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A careful grip: testing G1 tactile control for mandarin harvesting

The video re-renders recorded simulation poses with updated orchard visuals; it is not live camera footage. On-screen captions are in Japanese, with English explanations below.

When we pick up a mandarin, we adjust our grip by feel. Too much force can damage it; too little can let it slip. We are exploring how a robot can make those adjustments.

Team Z is developing a mandarin-harvesting simulation with the G1 humanoid robot. We have tested contact-responsive finger control and a mechanism that stops motion progression when excessive force is detected. Stable holding and harvesting remain in development.

Damage-free harvesting has not been achieved. Hardware harvesting and VLA training for this task are also not complete.

A replay of hand, finger and fruit poses recorded in Isaac Sim 6, rendered with the latest orchard visuals. The fruit is still supported by its simulated stem, not by the hand alone. Surrounding foliage is for presentation; its physical interactions require separate verification. Japanese captions identify approach, contact-responsive adjustment and the force-triggered stop.

Seeing contact does not tell us the grip force

We use forces from simulated contact as virtual tactile feedback to adjust finger movement. These are provisional sensor settings, not a calibrated reproduction of measurements from a physical hand.

Show / hide concept animationConcept animation of finger movement and tactile feedback, not experiment footage.
Concept animation of tactile feedback; not a replay of measured forces.
Concept animation of tactile feedback; not a replay of measured forces.

Stopping matters as much as moving

In the tested sequence, excessive force was detected as the motion moved toward twisting, and progression stopped. This demonstrates a stopping mechanism, not a successful harvest. The settings do not establish a damage threshold for real mandarins.

Harvesting stages and the current verification scope.
Harvesting stages and the current verification scope.

Developing the environment and the contact motion

The orchard layout combines tree rows, paths, ground and a distant forest. It is a visual prototype, not a surveyed reconstruction of a real farm. Repeated tree shapes and artificial-looking ground still need work.

A 3D orchard layout study, not a photograph or evidence of harvesting success.
A 3D orchard layout study, not a photograph or evidence of harvesting success.

We plan to photograph a real fruit-bearing branch from multiple angles to improve close-up fruit, leaves and branches. Visual quality and physical validity need separate checks.

Task decisions and local force adjustment

A vision-language-action model, or VLA, selects robot actions from images and instructions. Our intended approach combines task decisions with contact-responsive adjustment at the hand.

Concept animation of the intended architecture. VLA training is not complete.
Concept animation of the intended architecture. VLA training is not complete.

The finger control tested here was not learned by a VLA. We first need reliable holding, detachment and transport before collecting successful task demonstrations.

Next: supporting the fruit reliably

Our goal extends beyond making contact: support the fruit, detach it and carry it without dropping it. We are recording failures as we develop both the environment and the control.

Read the Japanese edition →

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