A Rolling 8-Bar Linkage Mechanism

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Yaobin Tian ◽  
Yan-An Yao ◽  
Jieyu Wang
Keyword(s):  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Rolling Direction ◽  
Linkage Mechanism ◽  
Zero Moment Point ◽  
Revolute Joints ◽  
Straight Line ◽  
Polygonal Region ◽  
Zero Moment

In this paper, a rolling mechanism constructed by a spatial 8-bar linkage is proposed. The eight links are connected with eight revolute joints, forming a single closed-loop with two degrees of freedom (DOF). By kinematic analysis, the mechanism can be deformed into planar parallelogram or spherical 4-bar mechanism (SFM) configuration. Furthermore, this mechanism can be folded onto a plane at its singularity positions. The rolling capability is analyzed based on the zero-moment-point (ZMP) theory. In the first configuration, the mechanism can roll along a straight line. In the second configuration, it can roll along a polygonal region and change its rolling direction. By alternatively choosing one of the two configurations, the mechanism has the capability to roll along any direction on the ground. Finally, a prototype was manufactured and some experiments were carried out to verify the functions of the mechanism.

A rolling mechanism with two modes of planar and spherical linkages

2015 ◽  
Vol 230 (12) ◽  
pp. 2110-2123 ◽  
Author(s):  
Jieyu Wang ◽  
Yanan Yao ◽  
Xianwen Kong
Keyword(s):  
Kinematic Analysis ◽  
Control Strategies ◽  
Point Theory ◽  
The Novel ◽  
Standing Posture ◽  
Zero Moment Point ◽  
Rolling Mechanism ◽  
Straight Line ◽  
Zero Moment ◽  
Spherical Linkages

A novel deformable rolling mechanism is proposed in this paper. The mechanism can switch between two modes: a planar linkage mode and a spherical linkage mode. In the planar linkage mode, the mechanism rolls like a planar four-bar mechanism and moves along a straight line. In the spherical linkage mode, the mechanism rolls as a spherical four-bar mechanism and moves along a polygon. A standing posture, which likes an upright pyramid, of the rolling mechanism is also identified. After the description of the novel mechanism, the kinematic analysis of the mechanism is presented, and appropriate control strategies are proposed. Then, the rolling conditions of the mechanism are investigated based on the zero-moment-point theory. Finally, the various modes of the mechanism are verified by both simulations and prototype experiments.

scholarly journals Conceptual Design and Computational Modeling Analysis of a Single-Leg System of a Quadruped Bionic Horse Robot Driven by a Cam-Linkage Mechanism

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Liangwen Wang ◽  
Weiwei Zhang ◽  
Caidong Wang ◽  
Fannian Meng ◽  
Wenliao Du ◽  
...  
Keyword(s):  
Motion Analysis ◽  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Kinematic Modeling ◽  
Linkage Mechanism ◽  
Vector Method ◽  
Pressure Angle ◽  
End Point

In this study, the configuration of a bionic horse robot for equine-assisted therapy is presented. A single-leg system with two degrees of freedom (DOFs) is driven by a cam-linkage mechanism, and it can adjust the span and height of the leg end-point trajectory. After a brief introduction on the quadruped bionic horse robot, the structure and working principle of a single-leg system are discussed in detail. Kinematic analysis of a single-leg system is conducted, and the relationships between the structural parameters and leg trajectory are obtained. On this basis, the pressure angle characteristics of the cam-linkage mechanism are studied, and the leg end-point trajectories of the robot are obtained for several inclination angles controlled by the rotation of the motor for the stride length adjusting. The closed-loop vector method is used for the kinematic analysis, and the motion analysis system is developed in MATLAB software. The motion analysis results are verified by a three-dimensional simulation model developed in Solidworks software. The presented research on the configuration, kinematic modeling, and pressure angle characteristics of the bionic horse robot lays the foundation for subsequent research on the practical application of the proposed bionic horse robot.

scholarly journals Automated Kinematic Analysis of Closed-Loop Planar Link Mechanisms

Machines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 41
Author(s):  
Tatsuya Yamamoto ◽  
Nobuyuki Iwatsuki ◽  
Ikuma Ikeda
Keyword(s):  
Kinematic Analysis ◽  
Closed Loop ◽  
Analysis Procedure ◽  
Linkage Mechanism ◽  
A Algorithm ◽  
Analysis Process ◽  
Type Transformation ◽  
Extraction Algorithm ◽  
Relationship Of ◽  
The Relationship

