Control of a furuta pendulum

The Furuta pendulum is depicted in Fig. 15.1. Controlling the Furuta pendulum may be described by referring to the old trick known as the broomstick-balancing problem. In a Furuta pendulum, the person’s arm is replaced by a beam technically known as the arm, which receives the torque generated by a permanent magnet brushed direct current motor at one of its ends. Hence, the arm can only move on a horizontal plane such that its other end describes a circumference. At this end another beam is placed, technically known as the pendulum, which joins to the arm by means of some bearing allowing the pendulum free movement. This means that no motor is placed at this joint. However, the bearing in this place constrains the pendulum to only move by rotating on a plane that is orthogonal to the arm. This means that the pendulum’s free end can only describe a circumference whose center is placed at the point where the arm and the pendulum join.