Master Device With Bending Safety for Flexible Surgical Robots

Abstract Flexible robots have been widely studied for application to minimally invasive surgery because of their dexterity and miniaturization ability. Conventional master devices developed to manipulate rigid link-type robots are difficult to apply to flexible robots due to structural difference. In addition, the different kinematic structures of the master device and flexible slave robot cause complex mapping issues. Furthermore, most high-redundancy flexible robots inserted through an over-tube have limited bending angles depending on the insertion depth. Conventional master devices were not designed to comply with this limitation of flexible robots. We developed an isosceles master device that provides intuitive and simple mapping factors for controlling and maintaining the wire tension of a flexible robot in a safe range. We applied a variable isosceles triangle mechanism that structurally limits the bending angle according to the insertion depth. Experimental results showed that our master device can control a flexible slave robot with an error of less than 1.5 mm. Because of the limited bending angle, excessive tension and the resulting damage to the wire were prevented. The isosceles master device can also hold its position and orientation with a passive holding mechanism.

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Design Process of High Dynamics Multi-Link Flexible Robot Manipulators

Volume 5A: 41st Mechanisms and Robotics Conference ◽

10.1115/detc2017-67721 ◽

2017 ◽

Author(s):

Thomas Solatges ◽

Mathieu Rognant ◽

Sébastien Rubrecht ◽

Eric Courteille ◽

Philippe Bidaud

Keyword(s):

Design Process ◽

Performance Indicators ◽

Robot Manipulators ◽

Experimental Results ◽

Control Architecture ◽

Flexible Robot ◽

Flexible Robots ◽

Modeling Tool ◽

And Performance ◽

High Dynamics

This paper presents a design process based on an advanced flexible robots modeling tool associated with realistic actuators models and pre-defined control architecture. This process implements dedicated feasibility and performance indicators, which are used to evaluate a design and its sensitivity on the considered parameters. The proposed approach is illustrated with theoretical and experimental results obtained with the YAKA robot.

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1501 Development of Flexible Robot Arm with Non-contact Type Bending Angle Sensor and Its Application

The Proceedings of Conference of Chugoku-Shikoku Branch ◽

10.1299/jsmecs.2009.47.513 ◽

2009 ◽

Vol 2009.47 (0) ◽

pp. 513-514

Author(s):

Kyohei SATO ◽

Shujiro DOHTA ◽

Tetsuya AKAGI

Keyword(s):

Robot Arm ◽

Flexible Robot ◽

Angle Sensor ◽

Bending Angle ◽

Contact Type

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Dynamics and Motion Control of Flexible Manipulators With Multi-Degree of Kinematic Redundancy

Volume 7: 29th Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2005-84160 ◽

2005 ◽

Author(s):

Yue-Qing Yu ◽

Ji-Yun Yang

Keyword(s):

Motion Control ◽

Robot Manipulator ◽

Robot Manipulators ◽

Flexible Manipulator ◽

Flexible Manipulators ◽

Kinematic Redundancy ◽

Flexible Robot ◽

Flexible Robots ◽

Dynamic Performances ◽

Self Motion

The dynamics and motion control of flexible robot manipulators is an advanced topic in the study of robotics. The precise tracking of the end-effector trajectory of flexible robots can be improved by the self-motion of redundant manipulators. The flexible manipulator with single-degree of kinematic redundancy has been considered only at present. This study addresses on the dynamics and motion control of flexible robots with multi-degree of kinematic redundancy. Compared with the robot with one-degree of redundancy, the optimal motion programming of a flexible robot manipulator with two-degree of redundancy has been obtained successfully based on pseudo-inverse solution. The numerical results of planar three-link and four-link flexible manipulators show the advantage of multi-degree of redundancy in improving the kinematic and dynamic performances of flexible robot manipulators.

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New development of the dynamic modeling and the inverse dynamic analysis for flexible robot

International Journal of Advanced Robotic Systems ◽

10.1177/1729881420943341 ◽

2020 ◽

Vol 17 (4) ◽

pp. 172988142094334

Author(s):

Chu A My ◽

Duong X Bien

Keyword(s):

Dynamic Analysis ◽

Dynamic Modeling ◽

Bisection Method ◽

Flexible Robot ◽

Inverse Dynamic ◽

Flexible Robots ◽

Prismatic Joint ◽

Inverse Dynamic Analysis ◽

New Development ◽

Prismatic Joints

When a segment of a flexible link of a flexible robot is currently sliding through a prismatic joint, it is usually assumed that the elastic deformation of the segment equals to zero. This is a kind of time-dependent boundary condition when formulating the dynamics model of a flexible robot consisting of prismatic joints. Hence, the dynamic modeling and especially the inverse dynamic analysis of the flexible robots with the prismatic joints are challenging. In this article, we present a new development of the dynamic modeling method for a generic two-link flexible robot that consists of a prismatic joint and a revolute joint. Moreover, a new bisection method-based algorithm is proposed to analyze the inverse dynamic responses of the flexible robots. Since the bisection method is a rapid converging method in mathematics, the proposed algorithm is effectively applicable to solving the inverse dynamic problem of a flexible robot in a robust manner. Last, the numerical simulation results show the effectiveness and the robustness of the proposed method.

