Mechanical Analysis of Snake-Like Robot for Colonoscopy

2013 ◽  
Vol 706-708 ◽  
pp. 849-854
Author(s):  
Xiao Xiao Feng ◽  
Fu Bing Jiang ◽  
Hai Yan Hu ◽  
Hong Gu ◽  
Xiao Wei Cai ◽  
...  
Keyword(s):  
Cantilever Beam ◽  
Mechanical Model ◽  
Mechanical Analysis ◽  
Mechanical Structure ◽  
Force Diagram ◽  
Single Section ◽  
Bending Process ◽  
Continuum Structure

In order to develop a robot for colonoscopy, which can provide the same functions as conventional colonoscope, but much less pain and discomfort for patient, a snake-like robot with continuum structure is proposed. The mechanical structure of snake-like robot for colonoscopy is introduced and the angle of single section is calculated. The mechanical model of cantilever beam is built, the force diagram is drawn and the mechanical analysis of single section in bending process is mainly analyzed. Finally, ‘Pro/E’ is used to build model and simulate the process that the snake-like body goes through the colon. This paper lays foundation for the research on snake-like robot for colonoscopy.

Dynamic obstacle-surmounting analysis of a bilateral-wheeled cable-climbing robot for cable-stayed bridges

2019 ◽  
Vol 46 (3) ◽  
pp. 431-443 ◽  
Author(s):  
Fengyu Xu ◽  
Quansheng Jiang
Keyword(s):  
Dynamic Analysis ◽  
Mechanical Analysis ◽  
Climbing Robot ◽  
Obstacle Crossing ◽  
Content Type ◽  
Mechanical Structure ◽  
Dynamic Obstacle ◽  
The Stability ◽  
Rod Structures ◽  
Moving Path

Purpose Field robots can surmount or avoid some obstacles when operating on rough ground. However, cable-climbing robots can only surmount obstacles because their moving path is completely restricted along the cables. This paper aims to analyse the dynamic obstacle-surmounting models for the driving and driven wheels of the climbing mechanism, and design a mechanical structure for a bilateral-wheeled cable-climbing robot to improve the obstacle crossing capability. Design/methodology/approach A mechanical structure of the bilateral-wheeled cable-climbing robot is designed in this paper. Then, the kinematic and dynamic obstacle-surmounting of the driven and driving wheels are investigated through static-dynamic analysis and Lagrangian mechanical analysis, respectively. The climbing and obstacle-surmounting experiments are carried out to improve the obstacle crossing capability. The required motion curve, speed and driving moment of the robot during obstacle-surmounting are generated from the experiments results. Findings The presented method offers a solution for dynamic obstacle-surmounting analysis of a bilateral-wheeled cable-climbing robot. The simulation, laboratory testing and field experimental results prove that the climbing capability of the robot is near-constant on cables with diameters between 60 and 205 mm. Originality/value The dynamic analysis method presented in this paper is found to be applicable to rod structures with large obstacles and improved the stability of the robot at high altitude. Simulations and experiments are also conducted for performance evaluation.

Investigation on Friction Conditions during a Severe Bending Deformation on a Thick Plate

2016 ◽  
Vol 716 ◽  
pp. 176-183
Author(s):  
Antonello D'Annibale ◽  
Mohamad El Mehtedi ◽  
Antoniomaria Di Ilio ◽  
Filippo Gabrielli ◽  
Lorenzo Panaccio
Keyword(s):  
Mechanical Properties ◽  
Mechanical Model ◽  
Thick Plate ◽  
Low Carbon Steel ◽  
Experimental Tests ◽  
Stress And Strain ◽  
Low Carbon ◽  
Bending Process ◽  
Steel Aisi ◽  
Machining Operations

In this paper, the friction behaviour in a severe bending process of a thick plate was investigated, taking into account both dry and lubricated conditions. Early experimental tests were performed to obtain mechanical properties of the low carbon steel AISI 1006, to be used as input in FE solver. Besides a 3D thermo-mechanical model based on FEM was developed to predict stress and strain distributions and final component dimensions. The second experimental series was composed of a coining process and a forming operation to reach the size of the final part. The analysis and the control of the friction conditions has permitted to obtain a product of higher quality that permitted to avoid all the secondary machining operations previously required.

scholarly journals Study on Overburden Stability and Development Height of Water Flowing Fractured Zone in Roadway Mining with Cemented Backfill

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yu Dong ◽  
Yucheng Huang ◽  
Jifang Du ◽  
Fei Zhao
Keyword(s):  
Empirical Formula ◽  
Mechanical Model ◽  
Fractured Rock ◽  
Coal Pillar ◽  
Main Roof ◽  
Mechanical Analysis ◽  
Overburden Rock ◽  
Fractured Zone ◽  
The Stability ◽  
Rock Beam

