PendCon Research: Workshops, Cooperations and Customized Solutions
The Triple Pendulum Experiment
The inverted triple pendulum is the most challenging plant of the PendCon series.
If one attempts to stabilize the triple pendulum with a standard LQ controller, it will be observed that such a controller doesn't work which is in contrast to the double pendulum or the Furuta pendulum. The explanation of this fact is a resonance peak at 460 Hz in the pwm amplifier/motor/encoder part of the hardware. A second obstacle is the Coulomb friction in the bearings. By this way, low frequency and high-frequency dynamics are added to the plant.
If a suitable weighting scheme is chosen with carefully designed weights, the inverted triple pendulum can be stabilized by a Hinf controller. If the mentioned uncertainty is taken into account in the simulation model, it can also be seen that only the Hinf controller is able to stabilize the inverted triple pendulum.
The upper pictures show the stabilzed pendulum in various equilibrium points.
The lower figure shows the configuration for this experiment. Thesignals of the encoder for the third link are wirelessly sent to a receiver. The movements of the pendulum are therefore completely free.
