Tactile Robotic Skin with Pressure Direction Detection

Abstract

Tactile sensing is the current challenge in robotics and object manipulation by machines. The robot’s agile interaction with the environment requires pressure sensors to detect not only location and value, but also touch direction. The paper presents a new, two-layer construction of artificial robotic skin, which allows measuring the location, value, and direction of pressure from external force. The main advantages of the proposed solution are its low cost of implementation based on two FSR (Force Sensitive Resistor) matrices and real-time operation thanks to direction detection using fast matching algorithms. The main contribution is the idea of detecting the pressure direction by determining the shift between the pressure maps of the skin’s upper and lower layers. The pressure map of each layer is treated as an image and registered using a phase correlation (POC–Phase Only Correlation) method. The use of the developed device can be very wide. For example, in the field of cooperative robots, it can lead to the improvement of human machine interfaces and increased security of human–machine cooperation. The proposed construction can help meet the increasing requirements for robots in cooperation with humans, but also enable agile manipulation of objects from their surroundings.

Human Body Parts Proximity Measurement Using Distributed Tactile Robotic Skin

“…The robotic skin presented in the manuscript was screen-printed on the flexible film [ 1 ]. It can function in two modes: measuring the location and value of pressure from the touch, and measuring the proximity of human body parts.…”

“…However, in order to present the measurement of the proximity, a matrix of FSR sensors with a size of 16 × 16 cells was used. Details of the matrix structure can be found in Reference [ 1 ]. For proximity measurement purposes, each of the columns and rows are connected to each other ( Figure 1 a) and act as open capacitor working plate described in Section 3.2 .…”

“…The developed device acquires the pressure map from 16 × 32 FSR matrix at a rate of 48 frames per second, which is equivalent to one measuring cycle every 21 ms. Selected components affecting this speed and other details of the electronic touch measurement system can be found in Reference [ 1 ]. It is worth noting that the work described in this manuscript has managed to accelerate the measuring cycle of the touch measuring system by 9 ms (in Reference [ 1 ], the measuring cycle of 30 ms is described).…”

“…Selected components affecting this speed and other details of the electronic touch measurement system can be found in Reference [ 1 ]. It is worth noting that the work described in this manuscript has managed to accelerate the measuring cycle of the touch measuring system by 9 ms (in Reference [ 1 ], the measuring cycle of 30 ms is described). An example of hand touch visualization is shown in Figure 2 .…”

Tactile Sensors for Parallel Grippers: Design and Characterization

“…The latter are more frequently used to measure contact force intensity or magnitude. Both sensor principles may be supported by different transduction technologies, e.g., resistive [ 1 , 2 , 3 ], capacitive [ 4 , 5 ] and magnetic [ 6 , 7 , 8 ], which can be selected depending on the costs, weight, integration level, dimensions and specific task to perform. The number of papers on this subject is very large and here are reported only some among the most recent.…”