基于无效目标滤除的毫米波雷达农田障碍物检测方法

Method for Millimeter Wave Radar Farm Obstacle Detection Based on Invalid Target Filtering

农田障碍物检测是农机自动驾驶的前提,针对毫米波雷达的农田障碍物检测,本文提出一种无效目标滤除的算法。首先对毫米波雷达所输出的目标信息进行解析并提取农田目标障碍物信息,然后使用无效目标滤除算法对解析后的空目标、伪目标、非威胁数据进行滤除。对雷达数据中目标距离为零的空目标直接滤除;对因雷达工作性能或回波信号不稳定而产生的伪目标通过雷达有效目标生命周期法进行过滤;对超出横向距离阈值和纵向距离阈值的非威胁目标直接滤除。试验结果表明,所提算法在静止状态,平均滤除率达到85%以上。当速度为3 km/h时,未作业状态的平均滤除率为85.24%,旋耕为84.23%;当速度为5 km/h时,未作业为84.22%,旋耕为84.18%;当速度为7 km/h时,未作业为84.19%,旋耕为84.16%。尽管在行驶状态下,随着速度的提升或悬挂旋耕机,滤除率有一定的下降,但本文所提算法在各种状态下的平均滤除率均可达到84%以上。

Farmland obstacle detection is a prerequisite for automatic driving of farm machinery.For farmland obstacle detection based on millimeter wave radar,an algorithm for invalid target filtering was proposed.Firstly,the target information output from the millimeter wave radar was analyzed and the farmland target obstacle information was extracted,and then the empty target,pseudo target and non⁃threat data were filtered out by using the invalid target filtering algorithm.The empty targets with zero target distance in the radar data were directly filtered out;the pseudo targets generated by the radar working performance or unstable echo signal were filtered by the radar effective target life cycle method;the non⁃threat targets exceeding the horizontal distance threshold and vertical distance threshold were directly filtered out.The experimental results showed that the average filtering rate of the proposed algorithm reached more than 85%in the static state.When the speed was 3 km/h,the average filtration rate was 85.24%in the non⁃working state and 84.23%in rotary tillage.When the speed was 5 km/h,84.22%were not operated and 84.18%were rotary tillage.When the speed was 7 km/h,the non⁃operation was 84.19%,and the rotary tillage was 84.16%.The experimental results showed that although the filtering rate was decreased to a certain extent with the increase of speed or hanging rototiller tool in the driving state,the filtering rate of the proposed algorithm could reach more than 84%either in the stationary state or in the driving state.This method can be used to detect obstacles in farmland under complex environment.Under driving conditions,the experimental results showed that the vibration of the tractor had a large influence on the filtering effect.In order to reduce the impact of vibration,a device for millimeter wave radar vibration damping was designed,through the experimental verification,it was showed that the device vibration damping effect was obvious,the average filtering rate in the unoperated state reached more than 84%,which can help to reduce the impact of tractor vibration.