Advanced Sliding Mode Controllers and Their Innovative Applications Using Smart Materials
Singla, Mithun 1983-
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This dissertation focuses on the following two research topics involving smart materials: 1) the advanced sliding mode controllers and their applications and 2) the development of an automatic de-icing system for roads by the electrical heating of embedded carbon fiber. Sliding mode control has widely been used in many different applications. In this dissertation, the active sliding mode control behavior was realized through analyzing the vibration suppression of vortex induced vibrations (VIV) of a jumper pipe structure via pounding tuned mass damper (PTMD) integrated with viscoelastic material. The force generated by the PTMD is analogous to the active sliding mode control. Comparison between simulation and experimental results demonstrated the similarity between the PTMD and the active sliding mode control. Sliding mode controllers are robust to uncertainties and immune to disturbances, but suffer chattering problems due to discontinuities in the control law. In this dissertation, an advanced sliding mode control using the continuous sign function and LQR approach to alleviate chattering is proposed. The desired sliding surface was designed using the stable eigenvectors of the controlled system. Simulation results show that the proposed approach is effective in disturbance rejection and chattering reduction. The robustness of the proposed optimal controller was demonstrated through the implementation of active vibration control on a flexible beam with mass uncertainty. The experimental results show that the vibrations of the beam with mass uncertainty can be well controlled by the proposed approach. Due to the inability to guarantee stability of a system with unmatched uncertainties, the proposed approach is improved by replacing the LQR approach with the H∞ approach. The stability of the proposed approach was verified with the H∞ approach. The simulation results show that the control input generated by the proposed robust approach was very smooth compared to conventional sliding mode controllers. The experimental implementation for vibration control of a base-isolated structure equipped with an MR damper, where the nonlinear force generated by the MR damper acted as an uncertainty to the system, showing the effectiveness of the approach. Lastly, an innovative de-icing system using carbon fiber as the heating element was developed. A test sidewalk was prepared by embedding electrically powered carbon fiber frames into the concrete pavement. A LabVIEW interface controlled the de-icing process through two sidewalk surface temperature controllers (ON-OFF and Fuzzy Logic) and enabled the user to keep track of the environmental conditions. The experimental results showed that the proposed technique effectively prevented the formation of ice on the pavement surface and that the advanced temperature controller was 80% more power efficient compared to a manual on-off switch.