Chapter 1167 Producing Airplanes Like Producing Sausages?

“Ahem——”

Just when Yang Liang was ready to perform a “crazy apology in the face of doubts” on the spot, a cough suddenly came from the laptop that was almost ignored by everyone.

The originally lively meeting room 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 and his hands and feet were cold, and he looked like he was about to faint...

The successive attacks of the four people in front of him had already exhausted him.

If this big guy came with a fatal blow again...

At a certain moment, two big words seemed to flash before his eyes.

Delayed graduation.

Although Professor Li Xiongjiang felt a little sorry for his own students on the stage, it was impossible to forcibly interrupt other judges to ask questions at this point.

So he had to force a smile:

"Academician Chang, please ask."

However, Chang Haonan in the picture just tapped the paper on the table with the pen cap, and then said something that was beyond everyone's expectations:

"Well... I don't actually want to ask questions."

He then pulled in two papers full of formulas from outside the screen:

"I want to say that I just have some ready-made research results here, which seem to be able to solve the questions raised by the other reviewers just now..."

"???"

This sudden change in the situation at this moment directly confused everyone.

The professors at the scene were stunned at first, and then showed joy on their faces-

The reason why they asked a series of questions was not that they really didn't want Yang Liang to graduate.

But they were really interested in the topic that the latter was studying.

It's just that as they asked, the other party was hung up on the stage...

Now that someone said that they could solve the problem, they were naturally curious and excited.

And the same research group, as well as some graduate students who came to listen to the lecture, simply had never seen such a scene before, and were ready to start watching the show.

As for Yang Liang who was about to cry just now...

This sentence sounded like heavenly music to his ears-

When I defended my thesis, the academician not only did not ask any questions, but even took the initiative to help me answer the questions.

I can brag about this for half my life...

In short, although the conference room was still as quiet as before, the atmosphere had changed 180 degrees...

...

In fact, for Chang Haonan on the other side of the computer, the calibration and compensation of ERS points was not a very complicated problem.

It just required some theoretical knowledge.

But it is also because of this that it seems difficult to explain this problem in a few words...

After organizing his words for a while, he began to speak:

"As Yang Liang said at the beginning, ERS points are usually deployed on the assembly auxiliary jig to establish the assembly coordinate system. In this case, the displacement and deformation relative to OBP and TBP are linear, so the optimization model of the minimum weighted distance error function between multiple sets of compensated ERS theoretical values ​​and actual measured values ​​can be constructed..."

"For example, the matching relationship between the measured value and the corrected theoretical value of g sets of data measured at m stations and k temperatures is Σ(i=1,n)(│RnP^k+Tn-Pa^k│)..."

Thanks to the advancement of network technology, Chang Haonan can write this difficult-to-read formula directly on a piece of paper, and then show it to the people on the other side of the network cable close to the screen.

At first, Yang Liang quickly returned to his seat and took a notebook to write down some useful things.

But before writing a few steps, he scratched his head lightly, then silently put down the pen, looked forward with eyes full of wisdom, and sometimes nodded slightly, and sometimes frowned as if thinking...

This kind of behavior, people who really know the business can see at a glance that he is trying to pretend to understand.

Fortunately, the others either didn't pay attention to the front at this time, or were in the same state as him, so nothing happened.

After a short pause of 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 don't know if you have read the paper that Professor Abela Liesel and I published last month. It proposed an improved Levenberg-Marquardt algorithm. With a little adjustment, it can be used to solve this problem."

"The only pity is that this result is too new, so there is no ready-made preset software available. If you have the ability to design programs and algorithms, you can design your own program to calculate. If not... MathWorks has contacted Professor Liesel a few days ago, and MATLAB should soon provide a calculation toolkit..."

"..."

Listening to Chang Haonan's explanation, Professor Li Xiongjiang sighed with a sigh--

This is what people call research...

An article was submitted, and before anything happened, a large application-side company took the initiative to come to the door.

But then again, others have a large application-side company in their hands.

There is no comparison...

While he was being emo, the people who had asked questions enthusiastically just now were also re-motivated.

Although no one has actually read it yet, or even knows that Chang Haonan has published a new paper, it is obviously impossible for anyone to question the truth of his statement just now.

At least it is 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...

"Academician Chang."

The professor who asked the question at the beginning took the lead again:

"Student Yang Liang's research is based on single-machine assembly. If we expand our perspective and apply the same technology to the entire production line and even the workshop scale, combined with indoor GPS positioning, is it possible to get rid of the restrictions of the assembly process on special jigs?"

The traditional aircraft assembly process adopts a non-automated mode, and various operations are highly dependent on manual labor. Therefore, for aircraft of different models and design features, a series of assembly jigs need to be specially designed for the production process.

For example, the jig for installing the engine for the C808 aircraft cannot be used for the C909 aircraft.

Even after some design changes, the same model needs to be replaced with auxiliary tooling accordingly.

This undoubtedly greatly reduces production speed and flexibility.

Chang Haonan also gave a positive response:

"With the actual accuracy of the current three-coordinate measuring equipment, it is still difficult to completely get rid of the jig... But most of the special tooling can be replaced with general equipment, which can greatly reduce costs on the one hand, and improve production flexibility on the other hand, and even allow different models to be produced on the same line..."

At this point, he suddenly thought of a classic metaphor from more than half a century ago:

"It's like producing airplanes like sausages!"

This immediately caused a burst of laughter.

Next, several defense judges including Chang Haonan began to communicate and discuss intensively, and for a while they forgot the main subject on the podium.

Although Yang Liang felt a little embarrassed, his degree was important at the moment, so he was happy to see this scene.

However, it was a thesis defense after all.

It is impossible to really treat the respondent as a small transparent person.

Finally, it was Chang Haonan, who had first caused the discussion to go off topic, who returned to the main topic:

"Student Yang Liang."

Yang Liang, who was almost in a trance, was almost frightened by this voice and quickly stood up straight with his chest and abdomen straightened:

"Academician Chang, please criticize and correct me!"

This somewhat startled reaction made Chang Haonan laugh.

"Don't be nervous. Overall, your defense was very good, but some questions obviously exceeded the research scope of this doctoral thesis, but this cannot be regarded as your shortcomings..."

Hearing this evaluation with a bit of a tone, Yang Liang's heart finally calmed down.

Professor Li Xiongjiang seized the opportunity and used a confused and sudden hammer trick:

"So... Dear reviewers, 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 it was enough.

Zhou Shuwan, who had not spoken much during the whole process, also showed a relieved smile, and his tense upper body slowly relaxed, leaning on the backrest behind him.

It was not until this moment that he realized that the back of his shirt was almost soaked -

After all, it was only two years after graduating from his doctorate, and it was easy to recall the memory of his defense that year...

"Academician Chang is still awesome..."

Looking at the conference room in front of him that had returned to a happy state, he couldn't help but sigh in his heart:

"Thanks for inviting me here..."