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Algorithms for Sensorless Manipulation Using a Vibrating Surface
, 2000
"... We describe a programmable apparatus that uses a vibrating surface for sensorless, nonprehensile manipulation, where parts are systematically positioned and oriented without sensor feedback or force closure. The idea is to generate and change the dynamic modes of a vibrating surface. Depending on th ..."
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Cited by 27 (11 self)
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We describe a programmable apparatus that uses a vibrating surface for sensorless, nonprehensile manipulation, where parts are systematically positioned and oriented without sensor feedback or force closure. The idea is to generate and change the dynamic modes of a vibrating surface. Depending on the node shapes of the surface, the position and orientation of the parts can be predicted and constrained. The vibrating surface creates a twodimensional force vector field. By chaining together sequences of force fields, the equilibrium states of a part in the field can be successively reduced to obtain a desired final state. We describe efficient polynomialtime algorithms that generate sequences of force fields for sensorless positioning and orienting of planar parts, and we show that these strategies are complete. Finally we consider parts feeders that can only implement a finite set of force fields. We show how to plan and execute strategies for these devices. We give numerical exampl...
Planar Microassembly by Parallel Actuation
 of MEMS Microrobots—Supplementary Video,” Dept. Comput. Sci
, 2008
"... Abstract—We present designs, theory, and results of fabrication and testing for a novel parallel microrobotic assembly scheme using stressengineered MEMS microrobots. The robots are 240−280 µm × 60 µm × 7−20 µm insizeandcanbecontrolled to dock compliantly together, forming planar structures several ..."
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Cited by 23 (4 self)
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Abstract—We present designs, theory, and results of fabrication and testing for a novel parallel microrobotic assembly scheme using stressengineered MEMS microrobots. The robots are 240−280 µm × 60 µm × 7−20 µm insizeandcanbecontrolled to dock compliantly together, forming planar structures several times this size. The devices are classified into species based on the design of their steering arm actuators, and the species are further classified as independent if they can be maneuvered independently using a single global control signal. In this paper, we show that microrobot species are independent if the two transition voltages of their steering arms, i.e., the voltages at which the arms are raised or lowered, form a unique pair. We present control algorithms that can be applied to groups of independent microrobot species to direct their motion from arbitrary nondeadlock configurations to desired planar microassemblies. We present designs and fabrication for four independent microrobot species, each with a unique transition voltage. The fabricated microrobots are used to demonstrate directed assembly of five types of planar structures from two classes of initial conditions. We demonstrate an average docking accuracy of 5 µm and use selfaligning compliant interaction between the microrobots to further align and stabilize the intermediate assemblies. The final assemblies match their target shapes on average 96%, by area. [20070233] Index Terms—Microactuators, microassembly, microelectromechanical systems (MEMS), microrobots, scratchdrive actuators.
Assembly and Disassembly of Magnetic Mobile MicroRobots towards 2D Reconfigurable MicroSystems
"... Abstract A primary challenge in the field of reconfigurable robotics is scaling down the size of individual robotic modules. We present a novel set of permanent magnet modules that are 900 µm × 900 µm × 270 µm in size, called MagµMods, for use in a reconfigurable microsystem. The module is actuate ..."
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Cited by 9 (5 self)
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Abstract A primary challenge in the field of reconfigurable robotics is scaling down the size of individual robotic modules. We present a novel set of permanent magnet modules that are 900 µm × 900 µm × 270 µm in size, called MagµMods, for use in a reconfigurable microsystem. The module is actuated by oscillating external magnetic fields less than 5 mT in strength, and is capable of locomoting on a 2D surface. Multiple modules can be controlled by using an electrostatic anchoring surface, which can selectively prevent specific modules from being driven by the external field while allowing others to move freely. We address the challenges of both assembling and disassembling two modules. Assembly is performed by bringing two modules sufficiently close that their magnetic attraction causes them to combine. Disassembly is performed by electrostatically anchoring one module to the surface, and applying magnetic forces or torques from external sources to separate the unanchored module. 1
On the Area Bisectors of a Polygon
, 1997
"... We consider the family of lines that arearea bisectors of a polygon (possibly with holes) in the plane. We say that two bisectors of a polygon P are combinatorially distinct if they induce different partitionings of the vertices of P . We derive an algebraic characterization of area bisectors. We th ..."
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Cited by 7 (5 self)
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We consider the family of lines that arearea bisectors of a polygon (possibly with holes) in the plane. We say that two bisectors of a polygon P are combinatorially distinct if they induce different partitionings of the vertices of P . We derive an algebraic characterization of area bisectors. We then show that there are simple polygons with n vertices that have # n 2 # combinatorially distinct area bisectors #matching the obvious upper bound#, and present an outputsensitive algorithm for computing an explicit representation of all the bisectors of a given polygon. Our study is motivated by the development of novel, flexible feeding devices for parts positioning and orienting. The question of determining all the bisectors of polygonal parts arises in connection with the development of efficient part positioning strategies when using these devices.
