Passing an expert’s sensation on to the next generation

For: Craftspeople, education, and any site with skills worth keeping

The problem

Acquiring a skill depends on reflection — looking back at your own movement and at the movement you are modelling. But much of a skill is tacit knowledge that resists words, and the sense of how much force, applied at what moment, travels particularly poorly from person to person. Reflection through video has long been practised, but this method has structural limits.

  • Vision alone gives only a rough picture of how force is applied

    Watching a recording back leaves you to guess how much force the hands and fingers are applying. Those guesses are coarse — they stay at the level of finger position and the timing of a movement, and cannot reach the finer distribution of force.

  • Even your own sense of your force is off

    People often cannot say accurately how they themselves are applying force. You may believe you are applying it evenly while in fact favouring one side.

Reflection based on video alone therefore leaves mistaken beliefs about force uncorrected, and an expert’s sensations fail to carry over to the next generation.

Our approach

We record muscle activity in the forearm and vibration at the fingertips, synchronise them with video along a shared timeline, and play them back as touch — supporting reflection after the fact.

  • FMG (force myography) on the forearm

    Force sensors are placed evenly around the forearm, and how force is applied is recorded from the deformation of the muscles. We use FMG rather than EMG because it is less affected by perspiration and measures stably even in a hot, humid workshop.

  • Fingertip vibration sensors

    Accelerometers record the fine vibration at the fingertips as they meet the material.

  • Playback through haptic devices

    The recorded muscle activity and fingertip vibration are played back as skin stretch (rotational shear) and vibrotactile stimulation, so they can be experienced alongside the video after the movement.

Because the approach is record-and-replay, its main use is reflection after a movement rather than real-time assistance during one.

What we expect

Mistaken beliefs about force can be corrected

Across two workshops with six potters in Okinawa, a distribution of force that video alone conveyed only roughly became concretely graspable through haptic playback, and experts were observed correcting their own mistaken beliefs about how they applied force.

Conversation about someone else’s technique becomes concrete

Observers who re-experienced another potter’s recorded data through touch made similar discoveries, and their comments shifted from vague impressions to specifics about finger use and timing.

Products used

  • SenseFuse®

    A wearable sensor that combines muscle activity (FMG) with vibration sensing to record, hands-free, where and how much force a person is applying. It carries expert demonstration data into robot imitation learning and skill transfer.

  • FeelFuse®

    A wearable haptic device that returns the sensation of force to the hands in real time. Haptic teleoperation improves both the precision of an operation and the quality of the demonstration data used for imitation learning, and extends the experience in immersive content.

Projects