(Georgia Institute of Technology, 2018-04-30)
Manghaipathy, Pavithra
To prevent failure due to fatigue, especially in high-performance aircraft, there is a significant amount of interest in vibration suppression methods with a special focus on active vibration control methods. This thesis demonstrates vibration controller designs, by using a combination of acceleration & positive position feedback (PPF), acceleration & velocity feedback and positive position feedback (PPF) & velocity feedback, along with smart actuators based on piezoelectric stacks in order to address the issue. While several feedback and controller methods exist, this previously unexplored design was chosen to emphasize the effects of two types of combined feedback over a single feedback. Noting the work by Caughey & Goh (1983) and Fanson (1984) for the controller design process, this thesis aims to perform a stability analysis and expand on the use of the method designed by Hanagud & de Noyer (1998); a control method which uses a single specified closed frequency and a preset closed loop damping ratio to control the damping. Therefore, the new research presented in this thesis includes the following: 1. Study combinations of two feedbacks (Acceleration & Velocity, Position & Velocity and Acceleration & Position) to design controllers that yield a single closed loop frequency for specified closed loop damping ratio and a new solution technique of equating coefficients of the transfer function denominator. 2. Modifying the design to include frequencies other than the single closed loop frequency by adding perturbations about a single closed loop frequency ωf. 3. Search for a design that uses minimum energy required by the controller to suppress and control vibrations. 4. Search for the best combination; Acceleration & Velocity, Position & Velocity or Acceleration & Position Feedback design.