Characteristics of Active Forces in Structural Hybrid Mass Damper Control Systems

This paper gives the numerical analysis on characteristics of active force in HMD control systems. In order to quantitatively evaluates the direction characteristics of active force with respect to the relative displacement or velocity of mass piece, a set of five performance indexes are defined, and also the ratios of either peak value or RMS value of active force to inertia force. This set of indexes can be viewed as a measurement to quantitatively study the intrinsic behavior of active force and also a kind of reference to evaluate the feasibility of employing semi-active variable damping or semi-active variable stiffness devices to replace active actuators in HMD systems. Secondly, under the model of a SDOF structure system controlled by one HMD system, the influence of soft parameters of LQR control algorithm are analyzed according to four sets of Q value and a large range of r values. Both quantitative results and qualitative results show that confinement on mass velocity is the key point whether can achieve good control performance or not. Thirdly, under the background of the 76-floor benchmark problem, the active hysteretic loop of active force versus velocity is given, which again shows that the direction characteristic of active force in HMD system. In the end, some conclusions are achieved and the feasibility of utilizing semi-active variable damping or semi-active variable stiffness devices in replacing active actuators in HMD control system is also evaluated. _____________ Chunwei ZHANG, School of Civil Engineering, Harbin Institute of Technology, P.O.Box 2546, 202 Haihe Road, Nan’gang District, Harbin 150090, CHINA Jinping OU, School of Civil Engineering, Harbin Institute of Technology, 92 West Dazhi Street , Nan’gang District, Harbin 150001, CHINA INTRODUCTION The essence of active mass damper/driver (HMD) system used in civil engineering vibration control can be attributed to tuned mass damper (TMD) absorber system plused by an active actuator device. Sometimes such kind of system is also called hybrid mass damper (HMD) and the conceptional constitution of which is shown in figure 1(a). As compared with figure 1(b), AMD is the simplest form of HMD, which is only made up of mass piece and actuator device while the damper and spring element are absent from the system. In the following of this paper, we name the system with structure shown in figure 1 (a) and (b) as HMD system.