Control method and control system for rotary joint system in multiple-car construction elevator

The invention provides a control method and control system for a rotary joint system in a multiple-car construction elevator. The control method comprises the following steps: resetting an absolute value encoder used for detecting the rotation position of the rotary joint and resetting the rotary joint, and controlling the rotary joint with cars to be rotationally positioned; after the rotary joint with the cars is rotationally positioned, analyzing a signal of an upward side detection device and a signal of an downward side detection device, and judging the running side of the cars. The control method realizes that the rotary joint automatically completes precise rotational positioning, ensures that the rotary joint closely coincides with standard joints above and under the rotary joint after being rotated, ensures that the cars are safe and stable when lift and pass through the rotary joint, meanwhile prevents the rotating cars from colliding with a building body, and improves the running safety of the whole multiple-car construction elevator.