- Building Smart LEGO MINDSTORMS EV3 Robots
- Kyle Markland
- 161字
- 2021-08-27 19:17:33
Rotation
The tank also needs to be able to aim at the beacon. The entire turret assembly is mounted on a turntable, which allows it to rotate to the right and left. The turntable is powered by an EV3 medium motor, which is plugged into port D:
![](https://epubservercos.yuewen.com/3D99B5/19470395308895206/epubprivate/OEBPS/Images/0a51692e-4f48-4399-89d1-6cd73e6492e9.png?sign=1739049683-tRuDmY8UGiYCnTNxpU1AAUkfU7i9fxl1-0-05c9385469e59320bdc306a601116f98)
This motor is located in the back of the robot to the right side. It sends its power through a 90-degree gear connection, which is very similar to the one used with the cannons. However, there is another set of gears in this mechanism: a 24-tooth gear drives the gear on the turntable mechanism. The overall gear ratio between the motor and the turntable is 4.17:1, meaning the motor must make 4.17 rotations to get the turret to rotate a full 360 degrees. This is a much slower gear ratio than the one we saw on the cannon. Slowing down the rotation of the turret makes its motion more accurate and easier to control:
![](https://epubservercos.yuewen.com/3D99B5/19470395308895206/epubprivate/OEBPS/Images/f56046ee-38a6-4aa9-8cb3-4c1739a3c030.jpg?sign=1739049683-lyLnJGlQGid8vkkLxh51jl9dkhGJJdUh-0-ffe20172e4550a86a8db37a2c0a4ed55)