基于路面影响因子的轮毂电机驱动车辆自适应转矩控制

为实现轮毂电机驱动越野车辆在附着条件多变、路面起伏不定的复杂环境中动力性和稳定性的多目标优化，提出一种基于路面影响因子的自适应转矩控制策略。以滚动阻力差异、空气阻力归一化比例、坡度阻力归一化比例、路面附着差异方差以及最小路面附着系数5个特征参数作为输入，并基于模糊理论方法搭建路面影响因子五参数辨识模型。基于辨识出的路面影响因子，开发整车动力性和稳定性多目标优化自适应转矩控制策略，构建了三层式控制架构：顶层引入路面影响因子对加速度紧迫程度进行判定，采用模型预测控制算法得到期望总驱动力；中层为目标决策层，以最优滑转率为目标决策驱动防滑力矩，并基于路面行驶阻力，决策期望前馈补偿力矩；下层为转矩分配层，以需求总驱动力及轮胎利用率作为控制目标，引入路面影响因子优化两者权重系数，以多约束条件的混合优化算法对转矩进行自适应控制。利用Matlab/Simulink-CarSim联合仿真平台进行仿真，基于实车进行验证。结果表明，在低附着路面，在0.2 s内快速完成滑转率抑制；在对开路面，侧向位移接近0；在大扭曲路面，避免腾空车轮出现大滑转率，滑转率最高0.2。

Adaptive Torque Control In-Wheel-Motor Driven Vehicles Based on Pavement Impact Factors

To achieve multi-objective optimization of power performance and stability for in-wheel-motor driven off-road vehicles in complex environments with variable adhesion conditions and undulating road surfaces, the paper proposed an adaptive torque control strategy based on pavement impact factors. Five characteristic parameters, namely, the difference in rolling resistance, normalized proportion of air resistance,normalized proportion of ramp resistance, variance of road adhesion difference and the minimum road adhesion coefficient, were used as inputs to establish a five-parameter identification model of pavement impact factors based on fuzzy theory. Considering the identified pavement impact factors, an adaptive torque control strategy was developed for the multi-objective optimization of vehicle power performance and stability, and a three-layer control architecture was constructed. At the top of the strategy, the pavement impact factors are introduced to determine the urgency of acceleration, and the model predictive control algorithm is used to obtain the desired total driving force. The middle layer serves as the target decision-making layer, which governs the anti-skid torque based on the optimal slip rate, and determines the desired feedforward compensation torque according to the road resistance. The base layer servers as the torque distribution level, taking the total demand driving force and the tire utilization ratio as the control objectives.It introduces the pavement impact factors to optimize the weight coefficients of these two objectives. A hybrid optimization algorithm with multiple constraints is applied for adaptive torque control. Simulations were conducted using the Matlab/Simulink-CarSim co-simulation platform, with real vehicle trials for verification. The results show that on low-adhesion road surfaces, the wheel slip control can be achieved rapidly within 0.2 s. On the split road surfaces, the lateral displacement is nearly negligible, showing excellent lateral stability. On highly twisted road surfaces, the system prevents large slip rates of the free-spinning wheel from exceeding 0.2.