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Incorporation of Joint Flexibility With Link Flexibility: Dynamic Modeling and Analysis

Volume 3C: 15th Biennial Conference on Mechanical Vibration and Noise — Vibration Control, Analysis, and Identification ◽

10.1115/detc1995-0713 ◽

1995 ◽

Author(s):

Degao Li ◽

Jean W. Zu ◽

Andrew A. Goldenberg

Keyword(s):

Dynamic Modeling ◽

Mode Analysis ◽

Mode Shapes ◽

Flexible Robot ◽

Flexible Robots ◽

Flexible Joint ◽

Joint Flexibility ◽

Modeling And Analysis ◽

Assumed Mode Method ◽

Link Flexibility

Abstract Flexible robots with both link flexibility and joint flexibility have received increasing attention recently. In modeling the flexible robots with the assumed mode method, the model accuracy is highly dependent on the mode shapes of the link deflection. For flexible-link, flexible-joint robots, conventionally used clamped-free or pinned-free modes may cause large errors. To address this problem, this paper presents a systematic approach to dynamic modeling and mode analysis of a single-link flexible robot, which has a flexible joint and a hub at the base end and a payload at the free end. Accurate modes of the system are obtained. The following important conclusions are obtained: (1) Even a small joint flexibility can significantly affect the system frequencies; (2) The fundamental frequency is sensitive to the change in the payload and is not sensitive to the change in the hub inertia.

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Enhancement of Vibration Suppression for Multi-Link Flexible Robots Using Direct Parameter Adaptation

10.1115/imece2001/dsc-24607 ◽

2001 ◽

Author(s):

Joono Cheong ◽

Wan Kyun Chung ◽

Youngil Youm

Keyword(s):

Adaptive Control ◽

Vibration Suppression ◽

Simplified Model ◽

Robot Dynamics ◽

Flexible Robot ◽

Parameter Mismatch ◽

Parameter Adaptation ◽

Flexible Robots ◽

Control Schemes ◽

On Line

Abstract The precise modeling of multi-link flexible robot is hard to obtain and even if we can get it, it is difficult to use in on-line control tasks. Due to these reasons, a simplified model is often used to describe the robot dynamics instead of using complex dynamic model. In the simplified model, however, parameter mismatch and structural modeling error are inevitable. To compensate these uncertainties, an adaptive control is formulated in this paper after separating the system into rigid and flexible subsystems. A simple direct parameter update rule is presented considering the flexible subsystem. Different from most of adaptive control schemes in multi-link flexible robots, which is indirect model-independent approach, the proposed adaptive control is a direct one and good for fast suppression of vibration of uncertain and untuned systems. We verify the effectiveness of the proposed algorithm through experiments.

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An Energy Analyser for Contrast Enhancement in STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052183 ◽

1974 ◽

Vol 32 ◽

pp. 434-435

Author(s):

H.T. Pearce-Percy

Keyword(s):

Contrast Enhancement ◽

Bending Angle ◽

Magnetic Sector ◽

Conventional Design ◽

Bending Radius ◽

Sector Type

Recently an energy analyser of the uniform magnetic sector type has been installd in a 100KV microscope. This microscope can be used in the STEM mode. The sector is of conventional design (Fig. 1). The bending angle was chosen to be 90° for ease of construction. The bending radius (ρ) is 20 cm. and the object and image distances are 42.5 cm. and 30.0 cm. respectively.

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Microstructural Development in Nb-Ti Multifilamentary Superconductors During Processing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100117911 ◽

1985 ◽

Vol 43 ◽

pp. 190-191

Author(s):

A. W. West

Keyword(s):

Heat Treatment ◽

Critical Current Density ◽

Copper Matrix ◽

Wire Drawing ◽

Heat Treatments ◽

Microstructural Development ◽

Final Size ◽

Density Values ◽

The Wire ◽

Multifilamentary Superconductors

The influence of the filament microstructure on the critical current density values, Jc, of Nb-Ti multifilamentary superconducting composites has been well documented. However the development of these microstructures during composite processing is still under investigation.During manufacture, the multifilamentary composite is given several heat treatments interspersed in the wire-drawing schedule. Typically, these heat treatments are for 5 to 80 hours at temperatures between 523 and 573K. A short heat treatment of approximately 3 hours at 573K is usually given to the wire at final size. Originally this heat treatment was given to soften the copper matrix, but recent work has shown that it can markedly change both the Jc value and microstructure of the composite.

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