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Full-Text Articles in Engineering

Dynamic Modeling, Parameter Estimation And Control Of A Leg Prosthesis Test Robot, Hanz Richter, Daniel Simon, William Smith, Sergey Samorezov Dec 2015

Dynamic Modeling, Parameter Estimation And Control Of A Leg Prosthesis Test Robot, Hanz Richter, Daniel Simon, William Smith, Sergey Samorezov

Hanz Richter

Robotic testing can facilitate the development of new concepts, designs and control systems for prosthetic limbs. Human subject test clearances, safety and the lack of repeatability associated with human trials can be reduced or eliminated with automated testing, and test modalities are possible which are dangerous or inconvenient to attempt with patients. This paper describes the development, modeling, parameter estimation and control of a robot capable of reproducing two degree-of-freedom hip motion in the sagittal plane. Hip vertical displacement and thigh angle motion profiles are applied to a transfemoral prosthesis attached to the robot. A treadmill is used as walking …


Direction Of Slip Detection For A Biomimetic Tactile Sensor, Erik Engeberg, Morteza Vatani, Jae-Won Choi Apr 2015

Direction Of Slip Detection For A Biomimetic Tactile Sensor, Erik Engeberg, Morteza Vatani, Jae-Won Choi

Dr. Jae-Won Choi

A biomimetic tactile sensor (BTS) is developed from strips of electrically conductive carbon nanotubes (CNTs) mixed in a polymer matrix that is embedded within a flexible polyurethane shell. The mechanical compliance of the BTS is similar to the human fingertip. Experiments are performed which show that the BTS can be used to detect slip and the direction that slip occurs by examining the relative timing among force signals from adjacent strips of CNTs and the frequency content of the force signals. The BTS can also detect forces applied at distinct points on the surface of the BTS.


Effect Of Aircraft Datablock Complexity And Exposure Time On Performance Of Change Detection Task, Chen Ling, Lesheng Hua Apr 2015

Effect Of Aircraft Datablock Complexity And Exposure Time On Performance Of Change Detection Task, Chen Ling, Lesheng Hua

Dr. Chen Ling

Air traffic controllers constantly perform tasks of monitoring traffic situation and searching for conflict between aircrafts. One requirement for these tasks is being able to detect any changes in the aircraft status presented by aircraft datablock. In this study, we investigated the effects of aircraft datablock complexity and exposure time on the change detection task performance. Two types of datablock, six field datablock (6F-DB) and nine field datablock (9F-DB), were artificially designed. Ten participants learned the change detection taskwith aircraft datablocks for four days. Our results showed that datablock complexity and exposure time in the change detection task had direct …


Physical Intelligent Sensors, Pavan Bandhil, Sanjeevi Chitikeshi, Ajay Mahajan, Fernando Figueroa Apr 2015

Physical Intelligent Sensors, Pavan Bandhil, Sanjeevi Chitikeshi, Ajay Mahajan, Fernando Figueroa

Dr. Ajay Mahajan

This paper proposes the development of intelligent sensors as part of an integrated systems approach, i.e. one treats the sensors as a complete system with its own sensing hardware (the traditional sensor), A/D converters, processing and storage capabilities, software drivers, self-assessment algorithms, communication protocols and evolutionary methodologies that allow them to get better with time. Under a project being undertaken at the NASA s Stennis Space Center, an integrated framework is being developed for the intelligent monitoring of smart elements. These smart elements can be sensors, actuators or other devices. The immediate application is the monitoring of the rocket test …


A Novel Method To Create Intelligent Sensors With Learning Capabilities, Ajay Mahajan, Fernando Figueroa Apr 2015

A Novel Method To Create Intelligent Sensors With Learning Capabilities, Ajay Mahajan, Fernando Figueroa

Dr. Ajay Mahajan

A formal theory for the development of a generic model of an autonomous sensor is proposed and implemented. An autonomous sensor not only interprets the acquired data in accordance with an embedded expert system knowledge base, but is also capable of using this data to modify and enhance this knowledge base. Hence, the system is capable of learning and thereby improving its performance over time. The main objective of the model is to combine the capabilities of the physical sensor and an expert operator monitoring the sensor in real-time. The system has been successfully tested using various simulated data sets …


Getting It Right The First Time: Robot Mission Guarantees In The Presence Of Uncertainty, Damian Lyons, Ronald Arkin, Paramesh Nirmal, Shu Jiang, Tsung-Ming Liu, J Deeb Sep 2013

