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Articles 1201 - 1220 of 1220

Full-Text Articles in Robotics

Derivation Of Equations Of Motion For A Four Link Robotic Leg For A Walking Vehicle, Andrew B. Wright Jan 1999

Derivation Of Equations Of Motion For A Four Link Robotic Leg For A Walking Vehicle, Andrew B. Wright

Journal of the Arkansas Academy of Science

A four degree of freedom leg for a walking robot has been modeled using Newton's method. Unlike robot manipulators, which have a fixed base, a leg model must include inertial forces due to base motion. These forces have been included in the formulation. These equations can be used for design, simulation, and control. The inverse kinematics for this leg are also presented. This allows the joint angles to be computed from a desired foot-hold position.

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Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz Nov 1998

Robust Course-Boundary Extraction Algorithms For Autonomous Vehicles, Chris Roman, Charles Reinholtz

Graduate School of Oceanography Faculty Publications

Practical autonomous robotic vehicles require dependable methods for accurately identifying course or roadway boundaries. The authors have developed a method to reliably extract the boundary line using simple dynamic thresholding, noise filtering, and blob removal. This article describes their efforts to apply this procedure in developing an autonomous vehicle.

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Self-Assembly Of Microstructures, Paul E. Kladitis Dec 1997

Self-Assembly Of Microstructures, Paul E. Kladitis

Theses and Dissertations

Four areas are investigated in this research: erecting microstructures normal to the substrate plane without direct human intervention (self-assembled), providing low resistance electrical connections to the erected microstructure, realizing circular motion normal to the substrate plane, and implementing a micro-robot. The designs in this research concentrate on erecting and providing power to a leg designed for use with the micro-robot. The leg and the attached low resistance electrical connectors were not self-assembled because the accompanying actuators were not powerful enough. However, the novel connectors provide the most practical, versatile, and lowest possible resistance connections for the MUMPs fabrication process. The …

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Globally Optimal Periodic Robot Joint Trajectories, Daniel J. Simon Sep 1996

Globally Optimal Periodic Robot Joint Trajectories, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

This paper presents a new method for the planning of robot trajectories. The method presented assumes that joint-space knots have been generated from Cartesian knots by an inverse kinematics algorithm. The method is based on the globally optimal periodic interpolation scheme derived by Schoenberg, and thus is particularly suited for periodic robot motions. Of all possible periodic joint trajectories which pass through a specified set of knots, the trajectory derived in this paper is the ‘best’. The performance criterion used is the integral (over one period) of a combination of the square of the joint velocity and the square of …

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Terminal Sliding Mode Control For Rigid Robotic Manipulators With Uncertain Dynamics, Nicola Ritter Jan 1996

Terminal Sliding Mode Control For Rigid Robotic Manipulators With Uncertain Dynamics, Nicola Ritter

Theses: Doctorates and Masters

This thesis presents two new adaptive control laws that use the terminal sliding mode technique for the tracking problem of rigid robotic manipulators with non-linearities, dynamic couplings and uncertain parameters. The first law provides a robust scheme which uses several properties of rigid robotic mauipulators and adaptively adjusts seven uncertain parameter bounds. The law ensures finite time error convergence to the system origin and is simple to implement The second law treats the manipulator as a partially known system. The known dynamics are used to build a nominal control law and the effects of unknown system dynamics arc compensated for …

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Book Review: Reasoning Agents In A Dynamic World: The Frame Problem. Kenneth M. Ford And Patrick J. Hayes, Eds.,, Jozsef A. Toth Jan 1995

Book Review: Reasoning Agents In A Dynamic World: The Frame Problem. Kenneth M. Ford And Patrick J. Hayes, Eds.,, Jozsef A. Toth

Jozsef A Toth Ph.D.

No abstract provided.

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Robust Decentralised Variable Structure Control For Rigid Robotic Manipulators, Thasapalan Kuhan Jan 1995

Robust Decentralised Variable Structure Control For Rigid Robotic Manipulators, Thasapalan Kuhan

Theses : Honours

In this thesis, the problem of robust variable structure control for non-linear rigid robotic manipulators is investigated. Robustness and convergence results are presented for variable structure control systems of robotic manipulators with bounded unknown disturbances, nonlinearities, dynamical couplings and parameter uncertainties. The major outcomes of the work described in this thesis are summarised as given below. The basic variable structure theory is surveyed, and some basic ideas such as sliding mode designs, robustness analysis and control1er design methods for linear or non-linear systems are reviewed. Three recent variable structure control schemes for robotic manipulators are discussed and compared to highlight …

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Nonlinear Transient Dynamics Of Flexible Robots, Mohamed Fouad Abdel Wahab Jan 1994

Nonlinear Transient Dynamics Of Flexible Robots, Mohamed Fouad Abdel Wahab

Archived Theses and Dissertations

No abstract provided.

