A Spatial 3-DOF Translational Compliant Parallel Manipulator

2010 ◽  
Vol 34-35 ◽  
pp. 143-147 ◽  
Author(s):  
Da Chang Zhu ◽  
Yan Ping Feng
Keyword(s):  
Parallel Manipulator ◽  
Piezoelectric Actuators ◽  
Parallel Manipulators ◽  
Flexure Hinge ◽  
Cartesian Coordinate System ◽  
Optimal Method ◽  
New Approach ◽  
And Topology ◽  
Structure Synthesis ◽  
Cartesian Coordinate

A new approach of structure synthesis of 3-DoF compliant parallel manipulators with flexure hinge is proposed in this paper. Based on characteristics of flexure hinge and topology optimal method, the kinematics of the 3-DOF perpendicular compliant parallel manipulator with flexure hinge and its control system are developed. The parallel manipulator is driven by three piezoelectric actuators and the three actuators in this mechanism are arranged according to the Cartesian coordinate system. Experiments are conducted to give some validation of the theoretical analysis.

Structure Synthesis of 3-RRS Type Spatial Compliant Parallel Manipulator

2010 ◽  
Vol 44-47 ◽  
pp. 1375-1379
Author(s):  
Da Chang Zhu ◽  
Li Meng ◽  
Tao Jiang
Keyword(s):  
Parallel Manipulator ◽  
Compliant Mechanisms ◽  
Screw Theory ◽  
Weight Ratio ◽  
Parallel Manipulators ◽  
Robot System ◽  
New Approach ◽  
Structure Synthesis ◽  
Rigid Joints ◽  
Type 3

Parallel manipulators has been extensively studied by virtues or its high force-to-weight ratio and widely spread applications such as vehicle or flight simulator, a machine tool and the end effector of robot system. However, as each limb includes several rigid joints, assembling error is demanded strictly, especially in precision measurement and micro-electronics. On the other hand, compliant mechanisms take advantage of recoverable deformation to transfer or transform motion, force, or energy and the benefits of compliant mechanisms mainly come from the elimination of traditional rigid joints, but the traditional displacement method reduce the stiffness of spatial compliant parallel manipulators. In this paper, a new approach of structure synthesis of 3-DoF rotational compliant parallel manipulators is proposed. Based on screw theory, the structures of RRS type 3-DoF rotational spatial compliant parallel manipulator are developed. Experiments via ANSYS are conducted to give some validation of the theoretical analysis.

Workspace Analysis and Going through Singularities of 5-Bar Symmetric Planar Parallel Manipulator by Automated Selective Actuation Mechanism

2012 ◽  
Vol 588-589 ◽  
pp. 1664-1668
Author(s):  
Syam Sundar ◽  
Vijay S. Rathore ◽  
Manoj K. Sahi ◽  
V. Upendran ◽  
Anjan Kumar Dash
Keyword(s):  
Closed Form ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
New Approach ◽  
Serial Manipulators ◽  
Actuation Mechanism ◽  
Geometric Conditions ◽  
Workspace Analysis ◽  
Planar Parallel Manipulator ◽  
Planar Parallel Manipulators

In this article‚ a new approach is presented to determine the various shapes of workspaces of 5 bar symmetric planar parallel manipulators. Here the shape of the workspace is determined by the number of ways the workspaces of the two serial manipulators intersect with each other. Geometric conditions are established in each case and area of each shape of workspace is determined in closed form. Singularity is another important consideration in the design of parallel manipulators. In this paper, an approach is presented to go through the singularity points using an automatic selective actuation mechanism. A prototype 5-bar planar manipulator is fabricated along with an automatic selective actuation mechanism demonstrating the manipulator going through the singularity points.

Geometrical method to determine the reciprocal screws and applications to parallel manipulators

Robotica ◽  
2009 ◽  
Vol 27 (6) ◽  
pp. 929-940 ◽  
Author(s):  
Jianguo Zhao ◽  
Bing Li ◽  
Xiaojun Yang ◽  
Hongjian Yu
Keyword(s):  
Parallel Manipulator ◽  
Screw Theory ◽  
Parallel Manipulators ◽  
Singularity Analysis ◽  
Algebraic Manipulation ◽  
Robot Kinematics ◽  
Geometrical Approach ◽  
New Approach ◽  
Geometrical Relation ◽  
Manipulator Design

SUMMARYScrew theory has demonstrated its wide applications in robot kinematics and statics. We aim to propose an intuitive geometrical approach to obtain the reciprocal screws for a given screw system. Compared with the traditional Plücker coordinate method, the new approach is free from algebraic manipulation and can be used to obtain the reciprocal screws just by inspecting the structure of manipulator. The approach is based on three observations that describe the geometrical relation for zero pitch screw and infinite pitch screw. Based on the observations, the reciprocal screw systems of several common kinematic elements are analyzed, including usual kinematic pairs and chains. We also demonstrate usefulness of the geometrical approach by a variety of applications in mobility analysis, Jacobian formulation, and singularity analysis for parallel manipulator. This new approach can facilitate the parallel manipulator design process and provide sufficient insights for existing manipulators.

