| 摘要 |
<p>A method of measuring the position of a workpiece surface is disclosed which utilises an analogue probe which produces at least one output indicative of the amount of stylus deflection. The probe is driven by a machine towards the surface, and when contact is made the initial deflection signal triggers the machine controller to read simultaneously the outputs of the machine scales and the probe output at the time of the signal and at several further instants over a short time period before the machine is stopped. A computer then plots the relationship between the probe readings and the machine scale readings and extrapolates it back to the point at which the probe stylus deflection was zero. This gives an indication of the position of the stylus at the actual instant of contact. A further benefit is that, because the probe stylus remains in contact with the workpiece surface for a short time while readings are being taken, any inaccuracies introduced because of machine vibration can be averaged and thus reduced by plotting a best fit line through the recorded points.</p> |
