Contact Position Estimation for a Compact and Finger-shaped Tactile Sensor

Tactile sensing is an essential capability for robots performing manipulation tasks. By employing a tactile sensor, abundant contact information and surface properties can be perceived. The contact position is a key information to analyze the physical state of in-hand objects, which contributes to developing a grasping strategy. However, there are potential challenges in practical application of contact position estimation. Generally, such sensors are large and heavy, especially when a binocular camera is employed. Moreover, the sensing range of flat-shaped sensors is limited. In this study, we designed a finger-shaped tactile sensor with a monocular camera. Additionally, the mathematical model of the round sensing surface is built based on spherical fitting, and the contact position can be located through marker displacement. The experimental results demonstrate the effectiveness and accuracy of the method applied to the sensor.