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981.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(9):1153-1170
An important development of the steering systems in general is active steering systems like active front steering and steer-by-wire systems. In this paper the current functional possibilities in application of active steering systems are explored. A new approach and additional functionalities are presented that can be implemented to the active steering systems without additional hardware such as new sensors and electronic control units. Commercial active steering systems are controlling the steering angle depending on the driving situation only. This paper introduce methods for enhancing active steering system functionalities depending not only on the driving situation but also vehicle parameters like vehicle mass, tyre and road condition. In this regard, adaptation of the steering ratio as a function of above mentioned vehicle parameters is presented with examples. With some selected vehicle parameter changes, the reduction of the undesired influences on vehicle dynamics of these parameter changes has been demonstrated theoretically with simulations and with real-time driving measurements. 相似文献
982.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):1575-1596
Steering feel, or steering torque feedback, is widely regarded as an important aspect of the handling quality of a vehicle. Despite this, there is little theoretical understanding of its role. This paper describes an initial attempt to model the role of steering torque feedback arising from lateral tyre forces. The path-following control of a nonlinear vehicle model is implemented using a time-varying model predictive controller. A series of Kalman filters are used to represent the driver's ability to generate estimates of the system states from noisy sensory measurements, including the steering torque. It is found that under constant road friction conditions, the steering torque feedback reduces path-following errors provided the friction is sufficiently high to prevent frequent saturation of the tyres. When the driver model is extended to allow identification of, and adaptation to, a varying friction condition, it is found that the steering torque assists in the accurate identification of the friction condition. The simulation results give insight into the role of steering torque feedback arising from lateral tyre forces. The paper concludes with recommendations for further work. 相似文献
983.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):1193-1213
In this article, an adaptive integrated control algorithm based on active front steering and direct yaw moment control using direct Lyapunov method is proposed. Variation of cornering stiffness is considered through adaptation laws in the algorithm to ensure robustness of the integrated controller. A simple two degrees of freedom (DOF) vehicle model is used to develop the control algorithm. To evaluate the control algorithm developed here, a nonlinear eight-DOF vehicle model along with a combined-slip tyre model and a single-point preview driver model are used. Control commands are executed through correction steering angle on front wheels and braking torque applied on one of the four wheels. Simulation of a double lane change manoeuvre using Matlab®/Simulink is used for evaluation of the control algorithm. Simulation results show that the integrated control algorithm can significantly enhance vehicle stability during emergency evasive manoeuvres on various road conditions ranging from dry asphalt to very slippery packed snow road surfaces. 相似文献
984.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(4):327-338
Via a conventional steering system the driver perceives desired and disturbing effects such as road feedback and resonance effects, respectively. They appear with overlapping frequency spectra within the driver's steering torque. This paper introduces a control algorithm that is suppressing periodic disturbances without affecting useful steering road feedback attributes as well as regular power assistance characteristic. This is realised by an integrated torque actuator within the steering column in conjunction with a conventional Hydraulic-assisted Power Steering (HPS) system. 相似文献
985.
986.
水泥稳定废粘土砖再生集料基层材料性能试验 总被引:1,自引:0,他引:1
为研究掺入废砖块集料后水泥稳定碎石性能的变化规律,在试验中将废砖块集料按20%,40%,60%,80%和100%的比例(质量分数,后同)分别替代粗、细集料配制成2组集料后,用5%水泥拌和制备试件,并测试了混合料的击实特性和试件的抗压、抗折强度、抗压回弹模量、干缩以及抗冻性。结果表明:废砖块集料含量多的混合料最大干密度较小而最佳含水率较大;随着废砖块集料含量的增加,试件抗压强度、劈裂强度、抗压回弹模量、干缩应变和抗冻指数随之下降,而-15℃~40℃温缩应变随之增大;为满足规范对基层强度的最低要求,建议混合料中废砖块集料替代天然粗集料或细集料的替代率分别不要超过70%和90%;另外,在冬季严寒地区,还应该考虑废砖块集料的使用引起的强度损失。 相似文献
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990.
为了较合理地估算刀盘的切削扭矩,对刀盘2种主要刀具即切刀和滚刀的切削扭矩进行研究:首先基于塑性力学中滑移线场,对滚刀和切刀分别建立与其切削机制相对应的塑性力学模型,推导具体的表达式;然后,根据盾构刀具的配置参数及红层掘进参数对刀盘的切削扭矩进行计算,分项求和得到刀盘总扭矩。最后对刀盘计算总扭矩与施工实测总扭矩相比较,并分析理论计算模型存在的误差原因。研究结果表明:滚刀在红层中受均匀磨损,磨损量小,刀盘扭矩的实际装备系数为3.2,有一定的富余。研究结果可为盾构刀盘的设计、施工提供参考。 相似文献