CN-121979023-A - Cooperative grain unloading control method for combine harvester-grain transporting vehicle

CN121979023ACN 121979023 ACN121979023 ACN 121979023ACN-121979023-A

Abstract

A cooperative grain unloading control method for a combine harvester-grain transporting vehicle adopts RTK-GNSS, depth camera and millimeter wave radar to respectively acquire relative position information of the combine harvester and the grain transporting vehicle, carries out multi-sensor information fusion on the acquired information to acquire more accurate relative pose information, adjusts the motion state of the grain transporting vehicle according to the acquired pose information, provides accurate motion adjustment parameters for grain unloading operation, ensures that the combine harvester and the grain transporting vehicle have a certain safe driving distance in the cooperative grain unloading operation, can realize uniform grain loading in a grain tank of the grain transporting vehicle without overflowing to overcome the influence of noise, signal loss and the like existing in a complex farmland environment of a single sensor on the system, and simultaneously ensures that the acquired information is a real-time dynamic parameter and the accurate butt joint and real-time adjustment of the positions of a grain unloading port and the grain tank.

Inventors

LIU WEIXIANG
JI JIANGTAO
Zhao kaixuan
SUN JINGWEI
Du Shucan
LIU QIHANG
WANG CHAOYANG
WU YUANZE
WANG HAIYUAN

Assignees

河南科技大学

Dates

Publication Date: 20260505
Application Date: 20251226

Claims (4)

