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Refactor event key handling and add new cable-driven Cosserat beam scene

- Updated key event handling in geo_cable_driven_cosserat_beam.py to use
string-based key comparison for + and - keys.
- Fixed minor formatting issue by adding missing comma in
RestShapeSpringsForceField.
- Added new scene file geo_cosserat_cable_driven_cosserat_beam.py for
simulating cable-driven Cosserat beams, with detailed parameter
definitions for beam geometry and physics.
- Introduced PullingCosseratCable controller in
pulling_cosserat_cable.py to handle cable pulling mechanics.
- Replaced BeamPhysicsParameters with BeamPhysicsParametersNoInertia in
tuto_5.py for more specific physical simulations.
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adagolodjo committed Oct 9, 2024
1 parent 0752b10 commit a5e9503
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6 changes: 3 additions & 3 deletions tutorial/tuto_scenes/geo_cable_driven_cosserat_beam.py
Original file line number Diff line number Diff line change
Expand Up @@ -45,10 +45,10 @@ def __init__(self, *args, **kwargs):

def onKeypressedEvent(self, event):
displacement = self.cable.CableConstraint.value[0]
if event["key"] == Key.plus:
if event["key"] == "+":
displacement += 1.

elif event["key"] == Key.minus:
elif event["key"] == "-":
displacement -= 1.
if displacement < 0:
displacement = 0
Expand All @@ -68,7 +68,7 @@ def createScene(root_node):
"RestShapeSpringsForceField",
name="spring",
stiffness=1e8,
angularStiffness=1.0e8
angularStiffness=1.0e8,
external_points=0,
points=0,
template="Rigid3d"
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129 changes: 129 additions & 0 deletions tutorial/tuto_scenes/geo_cosserat_cable_driven_cosserat_beam.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,129 @@
# -*- coding: utf-8 -*-
"""
Cosserat class in SofaPython3.
"""

__authors__ = "adagolodjo"
__contact__ = "[email protected]"
__version__ = "1.0.0"
__copyright__ = "(c) 2021,Inria"
__date__ = "October, 09 2024"

from useful.header import addHeader, addSolverNode
from useful.params import Parameters
from useful.params import BeamPhysicsParametersNoInertia, BeamGeometryParameters, \
ContactParameters
from cosserat.CosseratBase import CosseratBase
import Sofa

# Define the beam parameters
beam_length = 1.
geoParams = BeamGeometryParameters(beam_length=beam_length, nb_section=12, nb_frames=12, build_collision_model=0)
physicsParams = BeamPhysicsParametersNoInertia(beam_mass=0.03, young_modulus=1.0e5, poisson_ratio=0.4, beam_radius=0.04,
beam_length=beam_length)
contactParams = ContactParameters()
Params = Parameters(beam_geo_params=geoParams, beam_physics_params=physicsParams, contact_params=contactParams)

# Define Cable parameters
cable_length = 1.2
cable_geo_params = BeamGeometryParameters(beam_length=cable_length, nb_section=16, nb_frames=16,
build_collision_model=1)
cable_physics_params = BeamPhysicsParametersNoInertia(beam_mass=0.03, young_modulus=1.0e7, poisson_ratio=0.4,
beam_radius=0.005, beam_length=cable_length)
cable_params = Parameters(beam_geo_params=cable_geo_params, beam_physics_params=cable_physics_params)

def add_mecha_points_with_skinng_maps(node_name, parent_node, positions, _show=True):
node = parent_node.addChild(node_name)
meca_node = node.addObject('MechanicalObject', position=positions, template="Vec3d", name=node_name+"_mo")
node.addObject('SkinningMapping', nbRef="1", name="skinning_mapping")
return meca_node


def show_mecha_visual(node, show=True):
node.showObject = show
node.showIndices = show


class CableController(Sofa.Core.Controller):
def __init__(self, *args, **kwargs):
Sofa.Core.Controller.__init__(self, args, kwargs)
self.cable = args[0]
self.move = True

def onAnimateEndEvent(self, event):
if self.move:
self.pull_cable()

def pull_cable(self):
with self.cable.rest_position.writeable() as pos:
pos[0][0] -= 0.01

def onKeypressedEvent(self, event):
if event["key"] == "+":
self.move = True
elif event["key"] == "-":
self.move -= False


def createScene(root_node):

addHeader(root_node, is_constrained=1, is_contact=1, contact_params=Params)
root_node.gravity = [0, -9.81, 0.]
solver_node = addSolverNode(root_node, name="solver_node")

solver_node.addObject('GenericConstraintCorrection')
# create cosserat Beam
beam = solver_node.addChild(CosseratBase(parent=solver_node, beam_params=Params))
# Attach beam base using a spring force field
beam.rigidBaseNode.addObject(
"RestShapeSpringsForceField",
name="spring",
stiffness=1e8,
angularStiffness=1.0e8,
external_points=0,
points=0,
template="Rigid3d"
)

# add points inside the beam
frame_node = beam.rigidBaseNode.cosseratInSofaFrameNode
sliding_position = [[0, 0, 0.02], [0.2, 0, 0.02], [0.4, 0, 0.02], [0.6, 0, 0.02], [0.8, 0, 0.02], [1, 0, 0.02]]
sliding_mo = add_mecha_points_with_skinng_maps(node_name='mapped_poind', parent_node=frame_node, positions=sliding_position)

# Add cable to the scene
cable_solver = addSolverNode(root_node, name="cable_solver")
cable_node = cable_solver.addChild(CosseratBase(parent=cable_solver, translation=[-0.2, 0, 0.02],
beam_params=cable_params, name="cable"))
cable_solver.addObject('GenericConstraintCorrection')
cable_frames_node = cable_node.cosseratFrame

