Author name cluster

Thomas C. Henderson

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.

21 papers

2 author rows

ICRA Conference 2025 Conference Paper

The Automation of Uncrewed Aircraft Systems Traffic Management Calibration Based on Experimental Platform Data

Thomas C. Henderson
David Sacharny
Chad Mello
William Raley

Many countries are developing an Urban Air Mobility (UAM) capability defining an Uncrewed Aircraft Systems (UAS) Traffic Management (UTM) architecture to allow safe UAS services in urban environments (e. g. , delivery, inspection, air taxis, etc.). The main considerations are air worthiness, operator certification, air traffic management, C2 Link, detect and avoid (DAA), safety management, and security. In addition, if thousands of simultaneous UAS flights are to be achieved, it is not possible for them to be controlled individually by human operators. This makes it necessary to have a rigorous and safe automation methodology to handle such a number of flights. A lane-based airspace structure has been proposed which reduces the complexity of strategic deconfliction by providing UAS agents with a set of pre-defined airway corridors called lanes [1], [2]. This yields collateral benefits including UAS information privacy, robust contingency handling exploiting the lane structure, as well as improved observability and control of the air space. A robust set of UTM parameters and policies must be determined based on the performance characteristics of the deployed UAS platforms, and a methodology which constitutes a first step toward this end is proposed and demonstrated here. In order to realize this approach, a set of initial experiments have been performed to determine the constraints imposed by the UTM on UAS platform capabilities and vice versa. Initial implementation parameters and policies are defined. The major contribution here is a methodology to calibrate UTM safety parameters (e. g. , headway, platform speed) in terms of specific platform models' operational characteristics. That is, UTM parameters are a function of platform and not some arbitrarily imposed values. Safety uncertainty is then characterized by the calibration method.

IROS Conference 2014 Conference Paper

Received signal strength based bearing-only robot navigation in a sensor network field

Nikhil Deshpande
Edward Grant
Mark Draelos
Thomas C. Henderson

This paper presents a low-complexity, novel approach to wireless sensor network (WSN) assisted autonomous mobile robot (AMR) navigation. The goal is to have an AMR navigate to a target location using only the information inherent to WSNs, i. e. , topology of the WSN and received signal strength (RSS) information, while executing an efficient navigation path. Here, the AMR has neither the location information for the WSN, nor any sophisticated ranging equipment for prior mapping. Two schemes are proposed utilizing particle filtering based bearing estimation with RSS values obtained from directional antennas. Real-world experiments demonstrate the effectiveness of the proposed schemes. In the basic node-to-node navigation scheme, the bearing-only particle filtering reduces trajectory length by 11. 7% (indoors) and 15% (outdoors), when compared to using raw bearing measurements. The advanced scheme further reduces the trajectory length by 22. 8% (indoors) and 19. 8% (outdoors), as compared to the basic scheme. The mechanisms exploit the low-cost, low-complexity advantages of the WSNs to provide an effective method for map-less and ranging-less navigation.

ICRA Conference 2012 Conference Paper

Target-directed navigation using wireless sensor networks and implicit surface interpolation

Nikhil Deshpande
Edward Grant
Thomas C. Henderson

This paper extends the novel research for event localization and target-directed navigation using a deployed wireless sensor network (WSN) [4]. The goal is to have an autonomous mobile robot (AMR) navigate to a target-location by: (i) producing an artificial magnitude distribution within the WSN-covered region, and (ii) having the AMR use the pseudo-gradient from the interpolated distribution in its neighborhood, as it moves towards the target location. Implicit surfaces are used to interpolate the artificial distribution. This scheme only uses the topology of the WSN and received signal strength (RSS) to estimate an efficient navigation path for the AMR. Here, the AMR does not require global coordinates for the region, as it relies on local, neighborhood information alone to navigate. The performance of the scheme is analyzed with hardware experiments and in simulation, using a variety of node-densities and with increasing levels of noise to ensure robustness.

