Active Vibration Control on a Smart Composite Structure using Modal-Shaped Sliding Mode Control

This paper proposes an active modal vibration control method based on a modal sliding mode controller applied to a smart material composite structure with integrated piezoelectric transducers as actuators and sensors. First, the electromechanical coupled system is identified using a modal reduced-order model. The sliding surface is based on the modal-filtered states and designed using a general formulation allowing the control of multiple vibration modes with multiple piezoelectric sensors and actuators. The performance and stability of the nonlinear controller are addressed and confirmed with the experimental results on a composite smart spoiler-shaped structure. The nonlinear switching control signal, based on the modal-shaped sliding surface improves the performances of the linear part of the control while maintaining not only stability but also robustness. The attenuation level achieved on the target modes on all piezoelectric sensors starts from -14dB up to -22dB, illustrating the strong potential of nonlinear switching control methods in active vibration control.

Foundation forces caused by dynamic air gap torques of converter driven induction motors influenced by active vibration control: a theoretical analysis

In the paper, a theoretical analysis regarding foundation forces caused by dynamic air gap torques of converter-driven induction motors, influenced by active vibration control, is shown. Based on a plane model, where actuators are placed between the motor feet and steel frame foundation and where the vertical motor feet accelerations are controlled, a mathematical description in the time domain, Laplace domain, and Fourier domain is presented, as well as a block diagram for numerical simulation. A numerical example is shown, where a 2-pole induction motor (2 MW) is analyzed for different cases—motor directly mounted on a steel frame foundation (case 1), actuators between motor feet and foundation, operating passively (case 2) and actively (case 3). It could be shown, that with the presented active vibration control concept the foundation forces due to dynamic air gap torques can be clearly reduced.

Modelling of Flexible Manipulator System via Ant Colony Optimization for Endpoint Acceleration

The application of flexible manipulators has increased in recent years especially in the fourth industrial revolution. It plays a significant role in a diverse range of fields, such as construction automation, environmental applications, space engineering and many more. Due to the lightweight, lower inertia and high flexibility of flexible manipulators, undesired vibration may occur and affect the precision of operation. Therefore, development of an accurate model of the flexible manipulator was presented prior to establishing active vibration control to suppress the vibration and increase efficiency of the system. In this study, flexible manipulator system was modelled using the input and output experimental data of the endpoint acceleration. The model was developed by utilizing intelligence algorithm via ant colony optimization (ACO), commonly known as a population-based trail-following behaviour of real ants based on autoregressive with exogenous (ARX) model structure. The performance of the algorithm was validated based on three robustness methods known as lowest mean square error (MSE), correlation test within 95% confidence level and pole zero stability. The simulation results indicated that ACO accomplished superior performance by achieving lowest MSE of 2.5171×10−7 for endpoint acceleration. In addition, ACO portrayed correlation tests within 95% confidence level and great pole-zero stability.

Effectiveness of line type and cross type piezoelectric patches on active vibration control of a flexible rectangular plate

In the present work, vibration control of a simply supported plate with line type and cross type piezoelectric (PZT) patches are investigated with and without actuation voltage. The plate is modeled under the assumption of Kirchhoff’s Plate theory. The mass of PZT patches remain constant in all cases. In case of actuation, applied voltage considered are 1, 2 and 3 mV. The external excitation to the plate is in the form of harmonically varying point load of 1 mN. It is noticed that cross type PZT patch is more effective in deflection suppression of plate than that of line type PZT patch at 3 mV of actuation at patch thickness of 0.75 μm. Suppression of central deflection of plate for line type and cross type PZT patches are obtained in different frequency bands of (175–185 Hz) and (870–880 Hz) respectively.