scholarly journals Dynamic modelling and force analysis of a knuckle boom crane using screw theory

2019 ◽  
Vol 133 ◽  
pp. 179-194 ◽  
Author(s):  
Andrej Cibicik ◽  
Olav Egeland
Keyword(s):  
Screw Theory ◽  
Dynamic Modelling ◽  
Force Analysis ◽  
Boom Crane

Repelling-Screw Based Force Analysis of Origami Mechanisms

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Chen Qiu ◽  
Ketao Zhang ◽  
Jian S. Dai
Keyword(s):  
Parallel Mechanism ◽  
Screw Theory ◽  
Reaction Force ◽  
Theoretical Background ◽  
Force Analysis ◽  
Modeling Approach ◽  
Reaction Forces ◽  
Redundantly Actuated

This paper provides an approach to model the reaction force of origami mechanisms when they are deformed. In this approach, an origami structure is taken as an equivalent redundantly actuated mechanism, making it possible to apply the forward-force analysis to calculating the reaction force of the origami structure. Theoretical background is provided in the framework of screw theory, where the repelling screw is introduced to integrate the resistive torques of folded creases into the reaction-force of the whole origami mechanism. Two representative origami structures are then selected to implement the developed modeling approach, as the widely used waterbomb base and the waterbomb-based integrated parallel mechanism. With the proposed kinematic equivalent, their reaction forces are obtained and validated, presenting a ground for force analysis of origami-inspired mechanisms.

Analysis on the Instantaneous Stiffness of the 3-RPS Parallel Machine

2009 ◽  
Vol 407-408 ◽  
pp. 63-67 ◽  
Author(s):  
Xian Guo Han ◽  
Xue Liang Cui ◽  
Wu Yi Chen
Keyword(s):  
Jacobian Matrix ◽  
Screw Theory ◽  
Parallel Machine ◽  
Force Analysis ◽  
Stiffness Model ◽  
Generalized Force ◽  
Moving Platform ◽  
Position And Orientation

Based on the screw theory, the force analysis of the 3-RPS parallel machine is illuminated. Been equivalent to a 6-chain parallel machine, the deformation harmony equation of the parallel machine under the outside generalized force is interpreted. The instantaneous stiffness model of the parallel machine, which includes the change of the force Jacobian matrix, is established. Considering the deviation of the position and orientation of the moving platform, which is resulted from the distortion of the PRS chains of the parallel machine, the influence of the change of the Jacobian matrix to the instantaneous stiffness model of the 3-RPS parallel machine is analyzed, and furthermore, it is verified with an instance.

Kinematic and Force Analysis of Articulated Mechanical Hands

1983 ◽  
Vol 105 (1) ◽  
pp. 35-41 ◽  
Author(s):  
J. K. Salisbury ◽  
B. Roth
Keyword(s):  
Screw Theory ◽  
Force Analysis ◽  
Different Types ◽  
Basic Concepts ◽  
Number Synthesis ◽  
Object Relative ◽  
Mechanical Hands

This paper deals with several of the basic concepts in the kinematics of mechanical hands. Several different types of finger contacts are modeled and used in a number synthesis of three-fingered hands. Screw theory is used to show which finger configurations allow complete immobilization of the gripped object relative to the fingers, and also allow for the manipulation of the object by the fingers while maintaining the grasp. Shown in this paper is how to determine the forces applied by the fingers on the object, and also how to compute the velocities of the fingers and the object. The analysis developed in this paper is shown to lead to a hand with three fingers, each with three turning joints, and having friction contacts with an object at three separate points.

Force Analysis of Spatial Single Closed-Loop Overconstrained Mechanisms

2016 ◽  
Author(s):  
Wenlan Liu ◽  
Yundou Xu ◽  
Jiantao Yao ◽  
Yongsheng Zhao
Keyword(s):  
Closed Loop ◽  
Screw Theory ◽  
Driving Forces ◽  
Parallel Mechanisms ◽  
Force Analysis ◽  
Moving Platform ◽  
Compliance Matrices ◽  
Overconstrained Mechanisms ◽  
Force Problem ◽  
Deformation Compatibility

Taking the Bennett and Schatz mechanisms as examples, force analyses of spatial single closed-loop (SSCL) overconstrained mechanisms are demonstrated aiming to obtain the driving forces/torques and joint reactions of this kind of mechanisms. Firstly, regarding the SSCL overconstrained mechanisms as parallel mechanisms with two supporting limbs, the constraint wrenches and actuation wrenches imposed on the moving platform by the two limbs are discussed, and the mobility of each mechanism is analyzed based on the screw theory. Then, the compliance matrices of the limbs’ constraint wrenches are derived, which contribute to solve the statically indeterminate force problem of the mechanisms. Next, by combining the force and moment equilibrium equation of the moving platform with the deformation compatibility equation of the corresponding mechanism, the magnitudes of all constraint wrenches and actuation wrenches are solved. Furthermore, the driving forces/torques and joint reactions are derived. Finally, the numerical and simulation results of the two mechanisms are presented.