Type Synthesis of Uncoupled 2T2R Parallel Manipulators

2012 ◽  
Author(s):  
Yanbin Zhang ◽  
Kwun-lon Ting
Keyword(s):  
Parallel Manipulator ◽  
Screw Theory ◽  
Control Design ◽  
Parallel Manipulators ◽  
Velocity Space ◽  
Type Synthesis ◽  
Systematic Method ◽  
Structure Synthesis ◽  
Hybrid Manipulator ◽  
Actuated Joints

This paper presents a simple and systematic method for type synthesis of four-degree-of-freedom uncoupled parallel manipulators with two-translational and two-rotational (2T2R) motion components. Based on the concept of hybrid manipulator, one uncoupled 2T2R hybrid manipulator, which is composed of one full-isotropic planar 2T1R parallel manipulator and one revolute joint in serial assembly, is designed first. Then the structure synthesis of the fourth leg of 2T2R parallel manipulator is performed in terms of the reciprocal screw theory. Finally, the type synthesis of uncoupled 2T2R parallel manipulators is realized by combining the uncoupled 2T2R hybrid manipulator and one of the synthesized fourth legs. The Jacobian of the uncoupled 2T2R parallel manipulator is a 4×4 diagonal matrix. Therefore, there exists a one-to-one correspondence between the input velocity space of the actuated joints and the output velocity space of the moving platform. Moreover, both the control design and the path planning of these proposed manipulators are very simple.

A New Approach for Singularity Analysis and Closeness Measurement to Singularities of Parallel Manipulators

2012 ◽  
Vol 4 (4) ◽  
Author(s):  
Xin-Jun Liu ◽  
Chao Wu ◽  
Jinsong Wang
Keyword(s):  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Singularity Analysis ◽  
Challenging Problem ◽  
Performance Indices ◽  
New Approach ◽  
Singular Configurations ◽  
Different Types ◽  
Force Transmissibility ◽  
Singular Configuration

Singularity analysis is one of the most important issues in the field of parallel manipulators. An approach for singularity analysis should be able to not only identify all possible singularities but also explain their physical meanings. Since a parallel manipulator is always out of control at a singularity and its neighborhood, it should work far from singular configurations. However, how to measure the closeness between a pose and a singular configuration is still a challenging problem. This paper presents a new approach for singularity analysis of parallel manipulators by taking into account motion/force transmissibility. Several performance indices are introduced to measure the closeness to singularities. By using these indices, a uniform “metric” can be found to represent the closeness to singularities for different types of nonredundant parallel manipulators.

A new approach to determine the maximal singularity-free zone of 3-RPR planar parallel manipulator

Robotica ◽  
2011 ◽  
Vol 30 (6) ◽  
pp. 1005-1012 ◽  
Author(s):  
G. Abbasnejad ◽  
H. M. Daniali ◽  
S. M. Kazemi
Keyword(s):  
Parallel Manipulator ◽  
Orientation Angle ◽  
Parallel Manipulators ◽  
Swarm Optimization ◽  
New Approach ◽  
Free Zone ◽  
Reference Orientation ◽  
Planar Parallel Manipulator ◽  
Different Types ◽  
Moving Platform

SUMMARYThis paper presents a new algorithm to find the singularity-free cylindrical workspace of parallel manipulators. Because of the limited workspace of parallel manipulators cluttered with different types of singularities, a simple and robust technique to determine continuous singularity-free zones in the workspace of parallel manipulators is required. Here, the largest singularity-free cylinder within the workspace for any prescribed orientation ranging around a reference orientation angle of moving platform is determined. To this end, Particle Swarm Optimization is utilized to find the closest point on the singularity surface to the axis of the cylinder. By implementing the algorithm on 3-RPR planar parallel manipulator, the results show that this algorithm improves the efficiency and leads to significantly larger singularity-free workspace than those reported earlier.

