J.M. Gabrielse

VEX Center of Gravity

J.M. Gabrielse

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 GravityIs 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/roboticscurriculum/vex_online/lessons/mechanics/center_of_mass/mechanics_center_of_mass.html

• Inventor’s Guide: 2·7 - 2·11