Algorithmic MEMS
, 1998
"... As improvements in fabrication technology for MEMS #microelectromechanical systems# increase the availability and diversity of these micromachines, engineers are de#ning a growing number of tasks to which they can be put. The idea of carrying out tasks using large coordinated systems of MEMS units m ..."
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Cited by 4 (0 self)
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As improvements in fabrication technology for MEMS #microelectromechanical systems# increase the availability and diversity of these micromachines, engineers are de#ning a growing number of tasks to which they can be put. The idea of carrying out tasks using large coordinated systems of MEMS units motivates the development of automated, algorithmic methods for designing and controlling these groups of devices. We report here on progress towards algorithmic MEMS, taking on the challenge of design, control, and programming of massivelyparallel arrays of microactuators. We report on these developments in this focused survey paper, based on the research results originally reported in our 1994 paper #24# and developed further in #19,20,26,21,17,18,24,12,14,15, 9#. We describe how arrays of MEMS devices can move and position tiny parts, suchasintegrated circuit chips, in #exible and predictable ways by oscillatory or ciliary action. The theory of programmable force #elds can model this acti...
Sliding Manipulation of Rigid Bodies on a Controlled 6DoF Plate
"... Abstract — We model the full dynamics of a rigid part in threepoint frictional sliding contact with a flat rigid 6degreeoffreedom plate. Given a periodic plate motion and the geometric, inertial, and frictional properties of the part, we define an asymptotic twist field mapping each part configur ..."
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Cited by 1 (0 self)
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Abstract — We model the full dynamics of a rigid part in threepoint frictional sliding contact with a flat rigid 6degreeoffreedom plate. Given a periodic plate motion and the geometric, inertial, and frictional properties of the part, we define an asymptotic twist field mapping each part configuration to a unique part twist (linear and angular velocity). Asymptotic twist vectors in the field approximate the part’s cycleaveraged twist at each configuration and are independent of time or the system’s initial state. Simulations and experiments show that the trajectory of the part’s configuration as it slides on the plate is well described by the field. With the ability to program arbitrary plate motions, part manipulation reduces to finding plate motions that generate asymptotic twist fields to accomplish desired tasks. Several simple fields useful for manipulation tasks (e.g., sensorless part alignment) are verified in simulation and experiment. For the special case of a rigid part with infinitesimal thickness, we show that the part’s cycleaveraged twist for any configuration asymptotically converges to a unique asymptotic twist vector. I.
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS 1 Planar Microassembly by Parallel Actuation
"... Abstract—We present designs, theory, and results of fabrication and testing for a novel parallel microrobotic assembly scheme using stressengineered MEMS microrobots. The robots are 240−280 µm × 60 µm × 7−20 µm insizeandcanbecontrolled to dock compliantly together, forming planar structures several ..."
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Abstract—We present designs, theory, and results of fabrication and testing for a novel parallel microrobotic assembly scheme using stressengineered MEMS microrobots. The robots are 240−280 µm × 60 µm × 7−20 µm insizeandcanbecontrolled to dock compliantly together, forming planar structures several times this size. The devices are classified into species based on the design of their steering arm actuators, and the species are further classified as independent if they can be maneuvered independently using a single global control signal. In this paper, we show that microrobot species are independent if the two transition voltages of their steering arms, i.e., the voltages at which the arms are raised or lowered, form a unique pair. We present control algorithms that can be applied to groups of independent microrobot species to direct their motion from arbitrary nondeadlock configurations to desired planar microassemblies. We present designs and fabrication for four independent microrobot species, each with a unique transition voltage. The fabricated microrobots are used to demonstrate directed assembly of five types of planar structures from two classes of initial conditions. We demonstrate an average docking accuracy of 5 µm and use selfaligning compliant interaction between the microrobots to further align and stabilize the intermediate assemblies. The final assemblies match their target shapes on average 96%, by area. [20070233] Index Terms—Microactuators, microassembly, microelectromechanical systems (MEMS), microrobots, scratchdrive actuators.
Discrete Comput Geom 22:269–285 (1999) Discrete & ComputationalGeometry © 1999 SpringerVerlag New York Inc. On the Area Bisectors of a Polygon⁄
"... Abstract. We consider the family of lines that are area bisectors of a polygon (possibly with holes) in the plane. We say that two bisectors of a polygon P are combinatorially distinct if they induce different partitionings of the vertices of P. We derive an algebraic characterization of area bisect ..."
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Abstract. We consider the family of lines that are area bisectors of a polygon (possibly with holes) in the plane. We say that two bisectors of a polygon P are combinatorially distinct if they induce different partitionings of the vertices of P. We derive an algebraic characterization of area bisectors. We then show that there are simple polygons with n vertices that have˜.n2 / combinatorially distinct area bisectors (matching the obvious upper bound), and present an outputsensitive algorithm for computing an explicit representation