1. MPC based Rear Wheel Torque Vectoring Near the Limits of Handling
Efstathios Siampis
Dr Efstathios Velenis, Dr Stefano Longo
Cranfield University
UKACC PhD Presentation Showcase

2. UKACC PhD Presentation Showcase
Introduction
Velocity regulation becomes important in terminal understeer cases
Design an active safety system that:
Stabilizes the vehicle using combined velocity, yaw and sideslip control
Accounts for the important in limit handling conditions system constraints
UKACC PhD Presentation Showcase

3. UKACC PhD Presentation Showcase
Approach to Problem
Rear wheel torques -
MPCs
Driver Intention
RWD Vehicle
Driver inputs (using the steering, throttle, and brake pedal)
Velocity, sideslip angle and yaw rate +
UKACC PhD Presentation Showcase

4. Approach to Problem: Target Generation
Steady state cornering analysis of a nonlinear four-wheel vehicle model to derive feasible targets
Then the requested path radius 𝑅 𝑘𝑖𝑛 from the driver can be feasible, or not -
MPCs
Driver Intention
RWD Vehicle +
UKACC PhD Presentation Showcase

5. Approach to Problem: Controller Design
For the MPC, we linearize the nonlinear four-wheel vehicle model and use the rear wheel slip as inputs
Constraints are set on yaw rate and sideslip angle, but also on the rear wheels’ slip ratios and torques
Then a sliding mode controller calculates the necessary torques on the rear wheels
MPC
SMC
Rear wheel slip ratios
Rear wheel torques -
MPCs
Driver Intention
RWD Vehicle +
UKACC PhD Presentation Showcase

6. Simulations: U-turn scenario
Uncontrolled
LQR
MPCs
UKACC PhD Presentation Showcase

7. Simulations: Double-lane Change Scenario
Uncontrolled
LQR
MPCs
UKACC PhD Presentation Showcase

8. Conclusions and Future Work
Lateral control only not enough for terminal understeer mitigation
Accounting for the system constraints can prevent instability
Future Work
Exploration of different vehicle topologies
Controller testing in the HIL facility of the Automotive Department
UKACC PhD Presentation Showcase