A general dynamic model for a large-scale 2-DOF planar parallel manipulator

Robotica ◽  
1999 ◽  
Vol 17 (6) ◽  
pp. 675-683 ◽  
Author(s):  
Khaled R. Atia ◽  
M.P. Cartmell
Keyword(s):  
Dynamic Model ◽  
Parallel Manipulator ◽  
Large Scale ◽  
Parallel Manipulators ◽  
New Approach ◽  
Planar Parallel Manipulator ◽  
Two Degree Of Freedom ◽  
Planar Parallel Manipulators ◽  
Number Of Cells ◽  
General Dynamic

In this work a new concept of designing two degree of freedom (2-DOF) planar parallel manipulators (PPMs) is presented. With this design the manipulator's workspace can be increased by increasing the number of cells in the manipulator. A general dynamic model is formulated for the manipulator with any number of cells. The model is adapted for SCARA and ADEPT configurations, and a new approach for balancing these type of manipulators is proposed.

A three translational DoFs parallel cube-manipulator

Robotica ◽  
2003 ◽  
Vol 21 (6) ◽  
pp. 645-653 ◽  
Author(s):  
Xin-Jun Liu ◽  
Jay il Jeong ◽  
Jongwon Kim
Keyword(s):  
Coordinate System ◽  
Degrees Of Freedom ◽  
Parallel Manipulators ◽  
Forward Kinematics ◽  
Cartesian Coordinate System ◽  
Micro Motion ◽  
Moving Platform ◽  
Delta Robot ◽  
Cartesian Coordinate

This paper concerns the presentation and analysis of a type of three translational degrees of freedom (DoFs) parallel cube-manipulator. The parallel manipulators are the topology architectures of the DELTA robot and Tsai's manipulator, respectively, which have three translational DoFs. In the design, the three actuators are arranged according to the Cartesian coordinate system, which means that the actuating directions are normal to each other, and the joints connecting to the moving platform are located on three sides of a cube, for such reason we call this type of manipulator the parallel cube-manipulator. The kinematics problems, singularity, workspace, compliance characteristic of the manipulator are investigated in the paper. The analysis results show that the manipulators have the advantages of no singularities in the workspace, relatively more simple forward kinematics, and existence of a compliance center. The parallel cube-manipulator can be applied to the fields of micro-motion manipulators, remote center compliance (RCC) devices, assembly, and so on.

scholarly journals LiDAR-Based Glass Detection for Improved Occupancy Grid Mapping

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2263
Author(s):  
Haileleol Tibebu ◽  
Jamie Roche ◽  
Varuna De Silva ◽  
Ahmet Kondoz
Keyword(s):  
Laser Scanner ◽  
Point Clouds ◽  
Light Detection And Ranging ◽  
Test Results ◽  
New Approach ◽  
Occupancy Grid ◽  
Laser Scanners ◽  
Novel Method ◽  
Occupancy Grid Mapping ◽  
Cartesian Coordinate

Creating an accurate awareness of the environment using laser scanners is a major challenge in robotics and auto industries. LiDAR (light detection and ranging) is a powerful laser scanner that provides a detailed map of the environment. However, efficient and accurate mapping of the environment is yet to be obtained, as most modern environments contain glass, which is invisible to LiDAR. In this paper, a method to effectively detect and localise glass using LiDAR sensors is proposed. This new approach is based on the variation of range measurements between neighbouring point clouds, using a two-step filter. The first filter examines the change in the standard deviation of neighbouring clouds. The second filter uses a change in distance and intensity between neighbouring pules to refine the results from the first filter and estimate the glass profile width before updating the cartesian coordinate and range measurement by the instrument. Test results demonstrate the detection and localisation of glass and the elimination of errors caused by glass in occupancy grid maps. This novel method detects frameless glass from a long range and does not depend on intensity peak with an accuracy of 96.2%.

On the Flexural-Torsional Behavior of a Straight Elastic Beam Subject to Terminal Moments

1993 ◽  
Vol 60 (2) ◽  
pp. 498-505 ◽  
Author(s):  
Z. Tan ◽  
J. A. Witz
Keyword(s):  
Coordinate System ◽  
Cross Section ◽  
Equilibrium Equation ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Elastic Beam ◽  
Cartesian Coordinate System ◽  
Kinematic Constraints ◽  
Torsional Behavior ◽  
Cartesian Coordinate

This paper discusses the large-displacement flexural-torsional behavior of a straight elastic beam with uniform circular cross-section subject to arbitrary terminal bending and twisting moments. The beam is assumed to be free from any kinematic constraints at both ends. The equilibrium equation is solved analytically with the full expression for curvature to obtain the deformed configuration in a three-dimensional Cartesian coordinate system. The results show the influence of the terminal moments on the beam’s deflected configuration.

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