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Даниил Грабарь 3a5bc28bba feat: add release-to-move TCP gizmo control in Webots

Add a native Webots marker for setting the active tool's TCP position and
orientation. Dragging edits the preview; releasing the mouse submits one
complete, checked joint trajectory with configured TCP speed limits.
Unreachable targets reset the marker to the current TCP.

Preserve coordinate, joint, and control-file commands through motion
reservations and a controller action proxy. Give the gizmo lowest priority
and finish its committed trajectory before dispatching queued regular
commands, including waits longer than the former two-second service timeout.

Place the patron TCP at its working end, 55.2 mm along local Z, and use the
flange TCP when no tool is attached. Add digital_twin.tcp_gizmo configuration,
ROS interfaces, launch integration, and regression coverage.

Document operation, configuration, tool attachment, speed limits, and
troubleshooting in both Russian and English.

Validation: 42 Python tests and 8 C++ tests passed. Webots regressions covered
one action per release, translation and rotation with and without a tool,
unreachable targets, and ordinary commands waiting for gizmo completion.

2026-09-17 17:11:53 +03:00

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Simulation (Webots)

Webots is an open-source robot simulator. LWC uses it as a digital twin of the KUKA LBR IIWA 7, allowing control algorithms to be developed and debugged without a physical robot.

Key features

The simulator uses the same ROS 2 topics and interfaces as the real robot.
The simulation world is set in cobot-setting.yaml → digital_twin.webots.world.
Start it with cobot run --simulate.

TCP gizmo

This simulation-only mode lets you specify the robot's target pose by dragging a marker at its tool center point (TCP) in the Webots window.

Enable digital_twin.tcp_gizmo.enabled: true in cobot-setting.yaml and launch with cobot run --simulate.
Wait until other robot motions finish. For an initial test, use the regular named-pose command to move to work.
Select the TCP marker in Webots. Drag a translation arrow or rotation handle with the left mouse button. The robot remains stationary while you edit the target.
Release the button to submit the target. One complete trajectory is sent to the controller, rather than a stream of actions during dragging.
Wait for completion before dragging again. If the target cannot be reached or the checked path collides, the marker returns to the actual TCP.

Regular coordinate, joint, and control-file commands remain available. They have priority over new gizmo gestures. An already started gizmo trajectory finishes before a waiting regular command proceeds, even when that wait exceeds two seconds.

Tool attachment and speed

The marker follows the active tool's tcp frame. With patron, it is at the chuck's working end; with no tool, it is at the flange. Apply tool changes through cobot robot-setup, rebuild, and restart the simulation. New tool models must define tcp at their working point.

max_linear_speed (m/s) and max_angular_speed (rad/s) are upper bounds. Short moves include acceleration and braking, and joint limits may make motion slower. Joint interpolation reaches the requested TCP pose but does not guarantee a straight Cartesian path.

Set digital_twin.tcp_gizmo.enabled: false and restart to disable this mode. The configuration reference describes all parameters. command_timeout checks the age of the submitted target; mouse release is detected directly and requires no waiting-time setting.

When the marker returns or does not respond

Wait for regular motions or a committed gizmo trajectory to finish before starting another drag.
For a rejected target, read TCP gizmo rejected target: ... in the launch output. Try a smaller displacement from a reachable posture such as work.
With missing or stale robot feedback, the gizmo cannot submit movement. Check that simulation is running and /joint_states updates.

Differences from the real robot

Motion still obeys configured joint and TCP limits; simulation does not reproduce all physical robot protections.
Physics is approximate, including inertia, friction, and elasticity.
FRI is not used; communication goes through the Webots ROS 2 driver.

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