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--- visual3d:documentation:kinematics_and_kinetics:external_forces:transform_from_fcs_to_lcs [2024/06/19 12:48] – sgranger
+++ visual3d:documentation:kinematics_and_kinetics:external_forces:transform_from_fcs_to_lcs [2024/07/17 15:45] (current) – created sgranger
@@ Line 1: / Line 1: @@
-transforming the force signals from the force platform coordinate system to the laboratory coordinate system
+====== Transform from FCS to LCS ======
-===== c3d parameter force_platform:corners =====
+Transforming the force signals from the Force Platform Coordinate System to the Laboratory Coordinate System
-the force platform corners are numbered from 1 to 4. the values are specified in the laboratory coordinate system in units consistent with the point data. the order is specified by the quadrant numbers in the force platform coordinate system. the order is (+x,+y), (-x, +y), (-x, -y), ( +x, -y).
+==== C3D Parameter FORCE_PLATFORM:CORNERS ====
-===== computing the transformation =====
+The force platform corners are numbered from 1 to 4. The values are specified in the Laboratory Coordinate System in units consistent with the POINT data. The order is specified by the quadrant numbers in the force platform coordinate system. The order is (+x,+y), (-x, +y), (-x, -y), ( +x, -y).
-visual3d calculates the transformation matrix from the force platform coordinate system to the laboratory coordinate system using the force platform corners. this transformation matrix is then used to transform the force vector from the force platform coordinate system (in which it was collected) into the laboratory coordinate system where it is used for the analysis.
+==== Computing the Transformation ====
-the force platform corners can be modified using the modify force platform parameters selection under the visual3d file menu transforming the ground reaction force into the laboratory coordinate system
+Visual3D calculates the transformation matrix from the force platform coordinate system to the laboratory coordinate system using the force platform corners. This transformation matrix is then used to transform the force vector from the force platform coordinate system (in which it was collected) into the laboratory coordinate system where it is used for the analysis.
-the following pseudo-code describes the algorithm for computing the transformation from the force platform coordinate system (fpcs) to the laboratory coordinate system (lcs)
+The Force Platform corners can be modified using the Modify Force Platform Parameters selection under the Visual3D File Menu Transforming the Ground Reaction Force into the Laboratory Coordinate System
+The following pseudo-code describes the algorithm for computing the transformation from the Force Platform Coordinate System (FPCS) to the Laboratory Coordinate System (LCS)
 x_vector = unit_vector(corner4 - corner3)
@@ Line 17: / Line 19: @@
 z_vector = cross_product(x_vector , y_vector)
 y_vector = cross_product(z_vector , x_vector)
-rotation matrix - fpcs to lcs
+Rotation Matrix - FPCS to LCS
 fpcs_to_lcs column1= x_vector
 fpcs_to_lcs column2= y_vector
 fpcs_to_lcs column3= z_vector
-location of top center of force platform in lcs
+location of top center of force platform in LCS
 platform_top_center_lcs= average(corner1, corner2, corner3, corner4)
 vector from plate origin to top center relative to lab
-rotate_to_lab(forceplatform_origin)
+Rotate_to_Lab(forceplatform_origin)
-vector from lcs origin to platform origin
+vector from LCS origin to platform origin
 platform_origin_lcs= platform_top_center_lcs- vector from plate origin to top center