1 DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT Virtual Human ( review )
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1DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Virtual Human
( review )
2DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Plan
Need
Human motion : influential factors Proof
Control scheme (functional architecture) Pb of stability Details
Test cases relevance
Reusability
Progress
3DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Need
VH in mock-up
Autonomous manikin
Interactive manikin
Other techniques
Autonomy
(nb of ddl automatically driven)
Nb ddl ctrl > nb ddl cde :
- automate : nb ddl cde automation
- take time : drive ddl one after another
- standard devices
mouse, trackball…
- PDM auto check
- persuasive
- heavy infrastructure
- not relevant
uses
[Ren04]
4DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Need
VH in mock-up
Autonomous manikin
Interactive manikin
Other techniques
Autonomy
(nb of ddl automatically driven)
- standard devices
mouse, trackball…
- PDM auto check
- persuasive
- heavy infrastructure
- not relevant
uses
Virtual cockpit
Helicopter maintenance
Test cases : Need :
- visibility- reaching- retarget control- balance control- use tools (grasping)- accessibility- collision- interaction (env.)- strength analysis- energy expenditure
[Ren04]
[Ren04]
5DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Plan
Need
Human motion : influential factors Proof
Control scheme (functional architecture) Pb of stability Details
Test cases relevance
Reusability
Progress
6DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Human motion : influential factors
Motion sources :
- reaching goals : effectors control
external (cartesian) potentials
Rem : concurrent tasks
tasks priority (decoupling)
- physical, biological constraints contact (collision / interaction)
joint limits
balance
unilateral constraints
- humans specificity attitude
energy expenditure control
internal (articular) potentials
7DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Human motion : influential factors
Motion sources :
- reaching goals : effectors control
external (cartesian) potentials
Rem : concurrent tasks
tasks priority (decoupling)
- physical, biological constraints contact (collision / interaction)
joint limits
balance
unilateral constraints
- humans specificity attitude
energy expenditure control
internal (articular) potentials
8DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Decoupling : why?
- effector’s position controlled
- internal potential not considered yet
- effector’s position controlled
- internal potential optimized without decoupling
First step Second step
9DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Human motion : influential factors
Motion sources :
- reaching goals : effectors control
external (cartesian) potentials
Rem : concurrent tasks
tasks priority (decoupling)
- physical, biological constraints contact (collision / interaction)
joint limits
balance
unilateral constraints
- humans specificity attitude
energy expenditure control
internal (articular) potentials
10DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Unilateral constraints : why?
joint limits : contact :
balance :
ex : retargeting of a giant’s mvt to a baby’
skeleton
11DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Human motion : influential factors
Motion sources :
- reaching goals : effectors control
external (cartesian) potentials
Rem : concurrent tasks
tasks priority (decoupling)
- physical, biological constraints contact (collision / interaction)
joint limits
balance
unilateral constraints
- humans specificity attitude
energy expenditure control
internal (articular) potentials
12DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Attitude : why?
3DSmax 7’s IK : no "attitude" management
13DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Plan
Need
Human motion : influential factors Proof
Control scheme (functional architecture) Pb of stability Details
Test cases relevance
Reusability
Progress
14DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
The system to be controlled
The manikin is seen as deformable skin which is controlled thanks to a skeleton.
Skeleton: polyarticulated arborescent kinematical chain
The skeleton is given a geometrical representation to allow collision tests
with environment
the lowest control-level is done through actuated joints
15DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Global control scheme
Control
Simulation
6D targets positions and
velocitiesavatar joint positions
rigid bodies positions
avatar joint torques virtual human
being animated in real time
real world actor’s movements
being observed through motion
capture
16DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Detailed control scheme (functional view)In
problems solved jointly
Robotic framework :
GVM (CEA) : simple control,
contact, limits…
Decoupling :- n targets priority
Method : dynamics
Attitude :- realism
Method : potential functions optimisation
Balance :- enforce mvt feasibility
Method : unilateral constraint (LCP)
Legend : : information flow
: I \ O ports
1st order dynamics
Interaction forces
dynamics
API : integrator
API : ulc solver
Out (visu 3D)
Projections :
- help (virtual guides)
- first step towards autonomy
passively projected6D marker
pos
manikin’ state
compensation torquetorque
contribution at each control
point
projected torque
contributions
manikin’s articular
configuration
attitude torque’s
contribution
6Dpos
Mo
tio
n c
ap
ture
Collision detection (searches Local Minimal Distance) : LMD++ (CEA)
17DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Key points : stability by passivity
Controller >0
RT simulation >0
+
-
Input device:MocapHaptic
Etc.
