By Topic

Robotics and Automation, IEEE Transactions on

Issue 1 • Date Feb 1992

Filter Results

Displaying Results 1 - 16 of 16
  • A contact stress model for multifingered grasps of rough objects

    Publication Year: 1992 , Page(s): 7 - 22
    Cited by:  Papers (29)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1252 KB)  

    A model that utilizes a contact-stress analysis of an arbitrarily shaped object in a multifingered grasp is developed. The fingers and the object are all treated as elastic bodies, and the region of contact is modeled as a deformable surface patch. The relationship between the friction and normal forces is now nonlocal and nonlinear in nature and departs from the Coulomb approximation. The nature of the constraints arising out of conditions for compatibility and static equilibrium motivated the formulation of the model as a nonlinear constrained minimization problem. The model is able to predict the magnitude of the inwardly directed normal forces and both the magnitude and direction of the tangential (friction) forces at each finger/object interface for grasped objects in static equilibrium. Examples in two and three dimensions are presented along with an application of the model to the grasp transfer maneuver View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A potential field approach to path planning

    Publication Year: 1992 , Page(s): 23 - 32
    Cited by:  Papers (136)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1172 KB)  

    A path-planning algorithm for the classical mover's problem in three dimensions using a potential field representation of obstacles is presented. A potential function similar to the electrostatic potential is assigned to each obstacle, and the topological structure of the free space is derived in the form of minimum potential valleys. Path planning is done at two levels. First, a global planner selects a robot's path from the minimum potential valleys and its orientations along the path that minimize a heuristic estimate of the path length and the chance of collision. Then, a local planner modifies the path and orientations to derive the final collision-free path and orientations. If the local planner fails, a new path and orientations are selected by the global planner and subsequently examined by the local planner. This process is continued until a solution is found or there are no paths left to be examined. The algorithm solves a much wider class of problems than other heuristic algorithms and at the same time runs much faster than exact algorithms (typically 5 to 30 min on a Sun 3/260) View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modeling a class of multilink manipulators with the last link flexible

    Publication Year: 1992 , Page(s): 33 - 41
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB)  

    Dynamic equations are derived for a class of multilink manipulators with the last link flexible. The manipulators have three degrees of freedom and are moved by three actuators. This class includes the elbow manipulator and the five-bar-linkage manipulator. Some reasonable assumptions that simplify the dynamic equations for control purposes are described, and the simplified dynamic equations are then presented. It is shown that, for pick-and-place operations, a rigid-body robot controller and a single flexible link controller may be combined to control the manipulator in a straightforward manner View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dynamic control of sliding by robot hands for regrasping

    Publication Year: 1992 , Page(s): 42 - 52
    Cited by:  Papers (53)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1020 KB)  

    The problem of dynamic control of a multifingered hand manipulating an object is considered, under the condition that some of the fingertips slide on the object surface. This work has many useful applications when considered in conjunction with work already done in the area of regrasping. In performing certain tasks with grasped objects, it is often necessary to change the contact locations of the fingers on the object. One method of achieving this is to break and remake the contacts; another method is to slide the fingertips on the object surface. This work provides a dynamic coordinated control scheme for a hand by which one can perform regrasping and reorientation of an object in the planar case View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An electrooptical orientation sensor for robotics

    Publication Year: 1992 , Page(s): 111 - 119
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (724 KB)  

    The design and analysis of a noncontact electrooptical orientation sensor is addressed. The sensor is based on the intensity measurement of modulated light signals reflected from the surface of an object. The experimental setup of the sensor used in this research was designed and manufactured such that two mechanical-design parameters could be investigated. The operation principle of the 1D inclination-angle measurement sensor was verified using the experimental setup as well as through simulation. Experiments undertaken yielded an optimal sensor design that can effectively operate within a range from +20° to -20° independent of its distance from the object (within the operational-distance range of the sensor) View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dynamic hybrid velocity/force control of robot compliant motion over globally unknown objects

    Publication Year: 1992 , Page(s): 132 - 138
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (628 KB)  

    The application of robotic manipulators to complex tasks such as assembly, or insertion often requires position/force control of the end-effector, and this has been widely studied. A related task is robot compliant motion over unknown objects. The goal is to move the effector, while maintaining contact, about the object. For this application a dynamic hybrid velocity/force controller is studied. The constraints are characterized in the manner proposed by M. Mason (1981). A nominal velocity trajectory is computed, and nominal hybrid joint commands are explicitly given in terms of the sensed joint coordinates and sensed local contact information. For robustness, servoing is added, and an example design is given. Finally, the step response of the controller is simulated for the case of rolling the effector about an unknown object View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Locally efficient path planning in an uncertain, dynamic environment using a probabilistic model

    Publication Year: 1992 , Page(s): 105 - 110
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB)  

    The problem addressed is that of efficiently planning a path for a robot between two points when the path is forced to change dynamically by the occurrence of certain events in the environment. An event or an alarm, for example, may be the discovery of another moving object on a collision course with the robot and would require some evasive action. A probabilistic model is given that represents the robot's dynamic behavior in response to alarms that have a Poisson distribution, and safety rules that assume that some regions are safe. A provably optimal expected solution for the problem is given, and the variation of the optimal path with two parameters that represent the alarm rate and the safety rule, respectively, is discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Quaternion kinematic and dynamic differential equations

    Publication Year: 1992 , Page(s): 53 - 64
    Cited by:  Papers (60)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (844 KB)  

    Many useful identities pertaining to quaternion multiplications are generalized. Among them multiplicative commutativity is the most powerful. Since quaternion space includes the 3D vector space, the physical quantities related to rotations, such as angular displacement, velocity, acceleration, and momentum, are shown to be vector quaternions, and their expressions in quaternion space are derived. These kinematic and dynamic differential equations are further shown to be invertible due to the fact that they are written in quaternion space, and the highest order term of the rotation parameters can be expressed explicitly in closed form View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A tactile sensor based on a suspension-shell mechanism for dexterous fingers

