Dynamic Modelling of an Elephant Trunk Like Flexible Bionic Manipulator

Abstract In this paper, an attempt is made to model and study the planar and spatial dynamics of flexible elephant trunk-like manipulator by using multi-body dynamics software MSC-ADAMS. The flexible manipulator is modelled for bending with variable curvature. The entire manipulator length is divided into two sub-sections with associated lumped mass, damping and stiffness for the dynamic analysis. In this model, each section has three pressure actuated bellow tubes, which are modelled as simple spring-damper with the net mass distributed at the ends. Besides, a torsional spring-damper system is also incorporated in each section model to resist the bending about the transverse axes when the pressures in the bellow tubes are unequal. The manipulator is so designed that due to different actuation forces (corresponding to different bellows), the resultant action is finally a bending moment at the tip of each section. The effect of the gravitational force is also included. The change in behaviour of the end-effector position and orientation with respect to time is studied along with the elongation of bellow tubes. The nature of the velocity profile of the end-effector is also determined to study the behaviour of the manipulator.

Download Full-text

Dynamic modelling of planar flexible manipulators: Computational and algorithmic efficiency

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406971521700 ◽

1997 ◽

Vol 211 (2) ◽

pp. 119-133 ◽

Cited By ~ 3

Author(s):

Y-J Shyu ◽

K F Gill

Keyword(s):

Linear Equations ◽

Dynamic Modelling ◽

Approximate Solutions ◽

Experimental Information ◽

Open Loop ◽

Flexible Manipulator ◽

Time Step ◽

End Effector ◽

And Control ◽

Non Linear Equations

Traditionally, many robot arms are very rigid in construction; this was believed to be necessary for accurate placement and repeatability but led to higher material costs and increased energy consumption. Higher operational speeds and the use of lightweight materials cause elastic deformations to occur during the operation of the manipulator. These deformations degrade the path-tracking performance of the end-effector. The dynamic behaviour of a flexible manipulator is described mathematically by non-linear equations which are difficult to solve analytically. Unfortunately, there is currently no experimental information available with which to compare this design of flexible structure. For design and control purposes, it is suggested in this paper that it is more appropriate to employ approximate solutions with the emphasis on the development of a fast computational algorithm. An analytical study was undertaken to investigate the relevant uncertainties that are either inappropriately described or unavailable in the literature. The purpose of the paper is essentially to include the initial deflections in the simulation, to select the size of the time step, to select the models for emulating the end-effector, payload and joint actuator and, finally, to suppress the uncontrollable off-plane vibrations when encountered. When this knowledge has been obtained, the design and development of the simulation process can begin. In order to demonstrate the practicability of the open-loop simulation proposed and test the software, two representative models were investigated.

Download Full-text

Simulation of Accessory Drive Belt Concerning to Slippage and Transversal Vibration

ASME 2006 Internal Combustion Engine Division Spring Technical Conference (ICES2006) ◽

10.1115/ices2006-1340 ◽

2006 ◽

Author(s):

Hiroshi Takagishi ◽

Hiroshi Yoneguchi ◽

Daichi Sakamoto ◽

Atsushi Nagakubo

Keyword(s):

Simulation Method ◽

Dynamics Simulation ◽

Design Stage ◽

Friction Contact ◽

Transversal Vibration ◽

Body Dynamics ◽

The Coefficient Of Friction ◽

Drive Belt ◽

Section Model ◽

Multi Body

A simulation method was proposed to predict the slippage and transversal vibration of the accessory drive belt. To reproduce these phenomena, the accessory drive belt was represented by a section-by-section model in which the belt was replaced by a finite number of masses and springs using multi-body dynamics simulation. In this model, the belt was able to vibrate in both the direction of advance and the direction perpendicular to it, and a friction contact element was defined between the pulley and the belt. The coefficient of friction was made variable with respect to the slippage speed to enable stick and slippage to be predicted. This method allows for accurate simulation of the amount of belt slippage and the amplitude of transversal vibration, thus enabling the optimum belt layout to be determined at the design stage.

