Adaptive Energy-Efficient Control Allocation for Planar Motion Control of Over-Actuated Electric Ground Vehicles

A hierarchical control structure, consisting of a high-level dynamic sliding mode control (SMC) and a low-level adaptive energy-efficient control allocation (A-EECA) scheme, is presented to track the planar motions of an electric ground vehicle with four in-wheel motors while achieving the optimal energy consumption. By explicitly incorporating the efficiency functions and input constraints of in-wheel motors in the low-level A-EECA design, virtual control signals from the high-level dynamic SMC are distributed to four actuators with an adaptive convergence to the energy-optimal operating points. Taking allocation errors between the virtual control efforts and the real actuation realizations as inputs, the input-to-state stability of the overall feedback system is proved. Both simulation and experimental results in different maneuvers are demonstrated to validate the control design. The high-level vehicle tracking performance, low-level torque distributions, and total energy consumptions in the test maneuvers are compared between the proposed A-EECA and a standard pseudoinverse control allocation without considering the power optimization.