129 research outputs found
Coarse Information Design
We study an information design problem with continuous state and discrete
signal space. We find that the designer's interim value function affects the
solution only through its curvature. There is a dual relation between the prior
distribution and the marginal value function. Under convex value functions, the
optimal information structure is interval-partitional. Moreover, in logconcave
environments, a center of scrutiny emerges and information becomes coarser for
states farther from it. We locate the scrutiny center and provide comparative
statics on information structure with respect to prior distributions and value
functions. The analysis can be extended to S-shaped value functions
FlexDelta: A flexure-based fully decoupled parallel positioning stage with long stroke
Decoupled parallel positioning stages with large stroke have been
desired in high-speed and precise positioning fields. However, currently such
stages are either short in stroke or unqualified in parasitic motion and
coupling rate. This paper proposes a novel flexure-based decoupled parallel
positioning stage (FlexDelta) and conducts its conceptual design,
modeling, and experimental study. Firstly, the working principle of FlexDelta
is introduced, followed by its mechanism design with flexure. Secondly, the
stiffness model of flexure is established via matrix-based Castigliano's second
theorem, and the influence of its lateral stiffness on the stiffness model of
FlexDelta is comprehensively investigated and then optimally designed. Finally,
experimental study was carried out based on the prototype fabricated. The
results reveal that the positioning stage features centimeter-stroke in three
axes, with coupling rate less than 0.53%, parasitic motion less than 1.72 mrad
over full range. And its natural frequencies are 20.8 Hz, 20.8 Hz, and 22.4 Hz
for , , and axis respectively. Multi-axis path tracking tests were
also carried out, which validates its dynamic performance with micrometer
error
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