共查询到20条相似文献,搜索用时 15 毫秒
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水下仿生软体机器人在水底环境勘测, 水下生物观测等方面具有极高的应用价值. 为进一步提升仿章鱼臂软体机器人在特殊水下环境中控制效果, 提出一种自适应鲁棒视觉伺服控制方法, 实现其在干扰无标定环境中的高精度镇定控制. 基于水底动力学模型, 设计保证动力学稳定的控制器; 针对柔性材料离线标定过程繁琐、成本高, 提出材料参数自适应估计算法; 针对水下特殊工作条件, 设计自适应鲁棒视觉伺服控制器, 实现折射效应的在线补偿, 并通过自适应未知环境干扰上界, 避免先验环境信息的求解. 所提算法在软体机器人样机中验证其镇定控制性能, 为仿生软体机器人的实际应用提供理论基础. 相似文献
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基于图像的视觉伺服方法,图像的变化直接解释为摄像机的运动,而不是直接对机械手末端实现笛卡尔速度控制,导致机械手的运动轨迹迂回,产生摄像机回退现象.针对这一问题,提出了将旋转和平移分离并先实现旋转的视觉伺服方案.该方案计算量小,系统响应时间短,解决了图像旋转和平移间的干扰,克服了传统基于图像视觉伺服产生的摄像机回退现象,实现了时间和路径的最优控制.并用传统IBVS的控制律和摄像机成像模型解释了回退现象的产生原因.二维运动仿真说明了提出方案的有效性. 相似文献
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针对移动机器人视觉伺服跟踪控制问题, 提出一种基于自适应动态规划(Adaptive dynamic programming, ADP) 的控制方法. 通过移动机器人上的相机拍摄共面特征点的当前图像、期望图像以及参考图像, 利用单应性技术得到移动机器人当前的位姿信息与期望的位姿信息(即平移量与旋转角度), 从而通过当前与期望的平移旋转之间差值得到系统的开环误差模型. 进而, 针对此系统设计最优控制器, 同时做合适的控制输入变换. 在此基础上设计一个基于ADP的视觉伺服控制方法以保证移动机器人完成轨迹跟踪任务. 为求出最优控制输入, 采用一个评价神经网络近似值函数, 通过不断学习逼近哈密顿−雅可比−贝尔曼(Hamilton-Jacobi-Bellman, HJB)方程的解. 与以往不同的是, 由于系统存在时变项, 导致HJB方程也含有时变项, 因此需要设计具有时变权值结构的神经网络近似值函数. 最终证明在所设计的控制方法作用下, 闭环系统是一致最终有界的. 相似文献
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We consider a robotic setting and a class of control tasks that rely on partial visual information. These tasks are difficult in the sense that at every given moment, the available information is insufficient for the control task. This implies that the image Jacobian, which relates the image space and the control space, is no longer of full rank. However, the amount of information collected throughout the control process is still large and thus seems sufficient for carrying out the task. Such situations commonly arise when the object is frequently occluded from one of the cameras in a stereo pair or when only one moving camera is available. We propose a generic control rule for such tasks and characterize the conditions required for the success of the task. The analysis is based on the observation that mathematically the behavior of such systems is related to a class of row-action optimization algorithms which are special cases of POCS (Projection On Convex Sets) algorithms. In the second part of the paper we focus on one particular task from this class: position and orientation control with a single rotating camera. We show that this task can be carried out, in principle, for any camera rotation and suggest efficient control and camera moving strategies. We substantiate our claims by simulations and experiments. Interestingly, it seems that the advisable control law is not consistent with simple intuition. 相似文献
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This paper presents a novel approach for image‐based visual servoing (IBVS) of a robotic system by considering the constraints in the case when the camera intrinsic and extrinsic parameters are uncalibrated and the position parameters of the features in 3‐D space are unknown. Based on the model predictive control method, the robotic system's input and output constraints, such as visibility constraints and actuators limitations, can be explicitly taken into account. Most of the constrained IBVS controllers use the traditional image Jacobian matrix, the proposed IBVS scheme is developed by using the depth‐independent interaction matrix. The unknown parameters can appear linearly in the prediction model and they can be estimated by the identification algorithm effectively. In addition, the model predictive control determines the optimal control input and updates the estimated parameters together with the prediction model. The proposed approach can simultaneously handle system constraints, unknown camera parameters and depth parameters. Both the visual positioning and tracking tasks can be achieved desired performances. Simulation results based on a 2‐DOF planar robot manipulator for both the eye‐in‐hand and eye‐to‐hand camera configurations are used to demonstrate the effectiveness of the proposed method. 相似文献
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一种拟人空间机械臂视觉伺服图像处理研究 总被引:1,自引:0,他引:1
针对四自由度串并混联拟人空间机械臂本体,构建了基于运动控制卡模式的机器人软件和硬件系统。采用基于位置的控制结构,利用所求得的机械臂逆运动学方程,设计了由图像反馈和末端运动组成的视觉伺服控制系统。提出了一种基于SURF特征的静态目标识别算法,算法首先对目标图像提取SURF特征,并利用欧氏距离实现模板图像与目标图像特征点匹配,然后计算已匹配特征点的质心来获得目标的位置信息,最终实现了稳定的伺服定位。实验结果证明了系统的可靠性,并且证明了四自由度串并混联机械臂本体在实际运动的精确性和稳定性。 相似文献
