Incipient slip detection method for soft objects with vision-based tactile sensor

A Novel Incipient Slip Degree Evaluation Method and Its Application in Adaptive Control of Grasping Force

“…First, in the first half of the phase where the tangential force increases, the degree of incipient slip is increasing, and more micro elements that were in the stick state become slip, leading to a decrease in the stick region and stick ratio. In this phase, there is an approximately linear negative correlation between the degree of incipient slip and stick ratio, which is consistent with the findings described in [11], [20]- [24]. The magnitude of the stick ratio in this case correctly reflects the degree of incipient slip.…”

“…The vision-based sensor contains an internal camera, often with a number of markers embedded in the surface, which enables the measurement of discrete deformation information on the contact surface by tracking the position of the markers. Several typical works include Goro Obinata et al [20], [21], Siyuan Dong et al [22], [23], and our work [11], [24]. This incipient slip degree evaluation method based on the area ratio of the stick/slip region has a clear physical meaning and can directly indicate the distance of the current state from macro slip (the complete disappearance of the stick region means that macro slip occurs).…”

“…Here we use the stick/slip region delineation method from the paper [11], which uses the deformation values on the finger contact region, and is applicable to objects with arbitrary flexibility and surface topography. We will use two visionbased sensors similar to the one used in [11] as the fingertips of the manipulator, which provides the contact deformation and distributed force required by this method.…”

“…As for the incipient slip, in a previous paper [11], we divided the incipient slip detection into two categories: qualitative and quantitative detections. Qualitative detections consider incipient slip as a state before macro slip occurs and determine whether incipient slip "occurs" by detecting some signal (e.g., vibration).…”

Marker Displacement Method Used in Vision-Based Tactile Sensors—From 2D to 3D: A Review

“… Optical flow method [28], [37]  Finite element mode [63], [44]  Neural network [58], [53] mainly using the machine learningbased approaches  Speckle detection [77], [80]  Feature enhancement [81], [82] mainly using the physical model-based approaches  Stereo vision [25], [94]  Virtual stereo vision [23], [26] mainly using the physical model-based approaches  Contact area [24]  2D force distribution [17]  Slip field [79]  Contact area [20]  2D force distribution [86]  Slip field [21]  Contact area [91]  Friction coefficient [23]  2D force distribution [97] 3D tactile perception  Geometric features [46]  3D geometry [18]  3D force distribution [63]  Geometric features [82]  3D geometry [82]  3D force distribution [87]  Geometric features [ commonly used in the field of visuotactile sensing. By using a camera to photograph the marks prepared on the sensor contact elastomer, a tactile image containing the position change of the markers can be obtained, and the tactile information can be further obtained by post-processing and analyzing the tactile image.…”