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Robotics and Automation, IEEE Journal of

Issue 3 • Date Jun 1988

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Displaying Results 1 - 13 of 13
  • Direct-drive active compliant end effector (active RCC)

    Publication Year: 1988 , Page(s): 324 - 333
    Cited by:  Papers (18)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (808 KB)  

    A fast, lightweight, active end-effector, which can be attached to the endpoint of a commercial robot manipulator, has been designed and built using an impedance-control method. This control method causes the end-effector to behave dynamically as a two-dimensional remote center compliance (RCC). The compliancy is in this active end-effector is electronic and can be modulated by an online computer. The device is planar and five-bar linkage, and is driven by two direct-drive, brushless DC motors. A two-dimensional, piezoelectric force cell on the endpoint of the device, two 12-bit encoders, and two tachometers on the motors form the measurement system. The high structural stiffness and light weight of the material used in the system allow for a 15-Hz-bandwidth impedance control View full abstract»

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  • Stabilization of uncertain systems subject to hard bounds on control with application to a robot manipulator

    Publication Year: 1988 , Page(s): 310 - 323
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (644 KB)  

    The problem of estimating the region of stability for uncertain systems with bounded controllers and the sliding mode requirement is examined. A novel type of controller for a class of linear time-invariant systems subject to uncertainties is proposed. A transformation for decoupling the fast and slow states is utilized to investigate the stability-domain estimates of the system. The results are then applied to a two-joint planar manipulator and illustrated by computer simulation View full abstract»

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  • A variational dynamic programming approach to robot-path planning with a distance-safety criterion

    Publication Year: 1988 , Page(s): 334 - 349
    Cited by:  Papers (22)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1244 KB)  

    An approach to robot-path planning is developed by considering both the traveling distance and the safety of the robot. A computationally-efficient algorithm is developed to find a near-optimal path with a weighted distance-safety criterion by using a variational calculus and dynamic programming (VCDP) method. The algorithm is readily applicable to any factory environment by representing the free workspace as channels. A method for deriving these channels is also proposed. Although it is developed mainly for two-dimensional problems, this method can be easily extended to a class of three-dimensional problems. Numerical examples are presented to demonstrate the utility and power of this method View full abstract»

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  • Pilot level of a hierarchical controller for an unmanned mobile robot

    Publication Year: 1988 , Page(s): 241 - 255
    Cited by:  Papers (25)  |  Patents (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1144 KB)  

    The controller for an intelligent mobile autonomous system (IMAS), equipped with vision and low-level sensors to cope with unknown obstacles, is modeled as a hierarchy of decision-making for planning and control. One of the levels (pilot) deals with a distorted `windshield' view of the world and provides the actuator controller with real-time decisions. This level of IMAS controller is treated as a linguistic controller with fuzzy variables that assume values from possible intervals. The decision-making process at this level of control are presented as a production system with a fuzzy database. The rules in the production system are derived from an analytical system model for minimum-time control. The choice of optimal motion execution commands is performed using fuzzy set operators. Also included is a temporal decision-making mechanism (reporter), which recognizes the persisting conflicts between successive levels of the hierarchy by observing the motion trajectory View full abstract»

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  • Vehicle path specification by a sequence of straight lines

    Publication Year: 1988 , Page(s): 265 - 276
    Cited by:  Papers (48)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (832 KB)  

    A path-description method that uses a sequence of straight lines with coordinate transformations is presented. This concept is hardware-independent and may be applied to any kind of vehicle. A local vehicle-trajectory-control algorithm is used both for determining the transient portions of each vehicle trajectory and for keeping the vehicle moving along a given directed straight line. A vehicle-control command-system, MITCHI, is one realization of the idea and is introduced. The MITCHI command-system has been implemented on self-contained Yamabico mobile robots. Several design features, such as status transition, fast/slow command execution, and velocity control, as well as simulation results, are described View full abstract»

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  • A control algorithm for hexapod walking machine over soft ground

    Publication Year: 1988 , Page(s): 294 - 302
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (748 KB)  

    A control algorithm is presented for a hexapod walking machine, with alternating tripod-gait, proceeding over soft ground. The control algorithm is based on a foot-force sensing and is composed of two parts. The first part, which is applied to the leg alternating phase, confirms the support of body weight and generates the ground model using internal sensors. The second, which is applied to the body-propelling phase, compensates for the additional ground-sinkage due to the change of supporting force using the generated ground model. The proposed control algorithm is incorporated into the hexapod walking machine (MELWALK-III) and some basic experiments are performed to demonstrate the effectiveness of the algorithm for three types of ground simulations View full abstract»

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  • Concurrent routing, sequencing, and setups for a two-machine flexible manufacturing cell

    Publication Year: 1988 , Page(s): 256 - 264
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (796 KB)  