IROS Conference 2007 Conference Paper

Computational sensor networks

Thomas C. Henderson
Christopher A. Sikorski
Edward Grant
Kyle Luthy

We propose computational sensor networks as a methodology to exploit models of physical phenomena in order to better understand the structure of the sensor network. To do so, it is necessary to relate changes in the sensed variables (e. g. , temperature) to the aspect of interest in the sensor network (e. g. , sensor node position, sensor bias, etc.), and to develop a computational method for its solution. As an example, we describe the use of the heat equation to solve the sensor localization problem. Simulation and physical experiments are described.

ICRA Conference 2007 Conference Paper

Leveraging RSSI for Robotic Repair of Disconnected Wireless Sensor Networks

Kyle Luthy
Edward Grant
Thomas C. Henderson

Many recent deployments of environmental sensor networks have focused on obtaining measurements across large and inhospitable areas. With increasing scale it becomes impractical to deploy or maintain such systems by hand. This paper evaluates large scale network disconnectivity and highlights the underlying issues related to the environment and node characteristics. Furthermore, it examines how a low cost and adaptive method of robotic repair can be applied to large area networks using received signal strength measurements for simple navigation and placement.

ICRA Conference 2004 Conference Paper

Dynamic Leadership Protocol for S-nets

Gregory J. Barlow
Thomas C. Henderson
Andrew L. Nelson
Edward Grant

Smart Sensor Networks (S-nets) are groups of stationary agents (S-elements) which provide distributed sensing, computation, and communication in an environment. In order to integrate information from individual agents and to efficiently transmit this information to other agents, these devices must be able to create local groups (S-clusters). A leadership protocol that creates static clusters has been previously proposed. Here, we further develop this protocol to allow for dynamic cluster updating. This accommodates on-the-fly network re-organization in response to environmental disturbances or the gain or loss of S-elements. We outline an informal argument for the correctness of this revised protocol. We describe our embedded system implementation of the leadership protocol in simulation and using a colony of robots. Finally, we present results demonstrating both implementations.

IROS Conference 2004 Conference Paper

Gradient calculation in sensor networks

Thomas C. Henderson
Eddie Grant

Sensor networks are comprised of devices having the ability to communicate, compute and sense the environment. A wide range of information processing tasks has been studied for such networks, including operating systems, issues, architecture optimization, and distributed data processing. In this paper, we analyze and compare four different techniques to estimate the gradient of the function represented by the sensor samples. These include: (GA1) a simple device ID defined direction, (GA2) directional derivative, (GA3) polynomial approximation with a plane, and (GA4) polynomial approximation with a quadratic. We compare these based on density of devices per unit area, and noise in the position and sensed data. The interesting result is that GA3 significantly outperforms the other algorithms, although GA1 performs very well and is much easier to compute than the others.

ICRA Conference 2004 Conference Paper

Reaction-diffusion Patterns in Smart Sensor Networks

Thomas C. Henderson
Ramya Venkataraman
Gyounghwa Choikim

We introduced the use of Taring's reaction-diffusion pattern formation to support high-level tasks in smart sensor networks (S-Nets). This has led us to explore various biologically motivated mechanisms. We address some issues that arise in trying to get reliable, efficient patterns in irregular grids with error in inter-node distances.

IROS Conference 2003 Conference Paper

A colony of robots using vision sensing and evolved neural controllers

Andrew L. Nelson
Edward Grant
Gregory J. Barlow
Thomas C. Henderson

This paper describes the development and testing of a new evolutionary robotics research test bed. The test bed consists of a colony of small computationally powerful mobile robots that use evolved neural network controllers and vision based sensors to generate team game-playing behaviors. The vision based sensors function by converting video images into range and object color data. Large evolvable neural network controllers use these sensor data to control mobile robots. The networks require 150 individual input connections to accommodate the processed video sensor data. Using evolutionary computing methods, the neural network based controllers were evolved to play the competitive team game Capture the Flag with teams of mobile robots. Neural controllers were evolved in simulation and transferred to real robots for physical verification. Sensor signals in the simulated environment are formatted to duplicate the processed real video sensor values rather than the raw video images. Robot controllers receive sensor signals and send actuator commands of the same format, whether they are driving physical robots in a real environment or simulated robots agents in an artificial environment. Evolved neural controllers can be transferred directly to the real mobile robots for testing and evaluation. Experimental results generated with this new evolutionary robotics research test bed are presented.

