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Full-Text Articles in Computer Engineering
Floating-Gate Devices: They Are Not Just For Digital Memories Anymore, Paul Hasler, Bradley Minch, Chris Diorio
Floating-Gate Devices: They Are Not Just For Digital Memories Anymore, Paul Hasler, Bradley Minch, Chris Diorio
Bradley Minch
Since the first reported floating-gate structure in 1967, floating-gate transistors have been used widely to store digital information for long periods in structures such as EPROMs and EEPROMs. Recently floating-gate devices have found applications as analog memories, analog and digital circuit elements, and adaptive processing elements. Floating-gate devices have found commerical applications, e.g. ISD, for long-term non-volatile information storage devices for analog applications. The focus of floating-gate devices has been towards fabrication in standard CMOS processes, as opposed to the specialized processes for fabricating digital non-volatile memories. Floating-gate circuits can be designed at any or all of three levels: analog …
A Floating-Gate Technology For Digital Cmos Processes, Bradley Minch, Paul Hasler
A Floating-Gate Technology For Digital Cmos Processes, Bradley Minch, Paul Hasler
Bradley Minch
We discuss the possibility of developing high-quality floating-gate memories and circuits in digital CMOS technologies that have only one layer of polysilicon. Here, the primary concern is whether or not we can get adequate control-gate linearity from MOS capacitors. We employ two experimental procedures to address this issue and find acceptable floating-gate circuit behaviour with MOS capacitors. First, we simultaneously characterize an MOS capacitor and a linear capacitor; the experimental data show that MOS capacitors behave similarly to linear capacitors over a finite, but usable range. Second, we characterize two typical floating-gateMOS circuit primitives, a floating-gate amplifier and a multiple-input …
Roach: An Autonomous 2.4g Crawling Hexapod Robot, Aaron Hoover, Erik Steltz, Ronald Fearing
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
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
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
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
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
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
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
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
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
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.