基于改进比例导引法的机器人动态避障算法

随着机器人运动环境日益复杂,为了使机器人可以安全、有效地避开动态障碍到达目的地,提出一种基于改进比例导引法的机器人动态避障算法;首先借助比例导引法的思想,通过使机器人与动态障碍物的相对速度方向导引到避障向量方向完成避障,然后为满足避障完成时间和机器人机动性能约束要求,得到重叠比例导引系数取值范围,并采用比例导引法对机器人运动路径进行规划到达目的地,最后采用仿真实验测试其有效性;仿真结果表明,该算法可以使机器安全有效地避开动态障碍物,对机器人的实际运动轨迹控制具有一定的参考价值.     

基于聚类分析和运动描述语言的扑翼飞行机器人行为规划

为了解决扑翼飞行机器人实时控制过程中操作者工作量大、操作较为复杂的难题,实现扑翼飞行机器人的分布式智能控制,提出了基于聚类分析和运动描述语言的扑翼飞行机器人行为规划方法.利用扑翼飞行机器人飞行数据聚类分析的结果,将机器人运动行为进行合理分类.在保证了运动描述语言的基元关系的同时,合理提取了扑翼飞行机器人的行为特征,并针对扑翼飞行机器人绕杆任务定义了4类运动基元.以扑翼飞行机器人和机载陀螺仪搭建了扑翼飞行机器人实验系统.通过直接控制方法和基于运动描述语言的机器人行为规划方法进行了实物实验和仿真实验,实验结果验证了所提方法的可行性和有效性.     

一种混合路径规划方法在轮式机器人中的应用*

针对目前机器人在局部路径规划和全局路径规划中存在的问题,提出了一种混合路径规划方法,构建了机器人运动模型与障碍物扩展模型,机器人在栅格地图上沿全局规划路径向目标点移动时,在线实时规划出局部临时目标点以避开探测到的障碍物。最后证明了该规划方法的时间收敛性,并在双轮差速驱动机器人Pioneer 3-DX实验平台上验证了方法的有效性。     

基于滑移矩阵的铺管路径规划与导引控制方法.

为了实现深水海洋管道的连续铺管作业、满足铺管的路径和导引信息的自动更等新要求,提出了一种基于滑动矩阵的路径分析、路径映射与路径导引的方法,建立了一种基于铺管接触距离的管道路径和船舶路径的映射关系,给出了一种适合动力定位铺管船的曲线路径跟踪的LOS视线导引算法,设计了一种船舶位置、姿态和速度控制的多目标铺管运动控制器。海洋连续铺管仿真作业的结果表明：本方法可在风浪流的环境干扰下,实现连续铺管作业过程中的路径自动识别、自动规划、自动导引和位置控制等目标,同时满足铺管速度和航向角等控制要求,对于船舶动力定位和水下机器人运动的路径规划和导引控制方法的研究具有较强的理论意义和工程价值。     

基于惩罚函数NPGA的多目标路径规划

通过分析传统的机器人路径规划方法,将足球机器人路径规划归结为一个多目标优化问题,利用基于惩罚函数的小生境遗传算法建立动态目标路径规划的运动模型.仿真表明,与传统的路径规划方法相比,该方法在保证机器人较高体力值的前提下,规划出合理的路径.     

人工蜂群算法在移动机器人路径规划中的应用

研究机器人路径规划优化问题,机器人工作环境复杂,运动路径上存在许多障碍物.针对提高机器人安全导航性能问题,传统群智能算法存在早熟、搜索效率低等难题,难以获得全局最优路径.为了获得最优机器人运动路径,避免碰撞的发生,提出了一种人工蜂群算法的机器人路径规划方法.首先采用栅格法对机器人工作环境进行建模,然后机器人路径规划目标点作为蜜源,最后蜂群之间信息交换、协作搜索最优机器人运动路径.结果表明,人工蜂群算法解决了传统群智能算法存在的难题,加快了机器人路径规划求解速度,以较短时间找到最短机器人运动路径.     

基于平行接近法的对运动目标跟踪的研究

移动机器人可以对运行目标进行跟踪,但机器人跟踪目标的路线的知短对机器人的运动效果有很大影响,因此找一条机器人运行的最优路线是很重要的,本文把导弹追踪的一种自动导引方法－平行接近法应用到机器人对目标的跟踪中,以期用最少的时间和用最短的路线来追踪到目标。     

空间自由漂浮机器人对运动目标抓捕的路径规划

针对空间机械臂对运动目标的抓捕提出了一种分段的在线运动规划方法,重点解决机械臂可能遮挡立体视觉相机视线的问题,并满足抓捕时间要求.基于扩展卡尔曼滤波器(EKF)建立了目标运动状态估计器.对立体视觉相机的视线遮挡约束进行了数学建模.将机械臂向目标的接近过程分成2个阶段,在2个阶段中分别使用多约束环境下的滚动RRT(快速扩展随机树)方法和能够快速接近目标的比例导引算法,并根据对目标运动状态的估计精度自主切换运动段.同时考虑组合体的动力学耦合特性,在运动规划中限制了平台姿态角速度.利用数学仿真验证了本文的目标运动状态估计方法和运动规划方法.比例导引方法可能由于机械臂遮挡立体视觉相机观测视线而抓捕失败,而本文的分段运动规划方法对全部仿真情况都能成功抓捕目标.本文的分段运动规划方法能够对各个方向运动的目标进行有效的运动状态估计并快速可靠地抓捕,避免了因遮挡立体视觉相机观测视线引起的抓捕失败.基于目标运动状态估计的切换策略能够根据实际的目标运动情况在线自主地切换2个运动段,对运动状态未知的目标具有鲁棒性.     

