Design of a Mars Rover with High Stability Margin on Rough Terrain

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Design of a Mars Rover with High Stability
Margin on Rough Terrain
Prof.Dr.Tech.Sci Rasim ALIZADE, Firat
BARLASMaster of Science Thesis in Mechanical
Engineering Izmir Institute of Technology,
Izmir - TURKEY
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WHAT DOES ROVER MEAN ?

• Mobile Vehicles which works on rough terrain
  called Rover.

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WHERE ROVERS BEING USED ?

• Mines
• Disaster areas (ie. Earthquake)
• Dangerous building investigations (i.e Nuclear
  Plants)
• Planetary Exploration (i.e. Mars Missions)
• Pipelines

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ADVANTAGES OF ROVERS

• Very Light (10 - 20 kgs)
• Can work at extreme temperatures and radiation
• Can enter small piplines

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MARS ROVERS

• First planetary exploration rovers were designed
  in second half of 20th century for researches on
  Moon. Russian Lunakhod rover was the first rover
  that has been to another celestial body except
  Earth. After Apollo projects in 1968 - 1972
  rovers became less popular till 1996.

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SOJOURNER
First Rover on Mars!
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SOJOURNER

• On July 4, 1997, the Mars Pathfinder spacecraft
  successfully landed on Mars and deployed an 11.5
  kg microrover Sojourner. This microrover
  accomplished its primary mission objectives in
  the first 7 days and continued to operate 83 Mars
  days.

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SOJOURNER MOBILITY SYSTEM

• 6 Wheels with actuators (DC Motors)
• 4 wheels has steering motors (Servo Motors)
• Wheels are connected with two symmetric planar
  mechanisms

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MECHANISM FREE BODY DIAGRAM
ROCKER
BOGIE
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JOINT DISTRIBUTION
R JOINT
R JOINT
R JOINT
R JOINT
R JOINT
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ADVANTAGES OF ROCKER - BOGIE
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ADVANTAGES OF ROCKER - BOGIE
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ADVANTAGES OF ROCKER - BOGIE
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DISADVANTAGES OF ROCKER - BOGIE
From the quasi-static force analysis,
Rocker-Bogie demonstrates the better performance,
due to the well-distributed weight over all
wheels and thus resulting in more constant
traction forces. However, when climbing up a
steep inclined surface, Rocker-Bogie front wheels
may lose contact at lower slope . This is due to
the influence of moment produced by traction
forces of the middle wheels. From the experiment,
the vehicle using Rocker-Bogie suspension can
travel across obstacle, such as vertical wall and
rock for some degrees of difficulty, due to the
property of the suspension, which passively adapt
to the terrain.
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FUNDAMENTAL RESULTS FOR NEW DESIGNS
After all these results, we can reach an
agreement on some important ideas.

• At least 2 DOF for wheel connections
• More than 3 points contact with ground
• Wheels must be connected to each other to
  distribute the load efficiently

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NEW DESIGN...
According to investigations of Rocky mobility
system, we decided to increase the stability of
the rover by using Parallel Manipulator system.
Active controller will determine the center of
gravity by using rate-gyro. The moving platform
will re-configure itself. For high-speed usage,
modified double-Chebishev mechanism is very
eficient.
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Contact...
For rover project rasimalizade_at_iyte.edu.tr fira
t_at_macrolimit.com For other projects
www.iyte.edu.tr
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THANK YOU FOR YOUR PATIENCE !!!