design and fea based vibration characteristic analysis of ... · considered rocker bogie mechanism....

Design and FEA Based Vibration Characteristic Analysis of Rocker

Bogie Mechanism

Vishvajeet

B.Tech student, Department of Mechanical Engineering,

Dev Bhoomi Institute of Technology,

Dehradun, Uttrakhand, India.

Faraz Ahmad

Assistant professor, Department of Mechanical Engineering,



Pankaj Singh




Ravindra singh




ABSTRACT A rocker bogie mechanism is a vehicle in which the

mechanisms balance the Bogie at different ground

conditions. Rockers bogie mechanism is generally

used by space research companies for space

exploration. Now days it has application in various

fields like; military, spy vision at hilly areas etc. This

type of moving vehicle was subjected to vibration. So

the present study deals with the modeling of the

rocker bogie mechanism, which was design by Catia

software and analyzed by Ansys 14.0. The failure

frequency range was determined by changing the

boundary condition of the considered rocker bogie

mechanism. First six failure frequencies were

calculated by modal analysis. Furthermore the model

was analyzed for static lording condition. The

simulation result was under safety limit and can

sustain the failure criteria.

Keyword: Rocker mechanism, vibration, CAD

model, failure range.

Introduction

In Rocker Bogie Mechanism, The term Rocker

denotes the links of the mechanism. There was six

links at both side of the mechanism and balanced the

Bogie in the moving condition. To maintain the

center of gravity of the vehicle, one link or rocker of

the rocker bogie mechanism moves upward and the

other rockers goes downward. One side of the rocker

was connected to the drive wheel the other end

connected to the bogie and the relative movement

provides the required motion and degree of freedom

to the rocker bogie mechanism. Many researchers

work on the dynamic modeling and control of the

rocker mechanism like:

Rockers bogie mechanism becomes the NASA’s

most favorite design of wheel robot, the main

problem with this mechanism is its low average

operating speed, places where the large flat surface is

needed to cover in short time interval this mechanism

becomes not suitable mechanism, mainly due to its

stability problems [1-4].

Nitin Yadav et. al. have studied about the places,

where the gravitational coefficient remains lower

than the earth, at this place available suspension

system not gives the required results as the shock

absorbing or among the changes. To oppose this anti

gravity effect, Jet Propulsion Laboratory and NASA

introduced a mechanism called the rocker bogie

mechanism. It is generally a suspension system

basically used in mechanical robotics vehicles for the

space explorations .This suspension based mars rover

International Journal of Applied Engineering Research ISSN 0973-4562 Volume 14, Number 9, 2019 (Special Issue) © Research India Publications. http://www.ripublication.com

Page 209 of 214

mechanism is firstly introduced for the Mars Path

finder, Mars Exploration and for Mars Science

Laboratory mission. The motive this research is to

understand the mechanical design [5].

Brian D. el. al. has designed the rocker bogie

mechanism for slow speed. It is able to climb the

obstacles that are of the size of a wheel. When

obstacle comes, the vehicles motion effectively stops

and the front wheels climbs the obstacles at a low

speed [6].

Material properties and Finite Element

Analysis

In present study the CAD model was designed by

Catia and the model was tested by PVC material. this

material was good in strength for light weight

application like; photography. PVC material has 1,45

g/cm3 of density, 580 Mpa modulus of elasticity and

0.4 Poisson’s ratio. Figure 1 and 2 shows the 3-D

model and mesh model of the rocker bogie

mechanism respectively.

Figure 1: Rocker Bogie CAD model

Figure 2: Rocker Bogie Mesh model

Figure 3: Base fixed boundary condition

Figure 4: Axel fixed boundary condition

The main objective of this study was to find out the

resonance frequency of the considered bogie

mechanism. The modal analysis was carried out for

first six mode shape and the corresponding

deformation was calculated. By analyzing the model

with different fixed boundary condition the modal

analysis give the range for failure.


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Simulation Result

Base fixed boundary condition result

Figure 5: Mode shape for based fixed boundary condition


Page 211 of 214

Axel fixed boundary condition result

Figure 6: Mode shape for Axel fixed boundary condition


Page 212 of 214

Figure 7: first six mode frequency comparison

Figure 8: First six mode Total Deformation

comparison

Static structural analysis

The CAD model of the rocker bogie mechanism was

fixed at wheel axel as shown in figure 4. Furthermore

a static loading of 50 N was applied as shown in

figure 9, to check the static behavior.

Figure 9: Applied loading condition

The result of total deformation, stress and strain due

to 50 N loading was demonstrated in figure 10 to 12,

respectively.

Figure 10: Total deformation

Figure 11: Equivalent Stress

Figure 12: Equivalent Strain

Conclusion

The solid structure of the rocker bogie mechanism

was designed for analysis. The two different

boundary conditions were selected for the analysis to

determine the failure range. From the 7 we can see

that the failure frequency in fixed axel was less as

0

200

400

600

800

1000

1 2 3 4 5 6

Modeshape

Based fixedcondition

Axel fixedcondition

NaturalFrequency

0

100

200

300

400

500

600

700

800

900

1 2 3 4 5 6

Modeshape

Based fixedcondition

Axel fixedcondition

Total Deformation


Page 213 of 214

compare to the base fixed condition frequency. That

way 203.9Hz was the fundamental frequency of the

considered Rocker bogie mechanism. Furthermore

the result of the deformation, stress and strain was

under satisfactory condition. We can say that the

design is safe under light loading (50 N) condition.

References

[1] Hong-an Yang at al., Dynamic Rocker-Bogie: A

Stability Enhancement for High-Speed Traversal

International Journal of Robotics and Automation

(IJRA) Vol. 3, No. 3, September 2014, pp.

212~220 ISSN: 2089-4856

[2] A. Bhole, S. H. Turlapati, Raja shekhar V. S, J.

Dixit, S. V. Shah, Madhava Krishna K, “Design

of a Robust Stair Climbing Compliant Modular

Robot to Tackle Overhang on Stairs”

arXiv:1607.03077v1 [cs.RO], 11 Jul 2016.

[3] Dongkyu Choi at al., „Analysis method of

climbing stairs with the rocker-bogie

mechanism‟ , „Journal of Mechanical Science

and Technology‟ vol.27,issue 9 ,pp 2783-

2788,2016

[4] Brian D. Harrington and Chris Voorhees, The

Challenges of Designing the Rocker-Bogie

Suspension for the Mars Exploration Rover,

Proceedings of the 37th Aerospace Mechanisms

Symposium, Johnson Space Center, May 1921,

2004.

[5] Yadav, N., Bhardwaj, B., & Bhardwaj, S. (2015).

Design analysis of Rocker Bogie Suspension

System and Access the possibility to implement

in Front Loading Vehicles. IOSR Journal of

Mechanical and Civil Engineering (IOSR-JMCE),

12(3), 64-67.

[6] Brian D. Harrington and Chris Voorhees, The

Challenges of Designing the Rocker-Bogie

Suspension for the Mars Exploration Rover,

Proceedings of the 37th Aerospace Mechanisms

Symposium, Johnson Space Center, May 1921,

2004.


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