BTK Matlab Wrapper  0.3dev.0
Matlab bindings for the Biomechanical ToolKit library (BTK)
btkAppendForcePlatformType2 Class Reference

Description

Append a virtual force platform of type 2 (Fx,Fy,Fz,Mx,My,Mz).

Syntax:
btkAppendForcePlatformType2(h, forces, moments, corners)
btkAppendForcePlatformType2(h, forces, moments, corners, origin)
btkAppendForcePlatformType2(h, forces, moments, corners, origin, localframe)
Parameters
hHandle pointing to a C++ btk::Acquisition object.
forcesMatrix (n,3) where 'n' is the number of analog frames in the acquisition. If the given data corresponds to the number of point frames, these data will be then interpolated to fit the number of analog frames.
momentsMatrix (n,3) where 'n' is the number of analog frames in the acquisition. If the given data corresponds to the number of point frames, these data will be then interpolated to fit the number of analog frames.
cornersMatrix (4,3) corresponding to the location of the corners in the global frame (see detailed description for the order of the corners).
originColumn vector containing the location of the force plate origin related to it surface's center and expressed in the global frame.
localframeFlag (set to 0 by default) which indicates if the given forces and moments are expressed in the local or global frame.
Detailed description:
btkAppendForcePlatformType2(h, forces, moments, corners) creates a virtual force platform based only on the reaction forces and moments expressed in the global frame. This function updates all the metadata in the group FORCE_PLATFORM and append 6 analog channels.

btkAppendForcePlatformType2(h, forces, moments, corners, origin) sets also the origin of the force platform compare to its surface. The origin must be expressed in the frame of the force plate. Thus the verical component should be negative as the surface is higher than the origin. Setting the origin to an empty matrix has the same effect than giving an origin equals to [0,0,0].

btkAppendForcePlatformType2(h, forces, moments, corners, origin, localframe) create a virtual force platform using forces and moments expressed in the local frame if localframe is not set to 0. The content of corners and origin still must be expressed in the global frame. The use of localframe can be useful if you use data recorded directly from the force platform.

Note: The moment must be expressed at the (surface) origin of the plate. The corners are numbered from 1 to 4 and refer to the quadrant numbers in the X-Y plane of the force platform coordinate system (not the 3D point reference coordinate system). These are +x+y, -x+y, -x-y, and +x-y, with respect to the force plate coordinate system. The origin of the platform is set by default to [0,0,0] meaning that it has no thickness. If your forces and moments come from raw data recorded by a force platform (and then recorded to the location of the sensor), it is strongly advised to use the sensor distances given in the data sheet.

You can retrieve easily the data of the new force platform by using one of the following functions: