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紧急避障工况下的驾驶人操作具有响应快且动作幅值较大的特点,传统预瞄驾驶人模型已不能适应紧急避障工况的需求,故考虑实际避撞场景开发相应的驾驶人模型就显得尤为必要。针对此种状况,基于驾驶模拟器,结合紧急避撞工况实际驾驶人操纵数据,提出了一种融合预瞄与势场栅格法的紧急避撞驾驶人模型。首先针对紧急避撞工况下车辆运动特点,建立车辆横、纵向耦合非线性动力学模型,并给出其状态空间方程描述;其次,离线仿真分析紧急避撞系统特征,并结合线性二次型最优控制,建立最优曲率预瞄+跟踪误差反馈驾驶人模型;再者,基于紧急避撞工况下真实驾驶人经验转向行为数据,开发基于势场栅格法的驾驶人模型,为进一步提高驾驶人模型对避障行驶工况的适应性,将基于势场栅格法的驾驶人模型与最优曲率预瞄+跟踪误差反馈驾驶人模型进行融合,并基于Sigmoid函数实现两者输出的权重分配;最后,针对所提出的融合预瞄与势场栅格法的驾驶人模型,开展基于避撞台架的驾驶人在环仿真试验以及实车试验。研究结果表明:在紧急避撞工况下,对比最优曲率预瞄+跟踪误差反馈驾驶人模型,融合预瞄与势场栅格法的驾驶人模型输出的转向动作与实际驾驶人行为较为接近,可在保证避障安全性的前提下,兼顾避障路径跟踪精度与车辆行驶的稳定性。 相似文献
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《汽车工程》2017,(7)
提出了两层驾驶员转向预测模型,基于驾驶员视觉预瞄信息的第一层体现了路径跟踪特性,基于神经肌肉动力学模型的第二层体现了驾驶员转向操作特征,采用Car Sim/Simulink对比了不同状态驾驶员的路径跟踪性能。设计了车道偏离防避系统(LDAS)的期望横摆角速度观测器和转角PID控制器。建立了转向系统等效动力学模型,并基于滑模理论设计了LDAS的鲁棒转矩控制器。由于车辆偏离车道程度与预瞄点的侧向偏移量和驾驶员力矩的关系不能精确描述,故基于模糊控制理论设计了LDAS人机共驾模糊控测器。进行了基于Car Sim/Simulink的仿真和基于Car Sim/Lab VIEW RT的硬件在环试验,对比了驾驶员、LDAS控制器和人机共驾纠正车辆偏航的能力。结果表明,所提出的人机共驾策略能及时纠正车辆偏航,使之恢复到正常车道,并保证从人机共驾到驾驶员控制切换过程的平顺性。 相似文献
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无人驾驶汽车路径跟踪控制是无人驾驶汽车运动控制的核心所在,目前常用的路径跟踪模型主要以路径跟踪精度为主要控制目标,在很大程度上忽略了无人驾驶汽车的乘坐舒适性和控制的拟人程度。为了研究无人驾驶汽车路径跟踪控制算法的拟人程度并提高乘坐舒适性,基于转向几何学、汽车运动学和汽车动力学理论建立实车中常用的4种路径跟踪模型,提出以路径跟踪过程中的最大横向加速度aymax和方向盘转角平方和δw2共同表征路径跟踪模型的拟人程度和横向乘坐舒适性。基于驾驶人实车换道试验数据,建立多项式拟人换道参考路径,搭建CarSim/Simulink联合仿真模型,并对其进行不同车速下的车辆换道试验。研究结果表明:路径跟踪模型的横向循迹偏差均会随着车速的提高而增加,但都能较好实现路径跟踪;带预瞄路径跟踪模型和动力学前馈最优LQR路径跟踪模型拟人程度较好;汽车运动学路径跟踪模型的乘坐舒适性最差,方向盘修正激烈;在100 km·h-1,aymax>0.7 m·s-2,δw2>2.7×103时,拟人程度最差;不带预瞄路径跟踪模型循迹精度最高,且拟人程度最高,乘坐舒适性最好,120 km·h-1时,aymax ≤ 0.5 m·s-2。 相似文献
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为了提高智能汽车的主动安全性,提出3种不同的自动紧急转向避撞跟踪控制方法。首先建立汽车避撞简化模型,对制动、转向及两者相结合的3种不同避撞方式进行对比分析。其次,为深入研究汽车避撞过程中的实际响应,建立包含转向、制动及悬架3个子系统耦合特性的底盘18自由度统一动力学模型,并进行相关试验验证。随后构建智能汽车自动紧急转向避撞控制框架,对五次多项式参考路径和七次多项式参考路径的横摆角速度和横摆角加速度进行对比分析。接着以线性2自由度转向动力学模型为参考对象,对最优控制四轮转向、最优控制前轮转向、前馈与反馈控制相结合的前轮转向3种不同的跟踪控制系统分别进行设计。最后,以汽车底盘18自由度统一动力学模型为研究对象,对上述3种避撞控制系统进行仿真试验对比分析。研究结果表明:与制动避撞相比而言,转向避撞所需的纵向距离有较大降低,随着车速的增加和路面附着系数的越低,效果越明显;七次多项式参考路径比五次多项式参考路径的避撞过渡过程更为平缓,当实际车速与控制器所用车速不一致时,前者避撞性能表现更优;最优四轮转向控制系统在高、低2种不同附着路面都具有较好的避撞效果,最优前轮转向控制系统次之,而前馈与反馈相结合的前轮转向控制系统在低附着路面上则表现出严重的失稳。 相似文献
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S.M. Ei-Demerdash D.A. Crolla 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1996,25(5):369-386
In this work, the preview control problem is considered for fully active and hydro-pneumatic slow-active systems. Based on the quarter car model, linear optimal control theory is used to derive the control laws. The Pade approximation technique is used to represent the preview time resulting from a preview sensor mounted at the front bumper to measure the road irregularities ahead of the front wheels. The results for the slow-active system with preview showed that there is 15% improvement in ride comfort compared to slow-active without preview and 28.5% improvement over passive system at similar root mean square (r.m.s) dynamic tyre load and suspension working space. The performance gains are, however, lower by about 15% than those obtainable with the theoretically ideal, fully active system with preview. The power results for slow active with and without preview showed that a 2kW fixed displacement hydraulic pump is enough for full vehicle requirements. 相似文献
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H. -Z. Li L. Li J. Song L. -Y. Yu 《International Journal of Automotive Technology》2011,12(5):679-686
A new comprehensive driver model is presented for critical maneuvering conditions with more accurate dynamic control performance.
In order to achieve a safe maneuvering mode, a new path planning scheme to maintain stability of the vehicle was designed.
A new steering strategy, considering the errors of vehicle position and yaw angle between the real track and the planned path,
was established to obtain the steering angle. Therefore, the vehicle can be adjusted to accurately follow the desired path
with the driver model, and the stability of the vehicle and the smoothness of the steering angle input were comprehensively
considered. Simulation results were used to validate the control performance in comparison with the optimal preview driver
model proposed by Macadam. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(5):289-326
A mathematical model for the steering control of an automobile is described. The structure of the model derives from linear optimal discrete time preview control theory but it is non-linear. Its parameter values are obtained by heuristic methods, using insight gained from the linear optimal control theory. The driver model is joined to a vehicle dynamics model and the path tracking performance is demonstrated, using moderate manoeuvring and racing speeds. The model is shown to be capable of excellent path following and to be robust against changes in the vehicle dynamics. Application to the simulation of manoeuvres specified by an ideal vehicle path and further development of the model to formalise the derivation of its parameter values and to put it to other uses are discussed. 相似文献