Mechanics Modeling of Multisegment Rod-Driven Continuum Robots

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
William S. Rone ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Dynamic Models ◽  
Contact Forces ◽  
Lumped Parameter Model ◽  
Algebraic Equations ◽  
Continuum Robots ◽  
Modeling Approach ◽  
Lumped Parameter ◽  
Continuum Robot ◽  
Statics And Dynamics ◽  
Elastic Loading

This paper presents a novel modeling approach for the mechanics of multisegment, rod-driven continuum robots. This modeling approach utilizes a high-fidelity lumped parameter model that captures the variation in curvature along the robot while simultaneously defined by a discrete set of variables and utilizes the principle of virtual power to formulate the statics and dynamics of the continuum robot as a set of algebraic equations for the static model and as a set of coupled ordinary differential equations (ODEs) in time for the dynamic model. The actuation loading on the robot by the actuation rods is formulated based on the calculation of contact forces that result in rod equilibrium. Numerical optimization calculates the magnitudes of these forces, and an iterative solver simultaneously estimates the robot's friction and contact forces. In addition, modeling considerations including variable elastic loading among segments and mutual segment loading due to rods terminating at different disks are presented. The resulting static and dynamic models have been compared to dynamic finite element analyses and experimental results to validate their accuracy.

scholarly journals Continuous Backbone “Continuum” Robot Manipulators

ISRN Robotics ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-19 ◽  
Author(s):  
Ian D. Walker
Keyword(s):  
Dynamic Models ◽  
State Of The Art ◽  
Robot Manipulators ◽  
Complex Environments ◽  
Continuum Robots ◽  
Ongoing Research ◽  
Rigid Link ◽  
Future Developments ◽  
Current State ◽  
Continuum Robot

This paper describes and discusses the history and state of the art of continuous backbone robot manipulators. Also known as continuum manipulators, these robots, which resemble biological trunks and tentacles, offer capabilities beyond the scope of traditional rigid-link manipulators. They are able to adapt their shape to navigate through complex environments and grasp a wide variety of payloads using their compliant backbones. In this paper, we review the current state of knowledge in the field, focusing particularly on kinematic and dynamic models for continuum robots. We discuss the relationships of these robots and their models to their counterparts in conventional rigid-link robots. Ongoing research and future developments in the field are discussed.

A Regenerative Hydraulically Assisted Turbocharger System Model

2017 ◽  
Author(s):  
Tao Zeng ◽  
Devesh Upadhyay ◽  
Guoming Zhu
Keyword(s):  
Performance Measures ◽  
Hydraulic System ◽  
Hydraulic Turbine ◽  
Lumped Parameter Model ◽  
System Model ◽  
Model Complexity ◽  
Modeling Approach ◽  
Lumped Parameter ◽  
Turbocharging System ◽  
Parametric Relationships

A regenerative hydraulically assisted turbocharging system is introduced. A systematic modeling approach for the engine air-path influenced under the influence of the RHAT system is discussed. The proposed modeling approach adopted seeks to reduce model complexity by introducing simple parametric relationships between corrected performance measures and allows smooth extrapolation beyond available hydraulic turbine and pump maps. A lumped parameter model of the hydraulic system is presented. Model validation results are presented for an FTP-75 cycle.

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.

Continuum Manipulator Statics Based on the Principle of Virtual Work

2012 ◽  
Author(s):  
William S. Rone ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Numerical Method ◽  
Virtual Work ◽  
Lumped Parameter Model ◽  
Static Equilibrium ◽  
Principle Of Virtual Work ◽  
Single Segment ◽  
Gravitational Forces ◽  
Lumped Parameter ◽  
Continuum Robot ◽  
Continuum Manipulator

This paper presents a generalized method of determining the static shape conformation of a continuum robot based on the principle of virtual work. A lumped parameter model is utilized to model a prototypical single-segment manipulator. Elastic effects, gravitational forces and actuation loading are modeled as generalized forces and moments acting along the manipulators at discrete masses. A brief derivation of the governing static equations based on the principle of virtual work is presented, and then applied to the problem of continuum manipulator statics. The numerical method was successfully implemented numerically, capable of determining a system’s static equilibrium given a prescribed actuation.

