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Author

Junji Oaki

Other affiliations: Keio University
Bio: Junji Oaki is an academic researcher from Toshiba. The author has contributed to research in topics: Robotic arm & Robot control. The author has an hindex of 12, co-authored 57 publications receiving 574 citations. Previous affiliations of Junji Oaki include Keio University.


Papers
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Patent
28 Sep 2009
TL;DR: In this paper, a robot control apparatus includes: a drive unit (101) driving an actuator (115) based on a torque command value; a drive torque estimation unit (107) estimating the drive torque from a joint shaft angle; an external torque calculation unit (108) calculating a difference between the estimated drive torque and the torque command values as an external force; and a correction amount calculation unit(110) calculating the correction amount from the external force.
Abstract: A robot control apparatus includes: a drive unit (101) driving an actuator (115) based on a torque command value; a drive torque estimation unit (107) estimating a drive torque from a joint shaft angle; an external torque calculation unit (108) calculating a difference between the estimated drive torque and the torque command value as an external torque; a Jacobian matrix calculation unit (105) calculating a Jacobian matrix based on the joint shaft angle; an external force calculation unit (109) calculating an external force from the Jacobian matrix and the external torque; and a correction amount calculation unit (110) calculating a correction amount from the external force.

111 citations

Patent
Junji Oaki1
29 Feb 1988
TL;DR: In this article, a control unit for a multi-degree-of-freedom manipulator comprising a torque sensor for detecting the force exerting on each joint shaft and operational means for adding first and second correction values to the input signals to the motor actuator in accordance with the torque signal produced from the torque sensor is presented.
Abstract: A control unit for a multi-degree-of-freedom manipulator comprising a torque sensor for detecting the force exerting on each joint shaft and operational means for adding first and second correction values to the input signals to the motor actuator in accordance with the torque signal produced from the torque sensor. With this construction, non-linear and interference forces as well as effects due to the low rigidity of the joints can be removed without identifications of the link or arm parameters, and a striking improvement of the control performance can be achieved.

54 citations

Patent
24 Feb 2006
TL;DR: In this paper, an image correction device for use in a pattern inspection apparatus is disclosed, which has automatic adaptability to variations in density of a pattern image of a workpiece being tested.
Abstract: An image correction device for use in a pattern inspection apparatus is disclosed, which has automatic adaptability to variations in density of a pattern image of a workpiece being tested. The device is operable to identify a two-dimensional (2D) linear predictive model parameters from the pattern image of interest and determine the value of a total sum of these identified parameters. This value is then used to switch between a corrected pattern image due to the 2D linear prediction modeling and a corrected image that is interpolated by bicubic interpolation techniques. A pattern inspection method using the image correction technique is also disclosed.

39 citations

Patent
Junji Oaki1
22 Jun 2010
TL;DR: In this article, a robot control device according to an embodiment includes: an observer receiving the angular velocity of the motor and the current command value, and estimating an angular acceleration of the link, and angular velocities between the link and the motor from a simulation model of an angular velocity control system of the motors.
Abstract: A robot control device according to an embodiment includes: an observer receiving the angular velocity of the motor and the current command value, and estimating an angular acceleration of the link, and angular velocities of the link and the motor from a simulation model of an angular velocity control system of the motor; a first feedback unit calculating an axis torsion angular velocity from a difference between the angular velocities of the link and the motor estimated by the observer, and giving feedback to the angular velocity control system; a second feedback unit feeding back the angular acceleration of the link estimated by the observer to the angular velocity control system; and a first feedback constant calculating unit compensating an end effector load mass and increases inertia at the second feedback unit when an end effector load in the nonlinear dynamic model has low inertia.

30 citations

Journal ArticleDOI
TL;DR: An experimental test bed is built connecting Tsukuba and Kawasaki in Japan via an integrated services digital network, and an on-line predictive graphics simulator is incorporated to cope with image feedback delays from the remote site.

29 citations


Cited by
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Journal ArticleDOI
TL;DR: A literature review of the recently developed technologies related to the kinematics, dynamics, control and verification of space robotic systems for manned and unmanned on-orbit servicing missions is provided in this article.

825 citations

Patent
Khurram Zafar1, Sagar A. Kekare1, Ellis Chang1, Allen Park1, Peter Rose1 
20 Nov 2006
TL;DR: In this paper, a computer-implemented method for binning defects detected on a wafer includes comparing portions of design data proximate positions of the defects in design data space.
Abstract: Various methods and systems for utilizing design data in combination with inspection data are provided. One computer-implemented method for binning defects detected on a wafer includes comparing portions of design data proximate positions of the defects in design data space. The method also includes determining if the design data in the portions is at least similar based on results of the comparing step. In addition, the method includes binning the defects in groups such that the portions of the design data proximate the positions of the defects in each of the groups are at least similar. The method further includes storing results of the binning step in a storage medium.

528 citations

Proceedings ArticleDOI
05 Dec 2005
TL;DR: The RT-component, which is a basic software unit of RT-middleware based system integration, is derived from this discussion and a methodology of system development by using RT-components, and a framework for component development are proposed.
Abstract: In this paper, we propose RT-middleware for robot system integration. "RT" means "robot technology", which is applied not only to industrial field but also to nonindustrial field such as human daily life support systems. RT-middleware which is proposed in this paper is a software platform for RT systems. We have studied modularization of RT elements and have developed RT-middleware, which promotes application of RT in various fields. Robotic system development methodology and our RT-middleware concepts are discussed. The RT-component, which is a basic software unit of RT-middleware based system integration, is derived from this discussion. A methodology of system development by using RT-components, and a framework for component development are proposed. Evaluations of some RT-component based systems are performed. Finally, conclusions and future work is described.

474 citations

Journal ArticleDOI
TL;DR: To minimize prosthesis cost of transport and motor or transmission size, a parallel stiffness is selected that supplies the necessary ankle stiffness during early stance period dorsiflexion, eliminating the need for SEA during that gait phase.
Abstract: The minimum level of series compliance that adequately protects the transmission from damage during foot collision fails to satisfy bandwidth requirements. As a resolution to this difficulty, parallel motor elasticity is used to lower the forces borne by the SEA, enhancing system force bandwidth. To minimize prosthesis cost of transport (COT) and motor or transmission size, we select a parallel stiffness that supplies the necessary ankle stiffness during early stance period dorsiflexion, eliminating the need for SEA during that gait phase. In future investigations, we hope to apply the ankle-foot design to robotic, orthotic, and exoskeletal applications. In the design of biomimetic ankle-foot systems, we feel both series and parallel motor elasticity are of paramount importance.

393 citations