Both blocks are discrete and non linear
The controller & the Real Time simulation should be passive to ensure stability
passivity :
integration scheme
passivity :
each control block
Passivity: control paradigm ensuring stability. Useful in complex systems, because it allows to decouple the passivity (thus stability) of the whole system into the passivity of each of the components of the system
18DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Detailed control scheme (functional view)In
problems solved jointly
Decoupling :- n targets priority
Method : dynamics
Attitude :- realism
Method : potential functions optimisation
Balance :- enforce mvt feasibility
Method : unilateral constraint (LCP)
Legend : : information flow
: I \ O ports
API : integrator
API : ulc solver
Out (visu 3D)
Projections :
- help (virtual guides)
- first step towards autonomy
passively projected6D marker
pos
manikin’ state
compensation torquetorque
contribution at each control
point
projected torque
contributions
manikin’s articular
configuration
attitude torque’s
contribution
6Dpos
Mo
tio
n c
ap
ture
Robotic framework :
GVM (CEA) : simple control,
contact, limits…
1st order dynamics
Interaction forces
dynamics
Collision detection (searches Local Minimal Distance) : LMD++ (CEA)
19DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
First order dynamics & control (1/2)
usual 2nd order dynamics:
passage en dynamique du 1er ordre mass is neglected joints are separated into position controlled joints, and force
controlled joints
integration is done through additional joint damping
qGqqqCqqM ,
p
f
q
fartqB
fartqB
couples articulaires
NOTE : First order dynamics and external control are handled by GVM (product developped by CEA\LIST)
20DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
PD cartesian control has a component used for internal control, and a
component which is a PD corrector to achieve external control
developping this expression we obtain the evolution equation in joint space
in previous equation, the inverse can be calculated under given conditions (not restrictive)
First order dynamics & control (1/2)
fC
farti
iidiiidiTiff qBvvBxxKJC
fi
iidiipipiTif
iifi
Tifartf CxxKvqJBJJBJBq
1
system’s jacobien control gains
NOTE : First order dynamics and external control are handled by GVM (product developped by CEA\LIST)
21DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Detailed control scheme (functional view)In
problems solved jointly
Decoupling :- n targets priority
Method : dynamics
Attitude :- realism
Method : potential functions optimisation
Balance :- enforce mvt feasibility
Method : unilateral constraint (LCP)
Legend : : information flow
: I \ O ports
API : integrator
API : ulc solver
Out (visu 3D)
Projections :
- help (virtual guides)
- first step towards autonomy
passively projected6D marker
pos
manikin’ state
compensation torquetorque
contribution at each control
point
projected torque
contributions
manikin’s articular
configuration
attitude torque’s
contribution
6Dpos
Mo
tio
n c
ap
ture
Robotic framework :
GVM (CEA) : simple control,
contact, limits…
1st order dynamics
Interaction forces
dynamics
Collision detection (searches Local Minimal Distance) : LMD++ (CEA)
22DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Decoupling (prioritization) (1/3)
State of the art : kinematics : multi-tasks dynamics :
• 2 tasks passive
• multi-tasks non passive
Innovation : 1st order dynamics multi-tasks passive decoupling (GVM) 2nd order dynamics multi-tasks passive decoupling
Tested approaches : multi-tasks kinematics : (OK), no interaction dismissed
Done, to do : internal potential ok, external potentials ? implement algorithm, test
23DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Problem
Mathematical view (without prioritization)
Decoupling (prioritization) (2/3)
without prioritization:
in case of target conflicts no target is reached
with prioritization:
in case of target conflicts, targets priorities are enforced
21
task 1task 2 task 2
task 1
influence (torque) of task 2 can disturb task 1
24DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Solution project task 2’s influence such that it does not disturb higher
priority tasks
this control can be extended to n tasks
Decoupling (prioritization) (3/3)
211 projection to avoid disturbing task 1
25DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Control scheme (functional p.o.v.)In
problems solved jointly
Decoupling :- n targets priority
