Ryogo Kubo

Study and Demonstration of Sleep and Adaptive Link Rate Control Mechanisms for Energy Efficient 10G-EPON

This paper describes sleep and adaptive link rate (ALR) control functions to reduce the power consumption of optical network units (ONUs) in 10 Gb/s Ethernet passive optical network (10G-EPON) systems. A hybrid mechanism that includes both sleep and ALR control functions is proposed with a view to further improving the power-saving performance. The sleep control function switches the ONU mode, i.e., active or sleep, depending on the presence or absence of traffic. The ALR control function switches the downlink rates between an optical line terminal (OLT) and an ONU, i.e., 1 Gb/s or 10 Gb/s, depending on the quantity of traffic. The proposed hybrid mechanism offers effective power management of ONUs on the basis of the traffic conditions. The proposed hybrid mechanism is validated by a numerical simulation and an experiment.

Sleep and Adaptive Link Rate Control for Power Saving in 10G-EPON Systems

This paper proposes a novel power-saving mechanism for the 10 Gbit/s Ethernet passive optical network (10GEPON) systems that are currently being discussed in IEEE 802.3av. The proposed power-saving mechanism includes a sleep control function and an adaptive link rate (ALR) control function. The sleep control function switches the modes of optical network units (ONUs), i.e. active and sleep modes, depending on the presence or absence of traffic. The ALR control function switches the link rate between the optical line terminal (OLT) and an ONU, i.e. 1 Gbit/s or 10 Gbit/s, depending on the quantity of traffic. The proposed hybrid mechanism offers effective power management of ONUs on the basis of the traffic conditions. The proposed hybrid mechanism is validated by some numerical simulations.

An extraction method of environmental surface profile using planar end-effectors

It is very important for robots working in unknown environment to recognize surface profile of the environment. This paper presents an extraction method of environmental surface profile based on environmental modes. Contact condition between a planar end-effector and the environment is also determined by using active motion which is named groping motion of the end-effector. The extraction method utilizes discrete Fourier transform (DFT) matrices as matrices transforming into environmental modes. The proposed method can be applied to a planar end-effector whose shape is an arbitrary polygon. Moreover, a compliance controller for attitude of a planar end-effector with 3 supporting points is proposed to realize stable contact motion with unknown environment. The validity of the proposed method is shown by the experimental results

Flexible Controller Design of Bilateral Grasping Systems Based on a Multilateral Control Scheme

This paper describes a novel bilateral grasping control system including master-slave robots with different degree of freedom. The master and slave controllers are designed based on a multilateral control scheme. Decoupling design of force and position controllers is realized by mode transformation using the discrete Fourier transform matrices and a disturbance observer. In the proposed system, a human operator manipulates two master robots, and three slave robots grasp an object cooperatively. The proposed system makes it possible to grasp an object tightly in the slave side and to transmit feeling of grasping to a human operator vividly. The validity of the proposed method is shown by numerical and experimental results.

Mechanical Recognition of Unknown Environment Using Active/Passive Contact Motion

This paper presents a method to determine contact conditions between a planar end-effector and the environment, i.e., face-to-face, face-to-line, or face-to-point contact. First of all, two kinds of contact motion of a planar end-effector, i.e., passive and active contact motions, are described. A compliance controller is implemented to achieve the passive contact motion, and the ldquogroping motionrdquo is generated as the active contact motion. Then, novel robot-friendly expressions of the environment are proposed based on the concept of environmental modes. Discrete Fourier transform matrices are utilized as matrices transforming environmental information into environmental modes. In the experiments, a planar end-effector contacts with the environment with the passive and active contact motions, and the environmental data obtained from sensors are transformed into environmental modes. The profiles of the extracted environmental modes are utilized to determine the contact conditions. The validity of the proposed method is confirmed by the experimental results.

Convergence of WDM Access and Ubiquitous Antenna Architecture for Broadband Wireless Services

This paper proposes a novel network architecture for Giga-bit throughput in broad- band ubiquitous networks. A convergence of WDM access and RoF ubiquitous antenna archi- tecture can realize universality of remote base stations for various types of air interfaces and the scalabilities of WDM technologies are expected to improve the throughput in wireless service area covered by RoF-MIMO antenna. We discusse distribution of MIMO antenna, method of RoF MIMO signals over WDM PON, and conflgurations of center station and remote base stations.

Hybrid Control for Multiple Robots in Grasping and Manipulation

This paper presents a grasping/manipulating control method using mode transformation. Discrete Fourier transform (DFT) matrices are utilized as transformation matrices. In grasping/manipulating control systems, decomposition into grasping motion and manipulating motion remains a key problem. By means of the proposed method, the grasping controller and the manipulating controller can be designed independently as a grasping mode and a manipulating mode, respectively. The grasping mode indicates internal force control and the manipulating mode indicates position control of COG (center of gravity). Hence, hybrid position/force control is achieved in grasping and manipulating an object using multiple robots. The validity of the proposed method is shown by the numerical and experimental results

Transparency of Time Delayed Bilateral Teleoperation Systems with Communication Disturbance Observer

Time delay in bilateral teleoperation systems seriously deteriorates the performance and possibly affects the stability. A novel time delay compensation method based on the concept of network disturbance (ND) and communication disturbance observer (CDOB) has been proposed and the validity has been verified by simulation and experimental results so far. However the validity of the time delay compensation method on performance has not been analyzed. This paper presents analysis of the validity of the time delay compensation method on performance. The analysis is discussed based on performance index of bilateral teleoperation systems, transparency. The analytical results are verified by simulation results.

Bilateral control with different inertia based on modal decomposition

A bilateral control robot is one of the master-slave teleoperation robots. Consider two robots, a master robot is manipulated by human operators and a slave robot contacts remote environment. Decoupling of a force control and a position control in bilateral control is realized using the mode transformation i.e. a force controller in the common mode and a position controller in the differential mode. In conventional method, high transparency in a bilateral control is obtained when the inertia of the master and slave robots are equal. However, high transparency is not achieved when the inertia of the master and slave robots is different. Additionally, transparency goes down in the case of the bilateral control with scaling. Since the common mode and the differential mode interfere when the inertia and scaling of the master robot slave robots are different. In this paper, modal space disturbance observer (MSDOB) is proposed to solve these interferential problems. MSDOB is disturbance observer in the modal space and is implemented in each mode. MSDOB eliminates these interferences and modeling error in the modal space. In the results, decoupling of the force control and the position control is realized. Therefore, high transparency is achieved even if the inertia and the scaling of the master and slave robots are different. From the simulation and experimental results, the validity of the proposed method was confirmed.

A Bilateral Controller Design Method for Master-Slave Robots with Different DOF

In this paper, a bilateral controller for master-slave robots with different DOF (degrees of freedom) is designed based on concept of multilateral control. A multilateral control system is a kind of bilateral control systems, and it is composed of multi-master and multi-slave robots, e.g. two master robots and three slave robots. It is shown that multilateral control, including bilateral control, is realized by using mode transformation by DFT (discrete Fourier transform). In addition, decoupling of each mode and transparency for multilateral control are discussed. Moreover, multilateral control is applied to a bilateral grasping control system. In this system, a human operator manipulates two master robots, and three slave robots grasp an object cooperatively. The proposed system makes it possible to grasp an object tightly in the slave side and to transmit feeling of grasping to a human operator vividly. The validity of the proposed method is shown by the experimental results.