In order to explore the stability of overburden rock and the development height of water flowing fractured zone in roadway filling mining, based on the movement and deformation mechanism of overburden rock, the mechanical analysis of overburden stability and failure was carried out, and the mechanical model of main roof rock beam was established, and the ultimate span and limit deflection of rock beam fracture were deduced. Combined with the mechanical model of the main roof fractured rock, the basis for the judgment of overburden failure developing to fractured zone is given in this paper. Taking a coal mine roadway backfill under water-bearing stratum as an example, based on the equivalent mining height, the theoretical calculation and analysis are carried out on the stability of overburden rock and the height of water flowing fractured zone. The reliability of the theoretical analysis is verified compared with the empirical formula and the numerical simulation results. The results showed that the water flowing fractured zone developed to the bottom of no. 7 glutenite, with a height of 32.5 m, slightly less than the calculation result of the empirical formula. The thickness of the waterproof coal pillar was 39.8 m, which was much less than the distance from the aquifer to the coal seam and can be mined safely.

Mechanical Model and Movement Analysis of Self-Adjusting Bolt in Converter

2014 ◽  
Vol 488-489 ◽  
pp. 1070-1073
Author(s):  
Qiang Yin ◽  
Gong Fa Li
Keyword(s):  
Stress Analysis ◽  
Dynamic Load ◽  
Mechanical Model ◽  
Movement Analysis ◽  
Mechanical Analysis ◽  
Model Analysis ◽  
The Self ◽  
Maximum Torque ◽  
Movement Model ◽  
Bolt Support

The movement model of self-adjusting bolt is built in this paper, then the kinematical and mechanical analysis is taken to determine the movement of bolt under the converters working condition.Via the mechanical model analysis of self-adjusting bolts, the load applied to the self-adjusting bolt support including the static weight load of converter and steel liquid, the tilting torque, the dynamic load produced by frequent startup, brake, impact, and the boiling of steel liquid is calculated to determine the distribution of load forcing on the three groups of the self-adjusting bolt. According to the results of stress analysis, the bolt facing tapping hole is the most dangerous when converter tilts 63°. The maximum torque is 281.5101tm.

Theoretical and Experimental Study on Crystal Detachment from a Chilling Surface with Vibration

2014 ◽  
Vol 490-491 ◽  
pp. 172-176
Author(s):  
Wen Li Wang ◽  
Rui Zhao Xu ◽  
Xue Jun Chang
Keyword(s):  
Experimental Study ◽  
Solid Surface ◽  
Vibration Frequency ◽  
Mechanical Model ◽  
Theoretical Study ◽  
Mechanical Analysis ◽  
Primary Phase ◽  
Experimental Results ◽  
Cooling Temperature ◽  
Main Factors

A model of crystal detachment from a chilling solid surface with vibration has been presented according to the mechanical analysis of the primary phase of a growing crystal grain. The model indicates that the main factors of crystal detachment are vibration frequency and amplitude as well as cooling temperature of the chilling solid surface. The effects of the above three factors on the actual crystal detachment behaviors were studied experimentally by using a transparent NH4Cl-70%wtH2O alloy. The consistency between the experimental results and theoretical study proves the mechanical model.

Numerical Simulation on the Laser Bending of Thin Wall Tubes

2011 ◽  
Vol 460-461 ◽  
pp. 798-801 ◽  
Author(s):  
Nan Hai Hao ◽  
Yu Ling Gai
Keyword(s):  
Process Parameters ◽  
Three Dimensional ◽  
Mechanical Analysis ◽  
Outer Diameter ◽  
Thin Wall ◽  
Laser Bending ◽  
Cross Sectional ◽  
Bending Process ◽  
Mechanical Bending ◽  
The Cost

Laser tube bending is a spring-back-free noncontact forming method that has received considerable attention in recent years. Compared to mechanical bending, no hard tooling, dies, or external force is used in laser bending, thus the cost is greatly reduced for small-batch production and prototyping. Some quality issues, such as cross sectional distortion and intrados protrusion exist in laser bending and have growing tendency when the tube’s wall being thinner. This paper investigates the effects of process parameters on the deformation of thin wall tube through numerical simulations and experiments. The dimensions of the tube analyzed are 32 mm in outer diameter and 0.48mm in wall thickness. A three-dimensional transient thermo-mechanical analysis using the finite element method is carried out to simulate the laser bending process with some results validated by experiments. The effects of process parameters on the deformation of thin wall tubes are discussed in detail.

