The topics covered in this section include:
The inverse kinematics (IK) tasks file <IKTaskSet> referred to from the main __40__Scale Setup File is shown in the example below. The IK tasks file specifies properties associated with error terms. A brief description of the tags used to describe these properties is given below. The section on __40__Inverse Kinematics provides more details.
Marker Tasks
The <IKMarkerTask> tags are used to specify the weights associated with the marker error terms in the IK formulation. See the IK chapter (__40__Inverse Kinematics) for more details.
Example: XML markup for an inverse kinematics tasks set
<IKTaskSet name="gait2354_Scale">
<objects>
<IKMarkerTask name="Sternum"> <weight>1</weight> </IKMarkerTask>
<IKMarkerTask name="R.Acromium"> <weight>1</weight> </IKMarkerTask>
<IKMarkerTask name="L.Acromium"> <weight>1</weight> </IKMarkerTask>
<IKMarkerTask name="Top.Head"> <weight>1</weight> </IKMarkerTask>
<!– . . additional <IKMarkerTask> tags cut for brevity . . –>
<!– Coordinates –>
<IKCoordinateTask name="subtalar_angle_r"> <value>0</value> </IKCoordinateTask>
<IKCoordinateTask name="mtp_angle_r"> <value>0</value> </IKCoordinateTask>
<IKCoordinateTask name="subtalar_angle_l"> <value>0</value> </IKCoordinateTask>
<IKCoordinateTask name="mtp_angle_l"> <value>0</value> </IKCoordinateTask>
<IKCoordinateTask name="lumbar_extension">
<value>0</value>
<weight>1000.0</weight>
</IKCoordinateTask>
</objects>
</IKTaskSet>
Coordinate Tasks
The <IKCoordinateTask> tags are optional and are used to specify properties associated with the coordinate error terms in the IK formulation. See the IK chapter (__40__Inverse Kinematics) for more details. In the example above, the subtalar and mtp angles are locked, and are assigned to the constant value of 0 radians. Additionally, we have a task which attempts to keep the (unprescribed) lumbar_extension coordinate close to 0 by setting its desired value to 0 and giving it a large weight.