Extensive Analysis and Development of Straightness Measurement by Sequential-Two-Points Method

Abstract

Characteristics of errors which might occur in the straightness measurement method due to sequential-two-points were investigated. The investigation made it clear that the slight discrepancies of alignment at the tip between two displacement sensors would be accumulated onto the portion of linear increment generally observed when the straightness is measured; the method of compensation is analytically shown. It is theoretically proposed that the error which might be introduced by the yaw of the tool post and is neglected by the present system can be evaluated by the measurement using sequential-three-points. It is also shown that the measurement system due to the sequential-two-points works stably even for the case when the work on the lathe is rotated. The cylindricity obtained by the measurement during the work rotation agrees well with that obtained by static measurements.

Robot measuring form errors

“…When the scanning step is equal to the distance between sensors (L), the three-probe method is referred to as the S3P method (Sequential Three Points) [5]. Otherwise, when scanning step is smaller than L, the three-probe method is referred to as the G3P method (Generalized Three Points) [6].…”

“…Three-probe methods applied to straightness error measurement are allegedly able to separate part error from both translational and angular errors of the scanning stage [5,6]. However, the three-probe method is extremely sensitive to the presence of zero-adjustment errors of the probes.…”

A three-probe system for measuring the parallelism and straightness of a pair of rails for ultra-precision guideways

“…(7) uses a sequential two-point method to eliminate the stage error, as described in previous studies [6][7][8][9][10][11]. The angular error of the probe stage is required to use Eq.…”

“…This is often referred to as the parallelism of the two rails. There are several methods that are used to obtain a measure of the straightness of each rail [1,2], such as the reversal [3][4][5], sequential two-point [6][7][8][9][10][11], and multi-probe [12][13][14][15][16] methods. These methods generally acquire deviation profiles by eliminating a linear fitted inclined curve; however, they seldom provide information about the relative distance between the pair of rails [17].…”

Development of an automated and dedicated measuring system for straightness evaluation

“…The readings of sensors A, B and C, represented by S A , S B and S C , can be expressed as a function of system errors at position i: Let R Pi be the straightness error of the artefact to be measured, R Ri the probing system translational error motion and δ i and -δ i respective displacement at probes A and C tips due to pitch of the probing device on the scanning direction. When the scanning step is equal to the distance between sensors (L), the three-probe method is referred to as the S3P method (Sequential Three Points) (Tanaka and Sato, 1986). Otherwise, when scanning step is smaller than L, the threeprobe method is referred to as the G3P method (Generalized Three Points) (Gao and Kiyono, 1997).…”