共查询到18条相似文献,搜索用时 797 毫秒
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机器人多指手协调操作物体时,合理地确定手指对被操作物体的作用力是必要的.本文将手指尖与被操作物体之间接触模拟为具有摩擦的点接触,对由多指手与被操作物体组成的这样一个速度较低的系统作了静力分析,并对多指手操作物体时的操作力作了合理的分配,提出基于力矩最小的内力的最优计算方法,在计算中,充分考虑到手指只能推而不能拉物体这一实事.最后,以4个手指操作一个圆柱形物体为例.对操作过程作了图形仿真. 相似文献
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三指机器人手的运动学研究 总被引:2,自引:0,他引:2
本文研究了指端与物体间为纯滚动接触时三指9关节机器人手操作物体的运动学问题,建立了手指关节运动与物体运动之间的位置关系、速度关系和加速度关系,给出了9个节间的运动约束条件。 相似文献
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《机器人技术与应用》2006,(4):43-43
由哈尔滨工业大学机器人研究所与德国宇航中心合作开发的具有多种传感功能的新一代机器人灵巧手在哈尔滨问世。该灵巧手有4个手指,13个自由度,其中每个手指有4个关节、3个自由度,拇指另有一个开合的自由度:灵巧手共有机械零件600多个.表面粘贴的电子元器件1600多个,传感器89个:手的尺寸略大于人手,整体重量1.8千克。灵巧手可以弹出美妙的音乐,可以轻松地抓起饮料瓶.也可以灵活地做出“OK”的手势。到目前为止.已经有5套仿人灵巧手销往德国。 相似文献
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机器人多指手灵巧抓持规划 总被引:8,自引:1,他引:8
抓持规划是机器人灵巧手要完成预期任务所面临的一个重要问题.本文采用主从操作方式进行灵巧手的指尖抓持规划,由人手决定抓持接触点的位置, 灵巧手通过调整其手掌的位置和姿态保证各手指在人手指定的位置上抓持物体.根据灵巧手的操作特点,提出以关节灵活度来描述关节运动各向同性的能力,并据此定义灵巧手操作灵活度,作为灵巧手抓持位形性能的评价指标.以最大操作灵活度作为优化目标函数,寻求最优的抓持性能.同时,借鉴人手的抓持经验,通过主从操作方式,建立从人手到灵巧手的运动映射关系,从而为手掌位置优化问题提供合理的初值.仿真实验结果说明了文中方法的有效性. 相似文献
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This article presents an expository work on a differential-geometric treatment of fundamental problems of 2D and 3D object grasping and manipulation by a pair of robot fingers with multi-joints under holonomic or nonholonomic constraints. First, Lagrange’s equation of motion of a fingers-object system whose motion is confined to a vertical plane is derived under holonomic constraints when rolling contacts between finger-ends and object surfaces are permitted. Then, a class of control signals called “blind grasping” and constructed without knowing the object kinematics or using any external sensing like vision or tactile sensation is shown to realize stable object grasping in a dynamic sense. Stability of motion and its convergence to an equibrium manifold are treated on the basis of differential geometry of solution trajectories of the closed-loop dynamics on the constraint manifolds. Second, a mathematical model of 3D object grasping and manipulation by a pair of multi-joint robot fingers is derived under the assumption that spinning motion of rotation around the opposing axis between contact points does no more arise. It is shown that, differently from the 2D case, the instantaneous axis of rotation of the object is time-varying, which induces a nonholonomic constraint expressed as a linear differential equation of rotational motion of the pinched object. It is shown that there is a class of control signals constructed without knowing the object kinematics or using external sensings that can realize “blind grasping” in a dynamic sense. Finally, it is shown that the proposed differential geometric treatment of stability can naturally cope with redundancy resolution problems of surplus degrees-of-freedom (d.f.) of the overall fingers-object system, which is closely related to Bernstein’s d.f. problem. 相似文献
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This paper shows that a pair of dual multi‐DOF fingers with soft‐tips can learn iteratively a desired periodic motion of manipulation of an object if sensory feedback signals are designed adequately. It is shown that dynamics of the overall fingers and object system satisfy passivity but residual error dynamics for a given periodic posture of the object and a fixed value of contact force satisfy output‐dissipativity only in an approximate sense. Numerical simulation results are presented which show that the pair of fingers manipulating an object is capable of learning iteratively a variety of dexterous motions with a good performance. 相似文献
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This article analyzes the dynamics of motion of various setups of two multiple degree‐of‐freedom (DOF) fingers that have soft tips, in fine manipulation of an object, and shows performances of their motions via computer simulation. A mathematical model of these dynamics is described as a system of nonlinear differential equations expressing motion of the overall fingers‐object system together with algebraic constraints due to tight area contacts between the finger‐tips and surfaces of the object. First, problems of (1) dynamic, stable grasping and (2) regulation of the object rotational angle by means of a setup of dual two‐DOF fingers, are treated. Second, the problem of regulating the position of the object mass center by means of a pair of two‐DOF and three‐DOF fingers is considered. Third, a set of dual three‐DOF fingers is treated, in order to let it perform a sophisticated task, which is specified by a periodic pattern of the object posture and a constant internal force. In any case, there exist sensory‐motor coordinations, which are described by analytic feedback connections from sensing to actions at finger joints. In the cases of setpoint control problems, convergences of motion to secure grasping together with the specified object rotational angle and/or the specified object mass center position, are proved theoretically. A constraint stabilization method (CSM) is used for solving numerically the differential algebraic equations to show performances of the proposed sensory‐feedback schemes. © 2002 Wiley Periodicals, Inc. 相似文献
