Runtime evaluation and attachment#

Generated scripts translate semantic keypoints and axes into ObjectHandler lookups. Some lookups are evaluated repeatedly; others are sampled when a controller is constructed.

Live arguments versus sampled targets#

The generator wraps argument 0 of PosAlign, AxisAlign, PosWaypoint, AxisWaypoint, and PosDMPSpiral in a callable. For example:

# Recipe
PosAlign(g_eef_TCP, g_Ocube_Ptop_Lcenter, a_global_z, offset_clearance)

# Generated form
PosAlign(lambda: eef.get_k('TCP'), cube.get_k('top_center'),
         world.get_a('z'), offsets['clearance'])

The first argument reads the current tool keypoint during each error calculation. The target point and axis are evaluated when the controller is created for that subtask. They are not automatically redetected as an object moves.

Surface normals requested by the recipe are estimated from the acquired point cloud during script preparation and stored on their objects. The camera position from T_BASE_CAM is used to orient normals toward the camera.

What attachment means#

When a GripperControl packet references an object:

  • A close request converts that object’s stored points and axes into robot-relative coordinates.

  • An open request converts them back to world coordinates using the current robot pose.

An attached point can then follow the end effector through get_k(). This is a geometric assumption triggered by the command, not confirmation that the object was successfully grasped. It does not add perception-based tracking.

Frozen script geometry#

TOOL_TCP_OFFSET and TOOL_AXES are copied into generated code. A saved script retains those values even after the configuration changes. Restart the application and regenerate/review the script after changing tool geometry.

Parameter values are inserted as supplied; labels such as cm do not perform automatic unit conversion. See controller units.

Implementation anchors: gta/script_generator.py:apply_dynamic_parameters, gta/object_handler.py:ObjectHandler, and gta/error_projection.py:project_errors.