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J.E. Colgate

Bio: J.E. Colgate is an academic researcher from Northwestern University. The author has contributed to research in topics: Haptic technology & Exoskeleton. The author has an hindex of 45, co-authored 109 publications receiving 7804 citations. Previous affiliations of J.E. Colgate include National University of Singapore & University of Florida.


Papers
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Proceedings ArticleDOI
08 May 1994
TL;DR: This paper addresses the performance of force-reflecting interfaces and suggests that an important measure of performance is the dynamic range of achievable impedances-"Z-Width"-and that an impedance is achievable if it satisfies a robustness property such as passivity.
Abstract: This paper addresses the performance of force-reflecting interfaces ("haptic displays"). The authors suggest that an important measure of performance is the dynamic range of achievable impedances-"Z-Width"-and that an impedance is achievable if it satisfies a robustness property such as passivity. Several factors affecting Z-Width-sample-and-hold, inherent interface dynamics, displacement sensor quantization, and velocity filtering-are discussed. A set of experiments designed to evaluate these factors is described and experimental results are presented. A striking result is that inherent interface damping exerts an overwhelming influence on Z-Width. >

709 citations

Journal ArticleDOI
TL;DR: This paper describes an approach to the design of ‘interaction controllers’ and contrasts this with an Approach to the Design of Approaches toDynamic interaction with the environment is fundamental to the process of manipulation.
Abstract: Dynamic interaction with the environment is fundamental to the process of manipulation. This paper describes an approach to the design of ‘interaction controllers’ and contrasts this with an approa...

611 citations

Proceedings ArticleDOI
05 Aug 1995
TL;DR: In this paper, the authors describe some of the challenges of creating realistic haptic perceptions of tool use and present a haptic display for training tool use, including collision detection and collision avoidance.
Abstract: Our group is interested in using haptic display for training tool use. Applications include training doctors to use tools during surgery, and training astronauts to use tools during EVA. This paper describes some of the challenges of creating realistic haptic perceptions of tool use. Many of these challenges stem from the importance of unilateral constraints during tool use. Unilateral constraints occur whenever rigid bodies collide, resisting the interpenetration of the bodies, but not holding the bodies together. To identify unilateral constraints, a tool/environment simulation must perform collision detection. To respond properly to a collision, the simulation must estimate the forces that ensue, and integrate the equations of motion. All of these computations must occur in real time, and the simulation as a whole must be stable (to ensure the user's safety). Approaches to these problems are described.

419 citations

Journal ArticleDOI
TL;DR: In this paper, the authors review clues to artificial swimmer design taken from fish physiology and formalize and review the control problems that must be solved by a robot fish, and exploit fish locomotion principles to address the truly difficult control challenges of station keeping under large perturbations.
Abstract: The bodies and brains of fish have evolved to achieve control objectives beyond the capabilities of current underwater vehicles. One route toward designing underwater vehicles with similar capabilities is to better understand fish physiological design and control strategies. This paper has two objectives: 1) to review clues to artificial swimmer design taken from fish physiology and 2) to formalize and review the control problems that must be solved by a robot fish. The goal is to exploit fish locomotion principles to address the truly difficult control challenges of station keeping under large perturbations, rapid maneuvering, power-efficient endurance swimming, and trajectory planning and tracking. The design and control of biomimetic swimming machines meeting these challenges will require state-of-the-art engineering and biology.

415 citations

Proceedings ArticleDOI
18 Sep 1993
TL;DR: A theoretical analysis of the implementation of stiff wall implementation is presented and the main result is a criterion for the passivity of a virtual wall in terms of two nondimensional parameters.
Abstract: The performance of a haptic interface is often reported in terms of the dynamic range of impedances it may represent. At the low end, the range is typically limited by inherent dynamics of the interface device, such as inertia and friction. At the high end, the range is typically limited by system stability. In a number of the applications, the principal limitation has proven to be the achievable upper limit on impedance. Therefore, a benchmark problem of considerable importance is the implementation of a stiff "wall". Contacting a wall may be described as the reversible transition from a region of very low impedance to one of very high impedance. A theoretical analysis (supplemented with discussion of experimental and simulation results) of stiff wall implementation is presented. The main result is a criterion for the passivity of a virtual wall in terms of two nondimensional parameters. >

