These Lego robots are based on the adorable Cheerleader Minifigure. They actually can dance to the beat of the music! Watch the video to see how that works.
About this creation
Enjoy this video. It’s a story about cute cheerleaders that turn out to be excellent engineers.
This adorable cheerleader belongs to the very first LEGO Collectable Minifigures. Unfortunatly she can’t dance. To bring her alive the robotic cheerleader “Mindy” is created. The robot is 9 times bigger than the Minifigure and loaded with Lego Mindstorms technology. After feedback on MOCpages the prototype went for a makeover to get more feminine looks.
Three cheerleader robots are created, each with a different hair cut. Together they form the team “First Robotic Cheerleaders” (FRC).
Each robot is balancing on only 2 wheels. A gyro sensor from HiTechnic (certified & sold by Lego) is used to detect unbalance. The Mindstorms NXT computer calculates the required power to the wheels, to prevent that the robot falls over.
With a weight of 1.3 kg & height of 35 cm it’s a big challenge to stay in balance. The fast dance moves make it even more difficult. Light weight construction techniques and a low point of gravity are used to get good performance.
The right arm is directly driven by a servo motor. A slip clutch with end stoppers is used for the left arm, which enables each robot to move both arms out of phase.
The cheerleaders are programmed in NXT-G (the standard NXT program language).
The software part for balancing is based on an algorithm by HiTechnic, that can be downloaded at www.hitechnic.com. Changes and extensions are mandatory to handle the robot mass & size. For instance, to deal with vibrations that occur due to play between the internal gears of the servo motors.
All dance moves are programmed in the cheerleaders memory. A position control system is developed to ensure that all cheerleaders dance in formation. Wheel displacements are measured and used to calculate the robot position and orientation on the dance floor. By means of a proportional algorithm the desired position and oriëntation of each robot is achieved.
Each robot applies a second external NXT computer to synchronize the dance steps to the beat of the music. Different songs & dances can be selected on the external NXT. Communication between the NXTs is by Bluetooth.
Video set with many Lego Factory buildings like the cool Pet Shop.