Theoretical and Experimental Identification of Clearance Nonlinearities for a Continuum Structure

2016 ◽  
Vol 11 (4) ◽  
Author(s):  
Jie Liu ◽  
Bing Li
Keyword(s):  
Cantilever Beam ◽  
Piecewise Linear ◽  
Influence Factors ◽  
Piecewise Linear Function ◽  
Continuous Systems ◽  
Displacement Curve ◽  
Engineering Structures ◽  
Fitting Method ◽  
Nonlinear Force ◽  
Continuum Structure

Clearance is unavoidable in many engineering structures due to the manufacturing and installation errors. These clearances can cause intense impact and wear of the contacting pairs, which may change the dynamic response and eventually reduce the movement precision and the service life of the transmission system. Parameters identification of the clearance would provide better understanding of dynamic behaviors of the clearance and contribute significantly for the control of the induced disturbance and deviation. In this paper, based on dynamic characteristics of the clearance nonlinearity, the piecewise fitting method is first proposed to identify the clearance value of the continuum structure. During the proposed method, first, the rough scope of the clearance value extracted from the displacement response is divided into subintervals. And then, the nonlinear force is fitted by the piecewise linear function in the subintervals. Once the equivalent stiffness is obtained, the clearance value can be calculated by the sorting nonlinear force–displacement curve. The feasibility of the piecewise fitting method was verified by a cantilever beam system with clearances in simulation. Besides, some influence factors of this identification method, including the clearance value, exciting force level and measurement noise, are fully discussed to illustrate the robustness of this method. Moreover, an experiment system of a cantilever beam with adjustable clearances was designed to experimentally validate the effectiveness of the proposed method, and the results show that the piecewise fitting method can precisely identify the clearance value of continuous systems.

Large Deflection of a Non-Linear, Elastic, Asymmetric Ludwick Cantilever Beam

2010 ◽  
Author(s):  
Alberto Borboni ◽  
Diego De Santis ◽  
Rodolfo Faglia
Keyword(s):  
Cantilever Beam ◽  
Cross Section ◽  
Mechanical Model ◽  
Elastic Moduli ◽  
Large Deflection ◽  
Neutral Surface ◽  
Linear Elastic ◽  
Non Linear ◽  
Vertical Displacements ◽  
Tension And Compression

The investigated cantilever beam is characterized by a constant rectangular cross-section and is subjected to a concentrated vertical constant load at the free end. The same beam is made by an elastic non-linear asymmetric Ludwick type material with different behavior in tension and compression. Namely the constitutive law of the proposed material is characterized by two different elastic moduli and two different strain exponential coefficients. The aim of this study is to describe the deformation of the beam neutral surface and particularly the horizontal and vertical displacements of the free end cross-section. The analysis of large deflection is based on the Euler-Bernoulli bending beam theory, for which cross-sections, after the deformation, remain plain and perpendicular to the neutral surface; furthermore their shape and area do not change. On the stress viewpoint, the shear stress effect and the axial force effect are considered negligible in comparison with the bending effect. The mechanical model deduced from the identified hypotheses includes two kind of non-linearity: the first due to the material and the latter due to large deformations. The mathematical problem associated with the mechanical model, i.e. to compute the bending deformations, consists in solving a non-linear algebraic system and a non-liner second order ordinary differential equation. Thus a numerical algorithm is developed and some examples of specific results are shown in this paper. Precisely, the proposed problem is a generalization of similar cases in literature, consequently numerical comparisons are performed with these previous works, i.e. assuming linear elastic materials or assuming symmetric Ludwick type material with same behavior in tension and compression like aluminum alloy and annealed copper. After verifying a proper agreeing with the literature, in order to investigate the effect of the different material behavior on the horizontal and vertical displacements of the free end cross-section, numerical results are obtained for different values of elastic moduli and strain exponential coefficients. The arising conclusions are coherent with the assumed hypotheses and with similar works in literature.

Study on Design Method of Non-Uniform Beam of Mechanical Structure

2012 ◽  
Vol 479-481 ◽  
pp. 2568-2571
Author(s):  
Guo Zhi Zhang
Keyword(s):  
Cantilever Beam ◽  
Design Method ◽  
New Method ◽  
Mechanical Structure ◽  
Uniform Beam ◽  
Beam Design ◽  
Mechanical Models ◽  
Typical Parameter

The non-uniform equivalent beam design method for non-uniform beam of mechanical structure was proposed. Its equivalent mechanical models of tension or compression and bending was established. Moreover, the erro between the result of FEM and the result of non-uniform equivalent beam design method is less than 5% so as to verify the accuracy of non-uniform equivalent beam design method for typical parameter bending cantilever beam and the tension link. The study in the paper provides a new method and basis for design and calculation of similar mechanical structures.

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