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This paper proposes dynamic capturing strategies where a 2D stick-shaped object with both translational and rotational velocity is completely stopped by two robotic fingers. We first show the fingertip position and the object orientation for generating a desired velocity of the object under the friction independent collision. Once the object results in a pure translational motion whose direction is perpendicular to the longitudinal axis of object, it is guaranteed that two fingers can always capture the object irrespective of friction coefficient. By using this nature, we show both 2-step and 3-step capturing strategies for a 2D stick-shaped object whose width is negligibly small. The 3-step capturing strategy can guide the object in an arbitrary direction, while the 2-step one can do it only in a particular direction. The proposed strategies are demonstrated by experiments for verifying our idea. 相似文献
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《Annual Reviews in Control》2004,28(1):75-85
This paper is concerned with intelligent control for grasping and manipulation of an object by multi-fingered robot hands with rigid or soft hemispheric finger ends that induce rolling contacts with the object. Even in the case of 2D motion like pinching by means of a pair of multi-degrees of freedom robot fingers, there arises an interesting family of Lagrange’s equations of motion with many geometric constraints, which are under-actuated, redundant, and non-holonomic in some sense. Regardless of underactuation of dynamics, it is possible to find a class of sensory feedback signals that realize secure grasp of an object together with control of object orientation. In regard to the secure grasping, a problem of force/torque closure for 2D objects in a dynamic sense plays a crucial role. It is shown that proposed sensory feedback signals satisfying the dynamic force/torque closure can be constructed without knowing object kinematic parameters and location of the mass center. To prove the convergence of motion of the overall fingers–object system under the circumstance of redundancy of joints, new concepts called “stability on a manifold” and “asymptotic stability on a manifold” are introduced. Based on the results found for intelligent control of robotic hands, the last two sections attempt to discuss why human multi-fingered hands can become so dexterous at grasping and object manipulation. 相似文献
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V. Parra-Vega A. Rodríguez-Angeles S. Arimoto G. Hirzinger 《Journal of Intelligent and Robotic Systems》2001,32(3):235-254
A method for high precision constrained object manoeuvering for non-redundant rigid multifinger hands is proposed. A passivity-based adaptive cooperative control scheme carries out compensation of all uncertain inertial and dynamic friction forces to guarantee asymptotic tracking of all contact forces and joint position-orientation trajectories over orthogonal force- and position-based impedance error manifolds. Optimal internal and external force trajectories are obtained to minimize the contact forces onto the constrained object while exerting a given desired contact force onto the environment. The simulation study of two robot fingers manipulating a constrained object for combined fast and slow velocity regimes shows that when the dynamic friction compensation is turned on tracking errors decrease tenfold. 相似文献
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A mathematical model expressing the motion of a pair of multi-DOF robot fingers with hemi-spherical ends, grasping a 3-D rigid object with parallel flat surfaces, is derived, together with non-holonomic constraints. By referring to the fact that humans grasp an object in the form of precision prehension, dynamically and stably by opposable forces, between the thumb and another finger (index or middle finger), a simple control signal constructed from finger-thumb opposition is proposed, and shown to realize stable grasping in a dynamic sense without using object information or external sensing (this is called "blind grasp" in this paper). The stability of grasping with force/torque balance under non-holonomic constraints is analyzed on the basis of a new concept named "stability on a manifold". Preliminary simulation results are shown to verify the validity of the theoretical results. 相似文献
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Qualitative detection of motion by a moving observer 总被引:2,自引:2,他引:0
Randal C. Nelson 《International Journal of Computer Vision》1991,7(1):33-46
Two complementary methods for the detection of moving objects by a moving observer are described. The first is based on the fact that, in a rigid environment, the projected velocity at any point in the image is constrained to lie on a 1-D locus in velocity space whose parameters depend only on the observer motion. If the observer motion is known, an independently moving object can, in principle, be detected because its projected velocity is unlikely to fall on this locus. We show how this principle can be adapted to use partial information about the motion field and observer motion that can be rapidly computed from real image sequences. The second method utilizes the fact that the apparent motion of a fixed point due to smooth observer motion changes slowly, while the apparent motion of many moving objects such as animals or maneuvering vehicles may change rapidly. The motion field at a given time can thus be used to place constraints on the future motion field which, if violated, indicate the presence of an autonomously maneuvering object. In both cases, the qualitative nature of the constraints allows the methods to be used with the inexact motion information typically available from real-image sequences. Implementations of the methods that run in real time on a parallel pipelined image processing system are described. 相似文献