With the advancement of control technology in the automotive field, there is a
possibility of cross-system redundant control between various actuators. As for
the braking system, current brake-by-wire system often uses mechanical backup
braking methods to give the vehicle a certain braking capacity after failure.
However, in the mechanical backup braking mode, the brake master cylinder is
connected to the supporting wheel cylinder, and the brake assist is lost, which
leads to an increase in brake pressure and makes it difficult for the driver to
step on the brake pedal. Meanwhile, due to the limitation of the brake master
cylinder stroke, the maximum braking deceleration of the vehicle is only 3
m/s2 after the driver fully presses the brake pedal. The above
two defects greatly affect the safety of the vehicle during backup braking. To
solve the above problems, this article takes electric vehicles as the research
object, designs a new type of hydraulic circuit for the braking system, and
develops a backup braking method that integrates the drive motor and electronic
parking system. This article builds a vehicle simulation model and selects real
vehicles for actual testing. The results showed that in backup braking mode, the
driver obtained the braking sensation during normal braking, and the maximum
braking deceleration of the vehicle reached 10 m/s2. Overall, the
backup braking method designed in this article effectively solves the drawbacks
of the current brake-by-wire system and improves the safety of vehicles during
backup braking.
