Chapter 60 The Opening of the National Competition!

On September 12, the competition is going on as scheduled!

The day before the competition, Lu Zhou and others took the school bus from the new campus back to the old campus, and lived in the temporary dormitory arranged by the school.

Mattresses and pillows are prepared, so you only need to bring a set. People who are not particular can even go directly to the individual. After all, although the game time is 72 hours, the average bedtime for each person may be ten consecutive hours. less than an hour.

For example, Lu Zhou is like this.

He had the heaviest task and the largest amount of work to be done. He could only take a nap the next day, so he didn't even bring a change of clothes and left empty-handed. The first thing I did when I arrived at the new dormitory was to lie down and go to bed.

If you can't sleep, you have to force yourself to fall asleep.

I woke up at five o'clock the next morning, and sat on the bed with my eyes closed until seven o'clock. I went to the cafeteria to have breakfast. Lu Zhou, Wang Xiaodong and Lin Yuxiang met and went to school to prepare for the Mathematical Modeling Contest. Dedicated computer room.

According to the official registration information, this competition has more than 70,000 college students from 25,347 teams from 33 provinces, municipalities, autonomous regions (including Hong Kong and Macao) and 1,338 universities in the United States and Singapore. At the same time, click the competition website to download the questions to participate Contest.

The competition is co-sponsored by the Department of Higher Education of the Ministry of Education and the Huaguo Society of Industrial and Applied Mathematics. Although its influence is slightly less than that of the "Challenge Cup" due to the rigor and fairness of the evaluation, the gold content of the National Award is in some senses. Better than the "Challenge Cup".

At 7:30 in the morning, the computer room was already full of ten teams.

Although many people choose to use their own laptops to answer questions, they usually bring their computers to the computer room. After all, only the wifi in the computer room and the library can download papers from Zhiwang for free. This kind of competition is expected to win through the unverified information on Baidu, it is better to burn a stick of incense and other papers automatically.

Mr. Liu came over and walked around, smiled and greeted Lu Zhou and the three. He didn't talk about the competition, he just said "How was your rest last night?", "Are you used to the dormitory in the old campus? ?" and so on, then wandered outside the computer room and drove back to the new campus to work on his own projects.

At eight o'clock, the bell rang.

Everyone quickly landed on the official website and downloaded the title.

According to the rules, the questions are divided into four major questions, ABCD, among which AB belongs to the undergraduate group and CD belongs to the specialist group. Each group chooses a question as the goal, completes and uploads the md5 code generated by the official website software within 72 hours, and uploads the pdf format paper corresponding to the md5 code on the day of the end of the competition.

Generally speaking, the topic selection must be controlled within half an hour, and everyone is racing against time to read the topic.

However, when they saw the title, everyone was dumbfounded.

"Question A, Chang'e-3 soft landing orbit design and control strategy... Question B, creative flat-panel folding table?! Holding grass? What the hell is this year's topic?"

"MMP, it's totally different from the training we do!"

"I seem to have done something similar a few days ago. It seems to be designing the launch plan of the Shenzhou rocket... But I think such a mysterious theme will definitely not come out. I didn't expect... to be careless!"

"Hold the grass, boss, aren't you ninety-five? Think of a way!"

"I'm learning advanced mathematics, and I'm not learning how to go to heaven!"

"Designing a table... What can a table design, isn't it just four legs? It can be folded... Let's put a spring behind the legs of the stool?"

It was quite lively in the computer room, and it could be seen that the students were so confused by this question that they had no idea how to start.

But there are also experts in it.

For example, Luo Rundong, the second student in Lu Zhou's class, is now quietly communicating with his teammates.

And Liu Rui... This kid's team seems to have a very reliable thigh. Now he has finished reading the topic and started to assign work to two teammates.

Looking at the two questions downloaded from the official website, Wang Xiaodong frowned.

Heaven collapsed.

Both questions are related to physics.

The previous one involves orbital calculations in aerospace physics, and high school physics knowledge alone is definitely not enough. Question B is very simple on the surface, but it is not much easier than the first question. It involves the dynamic motion analysis of the table legs, involving A series of problems, such as material force analysis, not only involve mathematical modeling knowledge, but also require a certain dabbling in structural mechanics, materials science and even ergonomics.

However……

The "mathematical genius" in the team was just in his second year of sophomore year and even just started his physics class.

There's no other way, just avoid it.

The first one cannot be done with insufficient physical knowledge, and the second one can collect data through the Internet and find ways to convert it into mathematical problems to solve.

