{"id":715,"date":"2016-10-03T13:19:13","date_gmt":"2016-10-03T13:19:13","guid":{"rendered":"http:\/\/project.inria.fr\/softrobot\/?page_id=715"},"modified":"2017-07-28T08:40:13","modified_gmt":"2017-07-28T08:40:13","slug":"forcepointactuator","status":"publish","type":"page","link":"https:\/\/project.inria.fr\/softrobot\/forcepointactuator\/","title":{"rendered":"ForcePointActuator"},"content":{"rendered":"

General description<\/strong><\/h1>\n

This component is used to solve an effector constraint by applying a force on a given point of a model.<\/p>\n

\"\"

Simulation of two colliding soft bodies. We control the position (white sphere) of a point of the red body by applying a force on the brown one.<\/p><\/div>\n

Methods description<\/strong><\/h1>\n

Requirement<\/strong>:\u00a0Real time inverse simulation method<\/a><\/p>\n

Method<\/strong><\/p>\n

Here, the constraint matrix J will contain the given direction of the force in the rows corresponding to the given point of the model, and\u00a0\u03bb will represent the intensity of the applied force.<\/p>\n

How to use the component<\/strong><\/h1>\n

To learn how to create a SOFA scene, please refer to the tutorial provided by the SOFA Modeler or this<\/a>\u00a0documentation.
\nAn example is provided in the “examples” directory of the plugin. Let’s consider this deformable object:<\/p>\n

skin = rootNode.createChild('skin')\r\nskin.createObject('EulerImplicit', name='odesolver')\r\nskin.createObject('SparseLDLSolver', name='preconditioner')\r\n\r\nskin.createObject('MeshVTKLoader', name='loader', filename=path+'skin.vtk')\r\nskin.createObject('TetrahedronSetTopologyContainer', src='@loader', name='container')\r\nskin.createObject('TetrahedronSetTopologyModifier')\r\nskin.createObject('TetrahedronSetTopologyAlgorithms')\r\nskin.createObject('TetrahedronSetGeometryAlgorithms')\r\n\r\nskin.createObject('MechanicalObject', name='tetras', showIndices='false', showIndicesScale='4e-5')\r\nskin.createObject('UniformMass', totalmass='0.03')\r\nskin.createObject('TetrahedronFEMForceField', name='FEM', method='large', poissonRatio='0.3', youngModulus='180', drawAsEdges=\"1\")\r\n...\r\nskin.createObject('LinearSolverConstraintCorrection', solverName='preconditioner')\r\n<\/pre>\n
You can define the positions on which you want to apply the force and map these position to the deformable object by creating a child node and using a “Mapping” component:<\/p>\n
pointForce = skin.createChild('pointForce')\r\npointForce.createObject('MechanicalObject', position=\"72 68 -2 70 70 2 70 70 0\")\r\npointForce.createObject('ForcePointActuator', triangles='@topo.triangles', direction=\"-1 -1 0\", indices=\"0 1 2\", maxForce=\"90\", minForce=\"0\", maxForceVariation=\"5\")\r\npointForce.createObject('BarycentricMapping', name='mapping', mapForces='false', mapMasses='false')<\/pre>\n
The direction of the force is specified by the user. By using an “Effector” component and the “QPInverseProblemSolver” you can solve the inverse problem of finding the right force to apply to solve the effector target.<\/p>\n
Data field<\/strong><\/h1>\n
Here are described the data fields corresponding to this particular component.<\/p>\n
Input data<\/span><\/strong><\/h2>\n
indices<\/strong>\u00a0:\u00a0Index of the point of the model on which we want to apply the force.<\/p>\n
maxForce<\/strong>\u00a0\/minForce<\/strong>: Correspond to the constrainst \u03bbmin<\/sub>\u00a0\u2264 \u03bb\u00a0\u2264\u00a0\u03bbmax<\/sub> where \u03bb represents the force.\u00a0If no values are set by the user, no constraint on \u03bb\u00a0will be considered. Note that the force is constrained to be positive.<\/p>\n
maxForceVariation: <\/b>Maximum variation of the force\u00a0allowed. If not set, no max variation will be concidered.<\/p>\n
direction<\/strong>:\u00a0Direction of the force we want to apply.<\/p>\n
Output data<\/span><\/strong><\/h2>\n
displacement : <\/strong>Displacement achieved at the end of the time step compared to initial state.\u00a0\u03b4\u00a0= Waa<\/sub>\u03bb +\u00a0\u03b4free<\/sup><\/p>\n
force <\/strong>: The force\u00a0\u03bb\u00a0applied at the end of the time step.<\/p>\n","protected":false},"excerpt":{"rendered":"
General description This component is used to solve an effector constraint by applying a force on a given point of a model. Methods description Requirement:\u00a0Real time inverse simulation method Method Here, the constraint matrix J will contain the given direction of the force in the rows corresponding to the given\u2026<\/p>\n
 Continue reading<\/span><\/i><\/a> <\/p>\n","protected":false},"author":850,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-715","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/project.inria.fr\/softrobot\/wp-json\/wp\/v2\/pages\/715","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/project.inria.fr\/softrobot\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/project.inria.fr\/softrobot\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/project.inria.fr\/softrobot\/wp-json\/wp\/v2\/users\/850"}],"replies":[{"embeddable":true,"href":"https:\/\/project.inria.fr\/softrobot\/wp-json\/wp\/v2\/comments?post=715"}],"version-history":[{"count":6,"href":"https:\/\/project.inria.fr\/softrobot\/wp-json\/wp\/v2\/pages\/715\/revisions"}],"predecessor-version":[{"id":827,"href":"https:\/\/project.inria.fr\/softrobot\/wp-json\/wp\/v2\/pages\/715\/revisions\/827"}],"wp:attachment":[{"href":"https:\/\/project.inria.fr\/softrobot\/wp-json\/wp\/v2\/media?parent=715"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}