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Variable Structure End Point Control Of A Flexible Manipulator, Shailaja Chenumalla, Sahjendra N. Singh Jul 1993

Variable Structure End Point Control Of A Flexible Manipulator, Shailaja Chenumalla, Sahjendra N. Singh

Electrical & Computer Engineering Faculty Research

We treat the question of control and stabilization of the elastic multibody system developed in the Phillips Laboratory, Edwards Air Force Base, California. The controlled output is judiciously chosen such that the zero dynamics are stable or almost stable. A variable structure control (VSC) law is derived for the end point trajectory control. Although, the VSC law accomplishes precise end point tracking, elastic modes are excited during the maneuver of the arm. A Linear stabilizer is designed for the final capture of the terminal state.

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Tolerance Specification Of Robot Kinematic Parameters Using An Experimental Design Technique, Y.H. Andrew Liou, Paul P. Lin, Richard R. Lindeke, Hsiang-Dih Chiang Jun 1993

Tolerance Specification Of Robot Kinematic Parameters Using An Experimental Design Technique, Y.H. Andrew Liou, Paul P. Lin, Richard R. Lindeke, Hsiang-Dih Chiang

Mechanical Engineering Faculty Publications

This paper presents the tolerance specification of robot kinematic parameters using the Taguchi method. The concept of employing inner and outer orthogonal arrays to identify the significant parameters and select the optimal tolerance range for each parameter is proposed. The performance measure based on signal-to-noise ratios (S/N) using the Taguchi method is validated by Monte Carlo simulations. Finally, a step-by-step tolerance specification methodology is developed and illustrated with a planar two-link manipulator and a five-degree-of-freedom Rhino robot.

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The Application Of Neural Networks To Optimal Robot Trajectory Planning, Daniel J. Simon May 1993

The Application Of Neural Networks To Optimal Robot Trajectory Planning, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

Interpolation of minimum jerk robot joint trajectories through an arbitrary number of knots is realized using a hardwired neural network. Minimum jerk joint trajectories are desirable for their similarity to human joint movements and their amenability to accurate tracking. The resultant trajectories are numerical rather than analytic functions of time. This application formulates the interpolation problem as a constrained quadratic minimization problem over a continuous joint angle domain and a discrete time domain. Time is discretized according to the robot controller rate. The neuron outputs define the joint angles (one neuron for each discrete value of time) and the Lagrange …

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Suboptimal Robot Joint Interpolation Within User-Specified Knot Tolerances, Daniel J. Simon, Can Isik May 1993

Suboptimal Robot Joint Interpolation Within User-Specified Knot Tolerances, Daniel J. Simon, Can Isik

Electrical and Computer Engineering Faculty Publications

Approximation of a desired robot path can be accomplished by interpolating a curve through a sequence of joint-space knots. A smooth interpolated trajectory can be realized by using trigonometric splines. But, sometimes the joint trajectory is not required to exactly pass through the given knots. The knots may rather be centers of tolerances near which the trajectory is required to pass. In this article, we optimize trigonometric splines through a given set of knots subject to user-specified knot tolerances. The contribution of this article is the straightforward way in which intermediate constraints (i.e., knot angles) are incorporated into the parameter …

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An Efficient Technique For Finding The Desired Global Optimum Of Robotic Joint Displacement, Paul P. Lin, An-Jen J. Yang Dec 1992

An Efficient Technique For Finding The Desired Global Optimum Of Robotic Joint Displacement, Paul P. Lin, An-Jen J. Yang

Mechanical Engineering Faculty Publications

For an industrial robot on a daily operation basis such as pick and place, it is desired to minimize the robotic joint displacements when moving the robot from one location to another. The objective of the optimization here is to simultaneously minimize a robot end effector's positional error and the robotic joint displacements. By modifying the searching algorithm in the existing complex optimization method, this article presents a technique for finding the desired global optimum solution more efficiently. To compare the optimum searching capability between the proposed and existing searching algorithms, a modified Himmelblau's function is used as an objective …

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An Improved Method For Online Calculation And Compensation Of The Static Deflection At A Robot End-Effector, Paul P. Lin, Hsiang-Dih Chiang, Xiu Xun Cui Apr 1991

