Trolley synchronizing mechanism, system and control method

The invention discloses a trolley synchronizing mechanism and system and a control method. The trolley synchronizing mechanism comprises a support, a driving device, a roller rod, an encoder and two rollers, the driving device is fixed to the support, the roller rod is hinged to the support, the two rollers are hinged to the two ends of the roller rod respectively, and the driving device is connected with the roller rod and drives the roller rod to rotate clockwise or anticlockwise around the support. And at least one encoder is connected with the roller and synchronously rotates along with the roller. The roller rod and the rollers are arranged, the roller rod is driven to rotate clockwise or anticlockwise, so that one roller is in contact with the trolley, the advancing speed of the trolley is detected through the encoder synchronously rotating with the rollers, and due to the two rollers, when one roller is separated from the trolley, the trolley can be driven to rotate clockwise or anticlockwise. The roll