| 摘要 |
PURPOSE:To judge the occurrence of a jumping phonomenon by generating a jumping signal when the differential value of the three-dimension synthetic displacement signal of a stylus and the comparison voltage in response to the maximum acceleration of the energized stylus are equal. CONSTITUTION:While a stylus 3 is in a profiling operation, it is profile-controlled so that the displacement (z) in the Z direction becomes the preset targer displacement zo, i.e., epsilonz=epsilono. That is, the displacement (z) and the displacement quantity epsilon of the stylus 3 are proportional to a force F energizing it, and the condition for generating a jumping phenomenon is that the acceleration alpha is equal to the maximum acceleration alphamax when the displacement (z) of the stylus 3 is decreased, thereby alpha=alphamax results in alpha<2>epsilon/dt<2>=-K2/K3M.epsilon, where the right side of the equation is determined as the comparison voltage Vc by a comparison voltage generator 9 using constants K2, K3, the mass M of the stylus 3, and the input displacement epsilon from a displacement synthesizer 7, and a comparator 10 outputs a jumping detection signal A when the differential value is equal to the comparison voltage, thus profiling is again performed for that portion at a lower speed. |
