Uniform linear array(ULA)radars are widely used in the collision-avoidance radar systems of small unmanned aerial vehicles(UAVs).In practice,a ULA's multi-target direction of arrival(DOA)estimation performance suf...Uniform linear array(ULA)radars are widely used in the collision-avoidance radar systems of small unmanned aerial vehicles(UAVs).In practice,a ULA's multi-target direction of arrival(DOA)estimation performance suffers from significant performance degradation owing to the limited number of physical elements.To improve the underdetermined DOA estimation performance of a ULA radar mounted on a small UAV platform,we propose a nonuniform linear motion sampling underdetermined DOA estimation method.Using the motion of the UAV platform,the echo signal is sampled at different positions.Then,according to the concept of difference co-array,a virtual ULA with multiple array elements and a large aperture is synthesized to increase the degrees of freedom(DOFs).Through position analysis of the original and motion arrays,we propose a nonuniform linear motion sampling method based on ULA for determining the optimal DOFs.Under the condition of no increase in the aperture of the physical array,the proposed method obtains a high DOF with fewer sampling runs and greatly improves the underdetermined DOA estimation performance of ULA.The results of numerical simulations conducted herein verify the superior performance of the proposed method.展开更多
针对高速自动驾驶车辆实时高精度的运动控制问题,提出一种上层为基于路径点Cost的路径点筛选器与基于横纵向轮胎力分析的速度规划器、下层为基于线性时变动力学模型预测的路径跟踪控制器与速度控制器的两层架构,并引入最小均方(Least Me...针对高速自动驾驶车辆实时高精度的运动控制问题,提出一种上层为基于路径点Cost的路径点筛选器与基于横纵向轮胎力分析的速度规划器、下层为基于线性时变动力学模型预测的路径跟踪控制器与速度控制器的两层架构,并引入最小均方(Least Mean Square,LMS)自适应状态估计器提升系统的抗噪性。路径点筛选器提升运算速度并减少筛选过程中的关键信息损失,速度规划器在安全行驶前提下生成最优速度曲线。路径跟踪控制器考虑跟踪偏差软约束,提升跟踪效果。LMS状态估计器基于在线矫正的动力学模型,对横摆角速度与横向速度在线估计。搭建dSPACE-TX2硬件在环仿真环境,在高速公路工况及双移线工况下对比所提出方案与传统运动跟踪控制。半实物仿真结果表明,所提出的运动控制架构提升了抗噪性能与21%的跟踪精度,且满足50 Hz高频控制的要求。展开更多
基金National Natural Science Foundation of China(61973037)National 173 Program Project(2019-JCJQ-ZD-324)。
文摘Uniform linear array(ULA)radars are widely used in the collision-avoidance radar systems of small unmanned aerial vehicles(UAVs).In practice,a ULA's multi-target direction of arrival(DOA)estimation performance suffers from significant performance degradation owing to the limited number of physical elements.To improve the underdetermined DOA estimation performance of a ULA radar mounted on a small UAV platform,we propose a nonuniform linear motion sampling underdetermined DOA estimation method.Using the motion of the UAV platform,the echo signal is sampled at different positions.Then,according to the concept of difference co-array,a virtual ULA with multiple array elements and a large aperture is synthesized to increase the degrees of freedom(DOFs).Through position analysis of the original and motion arrays,we propose a nonuniform linear motion sampling method based on ULA for determining the optimal DOFs.Under the condition of no increase in the aperture of the physical array,the proposed method obtains a high DOF with fewer sampling runs and greatly improves the underdetermined DOA estimation performance of ULA.The results of numerical simulations conducted herein verify the superior performance of the proposed method.
文摘针对高速自动驾驶车辆实时高精度的运动控制问题,提出一种上层为基于路径点Cost的路径点筛选器与基于横纵向轮胎力分析的速度规划器、下层为基于线性时变动力学模型预测的路径跟踪控制器与速度控制器的两层架构,并引入最小均方(Least Mean Square,LMS)自适应状态估计器提升系统的抗噪性。路径点筛选器提升运算速度并减少筛选过程中的关键信息损失,速度规划器在安全行驶前提下生成最优速度曲线。路径跟踪控制器考虑跟踪偏差软约束,提升跟踪效果。LMS状态估计器基于在线矫正的动力学模型,对横摆角速度与横向速度在线估计。搭建dSPACE-TX2硬件在环仿真环境,在高速公路工况及双移线工况下对比所提出方案与传统运动跟踪控制。半实物仿真结果表明,所提出的运动控制架构提升了抗噪性能与21%的跟踪精度,且满足50 Hz高频控制的要求。
