On April 29, 2021, the Chinese space station Tianhe core module was launched! The whole country rejoiced.
Inside the Beijing Aerospace Flight Control Center, a tall, thin man with a furrowed brow, wearing a headset, stared at the screen. Heaven and earth interact, gripping. With the successful implementation of tasks such as unlocking the space station's robotic arm, crawling in orbit and out-of-cabin inspection, the young man stood up and hugged his colleagues with excitement and tears. It worked!
The young man's name is Liang Changchun, 34 years old, the chief designer of the mechanical arm control system of the space station of the Fifth Academy of Aerospace Science and Technology Group. For nearly a decade, his youth has been dedicated to this space "changeable god arm".
The association with aerospace is a beautiful "accident". Before graduating from Tongji University with a master's degree, Liang Changchun accompanied the student to participate in the propaganda meeting of China Aerospace Science and Technology Group, which ignited the dream of spaceflight.
After entering the overall design department of the Fifth Academy of Aerospace, Liang Changchun quickly received a "big order" - installing a "brain" for the Chang'e-5 sampling robot arm. Aerospace products have strict weight limits, and while "weight reduction", it is also necessary to ensure that the movement is fine in millimeters. This slender robotic arm like a fishing rod gave the team a big problem.
There is no precedent to follow, Liang Changchun plunged into the laboratory, more than a year, repeatedly pushed down, experimented, and finally wrote thousands of lines of MATLAB program code, forming the first generation of SPACE robotic arm control algorithm SIMULINK model library.
Chance, only once! There can be no mistakes. After Chang'e 5 landed on the moon, the time to complete the lunar mission was only 48 hours.
In order to be foolproof, Liang Changchun simulated the lunar environment, experimented hundreds of times, and prepared all conceivable failures. Uncertain about the density of the lunar soil, they set a variety of parameters to let the "arm" adjust the "force" according to the touch. Deep drilling, shallow drilling, shoveling, digging, and sandwiching soil, about 1.7 kilograms of "Moon Palace Specialties" are encapsulated and brought back.
The challenges are endless.
Since 2016, Liang Changchun has simultaneously designed a control system for the large robotic arm of the Chinese space station. This "Hercules Arm" must be able to carry a large 25-ton module, but also be able to quickly and dynamically capture hovering aircraft. However, the carrier rocket has restrictions on the size of the robot arm, and the light weight and flexibility and the full coverage of the working surface have become a contradiction.
Every day he was "brainstorming", the drawings were like snowflakes, Liang Changchun even dreamed of a mechanical arm, and his family said that he was already "magic". Finally, one day, the team took inspiration from the drawing compass to design two feet (hands) for this robotic arm - an end effector, a brain - a central controller, and 7 joints, the most realistic restoration of the human arm. Leaning against the "footprints" (target adapters) set on the bulkhead, this arm is more than ten meters long and can even cover the entire cabin to "crawl".
Every leap has to go through countless times of bulldozing and restarting. Liang Changchun said that "returning to zero" is the most torturous, and when there is a problem in the experiment, they must trace the source, learn from each other, and start again. In the field of aerospace science and technology, there is a word called "the back wall does not fall", which means that we must "conquer the mountain" at the specified time. Therefore, every "zeroing" means working overtime and catching up with progress.
In order to ensure that the robotic arm flight program is foolproof, a total of 23 versions of the key flight procedures have been drafted before and after. Liang Changchun often deduced the procedure until the middle of the night, and could not go home, but his wife could only take on the heavy responsibility of taking care of the young children. In his view, aerospace engineering can not tolerate failure and regret, "only a perfect process can lead to a perfect result." ”