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Robotics and Automation, IEEE Transactions on

Issue 3 • Date Jun 2001

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Displaying Results 1 - 13 of 13
  • Positioning of toleranced parts in a 2D polygonal assembly and its use in tolerance analysis

    Publication Year: 2001 , Page(s): 357 - 360
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    The paper analyzes the mating natures of a 2D polygonal assembly and discusses uncertainty in assemblies due to the geometric (size and shape) variations of the assembled parts. To study variant assembly configurations, translational and rotational motion constraints are generated by analyzing geometric contact relations between variant parts. Based on these motion constraints, the uncertainty build-ups in an assembly of toleranced parts are investigated View full abstract»

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  • Optimizing fixture layout in a point-set domain

    Publication Year: 2001 , Page(s): 312 - 323
    Cited by:  Papers (51)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB) |  | HTML iconHTML  

    This paper describes an approach to optimal design of a fixture layout with the minimum required number of elements, i.e., six locators and a clamp. The approach applies to parts with arbitrary 3D geometry and is restricted to be within a discrete domain of locations for placing the fixture elements of non-frictional contacts. The paper addresses two major issues: 1) to develop an efficient algorithm for fixture synthesis in the point set domain; and 2) to evaluate the acceptable fixture designs based on several performance criteria and to select the optimal fixture according to practical requirements. The performance objectives considered include the workpiece localization accuracy, and the norm and dispersion of the locator contact forces. An interchange algorithm with random initiation is developed. Also, the fixture performance characteristics are evaluated to understand their tradeoffs. The importance of the accurate localization and the contact force balance is discussed View full abstract»

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  • Analytical time optimal control solution for a two-link planar aerobot with initial angular momentum

    Publication Year: 2001 , Page(s): 361 - 366
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (204 KB) |  | HTML iconHTML  

    In order to control gymnastic and jumping robots, we derive the complete analytical solution to the posture control problem of a two-link free flying object with initial angular momentum. We show that the solution involves singular control and derive formulas to calculate the optimal switching condition, optimal terminal time and optimal trajectories. As an application, a high diving motion is simulated View full abstract»

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  • Automatic data segmentation for geometric feature extraction from unorganized 3-D coordinate points

    Publication Year: 2001 , Page(s): 268 - 279
    Cited by:  Papers (31)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB) |  | HTML iconHTML  

    A systematic approach is proposed to automatically extract geometric surface features from a point cloud composed of a set of unorganized three-dimensional coordinate points by data segmentation. The point cloud is sampled from the boundary surface of a mechanical component with arbitrary shape. The proposed approach is composed of three steps. In the first step, a mesh surface domain is reconstructed to establish an explicit topological relation among the discrete points. The topological adjacency is further optimized to recover the second order object geometry. In the second step, curvature-based border detection is applied on the irregular mesh to extract both sharp borders with tangent discontinuity and smooth borders with curvature discontinuity. Finally, the mesh patches separated by the extracted borders are grouped together in the third step. For objects with complex shape, a multilevel segmentation scheme is proposed for better results. The capability of the proposed approach is demonstrated using various point clouds having distinct characteristics. Integrated with state of art scanning devices, the developed segmentation scheme can support reverse engineering of high precision mechanical components. It has potential applications in a whole spectrum of engineering problems with a major impact on rapid design and prototyping, shape analysis, and virtual reality View full abstract»

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  • Double active universal joint (DAUJ): robotic joint mechanism for human-like motions

    Publication Year: 2001 , Page(s): 290 - 300
    Cited by:  Papers (10)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    We present a robotic joint mechanism that makes it possible to mimic the human-like motions. The proposed robotic joint, called the double active universal joint (DAUJ), generates a two-degree of freedom motion suppressing rolling by the coupled motions of two independent motors. The mechanism design and kinematics are mentioned. Two application examples are outlined: an anthropomorphic finger and an in-pipe inspection robot. The results of basic experiments are reported to confirm the effectiveness of the proposed mechanism. Also, we briefly introduce the advantage that the compliance of the proposed mechanism can be easily controlled by modulating the engagement period of the magnetic clutch View full abstract»