Wang Xiaodong looked at Lu Zhou, "Do you want to choose question B?"

Lu Zhou shook his head: "Choose question A."

"Question A?" Wang Xiaodong frowned, "Are you okay?"

"As for college physics, I've already finished it. Although aerospace physics seems complicated, in the final analysis, it's just the content of the first three chapters." After a pause, Lu Zhou glanced at the team next to him and continued, "Also, look In this computer room alone, there are enough people who choose question B."

Questions AB are selected separately. Under such a scary situation as question A, there are bound to be many candidates for question B. At this time, it is time to show the courage of "knowing that there are tigers in the mountains, but prefer the tigers to the mountains", leave the single-plank bridge to thousands of troops, and walk on your own Yangguan Avenue smartly!

Of course, this was also the choice that Lu Zhou made when he was sure about question A in his heart.

Wang Xiaodong nodded expressionlessly, and naturally understood the meaning of Lu Zhou's last sentence.

"That's fine, I'll leave the modeling to you."

"I will handle it."

Eye contact, the two scholars have reached a consensus.

Lin Yuxiang looked at the two teammates who had reached an agreement with a confused expression, and couldn't help asking weakly, "That...is there anything I can help?"

Wang Xiaodong showed a smile that he thought was very gentle and said that he was just about to say "just leave it to me" handsomely, but before he could feel the emotion on the paralyzed face, he was burying his head in the draft on A4 paper. Lu Zhou, without raising his head, said unceremoniously: "Bring food, water, please."

There is no shortage of people in modeling, programming, and papers, and there is no shortage of errands.

Don't think that lying down is so easy to lie down. If you don't let this guy do some work, Lu Zhou's heart is unbalanced.

Wang Xiaodong: "..."

Lin Yuxiang didn't complain at all, and nodded vigorously: "Mmmm, it's on me!"

The advantage of mathematical modeling and thesis writing done by one person is that many tasks that require two people to communicate can be done by one person, and there are no problems such as teammates' tacit understanding and ability to express and understand.

At the same time, under the circumstance of grasping the modeling paper, Lu Zhou, as the captain, can accurately give orders to Wang Xiaodong, who is in charge of programming.

In this way, there are almost no differences of opinion among the team members!

Beyond the stem information, there are three questions:

(1) Determine the positions of the perilunar and apolunar points of the landing preparation orbit, as well as the magnitude and direction of the corresponding speed of Chang'e-3.

(2) Determine the landing orbit of Chang'e-3 and the optimal control strategy in 6 stages.

(3) Do the corresponding error analysis and sensitivity analysis for the landing orbit and control strategy you designed.

"The abstract part is a summary of the full text. This part can be completed after the entire article is written. The focus is on the problem analysis after the problem restatement, which involves all the ideas of the entire modeling. The soul of the entire paper is here. ." Biting the ballpoint pen, Lu Zhou tapped the keyboard with his fingers, wrote the outline of the thesis, and then began to define the most critical soul for his thesis based on the previous draft.

[Question 1, in order to obtain the positions of the perilunar and apolunar points in the preparation orbit for the landing, as well as the magnitude and direction of the corresponding velocity of Chang'e-3, first use the knowledge of mechanics and the known conditions to calculate. Using extreme thinking, the motion in the main deceleration stage of Chang'e-3 is divided into infinite linear motions with uniform speed. Use Matlab software to design a program to iteratively calculate the main deceleration stage...]

[Question 2, in order to ensure the landing orbit of Chang'e-3 and the optimal control strategy in the 6 stages, it is necessary to aim at the minimum fuel consumption. On this basis, conduct analysis, use the parameters obtained from question 1, and use Matlab software to identify numbers The algorithm of obstacles in the elevation map realizes the identification of obstacles and the positioning of landing points, and simulates the optimal landing trajectory by establishing a model...]

[To analyze the error of the landing orbit control strategy designed in Question 2, we must first enumerate all the factors that may cause the error, and analyze them...]

Lu Zhou, who entered the state, was highly focused on the topic in front of him.

When he finished analyzing the problem, he only felt that his brain was very awake, and he even formed a general framework in his mind for the writing ideas of the entire thesis.

The rest of the work is to translate this outline into the language of mathematics...

For most teams, the paper is usually placed after modeling and programming are completed, but for Lu Zhou, the two can be carried out simultaneously!

This will be the biggest advantage of their team!