A Novel Two Degrees of Freedom Rotational Decoupled Parallel Mechanism

In the field of spatial orientation, the rotational parallel mechanism is widely used. While the existence of coupling brings about the parallel mechanism some difficulties in kinematics and dynamic analysis, the development of control system, and so on. This condition restricts the application fields and effects of the rotational parallel mechanism. Therefore, this paper proposes a novel 2-DOF (two degrees of freedom) rotational DPM (decoupled parallel mechanism). The feature of the mechanism is described and their movement form is analyzed with screw theory. The proposition of the novel rotational DPM will enrich the configurations of the parallel mechanism, and the contents of this paper should be useful for the further research and application of the rotational parallel mechanism.

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The Nonexistence of Three Degrees of Freedom Rotational Fully Decoupled Parallel Mechanism

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.284-287.1951 ◽

2013 ◽

Vol 284-287 ◽

pp. 1951-1955 ◽

Cited By ~ 1

Author(s):

Yu Lei Hou ◽

Da Xing Zeng ◽

Yan Bin Duan ◽

Yong Sheng Zhao

Keyword(s):

Control System ◽

Parallel Mechanism ◽

Degrees Of Freedom ◽

Screw Theory ◽

Structure Design ◽

Theoretical Significance ◽

Moving Platform ◽

Configuration Synthesis ◽

Three Degrees Of Freedom ◽

Serial Mechanism

The existence of coupling makes the parallel mechanism possess some special advantages over the serial mechanism, while it is just the coupling that brings about the parallel mechanism some difficulties in kinematics and dynamic analysis, the development of control system, and the trajectory planning. Therefore the research on the decoupled parallel mechanism becomes one of the hot of the mechanism fields. While whether the parallel mechanism can realize decouple is the premise for synthesis and analysis of the parallel mechanism. Based on screw theory, the existence of the three degrees of freedom (3-DoF) rotational fully-decoupled parallel mechanism is distinguished. Then taking the 6-PUS/UPU parallel mechanism as example, the rotation angles of the moving platform are measured, which is verified the impossibility of the 3-DoF rotation decoupling. The contents of this paper should possess theoretical significance for the innovative configuration synthesis and structure design of rotational decoupled parallel mechanism.

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Research on Kinematics and Pouring Law of a Mobile Heavy Load Pouring Robot

Mathematical Problems in Engineering ◽

10.1155/2018/8790575 ◽

2018 ◽

Vol 2018 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Long Li ◽

Chengjun Wang ◽

Hongtao Wu

Keyword(s):

Parallel Mechanism ◽

Degrees Of Freedom ◽

Position Control ◽

Screw Theory ◽

Great Influence ◽

Inverse Kinematic ◽

The Novel ◽

Heavy Load ◽

Motion Characteristics ◽

The Relationship

In order to meet the requirement of continuous pouring in many varieties and small batches in casting production, a mobile heavy load pouring robot is developed based on a new 4-UPU parallel mechanism due to its strong carrying capacity. Firstly, the instantaneous motion characteristics of the novel 4-UPU parallel mechanism with four degrees of freedom (DOF) are analyzed using screw theory. By using the geometric method, both the forward and inverse kinematic solutions of the proposed robot system are given out. Secondly, based on a common pouring ladle, the volume change of pouring liquid in pouring process and the relationship between tilting angular velocity and flow rate are analyzed, and the results show that the shape of the ladle and the design of the pouring mouth have great influence on the tilting model. It is an important basis for the division of the sectional model. Finally, a numerical example is given to verify the effectiveness of the developed tilting model. The mapping relation between the tilting model and the parallel mechanism shows that the pouring flow can be adjusted by controlling the movement of parallel manipulator. The research of this paper provides an important theoretical basis for the position control of mobile heavy load pouring robot and the research of pouring speed control.

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Design of subordinate control system with two degrees of freedom

Power Engineering, Control and Information Technologies in Geotechnical Systems ◽

10.1201/b18475-25 ◽

2015 ◽

pp. 185-194 ◽

Cited By ~ 1

Author(s):

V. Sosedka ◽

R. Mazur ◽

M. Isakova

Keyword(s):

Control System ◽

Degrees Of Freedom ◽

Two Degrees Of Freedom

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A Flexible Transoral Robot Towards COVID-19 Swab Sampling

Frontiers in Robotics and AI ◽

10.3389/frobt.2021.612167 ◽

2021 ◽

Vol 8 ◽

Author(s):

Changsheng Li ◽

Xiaoyi Gu ◽

Xiao Xiao ◽

Chwee Ming Lim ◽

Xingguang Duan ◽

...

Keyword(s):

Parallel Mechanism ◽

Degrees Of Freedom ◽

Flexible Manipulator ◽

The Novel ◽

Visual Guidance ◽

Face To Face ◽

Tongue Depressor ◽

Operation Procedure ◽

The Face ◽

Master Device

There are high risks of infection for surgeons during the face-to-face COVID-19 swab sampling due to the novel coronavirus’s infectivity. To address this issue, we propose a flexible transoral robot with a teleoperated configuration for swab sampling. The robot comprises a flexible manipulator, an endoscope with a monitor, and a master device. A 3-prismatic-universal (3-PU) flexible parallel mechanism with 3 degrees of freedom (DOF) is used to realize the manipulator’s movements. The flexibility of the manipulator improves the safety of testees. Besides, the master device is similar to the manipulator in structure. It is easy to use for operators. Under the guidance of the vision from the endoscope, the surgeon can operate the master device to control the swab’s motion attached to the manipulator for sampling. In this paper, the robotic system, the workspace, and the operation procedure are described in detail. The tongue depressor, which is used to prevent the tongue’s interference during the sampling, is also tested. The accuracy of the manipulator under visual guidance is validated intuitively. Finally, the experiment on a human phantom is conducted to demonstrate the feasibility of the robot preliminarily.

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