The systematic kinematic analysis method for planar link mechanisms based on their unique procedures can clearly show the analysis process. The analysis procedure is expressed by a combination of many kinds of conversion functions proposed as the minimum calculation units for analyzing a part of the mechanism. When it is desired to perform this systematic kinematics analysis for a specific linkage mechanism, expert researchers can accomplish the analysis by searching for the procedure by themselves, however, it is difficult for non-expert users to find the procedure. This paper proposes the automatic procedure extraction algorithm for the systematic kinematic analysis of closed-loop planar link mechanisms. By limiting the types of conversion functions to only geometric calculations that are related to the two-link chain, the analysis procedure can be represented by only one type transformation function, and the procedure extraction algorithm can be described as a algorithm searching computable 2-link chain. The configuration of mechanism is described as the “LJ-matrix”, which shows the relationship of connections between links with pairs. The algorithm consists of four sub-processes, namely, “LJ-matrix generator”, “Solver process”, “Add-link process”, and “Over-constraint resolver”. Inputting the sketch of the mechanism into the proposed algorithm, it automatically extracts unique analysis procedure and generate a kinematic analysis program as a MATLAB code based on it. Several mechanisms are analyzed as examples to show the usefulness of the proposed method.

scholarly journals Design and Kinematic Analysis of a Novel 2-DoF Closed-Loop Mechanism for the Actuation of Machining Robots

2021 ◽  
Author(s):  
Angelica Ginnante ◽  
François Leborne ◽  
Stéphane Caro ◽  
Enrico Simetti ◽  
Giuseppe Casalino
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Parallel Mechanisms ◽  
Serial Manipulators ◽  
Hard Materials ◽  
Serial Robots ◽  
Revolute Joints ◽  
Machining Robot ◽  
Kinematic Models ◽  
Kinematic Performance

Abstract The essential characteristics of machining robots are their stiffness and their accuracy. For machining tasks, serial robots have many advantages such as large workspace to footprint ratio, but they often lack the stiffness required for accurately milling hard materials. One way to increase the stiffness of serial manipulators is to make their joints using closed-loop or parallel mechanisms instead of using classical prismatic and revolute joints. This increases the accuracy of a manipulator without reducing its workspace. This paper introduces an innovative two degrees of freedom closed-loop mechanism and shows how it can be used to build serial robots featuring both high stiffness and large workspace. The design of this mechanism is described through its geometric and kinematic models. Then, the kinematic performance of the mechanism is analyzed, and a serial arrangement of several such mechanisms is proposed to obtain a potential design of a machining robot.

Kinematic Analysis of Spatial Mechanisms Via Successive Screw Displacements

1975 ◽  
Vol 97 (2) ◽  
pp. 739-747 ◽  
Author(s):  
Dilip Kohli ◽  
A. H. Soni
Keyword(s):  
Closed Form ◽  
Kinematic Analysis ◽  
Closed Loop ◽  
Displacement Velocity ◽  
Spatial Mechanism ◽  
Spatial Mechanisms ◽  
Straight Line ◽  
Unified Method

A new, unified method is proposed and demonstrated to conduct kinematic analysis of spatial mechanisms involving revolute, cylindrical, prismatic, helical and spherical pairs. The paper derives the equations for the successive screw displacements, and the equations for pair constraints. Using these equations, closed-form relationships for displacement, velocity and acceleration of single or multi-loop spatial mechanisms are obtained by (1) breaking the mechanism at a critical joint (2) unfolding the mechanism along a straight line (3) providing successive screw displacement at each joint and (4) reassembling the mechanism to form a closed loop. The application of this newly developed approach is demonstrated by considering an example of a two-loop spatial mechanism with revolute, cylindrical and spherical pairs.

The QuadroG Robot, a Parallel Robot With a Configurable Platform for Haptic Applications

2015 ◽  
Author(s):  
Salua Hamaza ◽  
Patrice Lambert ◽  
Marco Carricato ◽  
Just Herder
Keyword(s):  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Parallel Robot ◽  
Parallel Robots ◽  
End Effector ◽  
Contact Points ◽  
Loop Chain ◽  
End Effectors ◽  
4 Degrees Of Freedom

This paper explores the fundamentals of parallel robots with configurable platforms (PRCP), as well as the design and the kinematic analysis of those. The concept behind PRCP is that the rigid (non-configurable) end-effector is replaced by a closed-loop chain, the configurable platform. The use of a closed-loop chain allows the robot to interact with the environment from multiple contact points on the platform, which reflects the presence of multiple end-effectors. This results in a robot that successfully combines motion and grasping capabilities into a structure that provides an inherent high stiffness. This paper aims to introduce the QuadroG robot, a 4 degrees of freedom PRCP which finely merges planar motion together with grasping capabilities.

