Input–Output Decoupling Control by Measurement Feedback in Four-Wheel-Steering Vehicles
Input–Output Decoupling Control by Measurement Feedback in Four-Wheel-Steering Vehicles
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DOI：
10.1109/tcst.2008.2004441
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发表时间：
2009-06
影响因子：
4.8
通讯作者：
R. Marino;F. Cinili
中科院分区：
文献类型：
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作者：
R. Marino;F. Cinili
基于四轮转向车辆的单轨线性化模型，设计了二阶动态解耦控制器。横摆角速度和横向速度是要解耦的输出，而后转向角和相对于驾驶员命令的附加转向角是控制输入。它示出的横向速度动态和横摆角速度动态可以通过反馈纵向速度，横摆角速度和横向加速度测量解耦，而传感器干扰对横摆角速度的影响被衰减。不需要横向速度测量或观察员。横摆角速度控制的动态是独立于横向速度，并描述了一个三阶输入输出模型，取决于驾驶员方向盘命令和传感器干扰;横向速度动态是自主的，并趋于指数为零与车辆相关的时间常数，而横向加速度往往是成比例的横摆角速度。对单轨模型的非线性分析表明，随着临界驱动阶跃输入的增加，不受控系统的不稳定平衡点被抑制，新的稳定平衡点产生，稳定区域扩大。在非线性三阶单轨道模型和CarSim提供的高阶模型上对典型机动和干扰进行了仿真，结果表明，该系统对未建模动态、车辆参数不确定性和传感器干扰具有鲁棒性;此外，还证实了显著的动态解耦、更大的带宽、超调抑制和即使在高速下也能提高机动性。
The well-known single-track linearized model for four-wheel-steering vehicle dynamics is used to design a second-order dynamic decoupling controller. Yaw rate and lateral speed are the outputs to be decoupled, while the rear steering angle and an additive steering angle with respect to the driver command are the control inputs. It is shown that the lateral speed dynamics and the yaw rate dynamics can be decoupled by feeding back longitudinal speed, yaw rate, and lateral acceleration measurements, while the effect of sensor disturbances on yaw rate is attenuated. Lateral speed measurements or observers are not required. The yaw rate controlled dynamics are independent from lateral speed and are described by a third-order input-output model, depending on the driver steering wheel command and sensor disturbances; the lateral speed dynamics are autonomous and tend exponentially to zero with a vehicle-dependent time constant while the lateral acceleration tends to be proportional to the yaw rate. The nonlinear analysis on a single-track model shows the suppression of the unstable equilibrium points of the uncontrolled system, the generation of new stable equilibrium points as the critical driver step input increases, and the enlargement of the stability regions. Simulations of typical maneuvers and disturbances on a nonlinear third-order single-track model and on a higher order model provided by CarSim show robustness with respect to unmodeled dynamics, vehicle parameter uncertainty, and sensor disturbances; moreover, significant dynamic decoupling, larger bandwidth, overshoot suppression, and improved maneuverability even at high speed are confirmed.