Spatial Calibration of Humanoid Robot Flexible Tactile Skin for Human-Robot Interaction

Recent developments in robotics have enabled humanoid robots to be used in tasks where they have to physically interact with humans, including robot-supported caregiving. This interaction-referred to as physical human-robot interaction (pHRI)-requires physical contact between the robot and the human body; one way to improve this is to use efficient sensing methods for the physical contact. In this paper, we use a flexible tactile sensing array and integrate it as a tactile skin for the humanoid robot HRP-4C. As the sensor can take any shape due to its flexible property, a particular focus is given on its spatial calibration, i.e., the determination of the locations of the sensor cells and their normals when attached to the robot. For this purpose, a novel method of spatial calibration using B-spline surfaces has been developed. We demonstrate with two methods that this calibration method gives a good approximation of the sensor position and show that our flexible tactile sensor can be fully integrated on a robot and used as input for robot control tasks. These contributions are a first step toward the use of flexible tactile sensors in pHRI applications.

Automated summary

Recent advances in robotics have allowed humanoid robots to physically interact with humans, particularly in robot-supported caregiving. This physical human-robot interaction (pHRI) necessitates physical contact, which can be enhanced through efficient sensing methods. In this study, we utilized a flexible tactile sensing array as a tactile skin for the humanoid robot HRP-4C. Our novel spatial calibration approach using B-spline surfaces accurately determines the locations and normals of the sensor cells when attached to the robot. We demonstrate the successful integration and use of our flexible tactile sensor for robot control tasks, marking a significant step in incorporating flexible tactile sensors in pHRI applications.