371 citations


Cited by
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Journal ArticleDOI
01 Oct 1993
TL;DR: It is shown that a proper use of an four channels is of critical importance in achieving high performance telepresence in the sense of accurate transmission of task impedances to the operator.
Abstract: Tools for quantifying teleoperation system performance and stability when communication delays are present are provided A general multivariable system architecture is utilized which includes all four-types of data transmission between master and slave: force and velocity in both directions It is shown that a proper use of an four channels is of critical importance in achieving high performance telepresence in the sense of accurate transmission of task impedances to the operator It is also shown that transparency and robust stability (passivity) are conflicting design goals in teleoperation systems The analysis is illustrated by comparing transparency and stability in two common architectures, as well as a recent passivated approach and a new transparency-optimized architecture, using simplified one-degree-of-freedom examples >

2,083 citations

Journal ArticleDOI
TL;DR: In this article, the authors survey progress over the past 25 years in the development of microscale devices for pumping fluids and attempt to provide both a reference for micropump researchers and a resource for those outside the field who wish to identify the best micropumps for a particular application.
Abstract: We survey progress over the past 25 years in the development of microscale devices for pumping fluids. We attempt to provide both a reference for micropump researchers and a resource for those outside the field who wish to identify the best micropump for a particular application. Reciprocating displacement micropumps have been the subject of extensive research in both academia and the private sector and have been produced with a wide range of actuators, valve configurations and materials. Aperiodic displacement micropumps based on mechanisms such as localized phase change have been shown to be suitable for specialized applications. Electroosmotic micropumps exhibit favorable scaling and are promising for a variety of applications requiring high flow rates and pressures. Dynamic micropumps based on electrohydrodynamic and magnetohydrodynamic effects have also been developed. Much progress has been made, but with micropumps suitable for important applications still not available, this remains a fertile area for future research.

1,913 citations

Journal ArticleDOI
TL;DR: This survey addresses the subject of bilateral teleoperation, a research stream with more than 50 years of history and one that continues to be a fertile ground for theoretical exploration and many applications.

1,584 citations

Patent
19 Feb 1997
TL;DR: In this article, a system for performing minimally invasive cardiac procedures is described, which includes a pair of surgical instruments that are coupled to a robotic arms. But the system is not suitable for the handling of a large number of patients.
Abstract: A system for performing minimally invasive cardiac procedures. The system includes a pair of surgical instruments that are coupled to a pair of robotic arms. The instruments have end effectors that can be manipulated to hold and suture tissue. The robotic arms are coupled to a pair of master handles by a controller. The handles can be moved by the surgeon to produce a corresponding movement of the end effectors. The movement of the handles is scaled so that the end effectors have a corresponding movement that is different, typically smaller, than the movement performed by the hands of the surgeon. The scale factor is adjustable so that the surgeon can control the resolution of the end effector movement. The movement of the end effector can be controlled by an input button, so that the end effector only moves when the button is depressed by the surgeon. The input button allows the surgeon to adjust the position of the handles without moving the end effector, so that the handles can be moved to a more comfortable position. The system may also have a robotically controlled endoscope which allows the surgeon to remotely view the surgical site. A cardiac procedure can be performed by making small incisions in the patient's skin and inserting the instruments and endoscope into the patient. The surgeon manipulates the handles and moves the end effectors to perform a cardiac procedure such as a coronary artery bypass graft.

1,523 citations

Journal ArticleDOI
TL;DR: In this paper, the authors report the completion of four fundamental fluidic operations considered essential to build digital microfluidic circuits, which can be used for lab-on-a-chip or micro total analysis system (/spl mu/TAS): 1) creating, 2) transporting, 3) cutting, and 4) merging liquid droplets, all by electrowetting.
Abstract: Reports the completion of four fundamental fluidic operations considered essential to build digital microfluidic circuits, which can be used for lab-on-a-chip or micro total analysis system (/spl mu/TAS): 1) creating, 2) transporting, 3) cutting, and 4) merging liquid droplets, all by electrowetting, i.e., controlling the wetting property of the surface through electric potential. The surface used in this report is, more specifically, an electrode covered with dielectrics, hence, called electrowetting-on-dielectric (EWOD). All the fluidic movement is confined between two plates, which we call parallel-plate channel, rather than through closed channels or on open surfaces. While transporting and merging droplets are easily verified, we discover that there exists a design criterion for a given set of materials beyond which the droplet simply cannot be cut by EWOD mechanism. The condition for successful cutting is theoretically analyzed by examining the channel gap, the droplet size and the degree of contact angle change by electrowetting on dielectric (EWOD). A series of experiments is run and verifies the criterion.

1,522 citations