Design and Manufacture of an Adaptive Suspension System

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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)
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. DESIGN Ou
r 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.
METHODOLOGY
The initial design of the universal system

• Purchase of a lab scale prototype that uses a
  double triangulated 4 link suspension system

Unmodified lab scale prototype

• 3D printing of components
• and retrofitting to the lab scale prototype

Modified lab scale prototype

• 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
• 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

• 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

Slotted Bracket

• Slide 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

RESULTS
Slide Bracket

• Horizontal Cross Member
• 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

• Rotational Servo
• Used a Futaba S3003 Electric Rotational Servo
• Connecting rod translates rotational motion from
  servo into vertical motion of the upper links

Rotational Servo