VEX Center of Gravity
J.M. Gabrielse
Center of Gravity
The center of gravity is the average mass
and position of all the pieces that make up a
robot.
J.M. Gabrielse
Robots tip over all the time!
Build your robot so the center of gravity
stays between the wheel axles and
your robot won’t tip over. J.M. Gabrielse
Find the Center of Gravity
Hang any object from a string:
The object will rotate until the center of gravity lines up
with the string.
• Hang the robot from a string and mark the line.
• Tie the string to a different points and repeat.
The center of gravity is where the lines cross.
J.M. Gabrielse
J.M. Gabrielse
J.M. Gabrielse
J.M. Gabrielse
The Center of Gravity
Is Where the Lines Cross
J.M. Gabrielse
Tipping
Robots tip if the center of gravity isn’t
between the wheels.
J.M. Gabrielse
Robot Arm
• Pick something up and the center of
gravity moves
J.M. Gabrielse
Robot Tips
Keep heavy items:
• close to the ground
• in the middle of the robot
The protobot’s battery and arm balance each other
out to keep the center of gravity in the center of
the robot.
J.M. Gabrielse
Your Turn
Where is the center of gravity?
What happens to a robot if the center of
gravity isn’t between the wheels?
How can you make a robot less tippy?
J.M. Gabrielse
Resources
• Inventor’s Guide: 2·7 - 2·11
J.M. Gabrielse
Resources
• http://www.education.rec.ri.cmu.edu/roboti
cscurriculum/vex_online/lessons/mechanic
s/center_of_mass/mechanics_center_of_
mass.html
• Inventor’s Guide: 2·7 - 2·11
J.M. Gabrielse