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

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? The robot must learn to oscillate back and

The Acrobot: Balancing Science and Skill The "Acrobot"—a portmanteau of "acrobatic" and "robot"—is a fascinating classic in the world of control theory and robotics. It is a two-link, underactuated planar robot designed to mimic the movement of a gymnast swinging on a high bar. While it may look simple, the Acrobot represents one of the most significant challenges for engineers and roboticists: mastering complex movement with limited control. What Makes an Acrobot Unique? This requires constant, minute adjustments at the elbow

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

This joint is powered (active). By moving this single joint, the robot must generate enough momentum to swing its entire body upward.