Model Validation of an Octopus Inspired Continuum Robotic Arm for Use in Underwater Environments

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Tianjiang Zheng ◽  
David T. Branson ◽  
Emanuele Guglielmino ◽  
Rongjie Kang ◽  
Gustavo A. Medrano Cerda ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Model Validation ◽  
Degrees Of Freedom ◽  
Robotic Arm ◽  
Octopus Vulgaris ◽  
Light Weight ◽  
Continuum Robots ◽  
Continuum Structure ◽  
External Forces ◽  
Good Agreement

Octopuses are an example of dexterous animals found in nature. Their arms are flexible, can vary in stiffness, grasp objects, apply high forces with respect to their relatively light weight, and bend in all directions. Robotic structures inspired by octopus arms have to undertake the challenges of a high number of degrees of freedom (DOF), coupled with highly flexible continuum structure. This paper presents a kinematic and dynamic model for underwater continuum robots inspired by Octopus vulgaris. Mass, damping, stiffness, and external forces such as gravity, buoyancy, and hydrodynamic forces are considered in the dynamic model. A continuum arm prototype was built utilizing longitudinal and radial actuators, and comparisons between the simulated and experimental results show good agreement.

scholarly journals Functional Evaluation of Asibot: A New Approach on Portable Robotic System for Disabled People

2012 ◽  
Vol 9 (1) ◽  
pp. 85-97 ◽  
Author(s):  
Alberto Jardón ◽  
Concepción A. Monje ◽  
Carlos Balaguer
Keyword(s):  
Control System ◽  
Degrees Of Freedom ◽  
The Elderly ◽  
Robotic Arm ◽  
Functional Evaluation ◽  
Light Weight ◽  
Disabled People ◽  
New Approach ◽  
Human Care ◽  
Different Levels

In this work, an innovative robotic solution for human care and assistance is presented. Our main objective is to develop a new concept of portable robot able to support the elderly and those people with different levels of disability during the execution of daily tasks, such as washing their face or hands, brushing their teeth, combing their hair, eating, drinking, and bringing objects closer, among others. Our prototype, ASIBOT, is a five degrees of freedom (DOF) self-contained manipulator that includes the control system and electronic equipment on board. The main advantages of the robot are its light weight, about 11 kg for a 1.3 m reach, its autonomy, and its ability to move between different points (docking stations) of the room or from the environment to a wheelchair and vice versa, which facilitates its supportive functions. The functional evaluation of ASIBOT is addressed in this paper. For this purpose the robotic arm is tested in different experiments with disabled people, gathering and discussing the results according to a methodology that allows us to assess users' satisfaction.

Design of a master device for controlling multi-moduled continuum robots

2015 ◽  
Vol 231 (10) ◽  
pp. 1921-1931 ◽  
Author(s):  
Hyun-Soo Yoon ◽  
Byung-Ju Yi
Keyword(s):  
Degrees Of Freedom ◽  
Control Experiment ◽  
Light Weight ◽  
Kinematic Structure ◽  
Continuum Robots ◽  
Two Degrees Of Freedom ◽  
Forward Kinematic ◽  
Master Device ◽  
Kinematic Solution

Few interface systems designed to control continuum robots have been developed. This work presents a master device for multi-unit continuum robots. The master mechanism has the same kinematic structure as the slave device. The kinematic structure, which uses a spring as a backbone, allows for a unique forward kinematic solution. This design is slim-sized, light-weight, and easy to implement. As an example mechanism, a continuum unit with two degrees of freedom was developed. Two-unit modules were assembled to generate four degrees of freedom. The performance of the master device is verified through a master-slave control experiment.

A dispersion based model for anaerobic digestion of solid cattle wastes in a stratified thermophilic accumulation system

2005 ◽  
Vol 52 (1-2) ◽  
pp. 195-202 ◽  
Author(s):  
H.M. El-Mashad ◽  
W.K.P. van Loon ◽  
G. Zeeman ◽  
G.P.A. Bot ◽  
G. Lettinga
Keyword(s):  
Experimental Data ◽  
Anaerobic Digestion ◽  
Aspect Ratio ◽  
Dynamic Model ◽  
Model Validation ◽  
Methane Production ◽  
System Performance ◽  
Aspect Ratios ◽  
Accumulation System ◽  
Good Agreement

