Papers by Author: Yoshikazu Arai

Abstract: This paper describes an atomic force microscope (AFM) based instrument for 3D edge profile measurement of single-point diamond cutting tools. The instrument is composed of an AFM unit and an optical sensor for alignment of the AFM probe tip (silicon cantilever) with the diamond cutting tool edge. In the optical sensor, a laser beam from a laser diode along the Y-axis is focused to generate a small beam spot with a micrometer-order diameter at the beam waist, and then received by a photo-detector (photodiode). The tool edge top and the AFM probe tip are brought to the center of the beam waist in the XZ-plane through monitoring the variation of the photodiode output, respectively. Consequently, the AFM tip can be aligned with the tool edge top. Alignment experiments and 3D edge profile measurements of a round-nose type single-point diamond tool are carried out.

Abstract: In this paper, we applied the contact constant-height mode together with the pre-compensation technique which can realize the capability of high speed as well as faithful topographical image. Before scanning, the slope variation of the micro-structured surface was measured by the capacitance sensor and then stored in a PC. During the surface profile scanning, a piezoelectric actuator is applied which can provide the inconsecutive motion that corresponds to the pre-measured slope variation. As a result, the precision measurement can also be achieved. The validity of the proposed method and its performance are verified by compare the topographical images that were gained by the contact constant-force mode with feedback control. However, the scanning speed of our method is obviously high.

Abstract: In this study, a novel control law including a fine-tuned PID component to yield basic dynamic performance, and a component derived from the Sliding Mode Observer (SMO) to estimate and then compensate for modeling uncertainties and disturbances, has been introduced to planar actuator of an ultra-precision positioning stage. Experimental results are presented to verify the effectiveness of suggested dynamic compensation strategy and tracking performance of the non-contact planar actuator.

Abstract: A novel scanning probe measurement system has been developed to achieve precise profile measurements of micro-aspheric surfaces. The system consists of a scanning stage (a spindle and a linear slide) and a sensor unit. The sensor unit consists of a ring artifact, two capacitance sensors and a contact-mode displacement sensor. The two capacitance sensors scan the surface of the ring artifact to measure and compensate the error motions of the scanning stage while the contact-mode displacement sensor scans the surface of a micro-aspheric. In this paper, a new contact-mode displacement sensor that has a small contact force of less than 2.3 mN and a stable output has been developed. After investigating the fundamental performance of the contact-mode displacement sensor, the sensor has been applied to the micro-aspheric surface profile measurement system. The effectiveness of the measurement system has been verified by the measurement results.

Abstract: This paper describes a multi-probe method for measuring the straightness error of a leadscrew-driven stage. Two displacement probes are employed to scan a flat artifact mounted on the stage. The surface profile error of the flat artifact is separated from the straightness error of the stage in a differential output of the probes. The straightness error can thus be obtained accurately from an integration operation of the differential output without the influence of the surface profile error. An improved technique of data processing is adopted for measurement of straightness error components with periodicity shorter than the probe spacing. The influence of the angular error of the stage is compensated for by using the result measured by an autocollimator. Experiments of straightness measurement of a leadscrew-driven stage with a lead of 1 mm were carried out by using two flat artifacts with different degrees of precision. The successful detection of the short-periodicity component of the straightness error with a periodicity equal to the lead indicated the feasibility of the multi-probe method.