A device laboratory was designed to create a commanded disturbance to the Furuta inverted pendulum. This pendulum was modified by adding a second inverted pendulum coupled to the main one by means of a semi-rigid spring. The induced motion on the second inverted pendulum causes displacement of the center of mass of the system, producing a kind of perturbation similar to that presented on mobile inverted pendulum transportation units. A linear matrix inequality (LMI) controller is designed from the unperturbed model (based on the main pendulum without the second inverted one) and implemented to our system. Then, experimentally, the behaviour of the whole closed-loop system and the controller performance was analysed. According to the laboratory test, the LMI controller is robust enough in front of perturbation induced on the second pendulum.