Person:

Book, Wayne J.

Permanent Link

https://hdl.handle.net/1853/71109

Associated Organization(s)

Organizational Unit

George W. Woodruff School of Mechanical Engineering

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Now showing 1 - 10 of 10

Force reflecting teleoperation with adaptive impedance control

(Georgia Institute of Technology, 2004-02) Love, Lonnie J. ; Book, Wayne J.

Experimentation and a survey of the literature clearly show that contact stability in a force reflecting teleoperation system requires high levels of damping on the master robot. However, excessive damping increases the energy required by an operator for commanding motion. The objective of this paper is to describe a new force reflecting teleoperation methodology that reduces operator energy requirements without sacrificing stability. We begin by describing a new approach to modeling and identifying the remote environment bf the teleoperation system. We combine a conventional Multi-Input, Multi-Output Recursive Least Squares (MIMO-RLS) system identification, identifying in real-time the remote environment impedance, with a discretized representation 'of the remote environment. This methodology generates a time-varying, position dependent representation of the remote environment dynamics. Next, we adapt the target impedance of the master robot with respect to the dynamic model of the remote environment. The environment estimation and impedance adaptation are execute simultaneously and in real time. We demonstrate, through experimentation, that this approach significantly reduces the energy required by an operator to execute remote tasks while simultaneously providing sufficient damping to ensure contact stability.
Adaptive impedance control for bilateral teleoperation of long reach flexible manipulators

(Georgia Institute of Technology, 1996-07) Love, Lonnie J. ; Book, Wayne J.

Current applications in the field of telerobotics, such as space based assembly and nuclear waste remediation, require the use of long reach manipulators. These robots are characterized by their large workspace and reduced mass. Unfortunately, this reduction in mass increases structural compliance making these robots susceptible to vibration. Until recently, no attempt has been made to provide the operator any type of force reflection due to the compliance of the slave robot. This research addresses the control of bilateral teleoperation systems that use long reach flexible manipulators. Experiments indicate that the compliance of the slave robot directly affects the stability of the teleoperation system. Our study suggests that this may be controlled by increasing the damping on the master robot. This increase in target damping increases the effort an operator must exert during the execution ofa task. To circumvent this limitation, the authors propose an adaptive impedance control paradigm. A new teleoperation strategy adapts the target impedance of the master robot to variations in the identified impedance of the remote environment coupled to the slave robot. Experiments suggest increased performance due to a decrease in the power the operator must provide during the execution of a task.
A Novel Teleoperated Long-Reach Manipulator Testbed and its Remote Capabilities via the Internet

(Georgia Institute of Technology, 1996-06) Lane, Hobson ; Love, Lonnie J. ; Magee, David P. ; Obergfell, Klaus ; Book, Wayne J.

During the 1995 DOE Robotics Forum at Albuquerque, New Mexico, Georgia Tech's Intelligent Machine Dynamics Laboratory demonstrated remote display capabilities of its telemanipulated long-reach manipulator testbed through the Internet. This paper describes the testbed and addresses the methods, limitations, and capabilities of remote operations.
Command filtering and path planning for remote manipulation of a long reach flexible robot

(Georgia Institute of Technology, 1996-04) Love, Lonnie J. ; Book, Wayne J.

We focus on the fusion of autonomous and teleoperated commands. This combination provides full use of the robot's workspace without requiring large motion amplification between a master and slave robot. Combining autonomous and teleoperated commands provides the potential for large variations in the commanded momentum of the flexible robot. These variations excite the lightly damped, low resonant frequencies associated with these manipulators. Two techniques are proposed to reduce the vibration during sudden stops in the commanded motion of a flexible manipulator. First a new command filtering approach that permits shorter delay times than standard input shaping methods is presented. Next, we propose dynamic alteration of the desired trajectory. Our investigation shows that filtering techniques exhibit an oscillatory response, more so than standard PD control algorithms, during hard stopping conditions. However the shorter time delay filtering algorithm has less vibration than standard input shaping techniques. Furthermore, any vibration may be eliminated by commanding the robot to decelerate instead of immediately stopping the motion.
Control methods for seamless teleoperation mode transfer and emergency stops using long reach, flexible manipulators

(Georgia Institute of Technology, 1996-04) Book, Wayne J. ; Love, Lonnie J.
Contact Stability Analysis of Virtual Walls

(Georgia Institute of Technology, 1995-11) Love, Lonnie J. ; Book, Wayne J.

