Yoshiro Nojiri

Relative movement evaluation between developed distributed-type tactile sensor and the contacting object

This paper describes an output algorithm that measures forces and moment acting on a developed distributed-type tactile sensor and evaluates relative movement with the contacting object. To realize advanced manipulation, it is necessary to acquire forces and moments acting on the fingertips of the robot hand; it is also necessary to evaluate the relative movement between the contacting object and the sensor. An output algorithm for evaluating the relative movement for developed tactile sensor was created whose effectiveness was shown by experiments.

Characteristics of tactile sensor and movement detection of attached object

To realize a dexterous robot hand, we must acquire information at the robots fingertips. A tactile sensor has been developed for dexterous robot hands. Since this tactile sensor consists of multiple three-axis force sensors with strain gauges, it enables to get force and torque information at robots fingertips. In this paper, the static characteristics of the three-axis force sensor that is a part of the tactile sensor are demonstrated, and the best experimental method to obtain accurate and precise force values is proposed. Furthermore, theoretical and experimental results of attached object movement detection with this tactile sensor are described in this paper.

Development and structure evaluation of small sensor element for distributed-type tri-axial force sensor of robot finger

For the purpose of the development of a distributed-type tactile sensor for a robot finger, a small sensor element is developed, and an evaluation of its structure is carried out. In this paper, a small sensor element is presented the dimensions of which are 5 mm in length, 5 mm in width, and 1 mm in thickness. The sensors structure was evaluated by simulation and experiment from the viewpoints of strain gauge sensitivity, force sensitivity, conditional number, and rigidity. As a result, it was proven that the proposed sensor element could be miniaturized, and could measure tri-axial force.

Verification of Tactile Sensor for Manipulator

This paper describes the basic characteristics of a distributed-type tactile sensor that we developed for a manipulator. To create a dexterous manipulator, it is necessary to acquire reliable force information loaded on manipulator fingertips. In a previous paper, we illustrated that the tactile sensor can detect attached object movement. In this paper, FEM analysis and experiments demonstrate that the principles of the three-axis force sensor, which is a component of the tactile sensor, are applicable. Furthermore, uncertainty analysis reveals that the detected movements of the tactile sensor are precious. Consequently, these results demonstrate that this tactile sensor is available for manipulators.

Acquisition of Slip Phenomenon between Developed Distributed-Type Force Sensor and the Contacted Object

This paper describes output algorithms to evaluate slip, using our developed distributed-type force sensor. To realize advanced manipulation, it is necessary to acquire the forces and moments applied to the fingertips of the robot hand, and to evaluate the slip between the contacted object and the sensor. The algorithms continuously detect translational micro- and macro-slip. Micro-slip is detected from vibration information output by strain gauges attached to the surface of each sensor element, while macro-slip is detected as movement of the center of pressure distribution. The experiments demonstrate the effectiveness of this algorithm