MPC-based Torque Distribution for Planar Motion of Four-wheel Independently Driven Electric Vehicles: Considering Motor Models and Iron Losses

The most critical obstacle for four-wheel independently driven electric vehicles (4WID-EVs) is the driving range. Being the actuators of 4WID-EVs, motors account for its major power consumption. In this sense, by properly distributing torques to minimize the power consumption, the driving range of 4WID-EV can be effectively improved. This paper proposes a model predictive control (MPC)-based torque distribution scheme, which minimizes the power consumption of 4WID-EVs while guaranteeing its tracking performance of planar motions. By incorporating the motor model considering iron losses, the optimal torque distribution can be achieved without an additional torque controller. Also, for this reason, the proposed control scheme is computationally efficient, since the power consumption term to be optimized, which is expressed as the product of the motor voltages and currents, is much simpler than that derived from the efficiency map. With reasonable simplification and linearization, the MPC problem is converted to a quadratic programming problem, which can be solved efficiently. The simulation results in MATLAB and CarSim co-simulation environments demonstrate that the proposed scheme effectively reduces power consumption with guaranteed tracking performance.