A Wide-Range Velocity Measurement Method for Motion Control

http://ieeexplore.ieee.org/search/wrapper.jsp?arnumber=4602710 | http://ieeexplore.ieee.org/search/wrapper.jsp?arnumber=4602710This paper discusses velocity measurement for motor drives with optical encoders. Although many methods on velocity measurement have been proposed, accurate measurement was not achieved in a high-speed range. This paper therefore proposes synchronous-measurement method (S method) that measures the velocity synchronized with the alteration of pulse numbers in each sampling period. Accurate velocity measurement is achieved in all speed ranges with this method. Furthermore, other velocity prediction methods are applicable in addition to the method. Simulation and experimental results verify the validity of the proposed method.textapplication/pdfjournal articl

Robust Acceleration Control Based on Acceleration Measurement Using Optical Encoder

The purpose of this study is to realize robust acceleration control using optical encoders. A quantization error of an optical encoder limits performance of the acceleration control. Hence, the study extends the premise of the S method, a high performance velocity measurement method, to acceleration measurement. The proposed method was shown to considerably improve the accuracy of acceleration measurements. High performance of acceleration control is realized due to the accurate measurement. Experimental results verify the validity of the proposed method.(c)2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.textconference pape

甲殻型触覚インタフェースに基づくコミュニケーション技術の開発

若手展開研究: カテゴリBtextapplication/pdfresearch repor

Development of Power Assist System for Caregiver by Muscle Suit

A "muscle suit" that will provide muscular support for the paralyzed or those otherwise unable to move unaided is being developed as a wearable robot. The muscle suit consists of a mechanical armor-type frame and McKibben artificial muscle. Using a new link mechanism for the shoulder joint which consists of two half-circle links with four universal joints in total mounted at both ends of each link, all motion for the upper limb has been realized. Applying the muscle suit to non-healthy people such as elderly people and/or disable one requires very high-level safety and usability, from the practical point of view. We then in the first place for the practical use, apply the muscle suit to the manual worker. In this paper, we introduce how we can apply the muscle suit for the manual worker.(c)2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.textconference pape

Development of an Active Walker as a New Orthosis

More than one million people have difficulty in walking at least in Japan. Many kinds of walker have been developing so far for gait training though, they are used by grasping the front and/or the back part of them in order to hold trunk. It makes forward tilting or backward tilting of the upper half of the body and comes to difficult to keep right posture for walking. Moreover there are few examples of an active walker which is used if people have no muscular force for walking. In order to solve these issues, we have been developing the active walker by using the Hart Walker (HW) which consists of double upright knee ankle foot orthosis and 4-wheeled carriage with a stem located in the center of the carriage. Since waist part of the orthosis is attached to the top of the stem, there is no risk for falling, it is possible to keep the right posture, and both hands becomes completely be free. McKibben artificial muscles are attached to HW in order to control walking motion as an active walker. By walking experiment using child-size doll with the same kind of joints human has and weight, it is confirmed that human-like gait is realized by the active walker developed.(c)2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.textconference pape

Mechanism of Attitude Control Device for Floating Object

This paper describes the new mechanism on attitude control device for unfixed objects. Flywheel is a common attitude control device on spacecraft that provides precise control at an easy rate. However, rapid response is hardly achieved since low reaction torque is available applying flywheel. The purpose in this paper is to improve the response of attitude control device with flywheel. Brake equipment is mounted on the flywheel in order to raise the maximum torque. Maximum torque is raised dramatically utilizing the braking torque to the attitude control. Twin drive system is applied to this attitude control device so that the braking torque works in both rotation directions. It also made possible to charge the omentum without any interference to attitude control. The prototype of the attitude control device is constructed in order to examine the performance of the proposed mechanism. Experimental results show that its response improved applying the suggested mechanism. The two actuators, an electric DC motor and a powder brake, were compared in detail. It was shown that powder brake can apply high torque without large power supply in any frequency.(c)2003 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.textconference pape

A Design Method of Decentralized Control System Applying System Connection

Decentralized control is a promising method for large scale systems. A critical design method for decentralized control systems is desirable for solving the complicated design problem. Simple and explicit controller design becomes available with the idea of “function.” However, the hierarchy based on the network structure may impose restrictions on controller design. At the same time, various kinds of exceptions such as faults, performance limits and so on may also impose restrictions. This paper proposes a method of the controller design under these restrictions. The concept of system connection is applied to derive the hierarchy. An exception is treated the same as a communication blackout. The hierarchy structure is intentionally manipulated to decide the priority order of the functions. The unified design for the system with the hierarchical structure and exceptions can be realized through this method.慶應義塾大学大学院理工学研究科　国際論文発表奨励賞受賞 ISIE Student Forum Paper First Prize受賞　 (c)2005 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.textconference pape

Position/Force Scaling of Function-based Bilateral Control System

This paper describes the method of a scaling control for bilateral control systems. We have already suggested the concept of function so that a controller design of decentralized control systems becomes simple and explicit. Our suggestion in this paper is about a position/force scaling control on a function-based bilateral control system. A conventional coordinate transformation is expanded and the idea of scaling matrix is introduced. Independent position and force scaling controls are achieved applying this scaling matrix. We develop the dynarnics of manipulators to show that the dynamics in scaled function coordinates are independent to each other. Experimental results show the high transparency bilateral control with the function-based controller on scaled function coordinates.(c)2004 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.textconference pape

A controller design method based on functionality

Robots are expected to expand their range of activities to human environment. Robots in human environment need redundancy for environmental adaptation. Furthermore, they have to automatically modify their controllers in response to varying conditions of the environment. Therefore, the authors have proposed a method to design a hyper-degrees-of-freedom (DOF) control system efficiently. The method decouples a large control system into small independent components called "function." Motion of the entire control system is expressed as superposition of multiple functions. Combination of some functions realizes many patterns of motion. Hence, various motions are realized with much smaller efforts on controller design. Additionally, the controller design is explicit since a controller and a function correspond directly. This paper expands the method to multi-DOF robots in 3-D space, since the conventional method was limited to a multirobot system in 1-D space. A new problem of interference among function-based systems occurs along with the expansion. A disturbance observer is applied on each actuator to eliminate the interference. Procedures of controller design under varying conditions are also shown. The proposed method is applied to a grasping manipulator with 18 DOE Its experimental results show the validity of the method.(c)2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.textapplication/pdfjournal articl

Global Step Planning of Dynamic Biped Locomotion Considering Obstacles

This paper concerns on footstep planning of a biped robot in an environment having some obstacles. Biped robot has an advantage to work in human surroundings: This is accomplished by its capability to walk over the obstacles. Though its foot placement should be discussed to step over obstacles, it is difficult because dynamic biped locomotion is a complex interaction system between CoG trajectory and stepping point. This complex system is solved by the term control method applying LlPM. It is able to adjust the walking stride and speed independently with this method. The collision detection can be achieved easily through modeling the obstacles to an off-limits on the horizontal plane. A stamp area is set in order to avoid the extreme stride alteration. Through these methods, the robot can prepare for the obstacle beforehand and select a series of footsteps that provides stable locomotion. A simulation result is shown to approve the validity of the proposed methods.(c)2002 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.textconference pape