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Nishi-Tokyo-shi, Japan

Yamamoto K.,Tokyo Technology | Nakamura Y.,University of Tokyo
Proceedings - IEEE International Conference on Robotics and Automation | Year: 2010

Humanoid robots should be able to stand and walk in the presence of external disturbances. This paper addresses the robustness of a humanoid robot to unknown disturbances. Applying the maximal CPI set, it becomes possible to consider the physical constraint explicitly in the COG-ZMP inverted pendulum model control. In our previous research, the convergence speed of COG was improved by applying the switching control based on the maximal CPI set to the stabilization control assuming the contact region is constant. This paper presents updating calculation method of the maximal CPI set when the contact region changes, and the authors propose a falling avoidance control as an application of it. Detecting the stepping necessity based on the maximal CPI set enables to unify the upright position stabilization and stepping motion for falling avoidance. The validity of the proposed method is verified with experiments. ©2010 IEEE. Source

Yamamoto K.,EcoTopia Science Institute | Okada M.,Tokyo Technology
Proceedings of the SICE Annual Conference | Year: 2013

There are a lot of pedestrian flows in the commercial facility. These flows often cross each other, and change goals, e.g. reception desk or ticket-vending machine. Moreover, too long people queue at a goal sometimes blocks up other flows and makes us uncomfortable. In order to reduce the congestion and realize the amenity space the environmental design considering the swarm behavior of people is required. In this paper, the authors focus on the formation control of people queue at a goal and propose the formation control method by optimizing the layout of movable partitions. The effectiveness of the proposed method is verified with simulations. Source

Satoh D.,Tokyo Technology | Yoshida M.,High Energy Accelerator Research Organization | Natsui T.,High Energy Accelerator Research Organization | Hayashizaki N.,RLNR
IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference | Year: 2014

We have been developing a novel photocathode RF gun system with an advanced RF cavity structure and a new photocathode material for the SuperKEKB electron linac. This injector is required to obtain a low emittance and high charge electron beams in order to achieve the highest luminosity in the world. The required beam parameters are 5 nC and 20 mm-mrad from the RF gun. Moreover, 10 nC electron beams for positron production will be also generated by the same RF gun. In order to obtain extremely high charge electron beams, Yb-based laser system is being upgraded for higher power and a high temperature photocathode system for a quantum efficiency (QE) enhancement will be introduced to the new RF gun system. This paper reports on the research and development of the system of high temperature photocathode for QE enhancement to be able to generate high charge electron beams (∼10 nC) at the RF gun in SuperKEKB electron linac. Copyright © 2014 CC-BY-3.0 and by the respective authors. Source

Okada M.,Tokyo Technology | Takeishi J.,Tokyo Technology
IEEE/RSJ 2010 International Conference on Intelligent Robots and Systems, IROS 2010 - Conference Proceedings | Year: 2010

To prevent the human injury or breakage of the robot caused by interaction or collision with the robot and its environment, it is an important issue to introduce robot softness. However, because not only softness but also stiffness is required for precise task execution, the simultaneous realization of softness and stiffness using time varying stiffness is required in the real environment. We focus on the robot motion, and propose a realization method of time varying stiffness using robot motion and nonlinear passive stiffness. To realize the purpose-designed property of the time dependent stiffness, the nonlinear property of the passive stiffness has to be arbitrary designed considering the robot dynamics. In this paper, we propose the nonlinear property design method of passive stiffness based on kineto-statics with closed kinematic chain. The mechanism is synthesized based on the optimization of the generative force or torque, and purpose-designed stiffness is realized. The proposed method is evaluated by simulations and experiments using the prototype of the landing mechanism. ©2010 IEEE. Source

Okada M.,Tokyo Technology | Watanabe M.,Tokyo Technology
IEEE/RSJ 2010 International Conference on Intelligent Robots and Systems, IROS 2010 - Conference Proceedings | Year: 2010

Skill or motion transfer from someone to other persons is always required for dance teaching, rehabilitation, sports and so on. For teaching or transfer of motion, a dance notation and display of sequence of motion are often used effectively. However, these contain only the instantaneous postures of motion or professional subjective sense, it is not easy for beginners to understand the dynamical knack of motion. In this paper, we propose "pseudo- reference" that is a virtual target posture in the human motion. The pseudoreference is developed based on the modeling of the human motion by the attractor design method which realizes an autonomous system. By comparing the nonlinear controller with conventional control systems (1DOF and 2DOF control system), the pseudo-reference is obtained as an embodiment of the implicit reference. The proposed method is performed with the inverted pendulum system and the tap dancing robot, and the validity and feasibility for motion transfer of the pseudo-reference are evaluated. ©2010 IEEE. Source

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