IROS Conference 2003 Conference Paper

From motes to Java stamps: smart sensor network testbeds

Thomas C. Henderson
Jong-Chun Park
Nate Smith
Richard Wright

We have proposed smart sensor networks (S-Nets) as an architecture and set of distributed algorithms to extract, interpret and exploit networked sensor devices. Heretofore, the development of this approach has been done in simulation. In this paper, we describe two complementary implementations of S-Nets: (1) on a set of Berkeley motes comprised of low-power 8-bit, 128 Kb memory processors, communication devices and sensors, and (2) on a set of JStamps having 32-bit controllers, 2 Mb of memory and native execution Java hardware.

ICRA Conference 1998 Conference Paper

Instrumented Logical Sensor Systems-Practice

Mohamed Dekhil
Thomas C. Henderson

In previous work (1993, 1996), we introduced the notion of instrumented logical sensor systems (ILSS) that are derived from a modeling and design methodology. The instrumented sensor approach is based on a sensori-computational model which defines the components of the sensor system in terms of their functionality, accuracy, robustness and efficiency. This approach provides a uniform specification language to define sensor systems as a composition of smaller, predefined components. From a software engineering standpoint, this addresses the issues of modularity, reusability, and reliability for building complex multisensor systems. In this paper, we demonstrate the practicality of this approach and discuss several design and implementation aspects in the context of mobile robot applications.

IROS Conference 1998 Conference Paper

Smart sensor snow

Thomas C. Henderson
Mohamed Dekhil
Scott Morris 0002
Yu Chen
William B. Thompson

We propose to deploy and exploit a large number of inexpensive sensors to obtain information or trigger actions over a wide geographic area. Sensors may be of diverse physical natures: acoustic, IR, seismic, chemical, magnetic, thermal, etc. We describe three major issues: (1) sensor distribution patterns, (2) local sensor frames, and (3) autonomous robot sensor snow exploitation techniques.

ICRA Conference 1996 Conference Paper

Sonar sensing strategies

Thomas C. Henderson
Beat D. Brüderlin
Mohamed Dekhil
Larry Schenkat
Larkin Veigel

Develops theoretical and practical techniques to recover the pose of planar surfaces with minimal sensor readings and motion. A proof is given that two sonar readings suffice to precisely locate a single planar surface that returns the sonar's signal. An implementation is described that takes into account the physical restrictions on actual Polaroid sensors and experiments are described based on actual Polaroid sensor data.

ICRA Conference 1995 Conference Paper

A Unifying Framework for Tolerance Analysis in Sensing, Design, and Manufacturing

Tarek M. Sobh
Thomas C. Henderson
Frédéric Zana

In this work we address the problem of tolerance representation and analysis across the domains of industrial inspection using sensed data, CAD design, and manufacturing. Instead of using geometric primitives in CAD models to define and represent tolerances, we propose the use of stronger methods that are completely based on the manufacturing knowledge for the objects to be inspected. We guide our sensing strategies based on the manufacturing process plans for the parts that are to be inspected and define, compute, and analyze the tolerances of the parts based on the uncertainty in the sensed data along the different toolpaths of the sensed part. We believe that our new approach is the best way to unify tolerances across sensing, CAD, and CAM, as it captures the manufacturing knowledge of the parts to be inspected, as opposed to just CAD geometric representations.

ICRA Conference 1995 Conference Paper

UPE: Utah Prototyping Enviroment for Robot Manipulators

Mohamed Dekhil
Tarek M. Sobh
Thomas C. Henderson
Robert Mecklenburg

Developing an environment that enables optimal and flexible design of robot manipulators using reconfigurable links, joints, actuators, and sensors is an essential step for efficient robot design and prototyping. Such an environment should have the right "mix" of software and hardware components for designing the physical parts and the controllers, and for the algorithmic control of the robot modules (kinematics, inverse kinematics, dynamics, trajectory planning, analog control and digital computer control). Specifying object-based communications and catalog mechanisms between the software modules, controllers, physical parts, CAD designs, and actuator and sensor components is a necessary step in the prototyping activities. In this paper the authors propose a flexible prototyping environment for robot manipulators with the required subsystems and interfaces between the different components of this environment.