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  • Computing the sensory uncertainty field of a vision-based localization sensor

    Publication Year: 2001 , Page(s): 258 - 267
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (228 KB) |  | HTML iconHTML  

    It has been recognized that robust motion planners should take into account the varying performance of localization sensors across the configuration space. Although a number of works have shown the benefits of using such a performance map, the work on actual computation of such a performance map has been limited and has addressed mostly range sensors. Since vision is an important sensor for localization, it is important to have performance maps of vision sensors. We present a method for computing the performance map of a vision-based sensor. We compute the map and show that it accurately describes the actual performance of the sensor, both on synthetic and real images. The method we use involves evaluating closed form formulas and hence is very fast. Using the performance map computed by this method for motion planning and for devising sensing strategies will contribute to more robust navigation algorithms View full abstract»

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  • Planning walking patterns for a biped robot

    Publication Year: 2001 , Page(s): 280 - 289
    Cited by:  Papers (259)  |  Patents (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB) |  | HTML iconHTML  

    Biped robots have better mobility than conventional wheeled robots, but they tend to tip over easily. To be able to walk stably in various environments, such as on rough terrain, up and down slopes, or in regions containing obstacles, it is necessary for the robot to adapt to the ground conditions with a foot motion, and maintain its stability with a torso motion. When the ground conditions and stability constraint are satisfied, it is desirable to select a walking pattern that requires small torque and velocity of the joint actuators. We first formulate the constraints of the foot motion parameters. By varying the values of the constraint parameters, we can produce different types of foot motion to adapt to ground conditions. We then propose a method for formulating the problem of the smooth hip motion with the largest stability margin using only two parameters, and derive the hip trajectory by iterative computation. Finally, the correlation between the actuator specifications and the walking patterns is described through simulation studies, and the effectiveness of the proposed methods is confirmed by simulation examples and experimental results View full abstract»

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  • Singularity analysis of a class of composite serial in-parallel robots

    Publication Year: 2001 , Page(s): 301 - 311
    Cited by:  Papers (14)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB) |  | HTML iconHTML  

    This paper presents the singularity analysis of a family of 14 composite serial in-parallel six degree-of-freedom robots, having a common parallel sub-mechanism. The singular configurations of this class of robots are obtained by applying line geometry methods to a single, augmented Jacobian matrix whose rows are Plucker coordinates of the lines governing the sub-mechanism motion. It is shown that this family of robots possesses three general parallel singularities that are attributed to the general complex singularity. The results were verified experimentally on a prototype of a composite serial in-parallel robot that was synthesized and constructed for use in medical applications View full abstract»

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  • Scheduling in dual gripper robotic cells for productivity gains

    Publication Year: 2001 , Page(s): 324 - 341
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (508 KB) |  | HTML iconHTML  

    We consider single part-type problems. Since all parts produced are identical, it is sufficient to determine the sequence of moves performed by the robot. The processing constraints define the cell to be a flowshop. The objective is the minimization of the steady-state cycle time to produce a part, or equivalently the maximization of the throughput rate. We study the problem of scheduling robot moves in dual gripper robot cells functioning in a bufferless environment. We develop an analytical framework for studying dual gripper robotic cells and examine the cycle time advantage of using a dual gripper rather than a single gripper robot. It is shown that an m-machine dual gripper robot cell can have at most double the productivity of its single gripper counterpart. We also propose a practical heuristic algorithm to compare productivity for given cell data. Computational testing of the algorithm on realistic problem instances is also described View full abstract»

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  • Optimization of the simultaneous localization and map-building algorithm for real-time implementation

    Publication Year: 2001 , Page(s): 242 - 257
    Cited by:  Papers (215)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB) |  | HTML iconHTML  