# This creates a new node in the scene. This node is appended to the finger's node.
cable_state_node = cable_frames_node.addChild('cable_state_node')

# This creates a MechanicalObject, a component holding the degree of freedom of our
# mechanical modelling. In the case of a cable it is a set of positions specifying
# the points where the cable is passing by.
cable_state = cable_state_node.addObject('MechanicalObject', name="cablePos",
position=cable_node.frames3D)
show_mecha_visual(cable_state, show=True)
cable_state_node.addObject('IdentityMapping')

""" These positions are in fact the distance between the 3D points mapped inside the Beam and the cable points"""
distance_node = cable_state_node.addChild('distance_node')
beam.cosseratFrame.addChild(distance_node)

distance = distance_node.addObject('MechanicalObject', template='Vec3d', position=sliding_position,
name="distancePointsMO", showObject='1', showObjectScale='1')

"""The controller of the cable is added to the scene"""
# cable_state_node.addObject(CableController(cable_node.rigidBaseNode.RigidBaseMO))

inputCableMO = cable_state.getLinkPath()
sliding_points = sliding_mo.getLinkPath()
outputPointMO = distance.getLinkPath()
""" This constraint is used to compute the distance between the cable and the fem points"""
distance_node.addObject('QPSlidingConstraint', name="QPConstraint")
distance_node.addObject('DifferenceMultiMapping', name="pointsMulti", input1=sliding_points, indices="5",
input2=inputCableMO, output=outputPointMO, direction="@../../FramesMO.position")

return root_node
7 changes: 7 additions & 0 deletions tutorial/tuto_scenes/git_msg.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
Refactor event key handling and add new cable-driven Cosserat beam scene

- Updated key event handling in geo_cable_driven_cosserat_beam.py to use string-based key comparison for + and - keys.
- Fixed minor formatting issue by adding missing comma in RestShapeSpringsForceField.
- Added new scene file geo_cosserat_cable_driven_cosserat_beam.py for simulating cable-driven Cosserat beams, with detailed parameter definitions for beam geometry and physics.
- Introduced PullingCosseratCable controller in pulling_cosserat_cable.py to handle cable pulling mechanics.
- Replaced BeamPhysicsParameters with BeamPhysicsParametersNoInertia in tuto_5.py for more specific physical simulations.
46 changes: 46 additions & 0 deletions tutorial/tuto_scenes/pulling_cosserat_cable.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,46 @@
import Sofa.Core
from splib3.numerics import Quat


class PullingCosseratCable(Sofa.Core.Controller):
def __init__(self, *args, **kwargs):
Sofa.Core.Controller.__init__(self, *args, **kwargs)
self.cable = kwargs['frame_node'].FramesMO
self.tip_controller = kwargs['tip_controller']

def onAnimateEndEvent(self, event):
pass

def pull_cable(self):
with self.cable.restPosition.writeable() as pos:
pos[0][0] -= self.rate

def compute_orthogonal_force(self):
position = self.frames.position[self.size] # get the last rigid of the cosserat frame
orientation = Quat(position[3], position[4], position[5], position[6]) # get the orientation
# Calculate the direction of the force in order to remain orthogonal to the x axis of the last frame of the beam.
with self.forceNode.forces.writeable() as force:
vec = orientation.rotate([0., self.forceCoeff * 5.e-2, 0.])
vec.normalize()
# print(f' The new vec is : {vec}')
for count in range(3):
force[0][count] = vec[count]

def rotate_force(self):
if self.forceCoeff <= 100. * pi:
with self.tip_controller.position.writeable() as position:
last_frame = self.frames.position[self.size]
vec = Quat(last_frame[3], last_frame[4], last_frame[5], last_frame[6]) # get the orientation

vec.rotateFromEuler([self.theta, 0., 0.]) # apply rotation arround x-axis
vec.normalize()
for i, v in enumerate(vec):
position[0][i + 3] = v

def onKeypressedEvent(self, event):
key = event['key']
if key == "+":
self.applyForce = True
elif key == "-":
self.applyForce = False

6 changes: 3 additions & 3 deletions tutorial/tuto_scenes/tuto_5.py
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@
__date__ = "October, 26 2021"

from useful.header import addHeader, addSolverNode, addVisual
from useful.params import BeamPhysicsParameters, BeamGeometryParameters, SimulationParameters
from useful.params import BeamPhysicsParametersNoInertia , BeamGeometryParameters, SimulationParameters
from useful.params import Parameters
from cosserat.CosseratBase import CosseratBase
from math import sqrt
Expand All @@ -27,7 +27,7 @@

geoParams = BeamGeometryParameters(init_pos=[0., 0., 0.], beamLength=81., showFramesObject=1,
nbSection=12, nbFrames=32, buildCollisionModel=0)
physicsParams = BeamPhysicsParameters(beamMass=1., youngModulus=5.e6, poissonRatio=0.4, beamRadius=0.5,
physicsParams = BeamPhysicsParametersNoInertia(beamMass=1., youngModulus=5.e6, poissonRatio=0.4, beamRadius=0.5,
beamLength=30)

simuParams = SimulationParameters()
Expand Down Expand Up @@ -119,7 +119,7 @@ def createScene(root_node):
# This creates a new node in the scene. This node is appended to the finger's node.
cable_state_node = cosserat_frames_node.addChild('cable_state_node')

# This creates a MechanicalObject, a componant holding the degree of freedom of our
# This creates a MechanicalObject, a componante holding the degree of freedom of our
# mechanical modelling. In the case of a cable it is a set of positions specifying
# the points where the cable is passing by.
cable_state = cable_state_node.addObject('MechanicalObject', name="cablePos",
Expand Down

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