Acrobots

The robot must learn to oscillate back and forth, increasing its arc until it has enough speed to reach the top.

Unlike a standard robotic arm where every joint has its own motor, the Acrobot has only one powered joint. It consists of two links and two joints: Acrobots

In the field of robotics, the Acrobot is a benchmark for testing and nonlinear control algorithms. Developers use it to answer a critical question: How can a machine learn to perform a task when it doesn't have direct control over its primary pivot point? The robot must learn to oscillate back and

This joint is powered (active). By moving this single joint, the robot must generate enough momentum to swing its entire body upward. Developers use it to answer a critical question:

Once at the peak, the Acrobot must perform a "handstand" on its passive joint. This requires constant, minute adjustments at the elbow to maintain a precarious equilibrium. Why Do We Build Them?

Because the first joint has no motor, the robot is . It cannot simply "lift" itself; it must use precisely timed "kicks" at the elbow to build up energy, eventually swinging into an inverted vertical position—a feat known as the "swing-up" task. The Challenge of Control