When we touch a human body, the flesh yields to our touch and we feel a sensation of softness. In virtual training systems for medical procedures such as palpation, the display of softness at the fingertips is essential. This paper proposes a softness-display device using a flexible sheet, and we present the concept of softness display at multiple fingers by combining the developed softness-display device and a multi-fingered haptic interface robot consisting of a five-fingered hand and an arm. Further, we carried out several experiments, the results of which show the validity of the proposed system and its great potential.

This paper presents the design of tool-type devices for a multifingered Haptic Interface Robot (HIRO), and summarizes the experimental results. HIRO consists of a robot arm with a five-fingered hand to which a variety of tools can be attached. The system is able to present the force sensation of many tool-type devices. In the medical field, manufacturing industry, and other fields, there are tools of a variety of shapes with a range of uses, and a haptic interface that can present the force sensation for many tools will be important for virtual training systems. HIRO has five fingers, and thus, we must clarify how many fingers need to be connected to the tool-type device and which fingers should be used for the connection. Solving these problems is important with regard to presenting an operator the force feeling through the tool-type device. To solve these problems, we propose an optimal connection method from the mobility and singularity points of view, and we have developed the tool-type devices for HIRO based on the proposed method. We describe here several experiments that were carried out to investigate the performance of the developed devices.