Chapter 1167 Producing airplanes like sausages?
"Ahem——"
Just when Yang Liang was ready to perform a live performance of "Facing doubts and apologizing like crazy", a cough suddenly came from the laptop that had been almost ignored by everyone.
The meeting room, which was originally bustling with people coming and going, suddenly became quiet.
However, the warm atmosphere was not interrupted.
As for Yang Liang who was on the stage, when he heard that Chang Haonan seemed to be preparing to ask questions, his limbs became weak, his hands and feet were cold, and he looked like he was about to faint...
The successive attacks from the four people in front of him were already too much for him to deal with.
If this boss strikes another fatal blow...
At a certain moment, two big characters seemed to flash before his eyes.
Delayed.
Although Professor Li Xiongjiang felt a little sorry for his students on the stage, at this point, it was impossible to forcibly interrupt other judges to ask questions.
So I had to force a smile:
"Academician Chang, please ask."
However, Chang Haonan in the picture just tapped the paper on the table with the cap of his pen, and then said something that was beyond everyone's expectations:
"Well...I don't actually want to ask a question."
As he spoke, he pulled two pieces of paper filled with formulas from outside the screen:
"I just want to say that I happen to have some ready-made research results here, which seem to be able to solve the problems raised by several other reviewers just now..."
"???"
The sudden change in the situation at this moment directly confused everyone.
Several professors at the scene were stunned for a moment, and then looked happy——
The reason why they kept asking questions was not because they really didn't want Yang Liang to graduate.
Rather, I am really interested in the subject of the latter's research.
Just asking questions makes the other party hang on the stage and unable to get up...
Now someone has suggested that it can solve the problem. Naturally, curiosity is mixed with excitement.
The same research group, as well as some of the postgraduate students who came here to observe, simply had never seen such a scene before, and were ready to watch the show.
As for Yang Liang, who was about to cry just now...
When this sentence reached his ears, it was like the sound of nature——
During my defense, the academician not only did not ask any questions, but even took the initiative to answer my questions.
If you tell me this, you will be able to brag about it for half your life...
In short, although the conference room is still as quiet as before, the atmosphere has changed 180°...
……
In fact, for Chang Haonan on the other side of the computer, the calibration and compensation of ERS points is not a very complicated problem.
It just requires some theoretical knowledge.
But because of this, it seems difficult to explain this issue clearly in a few words...
After organizing his words for a while, he said:
“As Yang Liang said at the beginning, ERS points are usually deployed on the assembly auxiliary frame to establish the assembly coordinate system. In this case, its displacement and deformation relative to OBP and TBP are linear. , so it is possible to construct an optimization model of the minimum weighted distance error function between multiple sets of compensated ERS theoretical values and actual measured values..."
"For example, for g sets of data measured at m stations and k temperatures, the matching relationship between the measured values and the corrected theoretical values is Σ(i=1,n)(│RnP^k+Tn- Pa^k│)……”
Thanks to the advancement of network technology, Chang Haonan can write this daunting calculation directly on a piece of paper, and then display it close to the screen to everyone on the other side of the network cable.
At the beginning, Yang Liang quickly returned to his seat and took a notebook, ready to write down some useful things.
But before I wrote a few steps, I scratched my head gently, then silently put down the pen, looked forward with eyes full of wisdom, sometimes paused slightly, sometimes frowned in thought...
With this kind of behavior, a truly knowledgeable person can tell at a glance that they want to pretend to understand.
Fortunately, the others either didn't pay attention to the front or were in the same state as him, so nothing happened.
After a slight pause for a few seconds, Chang Haonan put down the paper in his hand and continued to introduce himself:
"This is a typical unconstrained multi-objective nonlinear optimization problem... I wonder if you have read the paper that Professor Abella Lieser and I published last month, which proposed a process. The improved Levenberg–Marquardt algorithm can be used to solve this problem with just a few adjustments. ”
"The only pity is that this achievement is too new, so there is no ready-made preset software available at the moment. If you have program and algorithm design capabilities, you can design your own program for calculations. If not... MathWorks company said some time ago Tian has already contacted Professor Lieser, and MATLAB should soon provide a calculation toolkit..."
