Poster_Project_Big_Bertha_Professor_Onal.ppt
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Transcript Poster_Project_Big_Bertha_Professor_Onal.ppt
Design and Manufacture of an Adaptive Suspension System
Michael Gifford (ME), Tanner Landis (ME/AE), Cody Wood (ME)
Advisors: Professor Cagdas Onal (RBE/ME), Siamak Ghorbani-Faal (RBE)
METHODOLOGY
ABSTRACT
This project focuses on the design, development, evaluation, and analysis of an adjustable vehicle
suspension system. This system is aimed to improve vehicle performance on all terrain conditions
from rough to flat surfaces. The proposed design is accomplished through the modification of a
double-triangulated four-bar linkage suspension. The modifications allow the upper links of the
suspension system to change vertical position on-the-fly, to meet operator preference. The position
change alters suspension geometry and therefore the performance characteristics of the vehicle;
specifically the anti-squat which impacts vehicle sag and therefore traction. Thus, traction is
directly controlled through adjustments to the suspension system. Through video motion analysis
of the modified and unmodified prototype vehicle, we determined the effect of the suspension
design. Future applications of this design are expected to improve the performance characteristics
of vehicles of all sizes ranging from mobile robots to automobiles. In addition to scalability, the
advantage of our design is the on-the-fly adaptability. This enables adjustments in suspension
performance for the terrain or obstacle being traversed.
UNIVERSAL
DESIGN
The initial design of the
universal system
LAB SCALE
PROTOTYPE
Purchase of a lab scale prototype that uses a
double triangulated 4 link suspension system
TEST AND
ANALYSIS
Unmodified
lab scale
prototype
FABRICATION
TEST AND
ANALYSIS
OBJECTIVE
•
•
•
Create an adaptive suspension system that •
•
can be retrofitted to various vehicles
•
“On-the-fly” adjustability through a user
interface
Variable anti-squat through the adjustment of •
the upper links
3D printing of components
and retrofitting to the lab
scale prototype
Anti-squat range of 35 – 170%
Utilize actuators to provide vertical motion
Motion should not allow suspension links to
bind
Must allow for immediate and exact
adjustments
Modified
lab scale
prototype
DESIGN
Our universal suspension system design for our lab scale prototype consisted of four major parts:
a slotted bracket, slide bracket, horizontal cross member and electrical rotational servos. These
parts were designed and fit to allow our prototype vehicle with a range of anti-squat between 35
and 172%.
• Charts were broken down into subsections to analyze the performance of the vehicle over a
number of obstacles and terrains
• The performance of the vehicle on various terrains was found to be dependent on the position of
the links
• The universal system provided immediate and exact vertical position change of the upper links of
the suspension through the use of the user interface
• Linkages do not bind at maximum wheel articulation, even with additional components added
• Plastic material was not ideal for the application due to the high torque of the motor
• Prototype motor was not accurately scaled; therefore there was more torque on the system than
would be present in a full scale model
Slotted Bracket
• Provides a track to guide the links vertical movement
• Designed to allow for ±0.15 inches of travel from center
• Slot was designed to have the same radius as the rotating link to
ensure a smooth travel surface
Slide Bracket
•
•
•
Slotted Bracket
Provides a connection point between the upper links and the
rotational servos
Designed to fit in the interior of the slotted bracket and provide a
secure connection between the links and the slotted bracket
Bracket was designed to rotate to avoid impedance by surrounding
surfaces and material
CONCLUSIONS
RESULTS
Slide Bracket
FUTURE PLANS
Horizontal Cross Member
•
•
It was determined that the universal system design improved the functionality of the prototype
vehicle over numerous terrains and obstacles. Although, one setting would not improve the
performance over all terrains, driver experience could be used to determine the best position for
any individual obstacle. The “on-the-fly” adaptability of the system provided the operator with a
means to make adjustments while traversing the terrain.
• Convert 3D printed prototypes to various materials dependent upon the application
• Apply the design to vehicles of all types
• Determine an efficient and cost effective design using different actuators that will provide digital
readout of link placement and anti-squat effect in comparison to the origin
Provides a connection point for the slotted bracket to the frame of the
vehicle
Designed to fit on top of the existing vehicle frame rails
Cross Member
ACKNOWLEDGEMENTS
Rotational Servo
•
•
The Project Big Bertha team would like to thank the Rapid Prototyping Team and Ming Luo for
their help with our project. We would also like to extend a very special thank you to our advisors
Professor Cagdas Onal and Siamak Ghorbani-Faal for their continued support throughout this
Project.
Used a Futaba S3003 Electric Rotational Servo
Connecting rod translates rotational motion from servo into vertical
motion of the upper links
Rotational Servo