Tactile Sensing of the Rigid-Soft Electromagnetic Feet of the iCrawl Robot for Pipe Size Classification

AbstractProper recognition of the terrain plays an important role in the smooth locomotion of walking robots. Many terrain recognition approaches use tactile sensory feedback to classify and map flat or irregular terrains. However, less attention has been given to the use of tactile sensing in the detection of round-shaped complex terrain such as industrial pipes with varying diameters. In this paper, we provide a solution to this problem by developing a rigid-soft electromagnetic robot foot for an inchworm-inspired pipe crawling robot, incorporating four appropriately positioned tactile sensors in the elastomeric part of the robot feet. By describing the sensor positioning criteria and soft toe fabrication method in detail, the new tactile sensing robot feet are tested on different industrial pipes and a flat surface. The recorded tactile sensory feedback is analyzed using an average value method. Based on the analysis, a confusion matrix is provided, where the success of the proposed tactile sensing addition in the soft toe is shown by classifying four different industrial pipe diameters and a flat plate. The results reveal the usefulness of tactile sensing and the way it is introduced into the robot feet to facilitate complex locomotion tasks with adaptability.KeywordsTactile sensorsSoft robotBio-inspired legged robotPipe diameter classificationInspection robot