基于线性规划的车辆四轮独立转向控制方法

发布时间：2018-01-16 06:12

本文关键词：基于线性规划的车辆四轮独立转向控制方法　出处：《燕山大学》2016年硕士论文　论文类型：学位论文

【摘要】：四轮独立转向技术能够提高汽车低速的灵活性,高速的操纵稳定性,直接横摆力矩控制技术提高极限工况下的操纵稳定性,上述两项技术已成为研究热点。本文根据样车相关参数建立以四轮转角和横摆力矩为输入,以质心侧偏角和横摆角速度为输出的二自由度五输入车辆模型。根据前轮转向汽车建立以方向盘转角和车速为输入,以质心侧偏角和横摆角速度为输出的理想参考车辆模型。前馈控制器采用四轮独立转向控制和直接横摆力矩控制相结合的控制策略,系统性能指标为车辆四个车轮侧偏角绝对值之和最小,并将含有绝对值的表达式转化为不含绝对值的表达式,根据动力学模型静态表达式、理想质心侧偏角和理想横摆角速度获得前馈控制器约束条件,利用线性规划理论进行控制器求解。仿真验证了在不同工况下,前馈控制器可以优化分配四轮转角,充分利用路面附着条件,增强了车辆的操纵稳定性。但前馈控制器作用下系统有超调量,到达稳态时间较长。设计反馈控制器时,以前馈和反馈共同作用下的四轮侧偏角绝对值之和为最小值,构建包含前馈和反馈控制的性能指标函数,以四轮侧偏角和横摆力矩为输入,建立线性控制系统,建立车辆控制模型和理想跟踪模型,获得反馈控制约束,根据区域极点配置理论配置系统极点,通过仿真分析确定参数值。在不同工况下进行仿真分析,验证了控制器响应速度快,可以抑制超调,优化分配四轮转角。建立坐标转换方程、驾驶员模型和道路函数,组成人-车-路闭环系统。选取不同轨迹和路面,在不同工况下进行道路仿真,仿真表明车辆具有良好的操纵稳定性和跟踪能力,本文设计的控制器控制效果良好。
[Abstract]:The four-wheel independent steering technology can improve the flexibility of low speed, high speed control stability, direct yaw torque control technology to improve the handling stability under the limit conditions. The above two techniques have become a research hotspot. In this paper, four wheel rotation angle and yaw torque are input according to the relevant parameters of the prototype vehicle. A two-degree-of-freedom five-input vehicle model with two degrees of freedom and five input vehicle models with the output of the center of mass side deflection angle and the yaw angular velocity. According to the front wheel steering vehicle, the steering wheel angle and the speed are taken as the input. The ideal reference vehicle model is the side deflection angle of the mass center and the yaw angular velocity. The feedforward controller adopts the control strategy of combining the four-wheel independent steering control with the direct yaw torque control. The system performance index is the smallest sum of the absolute value of the four wheel side deflection angle, and the expression with the absolute value is transformed into the expression without the absolute value, according to the static expression of the dynamic model. The constraint conditions of the feedforward controller are obtained by the ideal centroid side deflection angle and the ideal yaw angular velocity. The linear programming theory is used to solve the controller. The feedforward controller can optimize the allocation of four-wheel rotation angle, make full use of the road surface attachment conditions, and enhance the vehicle handling stability, but the system has overshoot under the action of feedforward controller. When the feedback controller is designed, the sum of the absolute values of the four wheel sideslip angles under the joint action of feedforward and feedback is taken as the minimum value, and the performance index function including feedforward and feedback control is constructed. The linear control system, the vehicle control model and the ideal tracking model are established, and the feedback control constraints are obtained, and the system poles are configured according to the regional pole assignment theory. The simulation results show that the controller is fast in response, can restrain overshoot, optimize the allocation of four-wheel rotation angle, and establish the coordinate transformation equation. The driver model and road function constitute the closed-loop system of man-vehicle-road. Different tracks and roads are selected to simulate the road under different working conditions. The simulation results show that the vehicle has good handling stability and tracking ability. The controller designed in this paper has good control effect.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.4

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