Development of a full body multi-axis soft tactile sensor suit for life sized humanoid robot and an algorithm to detect contact states

Recognizing environmental contact on whole body of a humanoid robot can be very advantageous to work with people in human´s environment. In the tasks with environmental contacts, it is important as an interface with the environment to detect pushing, shearing and twist on the whole body of a robot such that it gets to know its current state and what to do next. In this paper, we describe a full body soft tactile sensor suit for a humanoid robot and an algorithm to calculate pushing, shearing, and twist for each sensor unit. These sensors are small muti-axis sensors with urethane structure and they can be placed densely on the body of a humanoid robot. We arranged 347 multi-axis soft tactile sensors on a humanoid robot imitating a human tactile sense to detect contact states. Then, we calculate a deformation vector for each muti-axis soft tactile sensor and detect the three contact states using deformation moment and average of deformation vectors in the contact surface consisting of soft tactile sensors. Finally, we confirmed the validity of the full body tactile suit and contact state detector by experiments of sitting on a wheelchair and passing object between a human and a robot.