The conception of unconventional escapements is currently a subject of huge interest. The availability of new materials and of new means of production gives rise to improvements of existing escapements or even leads to entirely unpreceded escapement concepts. Acoustic measurement, widely used for rate, beat error and amplitude measurements, is not always suited to measure these new escapements. In this article, first the existing principles for optical measurements are shown: high-speed camera, stroboscopic principle with or without imaging and laser-based systems. Later, the conception and the development of an optical measurement device is presented. The selection of the measurement principles is motivated and the architecture of the optical unit and the units for signal processing is shown. In particular, the system for automatic laser beam alignment is detailed. Finally, some examples of the achieved performances are presented.
Actes du Congrès International de Chronométrie CIC 2016, Montreux (Switzerland)