VIBRATION REDUCTION

摘要

A cross axis actuator (1.1) for reducing the transmission of vibration along elongate members (1.2) comprising a series of windings (1.5, 1.6, 1.7, 1.8, 1.9, 1.10) wound helically at 30° pitch around the member (1.2) along part of its length in clockwise and anti-clockwise fashion and are anchored at two or more points (1.3, 1.4) to the member (1.2), the windings (1.5, 1.6, 1.7, 1.8, 1.9, 1.10) being able to be subjected to strain which causes deformation of the member (1.2) between attachment points (1.3, 1.4). The member (1.2) can be either a steel pipe or a rod. The windings (1.5, 1.6, 1.7, 1.8, 1.9, 1.10) can either be in the form of steel wires or be strips of material. The numbers of windings (1.5, 1.6, 1.7, 1.8, 1.9, 1.10) wound around the member (1.2) in a clockwise and anti-clockwise direction should be equal. Ideally, the windings (1.5, 1.6, 1.7, 1.8, 1.9, 1.10) are attached to the member (2) on a continuous basis except for the ends which are left free. The strain is generated from actuators, preferably made from piezo electric materials, which can either be attached to the ends of the windings (1.5, 1.6, 1.7, 1.8, 1.9, 1.10) or form part of the windings (1.5, 1.6, 1.7, 1.8, 1.9, 1.10). The actuators can be controlled by control signals which are calculated by a control unit based on signals produced by vibration sensors (1.13, 1.14). Ideally, part of the member (1.2) is formed to produce an impedance mismatch with the rest of the member (1.2). This can be achieved by having a flexible section (1.2a) within the member (1.2). The windings (1.5, 1.6, 1.7, 1.8, 1.9, 1.10) are usually attached across this section (1.2a).