Abstract: A dual-mode active rear-wheel steering device, including: a steering angle control motor, a speed-reduction mechanism, a differential mechanism assembly, two steering motion conversion mechanisms, a first electromagnetic clutch and a second electromagnetic clutch. An output end of the steering angle control motor is connected to the speed-reduction mechanism. The differential mechanism assembly is a bevel gear differential, in which center holes at outer ends a two half shafts are respectively provided with a raceway to form an inner cyclical ball-lead screw-nut pair with a first lead screw and a second lead screw of the steering motion conversion mechanisms. The first lead screw and the second lead screw are the same in parameters but with opposite rotation direction. The first electromagnetic clutch controls connection between a differential housing and a frame. The second electromagnetic clutch controls connection between the differential housing and the second half shaft.

Abstract: A dual-mode active rear-wheel steering device based on a multi-linkage mechanism, including: a steering angle control motor with a speed-reduction mechanism, a multi-linkage mechanism assembly for converting rotational motion of the steering angle control motor into linear motion of an end of the push rod, a steering actuating mechanism for converting linear motion of the multi-linkage mechanism assembly into rotation of a knuckle around a kingpin to make the rear wheels steer, a first electromagnetic pin puller and a second electromagnetic pin puller respectively configured to control a first extendable-retractable push rod assembly and a second extendable-retractable push rod assembly to work at a fixed or variable axial length. The device uses the steering angle control motor to drive the two rear wheels to turn in the same direction or opposite directions through the control of energized state of the two electromagnetic pin pullers.

Abstract: An electric multi-mode steer-by-wire system and a mode switching method thereof. The electric multi-mode steer-by-wire system includes a steering hand wheel unit including a steering hand wheel, a road-feeling motor, a reducer and an electromagnetic clutch, a steering execution unit including two steering electric motor mechanisms, a steering gear and two steering road wheels, an electronic control unit configured to control the steering hand wheel unit and the steering execution unit to achieve switching among two-side steering-road-wheel independent steer-by-wire mode, steering-trapezoidal steer-by-wire mode and electric power steering mode, and a mode selection and display unit. The electromagnetic clutch connected to the steering execution unit.