Friction identification using iterative learning for a one-DOF parallel wire-driven system

[abstFig src='/00280006/04.jpg' width='300' text='Two-degrees-of-freedom planar system using three wires' ] Parallel-wire driven system, a kind of parallel-link mechanism, employs flexible and light wires in place of rigid links. By applying kinematics to parallel-wire driven systems, we seek to obtain the relationship between the end-effector’s position and wire length. Kinematics usually approximates the wire-contacting point of the winding reel (or guiding pulley) in the actuator unit to be a fixed point. Similar kinematic approximations, however, are likely to cause errors in controlling the end-effector position. In this study, therefore, we attempt to evaluate end-effector positioning errors due to inverse kinematic approximations. As the first step, we analyze end-effector positioning errors in two-degrees-of-freedom planar system and propose two methods to evaluate the positioning errors. Then, we conduct two case studies where we compare the errors due to inverse kinematic approximations and effects of wire’s elastic elements in order to confirm effectiveness of the proposed methods for evaluating end-effector positioning errors.

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Torque estimation system for human leg in passive motion using parallel-wire driven mechanism and iterative learning control

2009 IEEE International Conference on Rehabilitation Robotics ◽

10.1109/icorr.2009.5209601 ◽

2009 ◽

Cited By ~ 2

Author(s):

Hitoshi Kino ◽

Kenichi Saisyo ◽

Yasuhiko Hatanaka ◽

Sadao Kawamura

Keyword(s):

Iterative Learning Control ◽

Learning Control ◽

Iterative Learning ◽

Parallel Wire ◽

Passive Motion ◽

Torque Estimation ◽

Estimation System

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Error Analysis by Kinetics for Parallel-Wire Driven System Using Approximated Inverse Kinematics

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2018.p0763 ◽

2018 ◽

Vol 30 (5) ◽

pp. 763-771

Author(s):

Hitoshi Kino ◽

Takumi Imamura ◽

Norimitsu Sakagami ◽

◽

Keyword(s):

Inverse Kinematics ◽

Degrees Of Freedom ◽

Control Method ◽

Target Object ◽

Planar System ◽

Positioning Control ◽

Parallel Wire ◽

Positioning Errors ◽

Driven System ◽

The Wire

Parallel-wire driven systems, which use light flexible wires in place of rigid links, control the position of a target object by controlling their wire lengths. In the kinematics for such a parallel-wire driven system, when the relationship between the end-effector position and the wire lengths is investigated, a fixed point for the wire-contacting point on the winding reel in the actuator (or guide pulley) is often approximated to simplify the calculation. The approximated kinematics however could lead to a number of positioning errors in the positioning control. This study proposes a framework for evaluating these positioning control errors by using approximated inverse kinematics. In view of the system dynamics, this study analyzes the positioning control errors for the control method in the wire-length coordinates. We discuss a case study on a two degrees-of-freedom planar system using three wires.

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Mechanism and Control of Parallel-Wire Driven System

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2015.p0599 ◽

2015 ◽

Vol 27 (6) ◽

pp. 599-607 ◽

Cited By ~ 7

Author(s):

Hitoshi Kino ◽

◽

Sadao Kawamura ◽

Keyword(s):

Robot Manipulators ◽

Parallel Mechanisms ◽

Serial Link ◽

Parallel Wire ◽

Link Mechanism ◽

Human Arm ◽

Driven System ◽

Parallel Link ◽

And Control ◽

Controlled Object

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00270006/01.jpg"" width=""300"" /> A parallel-wire driven system</div>Many of the conventional robot manipulators have a serial-link mechanism to imitate a human arm. In recent years, however, industries have been aggressive in putting parallel-link mechanisms into practical use to cope with various problems that no conventional serial-link mechanisms have ever been able to solve. Under the circumstances, this paper describes a parallel-wire driven system, one of the parallel mechanisms. It is a system to drive a controlled object with flexible and light wires instead of rigid links. It has many advantages over conventional serial-link mechanisms or other ordinary parallel-link mechanisms. This paper first overviews previous studies on parallel-wire driven robots, and then details the mechanism and control of these systems, as well as examples of their application.

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