Abstract: Under traditional PI parallel control strategies，synchronous control systems of multi-motor rigid

connection structure have the problem of unbalanced motor torque output，and there is even a serious risk of shaft

breakage. Taking the rigid connection structure of multi-motor gear transmission as the research object，a gearmotor coupling model was established. According to the strong coupling characteristics of the model，the

influencing factors of torque error were analyzed，and then a multi-motor torque balance control strategy based on

the idea of deviation coupling was proposed. By synthesizing all motor output torque information and selecting an

appropriate coupling gain coefficient，the control strategy compensates the motor torque to achieve a balanced

output of motor torque. Compared with the simulation of a traditional PI parallel control strategy，the proposed

scheme can effectively reduce the torque error among motors，and the torque output fluctuation caused by rigid gear transmission structure tends to be gentle.

      Key words: multi-motor synchronization；rigid connection；deviation coupling；torque equalization