Getting It Right The First Time: Robot Mission Guarantees In The Presence Of Uncertainty, Damian Lyons, Ronald Arkin, Paramesh Nirmal, Shu Jiang, Tsung-Ming Liu, J Deeb

Peng Tang

Certain robot missions need to perform predictably in a physical environment that may only be poorly characterized in advance. We have previously developed an approach to establishing performance guarantees for behavior based controllers in a process-algebra framework. We extend that work here to include random variables, and we show how our prior results can be used to generate a Dynamic Bayesian Network for the coupled system of program and environment model. Verification is reduced to a filtering problem for this network. Finally, we present validation results that demonstrate the effectiveness of the verification of a multiple waypoint robot mission using …


Development Of A New Lagrangian Float For Studying Coastal Marine Ecosystems, Alex Schwithal, Chris Roman Jan 2013

Development Of A New Lagrangian Float For Studying Coastal Marine Ecosystems, Alex Schwithal, Chris Roman

Christopher N. Roman

This paper presents an overview and initial testing results for a shallow water Lagrangian float designed to operate in coastal settings. The presented effort addresses the two main characteristics of the shallow coastal environment that preclude the direct of use of many successfully deep water floats, namely the higher variation of water densities near the coast compared with the open ocean and the highly varied bathymetry. Our idea is to develop a high capacity dynamic auto-ballasting system that is able to compensate for the expected seawater density variation over a broad range of water temperatures and salinities while using measurements …


Concept Tests For A New Wire Flying Vehicle Designed To Achieve High Horizontal Resolution Profiling In Deep Water, Chris Roman, Dave Hebert Dec 2012

Concept Tests For A New Wire Flying Vehicle Designed To Achieve High Horizontal Resolution Profiling In Deep Water, Chris Roman, Dave Hebert

Christopher N. Roman

Efficiently profiling the water column to achieve both high vertical and horizontal resolution from a moving vessel in deep water is difficult. Current solutions, such as CTD tow-yos, moving vessel profilers, and undulating tow bodies, are limited by ship speed or water depth. As a consequence, it is difficult to obtain oceanographic sections with sufficient resolution to identify many relevant scales over the deeper sections of the water column. This paper presents a new concept for a profiling vehicle that slides up and down a towed wire in a controlled manner using the lift created by wing foils. The wings …


Roach: An Autonomous 2.4g Crawling Hexapod Robot, Aaron Hoover, Erik Steltz, Ronald Fearing Jul 2012

Roach: An Autonomous 2.4g Crawling Hexapod Robot, Aaron Hoover, Erik Steltz, Ronald Fearing

Aaron M. Hoover

This work presents the design, fabrication, and testing of a novel hexapedal walking millirobot using only two actuators. Fabricated from S2-glass reinforced composites and flexible polymer hinges using the smart composite microstructures (SCM) process, the robot is capable of speeds up to 1 body length/sec or approximately 3 cm/s. All power and control electronics are onboard and remote commands are enabled by an IrDA link. Actuation is provided by shape memory alloy wire. At 2.4 g including control electronics and battery, RoACH is the smallest and lightest autonomous legged robot produced to date.


Medic: A Legged Millirobot Utilizing Novel Obstacle Traversal, Nicholas Kohut, Aaron Hoover, Kevin Ma, Stanley Baek, Ronald Fearing Jul 2012

Medic: A Legged Millirobot Utilizing Novel Obstacle Traversal, Nicholas Kohut, Aaron Hoover, Kevin Ma, Stanley Baek, Ronald Fearing

Aaron M. Hoover

This work presents the design, fabrication, capabilities, and obstacle traversal mechanics of MEDIC (MillirobotEnabled Diagnostic of Integrated Circuits), a small legged robot able to overcome a varied array of obstacles. MEDIC features a hull that keeps its body in contact with the ground at all times, and uses only four actuators to move forward, turn, mount obstacles, and move in reverse. The chassis is fabricated using a Smart Composite Microstructures (SCM) approach and the robot is actuated by coiled Shape Memory Alloy (SMA). MEDIC also features a camera which will be useful for navigation in the future.