    Publication Year: 1992 , Page(s): 126 - 131
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB)  

    The design and experimental results for a suspension-shell tactile sensor are described. The sensor uses a suspension-shell mechanism to make the entire surroundings of a finger-body sensitive. The sensor detects the magnitude and the point of application of an external force operating on the shell by measuring the relative displacement of the suspension shell with regard to the finger-body. However, the force distribution is not provided since the sensor has no arrays, and the sensor records the actual force distributed over the surface area of the sensor shell as an integrated force at a single point of action. Sensing at the fingertip is excluded since the prototype sensor is designed for detecting lateral force rather than coaxial force for the first step. The sensor's basic characteristics and how it works in practice are shown View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Coordinated motion control of robot arms based on the virtual internal model

    Publication Year: 1992 , Page(s): 77 - 85
    Cited by:  Papers (35)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1380 KB)  

    An alternative coordinated motion control architecture for robot arms manipulating an object is proposed. The motion and the internal force of the object are resolved in the motion of each arm. Each arm's control is based on the virtual internal model so as to operate in coordination even if geometric errors exist in the robot arms and the object. The virtual internal model is a reference model driven by sensory information implemented in the controller. The proposed architecture keeps the state of the system bounded even if breakage of the manipulated object occurs. The control algorithm is experimentally applied to the coordinated motion control of two planar robot arms, each of which has three degrees of freedom. The results illustrate the validity of the proposed control architecture View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Trajectory tracking in robot manipulators via nonlinear estimated state feedback

    Publication Year: 1992 , Page(s): 138 - 144
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    High-precision measurements of joint displacements are available on robot manipulators. In contrast, velocity measurements obtained through tachometers are, in many cases, contaminated by noise. It is therefore economically and technically interesting to investigate the possibility of controlling robot dynamics by only using angular position measurements. Two alternative approaches for trajectory tracking control via nonlinear estimated state feedback are presented. The first scheme is based on smooth functions, whereas the second uses switching gains. The stability of the closed-loop system is investigated. Both approaches yield exponentially stable closed-loop systems. The local attraction areas are characterized in terms of controller and observer gains, initial state values, and robot model parameters View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Computer-automated symbolic modeling of dynamics of robotic manipulators with flexible links

    Publication Year: 1992 , Page(s): 94 - 105
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (576 KB)  

    Dynamic equations are developed in nonrecursive symbolic form for chain-structured robotic manipulators with compliant links. A program is developed in REDUCE to automate the symbolic expansion of these equations for any given chain-structured manipulator. The symbolic nonrecursive form of the dynamic model is particularly suitable for controller synthesis and real-time control implementations View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Stability and control of elastic-joint robotic manipulators during constrained-motion tasks

    Publication Year: 1992 , Page(s): 119 - 126
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    The effect of a major source of manipulator compliance, namely, the elasticity of manipulator joints, on the overall stability of robot manipulators during constrained-motion task execution is examined. The stability of the elastic-joint manipulator during constrained-motion contact is investigated separately for the case of two controls applied to the manipulator. Using results from the theory of singular perturbations, the stability of the robotic system is established with a `rigid' control law applied. The stability of the robotic system is again established using this technique for the case of a `rigid' control law with a corrective term applied to compensate for joint flexibility applied. It is theoretically established that the presence of joint elasticity does not lead to a destabilizing effect on the manipulator. Numerical simulation results for a two-degree-of-freedom flexible-joint manipulator during constrained-motion task execution confirm the theoretical results View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis of a redundant free-flying spacecraft/manipulator system

    Publication Year: 1992 , Page(s): 1 - 6
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    An analysis of the momentum conservation equations of a redundant free-flying spacecraft/manipulator system acting in a zero-gravity environment is presented. In order to follow a predefined end-effector path, the inverse kinematics at velocity level is considered. The redundancy is solved alternatively in terms of pseudoinverses and null-space components of the manipulator inertia matrix, the manipulator Jacobian matrix, and the generalized Jacobian matrix. A general manipulation task is defined as end-effector continuous path tracking with simultaneous attitude control of the spacecraft. Three subtasks of the general task are considered. The case of manipulator motions that yield no spacecraft attitude disturbance is analyzed in more detail and a special `fixed-attitude-restricted' (FAR) Jacobian is defined. Through singular-value decomposition of this Jacobian, corresponding FAR dexterity measures (FAR manipulability and FAR condition number) are derived View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Spatial operator factorization and inversion of the manipulator mass matrix

    Publication Year: 1992 , Page(s): 65 - 76
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB)  

    This paper advances two linear operator factorizations of the manipulator mass matrix. Embedded in the factorizations are many of the techniques that are regarded as very efficient computational solutions to inverse and forward dynamics problems. The operator factorizations provide a high-level architectural understanding of the mass matrix and its inverse, which is not visible in the detailed algorithms. They also lead to an approach to the development of computer programs or the organisation of complexity in robot dynamics View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Control of the welding process using infrared sensors

    Publication Year: 1992 , Page(s): 86 - 93
    Cited by:  Papers (8)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (748 KB)  

    Integration of sensors in a welding system enhances the quality of the welds produced. Variations in three welding process parameters-weld bead width, penetration depth, and torch position-were monitored using an infrared sensor. Intentionally induced variations in each of these welding parameters were found to affect uniquely the plate surface temperature distributions measured by the infrared sensor. The effects of weld bead width and torch position perturbations on the temperature distribution were separated so as to identify and control these two weld process parameters simultaneously. Preliminary results suggest that simultaneous penetration depth, bead width, and torch position control is possible View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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