Method : dynamics
Attitude :- realism
Method : potential functions optimisation
Balance :- enforce mvt feasibility
Method : unilateral constraint (LCP)
Legend : : information flow
: I \ O ports
API : integrator
API : ulc solver
Out (visu 3D)
Projections :
- help (virtual guides)
- first step towards autonomy
passively projected6D marker
pos
manikin’ state
compensation torquetorque
contribution at each control
point
projected torque
contributions
manikin’s articular
configuration
attitude torque’s
contribution
6Dpos
Mo
tio
n c
ap
ture
Robotic framework :
GVM (CEA) : simple control,
contact, limits…
1st order dynamics
Interaction forces
dynamics
Collision detection (searches Local Minimal Distance) : LMD++ (CEA)
26DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Attitude (1/3)
Principal : optimize potential function caracterizing a "human attitude"
State of the art : potential functions empirical, not generic…
Innovation : ?
Done, to do : implement, and test
Test : ideally : compare positions of limbs (VH / n performers)
• difficult, interesting ? : empirically (human brain outstanding!)
27DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Problem because of its redundant nature,a virtual human is still under-
constrained after solving for the cartesian constraints thus several configurations allow to enforce cartesian constraints solving for the internal problem (or attitude) allows to choose the
configuration that best represent a human posture
Mathematical view solving for cartesian control (dimensional problem) :
the relation J is not invertible : the system has an infinite number of solutions (such systems are called redundant)
Attitude (2/3)
=q
Jx
joint parameterseffector’s position
28DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Solution find one solution q1 to the cartesian control (thanks to the moore-
penrose inverse) :
add constraints to the systems (other tasks), to fully constrain the problem
Attitude (3/3)
11
min qJxq
21 qqq
cartesian tasks contributioninternal tasks (attitude) contribution (must
not disturb cartesian control)
total joint parameters increment at current time-step
29DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Control scheme (functional p.o.v.)In
problems solved jointly
Decoupling :- n targets priority
Method : dynamics
Attitude :- realism
Method : potential functions optimisation
Balance :- enforce mvt feasibility
Method : unilateral constraint (LCP)
Legend : : information flow
: I \ O ports
API : integrator
API : ulc solver
Out (visu 3D)
Projections :
- help (virtual guides)
- first step towards autonomy
passively projected6D marker
pos
manikin’ state
compensation torquetorque
contribution at each control
point
projected torque
contributions
manikin’s articular
configuration
attitude torque’s
contribution
6Dpos
Mo
tio
n c
ap
ture
Robotic framework :
GVM (CEA) : simple control,
contact, limits…
1st order dynamics
Interaction forces
dynamics
Collision detection (searches Local Minimal Distance) : LMD++ (CEA)
30DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Balance (1/3)
State of the art : static equilibrium of a posture caracterized
• critical for test cases
Innovation : new approach (well posed) suits the global VH control scheme
Numerical methods : unilateral constraint thanks to a LCP solver (Lemke)
Done, to do : being implemented, and tested
COM
31DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Problem
Mathematical view
Balance (2/3)
real "giant" actor
virtual "dwarf" avatar
targets constrained(desired position
specified by actor)
when movements of a "giant" actor are retargeted on a "dwarf" avatar, the dwarf may
not be balanced anymore
this leads to unfeasible movements of the avatar
k
kkcom
f
zpfzx
force at contact k
lever arm of contact kCOM’s position
vertical vector
Interpretation:
the projection of the COM on the ground must lie in the "support polygon"
32DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Solution
Limitation the mathematical view shown here is rather restrictive (only
handles a sub-set of the problem) : contacts must lie on the same plane
Balance (3/3)
both feetactual support polygon
elliptical approximation of
the support polygon
projection of the COM on the ground
approximation of the support polygon by an ellipse
Enforce
22dxxP
Qccom (which states that the projection of the COM on
the ground must lie in the "support polygon")
while solving the evolution equation.
