Effects of Center of Gravity (CoG) on Robot Design
Considering a Robot Design's Center of Gravity
The robot shown above is called Stack. It is a build designed from the V5 Competition Super Kit to compete in the 2019-2020 VEX Robotics Competition game Tower Takeover.
Notice where Stack's battery and brain are positioned. Notice that its manipulators are motored and can be lowered and raised as needed.
In order to design a competition-ready robot, the robot's design needs to be a stable one. That requires the team to consider where the robot's center of gravity is at all times. Raising a manipulator above a specific height should not risk having the robot tip - even at high speeds.
Motivate Discussion - Considering Center of Gravity within Designs
Q: Where is likely the worst place to position Stack's brain and battery? Why?
A: Anywhere at the top of the robot would be a bad idea. The lower positions help to keep the center of gravity low and stable.
Q: How might you prevent a robot's manipulator(s) from extending too far and risking the robot's stability?
A: You could use limit switches or other components to restrict the manipulator's range - at least when driving at high speeds.
Q: How should you test the stability of a competition robot?
A: Try controlling the robot at its maximum extended position to see which speeds risk unstable performances. If even reasonably low speeds risk having the robot tip, the robot's design should be reviewed and components may need to be shifted around