| 摘要 |
<p>An optical system for monitoring torsional vibration of a shaft (112) has an optical unit (104) including IRLED radiation sources (208) aimed at grid lines (114) applied around the circumference of the shaft (112). The reflection of the radiation is imaged through lenses (204) and a matching Ronchi grid (218) onto a photodiode (220) which produces a periodic wave signal from which indications of rotational irregularities can be derived. In one embodiment, duplicate optical units (104) are arranged in diametric opposition across the shaft (112) to compensate for pitch and plunge vibration. In another embodiment, a second duplicate optical unit (104) is located at a distance along the shaft from the first unit (104). The output signals of the two units (104) are passed through a comparator (406), an EX-NOR gate (430) and a low-pass filter (432) to produce a signal indicative of torsional deflection. Also disclosed are a method and apparatus for precisely applying finely spaced grid lines (114) to an existing shaft (112) on site.</p> |