Haptic interfaces are mechanical systems coupled to humans. These devices provide a method of relaying mechanical information between a human and a computer generated environment. A basic element in any virtual environment is the virtual wall. The problem addressed in this research is the stability of haptic interfaces when simulating virtual walls. Many researchers have recently published reports describing an un-modeled vibration experienced when attempting to simulate stiff surfaces. This investigation focuses on the structure of the control algorithm and its discrete time implementation. A computed torque method of impedance control provides robust performance, but is limited due to discrete time implementation. Bounds on the target impedance are defined though Jury analysis.
Environment Estimation for Enhanced Impedance Control

(Georgia Institute of Technology, 1995-05) Love, Lonnie J. ; Book, Wayne J.

Impedance control is a popular method of controlling the dynamic response a robot has to external forces. The advantage of such a control paradigm is the ability to manipulate in both unconstrained and constrained environments. Unlike hybrid control methods that attempt to control forces and motions in orthogonal directions, impedance control consists of a single control law that accommodates external forces. One problem associated with such a controller is the selection of the robot's target impedance. This paper illustrates, through analysis and experimentation, the shortcoming of improper target impedance selection. The integration of a real time estimate of the robot's environment with the impedance controller resolves this problem. Experimental results illustrate improved performance during the transition from unconstrained to constrained manipulation.
Design and Control of a Multiple Degree of Freedom Haptic Interface

(Georgia Institute of Technology, 1994-11) Love, Lonnie J. ; Book, Wayne J.

The role of robotics in society is no longer restricted to assembly and manufacturing. Robots are finding their way into a wide spectrum of tasks that directly link human and machine. Haptic interfaces are robots that are physically coupled to humans and produce desired tactile stimulation. These devices are integrated into active joystick control for aircraft, bilateral teleoperation, robotic assisted surgery and human rehabilitation and training. This paper discusses the design and control of a new haptic interface at the Georgia Institute of Technology. HURBIRT (Human Robot Bilateral Research Tool) is a two degree of freedom planar manipulator used to investigate control issue in teleoperation and human machine interaction.
A comparison of joint control algorithms for teleoperated pick and place tasks using a flexible manipulator

(Georgia Institute of Technology, 1994-10) Love, Lonnie J. ; Magee, David P. ; Book, Wayne J.

This paper presents initial results of an on going study of robot control algorithms used for teleoperation of long reach manipulators. The focus of the paper is the effect of the slave robot control algorithm on the performance of a teleoperation schemes that uses long reach, flexible manipulators. This study investigates the influence of PD, PD with input shaping, and PD with modified command filtering on pick and place teleoperation tasks. Data from 90 trials using 6 operators is used in an attempt to identify any increase in performance resulting from the use of any of the above control schemes. The results of this investigation indicate an increase in performance, based upon a combination of interaction forces and task execution time, of teleoperated pick and place tasks when a flexible robot uses either PD with input shaping or PD with modified command filtering.
A Teleoperation Testbed for Nuclear Waste Restoration

(Georgia Institute of Technology, 1994-08) Book, Wayne J. ; Love, Lonnie J. ; Farah, Michel

This paper presents the design and operation of a new teleoperation testbed currently under investigation at the Georgia Institute of Technology. This laboratory will enable researchers to investigate a wide range of issues concerning nuclear waste restoration. The focus of the project is to determine what factors effect the performance of human interaction in teleoperation. These factors include an investigation of various robot control algorithms, the effect of unilateral and bilateral information flow, the role of compliance oflong reach arms in teleoperation, and the influence of various queues in training and performance. Experiments and preliminary results concentrating on the significance of audible sounds in teleoperation are presented.