Enhanced Damping of Flexible Structures Using Force Feedback

Abstract

International audienceDuring the last three decades, several active damping strategies have been proposed, based on the so-called passivity concept, or equivalently, on the power port concept. One of them, known as Integral Force Feedback (IFF) is reviewed in this paper. Actually, the main drawback of the IFF is that high active damping is obtained at the cost of a degradation of the compliance at low frequency, compromising the capability of disturbance rejection. Classically, a trade-off between damping and stiffness can be reached by adequately high pass filtering the control signal. However, the high pass filter poles and zeros often interfere with the plant dynamics, which in turn compromises the guaranteed stability of the IFF. In this paper, a novel type of high pass filter is proposed. It is shown that this modification makes the controller unconditionally stable, and increases drastically the achievable modal damping. Analytic formulas are derived, and illustrated using simple numerical models. The characteristics of the proposed controller are discussed in terms of maximum modal damping and transmissibility

Active tuned inerter-damper for smart structures and its ℋ∞ optimisation

“…the control parameters g dn is set to 0 and g sn is tuned according to Eq. (18). It is seen that the global minimal maximum is located at zero frequency instead of that at the fixed point given in Eq.…”

“…The optimal g sn can be taken in practice by calculating the quadratic average of Eqs. (18) and (19), which is given by:…”

“…Chesné et.al. [18] proposed to include a high pass filter to the controller to compensate for the loss of the static stiffness. By doing so, it also facilitates the practical implementation of the ATID as over-amplifications of low frequency signals due to the use of the integrators could be avoided.…”

“…By doing so, it also facilitates the practical implementation of the ATID as over-amplifications of low frequency signals due to the use of the integrators could be avoided. However, its unconditional stability property is compromised as illustrated in [18].…”

“…By feeding back the output of the force sensor through a resonant controller to derive the actuator, the proposed device behaves equivalently to a parallel connected inerter-damper-spring system. Another type of resonant controller, termed a controller, was investigated [17,18] for closing the loop between the force actuator and the force sensor, aiming to further improve the performance of the traditional active damping strategies, however the physics behind this controller was not yet fully interpreted. For both types of controllers, the corresponding controller parameters were optimised using the maximum damping criterion.…”