Download Full-text

Dynamic Analysis and Control of Industrial Robotic Manipulators

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.883.30 ◽

2018 ◽

Vol 883 ◽

pp. 30-36 ◽

Cited By ~ 1

Author(s):

Yunn Lin Hwang ◽

Jung Kuang Cheng ◽

Van Thuan Truong

Keyword(s):

Control System ◽

Robotic Manipulators ◽

Euler Method ◽

End Effector ◽

Feed Forward Control ◽

Efficient Simulation ◽

Body Dynamics ◽

Multi Body ◽

And Control ◽

Manipulator Robot

Robot simulation has developed quickly in recent decades. Along with the development of computer science, a lot of simulation soft-wares have been created to perform many purposes such as studying kinematic, dynamic, and off-line program to avoid obstacle on manipulator robots. The main objective of this study is therefore to analyze kinematic, dynamic characteristics of an R-R robotic manipulator in order to control this robot. Newton-Euler method was used to calculate the torque acting on each joint of the robot. Then, a numerical model of the robot was established by a multi-body dynamics software to compare with the results obtained by Newton-Euler theory. After that, a feed-forward control system was created by RecurDyn/CoLink to control the end-effector of the robot following a desired trajectory. The results showed that this research can be used for efficient simulation of structural kinematics, dynamics as well as control of the real manipulator robot with the robot structure in a virtual environment.

Download Full-text

Simulation analysis of helicopter blade properties based on multi-body dynamics

Advanced Control, Automation and Robotics ◽

10.2495/acar140611 ◽

2015 ◽

Author(s):

J.L. He ◽

Y. Tan ◽

Y.R. Ma ◽

L. Xu ◽

T. Wang

Keyword(s):

Simulation Analysis ◽

Helicopter Blade ◽

Body Dynamics ◽

Multi Body

Download Full-text

Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics

Biology Letters ◽

10.1098/rsbl.2012.0056 ◽

2012 ◽

Vol 8 (4) ◽

pp. 660-664 ◽

Cited By ~ 54

Author(s):

K. T. Bates ◽

P. L. Falkingham

Keyword(s):

Body Size ◽

Feeding Behaviour ◽

Ontogenetic Change ◽

Positive Allometry ◽

Musculoskeletal Models ◽

Terrestrial Animal ◽

Body Dynamics ◽

Mode Of Life ◽

Scaling Analyses ◽

Multi Body

Bite mechanics and feeding behaviour in Tyrannosaurus rex are controversial. Some contend that a modest bite mechanically limited T. rex to scavenging, while others argue that high bite forces facilitated a predatory mode of life. We use dynamic musculoskeletal models to simulate maximal biting in T. rex . Models predict that adult T. rex generated sustained bite forces of 35 000–57 000 N at a single posterior tooth, by far the highest bite forces estimated for any terrestrial animal. Scaling analyses suggest that adult T. rex had a strong bite for its body size, and that bite performance increased allometrically during ontogeny. Positive allometry in bite performance during growth may have facilitated an ontogenetic change in feeding behaviour in T. rex , associated with an expansion of prey range in adults to include the largest contemporaneous animals.

Download Full-text

Sir Robert Stawell Ball and methodologies of modern screw theory

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406021524828 ◽

2002 ◽

Vol 216 (1) ◽

pp. 1-11 ◽

Cited By ~ 9

Author(s):

H Lipkin ◽

J Duffy

Keyword(s):

Computational Geometry ◽

Rigid Body ◽

Lie Algebra ◽

Screw Theory ◽

Mechanical Design ◽

Ball Screw ◽

Dual Numbers ◽

Body Dynamics ◽

Rigid Body Mechanics ◽

Multi Body

The theory of screws was largely developed by Sir Robert Stawell Ball over 100 years ago to investigate general problems in rigid body mechanics. Nowadays, screw theory is applied in many different but related forms including dual numbers, Plilcker coordinates and Lie algebra. An overview of these methodologies is presented along with a perspective on Ball. Screw theory has re-emerged after a hiatus to become an important tool in robot mechanics, mechanical design, computational geometry and multi-body dynamics.

Download Full-text