Coordination of Vehicle Motion and Energy Management Control Systems for Wheel Motor Driven Vehicles

Abstract

This paper shows how smooth coordination of vehicle motion controller and energy management can be achieved when control allocation is used for over-actuated ground vehicles. The ground vehicle studied here is equipped with four electric wheel motors, four disc brakes, and front and rear steering. This gives a total of ten input signals to control the desired vehicle motion in longitudinal-, lateral-, and yawdirection. Simulations show that the desired input signals from energy management and steering can be fulfilled, but when needed the actual input signals for the motion actuators are smoothly diverted from the desired input signals due to vehicle stability reasons and/or saturation of the actuators.

A stochastic power management strategy with skid avoidance for improving energy efficiency of in-wheel motor electric vehicles

“…Another powerful technique for the IWM-EV power management problem is control allocation which was basically developed to distribute the desired total control effort among a redundant set of actuators for an over-actuated system. [17][18][19][20][21] Optimal control approaches using the Pontryagin's minimum principle are other candidates for online power management optimization. 26 For deterministic driving scenarios and power demand profiles, DP is an excellent off-line technique to find the optimal power or torque distribution; but in the real-world problems, the future driving power demand is uncertain and dependent on the road traffic, terrain profile, weather, and so on.…”

“…Another powerful technique for the IWM-EV power management problem is control allocation which was basically developed to distribute the desired total control effort among a redundant set of actuators for an over-actuated system. 19–23 Optimal control approaches using the Pontryagin’s minimum principle are other candidates for online power management optimization. 28…”

“…A good review of the current IWM-EV power management strategies is presented by Liu et al 16 Power management based on IWM efficiencies have been investigated in several published works. [17][18][19][20][21][22][23] Qian et al 24 proposed one time-step horizon simple search optimization algorithm for the front and rear IWMs torque distribution and achieved up to 27.4% reduction in the power consumption in comparison with a traditional EV. IWM-EV energy optimization using the dynamic programming (DP) algorithm based on terrain profile preview was investigated for constant speed driving situations 25 and a specific traffic model.…”

Robust cascade control for the horizontal motion of a vehicle with single-wheel actuators

“…[6][7][8][9][10] These approaches use the over-actuation either for safety maximisation [11][12][13] or for energy minimisation. [14] Since the necessary numerical optimisations are time consuming, an analytical tyre force allocation is described in [15] allowing for real-time application. In [16,17] interesting approaches are described to allocate the tyre forces while taking actuator failures into account.…”

Coordinated control of multi-actuated electric vehicle

“…reference control inputs of actuators (brake pressure / torque, drive torque, steering angle) [48,49]. Both, tasks, such as force allocation and subsystem coordination, can be solved jointly;…”