ICRA Conference 1994 Conference Paper

URK: Utah Robot Kit - A 3-Link Robot Manipulator Prototype

Mohamed Dekhil
Tarek M. Sobh
Thomas C. Henderson

In designing robot manipulators, the interaction between several modules (S/W, VLSI, CAD, CAM, robotics, and control) illustrates an interdisciplinary prototyping environment that includes different types of information that are radically different but combined in a coordinated way. This paper describes the analysis and design of a 3-link robot manipulator prototype as part of a research project for building a prototyping environment for electromechanical systems. This prototype robot can be used as an educational tool in robotics and control classes. >

ICRA Conference 1988 Conference Paper

A control paradigm for general purpose manipulation systems

Roderic A. Grupen
Thomas C. Henderson

The authors' goal is the creation of a framework within which independent objectives of a manipulation process can be used to direct a manipulation strategy. The set of contacts that are applied to a task can be partitioned into subsets with independent objectives. A system of this sort is flexible enough to manage large numbers of contacts and to address manipulation tasks that require the removal and replacement of fingers. A simulator has been constructed, and results of its application to position synthesis for initial grasps is presented. The manipulation testbed under construction at the University of Utah using the Utah/MIT dextrous hand are discussed. >

ICRA Conference 1988 Conference Paper

Parameter estimation and error analysis of range data

Prabhat K. Acharya
Thomas C. Henderson

Parameter estimation and error analysis techniques applicable to range data are discussed. Extracting surface parameters from noisy range data amounts to data reduction (parameter estimation) and error analysis, the most popular method for which is the least-squares method. Using least squares, it is shown how error in range data percolates upward to manifest itself in the value of each parameter that is calculated either directly or indirectly from data. In addition to estimating surface parameters, errors in the parameters themselves are estimated. The formalisms (with examples) for estimating error in a computed parameter and for combining two or more sets of parameter estimates into a single estimate are presented. >

ICRA Conference 1987 Conference Paper

CAD-based robotics

Thomas C. Henderson
Eliot Weitz
Charles D. Hansen
Roderic A. Grupen
C. C. Ho
Bir Bhanu

We describe an approach which facilitates and makes explicit the organization of the knowledge necessary to map robotic system requirements onto an appropriate assembly of algorlthms, processors, sensors, and actuators. In order to achieve this mapping several kinds of knowledge are needed. In this paper, we describe a system under development which exploits the Computer Aided Design (CAD) database in order to synthesize. •recognition Code for vision systems (both 2-D and 3-D), •grasping sites for simple parallel grippers, and •manipulation strategies for dextrous manipulation. We use an object-based approach and give an example application of the system to CAD-based 2-D vision.

AIJ Journal 1986 Journal Article

Arc and path consistency revisited

Roger Mohr
Thomas C. Henderson

Mackworth and Freuder have analyzed the time complexity of several constraint satisfaction algorithms [5]. We present here new algorithms for arc and path consistency and show that the arc consistency algorithm is optimal in time complexity and of the same-order space complexity as the earlier algorithms. A refined solution for the path consistency problem is proposed. However, the space complexity of the path consistency algorithm makes it practicable only for small problems. These algorithms are the result of the synthesis techniques used in alice (a general constraint satisfaction system) and local consistency methods [3].

ICRA Conference 1985 Conference Paper

CAGD based 3-D vision

Bir Bhanu
Thomas C. Henderson

This paper presents the initial results of our work in using the Computer Aided Geometric Design (CAGD) representations and models as a basis for the visual recognition of 3-D objects for robotic applications. We describe some techniques and algorithms which allow the generation of computer representations and geometric models of complicated realizable 3-D objects in a systematic manner. These representations and models are obtained using (a) available CAGD techniques, and (b) data acquired from various range finding techniques. As compared to previous work in machine vision, multiple hierarchical representations of an object obtained from geometric models can be used for finding orientation and position information.