Contact state and slip precursors

The problem

Most failed grasps are not a matter of insufficient force — they are noticed too late. By the time a force sensor"s reading changes, the object is usually already moving; conventional accelerometers are too noisy and tend to notice late as well. Published end-to-end latencies from slip detection to suppression mostly sit in the tens to low hundreds of milliseconds.

For reference: tactile signals reach the human motor system in roughly 50 ms, and people rarely drop things. The difference is not reaction speed but the criterion — humans sense the precursor to slip, not slip itself.

How we approach it

Before an object actually slips, the contact interface develops high-frequency stick-slip vibration, well above the bandwidth a force sensor responds to. LUC-ANCHOR™ senses that 100 Hz – 10 kHz band optically, moving the criterion from “it slipped” to “it is about to”.

Where it applies

Grasping fragile or high-value items, handling objects with shifting centers of mass, monitoring clamping state during precision assembly.