Author name cluster

Christopher Lee 0001

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

6 papers

1 author row

ICRA Conference 2000 Conference Paper

Trajectory Fitting with Smoothing Splines using Velocity Information

Christopher Lee 0001
Yangsheng Xu

We present a derivation for a spline smoother which takes into account local velocity information. This smoother is well suited for finding a best-fit trajectory from multiple example trajectories and is thus useful in applications such as programming by demonstration and online gesture recognition for teleoperation. Currently available smoothers are designed to consider only position information and not local velocity information, and are thus less suited for smoothing trajectories over time of dynamic systems.

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ICRA Conference 1998 Conference Paper

Message-Based Evaluation for High-Level Robot Control

Christopher Lee 0001
Yangsheng Xu

In this paper, we present a method for high-level control of robots whose low-level software is based on dynamically reconfigurable, reusable real-time software modules. Our approach is to use an embedded interpreter for a general-purpose programming language to direct the operation of the low-level modules toward meeting the task-level goals of the robot. To this end, we present RSK, a virtual-machine kernel implementing a scheme interpreter capable of hard real-time operation, and employing a method of code execution we call "message-based evaluation" (MBE). MBE is a novel combination of a traditional code execution model and a message-passing architecture, which simplifies the process of writing code for managing the robot's reconfigurable subsystem.

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IROS Conference 1998 Conference Paper

Reduced-dimension representations of human performance data for human-to-robot skill transfer

Christopher Lee 0001
Yangsheng Xu

Despite the large amount of research currently directed toward programming robots by demonstration, a significant problem with this method of human-to-robot skill transfer has not yet been addressed: developing representations of human performances which isolate the intrinsic dimensions of the performances (and thus the skills which guide them) within high-dimensional, raw human performance data. In this paper we propose the use of three methods for representing high-dimensional human performance data within lower-dimensional spaces: principal component analysis (PCA), nonlinear principal component analysis (NLPCA), and sequential nonlinear principal component analysis (SNLPCA). We compare the appropriateness of these methods for modeling a simple human grasping operation.

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ICRA Conference 1996 Conference Paper

A separable combination of wheeled rover and arm mechanism: (DM) 2

Yangsheng Xu
Christopher Lee 0001
H. Benjamin Brown

We present a novel mobile manipulator concept called the dual-use mobile detachable manipulator, or (DM)/sup 2/, for early construction and maintenance tasks in lunar stations. The robot consists of a wheeled rover, or mobile base and a detachable manipulator arm. The arm is symmetric, with a gripper at each end. When the arm attaches to the mobile base by grasping a handle with one of its grippers, the robot becomes a mobile manipulator and can perform exploration tasks such as collecting soil samples, surveying the lunar surface, and transporting tools and supplies. When the robot nears a lunar center structure such as a manufacturing center or a fuel tank, the manipulator arm can detach from the base and walk hand-over-hand, by grasping a series of handles on the structure, to perform tasks such as structure inspection, parts delivery, and simple assembly tasks. The paper discusses the concept and its advantages, the system under development, and its software architecture.

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ICRA Conference 1996 Conference Paper

Online, interactive learning of gestures for human/robot interfaces

Christopher Lee 0001
Yangsheng Xu

We have developed a gesture recognition system, based on hidden Markov models, which can interactively recognize gestures and perform online learning of new gestures. In addition, it is able to update its model of a gesture iteratively with each example it recognizes. This system has demonstrated reliable recognition of 14 different gestures after only one or two examples of each. The system is currently interfaced to a Cyberglove for use in recognition of gestures from the sign language alphabet. The system is being implemented as part of an interactive interface for robot teleoperation and programming by example.

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IROS Conference 1995 Conference Paper

Experimental study of an underactuated manipulator

Marcel Bergerman
Christopher Lee 0001
Yangsheng Xu

Underactuated manipulators are a class of robotic mechanisms where passive joints are present. By controlling only the motion of the active joints, it is possible to control the entire system. Our goal is to develop control schemes using both classical nonlinear and modem learning techniques for underactuated manipulators. To examine the validity of the approaches, we developed an experimental setup known as U-ARM, or underactuated robot manipulator. In this paper we present the hardware development, dynamic parameters, control software and experimental results of real-time control of the U-ARM.

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