Tiangong robotic arm spacewalks

Last year, the United States on-line a U.S. Pacific Air Force construction as the theme of the comedy "Space Force", in the parallel world of the play, was arranged as the United States "imaginary enemy" of China's space technology is incredibly powerful, from the use of robotic arms to cut the Americans' satellite panels, captured the U.S. Astronauts chimpanzees to the moon to set up a large-scale base first, simply Everything is possible.

What is even more laughable is that the reality of the U.S. military also followed along with the "dream", committed a persecution paranoia. Not long ago, Dickinson, commander of the U.S. Space Command, claimed that China had a satellite equipped with a robotic arm that could "grab" U.S. satellites.

When China's Shenzhou 12 spacecraft went into space, there was one thing that attracted the world's attention, and that was the space robot arm on the Shenzhou 12 spacecraft. China's mechanical arm is very advanced, he is not fixed in the spacecraft, but can crawl and move outside the spacecraft! Doesn't it shock our brain's imagination? It can adjust its position as needed, so how is this done? In fact, it is very simple, that is, both ends of this mechanical arm can be connected to the airship body, the need to move the mechanical arm, one side to grab the airship, the other side of the release, and then move the mechanical arm, it is no wonder that it can make the United States of America delusional.

However, at the same time in the pride, we must know, in fact, this high degree of freedom can crawl space robot arm is not unique to China. At present, there are only four countries in the world can independently complete the construction of space robotic arm, we will look at the European Union as a country, that is, the European Union, Canada, Japan and China.

Canada's robotic arm of the global technological level of the cutting edge, out of the first generation, out of the second generation, but still not fully automatic. The United States now also has no ability to engage in mechanical arm, it is used in Canada's products. 2001 Canada launched the second generation of space robot arm, called SSRMS, total length of 17.6 meters, diameter of 0.38 meters, gripping load of 116 tons, is currently for the advanced space robot arm. Canada's mechanical arm's functions include: maintenance, installation of space station components, launching and grappling satellites, it has 29 times grappled the space shuttle, but also many times grappled SpaceX's cargo and manned spacecraft.

Apparently, the robotic arm described in the U.S. Space Force clipping the wings of satellites is more suited to Canada's robotic arm, which the Americans planted on the heads of the Chinese with ulterior motives.

There is also Europe is also engaged in mechanical arm, but not counting a country but nine countries jointly developed, but has been delayed for nine years, finally waited until July 15 ready to launch, but the result is delayed again, when it can be in the sky is still unknown for the moment. Russia's simple and rough, directly on the "fish pole", Russia launched the "Science" on the experimental module, there is also a mechanical arm, it also has 7 degrees of freedom and can crawl function. However, this arm is not produced in Russia, but the European product ERA, which will be used as a "spare tire" for the Canadian arm 2 after it enters space. In Japan, it is a small robotic arm that can't be moved, and it has accomplished its mission.

China's space mechanical arm began to develop in 2005, the development was completed in 2008, 2016 space use, the length of 10.2 meters, and ask the sky experimental module mechanical arm combination after the length of 15 meters, second only to the Canadian 2, grabbing the planted load of 25 tons, the use of life for 10 years. China's space station mechanical arm system called CSSRMS, in fact, is divided into two sections, one is ten meters long based on the core module development of the main arm CMM, a section of five meters long, the original plan based on the development of the experimental module vice arm EMM, like two arms can be left and right, can also be strung together as a long arm to use.

"Heaven and" the core module outside the pair of large mechanical arm, for China's professional with seven degrees of freedom of the mechanical arm, so that in space can be realized similar to the human arm of the movement ability, so what is seven degrees of freedom?

Theoretically, the three-dimensional space of the rigid body needs three-dimensional coordinates xyz plus three rotation angles totaling six degrees of freedom, and seven degrees of freedom is equivalent to more than one redundant degrees of freedom, so that the robotic arm can be more flexible posture to reach a certain point. Let's say, the same is to screw the key, 6 degrees of freedom of the robotic arm in space will not be able to keep the shoulder and hold the key hand does not move in the case, from a configuration change to another configuration, and 7 degrees of freedom can be.

Objectively speaking, the Chinese Tiangong robotic arm is much more capable than the 7 degrees of freedom 11-meter-long robotic arm ERA that ESA and the Fighting Nation Space Agency (RSA) have joined forces to build, but it is worse than the 35-centimeter-diameter Canada 2 arm in three ways: mobility, strength, and end hand, but after all, the Chinese one is only 738 kilograms, while the Canada 2 arm is 1.8 tons.