行预建模的迭代优化移动抓取规划方法.该方法通过点云相机在线对目标物体进行立体模型测量和建模,通过深度卷积神经网络对目标点云生成的多个候选抓取位置的抓取成功率进行评价.然后,对机器人底盘和手爪的位置和姿态进行迭代优化,直到抓取目标物体时机器人达到一个最优的位形.再用A*算法规划一条从机器人当前位置到目标位置的运动路径.最后,在路径的基础上,用一种启发式随机路径逼近算法规划手臂的运动,实现边走边抓的效果.本文的深度学习抓取成功率评估算法在康奈尔数据集上取得了83.3%的精确度.所提运动规划算法能得到更平滑、更短且更有利于后续运动的路径.     

排爆机器人控制与无线通讯系统

排爆机器人控制可分为小车的行走控制和机械手的运动控制。小车的行走控制需要进行“路程规划”以实现小车避障和向目标物(可疑爆炸物)靠近,而机械手的运动控制需要进行“轨迹规划”以避开障碍物实现避碰,顺利抓取、搬运目标物。此机器人控制系统是开放式系统,实现了智能化和网络化。远程管理机房电脑可以显示现场机器人手爪、目标物、障碍物。     

在线考虑运动学限制的最小加速度的轨迹规划

提出了一种基于简化运动规划的机器人轨迹规划新方法,可用于多自由度的机器人操作臂系统。关键问题是找到最小加速度的轨迹规划,来优化操作臂的运动以减少抖动。此外,给出了轨迹规划的解存在的充分必要条件,并考虑了所有的关节位置、角速度、加速度、加加速度等运动学限制。而且这种方法能够在线应用,适合任意非零的关节初始状态和目标状态,以便使机器人能够在运动过程中进行实时路径修正。最后提出的方法应用于一个七自由度的仿人机器人手臂来验证方法的有效性。     

机器人多指操作的递阶控制

为机器人多指协调操作建立一递阶控制系统.给定一操作任务,任务规划器首先生 成一系列物体的运动速度;然后,协调运动规划器根据期望的物体运动速度生成期望的手指 运动速度和期望的抓取姿态变化;同时,抓取力规划器为平衡作用在物体上的外力,根据当前 的抓取姿态,生成各手指所需的抓取力;最后,系统将手指的期望运动速度与为实现期望抓取 力而生成的顺应速度合并,并通过手指的逆雅可比转化为手指关节运动速度后,由手指的关 节级运动控制器实现手指的运动和抓取力的控制.该控制方法已成功应用于香港科技大学 (HKUST)灵巧手控制系统的开发.实验证明该方法不仅能完成物体轨迹的跟踪控制任务, 而且能完成物体对环境的力控制和力与速度的混合控制.     

基于虚拟位姿迟钝搜索的仿人机器人手臂抓取控制系统的设计

为了使仿人机器人手臂抓取控制系统更加智能化,提高运行效率,设计并实现了一种基于虚拟位姿迟钝搜索的仿人机器人手臂抓取控制系统。系统采用PMAC运动控制器完成机器人运行数据的传递、处理以及对机器人手臂抓取工作台的控制,采用Accelus系列数字伺服驱动器,调控仿人机器人运动位置和速度,通过关节控制器对机器人抓取过程中手臂关节的位置、速度以及角度信息进行控制,通过以S3C2440为核心芯片的上位机,实现仿人机器人手臂控制的远程通信以及抓取任务的调度,完成仿人机器人手臂抓取的智能控制,软件设计过程中,对基于虚拟位姿迟钝搜索的仿人机器人手臂抓取控制算法进行了详细分析,并给出了机器人手臂抓取控制程序代码实例,通过仿真实例验证了本系统的可用性和实用性。     

A new moving target interception algorithm for mobile robots based on sub-goal forecasting and an improved scout ant algorithm

It is difficult to make a robot intercept a moving target, whose trajectory and speed are unknown and dynamically changing, in a comparatively short distance when the environment contains complex objects. This paper presents a new moving target interception algorithm in which the robot can intercept such a target by following many short straight line trajectories. In the algorithm, an intercept point is first forecasted assuming that the robot and the target both move along straight line trajectories. The robot rapidly plans a navigation path to this projected intercept point by using the new ant algorithm. The robot walks along the planned path while continuously monitoring the target. When the robot detects that the target has moved to a new grid it will re-forecast the intercept point and re-plan the navigation path. This process will be repeated until the robot has intercepted the moving target. The simulation results have shown that the algorithm is very effective and can successfully intercept a moving target while moving along a relatively short path no matter whether the environment has complex obstacles or not and the actual trajectory of the moving target is a straight line or a complex curve.     

