Evaluation of Input-Shaping Control Robustness for the Reduction of Torsional Vibrations

Aircraft drivetrains connect the engine to the electrical power system. In most cases, the drivetrains are relatively flexible and have vibration modes with values below 100 Hz to reduce weight and size. Therefore, electrical loads’ connection and disconnection may excite torsional vibrations in the machine's shaft, reducing the drivetrains’ lifespan. This interaction is known as electromechanical interaction. This issue can be mitigated using an input-shaping strategy, which reduces the excitation of torsional vibrations by connecting the electrical loads following a pattern, dependent on the drivetrain's natural frequencies. However, since this method is based on the knowledge of the vibration modes attributes, it can be susceptible to parameter's uncertainty. In this article, a pulsating input shaping method's robustness is assessed, analyzing simulation and experimental results. The effect of the inductances is analyzed, and a strategy to reduce its effect is proposed. Furthermore, the effect of uncertainty in the mechanical parameters is evaluated, and theoretical analysis is carried out to establish safe operating limits. The theoretical analysis is experimentally validated.