visual3d:documentation:kinematics_and_kinetics:external_forces:force_structures
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| Both sides previous revisionPrevious revisionNext revision | Previous revision | ||
| visual3d:documentation:kinematics_and_kinetics:external_forces:force_structures [2024/07/12 14:00] – created sgranger | visual3d:documentation:kinematics_and_kinetics:external_forces:force_structures [2024/07/17 15:45] (current) – created sgranger | ||
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| - | ====== | + | ====== |
| Force Structures were conceived as a mechanism for combining force platform data (e.g. treating several contiguous platforms as a single platform), and for accommodating structures that are attached to the force platform as a super-structure such as the stairs manufactured by AMTI. | Force Structures were conceived as a mechanism for combining force platform data (e.g. treating several contiguous platforms as a single platform), and for accommodating structures that are attached to the force platform as a super-structure such as the stairs manufactured by AMTI. | ||
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| For a surface (e.g. a step) placed on top of the force platform, the COP is translated along the Force Vector to the new surface. (e.g. the intersection of the force with the new surface). | For a surface (e.g. a step) placed on top of the force platform, the COP is translated along the Force Vector to the new surface. (e.g. the intersection of the force with the new surface). | ||
| - | {{Force_Structure.jpg}} | + | {{:Force_Structure.jpg}} |
| This figure shows a picture of an oblique force applied to a step. This figure shows one type of force platform, but the concept applies equally to all platforms. | This figure shows a picture of an oblique force applied to a step. This figure shows one type of force platform, but the concept applies equally to all platforms. | ||
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| The edit dialog invoked either by selected Modify Force Structures under the Force Menu or by the Pipeline command [[Visual3D: | The edit dialog invoked either by selected Modify Force Structures under the Force Menu or by the Pipeline command [[Visual3D: | ||
| - | {{AMTI_steps2.jpg}} | + | {{:AMTI_steps2.jpg}} |
| Each structure is defined as a plane (or polygon) defined by four corners. | Each structure is defined as a plane (or polygon) defined by four corners. | ||
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| For example, the following force structure has one surface attached to two force platforms. | For example, the following force structure has one surface attached to two force platforms. | ||
| - | {{ForceStructureDlg1x2.jpg}} | + | {{:ForceStructureDlg1x2.jpg}} |
| \\ | \\ | ||
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| The following dialog creates a force structure that is comprised of 2 surfaces attached to the same platform. | The following dialog creates a force structure that is comprised of 2 surfaces attached to the same platform. | ||
| - | {{AMTI_steps3.jpg}} | + | {{:AMTI_steps3.jpg}} |
| Visual3D creates two surfaces, so it creates two force signals. | Visual3D creates two surfaces, so it creates two force signals. | ||
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| **COP_1**, **FORCE_1** and **FREEMOMENT_1** | **COP_1**, **FORCE_1** and **FREEMOMENT_1** | ||
| - | {{ForceStructureDataTree.jpg}} | + | {{:ForceStructureDataTree.jpg}} |
| In the following figure the right foot makes contact with 2 steps | In the following figure the right foot makes contact with 2 steps | ||
| - | {{ForceStructureGraph.jpg}} | + | {{:ForceStructureGraph.jpg}} |
| ==== Structure consisting of 2 force platforms and 1 surface ==== | ==== Structure consisting of 2 force platforms and 1 surface ==== | ||
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| The following dialog creates a force structure that is comprised of 1 surface spanning 2 force platforms. | The following dialog creates a force structure that is comprised of 1 surface spanning 2 force platforms. | ||
| - | {{ForceStructureDig1x2.jpg}} | + | {{:ForceStructureDig1x2.jpg}} |
| The user has the option to treat each force independently, | The user has the option to treat each force independently, | ||
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| * solve the following 6 equations for the resultant force and moment | * solve the following 6 equations for the resultant force and moment | ||
| - | {{ForceStructureEqn1.jpg}} solve for the 3 components of the force | + | {{:ForceStructureEqn1.jpg}} solve for the 3 components of the force |
| - | {{ForceStructureEqn2.jpg}} assume the resultant center of pressure lies on the output surface, and that the Free Moment is computed only about the normal to the surface | + | {{:ForceStructureEqn2.jpg}} assume the resultant center of pressure lies on the output surface, and that the Free Moment is computed only about the normal to the surface |
| * solve for the x and y component of the COP on the surface | * solve for the x and y component of the COP on the surface | ||
visual3d/documentation/kinematics_and_kinetics/external_forces/force_structures.1720792842.txt.gz · Last modified: 2024/07/12 14:00 by sgranger