A Bezier curve based path planning in a multi-agent robot soccer system without violating the acceleration limits

This paper proposes an efficient, Bezier curve based approach for the path planning of a mobile robot in a multi-agent robot soccer system. The boundary conditions required for defining the Bezier curve are compatible with the estimated initial state of the robot and the ball. The velocity of the robot along the path is varied continuously to its maximum allowable levels by keeping its acceleration within the safe limits. An obstacle avoidance scheme is incorporated for dealing with the stationary and moving obstacles. When the robot is approaching a moving obstacle in the field, it is decelerated and deviated to another Bezier path leading to the estimated target position. The radius of curvature of the path at its end points is determined from the known terminal velocity constraint of the robot.     

Moving observer trajectory control by angular measurements in tracking problem

An optimal path synthesis problem for a moving observer that performs angular observations over a target moving uniformly along a straight line on a plane is solved. It is supposed that elevation and azimuth angles can be observed when the observer moves in space and only the azimuth angle can be observed when the observer moves on a plane. Observer’s trajectories are obtained with the help of Pontryagin’smaximum principle as numerical solutions of an optimal control problem. As a performance criterion the trace of covariance matrix of the target motion elements estimate is used. A possibility of solving the problem in real time on board for unmanned aerial vehicle is investigated. A comparison with the scenario of two unmanned aerial vehicles using is given.     

On-line Planning for Collision Avoidance on the Nominal Path

In this paper a solution to the obstacle avoidance problem for a mobile robot moving in the two-dimensional Cartesian plane is presented. The robot is modelled as a linear time-invariant dynamic system of finite size enclosed by a circle and the obstacles are modelled as circles travelling along rectilinear trajectories. This work deals with the avoidance problem when the obstacles move in known trajectories. The robot starts its journey on a nominal straight line path with a nominal velocity. When an obstacle is detected to be on a collision course with the robot, the robot must devise a plan to avoid the obstacle whilst minimising a cost index defined as the total sum squared of the magnitudes of the deviations of its velocity from the nominal velocity. The planning strategy adopted here is adjustment of the robot's velocity on the nominal path based on the time of collision between the robot and a moving obstacle, and determination of a desired final state such that its Euclidean distance from the nominal final state is minimal. Obstacle avoidance by deviation from the nominal path in deterministic and random environments is based on the work presented here and is investigated in another paper.     

Stabilization of a Cart with Inverted Pendulum

Automation and Remote Control - We consider the problem of stabilizing a cart moving along a straight line with an inverted pendulum installed on it. The control objective is to stabilize the cart...     

A Coordinated Navigation Strategy for Multi-Robots to Capture a Target Moving with Unknown Speed

The paper proposes an algorithm for multi-robot coordination and navigation in order to intercept a target at a long distance. For this purpose, a limit cycle based algorithm using a neural oscillator with phase differences is proposed. The state of target is unknown, under the assumption that it is stationary or in motion with constant unknown speed along a straight line. Using the proposed algorithm, a group of robots is intended to move towards the target in such a way that the robots surround it. While moving to the target, self-collision between the robots is avoided. Moreover, a collision avoidance with static obstacles as well as dynamic target is realized. The robots reach the target at a desired distance, keeping uniformly distributed angles around the target. The algorithm is further extended so that a static interception point for the target can be estimated in place of pursuing a dynamic target, which is referred to as a virtual target in this paper. In other words, the robots move towards the virtual target instead of the actual target. The robots ultimately encircle the actual target when they arrive at the virtual target. The effectiveness of the proposed method is verified through simulation results.     

