The Kinematic Modeling of a 2-DOF Rotational Parallel Fixture

2012 ◽  
Vol 605-607 ◽  
pp. 1465-1468
Author(s):  
Shan Le Cai ◽  
Wen Tao Huang ◽  
Li Bin Peng
Keyword(s):  
Degrees Of Freedom ◽  
Institutional Analysis ◽  
Modeling Method ◽  
Degree Of Freedom ◽  
Kinematic Modeling ◽  
Kinematics Modeling ◽  
Inverse Solutions ◽  
Rotational Degrees Of Freedom ◽  
Moving Platform

Put forward a kind of 2 dof parallel fixture. The moving platform of the fixture has two rotational degrees of freedom relative to the fixed platform. Do the institutional analysis and its degree of freedom calculation. Study the kinematics modeling method, and carry out an analysis on forward and inverse solutions of its positions. The new parallel fixture will have wide appli¬ca¬tion in the field of machining.

scholarly journals Kinematics modeling of a two DOFs continuum manipulator with uniform notches

2020 ◽  
Vol 309 ◽  
pp. 05006
Author(s):  
Xiaolong Wang ◽  
Haodong Wang ◽  
Zhijiang Du ◽  
Wenlong Yang
Keyword(s):  
Friction Coefficient ◽  
Degrees Of Freedom ◽  
Elliptic Integral ◽  
Load Capacity ◽  
Kinematic Model ◽  
Kinematic Modeling ◽  
Flexible Beams ◽  
Kinematics Modeling ◽  
Single Port Laparoscopy ◽  
Continuum Manipulator

Continuum manipulators have been widely adopted for single-port laparoscopy (SPL). A novel continuum manipulator with uniform notches which has two degrees of freedom (DOFs) is presented in this paper. The arrangement of flexible beams makes it own a higher load capacity. Its kinematic model is coupled with the mechanical model. The comprehensive elliptic integral solution (CEIS) is more practical in the actual deformation of the flexible beams. Based on that method, kinematics modeling is established from the driven space to the Cartesian space. The friction coefficient is an important factor which can affect the kinematic modeling. Therefore, an experimental platform is established to obtain the friction coefficient. The kinematic modeling is verified through the prototype. Experimental results show that the model has high precision.

scholarly journals A New Metamorphic Parallel Leg Mechanism with Reconfigurable Moving Platform

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yong Xu ◽  
Zheng Liang ◽  
Jiali Liu
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Screw Theory ◽  
Degree Of Freedom ◽  
Walking Robots ◽  
Metamorphic Mechanism ◽  
Parallel Leg Mechanism ◽  
Moving Platform ◽  
Configuration Synthesis

This paper proposes the concept of full configuration state of metamorphic mechanism. Based on the concept, the configuration synthesis principle of metamorphic parallel mechanism is put forward. Firstly, a metamorphic parallel mechanism in full configuration state is synthesized, and then full configuration state evolves into a specific configuration state by increasing constraints or decreasing degrees of freedom. A reconfigurable moving platform based on the triple symmetric Bricard spatial closed-loop mechanism with a single degree of freedom is proposed. Based on this, a new method for switching motion configuration states of the metamorphic parallel mechanism is constructed. According to the configuration synthesis principle presented above, a novel metamorphic parallel mechanism that can switch between three- and four-degree-of-freedom is synthesized, and then the triple symmetric Bricard spatial closed-loop mechanism is used as the reconfigurable moving platform (that is, the reconfigurable foot of a walking robot) of the metamorphic mechanism, and thus, a novel metamorphic parallel leg mechanism is created. The screw theory is used to verify the degrees of freedom of the new type of metamorphic parallel leg. The proposed metamorphic parallel leg mechanism is expected to improve flexibility and adaptability of walking robots in unstructured environment.

scholarly journals Design and analysis of a class of redundant collaborative manipulators with 2D large rotational angles

2019 ◽  
Vol 15 (1) ◽  
pp. 66-80
Author(s):  
Xiaodong Jin ◽  
Yuefa Fang ◽  
Dan Zhang ◽  
Xueling Luo
Keyword(s):  
Machine Tools ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
Rotational Axis ◽  
Revolute Joints ◽  
3D Printers ◽  
Rotational Degrees Of Freedom ◽  
Moving Platform ◽  
Orientation Workspace

