Article

Kirigami Design of Flexible and Conformal Tactile Sensor on Sphere‐shaped Surface for Contact Force Sensing

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Abstract

Flexible tactile sensors can be used as the human–machine interactions for tactile information. Integration of flexible tactile sensor onto complex curved surfaces usually generates high assembly strains or stresses, thus reducing the accuracy of tactile sensing. This paper presents a novel flexible tactile sensor using a devisable kirigami structural design for conformal integration of curved surfaces with low assembly strain. The target sphere object's surface is divided into several fan‐shaped pieces and then flattened into 2D patterns for the structural design and arrangement of tactile sensors. Each piece of tactile sensor has three sensing units including one triangular‐shaped and two quadrilateral‐shaped sensing units. The fabricated tactile sensor with tri‐unit and quad‐unit is characterized with the sensitivity of 0.0112 and 0.0081 kPa−1 in sensing range of 0–80 kPa, respectively. Numerical simulation results show the tactile sensor has generally low assembly strain (<1.0%) when integrated onto a tennis ball, and experimental results demonstrate that the relative changes of initial resistance and calculated sensitivity are less than 4.0% before and after integration. The contact force sensing in tennis ball games with different actions demonstrates the potential of using the designed tactile sensor for further athletic training and other applications. A flexible and conformal tactile sensor is developed to be integrated onto spherical surface for contact force sensing. Conformal structure contains contour shape designed by kirigami and patterned units to reduce the assembly strains and stress of tactile sensor. Applications of tennis ball motion detection demonstrate the feasibility of the tactile sensor for sports training and interactions between humans and sports equipment.

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