Vibration Modeling and Control of Drilling Tools Using Micro Fiber Composite Actuators

For parametric design and performance evaluation of active tool wave cancellation methods in Logging While Drilling (LWD) operations, the vibrational behavior of a cantilever beam representing the LWD tool structure has been modeled. Vibration sensing and control are achieved by a series of Macro Fiber Composite (MFC) transducers mounted on the beam surface, along the wave propagation path. Analytical studies and numerical simulations have been performed to investigate the wave propagation characteristics and quantify the transducer performance. Using strain at discrete locations along the beam as the feedback signal, a series of cascaded single-input and single-output (SISO) control systems has been realized. From comparative analysis of the wave structure and energy obtained with and without the active control scheme, it is observed that significant reduction in the strain amplitude and energy dissipation can be achieved under the active control mode. The result demonstrates that the active control method, in collaboration with the embedded smart material sensing and actuating scheme, is effective and practical for tool wave cancellation.