For distributed drive electric vehicles (DDEV) equipped with an electronic
hydraulic braking system (EHB) and four-wheel hub motors, when one or more hub
motors have regenerative braking failure, because the braking torque of the four
wheels is inconsistent, additional yaw moment will be formed on the vehicle,
resulting in the loss of directional stability of the vehicle during braking. If
it occurs at high speeds, it will further threaten driving safety. To solve the
above problems, a new hierarchical control architecture is established in this
paper. Firstly, taking DDEV as the research object, the vehicle dynamics model
and EHB braking system model are built. Then, a state observer based on an
adaptive Kalman filter is designed in the upper layer to estimate the vehicle’s
sideslip angle and yaw rate in real time. In the judgment decision-making layer,
the phase plane is used to divide the stability domain boundary of the vehicle,
and the quasi-stability tolerance band judges the vehicle’s driving state.
Secondly, the lower stability controller is constructed based on the sliding
mode control theory. EHB can flexibly distribute hydraulic braking force to
compensate for the vehicle’s braking force, offset the additional yaw moment,
and maintain the straight line of the vehicle. Finally, experimental
verification is carried out in Matlab/ CarSim and hardware-in-the-loop (HIL)
platforms. The results show that the proposed method can effectively predict the
state and closed-loop stability control of DDEV, and reduce the deviation
distance caused by regenerative braking failure, effectively ensuring the
vehicle in the event of regenerative braking failure driving safety.