University of California - Santa Cruz Feb 19 2026 Imagine balancing a ruler vertically in the palm of your hand: you have to constantly pay attention to the angle of the ruler and make many small adjustments to make sure it doesn't fall over. It takes practice to get good at this.  In engineering, this is called the "inverted pendulum" or "cart-pole" problem, in which a control system learns to balance an upright pole hinged to a moveable cart. This problem is used as a benchmark in fields like