| 摘要 |
PURPOSE:To reduce the vibration much with a small controlling force, by detecting the vibration quantity generated in a structure body such as a traffic route bridge and giving a controlling force proportional to the vibration quantity to a position where the amplitude of a natural mode governing the vibrating behavior of the structure body is maximum. CONSTITUTION:The physical quantity of the vibration (displacement, speed, and acceleration) of a vibrating system 3 of the traffic route bridge as an object whose vibration should be reduced is measured by a vibration detector 4, and a controlling force corresponding to the vibration is generated from a driving device 6 through a controlling circuit 5 and is applied to the controlling system 3 to reduce the vibration. If there are plural natural modes to be controlled, the control is performed for each natural mode. When a bridge 1 is regarded as a beam having a uniform sectional stiffness and piers 2 are regarded as simple supporting points, the bridge 1 receives an external force and vibrates in infinite natural modes, but a primary natural mode (a), a secondary natural mode (b), and a tertiary natural mode (c) are taken as control objects, and loops are in positions L/2, L/4, and L/6 for modes (a)-(c) respectively when the span of the bridge 1 is denoted as L. A controlling force P is given to said positions of loops to control the vibration efficiently. |