Systematic Study Of The Performance Of Small Robots On Controlled Laboratory Substrates, Chen Li, Aaron Hoover, Paul Birkmeyer, Paul Umbanhowar, Ronald Fearing, Daniel Goldman Jul 2012

Systematic Study Of The Performance Of Small Robots On Controlled Laboratory Substrates, Chen Li, Aaron Hoover, Paul Birkmeyer, Paul Umbanhowar, Ronald Fearing, Daniel Goldman

Aaron M. Hoover

The design of robots able to locomote effectively over a diversity of terrain requires detailed ground interaction models; unfortunately such models are lacking due to the complicated response of real world substrates which can yield and flow in response to loading. To advance our understanding of the relevant modeling and design issues, we conduct a comparative study of the performance of DASH and RoACH, two small, biologically inspired, six legged, lightweight (~10 cm, ~20 g) robots fabricated using the smart composite microstructure (SCM) process. We systematically examine performance of both robots on rigid and flowing substrates. Varying both ground properties …


Fast Scale Prototyping For Folded Millirobots, Aaron Hoover, Ronald Fearing Jul 2012

Fast Scale Prototyping For Folded Millirobots, Aaron Hoover, Ronald Fearing

Aaron M. Hoover

We present a set of tools and a process, making use of inexpensive and environmentally friendly materials, that enable the rapid realization of fully functional large scale prototypes of folded mobile millirobots. By mimicking the smart composite microstructure (SCM) process at a 2–10X scale using posterboard, and commonly available polymer films, we can realize a prototype design in a matter of minutes compared with days for a complicated SCM design at the small scale. The time savings enable a significantly shorter design cycle by allowing forimmediate discovery of design flaws and introduction of design improvements prior to beginning construction at …


A Rapidly Prototyped 2-Axis Positioning Stage For Microassembly Using Large Displacement Compliant Mechanisms, Aaron Hoover, Srinath Avadhanula, Richard Groff, Ronald Fearing Jul 2012

A Rapidly Prototyped 2-Axis Positioning Stage For Microassembly Using Large Displacement Compliant Mechanisms, Aaron Hoover, Srinath Avadhanula, Richard Groff, Ronald Fearing

Aaron M. Hoover

Compliant mechanisms provide an attractive alternative to conventional rigid mechanisms in the design of ultra low-cost precision positioning systems. The desirable performance characteristics of these mechanisms including freedom from backlash, long life, light weight, and ease of fabrication/assembly make them an ideal solution to the problem of inexpensive precision positioning for microassembly. This paper presents a design for a 2 axis precision positioning system which makes use of large displacement compliant mechanisms, a room temperature and pressure molding fabrication process, commodity hardware, and a piecewise linear interpolation compensation scheme to achieve positioning performance suitable for automated assembly of sub-centimeter robotic …


Analysis Of Off-Axis Performance Of Compliant Mechanisms With Applications To Mobile Millirobot Design, Aaron Hoover, Ronald Fearing Jul 2012

Analysis Of Off-Axis Performance Of Compliant Mechanisms With Applications To Mobile Millirobot Design, Aaron Hoover, Ronald Fearing

Aaron M. Hoover

We present an approach to quantifying the off-axis stiffness properties of parallel compliant mechanisms used in the design of mobile millirobots. By transforming the stiffness of individual flexure elements and rigid links comprising a compliant mechanism into a global coordinate system, we enable the formulation of an equivalent mechanism stiffness. Using that stiffness in concert with an energy-based performance metric, we predict theperformance of a compliant mechanism subjected to a prescribed set of forces in the global coordinate system. We analyze a flexure-based Sarrus linkage and use the performance metric to improve the design by adding topological redundancy. Finally, our …


Rapidly Prototyped Orthotweezers For Automated Microassembly, Aaron Hoover, Ronald Fearing Jul 2012

Rapidly Prototyped Orthotweezers For Automated Microassembly, Aaron Hoover, Ronald Fearing

Aaron M. Hoover

We describe the design, fabrication, and testing of an ultra-low cost orthotweezers system for microassembly. By utilizing rapid prototyping technology, compliant mechanisms, and commodity-grade actuators and sensors, we significantly reduce the complexity and cost of the previous Orthotweezers system without sacrificing functionality. With a force resolution of 0.7mN and a worst case mean positioning repeatability of 23 mum, the system is capable of dexterously manipulating rectangular parts with dimensions 200 mum times 200 mum times 100 mum. Such blocks can then be temporarily attached to thin, delicate, or oddly shaped parts to enable handling and ultimately assembly of micromechanical structures. …


Bio-Inspired Design And Dynamic Maneuverability Of A Minimally Actuated Six-Legged Robot, Aaron Hoover, Samuel Burden, Xiao-Yu Fu, S. Sastry, Ronald Fearing Jul 2012

