Design of a higher order attachment for the Quanser Qube

In the development of lab exercises for a Dynamic Systems with Controls lab, one constraint on the chosen hardware was that certain types of labs could not be performed. The hardware that was being used, the Quanser Qube, had two existing attachments; with one attachment, an inertial disc, the system was fundamentally a first-order plant. The second attachment, an inverted pendulum, was non-linear and unstable. Neither attachment provided an example of a second-order underdamped plant, nor could a lab be performed with Ziegler-Nichols PID tuning. In order to address these issues, new attachments could be designed and constructed for the Qube, which would add to its range of possible lab exercises. In this paper, one new attachment is described. This attachment features two inertias with compliance and damping. It was designed based on a theoretical model, in order to have certain desired dynamic characteristics, and then model validation was performed. It was found that there were significant unmodeled effects, and an empirical model was derived for the attachment. Due to these effects, the attachment was also limited, and a Ziegler-Nichols lab was still not possible. However, it was possible to perform other lab exercises using this attachment. Based on the empirical model, a sample lab exercise was designed, and an appropriate LabVIEW VI was constructed.