scholarly journals Dynamic Modeling of a Spatial Cable-Driven Continuum Robot Using Euler-Lagrange Method

2020 ◽  
Vol 10 (1) ◽  
pp. 60-74
Author(s):  
Ammar Amouri ◽  
Chawki Mahfoudi ◽  
Abdelouahab Zaatri
Keyword(s):  
Dynamic Model ◽  
Dynamic Modeling ◽  
Dynamic Models ◽  
Model Development ◽  
Mathematical Expression ◽  
Gravitational Energy ◽  
Lagrange Method ◽  
Continuum Robots ◽  
Highly Nonlinear ◽  
Continuum Robot

Continuum robots are kinematically redundant and their dynamic models are highly nonlinear. This study aims to overcome this difficulty by presenting a more practical dynamic model of a certain class of continuum robots called cable-driven continuum robot (CDCR). Firstly, the structural design of a CDCR with two rotational degrees of freedom (DOF) is introduced. Then, the kinematic models are derived according to the constant curvature assumption. Considering the complexity of the kinetic energy expression, it has been approximated by the well-known Taylor expansions.  This case corresponds to weak bending angles within the specified bending angle range of the robot. On the other hand, due to the low weight of the CDCR components, the gravitational energy effects can be neglected compared to those stemmed from the elastic energy. Thereafter, the corresponding dynamic model is established using Euler-Lagrange method. Static and dynamic models have been illustrated by examples. This analysis and dynamic model development have been compared with the existing scientific literature. The obtained results shown that the consistency and the efficiency of accuracy for real-time have been carried out. However, the dynamic modeling of CDCR with more than 2-DOF leads to a more complex mathematical expression, and cannot be simplified by adopting the similar assumptions and methodology used in the case of 2-DOF.

Modeling the Human Body/Seat System in a Vibration Environment

2003 ◽  
Vol 125 (2) ◽  
pp. 223-231 ◽  
Author(s):  
Jacob Rosen ◽  
Mircea Arcan
Keyword(s):  
Human Body ◽  
Muscle Tension ◽  
Design Guidelines ◽  
Contact Forces ◽  
Lumped Parameter Model ◽  
Model Parameters ◽  
Apparent Mass ◽  
Human Dynamics ◽  
Lumped Parameter ◽  
Body Dynamics

The vibration environment is a common man-made artificial surrounding with which humans have a limited tolerance to cope due to their body dynamics. This research studied the dynamic characteristics of a seated human body/seat system in a vibration environment. The main result is a multi degrees of freedom lumped parameter model that synthesizes two basic dynamics: (i) global human dynamics, the apparent mass phenomenon, including a systematic set of the model parameters for simulating various conditions like body posture, backrest, footrest, muscle tension, and vibration directions, and (ii) the local human dynamics, represented by the human pelvis/vibrating seat contact, using a cushioning interface. The model and its selected parameters successfully described the main effects of the apparent mass phenomenon compared to experimental data documented in the literature. The model provided an analytical tool for human body dynamics research. It also enabled a primary tool for seat and cushioning design. The model was further used to develop design guidelines for a composite cushion using the principle of quasi-uniform body/seat contact force distribution. In terms of evenly distributing the contact forces, the best result for the different materials and cushion geometries simulated in the current study was achieved using a two layer shaped geometry cushion built from three materials. Combining the geometry and the mechanical characteristics of a structure under large deformation into a lumped parameter model enables successful analysis of the human/seat interface system and provides practical results for body protection in dynamic environment.

scholarly journals A Distributed Lumped Parameter Model of Blood Flow

2020 ◽  
Vol 48 (12) ◽  
pp. 2870-2886
Author(s):  
Mehran Mirramezani ◽  
Shawn C. Shadden
Keyword(s):  
Blood Flow ◽  
Lumped Parameter Model ◽  
Lumped Parameter
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