FootPlateConditionalContact#
Creates a GRF prediction force plate
#include "<AMMR_TOOLS>\GRFPrediction/FootPlateConditionalContact.any"`
#FootPlateConditionalContact#
The class template generates the conditional-contact code which links the foot to the ground.
The class needs a few important arguments: The ground plane (PLATE_BASE_FRAME
)
is a reference system where the ground plane is located.
Together with arguments NORMAL_DIRECTION
this specifies the surface the model
is walking on. Another important argument is the NODES_FOLDER
, which is a
folder that contains all the contacts points.
The contact points can be created manually, but to avoid this we use another
class-template (CreateFootContactNodes25
) to create the nodes automatically.
As the name says it creates 25 nodes in the foot coordinate system. This part is
specific to the model implementation. One could also imagine class-templates
that produce a higher number of nodes or nodes in positions that corresponds to
particular shoes or on other body parts.
Example
The following example is from the model repository.
FootPlateConditionalContact GRF_Prediction_Right (
NORMAL_DIRECTION = "Y",
NUMBER_OF_NODES = 25,
NODES_FOLDER = FootNodes,
SHOW_TRIGGER_VOLUME = ON,
PLATE_BASE_FRAME = Main.EnvironmentModel.GlobalRef
) =
{
CreateFootContactNodes25 FootNodes (
foot_ref = Main.HumanModel.BodyModel.Right.Leg.Seg.Foot
) = {};
Settings.LimitDistHigh = 0.015; // Vertical height
};
Full signature
FootPlateConditionalContact <ObjectName>(
NORMAL_DIRECTION="Z",
NUMBER_OF_NODES=1,
PLATE_BASE_FRAME=Main.EnvironmentModel.GlobalRef,
SHOW_TRIGGER_VOLUME=0,
GLOBAL_REF=Main.EnvironmentModel.GlobalRef,
) = {
Settings = {
AnyComponentDefinition CDef = {
SubGroupRegexSearch = "([_[:alnum:]]+?)\.([_[:alnum:]]+?)";
};
NODES_FOLDER = {
AnyRefFrame Node## = <...>; (NUMBER_OF_NODES)
};
};
Arguments
- __CLASS__:
AnyFolder
- NORMAL_DIRECTION:
Defines the normal direction of the ground plane the in
PLATE_BASE_FRAME
coordinate system. (Default: “Z”)
- NUMBER_OF_NODES:
The number of contact nodes to expect within
NODE_BASE_FRAME
(Default: 1)
- PLATE_BASE_FRAME:
Is a AnyRefFrame object where the ground planes is attached. (Default: Main.EnvironmentModel.GlobalRef)
- SHOW_TRIGGER_VOLUME:
Visualize the volume where contacts may be triggered. (Default: 0)
- GLOBAL_REF:
The global reference. This must be set if the global reference is not
Main.EnvironmentModel.GlobalRef
(Default: Main.EnvironmentModel.GlobalRef)
Expected members
Settings = {
AnyComponentDefinition CDef = {
SubGroupRegexSearch = "([_[:alnum:]]+?)\.([_[:alnum:]]+?)";
};
/ Lower bound of the contact detection volume. #var AnyVar LimitDistLow = DesignVar(-0.10); FootPlateConditionalContact.Settings / Upper bound of the contact detection volume. #var AnyVar LimitDistHigh = DesignVar(0.04); FootPlateConditionalContact.Settings / Velocity threshold for contact detection. #var AnyVar LimitVelHigh = DesignVar(0.8); FootPlateConditionalContact.Settings / The size of the contact detection area. #var AnyVar Radius = DesignVar(1000); FootPlateConditionalContact.Settings / Strength of the contact elements. #var AnyVar Strength = DesignVar(200); FootPlateConditionalContact.Settings / Friction coefficient of the contact elements. / This adds limits to the amount of friction force / which can be recruited. #var AnyVar FrictionCoefficient = DesignVar(0.5);
#var AnyVar ScaleFactor = DesignVar(1);
FootPlateConditionalContact.Settings / Scale factor for the drawing of the GRF force vector. #var AnyVar ForceVectorDrawScaleFactor = DesignVar(0.0005); FootPlateConditionalContact.Settings / The ground velocity in the global reference system. #var AnyVec3 GroundVelocity = {0, 0, 0};
};
NODES_FOLDER = {
AnyRefFrame Node## = <...>; (NUMBER_OF_NODES)
};
A number of AnyRefFrame
objects used for the contact detection.
