Chapter 1107 I Have Three Methods, Three!

It is of course impossible to say that Chang Haonan can completely understand this technology in just a few dozen minutes.

It's just that he is better at refining the essence of the problem.

With this sentence just now, the subsequent research direction has been basically determined.

That is to say, error modeling is combined with adaptive compensation in the cutting part, while floating clamping is used in the clamping part to minimize the post-processing deformation caused by the fixed area.

Of course, even so, the precision of picking is still not as good as the handwork of a master.

But it’s a necessary step to move the aerospace industry toward true scale.

In fact, Yang Weihua also raised concerns in this regard.

Chang Haonan's answer was the same as in the previous meeting at Haofa Group——

You can carefully select from a batch of products, distinguish several batches with higher consistency, and install them on the same engine respectively.

This seemingly wild idea is almost subversive for Yang Weihua, who has a background in mechanical processing.

He stopped packing his things and stayed there for a long time:

"When I entered the industry, the first thing my master taught me was standardized processing... Now it seems that I am a little behind the times..."

The tone was full of emotion.

Given Yang Weihua's age, he should have entered the industry in the early 1980s, which happened to be the second round of large-scale upgrades in China's machinery industry.

It's been about twenty years now.

You know, in the early years when our country's processing accuracy was not good enough, this method of selecting qualified products from a batch of products was implemented.

It is through the efforts of their generation that a relatively complete standardized processing system has been established.

Now we have to go back.

It belongs to the classic server once it is launched.

"Standardization, of course, is correct."

Chang Haonan also felt the other party's emo, and replied with a smile:

"However, for truly high-demand production, no matter how precise the production method is, there will always be errors, so in terms of processing results, there is no standardization in a strict sense."

"In this case, we might as well change our thinking and implement standardization in the production process field, and use production efficiency to make up for the lack of product consistency to a certain extent..."

In this era, most people’s understanding of “high-level production” is relatively simple.

High precision and good replaceability.

It's still the same thing as in the 1980s.

But in fact, let alone mechanical manufacturing, even in the field of semiconductor processing, there are random errors.

There’s no shame in being special.

The key is to be able to figure it out...

After some enlightenment, Yang Weihua left the conference room thoughtfully.

But Wei Yongming seemed to have no intention of leaving.

Even the laptop on the table was confiscated.

"Yongming, is there anything else?"

Chang Haonan stopped moving when he saw this and sat back on the chair again.

He and Wei Yongming are similar in age, and they are old friends who have known each other for a long time, so they call each other more casually in private.

And Wei Yongming did not talk nonsense and went directly to the topic:

"I just carefully analyzed the clamping method proposed by Lao Yang. If it is refined into a multi-objective optimization problem, there are only three decision variables, but there are more than one objective function...especially for workpieces with a relatively large degree of bending and torsion. Generally speaking, there must be at least four.”

Chang Haonan did not speak, but nodded to indicate that he was right.

This natural look almost made Wei Yongming lose his confidence.

However, after regaining his composure, he continued to speak:

"But... multi-objective optimization using genetic algorithms is generally based on Pareto dominance. As the number of targets increases, the number of non-dominated solutions in the population will increase exponentially, leading to a rapid deterioration of the algorithm's search capabilities..."

"I have previously tested the non-inferior sorting genetic algorithm's solution to a four-dimensional objective optimization problem...even after many rounds of adjustments, it ended up diverging...or a solution with poor accuracy, and the calculation time was exaggerated. For our group It may not matter from a practical perspective, but when it comes to implementation, the production side may not have such high-level computing power support..."

Wei Yongming said as he opened a PDF file on his computer, then turned the screen towards Chang Haonan.

After a brief look at the latter, I found that it was a fairly typical grid search problem.

It seemed like some kind of random test.

"That's true."

Chang Haonan pushed the computer back:

“From an intuitive geometric perspective, an optimization problem with an M-dimensional objective is equivalent to dividing each dimension of the objective space into r grids. Assuming that the non-dominated solutions to the problem are uniformly distributed, then the boundary of the Pareto front of the grid , constitutes the upper bound of the number of particles.”

He said and drew a three-dimensional diagram on the paper.

"Obviously, for an optimization problem with M objectives, M*r^(M-1) solutions are needed to form the Pareto front. For an optimization problem with 5 objectives, even if we set r to a relatively low 25. It still requires nearly a million solutions to describe the basic Pareto front... It is normal for some unexpected calculations to cause divergence, or for several months to be unable to provide results. "

Wei Yongming breathed a sigh of relief.

Obviously, it's not that his question is too simple, it's just that Chang Haonan seems to be mentally prepared:

"Then the next research direction is..."

Unexpectedly, Chang Haonan shook his head directly.

"Not sure yet."

Wei Yongming was immediately shocked.

However, before he could organize his words, Chang Haonan continued:

"I have initially thought of three technical routes, but I don't know which direction is more suitable yet..."

"..."

The former wiped the sweat that had just appeared on his forehead and swallowed back the words that had reached his lips:

"Tell me, if it doesn't work, we can all try..."

This time, Chang Haonan did not write anything more, but took out a notebook that he had prepared long ago:

"First of all... you can enlarge or reduce the objective function value of an individual according to a certain proportion, and then compare it with other individuals, that is, relax the Pareto dominance relationship, so that you can compare the advantages and disadvantages of some non-dominated individuals and enhance the algorithm's performance. Search capabilities.”

Wei Yongming's thinking also moved quickly:

"Using this idea can improve the differential evolution algorithm...but it seems that it can easily lead to individuals falling into cyclic dominance?"

"So it still needs improvement, and the differential evolution algorithm is actually not particularly suitable for this kind of problem... Anyway, we will study it in detail later."

Chang Haonan waved his hand, then turned the notebook to the next page:

"Performance evaluation indicators can also be used as the objective function to replace the Pareto dominance relationship to guide the search process... However, this type of algorithm can only obtain one solution each time it is run, and requires multiple calculations to obtain the optimal solution set, and it is easy to fall into the interval Optimum.”

"The last thing is to not consider the goals that have little impact on the search process or the final optimization results, that is, to reduce the dimensionality of the objective function. I am personally optimistic about the prospects of this technical route, but there are many problems that need to be overcome mathematically..."

Hearing this, Wei Yongming couldn't help but complain in a low voice:

"This is actually a good thing..."

However, Chang Haonan, who has sharp ears, caught it:

"You can't say that."

"After all, we still have to consider the user's feelings... If the algorithm is too complex, we will inevitably encounter obstacles in future promotion..."