Binocular-vision-based error detection system and identification method for PIGEs of rotary axis in five-axis machine tool

2018 ◽  
Vol 51 ◽  
pp. 208-222 ◽  
Author(s):  
Wei Liu ◽  
Xiao Li ◽  
Zhenyuan Jia ◽  
Hui Li ◽  
Xin Ma ◽  
...  
2015 ◽  
Vol 9 (4) ◽  
pp. 387-395 ◽  
Author(s):  
Soichi Ibaraki ◽  
◽  
Yu Nagai ◽  
Hisashi Otsubo ◽  
Yasutaka Sakai ◽  
...  

The R-test measures the three-dimensional displacement of a precision sphere, attached to a machine spindle, by using three displacement sensors fixed to the machine’s table. Its application to error calibration for five-axis machine tools has long been studied. This paper presents software for analyzing the measured R-test trajectories for error diagnosis and numerical compensation for rotary axis location errors and error motions. The developed software first graphically presents the measured R-test trajectories to help a user intuitively understand error motions of the rotary axes. It also numerically parameterizes the rotary axis geometric error parameters, and then generates a compensation table that can be implemented in some latest-generation commercial CNC systems. An actual demonstration of its application to a five-axis machine tool with a universal head (two rotary axes on the spindle side) is presented.


2012 ◽  
Vol 6 (2) ◽  
pp. 180-187 ◽  
Author(s):  
Yukitoshi Ihara ◽  

A ball bar is a very convenient device for measuring the motion accuracy of machine tools. Some trials have also been done for measuring motion accuracy of industrial robots. Nowadays, multi-axis machines such as five-axis machining centers are very popular, and therefore, there is increased demand for checking their accuracy. This paper introduces an idea for checking the motion accuracy of five-axis machining centers and diagnosing error sources by reviewing trial measurements on articulated industrial robots. There are two problems. The first problem is that the ball bar can measure only distances, and the second problem is that the ball bar is a linear device and therefore not suitable for the rotary axis motion of 5-axis machines and articulated robots. Finally, the test conditions for the measurement of the motion accuracy of a machine tool showing conical motion, by using the ball bar and ISO/DIS 10791-6 (which is currently being edited) are reviewed and verified.


Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1686 ◽  
Author(s):  
Nancy Agarwal ◽  
Mudasir Ahmad Wani ◽  
Patrick Bours

This work focuses on designing a grammar detection system that understands both structural and contextual information of sentences for validating whether the English sentences are grammatically correct. Most existing systems model a grammar detector by translating the sentences into sequences of either words appearing in the sentences or syntactic tags holding the grammar knowledge of the sentences. In this paper, we show that both these sequencing approaches have limitations. The former model is over specific, whereas the latter model is over generalized, which in turn affects the performance of the grammar classifier. Therefore, the paper proposes a new sequencing approach that contains both information, linguistic as well as syntactic, of a sentence. We call this sequence a Lex-Pos sequence. The main objective of the paper is to demonstrate that the proposed Lex-Pos sequence has the potential to imbibe the specific nature of the linguistic words (i.e., lexicals) and generic structural characteristics of a sentence via Part-Of-Speech (POS) tags, and so, can lead to a significant improvement in detecting grammar errors. Furthermore, the paper proposes a new vector representation technique, Word Embedding One-Hot Encoding (WEOE) to transform this Lex-Pos into mathematical values. The paper also introduces a new error induction technique to artificially generate the POS tag specific incorrect sentences for training. The classifier is trained using two corpora of incorrect sentences, one with general errors and another with POS tag specific errors. Long Short-Term Memory (LSTM) neural network architecture has been employed to build the grammar classifier. The study conducts nine experiments to validate the strength of the Lex-Pos sequences. The Lex-Pos -based models are observed as superior in two ways: (1) they give more accurate predictions; and (2) they are more stable as lesser accuracy drops have been recorded from training to testing. To further prove the potential of the proposed Lex-Pos -based model, we compare it with some well known existing studies.


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