A Study Of Range Extension Methods For 3D Micro And Nano Contact Scanning Probes

Contact scanning probes on micro/nano CMMs not only output on/off signals,but also achieves 3D measurements over a range.Several scanning probes based on 2D angle sensors for horizontal displacement and miniature Michelson interferometers for vertical displacement have been developed by the group.However,the extended range in the X/Y direction can lead to a loss of signal in the Z-axis,resulting in a limited range of the probe.Therefore,the expansion of the range of the 3D micro-nano contact scanning probe is investigated in this paper.The following tasks are accomplished in this thesis.Therefore,the extension of the range of the 3D micro-nano contact scanning probe is investigated in this paper.The main tasks include the following.(1)A proposal for the range extension of the probe is presented.The principle and structure of the common optical path scanning probe are introduced,the reasons for the limited range of the scanning probe are analyzed,a fine-tuning structure is proposed to adjust the deflection angle of the reference mirror to extend the range of the probe,and finally the required adjustment angle of the reference mirror is derived from the geometric relationship of the optical path.(2)Modelling and analysis of the designed 2D angle fine-tuning stage.The piezoelectric ceramic controlled 2D angle fine-tuning stage is designed and fabricated according to the analysis of the requirements of the probe range expansion scheme.The range and non-linearity of the piezoelectric ceramic are tested and the coupling of the 2D angle fine-tuning stage is modelled and analyzed.(3)Verification of the auto-following system of the interferometer reference mirror.The 2D angular fine-tuning.structure was assembled into the probe,and the PI table was used to provide a standard displacement for the horizontal direction of the probe,and the output signal of the Z-axis was used as a criterion to judge the range of the probe.The experimental results show that the range of the probe in the horizontal direction can be extended to ± 30 μm.(4)The probes were placed in a thermostat for combined testing and analysis of the sources of error.The results show that the standard deviation of the fixed point of the probe at 30 μm is better than 30 nm,the minimum resolution is better than 5 nm,and the probe drifts by approximately 30 nm over 2 h.