PCM Development Plan

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PCM Development Plan
Milestone Date Software Goal Experimental Goal
4.1.2.1 Purchase DE 10/1/03 (11/1/03) Revised Estimate
4.1.2.3 Identification of initial PCM for development 10/1/03 (10/17/03) Revised Estimate Have PCM Development Plan Characterized stage 1 PCM
4.1.2.5 PCM design review 10/31/03 (11/7/03) Revised Estimate Stage 1 implemented in DE Characterized stages 2-4 Have experimental goals and plan in pace for gecko, roach, and robot feet.
4.1.2.7 PCM prototype v0.1 to be exercised by users 12/2/03 Stage 2 implemented Test facilities in place and operating.
4.1.2.10 PCM v1.0 2/2/04 Stage 3 implemented First batch of experimental results on various feet. Begin matching to Stage 3 parameters.
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Stage 1 - Simple Contact
Ry
Model Description Rigid foot when in contact,
free when not Contact is state driven Release
it time based
Rx
Model Complexity Only 1 PCM parameter Tr the
time of release Geometry is a simple sphere with
appropriate springs/dampers
Questions Model can answer Measure reaction
forces to evaluate leg trajectories and foot
compliance, How much does leg squeezing reduce
reaction forces? Is 2.5kg excessive? How much
do we gain/pay for changing mass? What leg
trajectories minimize adhesion forces? How much
adhesion will feet need to provide? And for how
long?
3
Stage 2 - Simple Contact with time/random effects
Ry lt Limit
Model Description Rigid foot when in contact,
free when not Contact is state driven with
random element Release it time based or load
based (including time-dependencies)
Rx lt Limit
Model Complexity 4 more PCM parameters Slip
force thresholds, time dependence, and chance
of finding/loosing a foothold Geometry is a
simple sphere with spring/dampers
Questions Model can answer Evaluate gait
strategies, foot-hold finding strategies, role of
redundancy, Determine if gait is too fast
(cant find a foot-hold) or too slow (begin to
slip), Evaluate how inhomogeneous surfaces
affect getting a foot-hold
4
Stage 3 - Non-trivial Geometry
Model Description Foot with multiple toes
(claws sticky pads) Toes with different
contact properties Compliance between toes
Claw
Pad
Model Complexity More PCM parameters Pad
friction model, claw adhesion model Geometry is
a set of simple shapes with spring/dampers
between
Questions Model can answer Foot Design
strategies How many toes? What arraignment? How
much compliance between toes? How many
claws/pads? We can begin to match experimental
data for claws, setae, prototype feet
5
Stage 4 - Non-trivial Geometry Contact
Model Description Foot with multiple toes
(claws sticky pads) Toes with different
contact properties Compliance between toes Time
dependent friction Statistical surface properties
Claw
Pad
Model Complexity More PCM parameters Pad
friction model, claw adhesion model Time
dependent friction, Surface properties, More
complex pad and claw models, velocity dependent
friction Geometry is a set of simple shapes
with spring/dampers between
Questions Model can answer Foot design for
finding holds on different surfaces Feed-forward
foot finding algorithms. We can better match
experimental data for claws, setae, prototype
feet