Friction-based tactile sensor for measuring grip security
A system for estimating friction, the system including a contact surface including a plurality of protrusions extending from a base surface, the contact surface further including a first contact surface region and a second contact surface region, the first contact surface region being configured to resist slip less than the second contact surface region, and a sensor arrangement configured for detecting displacement of at least three of the plurality of protrusions in three different dimensions to measure a three-dimensional force applied to the at least three plurality of protrusions at a moment of slippage of the first contact surface region.
1 . A system for estimating friction, the system comprising:
a contact surface comprising a plurality of protrusions extending from a base surface, the contact surface further including a first contact surface region and a second contact surface region, the first contact surface region being configured to resist slip less than the second contact surface region; and
a sensor arrangement configured for detecting displacement of at least three of the plurality of protrusions in three different dimensions to measure a three-dimensional force applied to the at least three of the plurality of protrusions at a moment of slippage of the first contact surface region.
2 . The system of claim 1 , wherein displacement of the plurality of protrusions is a result of a translation or a rotation of an object being gripped.
3 . The system of claim 1 , wherein the system is further configured to estimate torque applied to the at least three of the plurality of protrusions.
4 . The system of claim 1 , wherein the system is further configured to sense vibration in the at least three of the plurality of protrusions relating to slip events.
5 . The system of claim 1 , wherein the system is further configured to sense vibration in the at least three of the plurality of protrusions at different surface textures.
6 . The system of claim 1 , wherein the plurality of protrusions are deformable.
7 . The system of claim 1 , wherein the plurality of protrusions are elongated shafts extending from the base surface to a tip, the contact surface being provided at or near the tip.
8 . The system of claim 1 , wherein the plurality of protrusions are positioned to form an array.
9 . The system of claim 1 , wherein the plurality of protrusions are configured to move independently of one another.
10 . The system of claim 1 , wherein the plurality of protrusions are configured such that, in use under a consistent grip pressure, a normal force on a protrusion in the first contact region is less than that on a protrusion in the second contact region.