    An approach that allows in-process machine-loading through magazine setups, and concurrently routes and sequences the jobs on the versatile machines, is presented. To illustrate the concurrent approach, a specific two-versatile-machine flowshop scheduling problem, referred to as 2-VFSP, is defined and studied in detail. Theoretical results show that the optimal schedule for 2-VFSP need not have more than two in-process magazine setups, giving rise to the three possible scheduling configurations. Further, it is proven that obtaining the optimal schedule is an NP-complete problem. A heuristic is developed and tested on sets of random joblists, with different setup times corresponding to varying degrees of machine versatility. Results indicate that schedules which incorporate in-process magazine setup(s) may be more desirable when the setup time is small. Thus the use of concurrent scheduling approach which allows in-process magazine setups may be especially useful for systems with very versatile machines View full abstract»

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  • Robot control in the neighborhood of singular points

    Publication Year: 1988 , Page(s): 303 - 309
    Cited by:  Papers (13)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    An alternative method is proposed for designing a robot-controller in Cartesian coordinates using a time-scale transformation. The proposed controller achieves slow poles in the area of poor manipulative ability and fast poles in the area of good manipulative ability. Therefore, the robot can be properly controlled in the neighbourhood of singular points without reducing the performance outside the neighborhood of these points View full abstract»

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  • Dynamic analysis of a three-degrees-of-freedom in-parallel actuated manipulator

    Publication Year: 1988 , Page(s): 361 - 367
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    The dynamic analysis of a three-degrees-of-freedom in-parallel actuated manipulator is presented. The equations of motion have been formulated in joint-space using the Lagrangian approach. The analysis provides the solution to predict the forces required to actuate the links so that the manipulator follows a predetermined trajectory. A dynamic simulation program illustrates the influence of the link dynamics on the actuating force required. An example of tracing a helical path is chosen to illustrate the dynamic simulation and to show that the Cartesian position of the moving platform may be controlled at a sacrifice of orientation freedoms. The dynamic analysis provides a basis for future theoretical research to develop the control scheme, for experimental research to estimate the inertia parameters, and for design optimization of the prototype manipulator View full abstract»

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  • Automatic generation and synthesis of C-frames for mechanical parts in an insertion task

    Publication Year: 1988 , Page(s): 287 - 293
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    An approach that utilizes the geometric information about the mating parts in generating and synthesizing the C-frame and the compliance-selection vector which are needed at every sampling instant for hybrid position/force control scheme in an insertion task, is presented. A geometric modeling system is used to model the mating objects involved in the insertion task. From the geometric model of the objects and the nominal position-trajectory of the task, a set of cut-planes of the mating objects perpendicular to the insertion direction can be obtained. Due to the uncertainties inherent in working with real-world objects, and the limited position accuracy of the manipulator, an uncertainty model is incorporated into the cut-planes to reflect the position and orientation uncertainties of the C-frame. This approach reduces a difficult three-dimensional problem into a set of two-dimensional problems and will successfully complete the task even in the presence of position and orientation uncertainties View full abstract»

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  • A maximum-likelihood approach to segmenting range data

    Publication Year: 1988 , Page(s): 277 - 286
    Cited by:  Papers (16)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1284 KB)  

    The problem of segmenting a range image into homogeneous regions in each of which the range data correspond to a different surface is considered. The segmentation sought is a maximum-likelihood (ML) segmentation. Only planes, cylinders, and spheres are considered as presented in the image. The basic approach to segmentation is to divide the range image into windows, classify each window as a particular surface primitive, and group like windows into surface regions. Mixed windows are detected by testing the hypothesis that a window is homogeneous. Homogeneous windows are classified according to a generalized likelihood ratio test which is computationally simple and incorporates information from adjacent windows. Grouping windows of the same surface types is cast as a weighted ML clustering problem. Finally, mixed windows are segmented using an ML hierarchical segmentation algorithm. A similar approach is taken for segmenting visible-light images of Lambertian objects illuminated by a point source at infinity View full abstract»

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  • Kinematic analysis of a three-degrees-of-freedom in-parallel actuated manipulator

    Publication Year: 1988 , Page(s): 354 - 360
    Cited by:  Papers (93)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    An alternative design of a three-degrees-of-freedom manipulator based on the concept of an in-parallel actuated mechanism is presented. The manipulator has two degrees of orientation freedom and one degree of translatory freedom. The basic kinematic equations for use of the manipulator are derived and the influences of the physical constraints on the range of motion in the practical design are discussed. Several possible applications which include the in-parallel mechanism as part of the manipulation system are suggested View full abstract»

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  • Subtask performance by redundancy resolution for redundant robot manipulators

    Publication Year: 1988 , Page(s): 350 - 354
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    The problem of selecting joint space trajectories for redundant manipulators is considered. Solutions which allow secondary tasks to be performed by the arm simultaneously with end-effector motions may be selected in a number of ways. An algorithm to accomplish this, by means of conditions on a scalar function of the joint variables, is introduced and analyzed. Problems inherent in schemes involving constraints in configuration space are considered View full abstract»

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Aims & Scope

This Journal ceased production in 1988. The current retitled publications are IEEE Transactions on Automation Science and Engineering and IEEE Transactions on Robotics.

Full Aims & Scope