Bio-Inspired Design And Dynamic Maneuverability Of A Minimally Actuated Six-Legged Robot, Aaron Hoover, Samuel Burden, Xiao-Yu Fu, S. Sastry, Ronald Fearing

Aaron M. Hoover

Rapidly running arthropods like cockroaches make use of passive dynamics to achieve remarkable locomotion performance with regard to stability, speed, and maneuverability. In this work, we take inspiration from these organisms to design, fabricate, and control a 10cm, 24 gram underactuated hexapedal robot capable of running at 14 body lengths per second and performing dynamic turning maneuvers. Our design relies on parallel kinematic mechanisms fabricated using the scaled smart composite microstructures (SCM) process and viscoelastic polymer legs with tunable stiffness. In addition to the novel robot design, we present experimental validation of the lateral leg spring (LLS) locomotion model's prediction …


Perimeter Patrol On Autonomous Surface Vehicles Using Marine Radar, Elena Oleynikova, Nicole Lee, Andrew Barry, Joseph Holler, David Barrett Jul 2012

Perimeter Patrol On Autonomous Surface Vehicles Using Marine Radar, Elena Oleynikova, Nicole Lee, Andrew Barry, Joseph Holler, David Barrett

David Barrett

Perimeter patrol enhances the utility of autonomous surface vehicles (ASVs) by enabling many security and scientific missions, including harbor protection, water sampling, and geological survey. We present a novel approach to perimeter patrol that uses only two sensors: commercial off-the-shelf available marine radar and the heading information from a GPS. Our algorithm performs computer vision morphological operations on the radarimage to find a suitable path around shore and choose an appropriate next waypoint. Our method has proved robust to a variety of field conditions, allowing us to demonstrate the autonomous navigation of a 3.5 km perimeter lake.


The Optimal Control Of A Flexible Hull Robotic Undersea Vehicle Propelled By An Oscillating Foil, David Barrett, Mark Grosenbaugh, Michael Triantafyllou Jul 2012

The Optimal Control Of A Flexible Hull Robotic Undersea Vehicle Propelled By An Oscillating Foil, David Barrett, Mark Grosenbaugh, Michael Triantafyllou

David Barrett

Determining the optimal swimming motion for a flexible hull robotic undersea vehicle propelled by an oscillating foil is an acutely complex problem involving the vehicle's body kinematics and the hydrodynamics of the surrounding water. The overall intractability of the hydrodynamics of a flexible body precludes a purely analytical solution. The immense size of the experimental variable space prevents a purely empirical one. In order to overcome both difficulties, we have developed a self-optimizing motion controller based on a genetic algorithm. This controller effectively uses evolutionary principles to exponentially optimize swimming performance.


Activity-Aware Mental Stress Detection Using Physiological Sensors, Feng-Tso Sun, Cynthia Kuo, Heng-Tze Cheng, Senaka Buthpitiya, Patricia Collins, Martin Griss Jan 2011

Activity-Aware Mental Stress Detection Using Physiological Sensors, Feng-Tso Sun, Cynthia Kuo, Heng-Tze Cheng, Senaka Buthpitiya, Patricia Collins, Martin Griss

Martin L Griss

"Continuous stress monitoring may help users better understand their stress patterns and provide physicians with more reliable data for interventions. Previously, studies on mental stress detection were limited to a laboratory environment where participants generally rested in a sedentary position. However, it is impractical to exclude the effects of physical activity while developing a pervasive stress monitoring application for everyday use. The physiological responses caused by mental stress can be masked by variations due to physical activity. We present an activity-aware mental stress detection scheme. Electrocardiogram (ECG), galvanic skin response (GSR), and accelerometer data were gathered from 20 participants across …


Control System Performance And Efficiency For A Mid-Depth Lagrangian Profiling Float, B. Mcgilvray, C. Roman May 2010

Control System Performance And Efficiency For A Mid-Depth Lagrangian Profiling Float, B. Mcgilvray, C. Roman

Christopher N. Roman

This paper presents the development of a new mid-depth Lagrangian profiling float with a primary emphasis on the control system performance and efficiency. While deep water floats have demonstrated much success in open ocean environments, many are not suited for the additional challenges associated with coastal regions. To study these regions, which are often subject to varying bathymetry within the operating range and higher variations in water density, a more advanced system is required. This new design utilizes pressure and altitude feedback to drive a high volume auto-ballasting system (ABS). The main operating modes of this float include step inputs …