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当末端带有相机的连续型软体机器人进行作业时,由于避障、安全性等多方面因素,既需要末端相机-机器人系统的视觉伺服,也需要机器人的整体形状控制.针对这个问题,本文提出了一种软体机器人手眼视觉/形状混合控制方法.该方法无需知道空间特征点的3维坐标,只需给定特征点在末端相机像平面的期望像素坐标和软体机器人的期望形状就可达到控制目的.建立了软体机器人的运动学模型,利用该模型,结合深度无关交互矩阵自适应手眼视觉控制和软体机器人形状控制,提出了一种混合控制律,并用李亚普诺夫稳定性理论对该控制律进行证明.仿真和实验的结果均表明,末端相机特征点像素坐标和形状可以收敛到期望值. 相似文献
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Visual Object Tracking and Servoing Control of a Nano-Scale Quadrotor: System,Algorithms, and Experiments 下载免费PDF全文
There are two main trends in the development of unmanned aerial vehicle(UAV)technologies:miniaturization and intellectualization,in which realizing object tracking capabilities for a nano-scale UAV is one of the most challenging problems.In this paper,we present a visual object tracking and servoing control system utilizing a tailor-made 38 g nano-scale quadrotor.A lightweight visual module is integrated to enable object tracking capabilities,and a micro positioning deck is mounted to provide accurate pose estimation.In order to be robust against object appearance variations,a novel object tracking algorithm,denoted by RMCTer,is proposed,which integrates a powerful short-term tracking module and an efficient long-term processing module.In particular,the long-term processing module can provide additional object information and modify the short-term tracking model in a timely manner.Furthermore,a positionbased visual servoing control method is proposed for the quadrotor,where an adaptive tracking controller is designed by leveraging backstepping and adaptive techniques.Stable and accurate object tracking is achieved even under disturbances.Experimental results are presented to demonstrate the high accuracy and stability of the whole tracking system. 相似文献
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A Modular Scheme for Controller Design and Performance Evaluation in 3D Visual Servoing 总被引:1,自引:0,他引:1
M. Bachiller J. A. Cerrada C. Cerrada 《Journal of Intelligent and Robotic Systems》2003,36(3):235-264
In this paper we present a modular scheme for designing and evaluating different control systems for position based dynamic look and move visual servoing systems. This scheme is particularly applied to a 6 DOF industrial manipulator equipped with a camera mounted on its end effector. The manipulator with its actuators and its current feedback loops can be modeled as a Cartesian device commanded through a serial line. In this case the manipulator can be considered as a decoupled system with 6 independent loops. The use of computer vision as feedback transducer strongly affects the closed loop dynamics of the overall system, so that a visual controller is required for achieving fast response and high control accuracy. Due to the long delay in generating the control signal, it is necessary to carefully select the visual controller. In this paper we present a framework that allows the study of some conventional and new techniques to design this visual controller. Besides an experimental setup has been built and used to evaluate and compare the performance of the position based dynamic look and move system with different controllers. Some criterions for selecting the best strategy for each task are established. Quite a lot of results relative to different trajectory tracking control strategies are presented, showing both simulation and real platform responses. 相似文献
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以二自由度平面机器人为研究对象,将FCMAC控制方法应用到基于图像的机器人视觉伺服系统中.建立了系统的数学模型,并在Matlab平台上对该系统进行仿真实验.仿真结果表明,本文的控制系统对静态目标定位、对直线运动目标及曲线运动目标进行跟踪,可以获得较快的响应速度和较高的控制精度. 相似文献
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This paper presents the application of the Visual Servoing approach to a mobile robot which must execute coordinate motions in a known indoor environment. In this work, we are interested in the execution and control of basic motions like Go to an object by using the mobile robot Hil are2Bis. We use a diagonal matrix for the gain to improve the visual servoing behaviour and the potential field formalism to avoid obstacles. Namely, the robot is controlled according to the position of some features in an image. Such a path will be executed by a nonholonomic mobile robot, which has only two degrees of freedom (two wheels), and three configuration parameters (X Y ); a camera is mounted on the robot close to the end effector of an arm, controlled to add at least a new degree of freedom (pl). 相似文献