NOTE : we solved the problem on an elliptical approximation of the support polygon, it could be easily extended to other shapes…
33DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Control scheme (functional p.o.v.)In
problems solved jointly
Decoupling :- n targets priority
Method : dynamics
Attitude :- realism
Method : potential functions optimisation
Balance :- enforce mvt feasibility
Method : unilateral constraint (LCP)
Legend : : information flow
: I \ O ports
API : integrator
API : ulc solver
Out (visu 3D)
Projections :
- help (virtual guides)
- first step towards autonomy
passively projected6D marker
pos
manikin’ state
compensation torquetorque
contribution at each control
point
projected torque
contributions
manikin’s articular
configuration
attitude torque’s
contribution
6Dpos
Mo
tio
n c
ap
ture
Robotic framework :
GVM (CEA) : simple control,
contact, limits…
1st order dynamics
Interaction forces
dynamics
Collision detection (searches Local Minimal Distance) : LMD++ (CEA)
34DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Projections : semi-autonomous mode (1/3)
Principal : guide the manikin through projections
State of the art : matrix projections «as is» : passivity intrinsically passive projections through virtual mechanisms
Innovation : new to virtual humans control
Done, to do : implemented, tested, being published
Test : Virtual human performing a precision task
35DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Problem because of the lack of haptic sensations, it can be difficult for the
the immersed actor to achieve some movements the most intuitive solution to implement these guides is to project
targets’ positions : but projections are unsafe as for passivity
Solution build passive projections thanks to mechanical analogies also
called virtual mechanisms (real world mechanisms being always passive, we can emulate them)
Projections : semi-autonomous mode (2/3)
36DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Solution
Projections : semi-autonomous mode (3/3)
virtual mechanism:
guides movements
wall to be drilled
constraint coupling
target, and task space control
control point
future hole position
virtual human holding a drill
virtual mechanism (in red) helping the manikin aligning a drill on the futur hole’s position
37DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Plan
Need
Human motion : influential factors Proof
Control scheme (functional architecture) Pb of stability Details
Test cases relevance
Reusability
Progress
38DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Test cases relevance (1 / 2)
Virtual cockpit test
Highlighted points :
- multi-targets decoupling
- attitude
Decoupling :- n targets priority
Method : dynamics
Attitude :- realism
Method : potential functions optimisation
manikin’s articular
configuration
attitude torque’s
contribution
39DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Test cases relevance (2 / 2)
Helicopter (ladder climbing) test
Balance :- enforce mvt feasibility
Method : unilateral constraint (LCP)
Highlighted points :
- multi-targets decoupling
- attitude
- balance control
Decoupling :- n targets priority
Method : dynamics
Attitude :- realism
Method : potential functions optimisation
manikin’s articular
configuration
attitude torque’s
contribution
40DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Plan
Need
Human motion : influential factors Proof
Control scheme (functional architecture) Pb of stability Details
Test cases relevance
Reusability
Progress
41DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Reusability
work direction driven by test cases
useful work… work
test cases
Code (functions mapping)
Methods
Architecture
Specifications (thesis)
42DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Plan
Need
Human motion : influential factors Proof
Control scheme (functional architecture) Pb of stability Details
Test cases relevance
Reusability
Progress
43DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Progress report
Interactive manikin :
Decoupling :
Balance :
Attitude :
Test cases :
Thesis editing :
Todaytook for granted to be done
publication Pacific Graphics
(fin avril 05)
Legend : : implementation
: theory
: tests
: publication
trainee
publication Virtual Concept
(fin mars 05)publication IROS
(début février 05)
publication SCSC
(fin février 05)
publication SCA
(mi avril 05)
Reviews :
avec IRCCyN
début mai 05:
Démonstrateurs niveau indus. pour Bourget?
avec IRCCyN
fin juin 05:
préparation rédaction thèse
44DTSI /COGNITICS, ROBOTICS AND INTERACTION UNIT
Demo