Linear motor driven double inverted pendulum: A novel mechanical design as a testbed for control algorithms

The inverted pendulum is a classic experimental facility that is widely used as a benchmark for testing control algorithms. One of the difficulties, however, with the traditional inverted pendulum is that it is not a very challenging problem to compare modern control techniques. In addition, it is usually driven by a rotary motor and transmission system that introduces mechanical friction forces as well as periodic and aperiodic disturbances which result in the pendulum performance not as repeatable as desired. In particular, this lack of repeatability, which is very difficult to model, makes the use of this traditional control testbed less desirable for developing and comparing various modern control techniques. Therefore, it is the purpose of this paper to describe a more repeatable but more complicated inverted pendulum system as a benchmark system for testing control strategies. The proposed system includes the use of a linear drive motor to eliminate the difficulties associated with the rotary transmission. In addition, a second inverted pendulum is added to create a richer control space and thus be a more effective benchmark for controller evaluation.