    Addresses real-time implementation of the simultaneous localization and map-building (SLAM) algorithm. It presents optimal algorithms that consider the special form of the matrices and a new compressed filler that can significantly reduce the computation requirements when working in local areas or with high frequency external sensors. It is shown that by extending the standard Kalman filter models the information gained in a local area can be maintained with a cost ~O(Na2), where Na is the number of landmarks in the local area, and then transferred to the overall map in only one iteration at full SLAM computational cost. Additional simplifications are also presented that are very close to optimal when an appropriate map representation is used. Finally the algorithms are validated with experimental results obtained with a standard vehicle running in a completely unstructured outdoor environment View full abstract»

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  • A solution to the simultaneous localization and map building (SLAM) problem

    Publication Year: 2001 , Page(s): 229 - 241
    Cited by:  Papers (620)  |  Patents (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    The simultaneous localization and map building (SLAM) problem asks if it is possible for an autonomous vehicle to start in an unknown location in an unknown environment and then to incrementally build a map of this environment while simultaneously using this map to compute absolute vehicle location. Starting from estimation-theoretic foundations of this problem, the paper proves that a solution to the SLAM problem is indeed possible. The underlying structure of the SLAM problem is first elucidated. A proof that the estimated map converges monotonically to a relative map with zero uncertainty is then developed. It is then shown that the absolute accuracy of the map and the vehicle location reach a lower bound defined only by the initial vehicle uncertainty. Together, these results show that it is possible for an autonomous vehicle to start in an unknown location in an unknown environment and, using relative observations only, incrementally build a perfect map of the world and to compute simultaneously a bounded estimate of vehicle location. The paper also describes a substantial implementation of the SLAM algorithm on a vehicle operating in an outdoor environment using millimeter-wave radar to provide relative map observations. This implementation is used to demonstrate how some key issues such as map management and data association can be handled in a practical environment. The results obtained are cross-compared with absolute locations of the map landmarks obtained by surveying. In conclusion, the paper discusses a number of key issues raised by the solution to the SLAM problem including suboptimal map-building algorithms and map management View full abstract»

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  • Deadlock detection, prevention, and avoidance for automated tool sharing systems

    Publication Year: 2001 , Page(s): 342 - 356
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB) |  | HTML iconHTML  

    Automated tool sharing systems provide a technological response to the high cost of tools in flexible manufacturing systems. These systems allow different machines to use the same tools by automatically transferring them from machine to machine as tooling needs evolve. With these systems, tool allocation is a real-time issue that requires sophisticated control techniques to make the right allocation decisions. An essential property that tool sharing policies must guarantee is deadlock-free operation. Although manufacturing researchers have investigated the performance aspects of tool sharing through simulation, no work has yet addressed deadlock handling strategies for these real-time systems. In this paper, we characterize the structural and computational properties of the tooling deadlock problem. We develop polynomial algorithms that detect and avoid deadlock, and we investigate the safety implications of special structures appearing in tool sequences View full abstract»

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  • Design of steering mechanism and control of nonholonomic trailer systems

    Publication Year: 2001 , Page(s): 367 - 374
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (292 KB) |  | HTML iconHTML  

    A wheeled mobile robot with trailers has been studied as a class of nonholonomic systems. It is proved that a system of a tractor and trailers with an appropriate connecting mechanism can be stabilized to desired positions via nonholonomic motion control. Trailers, on the other hand, have been developed and widely used in the industry. The main focus of industrial design is set on reducing tracking error from a reference trajectory. This paper attempts to bridge over the gap between these two approaches. We develop a design theory of trailer systems with passive steering. The designed systems show a good performance in practical path following, and accept the chained form transformation and nonlinear control strategies for nonholonomic systems View full abstract»

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Aims & Scope

This Transactions ceased production in 2004. The current retitled publications areIEEE Transactions on Automation Science and Engineering and IEEE Transactions on Robotics.

Full Aims & Scope