An Improved Method For Online Calculation And Compensation Of The Static Deflection At A Robot End-Effector, Paul P. Lin, Hsiang-Dih Chiang, Xiu Xun Cui

Mechanical Engineering Faculty Publications

Traditionally, robotic deflection analysis for a low-weight robot has been performed based on an assumption that each link is treated as a cantilever beam, which leads to no angular deflection at a joint. In practice, a robotic intermediate joint is linearly and angulary deflected when a load is applied at the end-effector. It is found in this study that the additional link deflection resulting from the angular deflection of a robotic revolute joint substantially contributes to the end-effector's total deflection. This article presents an improved method via a combination of classical beam theory, energy methods and the concepts of differential …

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Two Dimensional And Three Dimensional Path Planning In Robotics, Hyun Suk Kim Jan 1988

Two Dimensional And Three Dimensional Path Planning In Robotics, Hyun Suk Kim

Dissertations and Theses

A methodology for 2D and 3D collision free path planning algorithm in a structured environment is presented. The isolated free convex areas are represented as a nodes in a graph, and a graph traversal strategy that dynamically allocates costs to graph path is used. Modification of the algorithm for small computational time and optimality is discussed. The 3D path planning is done in the three orthogonal two-dimensional projections of a 3D environment. Collision checking to increase the optimality for 3D paths is done in each of the three orthogonal two-dimensional subspaces.

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Impact Of Automation On Process Control Decision-Making, Steven M. Miller, Susan R. Bereiter Jan 1987

Impact Of Automation On Process Control Decision-Making, Steven M. Miller, Susan R. Bereiter

Research Collection School Of Computing and Information Systems

This paper investigates changes in the process control of a vehicle assembly plant which had been modernized from a principally manual procedure to one that uses programmable automation extensively. Process control is defined as the information flow and decision-making required to perform basic process operations. We investigate the effects of implementing a computer-integrated production system on the amount and types of process control decision-making and on the distribution of process control decision-making between humans and machines. After automation, the emphasis on decisions regarding product quality specifications increased and the emphasis on decisions related to flexibility in handling a variety of …

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Computers And Robotics, Wayne Tinga Jun 1985

Computers And Robotics, Wayne Tinga

Pro Rege

No abstract provided.

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Impacts Of Robotics And Flexible Manufacturing Technologies On Manufacturing Costs And Employment, Steven M. Miller Jan 1985

Impacts Of Robotics And Flexible Manufacturing Technologies On Manufacturing Costs And Employment, Steven M. Miller

Research Collection School Of Computing and Information Systems

The issues analyzed in this paper are the extent to which unit costs and production labor requirements might be reduced in manufacturing industries if there is more widespread use of industrial robots and flexible systems. The analysis is reported in detail in Miller (1983). These issues are analyzed from two different perspectives. The technological focus of the first perspective is narrowly confined to the use of robotic manipulators. It is assumed that robotic manipulators will be “retrofitted” into existing production facilities without making major changes in the organization of production within the factory, other than modifying individual work stations so …

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Robotic Realities: Near Term Prospects And Problems, Robert U. Ayres, Steven M. Miller Nov 1983

Robotic Realities: Near Term Prospects And Problems, Robert U. Ayres, Steven M. Miller

Research Collection School Of Computing and Information Systems

Industrial robots are automation, but with a difference. Other machine tools are extensions of human capabilities, while robots are seen mainly as substitutes for human workers. Robots will find most of their industrial applications during the next decade or two in the metal-working sectors, where they will begin to displace semiskilled machine operatives in medium to large batch production operations. They cannot substitute for skilled machinists or other workers doing nonroutine jobs, or specialized, dedicated hard automation used in mass production. The current generation of robots, lacking sensory data processing and interpretation capabilities, can potentially replace up to 1.3 million …

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Robotics And The Conservation Of Human Resources, Robert U. Ayres, Steven M. Miller Jan 1982

Robotics And The Conservation Of Human Resources, Robert U. Ayres, Steven M. Miller

Research Collection School Of Computing and Information Systems

Due to rapid expansion in the field of robotics, policy issues have arisen in regard to developing human skills to deal with the new technology and to deal with the obsolescent human skills which are the inevitable result of this growth pattern. Industrialists, educators, union leaders, and government officials must work cooperatively to insure that the coming changes are made with minimum disruption. Improved training methods and courses have to be developed for the skills needed to control, manage and supervise the new machines. Some of the ways in which this can be accomplished are through offering financial incentives for …

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