Redundant motor direct-drive brake-by-wire device for autonomous vehicle and control method

The invention relates to a redundant motor direct-drive brake-by-wire device of an automatic driving automobile and a control method. The invention discloses a redundant motor direct-drive brake-by-wire device of an automatic driving automobile. A gear ring is fixed on a gear ring output frame; an output shaft of the gear ring output frame is a cylinder internally provided with a through hole, the outer portion of the output shaft is coaxially and fixedly connected with the gear, the inner portion of the output shaft is connected with an input shaft of the planet carrier, and the gear ring output frame and the planet carrier can rotate relatively. A planet gear on the planet carrier is internally meshed with the gear ring and externally meshed with a sun gear, the sun gear is connected with an output shaft of a sun gear motor, and an input shaft of the planet carrier is connected with an output shaft of a planet carrier motor; the rack is meshed with the gear, and an output shaft of the rack is connected with