"..." Listening to Chang Haonan's explanation, Professor Li Xiongjiang sighed with a hint of regret——
This is called research...
Once an article was submitted, before anything could be done, large companies on the application side came to the door.
But then again, others have a large application-side company in their own hands.
Can't compare, can't compare...
While he was emo-ing, several people who had just enthusiastically asked questions also became motivated again.
Although everyone has not read it yet, or may not even know that Chang Haonan has published a new paper, it is obviously impossible for anyone to question the authenticity of what he just said.
At least it's impossible to question it on the spot.
And if the accuracy problem of large-scale three-dimensional coordinate measurement can be overcome.
Then many problems seem to be solved easily...
"Academician Chang."
The professor who first asked the question once again took the lead:
“Classmate Yang Liang’s research is based on the final assembly of a single machine. So if we zoom in and apply the same technology to the entire production line or even the workshop scale, combined with indoor GPS positioning, is it possible to get rid of the need for special frames in the final assembly process? restrictions?”
The traditional aircraft assembly process adopts a non-automated mode, and each operation is highly dependent on manual labor. Therefore, for aircraft of different models and design features, a series of assembly frames need to be specially designed for the production process.
For example, the frame used to install engines on C808 aircraft cannot be used on C909 aircraft.
Even after some design changes of the same model, the auxiliary tooling must be replaced accordingly.
This undoubtedly greatly reduces production speed and flexibility.
Chang Haonan also responded positively:
“Based on the actual accuracy of current three-dimensional coordinate measuring equipment, it is still very difficult to completely get rid of the formwork... But most of the special tooling can be replaced with general-purpose equipment. On the one hand, the cost can be greatly reduced, and on the other hand, it can also Improve production flexibility and even allow different models to be produced on the same line..."
Speaking of this, he suddenly thought of a classic metaphor from more than half a century ago:
"Produce airplanes like sausages!"
There was a burst of laughter.
Next, several defense reviewers, including Chang Haonan, began intense exchanges and discussions, and for a while they forgot about the main speaker on the podium.
Although Yang Liang felt a little embarrassed, after all, his degree was the most important thing at the moment, so he was happy to see this kind of scene.
However, it is a thesis defense after all.
It is impossible to really treat the respondent as a transparent person.
In the end, it was Chang Haonan who caused the crooked story in the first place and returned to the topic:
"Classmate Yang Liang."
Yang Liang, who was almost in a trance, almost jumped up from the sound. He quickly straightened up his chest and abdomen:
"Academician Chang, please criticize and correct me!"
This somewhat surprised reaction made Chang Haonan laugh a little.
"Don't be nervous. Overall, your defense was very good. It's just that some questions are obviously beyond the scope of this doctoral thesis, but this cannot be regarded as a shortcoming on your part..."
After hearing this comment that had a certain tone, Yang Liang's anxious heart finally calmed down.
Professor Li Xiongjiang saw the right opportunity and resorted to a sudden and sudden drop of the hammer:
"So... judges, do you have any other questions?"
Chang Haonan had already said what he had just said, so it was naturally impossible for others to cause any more trouble. They all shook their heads or waved their hands, indicating that enough was enough.
Zhou Shuwan, who had barely spoken during the entire process, now showed a relieved smile. His tense upper body slowly relaxed and he leaned on the backrest behind him.
Only then did he realize that the back of his shirt was almost soaked——
After all, it’s only been two years since I graduated with my Ph.D., so I can easily recall the memory of my defense...
"Academician Chang is still awesome..."
Looking at the meeting room in front of me that had returned to its happy state, I couldn't help but sigh in my heart:
"Thanks for inviting me here..."
(End of chapter)