未知环境下基于椭圆约束的机器人路径规划

针对未知环境下机器人路径规划问题,提出一种基于椭圆约束的路径规划方法。借助椭圆约束规划路径,将路径规划问题转化为椭圆参数优化问题。通过建立椭圆约束优化模型,引入障碍物和目标位置的约束,考虑机器人运动步长及运动方向的影响,实现复杂未知环境下机器人路径规划。基于不同算法的仿真实验结果表明,该方法有效解决了未知环境下机器人路径规划问题,在大量障碍物存在的未知环境,也能快速有效地进行无碰撞路径规划。     

基于比例导引的足球机器人截球算法研究

常用的足球机器人截球运动控制算法较少,通过类比机器人截球运动与导弹或鱼雷追踪目标的相似性,引入军事目标追踪导引算法中常用的比例导引算法,并给出了导引算法模型及其在足球机器人系统中的应用实现。仿真结果表明该算法效果明显,行之有效,并能够根据不同的应用要求灵活的调整导引系数,取得比较理想的截球控制效果。     

Grasping and in-hand manipulation: experiments with a reconfigurable gripper

This paper addresses the problem of grasping and manipulating three-dimensional objects with a reconfigurable gripper equipped with two parallel plates whose distance can be adjusted by a computer-controlled actuator. The bottom plate is a bare plane and the top one carries a rectangular grid of actuated pins that can translate in discrete increments under computer control. We propose to use this gripper to immobilize objects through frictionless contacts with three of the pins and the bottom plate, and to manipulate an object within a grasp by planning the sequence of pin configurations that will bring this object to a desired position and orientation. A detailed analysis of the problem geometry in configuration space was used in a previous paper to devise simple and efficient algorithms for grasp and manipulation planning. We have constructed a prototype of the gripper and this paper presents our experiments.     

Visibility-based spatial reasoning for object manipulation in cluttered environments

In this paper, we present visibility-based spatial reasoning techniques for real-time object manipulation in cluttered environments. When a robot is requested to manipulate an object, a collision-free path should be determined to access, grasp, and move the target object. This often requires processing of time-consuming motion planning routines, making real-time object manipulation difficult or infeasible, especially in a robot with a high DOF and/or in a highly cluttered environment. This paper places special emphasis on developing real-time motion planning, in particular, for accessing and removing an object in a cluttered workspace, as a local planner that can be integrated with a general motion planner for improved overall efficiency. In the proposed approach, the access direction of the object to grasp is determined through visibility query, and the removal direction to retrieve the object grasped by the gripper is computed using an environment map. The experimental results demonstrate that the proposed approach, when implemented by graphics hardware, is fast and robust enough to manipulate 3D objects in real-time applications.     

Grasping and In-Hand Manipulation: Geometry and Algorithms

This paper addresses the problem of grasping and manipulating three-dimensional objects with a reconfigurable gripper that consists of two parallel plates whose distance can be adjusted by a computer-controlled actuator. The bottom plate is a bare plane, and the top plate carries a rectangular grid of actuated pins that can translate in discrete increments under computer control. We propose to use this gripper to immobilize objects through frictionless contacts with three of the pins and the bottom plate, and to manipulate an object within a grasp by planning the sequence of pin configurations that will bring this object to a desired position and orientation. A detailed analysis of the problem geometry in configuration space is used to devise simple and efficient algorithms for grasp and manipulation planning. The proposed approach has been implemented and preliminary simulation experiments are discussed. Received November 15, 1996; revised February 4, 1998.     

Multisensor controlled robot system for recognizing and tracking moving multiple objects

This paper presents a cost-efficient, real-time vision-sensor system for identifying, locating and tracking objects that are unknown and randomly placed on a moving conveyor belt. The visual information obtained from a conventional frame-store unit and an end-effector based proximity sensor outputs are incorporated in a fuzzy-logic control algorithm to make the robotic manipulator grasp moving objects. The robot movements are going to be the result of the comparative measurements made by the sensors after the motion of the moving target is predicted and the gripper is brought into a zone close to the object to be grasped by the application of a vision system. The mobile object is traced by controlling the motion of the end-effector with an end-effector based infrared proximity sensors and conveyor position encoder by keeping the gripper's axis to pass through a median plane of the moving object. With this procedure and using the fuzzy-logic control, the system is adapted to pursue of a mobile object. Laboratory experiments are presented to demonstrate the performance of this system. ©1999 John Wiley & Sons, Inc.     

