Daisuke Tsuchimi

Development of a Haptic Sensor System for Monitoring Human Skin Conditions

Human skin, which mainly consists of epidermis, dermis and hypodermis, is the largest organ of a human body. It has a lot of roles, for example, protection function, moisture maintenance function and sensory function. Moreover, it becomes a parameter for estimation of the health condition and beauty, because the skin is the outermost layer of a human body. At present, ocular inspection and palpation are generally used for detection of human skin condition such as surface appearance, and extensibility. Ocular inspection and palpation are important diagnosis procedures to examine patient’s skin condition quickly. However, it is difficult to quantify an evaluation by these diagnosis procedures, because it is very subjective. A development of handy method in order to evaluate the skin condition objectively is craved to dermatologists, and cosmetic industries. So far, various methods of evaluating skin condition objectively have been developed. However, these methods are substitutions of ocular inspection, or only measure some specific physical parameters of skin such as elasticity.

Haptic perception mechanism of softness

A palpation is convenient and it is a useful method to detect a cancer and to evaluate softness of skin. However, the palpation is skillful method, and the mental/physical conditions of the experts affect the result of the palpation easily. The result of palpation is subjective and it is hard to share the result with the other people. Therefore, the development of the sensor that can measure the softness of the body is demanded. In this paper, a relationship between physical properties of measured objects and the softness that human feel are investigated for a development of a tactile sensor system. At first, the relationship between tactile softness and stiffness of the measured objects is investigated. As a result, tactile softness decreases with the increase of stiffness of the objects. Next, the relationship between tactile softness and size of contact area of human finger are investigated. These results lead to the conclusion that there is a possibility that tactile softness of the objects are not only related to the contact force or displacement of a finger and the objects but also to the contact area of the finger and the measured objects.

Advanced haptic sensor for measuring human skin conditions

This paper is concerned with the development of a tactile sensor using PVDF (Polyvinylidene Fluoride) film as a sensory receptor of the sensor to evaluate softness, smoothness, and stickiness of human skin. Tactile sense is the most important sense in the sensation receptor of the human body along with eyesight, and we can examine skin condition quickly using these sense. But, its subjectivity and ambiguity make it difficult to quantify skin conditions. Therefore, development of measurement device which can evaluate skin conditions easily and objectively is demanded by dermatologists, cosmetic industries, and so on. In this paper, an advanced haptic sensor system that can measure multiple information of skin condition in various parts of human body is developed. The applications of the sensor system to evaluate softness, smoothness, and stickiness of skin are investigated through two experiments.

Haptic perception mechanism of softness - second report, relationship between stiffness of an object and softness sensation

A palpation is a useful method to detect cancer and to evaluate skin or under skin conditions. However, the palpation is a skillful method. Doctors mental and physical conditions affect diagnoses by the palpation. Additionally, it is hard to share the feeling of palpation with other people because palpation is subjective skill. Therefore, the development of the sensor that can measure the skin and under skin condition of the body like softness as a doctors palpation is demanded. In this paper, we focus on a haptic perception mechanism of human for evaluating the softness. Six objects are made to conduct sensory tests. The silicone rubber part of the objects has two kinds of thickness and three kinds of Youngs modulus. Relationships between physical properties of evaluated objects and the softness that human feel in active touch are investigated. After that, to control the contact condition between objects and finger, a passive touch evaluation system is fabricated. Using the system, relationships between the stiffness of the objects and evaluated haptic softness are investigated under passive touch condition.

MECHANISM OF HAPTIC PERCEPTION: INFLUENCE OF AMPLITUDE AND FREQUENCY FOR SMOOTHNESS

Tactile sense is one of the fundamental senses, and some tactile sensations which are obtained through the active touch have an important role in our life. For instance, palpation that can quickly examine patient’s skin condition is one of the important diagnosis procedures. However, tactile sensations are said to be ambiguous, subjective and much affected by the physician’s experience. As a result, it is difficult to quantify the information obtained by tactile sensations and share the information with others. Therefore, a development of an objective measurement sensor system for evaluation of tactile sensations is demanded. In order to developing the objective haptic sensor system, it is necessary to find out the mechanism and characteristic of tactile sensation. In this paper, a simple tactile display that subjects can feel various degree of smoothness is developed. Three bimorph cells are used as actuator to generate vibratory stimulus. Through two experiments, the relationship between the amplitude and frequency distribution of vibratory stimulus and the smoothness feeling are investigated.