Makoto Sato

A 3d spatial interface device using tensed strings

This paper describes a 3D kinesthetic interface device using tensed strings. The results of the experiments on pick-and-place tasks show that not only sensations of collision but also weights of virtual objects are important in virtual environments.

Space interface device for artificial reality—SPIDAR

To realize the human interface which efficiently models a three-dimensional shape on a computer, it is necessary to provide an environment in which the shape model can be manipulated directly as the actual three-dimensional object. Such an environment is called the virtual work space. In the human manipulation of an object by hand, such sensations as visual, tactile (touch), and force are utilized unconsciously. To compose the virtual work space, it is important that the human be given such sensory information in an integrated way. Such information must totally be generated artificially by computer processing. Based on such an idea, this paper proposes anew a space interface device called SPIDAR, as the I/O device needed in composing the virtual work space. The device functions to derive the information concerning the finger position and to provide the force sense information to the finger tip. The virtual work space for generation and manipulation of the three-dimensional shape is composed using SPIDAR. An experiment is conducted to examine the effect of the force sense on the direct manipulation of the three-dimensional shape in the virtual work space, and the usefulness of the method is verified.

A Novel Seven Degree of Freedom Haptic Device for Engineering Design

Abstract:In this paper, the authors intend to demonstrate a new intuitive force-feedback device that is ideally suited for engineering design. Force feedback for the device is tension-based and is characterised by 7 degrees of freedom (3 DOF for translation, 3 DOF for rotation, and 1 DOF for grasp). The SPIDAR-G (SPace Interface Device for Artificial Reality with Grip) allows users to interact with virtual objects naturally by manipulating two hemispherical grips located in the centre of a device frame. Force feedback is achieved by controlling tension in cables that are connected between a grip and motors located at the corners of a frame. Methodologies will be discussed for displaying force and calculating translation, orientation and grasp using the length of 8 connecting cables. The SPIDAR-G is characterised by smooth force feedback, minimised inertia, no backlash, scalability and safety. Such features are attributed to strategic cable arrangement and control that results in stable haptic rendering. Experimental results validate the feasibility of the proposed device and example applications are described.

Electrophoretic Truing and Dressing for Spherical Resin-Bonded Diamond Wheels with Fine Grains.

Precision truing and dressing techniques using an electrophoretic phenomenon was developed for spherical resin-bonded diamond wheels with fine grains. Truing was carried out by bringing the wheel into contact with the anode, and dressing was carried out by bringing the wheel into contact With a gelled fiim on the anode. Both truing and dressing were conducted by moving the wheel around the cylindrical anode that was attached to an A. C. induction motor. In addition, the revolution speed of the anode was varied periodically to change the direction of the resultant velocity by means of which the wheel surface was scratched. It was connrmed through the truing test that the wheel surface was scratched multidirectionally so that alapped-like wheel surface without any unidirectional groove could be obtained. Also, it was confirmed by the dressing test that the gelled film on the anode behaved like a soft polisher, so that a sufficient chip pocket could be achieved without any residual damage on the bond surface.

Surface Modification of Diamond Grains and Reinforcement of a Bonding Material for Improvement of Wear Resistance of Resin-Bonded Wheels with Fine Grains.

Experimental research on preventing wheel wear of a resin-bonded diamond wheel that was used for mirror grinding of die materials was carried out. The gripping strength of diamond grains was increased by modifying their surfaces using radio-frequency sputtering and surface active agents. Also, the wear resistance of a bonding material was strengthened by varying the pH of the hardening catalyst and by mixing inorganic micropowder with the bonding material. The grinding tests revealed that the gripping strength of SiO2-sputtered diamond grains to the bonding material was highly strengthened by covering them with a silane coupling agent. This gripping strength increased proportionally with the density of SiO2 particles attached to the grain surfaces. It was also shown that a tightly cross-linked molecular network was generated under acidic conditions; therefore the wear resistance of the bonding material was improved when sodium acid pyrophosphate was used as the hardening catalyst.