NXT Ice Skater
Project Summary
Our ice skater simulates the change in rotational speed when ice skaters extend or tuck in their arms.
Project Description
Ever wondered why ice skaters spin faster when they tuck in their arms? We built a robot to do the same thing. Using a Vernier Rotary Motion Sensor, we were able to measure the velocity of the spinning robot with its arms outwards and pulled inwards. As the robot pulled its arms in, its velocity increased.
Next, we wanted to see if we could build a robot that could keep constant angular velocity. This robot compensates for slowing down due to friction by adjusting the height of its arms. Using a Vernier Low-g Accelerometer mounted on the front of the robot, facing outwards, the robot could measure its centripetal acceleration. By maintaining a constant angular acceleration, the robot has constant velocity.
We connected the Vernier Rotary Motion Sensor to a LabPro and viewed the flat velocity graph on a computer with Logger Pro. Once the ice skater's arms are as close inwards as possible, the ice skater is unable to maintain constant velocity. This drop in velocity is easily noticable on the graph.
In a control test, we spun the robot without running the program. Its velocity slowly decreased.
Demo Movie
Project Downloads
- Download the NXT Ice Skater MINDSTORMS NXT program »
- Download the NXT Ice Skater building instructions (HTML format) »
- Download the NXT Ice Skater building instructions (LEGO digital designer format) »
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