scholarly journals Dynamic modelling of a 3-CPU parallel robot via screw theory

2013 ◽  
Vol 4 (1) ◽  
pp. 185-197 ◽  
Author(s):  
L. Carbonari ◽  
M. Battistelli ◽  
M. Callegari ◽  
M.-C. Palpacelli
Keyword(s):  
Dynamic Analysis ◽  
Research Group ◽  
Screw Theory ◽  
Virtual Work ◽  
Dynamic Modelling ◽  
Parallel Robot ◽  
Computationally Efficient ◽  
Virtual Work Principle ◽  
Model Based ◽  
Advanced Model

Abstract. The article describes the dynamic modelling of I.Ca.Ro., a novel Cartesian parallel robot recently designed and prototyped by the robotics research group of the Polytechnic University of Marche. By means of screw theory and virtual work principle, a computationally efficient model has been built, with the final aim of realising advanced model based controllers. Then a dynamic analysis has been performed in order to point out possible model simplifications that could lead to a more efficient run time implementation.

Stiffness Design, Analysis and Validation of a Parallel-Mechanism Equivalent Suspension System

2015 ◽  
Author(s):  
Chen Qiu ◽  
Ketao Zhang ◽  
Jing Shan Zhao ◽  
Jian S. Dai
Keyword(s):  
Parallel Mechanism ◽  
Optimization Design ◽  
Screw Theory ◽  
Suspension System ◽  
Force Analysis ◽  
Design Constraint ◽  
Kinematic Design ◽  
Simulation Validation ◽  
Element Simulation ◽  
Stiffness Design

This paper provides a systematic approach to design a vehicle’s independent suspension system. In this approach, multi-link type suspension is selected. By treating it as a parallel mechanism, both the kinematic design and force analysis are conducted in the same framework of screw theory. Regarding the kinematic design, constraint-based approach is used to find suitable layouts of constraint limbs in accordance with desired degree of freedom. In the force analysis, stiffness matrix of the suspension mechanism is developed, leading to the deformation and stress analysis under various critical loads. The developed formulae are further utilized to design suitable suspension mechanism, followed by finite-element-simulation validation as well as optimization design to reduce the resulted maximum stresses.

A force analysis of a 3-RPS parallel mechanism by using screw theory

Robotica ◽  
2011 ◽  
Vol 29 (7) ◽  
pp. 959-965 ◽  
Author(s):  
Y. Zhao ◽  
J. F. Liu ◽  
Z. Huang
Keyword(s):  
Parallel Mechanism ◽  
Screw Theory ◽  
Mechanical Design ◽  
Parallel Manipulators ◽  
Simultaneous Equations ◽  
Force Analysis ◽  
New Approach ◽  
Numerical Example ◽  
And Control

SUMMARYThe force analysis of parallel manipulators is one of the important issues for mechanical design and control, but it is quite difficult often because of the excessive unknowns. A new approach using screw theory for a 3-RPS parallel mechanism is proposed in this paper. It is able to markedly reduce the number of unknowns and even make the number of simultaneous equations to solve not more than six each time, which may be called force decoupling. With this method, first the main-pair reactions need to be solved for, and then, the active forces and constraint reactions of all other kinematic pairs can be simultaneously obtained by analyzing the equilibrium of each body one by one. Finally, a numerical example and a discussion are given.

scholarly journals Static Force Analysis of a 3-DOF Robot for Spinal Vertebral Lamina Milling

Machines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 29
Author(s):  
Shaodong Li ◽  
Peiyuan Gao ◽  
Hongjian Yu ◽  
Mingqi Chen
Keyword(s):  
Screw Theory ◽  
Kinematic Model ◽  
Force Model ◽  
Static Force ◽  
Force Analysis ◽  
Joint Force ◽  
Simulation Results ◽  
The Mathematical Model ◽  
Human Robot Collaboration

In order to realize robot-assisted spinal laminectomy surgery and meet the clinical needs of the robot workspace, including accuracy in human–robot collaboration, an asymmetrical 3-DOF spatial translational robot is proposed, which can realize spinal laminectomy in a fixed posture. First, based on the screw theory, the constraint screw system of the robot was established, and the degree of freedom was derived to verify the spatial translational ability of the robot. Then, a kinematic model of the robot was established, and a static force model of the robot was derived based on the kinematic model. The mathematical relationship between the external force and the joint force/torque was obtained, with the quality of all links considered in the model. Finally, we modeled the robot and imported it into ADAMS to obtain the static force simulation results of the 3D model. The force error was approximately 0.001 N and the torque error was approximately 0.0001 N∙m compared with the simulation results of the mathematical model, accounting for 1% of the joint force/torque, which is acceptable. The result also showed the correctness of the mathematical models, and provides a theoretical basis for motion control and human–robot collaboration.

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