Optional initialization members
Settings.LimitDistLow = DesignVar(-0.10);
- class type:
AnyVar
Lower bound of the contact detection volume.
Settings.LimitDistHigh = DesignVar(0.04);
- class type:
AnyVar
Upper bound of the contact detection volume.
Settings.LimitVelHigh = DesignVar(0.8);
- class type:
AnyVar
Velocity threshold for contact detection.
Settings.Radius = DesignVar(1000);
- class type:
AnyVar
The size of the contact detection area.
Settings.Strength = DesignVar(200);
- class type:
AnyVar
Strength of the contact elements.
Settings.FrictionCoefficient = DesignVar(0.5);
- class type:
AnyVar
Friction coefficient of the contact elements. This adds limits to the amount of friction force which can be recruited.
Settings.ForceVectorDrawScaleFactor = DesignVar(0.0005);
- class type:
AnyVar
Scale factor for the drawing of the GRF force vector.
Settings.GroundVelocity = {0, 0, 0};
- class type:
AnyVec3
The ground velocity in the global reference system.
NODES_FOLDER.y = .OnOff;
- class type:
Opacit
A number of AnyRefFrame
objects used for the contact detection.
AnyRefFrame Node## = <…>; (NUMBER_OF_NODES)
–>Code for calculating COP #include “FootPlateConditionalContact_ForceMomentMeasure.any” ForceMomentMeasure_multiple ForceMomentMeasure_Auto(NODES = NUMBER_OF_NODES ) = {};
AnyVar Fx = ForceMomentMeasure_Auto.Fx_On_Human; AnyVar Fy = ForceMomentMeasure_Auto.Fy_On_Human; AnyVar Fz = ForceMomentMeasure_Auto.Fz_On_Human; AnyVar Mx = ForceMomentMeasure_Auto.Mx_On_Human; AnyVar My = ForceMomentMeasure_Auto.My_On_Human; AnyVar Mz = ForceMomentMeasure_Auto.Mz_On_Human;
#if NORMAL_DIRECTION == “X”
AnyVar Fxx =iffun(gtfun(abs(Fx),0.0), Fx, Fx+1e10);
AnyVar Rx = 0;
AnyVar Ry = -Mz/Fxx;
AnyVar Rz = My/Fxx;
AnyVar OnOff = iffun(gtfun(abs(Fx), 10.0), 1.0, 0.0);
#endif
#if NORMAL_DIRECTION == “Y” AnyVar Fyy =iffun(gtfun(abs(Fy),0.0), Fy, Fy+1e10); AnyVar Rx = Mz/Fyy; AnyVar Ry = 0; AnyVar Rz = -Mx/Fyy; AnyVar OnOff = iffun(gtfun(abs(Fy), 10.0), 1.0, 0.0); #endif
#if NORMAL_DIRECTION == “Z” AnyVar Fzz =iffun(gtfun(abs(Fz),0.0), Fz, Fz+1e10); AnyVar Rx = -My/Fzz; AnyVar Ry = Mx/Fzz; AnyVar Rz = 0; AnySwitch OnOff = iffun(gtfun(abs(Fz), 10.0), 1, 0); AnyIntVar OnOff = iffun(gtfun(abs(Fz), 10.0), 1, 0) ; #endif
AnyFloat RGlobal = transf3D({Rx,Ry,Rz},&PlateBaseFrame); AnyFloat FGlobal = {Fx,Fy,Fz}*PlateBaseFrame.Axes’; GRF_line. AnyDrawLine GRF_line= { AnyRefFrame & ref = .PlateBaseFrame; p0 = { .Rx, .Ry, .Rz}; p1 = p0 + 0.001 * {.Fx, .Fy, .Fz} ; Line.Thickness = 0.01; Line.RGB = {1, 0, 0}; GlobalCoord=Off;