Researchers Develop Low-Cost Tactile Imaging Sensors to Measure Pressure Distribution

Touch, or tactile sensing, is basically vital for a range of real-life applications, from surgical medicine to robotics to sports science. Tactile sensors are based on the biological sense of touch and can help scientists to comprehend human perception and motion. Scientists from Osaka University have recently formulated a new method to perform pressure distribution measurement using tactile imaging technology.

Pressure is one of the main characteristics of touch, and tactile imaging can be used to measure stress or pressure distributions spanning an object of interest. The most common current method to tactile imaging includes the use of an array of sensors made up of pressure-sensitive materials. However, such arrays require intricate fabrication processes and place restrictions on the sensor design, and hence the requirement for a new technique, currently described in an article in IEEE Transactions on Industrial Electronics.

“The pressure between two conductors is directly related to the electrical contact resistance between them,” states Osaka University’s Osamu Oshiro. “We used this relationship to develop a sensor composed of a pair of electromechanically coupled conductors, where one conductor had a driving function and the other performed the probe function. This sensor has no need for pressure-sensitive materials and is simpler to manufacture.”

This approach enabled the development of a universal tactile sensor for contact pressure distribution measurement using basic conductive materials such as carbon paint. The design concept integrated innovation in mechatronics technology, which allowed development of a flexible sensor based on conventional conductors linked to electrodes, with a tomography-based method for defining the pressure distribution across the coupled conductors.

The suggested technique improved on earlier electrical impedance tomography-based tactile sensing methods to offer sensors with adjustable sensitivity, high positional accuracy, and range, and a comparatively simple fabrication process.

The sensors can be realized using various conducting materials, including conductive fabrics and paint. Sheet-type flexible sensors were fabricated, along with finger-shaped sensors produced by coating 3D-printed structures with conductive paint, to illustrate possible practical applications.

Shunsuke Yoshimoto, Lead Author, Osaka University

The ease of tuning of the sensitivity and sensing range and the pressure estimation precision means that this tactile imaging method is projected to enable advanced control of versatile robots. “These sensors are expected to be applicable in fields including remote device operation and industrial automation,” states co-author Yoshihiro Kuroda.