The force transmitted from the front tires to the steering rack of a vehicle, called the rack force, plays an important role in the function of Electric Power Steering (EPS) systems. Estimates of rack force can be used by EPS to reduce driver effort and enhance driving performance. Further, estimates of the components of rack force can be used to perform targeted compensation to enhance steering feel and vehicle safety. Existing rack force estimators either do not support the estimation of rack force components or are only applicable for driving on flat roads. This paper presents three vehicle and tire model-based rack force estimators that can estimate individual components of rack force as well as the total rack force for driving on uneven roads. The estimators use the same vehicle model but use tire models of differing complexities. The performance of the estimators was validated and compared by performing driving experiments with non-aggressive and aggressive steering maneuvers on roads with low and high frequency profile variations. The results show that the estimation accuracy increases with the complexity of tire model used, especially during aggressive steering maneuvers and high frequency road profile variations. Finally, results from a simulation study are presented to show that the estimators are also capable of estimating the components of rack force.

从前轮胎传递到车辆转向齿条的力，称为齿条力，在电动助力转向 (EPS) 系统的功能中起着重要作用。EPS 可以使用齿条力的估计值来减少驾驶员的努力并提高驾驶性能。此外，齿条力分量的估计可用于执行有针对性的补偿，以增强转向感和车辆安全性。现有的齿条力估计器要么不支持齿条力分量的估计，要么仅适用于在平坦道路上行驶。本文介绍了三种基于车辆和轮胎模型的齿条力估计器，它们可以估计齿条力的各个分量以及在不平坦道路上行驶的总齿条力。估算器使用相同的车辆模型，但使用不同复杂性的轮胎模型。通过在具有低频和高频剖面变化的道路上进行非攻击性和攻击性转向操作的驾驶实验，验证和比较了估计器的性能。结果表明，估计精度随着所用轮胎模型的复杂性而增加，特别是在激进的转向操纵和高频道路轮廓变化期间。最后，模拟研究的结果表明估计器也能够估计齿条力的分量。尤其是在激进的转向操作和高频路况变化期间。最后，模拟研究的结果表明估计器也能够估计齿条力的分量。尤其是在激进的转向操作和高频路况变化期间。最后，模拟研究的结果表明估计器也能够估计齿条力的分量。