Static grip selection for robot-based automated assembly systems

In this article we present an algorithmic approach to determine the suitable grasp of an object in an automated assembly environment. The algorithm is based on the available object surfaces and the initial and final task constraints and gripper characteristics. If the imposed task and gripper constraints do not allow a possible grasp, intermediate motions may need to be made to reorient the part. Once a set of possible grasps which statisfy task and gripper constraints are found, the stability of each grasp is analyzed using screw theory. An optimal grasp is one which minimizes the grasping forces over the possible set of grasps. Results utilizing our methodology are presented. Our method can be interfaced with CAD database such as a solid modelling system based on boundary representation for automatic selection of grasping configurations.     

抓取任务中的融差控制方法

依据“融差性思维”,提出了无需精确感知依旧可以在一定范围内有效工作的融差控制方法。具体分析了融差抓取方法如何运用相同控制量实现不同抓取任务的工作原理,这一原理使得融差抓取方法在面对一大类抓取任务时,不需要知道物体的具体参数,只需要知道这一大类物体的边界条件。进一步分析了融差抓取方法在欠驱动手爪上的适用性,并发现了欠驱动手爪的局限性。实验表明,在控制量设定不变的情况下,依据融差抓取方法,柔性手爪可以抓住且不抓坏宽度范围为5～45 mm的嫩豆腐,且能够成功抓取宽度范围为5～60 mm的硬质长方体;弹簧关节欠驱动手爪可以抓住且不抓坏宽度范围为20～40 mm的嫩豆腐,且能够成功抓取宽度范围为5～60 mm的硬质长方体。这体现了融差抓取方法的通用性和欠驱动手爪在抓取柔性物体时的局限性。最后,展示了柔性手爪使用融差抓取方法在桌面抓取应用中以简单的控制策略成功抓取不同形状、不同材质的物体。这充分说明了融差抓取方法不依赖于精确的对象感知及物体模型,能够简化控制策略。     

Pick-and-verify: verification-based highly reliable picking system for various target objects in clutter

The reliability of picking task for various objects in clutter, as measured on the Amazon Picking Challenge, is far from the expectations of automation companies. Even if the best-performed team, who run object detection before picking the object, had picked a wrong object in the competition. In this paper, we propose a practical method to compose a highly reliable picking system with verification-based approach to reduce the rate of wrong picking and raise the reliability of picking ordered objects. In our approach, which we call pick-and-verify, the robot recognizes object twice: in clutter scene to detect the target and in hand after picking an object with less time loss and rise of reliability of picking the target. For grasping the detected object we do not assume its pose and it is actually the target object, instead, we adopt vision-based grasp planning for vacuum gripper with sensed 3-D point cloud. With the presented approach, the reliability of picking target objects raised 50%, and the score in the APC2015 competition has been improved to be close to the best-performed team by picking 9 out of 12 objects in 10 min with the same hardware in our previous system.     

Motion Planning for Two Robots of an Object Handling System Considering Fast Transition Between Stable States

Fast transition from a stable initial state to a stable handling state is important when multiple mobile robots grasp and transport a bulky and heavy object. In this paper, we present motion planning for two robots of an irregularly shaped object handling system considering fast transition between stable states. A cooperative object handling system consisting of a gripper robot equipped with a gripper and a lifter robot equipped with a lifter was first designed. Then, a strategy to realize fast transition between stable states by using the object handling system designed was proposed. While grasping and lifting an object off the ground, a gripper robot grasps and lifts up the object from one side to provide enough space for a lifter robot to lift the object off the ground cooperatively. Fast transition between stable states is formulated as a constraint optimization problem. The goal is to realize transition from a stable initial state to a stable handling state in a minimal amount of time. Experiments involving two robots and everyday objects were conducted. The two robots cooperatively obtained fast transition between stable states. The results illustrate the validity of the proposed method.     

基于图像误差的机器人运动目标自适应跟踪

讨论了机械手运动目标跟踪问题，直接利用图像误差达到注视目的。利用手部摄像机于期望位置获取待跟踪物体图像，以此作为期望图像，而后可以对同为运动物体进行注视跟踪，使实时采样图像收敛于期望图像。     

Proportional navigation guidance for robotic interception of moving objects

Two novel navigation‐guidance‐based methods are presented for on‐line‐robotic‐interception of fast‐maneuvering objects. For the first method, an ideal proportional navigation‐guidance (IPNG) technique is used during phase I of the two‐phase robot trajectory planning and control strategy. For the second method, an augmented form of the IPNG (AIPNG) technique is suggested for phase I, when a reliable estimation of the acceleration of the target can be provided to the interceptor. Both techniques are modified to reflect the greater mobility of a robotic manipulator over an airborne interceptor. The convergence analyses of both methods are detailed and compared to that of a conventional moving‐object tracking method. Computer simulations clearly illustrate the effectiveness of the IPNG‐based interception methods over pure tracking‐based techniques proposed in the cited literature. © 2000 John Wiley & Sons, Inc.