Center of Gravity Locator
List what is on the robot and where, and find out where its balance point actually sits. Feeds straight into the tipping calculator.
Inputs
Measure from the back left corner, at floor level.X across to the right, Y forwards,Z upwards. Any consistent origin works, since only the relationships matter.
Results
Total weight
—lb
CG height above floor
—in
The number the tipping calculator wants.
CG across (X)
—in
CG along (Y)
—in
Components listed
—
Biggest single contributor
—
Where it lands
Looking down on the robot from above. The cross is the balance point, the dashed lines are the middle of the frame, and each circle is one of your parts, sized by how heavy it is. A CG well off center means the robot leans that way and tips more easily towards it.
Left to right, matching the X measurements you entered above.
Front to back, matching your Y measurements.
How this is calculated
The center of gravity is the weighted average position of everything on the robot. Each component pulls the balance point towards itself, in proportion to how heavy it is:
CG = Σ(weight × position) ÷ Σ(weight)With your numbers
Applied separately to each axis. A heavy thing far out moves the CG a lot; a light thing far out barely moves it at all. That product of weight and distance is the whole story.
Why the height is the number that matters
X and Y tell you whether the robot is balanced left-to-right and front-to-back, which is worth checking. But Z is the one that decides whether you tip over. A robot resists tipping in proportion to how far its CG sits horizontally from the wheels it would pivot over, and against how high that CG is. Raising the CG makes every tipping threshold worse at once: under acceleration, under braking, and in a turn.
This is why a tall scoring mechanism costs you more than its weight suggests, and why the battery is worth mounting low even though moving it is a nuisance.
Checking it against the real robot
You can measure the CG height directly and it is worth doing once. Balance the robot on a thin edge, such as a length of aluminum, and the balance point is directly under the CG in that direction. Do it along the robot and across it and you have X and Y measured rather than calculated.
Height is harder without tilting the robot, which is exactly why it is the one worth calculating here.
Sources & assumptions
No VEX-specific data is used on this page. The result follows from your own measurements and the definition of a weighted mean, so there is nothing here to go stale between seasons.
Assumes each component is concentrated at the single point you give it. For compact things that is fine. For something long and heavy, like a full drivetrain or a tall lift, either use its own midpoint or split it into two entries at either end.
Save this run, and compare
Keeps what is on screen so you can change something and see both sides of the change. Saved in this browser only, never uploaded.
Make a notebook page
Turns this calculation into a dated engineering notebook page: the setup, data, results, figures, working and sources, numbered and cited. You add the goal, the decision and the reflection in your own words, plus photos and sketches. Print it, paste it into Google Docs, or download a Word file or slides.
Where this goes next
Explore further on the full mapWhere the answers on this page can be used, and which tools could have given you the numbers it asks for.
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Center of Gravity Locator
Where your answer goes
Tipping & Wheelie Thresholdfind out how much acceleration or slope tips a robot with that CGbrings your center of gravity height with itPushing Force & Traction Limitsee how much grip that weight gives you for pushingbrings your robot weight with itAcceleration & Time-to-Speedsee how that weight slows the robot getting up to speedbrings your robot weight with itWhole Robot Design Checkcheck weight and CG against every other limit at oncebrings your robot weight with ita number carries across the next question it raises