Trajectory triangulation: 3D reconstruction of moving points from amonocular image sequence

We consider the problem of reconstructing the 3D coordinates of a moving point seen from a monocular moving camera, i.e., to reconstruct moving objects from line-of-sight measurements only. The task is feasible only when some constraints are placed on the shape of the trajectory of the moving point. We coin the family of such tasks as “trajectory triangulation.” We investigate the solutions for points moving along a straight-line and along conic-section trajectories, We show that if the point is moving along a straight line, then the parameters of the line (and, hence, the 3D position of the point at each time instant) can be uniquely recovered, and by linear methods, from at least five views. For the case of conic-shaped trajectory, we show that generally nine views are sufficient for a unique reconstruction of the moving point and fewer views when the conic is of a known type (like a circle in 3D Euclidean space for which seven views are sufficient). The paradigm of trajectory triangulation, in general, pushes the envelope of processing dynamic scenes forward. Thus static scenes become a particular case of a more general task of reconstructing scenes rich with moving objects (where an object could be a single point)     

C-velocity: A cumulative frame to segment objects from egomotion

This paper deals with extracting 3D-planar structures of a moving scene from a 2D-image sequence. The camera is assumed on board a vehicle moving straight so that the dominant apparent motion generates a scale change along images. We introduce the concept of c-velocity space. That is a cumulative frame in which planar surfaces are transformed into straight lines. Equations ruling the phenomenon are given and explained. Then results on synthetic images are shown to meet the theory. Eventually results on real data are commented on as for the uncertainty introduced by the location of the FOE and other types of noise. The article is published in the original.     

A pseudo dual-cavity extrinsic fibre Fabry-Pérot interferometric vibrometer

An extrinsic fibre Fabry-Pérot interferometric (EFFPI) sensor for the measurement of velocity and displacement of a vibrating target has been demonstrated in this work. It operates on the principle of a pseudo-double cavity within a single interferometric or “sensing” arm which, in addition, provides a sense of direction of the moving target. This has been made possible by the introduction of a birefringent film positioned along the optical path between the sensing fibre end and the intended target. Two sets of interference signals are thus propagated and detected along one fibre arm to give robust and repeatable displacement–velocity information which have been found to be relatively independent on other external effects such as minor temperature changes. The sensor has been found to be capable of measuring the desired velocity information of an inclined target while typical excitation frequencies investigated ranged from 2 to 60 Hz. In addition, two sensor configurations have been studied, one based on “conventional” optical fibres at 780 nm while the other employs a polarisation-maintaining (PM) (PANDA type) fibre as the sensing arm and operates at 1310 nm.     

多重约束条件下的LBD描述子与直线段匹配

目的 针对直线描述子匹配算法缺乏有效的几何约束,且易受弱纹理、尺度变化的影响,提出一种结合多重约束条件的LBD描述子的直线段匹配算法（LBDs）。方法 该算法以LSD算法提取的直线段作为匹配基元,利用SIFT匹配得到的同名点构建同名三角网约束确定候选直线;参考影像上以目标直线段为中心轴建立该直线段的矩形支撑域;根据目标直线段端点及其支撑域四角点在搜索影像上的核线约束建立候选直线段的对应支撑域;利用仿射变换统一目标直线段及候选直线段支撑域的大小;将直线段支撑域分解为大小相等的条形带,通过计算每个条形带的描述符得到该直线段的描述子,依次完成目标直线段与候选直线段LBD描述子的构建;分别计算目标直线段与每个候选直线段描述子向量间的欧氏距离,将满足最近邻距离比准则的候选直线段作为匹配结果;最后选取角度约束对匹配结果检核,确定同名直线。结果 实验选取网上公开的3组分别存在角度、旋转、尺度变换的近景影像对作为实验数据,采用LBDs分别对其进行直线段匹配实验,并与其他直线段匹配算法进行对比分析,实验结果表明,LBDs获取同名直线数目约为其他算法的1.061.41倍,匹配正确率也提高了2.411.6个百分点,从匹配效率上来看,LBDs更为耗时,但兼顾该算法匹配获得同名直线数目、匹配正确率及运行时间,LBDs的鲁棒性更强,匹配结果的准确性与可靠性较高。结论 结合多重约束条件构建的LBD描述子对于存在角度、旋转和尺度变化的影像进行直线匹配过程中具有稳定性。