AbstractThe parallel spindle heads with high rotational capability are demanded in the area of multi-axis machine tools and 3D printers. This paper focuses on designing a class of 2R1T (R: Rotation; T: Translation) parallel spindle heads and the corresponding collaborative 5-axis manipulators with 2-dimension (2D) large rotational angles. In order to construct 2D rotational degrees of freedom (DOFs), a platform with 2D revolute joints is proposed first. Based on the constraint screw theory, the feasible limbs that can be connected in the platform are synthesized. In order to provide constant rotational axis for the platform, a class of redundant limbs are designed. A class of redundant 2R1T parallel spindle heads is obtained by connecting the redundant limbs with the platform and the redundant characteristics are verified by the modified Grübler-Kutzbach criterion. The corresponding 5-axis collaborative manipulators are presented by constructing a 2-DOF series translational bottom moving platform. The inverse kinematics and the orientation workspace as well as the decoupling characteristics of this type of 2R1T parallel spindle heads are analyzed. The results show that these manipulators have large 2D rotational angles than the traditional A3/Z3 heads and can be potentially used in the application of multi-axis machine tools and the 3D printers.

Structural synthesis of a class of 3-DOF wrist mechanisms with redundantly-actuated closed-loop units

2015 ◽  
Vol 230 (2) ◽  
pp. 276-290 ◽  
Author(s):  
Haibo Qu ◽  
Yuefa Fang ◽  
Sheng Guo
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Screw Theory ◽  
Open Loop ◽  
Structural Synthesis ◽  
Constraint System ◽  
Redundantly Actuated ◽  
Rotational Degrees Of Freedom ◽  
Moving Platform

In this paper, a new method is proposed for the structural synthesis of a class of redundantly-actuated parallel wrists (RaPWs) with three rotational degrees of freedom of the moving platform and symmetrical structures based on screw theory. First, the new procedure for structural synthesis of RaPWs with closed-loop actuated unit is proposed and the constraint system of the moving platform of RaPWs is analyzed. Then, considering the inclusion relation between the primary constraint system and the limb constraint system, the type of kinematic limb is determined. The synthesis of type-1 and type-2 kinematic limbs is dealt with based on the obtained closed-loop actuated unit and open-loop sub-limb. Next, the RaPWs are synthesized and a number of new RaPWs have been identified. Finally, the condition for proper actuator selections of RaPWs is revealed, and one example is used to perform the validation.

Structural Synthesis of a Class of Five-DOF Parallel Robot Mechanisms Based on Single-Opened-Chain Units

2001 ◽  
Author(s):  
Qiong Jin ◽  
Ting-Li Yang ◽  
An-Xin Liu ◽  
Hui-Ping Shen ◽  
Fang-Hua Yao
Keyword(s):  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Degree Of Freedom ◽  
Structural Synthesis ◽  
Structure Synthesis ◽  
Systematic Methodology ◽  
Rotational Degrees Of Freedom ◽  
Topological Characteristics

Abstract Based on the units of single-opened-chain limb, some topological characteristics of rank-degenerate parallel robot mechanisms are revealed, and a systematic methodology for the structural synthesis of a class of five degree-of-freedom parallel robot mechanisms is put forward in this paper. 49 new mechanisms with three translational and two rotational degrees of freedom are synthesized and classified. The method proposed in this paper is of universal significance and has been used for the structure synthesis of rank-degenerate parallel robot mechanisms with other kinematics output types.

An Improved Kinematic Model for Robots and Spatial Mechanisms: Part I — Model Development

1991 ◽  
Author(s):  
Ibrahim Niyazi Bodur
Keyword(s):  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Model Development ◽  
Kinematic Chain ◽  
Degree Of Freedom ◽  
Kinematic Modeling ◽  
Coordinate Frames ◽  
Six Degrees Of Freedom ◽  
Transformation Matrices ◽  
Relative Coordinate

Abstract In this paper an improved kinematic modeling method is developed which is applicable to both open and closed kinematic chain topology mechanisms. This methodology is based on relative coordinate frames assigned to the individual links and joints, and the 4 × 4 homogenous transformation matrices between these relative coordinate frames. The homogenous transformation matrices can accommodate the full six degrees-of-freedom necessary in 3-D space. Therefore, this method enables one to develop a kinematic model that corresponds to the actual mechanism. In doing so, the effect of the links and joints are considered separately which will aid one in conceptual and actual development of the model. The method is applied to a Cincinnati-Milacron T3 robot which is a six degree-of-freedom robot with a 3-D spatial serial configuration mechanism made of binary links and one degree-of-freedom joints connecting the links. The results obtained from the methodology developed here are compared to the results of a popular method developed by another researcher. The methodology developed in this paper is applicable to higher degree-of-freedom joints, up to the full six degrees-of-freedom. It can also be applied to multi-loop mechanisms with the accompanying increase in the complexity of the model. This method helps to reduce the complexity of the problem when one uses the kinematic model of a mechanism in an interference checking, dynamic modeling and simulation, and link flexibility problem. Finally, it is shown that the use of 4 × 4 homogenous transformation matrices do not increase the calculational complexity of the problem appreciably.

