Efficient Active Vibration Control of Smart Structures With Modified Positive Position Feedback Control Using Pattern Search Methods in the Presence of Instrumentation Phase Lead and Lag

For active vibration control applications, positive position feedback (PPF) type controller is quite suitable. These controllers are of low order so are easy to implement in practice. These controllers avoid the problem of control spillover also. However, a systematic design methodology is not available for the design of these controllers. For multimode vibration control applications, in the presence of instrumentation, controller design becomes even more difficult. In the present paper, a systematic design procedure has been suggested to design the PPF controller. The proposed controller is designed by minimizing the H₂ or H_∞ norm of the closed loop (CL) system. The direct search methods based on pattern search technique has been used. The controller designed in this way can provide uniform damping to all the modes. The problems caused by the instrumentation (i.e., phase lead and lag) and time delay actually present in the control loop can be completely eliminated. Since, the controller is designed by minimizing the H_∞ norm of the closed loop system, it is robust in nature. With the proposed methodology, the use of other complicated frequency domain techniques to design the controller can be avoided.