Robotic Punching Arm
Puncher battles are a fun classroom activity that guarantee that students will innovate to win! By tuning the bar lengths of their puncher's 4-bar linkage, students can take advantage of "inverse leverage" to throw fast punches to knock their opponent's block off.
Before Finishing Your Build, Tune Bar Lengths to Optimize for Punching
The above bar ratio of 2:4 means the fist's speed and distance traveled increases significantly
We'll Build a Puncher in Stages, Starting With Bar 2
Here Are the LEGO Technic Parts Used
Assemble Bar 2
Assemble Bar 1 (the Handle), and Add Bar 3
Be sure to use the yellow frictionless pins for joints designed to move!
Add Bar 4
Add a "Block" for Your Opponent to Knock Off
Optional: Motorized Punchers
Punchers can also be motorized to make "battle bots". This can be done by programming a servo motor to do a partial rotation, or by adding a crank and a 6th bar as is done in the video above.