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Book,
Wayne J.
Book,
Wayne J.
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ItemAutomated garment manufacturing system using novel sensing and actuation(Georgia Institute of Technology, 2010-07) Book, Wayne J. ; Winck, Ryder C. ; Killpack, Marc D. ; Huggins, James D. ; Dickerson, Stephen L. ; Jayaraman, Sundaresan ; Collins, Thomas R. ; Prado, Ronald J.Attempts to automate the sewing process of garment manufacture have employed substitutes for human guidance of fabric into somewhat conventional sewing machines. A new approach has been proposed and partially verified in prototype form. It consists of several subsystems responsible for 1) gross fabric motion, 2) precision detection of the fabric location and 3) exact placement of the needle in the fabric. Gross motion employs steerable rollers capable of moving the fabric. Fine fabric motion employs vision sensing technology to count threads in the fabric. Exact placement employs servo controlled dogs for moving the fabric to exactly place the needles. This paper will explain the concept and the extent of verification of its realization.
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ItemA novel approach to fabric control for automated sewing(Georgia Institute of Technology, 2009-07) Winck, Ryder C. ; Dickerson, Stephen L. ; Huggins, James D. ; Book, Wayne J.This paper describes a novel fabric manipulation method for fabric control during the sewing process. It addresses issues with past attempts concerning fabric position and tension control. The method described involves replacing the current sewing feed mechanism with a servo controlled manipulator to both feed and control the fabric. The manipulator is coupled with a machine vision system that tracks the threads of the fabric to provide real-time position control that is robust with respect to fabric deformations. A prototype of the manipulator is used to demonstrate the feasibility of the concept, reaching accelerations up to 27 g’s and following a closed loop trajectory with open loop control while operating in coordination with an industrial sewing machine. The system described also offers a general solution to high accuracy and high acceleration position control systems.
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ItemOn the transfer function modeling of flexible structures with distributed damping(Georgia Institute of Technology, 1986-12) Alberts, Thomas Edward ; Dickerson, Stephen L. ; Book, Wayne J.The authors have suggested the use of distributed passive damping via constrained viscoelastic layer surface treatments, as a means of augmenting active controllers for flexible structures. This enhances system stability and provides justification for the use of low order dynamic models and controllers. In previous work a co located transfer. function based upon experimental measurements was employed in root locus analysis of a system with passive damping. Here we present a method of deriving co located and non-colocated transfer functions for flexible systems with distributed damping. The (sandwich) flexible structure is modeled as though it was constructed of an equivalent homogeneous material exhibiting linear viscoelastic behavior. Transfer functions are obtained through solution of a modified form of the Bernoulli-Euler equation which is derived using the standard constitutive relationship between stress and strain for viscoelastic materials in place of Hook's law. General observations are made with regard to open loop pole and zero locations for colocated and non-colocated transfer functions. The effect of joint damping is also considered.
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ItemExperiments in augmenting active control of a flexible structure with passive damping(Georgia Institute of Technology, 1986-01) Alberts, Thomas Edward ; Book, Wayne J. ; Dickerson, Stephen L.Control ling the motion of large flexible structures through purely active measures can become cumbersome in terms of hardware and computation time requirements. Moreover, for any practical implementation, the need to limit the order of the system model and controller may lead to problems associated with spill over and modeling uncertainty. In many cases it is possible to augment active controllers using passive vibration control measures thereby relaxing the burden of active control. In this paper we discuss the results of an experimental investigation of using this highly practical scheme. The experimental system under consideration is a flexible arm that rotates in the horizontal plane when driven at its pinned end by a DC torque motor. Passive dampening is s provided by a constrained viscoelastic layer damping treatment. Experiments were performed to demonstrate the stabilizing effect of the damping treatment on a system using modal feedback and one using only colocated control. A root locus analysis of the colocated system substantiates the experimental results.
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ItemCombined approaches to lightweight arm utilization(Georgia Institute of Technology, 1985-11) Book, Wayne J. ; Dickerson, Stephen L. ; Hastings, Gordon Greene ; Cetinkunt, Sabri ; Alberts, Thomas EdwardIn order to use lightweight arms the combination of a number of new approaches in arm design and control may be necessary. This paper describes four complimentary research efforts and how their results will work together. The bracing strategy is proposed first as one scenario of arm usage. It braces the arm against a passive structure to increase rigidity during fine motions of the end effector. Large motions of the arm require path and trajectory planning. Research on minimum time motions that avoid unnecessarily exciting vibrations is described next. The damping of those vibrations that are excited can be accomplished through a combination of active modal feedback control and passive damping. The enhancement of the damping characteristics of arm structures is described. This is important for stable feedback control with actuators and controllers with limited bandwidth. Analytical and experimental results for constrained layer damping are described. in the context of the control problem. An active modal control has been implimented on a simple one link beam. As higher bandwidth is sought from this physical system deviations from the predicted results were observed. A refinement of the model to include anti-aliasing filter, sample-data, and amplifier effects explains the behavior as explained.
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ItemModeling and Control of Flexible Manipulators(Georgia Institute of Technology, 1985-06) Alberts, Thomas Edward ; Dickerson, Stephen L. ; Book, Wayne J.Methods to control manipulators with flexible structural members are presently sought by investigators to allow the design of lightweight, high-performance robotic manipulators. A survey of developments to date and an overview of current research activity in this area at Georgia Institute of Technology is presented. A straight forward method of modeling a simple single-link arm is included as an example. A scheme by which the first modes of vibration are actively controlled while higher modes are controlled/passively using a constrained viscoelastic layer treatment is described.
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ItemExperiments in Optimal Control of a Flexible Arm with Passive Damping(Georgia Institute of Technology, 1985-06) Alberts, Thomas Edward ; Hastings, Gordon Greene ; Book, Wayne J. ; Dickerson, Stephen L.This paper presents a hybrid active and passive control scheme for control ling the motion of a lightweight flexible arm. A straightforward development of LaGrange's equations using a series expansion of assumed flexible modes provides a time domain model for controller design. The active controller design was approached as a steady state linear quadratic continuous regulator. A constrained viscoelastic layer treatment was employed to achieve passive damping. The passive damping treatment serves to enhance the system's stability while providing sound justification for the use of a highly truncated dynamic model and reduced order controller. Initial experimental results comparing controller performance with and without passive damping demonstrate the merit of the proposed combined active/passive approach.
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ItemConsiderations in Selection of DC Motors for Lightweight Arms(Georgia Institute of Technology, 1984-06) Sangveraphunsiri, Viboon ; Book, Wayne J. ; Dickerson, Stephen L.This paper addresses the relationship between the weight of DC moving-coil permanent-magnet motors and the requirements for the driven motion. The requirements for motion are assumed to be made in terms of a maximum absolute velocity and a maximum absolute acceleration. A move consists of periods of maximum acceleration and periods of maximum velocity, so called trapezoidal velocity profiles. The load on the motor/drive-train is characterized by a maximum torque (or force) which is assumed to occur during a period of maximum acceleration. The DC motor is assumed to be limited by a maximum torque applied magnetically to the armature (essentially a maximum current) and by a maximum armature speed. Within these constraints simple procedures for identifying the lightest motors are given. An analysis of several series of popular motors is provided which defines the current state-of-the-art for such motors.
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ItemThree dimensional graphics station for computer integrated manufacturing research(Georgia Institute of Technology, 1984) Boulet, Joseph A. M. ; Book, Wayne J. ; Dickerson, Stephen L. ; Berry, John T.