Research On Seeding Depth Detection And Control System Based On Multi-sensor Data Fusion

Precision sowing is a sowing technique that requires precise sowing volume,spacing and depth.Precision sowing ensures that the seed in the field is consistent in spacing and that the seed is at the same depth in the soil,which in turn allows the seed to grow and develop at a consistent rate and receive sufficient nutrients.The consistency of seed sowing depth has an important influence on seed emergence and crop yield,and the consistency of the precision seeder’s sowing depth will determine the quality of the sowing.Therefore,the research of sowing depth control technology is of great significance for precision sowing.In the field of sowing depth control,passive profiling with spring as the control mechanism has gradually failed to meet the needs of sowing operations in modern agriculture at high speed,therefore,active profiling mechanism is needed to improve the stability of sowing depth.This paper mainly combines the current domestic and international research basis,and conducts research on the problems of poor stability of sowing depth detection data,complex structure of active control device and imprecise action in the current active control system of sowing depth,etc.The specific research contents are as follows:(1)The seeding depth detection and control system is designed as a whole.The system is divided into two parts: detection and control.The detection part uses laser sensor and ultrasonic sensor as the sowing depth detection device.The control part adopts servo-electric cylinder as the active control mechanism,which is simpler in terms of pipeline arrangement than airbag and hydraulic control system and is less prone to failure during operation,so it is more suitable to choose servo-electric cylinder as the sowing depth control system.The sowing depth detection and control system uses a microcontroller as the main control chip to communicate with the sensor using the 485-communication protocol,and an LCD screen as the display module to show the current system work information.The system as a whole is designed with hardware circuits and software processes.(2)In order to solve the problem of large fluctuation of sensor data in field operation,this paper adopts multi-sensor data fusion algorithm to enhance data stability and accuracy.Multi-sensor data fusion algorithm consists of two parts: data preprocessing and data fusion.The data pre-processing method is compared with the adaptive Kalman filter for filtering,which is adaptive to noise and more resistant to interference than other algorithms.The data fusion algorithm uses a weighted averaging algorithm for data fusion,which is simple and intuitive,with a low computing burden on the processor and a fast response time.The mean square error of the multi-sensor data fusion is 0.0033 and the servo-cylinder control algorithm uses a threshold control algorithm,which can act according to whether the current sowing depth variation range exceeds the threshold value.The maximum error of the servo-cylinder action test is 0.08 mm.(3)Threshold value control algorithm is used for control in the servo electric cylinder control algorithm.The threshold control algorithm can perform corresponding actions according to whether the current sowing depth variation range exceeds the threshold value,and the movement burden on the servo electric cylinder is small.At the same time,compared with PID and other controls The algorithm does not need to be modeled,which greatly reduces the computational burden of the processor.The maximum average error of the servo electric cylinder action test is 0.08 mm.(4)In order to test the response time of the system and its working performance in the field operation,the system response test and field test were carried out on the seeder depth detection and control system.The field test shows that the sowing depth under active profiling control is more stable when the tractor operating speed changes.Compared with passive profiling,active profiling can obtain better control effect,and the sowing depth is qualified under the operating speed of 5-10km/h The rate can still reach more than 90%.Among them,the average sowing depth variation coefficient of passive profiling is 9.5%,and the average sowing depth variation coefficient of active profiling is 6.1%.The average sowing depth variation coefficient of active profiling is 3.4% less than that of passive profiling.Therefore,the sowing depth detection and control system in this paper can meet the needs of the field operation.