Optimizing Brake Blending Strategies for Various Electric Vehicle Layouts Using a Quasi-Static Approach

The growing electrification of modern vehicles brings new challenges in achieving an effective balance between regenerative energy recovery and vehicle stability, particularly during braking maneuvers. While most research efforts have historically focused on traction-oriented torque vectoring to enhance acceleration and handling, the braking phase — where the potential for energy regeneration is greatest — has received comparatively limited attention. This thesis addresses this gap by examining how the choice of understeer characteristic (UC) and drivetrain architecture influences regenerative braking performance during the vehicle design phase. To support this investigation, a quasi-static simulation framework for brake torque vectoring was developed. The tool combines brake blending logic, UC-based control strategies, and drivetrain-specific mechanical constraints within a unified environment. It provides a simplified yet physically consistent representation of several powertrain configurations — including single-motor per axle (SMA) systems, open (OD) and limited-slip (LSD) differentials, and in-wheel motor (IWM) architectures — all reformulated into analytical relationships suitable for control allocation studies. The simulation process begins with the identification of feasible operating regions for given longitudinal speeds and deceleration levels. Within these regions, custom understeer characteristics are defined to represent different design philosophies, ranging from sport-oriented to energy-efficient behaviors. The results are then analyzed comparatively to assess how each drivetrain configuration influences both stability and energy recovery under varying dynamic conditions. The analysis reveals that no single configuration is universally superior. SMA layouts generally achieve the highest regenerative power, while IWM architectures offer greater flexibility in scenarios requiring asymmetric torque distribution or positive torque demand. LSD systems provide clear advantages under stabilizing yaw moments, but behave similarly to OD configurations once the electric motor reaches saturation. Beyond the analytical findings, the developed tool offers a practical design platform. Through its graphical interface, users can generate lookup tables (LUTs) defining optimal torque allocation strategies, which can be directly implemented within an electronic control unit (ECU). In summary, this work provides a structured methodology to evaluate whether design efforts should prioritize the definition of the understeer characteristic or the drivetrain configuration when the objective is to maximize regenerative braking efficiency, offering insights that bridge the gap between theoretical modeling and practical vehicle control design.