Closed-Loop Tape Springs as Fully Compliant Mechanisms: Preliminary Investigations

2004 ◽  
Author(s):  
Christine Vehar ◽  
Sridhar Kota ◽  
Robert Dennis
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Compliant Mechanisms ◽  
Variable Stiffness ◽  
Small Radius ◽  
Constant Thickness ◽  
Revolute Joints ◽  
Spring Mechanism ◽  
Actuation Scheme ◽  
Straight Segments

The paper introduces tape springs as elements of fully compliant mechanisms. The localized folds of tape springs serve as compact revolute joints, with a very small radius and large range of motion, and the unfolded straight segments serve as links. By exploiting a tape spring’s ability to function as both links and joints, we present a new method of realizing fully compliant mechanisms with further simplification in their construction. Tape springs, typically found in carpenter tape rules, are thin-walled strips having constant thickness, zero longitudinal curvature, and a constant transverse curvature. The paper presents a closed-loop tape spring mechanism. By representing its folds as idealized revolute joints and its variable length links as sliding joints connecting rigid links, we present a modified Gruebler’s equation to determine its kinematic and idle degrees of freedom. To realize practical utility of tape spring mechanisms, we propose a simple actuation scheme incorporating shape memory alloy (SMA) wire actuators and successfully demonstrate its performance with a proof-of-concept prototype. The paper also presents potential applications for actuated tape spring mechanisms including a large displacement translational mechanism, planar positioning mechanisms, bi-stable, multi-stable, and variable stiffness mechanisms.

scholarly journals A Versitile Method to Design a Three Fingered Robotic Arm using Cad and Matlab Technique

2019 ◽  
Vol 8 (4) ◽  
pp. 308-310
Keyword(s):  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Robotic Arm ◽  
Cad Model ◽  
Kinematic Redundancy ◽  
Work Space ◽  
Revolute Joints ◽  
Human Arm

The main objective of the paper is to design a versatile Robotic Arm that has the capability to mimic the motion of a snake such that work space of the robotic arm is maximized. Design is made to achieve maximum mobility of the Robotic Arm such that it can pick up things and placed in very complex scenarios. The design is able to give degrees of freedom to the robot so that it becomes more versatile. It has a kinematic redundancy, like that of a human arm that enables us to place objects in various orientations. This Robotic arm is equipped with a three fingered gripper that provides for efficient grasping. The paper also provides design details of three fingered gripper that is suitable to hold cylindrical objects such as bolts, cable connectors etc. Autodesk Fusion 360 has been used to make cad model of arm and grippers. The 3D arm and gripper are assembled with revolute joints. The robot is tested for its mobility by performing Kinematic Analysis.

scholarly journals CYCLOIDAL GAIT WITH DOUBLE SUPPORT PHASE FOR THE NAO HUMANOID ROBOT

2019 ◽  
Vol 6 ◽  
pp. 83-94
Author(s):  
Jesus E. Fierro P. ◽  
J. Alfonso Pamanes G. ◽  
Victor De-Leon-Gomez
Keyword(s):  
Humanoid Robot ◽  
Experimental Tests ◽  
Zero Moment Point ◽  
Double Support ◽  
Revolute Joints ◽  
Zero Moment ◽  
The Stability ◽  
Reduced Mobility ◽  
Support Phase ◽  
Double Support Phase

The commercial Nao humanoid robot has 11 DOF in legs. Even if these legs include 12 revolute joints, only 11 actuators are employed to control the walking of the robot. Under such conditions, the mobility of the pelvis and that of the oscillating foot are mutually constrained at each step. Besides, the original gait provided by the manufacturer company of the Nao employs only single support phases during the walking. Because of both issues, the reduced mobility in legs and the use of only single support phases, the stability of the walking is affected. To contribute to improving such stability, in this paper an approach is proposed that incorporates a double support phase and a gait based on cycloidal time functions for motions of the pelvis and those of the oscillating foot. To assess the stability of the walking an index is applied, which is based on the notion of zero-moment point (ZMP) of the static foot at each step. Results of experimental tests show that the proposed gait enhances the stability of the robot during the walking.

Sign in / Sign up

Export Citation Format

Share Document