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We present a new upper-limb anthropomorphic dexterous telemanipulation system, the Dexterity Testbed Nexus(DexNex). DexNex is teleoperated by a human user in theOperator Station who controls the Avatar Station to complete temanipulation tasks. The Avatar replicates the upper limbs of a human and is statically mounted to the workspace. Three benchmarking tasks were used: box & blocks, the MinnesotaTurning Test revised form (MTTrf), and a table setting task.Subjects completed the tasks with their natural bodies to provide normative data. Subjects then attempted the same tasks with haptic feedback enabled or disabled. The utility of haptics was computed for four metrics. Haptic feedback improved performance for three of the four metrics (26% increase in Box& Blocks score, 12% increased Table Setting success rate, and 1.3x faster time per success in Table Setting). 

In this article, we characterize the passivity of a class of haptic systems modeled as a simple sampled-data system. We guarantee passivity by ensuring that there is sufficient damping in the haptic interface. Previous work established a necessary and sufficient bound on damping, but the corresponding mathematical expressions were complicated, and the derivation was not completely rigorous. After providing a rigorous proof, we derive a more tractable expression. Using this improved expression, we establish passivity conditions for several classes of transfer functions representing virtual environments, including some special cases with time delay. The original results assumed that the operator can be modeled by a passive but otherwise arbitrary transfer function. This assumption is weakened to allow the operator model to have a shortage of passivity. This requires only a slight modification of the passivity bound. 

We present PixeLite, a novel haptic device that produces distributed lateral forces on the fingerpad. PixeLite is 0.15 mm thick, weighs 1.00 g, and consists of a 4×4 array of electroadhesive brakes (“pucks”) that are each 1.5 mm in diameter and spaced 2.5 mm apart. The array is worn on the fingertip and slid across an electrically grounded countersurface. It can produce perceivable excitation up to 500 Hz. When a puck is activated at 150 V at 5 Hz, friction variation against the countersurface causes displacements of 627 ± 59 μ m. The displacement amplitude decreases as frequency increases, and at 150 Hz is 47 ± 6 μ m. The stiffness of the finger, however, causes a substantial amount of mechanical puck-to-puck coupling, which limits the ability of the array to create spatially localized and distributed effects. A first psychophysical experiment showed that PixeLite's sensations can be localized to an area of about 30% of the total array area. A second experiment, however, showed that exciting neighboring pucks out of phase with one another in a checkerboard pattern did not generate perceived relative motion. Instead, mechanical coupling dominates the motion, resulting in a single frequency felt by the bulk of the finger.