Duct Cleaning Robot Comprehensive Kinematics Modeling and Analysis Considering the Complex Terrain

2012 ◽  
Vol 430-432 ◽  
pp. 2032-2036 ◽  
Author(s):  
Bao Qiang Wu ◽  
Wei Sun ◽  
Ming Hua Ouyang
Keyword(s):  
Complex Terrain ◽  
Kinematic Model ◽  
Modeling Method ◽  
Kinematic Modeling ◽  
Motion Modeling ◽  
Modeling And Analysis ◽  
Robot Trajectory ◽  
Cleaning Robot ◽  
Kinematics Modeling ◽  
Duct Cleaning Robot

Complex terrain conditions greatly influences the movement of mobile robot,which should not be neglected.In this paper,a novel motion modeling idea is proposed, in which the robot chassis attitude angle changes caused by topographic changes was real-timely measured and be input into the robot kinematic modeling process to establish the overall kinematic model of robot. This modeling method reflect the various parts of the robot motion relations, and also display the complex topography of the robot trajectory of the end of the actuator.Finally,validated and analyzed the feasibility of the modeling method.

On the Use of Quantum Thermal Bath in Unimolecular Fragmentation Simulations

2019 ◽  
Author(s):  
Riccardo Spezia ◽  
Hichem Dammak
Keyword(s):  
Degrees Of Freedom ◽  
Molecular Simulations ◽  
Zero Point ◽  
Thermal Bath ◽  
Unimolecular Dissociation ◽  
Point Energy ◽  
Rotational Degrees Of Freedom ◽  
The Difference ◽  
Nuclear Effects

<div> <div> <div> <p>In the present work we have investigated the possibility of using the Quantum Thermal Bath (QTB) method in molecular simulations of unimolecular dissociation processes. Notably, QTB is aimed in introducing quantum nuclear effects with a com- putational time which is basically the same as in newtonian simulations. At this end we have considered the model fragmentation of CH4 for which an analytical function is present in the literature. Moreover, based on the same model a microcanonical algorithm which monitor zero-point energy of products, and eventually modifies tra- jectories, was recently proposed. We have thus compared classical and quantum rate constant with these different models. QTB seems to correctly reproduce some quantum features, in particular the difference between classical and quantum activation energies, making it a promising method to study unimolecular fragmentation of much complex systems with molecular simulations. The role of QTB thermostat on rotational degrees of freedom is also analyzed and discussed. </p> </div> </div> </div>

scholarly journals Design and Calibration of a Hall Effect System for Measurement of Six-Degree-of-Freedom Motion within a Stacked Column

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3740
Author(s):  
Olafur Oddbjornsson ◽  
Panos Kloukinas ◽  
Tansu Gokce ◽  
Kate Bourne ◽  
Tony Horseman ◽  
...  
Keyword(s):  
Hall Effect ◽  
Degrees Of Freedom ◽  
Reactor Core ◽  
Degree Of Freedom ◽  
Life Extension ◽  
Scale Model ◽  
Design Development ◽  
Seismic Safety ◽  
Six Degrees Of Freedom ◽  
Six Degree Of Freedom

This paper presents the design, development and evaluation of a unique non-contact instrumentation system that can accurately measure the interface displacement between two rigid components in six degrees of freedom. The system was developed to allow measurement of the relative displacements between interfaces within a stacked column of brick-like components, with an accuracy of 0.05 mm and 0.1 degrees. The columns comprised up to 14 components, with each component being a scale model of a graphite brick within an Advanced Gas-cooled Reactor core. A set of 585 of these columns makes up the Multi Layer Array, which was designed to investigate the response of the reactor core to seismic inputs, with excitation levels up to 1 g from 0 to 100 Hz. The nature of the application required a compact and robust design capable of accurately recording fully coupled motion in all six degrees of freedom during dynamic testing. The novel design implemented 12 Hall effect sensors with a calibration procedure based on system identification techniques. The measurement uncertainty was ±0.050 mm for displacement and ±0.052 degrees for rotation, and the system can tolerate loss of data from two sensors with the uncertainly increasing to only 0.061 mm in translation and 0.088 degrees in rotation. The system has been deployed in a research programme that has enabled EDF to present seismic safety cases to the Office for Nuclear Regulation, resulting in life extension approvals for several reactors. The measurement system developed could be readily applied to other situations where the imposed level of stress at the interface causes negligible material strain, and accurate non-contact six-degree-of-freedom interface measurement is required.

Sign in / Sign up

Export Citation Format

Share Document