Dual-motor steer-by-wire system and synchronous control method thereof

The invention discloses a dual-motor steer-by-wire system and a synchronous control method thereof, and the system comprises a steering wheel angle sensor which is used for obtaining a steering wheel angle signal and transmitting the steering wheel angle signal to a variable transmission ratio module; the vehicle control unit comprises a variable transmission ratio module and a virtual main shaft synchronous controller; the steering actuator comprises a steering motor, a steering motor speed reducer, a pinion, a steering motor controller, a current Hall sensor, a Hall sensor, a rack, a steering tie rod, a left front wheel, a right front wheel and a vehicle speed sensor; according to the method, parameter perturbation, load nonlinearity and time-varying and time-lag existing in the dual-motor steer-by-wire system are adaptively controlled, an adaptive nonsingular fast terminal disturbance controller and a super-spiral optimal time-lag compensator are designed, and meanwhile, a disturbance value observed by an