Design Detecting Systems And Research On Evaluation Methods For Deep-Hole Axis Straightness Error

Parts with deep hole,such as gun-barrel,hydraulic cylinder,pneumatic cylinder,principal axis of bullet train and so forth,are extremely important and indispensable for the mechanical engineering field.Deep-hole axis straightness error is an incredibly important indicator for evaluating whether the quality of a part with deep hole is eligible or not.Besides,the theory and method of evaluating deep-hole axis straightness error can seriously affect the result of the evaluation.In most cases,the detection of the straightness for a deep hole is unavoidable.Deep hole with spiral groove,roundness error and quality error of the surface of the hole,for these reasons,it is hard to find out the axis and the baseline which is used to calculate the straightness of the deep hole;and it is very difficult to calculate the straightness of the deep hole.In order to work out deep-hole's straightness error accurately and rapidly,the author of this paper has been analyzed of the existing research results,and came up with detection theories and testing schemes,and designed testing devices,and wrote corresponding programs to detect and calculate the deep-hole axis straightness error.Firstly,a detection device with ultrasonic thickness gage and a detection device with laser,PSD,three-axis acceleration sensor were designed in this paper.The thoughts of using a method of taking multiple centers as a center of a deep-hole section,least square method and steepest descent method were came up with,and they were applied to the corresponding detection device.Secondly,a method of generating many random points to hunt for the optimal baseline for the evaluation of deep hole axis straightness error and a method of drawing square meshes circularly to hunt for the optimal baseline for the evaluation of deep hole axis straightness error have been come up with in this paper.Through the evaluation of the same set of testing datum,the advantages of the methods which are came up with in this paper have been validated;and the methods improved the accuracy and precision of the evaluating results.Then,the MATLAB programs which correspond to generating many random points to hunt for the optimal baseline for the evaluation of deep hole axis straightness error and drawing square meshes circularly to hunt for the optimal baseline for the evaluation of deep hole axis straightness error were wrote in this paper.In addition,making use of the evaluation algorithm offered in this paper to evaluate the straightnes of a spatial line;and comparing the result with results of other algorithms,to judge whether the algorithm is reasonable or not.The result display that the accuracy of the evaluation of the two methods in the above were improved.Besides,the accuracy of a method of drawing square meshes to hunt for optimal baseline iteratively is better than the other one,but the computation speed and the efficiency of a method of generating random points to hunt for the optimal baseline is better than the former.