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Unformatted text preview: he following three terns of values:
p 1 (x 1 , y1 , z1 ) ; p 2 (x 2 , y 2 , z 2 ) ; p 3 (x 3 , y 3 , z 3 ) (1) The proposed approach considers the uncertainty source in the positioning error of the drilled holes pattern due to the variance in the positioning of the locators. It aims to minimise the machining uncertainty due to this source. It neglects the tool positioning error or the geometric deviations on datum elements. The six coordinates of the locators (1) in the machine reference frame XOY are considered distributed according to a gaussian probability density function with mean equal to the nominal position of locators and standard deviation σ : ( ) x 2 ≈ N (x 2n , σ 2 ) x 3 ≈ N (x 3n , σ 2 )
x 1 ≈ N x 1n = 0, σ 2 ( ) y 2 ≈ N (y 2n = 0, σ 2 ) y 3 ≈ N (y 3n = 0, σ 2 )
y1 ≈ N y1n , σ 2 (2) with x i n , y i n nominal values of the locator coordinates in the machine reference frame (MRF). The perturbed part reference frame (PRF) X’O’Y’ is related to the actual position of the locators. In particular, the X’ axis is the straight line passing through the...
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This note was uploaded on 08/03/2010 for the course DD 1234 taught by Professor Zczxc during the Spring '10 term at Magnolia Bible.
- Spring '10
- The Land