Patch/gripper in step action by hello-william · Pull Request #57 · hello-robot/stretch4_web_teleop

hello-william · 2026-08-24T17:54:41Z

Description

This PR fixes bug reported by @hello-lamsey #54.

Opening and closing gripper was not working in Step Action mode. This PR also addresses closely related bugs like should the visual states when gripper is opened/closed at its limit.

Testing procedure

Switch to Step Action mode.
Open and close gripper.

Before opening a pull request

From the top-level of this repository, run:

pre-commit run --all-files

To merge

Squash & Merge

hello-william · 2026-08-24T17:56:17Z

+}
+
+/** Remap stretch_gripper_joint → gripper_joint (+ finger_rad → pct) for trajectory goals. */
+function remapGripperForTrajectory(


Remapped operator stretch_gripper_joint (finger rad) → driver gripper_joint (pct) for FollowJointTrajectory.

hello-william · 2026-08-24T17:56:17Z

+     * pct-vs-world-rad units). Body first, then gripper-only, matches the path
+     * that Step Action already uses successfully.
+     */
+    private async runBodyThenGripperTrajectories(


Split pose playback into a) body trajectory and b) a gripper-only goal.

What's the rationale behind this? Are there errors if the gripper tracks a trajectory at the same time as other joints?

Yes — mixed gripper_joint + body FollowJointTrajectory goals time out. The driver commands gripper in pct but monitors world-rad pos, so the 3s action_timeout fires even after the hand has arrived

I wonder if this will be patched by @hello-garv here: https://github.com/hello-robot/stretch4_ros2/pull/26/changes

It looks like GripperCommandGroup::monitor_execution() is updated to fix this with the new gripper conventions.

In general, there are several bugs with the gripper behavior that we could either patch with the currently released software or patch after incorporating the PRs that are landing soon across the stack. If the gripper PRs will merge within a few days, I'm inclined to say that we should wait to fix this until those PRs get merged and we can update / test accordingly.

@hello-lamsey Oh ok. I may be able to wrap up this PR, but maybe I should pause?

@hello-garv Do you know if your PR will land in main soon?

hello-william · 2026-08-24T17:56:17Z

+        .filter((pose) => Object.keys(pose).length > 0);
+}
+
+function finalGripperPose(poses: RobotPose[]): RobotPose | undefined {


Multi-pose recordings keep the full body path but only the last gripper aperture.

What's the rationale for this? Users may want to record multiple gripper poses within a recording. For example, opening the gripper, extending the arm, and then closing the gripper to grab something.

Recording stores gripper on each waypoint when Hand is selected. During playback finalGripperPose / stripGripperFromPoses are gone, and every waypoint runs through the same body-then-gripper-only path as a single pose goal. Mid-path open > extend > close is preserved including a second play from the end pose.

hello-william · 2026-08-24T17:56:17Z

                        setTimeout(() => {
                            this.setButtonInactiveState(buttonPadFunction);
-                            this.setBaseVelocity(0.0, 0.0, 0.0);
+                            if (baseButtonPadFunctions.has(buttonPadFunction)) {


Step Action only calls setBaseVelocity(0) for base buttons now.

hello-lamsey · 2026-08-31T21:38:09Z

    translate_mobile_base: [-30.0, 30.0],
    rotate_mobile_base: [-3.14, 3.14],
-    stretch_gripper_joint: [-0.37, 0.17],
+    stretch_gripper_joint: [0.0, 0.425],


@hello-garv does this remap match the new gripper limits convention?

The hard coded joint limits should be removed entirely and pulled from the driver with the next update!

hello-lamsey · 2026-08-31T21:40:43Z

+ * GripperConversion.get_status (aperture_open_m / finger_length_m).
+ */
+const GRIPPER_TRAJECTORY_JOINT = "gripper_joint";
+const GRIPPER_PCT_CLOSED = -100;


Also @hello-garv will this change once we merge your new stretch4_body PR for grippers?

Yes, neither of these things should need to be hard coded.

@hello-garv Would it be possible to get this PR into main and then when the stuff in the other repo lands we do a smaller PR patch?

CC @hello-lamsey

hello-lamsey

Most functionality seems to work as expected. Two changes, one for sure and one maybe beyond the scope of this PR:

For sure - record gripper positions throughout a movement recording instead of keeping only the final gripper pose for the whole trajectory. Disallowing recording multiple gripper poses prevents users from teaching grasp / release sequences.
Maybe - assess the unit conversions used for the gripper in anticipation of upcoming changes to stretch4_body (hello-robot/stretch4_body#64)

hello-william · 2026-09-01T00:25:12Z

For sure - record gripper positions throughout a movement recording instead of keeping only the final gripper pose for the whole trajectory. Disallowing recording multiple gripper poses prevents users from teaching grasp / release sequences.

I'll work on this. I def think you're right that it should behave this. I'll keep you posted

Maybe - assess the unit conversions used for the gripper in anticipation of upcoming changes to stretch4_body (hello-robot/stretch4_body#64)

I'll let @hello-garv respond to this one because I think that was directed to her!

hello-william · 2026-09-01T19:08:30Z

+        return "success";
+    }
+
+    private async runSplitPose(pose: RobotPose): Promise<TrajectoryOutcome> {


Shared the body-then-gripper split between single-pose and playback.

hello-william · 2026-09-01T19:08:30Z

-                        alert_type: "error",
-                    });
-                }
+        for (const pose of poses) {


Dropped the already-at-final-pose skip so a second play from the end pose still walks every waypoint.

hello-william · 2026-09-01T19:16:39Z

@hello-lamsey I was able to just finish this PR because it was relatively straightforward.

Anna's work may collide with this stuff but, I figured that I might as well ship this so that it can be in a more solid place to pause it.

hello-garv · 2026-09-09T14:15:00Z

Superseded by #66

hello-william added 2 commits August 24, 2026 10:51

Fix gripper open/close in step action mode

47b161b

Update docs

3769743

hello-william linked an issue Aug 24, 2026 that may be closed by this pull request

Gripper not opening / closing in Step Action mode. #54

Closed

hello-william commented Aug 24, 2026

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hello-william self-assigned this Aug 29, 2026

hello-lamsey self-requested a review August 31, 2026 21:28

hello-lamsey reviewed Aug 31, 2026

View reviewed changes

hello-lamsey requested changes Aug 31, 2026

View reviewed changes

Refactor to allow full replay of gripper movements

b1f47a6

hello-william commented Sep 1, 2026

View reviewed changes

hello-william requested a review from hello-lamsey September 1, 2026 19:15

hello-garv closed this Sep 9, 2026

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hello-william commented Aug 24, 2026

Description

Testing procedure

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hello-william commented Sep 1, 2026

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hello-william commented Sep 1, 2026

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hello-garv commented Sep 9, 2026

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