We describe the development of a tactile hemispherical soft fingertip (FT) of a size similar to that of a human thumb. The sensory core consists of a microscaled force/torque sensor that can output one component of force and two components of moment simultaneously, which was developed beforehand. This sensor is embedded in a polyurethane rubber hemispherical dome to form a complete soft, compliant, and perceptible robotic FT. This system is designed for easy fabrication, high reliability in outputting signals, and stable operation. Static and dynamic mathematical analyses were utilized to investigate the responses of the sensor during the typical sliding motion of an FT. This was followed by experiments to show its potential in tactile and texture recognition. Especially, incipient-slip detection, which is critical in grasping manipulations, can be assessed properly and in a timely way. The development of this tactile FT is considered significant in the field of dexterous manipulation.

This paper describes our initial research on development of a tactile sensor, which can be employed in anthropomorphic soft fingertips, with multi-sensing points that uses 3-DOF micro force moment sensing chips (MFMS) which are able to measure forces up to nearly a Newton. Three sensing points are integrated on a compact printed circuit board with an in-built multiplexer circuit for the purpose of saving energy and reducing the number of outputs. This system was designed for the purpose of manipulating small-scaled objects, and realizing special characteristics of the objects such as distribution of edges/borders. The process including design, fabrication, and calibration will be explained in detail in this paper.

We have investigated the deformation of a soft fingertip when it slides. This process was first simulated using the non-linear Finite Element Analysis (FEA) method. Based on the results of this simulation, we designed experiments to observe the sliding and object grasping of a soft fingertip, in which a 3-DOF (degree of freedom) micro force/moment sensor was embedded. With this sensor, forces and moments acting in the fingertip are measured based on the piezoresistive effect. These measurements provide information on the status of contact and sliding of a soft fingertip on a surface. Based on these results, incipient slip, which has an important role in object gripping by a robot manipulator, can be realized. Textile's texture recognition experiments were also conducted to assess potentials of the fingertip in tactile and texture perception.

We have investigated the deformation of a soft fingertip when it slides. This process was first simulated using ANSYS software with non-linear Finite Element Analysis (FEA). Based on the results of this simulation, we designed experiments to observe the sliding and object grasping of a soft fingertip, in which, a 4-DOF (degree of freedom) micro force/moment sensor was embedded inside the soft fingertip. With this sensor, values of force and moment acting in the fingertip are measured, based on the piezoresistive effect. These measurements provide information on the status of contact and sliding of a soft fingertip on a surface. Based on these results, incipient slip, which has an important role in object gripping by a robot manipulator, can be realized.

A new type of passive element with variable mechanical impedance is proposed. Since the proposed elements are lighter, smaller and softer than the previous passive elements, these elements have the possibility to develop wearable robots. In the paper, the principles of the variable mechanical impedance are explained and the basic experimental results demonstrate the performance of the proposed element. Moreover, a wearable robot for virtual reality is developed by using the proposed element and it is shown that the developed wearable robot is utilized as a force display in the virtual world.

Considerable progress in silicon pressure sensors has been made in recent years. This paper discusses three types of vacuum-sealed silicon micromachined pressure sensors that represent the present state of the art in this important area. The devices are a capacitive vacuum sensor, a surface-micromachined microdiaphragm pressure sensor, and a resonant pressure sensor. Vacuum sealing for these devices is accomplished using anodic bonding, films deposited using low-pressure chemical vapor deposition, and thermal out-diffusion of hydrogen, respectively. These sensors emphasize high sensitivity, small size, and excellent stability, respectively. The silicon-diaphragm vacuum sensor uses electrostatic force balancing to achieve a wide pressure measurement range.