A dynamic model has been developed to describe the anaerobic digestion of solid cattle waste in an accumulation system (AC). To calibrate the model an experiment was carried out at a lab-scale AC at 50 °C. The predicted methane production shows a very good agreement (i.e. R2=0.998) with the experimental data. However less agreement is evident for the intermediates. After model validation the model was applied to study the effect of different aspect ratios on the system performance. An optimum aspect ratio of 2–3 could be determined.

scholarly journals Variable Curvature Modelling Method of Continuum Robots with Contraints

2021 ◽  
Author(s):  
Peng Chen ◽  
Yi Yu ◽  
Yuwang Liu
Keyword(s):  
Degrees Of Freedom ◽  
Human Robot Interaction ◽  
Great Promise ◽  
Complex Deformation ◽  
Continuum Robots ◽  
Mechanics Model ◽  
Variable Curvature ◽  
Main Challenge ◽  
High Flexibility ◽  
External Forces

Abstract The inherent compliance of continuum robots holds great promise in the fields of soft manipulation and safe human-robot interaction. This compliance reduces the risk of damage to the manipulated object and the surroundings. However, continuum robots have theoretically infinite degrees of freedom, and this high flexibility usually leads to complex deformations with external forces and positional constraints. How to describe this complex deformation is the main challenge for modelling continuum robots. In this study, we investigated a novel variable curvature modeling method for continuum robots, considering external forces and positional constraints. The robot configuration curve is described by the developed mechanics model, and then the robot is fitted to the curve. To validate the model, a 10-section continuum robot prototype with a length of 1 m was developed. The ability of the robot to reach the target points and track complex trajectories with load verified the feasibility and accuracy of the model. The ratio of the average position error of the robot endpoint to the robot length was less than 2.38%. This work may serve a new perspective for design analysis and motion control of continuum robots.

Dynamic Modeling of the Cable-Driven Continuum Robots in Hybrid Position-Force Actuation Mode

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Abbas Ehsani-Seresht ◽  
Shahin Hashemi-Pour Moosavi
Keyword(s):  
Dynamic Model ◽  
Dynamic Models ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Computational Effort ◽  
Continuum Robots ◽  
Friction Forces ◽  
Lagrange Formulation ◽  
Statics And Dynamics ◽  
External Forces

Abstract Dynamic models of the cable-driven continuum robots are commonly employed for those robots that are actuated by the cables’ forces. In this paper, a dynamic model is proposed for the cable-driven continuum robots actuated by position and/or force actuated cables, which is appropriate for any desired number of actuation cables and their routing. The robot is supposed to have an extensible backbone with the capability of bending and torsion in three-dimensional spaces. The proposed dynamic model is developed based on the Euler–Lagrange formulation of equations of motion taking into account all the effective forces including gravity force, cable actuation forces, external forces, and cable-disk friction forces. Furthermore, an iterative numerical solution method is presented for the dynamic model which requires much less memory and computational effort in comparison with the closed-form methods. The static model of the robots is also developed based on the dynamic model and the results obtained from the simulations and experiments are used for the validation of the static and dynamic models. The final results indicate the accuracy of the proposed models for estimating the kinematics, statics, and dynamics of the cable-driven continuum robots.

Dynamic Modeling for a Continuum Robot With Compliant Structure

2015 ◽  
Author(s):  
Yong Guo ◽  
Rongjie Kang ◽  
Lisha Chen ◽  
Jian Dai
Keyword(s):  
Continuum Robots ◽  
Modeling And Control ◽  
3 Dimensional ◽  
Compliant Structure ◽  
Continuum Robot ◽  
Mass Damper ◽  
Spring System ◽  
External Forces ◽  
And Control ◽  
Good Agreement

Continuum robots have attracted increasing focus in recent years due to their intrinsic compliance and safety. However, the modeling and control of such robots are complex in comparison with conventional rigid ones. This paper presents the design of a pneumatically actuated continuum robot. A 3-dimensional dynamic model is then developed by using the mass-damper-spring system based networks, in which elastic deformation, actuating forces and external forces are taken into account. The model is validated by experiments and shows good agreement with the robotic prototype.

