Biosignal-based relaxation evaluation of head-care robot

Such popular head care procedures as shampooing and scalp massages provide physical and mental relaxation. However, they place a big burden such as chapped hands on beauticians and other practitioners. Based on our robot hand technology, we have been developing a head care robot. In this paper, we quantitatively evaluated its relaxation effect using the following biosignals: accelerated plethymography (SDNN, HF/TP, LF/HF), heart rate (HR), blood pressure, salivary amylase (sAA) and peripheral skin temperature (PST). We compared the relaxation of our developed head care robot with the head care provided by nurses. In our experimental result with 54 subjects, the activity of the autonomic nerve system changed before and after head care procedures performed by both a human nurse and our proposed robot. Especially, in the proposed robot, we confirmed significant differences with the procedure performed by our proposed head care robot in five indexes: HF/TP, LF/HF, HR, sAA, and PST. The activity of the sympathetic nerve system decreased, because the values of its indexes significantly decreased: LF/HF, HR, and sAA. On the other hand, the activity of the parasympathetic nerve system increased, because of the increase of its indexes value: HF/TP and PST. Our developed head care robot provided satisfactory relaxation in just five minutes of use.

I. Introduction

People want both physical and psychological relaxation. Head-care and hair washing are essential ways not only to become clean but also to relax [1]. Head-cares provides such benefits as a clean scalp, clean hair, increased blood flow, improved scalp function, and stimulated mental states. Head-care is commonly conducted in barber shops, beauty salons, and care and massaging facilities. To wash hair more comfortably and effectively, many studies have focused on shampooing methods. Others examined physiological and psychological responses in a standardized procedure [2], [3], suggesting the benefits of warming, circulation-enhancing, and relaxation.