Manufacturing method of rotor assembly, rotor assembly and multi-redundancy angular displacement sensor

The invention relates to the field of angular displacement sensors, in particular to a manufacturing method of a rotor assembly, the rotor assembly and a multi-redundancy angular displacement sensor. The manufacturing method of the rotor assembly comprises the following steps: assembling an intermediate product; finish machining is conducted on the first preset position, the second preset position, the third preset position and the fourth preset position of the intermediate product according to the same axis line through the external grinding technology; and obtaining the rotor assembly. The intermediate product is arranged on the grinding machine, the first preset position, the second preset position, the third preset position and the fourth preset position of the intermediate product are subjected to finish machining through the grinding machine in an outer circle grinding mode, and therefore the overall error of the intermediate product is reduced, and the overall straightness of the intermediate product i