Fingertip Force Measurement by Imaging the Fingernail
نویسنده
چکیده
Shear and normal forces from fingertip contact with a surface are measured by external camera images of the fingernail. Due to mechanical interaction between the surface, fingertip bone, and fingernail, regions of tension or compression are set up that result in reddening or whitening due to blood flow. The effect is quantitative enough to serve as a transducer of fingertip force. Due to individual differences, calibration is required for the highest accuracy. Automated calibration is achieved by use of a magnetically levitated haptic interface probe.
منابع مشابه
Understanding of Fingernail-Bone Interaction and Fingertip Hemodynamics for Fingernail Sensor Design
When the human fingertip is pressed against a surface or bent, the hemodynamic state of the fingertip is altered due to mechanical interactions between the fingernail and bone. Normal force, shear force, and finger extension/flexion all result in different patterns of blood volume beneath the fingernail. This phenomenon has been exploited in order to detect finger forces and finger posture by c...
متن کاملFinger Posture and Shear Force Measurement Using Fingernail Sensors: Initial Experimentation
A new method for measuring both the posture of human fingers and shear force at human fingertips is presented. Instead of using a traditional electronic glove with bending sensors embedded along the finger and shear sensors embedded beneath the fingertip, a wearable fingernail sensor is used to measure resulting changes in coloration of the fingernail. Since the sensor is mounted on the fingern...
متن کاملThe Common Patterns of Blood Perfusion in the Fingernail Bed Subject to Fingertip Touch Force and Finger Posture
When the human fingertip is pressed against a surface or bent, the hemodynamic state of the fingertip is altered in a way that is common to all people. Normal force, shear force, and finger extension/flexion all result in visibly distinct patterns of blood volume or perfusion beneath the fingernail. These patterns of blood perfusion can be used not only to monitor the state of the finger, but a...
متن کاملPhotoplethysmograph fingernail sensors for measuring finger forces without haptic obstruction
A new type of touch sensor for detecting contact pressure at human fingertips is presented. Unlike traditional electronic gloves, in which sensor pads are placed between the fingers and the environment surface, this new sensor allows the fingers to directly contact the environment without obstructing the human’s natural haptic senses. The finger touch force is detected by measuring changes in t...
متن کاملNon-linear viscoelastic models predict fingertip pulp force-displacement characteristics during voluntary tapping.
We evaluated whether lumped-parameter non-linear viscoelastic models of human fingertip tissue can describe fingertip force-displacement characteristics during a range of rapid, dynamic tapping tasks. Eight human subjects tapped with their index finger on the surface of a rigid load cell while an optical system tracked fingertip position using an infra-red LED attached to the fingernail. Four d...
متن کامل