The Development of a Myoelectric Training Tool for Above-Elbow Amputees

2012 ◽  
Vol 6 (1) ◽  
pp. 5-15 ◽  
Author(s):  
Michael R Dawson ◽  
Farbod Fahimi ◽  
Jason P Carey
Keyword(s):  
Degrees Of Freedom ◽  
Learning Task ◽  
Robotic Arm ◽  
Signal Acquisition ◽  
Myoelectric Prosthesis ◽  
Training Tool ◽  
Myoelectric Prostheses ◽  
Training Systems ◽  
Targeted Muscle Reinnervation

The objective of above-elbow myoelectric prostheses is to reestablish the functionality of missing limbs and increase the quality of life of amputees. By using electromyography (EMG) electrodes attached to the surface of the skin, amputees are able to control motors in myoelectric prostheses by voluntarily contracting the muscles of their residual limb. This work describes the development of an inexpensive myoelectric training tool (MTT) designed to help upper limb amputees learn how to use myoelectric technology in advance of receiving their actual myoelectric prosthesis. The training tool consists of a physical and simulated robotic arm, signal acquisition hardware, controller software, and a graphical user interface. The MTT improves over earlier training systems by allowing a targeted muscle reinnervation (TMR) patient to control up to two degrees of freedom simultaneously. The training tool has also been designed to function as a research prototype for novel myoelectric controllers. A preliminary experiment was performed in order to evaluate the effectiveness of the MTT as a learning tool and to identify any issues with the system. Five able-bodied participants performed a motor-learning task using the EMG controlled robotic arm with the goal of moving five balls from one box to another as quickly as possible. The results indicate that the subjects improved their skill in myoelectric control over the course of the trials. A usability survey was administered to the subjects after their trials. Results from the survey showed that the shoulder degree of freedom was the most difficult to control.

Dynamic model for high-speed rotors based on their experimental characterization

2017 ◽  
Vol 2 (4) ◽  
pp. 25
Author(s):  
L. A. Montoya ◽  
E. E. Rodríguez ◽  
H. J. Zúñiga ◽  
I. Mejía
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Experimental Characterization ◽  
Rotating Systems ◽  
Computing Performance ◽  
The Impact ◽  
Stiffness Distribution ◽  
Good Agreement

Rotating systems components such as rotors, have dynamic characteristics that are of great importance to understand because they may cause failure of turbomachinery. Therefore, it is required to study a dynamic model to predict some vibration characteristics, in this case, the natural frequencies and mode shapes (both of free vibration) of a centrifugal compressor shaft. The peculiarity of the dynamic model proposed is that using frequency and displacements values obtained experimentally, it is possible to calculate the mass and stiffness distribution of the shaft, and then use these values to estimate the theoretical modal parameters. The natural frequencies and mode shapes of the shaft were obtained with experimental modal analysis by using the impact test. The results predicted by the model are in good agreement with the experimental test. The model is also flexible with other geometries and has a great time and computing performance, which can be evaluated with respect to other commercial software in the future.

Estimation of the Thermodynamic Properties of Branched Hydrocarbons

2000 ◽  
Vol 122 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Hui He ◽  
Mohamad Metghalchi ◽  
James C. Keck
Keyword(s):  
Thermodynamic Properties ◽  
Degrees Of Freedom ◽  
Statistical Thermodynamic ◽  
Motion Modes ◽  
Branched Alkanes ◽  
Branched Hydrocarbons ◽  
Wide Range ◽  
On Line ◽  
Kinetic Calculations ◽  
Good Agreement

A simple model has been developed to estimate the sensible thermodynamic properties such as Gibbs free energy, enthalpy, heat capacity, and entropy of hydrocarbons over a wide range of temperatures with special attention to the branched molecules. The model is based on statistical thermodynamic expressions incorporating translational, rotational and vibrational motions of the atoms. A method to determine the number of degrees of freedom for different motion modes (bending and torsion) has been established. Branched rotational groups, such as CH3 and OH, have been considered. A modification of the characteristic temperatures for different motion mode has been made which improves the agreement with the exact values for simple cases. The properties of branched alkanes up to 2,3,4,-trimthylpentane have been calculated and the results are in good agreement with the experimental data. A relatively small number of parameters are needed in this model to estimate the sensible thermodynamic properties of a wide range of species. The model may also be used to estimate the properties of molecules and their isomers, which have not been measured, and is simple enough to be easily programmed as a subroutine for on-line kinetic calculations. [S0195-0738(00)00902-X]

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