融合2D激光雷达与航向姿态参考系统的采茶机仿形方法研究与试验

Research and Experiment on Profiling Method of Tea Picker Based on Fusion of 2D-LiDAR and Attitude and Heading Reference System

为推动大宗茶机械化采收,提升大宗茶鲜叶采收效率与质量,针对目前仿形采茶机感知传感器易受接触作用力、自然光照或茶蓬面叶片间隙影响,提出了融合2D激光雷达与航向姿态参考系统(Attitude and heading reference system,AHRS)的采茶机割刀仿形距离估计方法,在此基础上,设计并研制精度验证试验台与自动仿形采茶样机,分别开展了室内与田间试验。采茶机采用2D激光雷达测量采茶机割刀仿形距离信息,为提升测距精度与实时性,结合AHRS感知的加速度信息,提出了融合2D激光雷达测距与加速度信息(Fusion of 2D-LiDAR ranging and acceleration,FLRA)的采茶机割刀仿形距离估计算法,并研制了算法精度验证装置和方法,验证了算法有效性。室内试验结果表明,算法处理前仿形距离测距误差均值为36.53 mm,标准差为23.21 mm,算法处理后仿形距离估计误差均值为8.56 mm,标准差为6.31 mm,算法处理后的输出数据延迟更小,提升了仿形距离测距精度与实时性。田间试验表明,鲜叶采收效率达180~210 kg·h^(-1),割刀覆盖蓬面上鲜叶的平均采收率为92.38%,平均芽叶完整率为85.34%,平均杂质率为4.93%,一芽三叶及以下嫩梢占90.72%,满足大宗茶机采技术标准和后续加工工艺要求,与传统超声波感知的自动仿形采茶机相比,提升了大宗茶鲜叶采收效果。

In order to promote the mechanized harvesting of bulk tea and improve the harvesting efficiency and quality of fresh leaves of bulk tea,a fusion 2D-LiDAR and Attitude and heading reference system(AHRS)was proposed in view of the fact that the sensing sensor of the current profiling tea picker is easily affected by contact force,natural light or the gap between the leaves of the tea canopy.Based on the estimation method of profiling distance of cutting knife of tea picker,an accuracy verification test bench and an automatic profiling tea picker were designed and developed,indoor and field experiments were carried out respectively.The tea picker used 2D-LiDAR to measure the profiling distance at first.In order to improve the ranging accuracy and real-time performance,combined with the acceleration sensed by AHRS,a fusion of 2D-LiDAR ranging and acceleration (FLRA) was proposed.The algorithm accuracy verification platform and method were developed to verify the effectiveness of the algorithm.The indoor test results show that the mean value of the ranging error of the profiling distance before the algorithm processing was 36.53 mm,and the standard deviation was 23.21 mm.After the algorithm processing,the mean value of the profiling distance estimation error was 8.56 mm,and the standard deviation was 6.31 mm,which improved the accuracy and real-time performance of profiling distance ranging.Field tests show that the harvesting efficiency reached 180-210 kg·h^(-1).The average picking rate of young shoots on the canopy covered by cutter was92.38%.The integrity rate of bud and leaf was 85.34%and the impurity rate was 4.93%.The young shoots better than one bud and three leaves accounted for 90.72%,which meets the technical standards of bulk tea machine picking and the requirements of subsequent processing technology.Compared with the traditional ultrasonic sensing automatic profiling tea picker,the harvesting effect of bulk tea fresh leaves was improved.