1. A cooperative grain unloading control method for a combine-grain carrier, wherein the combine and the grain carrier run in the same direction, and grain is unloaded from the combine to a grain tank of the grain carrier, the method comprising the steps of: step 1, defining the length direction of the combine harvester and the grain carrier as the longitudinal direction and the width direction as the transverse direction, establishing a coordinate system on the same plane containing the combine harvester and the grain carrier, taking the heading angle 0 degree direction as a coordinate system x-axis extending along the longitudinal direction and taking the heading angle 90 degree direction as a coordinate system y-axis extending along the transverse direction; Selecting a point P m (x m ,y m ) on the central line of the combine along the longitudinal direction as a positioning point of the combine; A point P n (x n ,y n ) is selected on the central line of the grain transport vehicle along the longitudinal direction and is used as a positioning point of the grain transport vehicle, and P n is positioned at the head of the grain transport vehicle; Selecting a plurality of points P i (i=1, 2, 3.) on the longitudinal centerline of the grain cart as grain unloading points, P i being located in the grain bin of the grain cart, adjacent grain unloading points P i being located a distance d 0 ,P n from a first grain unloading point P 1 closest to the head of the grain cart by a distance d 1 ; step 2, obtaining RTK-GNSS control information 2.1, Installing RTK-GNSS positioning modules on the combine harvester and the grain carrier, and collecting geometrical position relations of working states of vehicle parts of the combine harvester and the grain carrier in real time, wherein the geometrical position relations comprise longitude and latitude, speed and course angle; 2.2, defining a projection point of an outlet of a grain discharging cylinder of the combine harvester on a coordinate system plane as P mn , and obtaining an included angle theta 1 between the connecting line direction and the running direction of the distances d m 、P mn and P m of the P mn and the locating point P m of the combine harvester, an included angle alpha m between the running direction of the combine harvester and the x axis of the coordinate system and an included angle alpha n between the running direction of the grain transporting vehicle and the x axis of the coordinate system according to the geometric position relation of the working state of the vehicle part; 2.3, calculating the coordinates of P mn as follows: (1); 2.4, the distance between the grain conveying vehicle positioning point P n and the grain unloading point P i is as follows: (2); the coordinates of the grain unloading point P i are calculated as follows: (3); 2.5, according to the coordinates of P mn and the coordinates of P i , calculating to obtain the distance between P mn and P i as follows: (4); Calculating to obtain an included angle theta 2 between the connecting line direction of the P mn and the P i and the running direction of the grain carrier; (5); 2.6, the longitudinal distance d n1' and the transverse distance d n2' of P mn and P i obtained according to the formulas (4) and (5) are respectively: (6); The pose detection relative heading angle delta alpha 1 of the combine harvester and the grain carrier is as follows: (7); 2.7, acquiring real-time coordinate values of P m and P n in the running process according to the RTK-GNSS positioning module, and further acquiring real-time dynamic transverse and longitudinal direction and course deviation in the grain unloading operation process of the combine harvester and the grain carrier; Step 3, obtaining millimeter wave radar control information A millimeter wave radar is installed on one side of the grain carrier, facing the combine harvester, and two reflectors are installed on the side of the combine harvester and at a distance L between the height positions of the millimeter wave radar, so that a first stable reflection point and a second stable reflection point are obtained, and the output of the millimeter wave radar is (r 1 ,φ 1 ）、（r 2 ,φ 2 ) for the two stable reflection points; The distance d mn and the relative heading delta alpha 2 of the first stable reflection point relative to the grain carrier are respectively obtained through the millimeter wave mine and the reflector and are as follows: (8); the transverse distance d n2'' between the combine harvester and the grain conveying vehicle is as follows: (9); In the formula (9), d m0 is the distance between the longitudinal center line of the grain carrier and the installation side surface of the millimeter wave radar, d n0 is the distance between the first stable reflection point and P m , and theta 3 is the included angle between the connecting line of the first stable reflection point and P m and the running direction of the combine harvester; step 4, obtaining depth camera control information 4.1, Arranging a front depth camera and a rear depth camera in a grain tank of the grain transportation vehicle, acquiring RGB images and depth images of grains in the rear half part of the grain tank through the front camera, acquiring the RGB images and the depth images of the grains in the front half part of the grain tank through the rear camera, fusing the RGB images and the depth images, and generating a front camera three-dimensional point cloud and a rear camera three-dimensional point cloud; 4.2, setting a direct filtering threshold, firstly carrying out direct filtering on point cloud data, and then carrying out voxel downsampling filtering to filter noise points and invalid points; Firstly carrying out coarse registration on the denoised point cloud data, and then carrying out fine registration by utilizing the plane characteristic constraint of the grain bin; 4.3, merging the registered front camera three-dimensional point cloud and the registered rear camera three-dimensional point cloud to obtain a global carriage point cloud, performing voxel grid de-duplication on the global carriage point cloud, and removing repeated points in an overlapping area; 4.4, extracting edge information of grains and grain boxes by adopting a plane difference method on global carriage point cloud data after weight removal, extracting the height difference between the grains and the top of the grain boxes by adopting a RANSAC algorithm on the obtained edge information, and longitudinally dividing the grain boxes into a plurality of full-load areas and non-full areas according to a set height difference threshold value; 4.5, setting an area which is not full and is used for unloading grains next as a target position of an outlet of the grain unloading cylinder, and combining the existing positions of the combine harvester and the grain conveying vehicle to obtain a longitudinal distance d n1'' which is required to be moved relatively when the combine harvester and the grain conveying vehicle reach the target position; step 5, multi-sensor information fusion is carried out by adopting EKF fusion algorithm 5.1, Combining the longitudinal distance d n1' , the transverse distance d n2' , the pose detection relative heading angle Δα 1 obtained in step 2, the radar detection relative heading angle Δα 2 obtained in step 3, the transverse distance d n2'' , and the longitudinal distance d n1'' obtained in step 4 into multi-sensor information z k , expressed as: (10); in the formula (10): (11); In the formula (11), R is observation noise; 5.2, defining the relative states of the combine harvester and the grain carrier as follows: (12); in the formula (12), d n1 is the relative longitudinal distance between the combine and the grain carrier, d n2 is the relative transverse distance between the combine and the grain carrier, and delta alpha is the course angle deviation between the combine and the grain carrier; 5.3, the state transition equation is: (13); in the formula (13), Q is process noise; 5.4, predicting the current state according to the optimal state estimation at the previous moment and introducing process noise: (14); (15); In the formula (15), P is a covariance matrix; 5.5, calculating residual errors: (16); calculating residual covariance: (17); calculating Kalman gain: (18); Obtaining a fusion result by updating the state : (19); By fusing the results Obtaining a fused longitudinal distance d n1 , a fused transverse distance d n2 and a course angle deviation delta alpha, and updating covariance: (20); normalizing the fused course angle deviation: (21); And 6, controlling the cooperative grain unloading operation according to the longitudinal distance d n1 , the transverse distance d n2 and the course angle deviation delta alpha obtained in the step 5, so that d n1 、d n2 and delta alpha are close to 0.
2. A cooperative grain unloading control method for a combine-grain carrier as defined in claim 1, wherein the combine transmits pose information to the grain carrier through WiFi.
3. The method for collaborative grain unloading control of a combine-grain cart of claim 1, wherein the front camera and the rear camera are connected by a synchronization cable to achieve frame synchronization.
4. The method for cooperative grain unloading control of a combine-grain wagon according to claim 1, wherein the course angle deviation is normalized according to the formula (21) before the fusing in the step 5.

Description

Cooperative grain unloading control method for combine harvester-grain transporting vehicle Technical Field The invention relates to the technical field of cooperative grain unloading of a harvester and a grain conveying vehicle, in particular to a cooperative grain unloading control method for a combine harvester-grain conveying vehicle. Background The agricultural machinery multi-machine collaborative operation research is used as one of the hot spots of the research in the field of the current intelligent agricultural equipment, and has important research significance and practical value in the aspects of accelerating the task execution speed of the cluster, reducing the system consumption, improving the utilization rate and the operation efficiency of the agricultural machinery, improving the operation quality of the agricultural machinery and the like. The harvesting operation is one of important links in the agricultural production process, the characteristics of strong agricultural time and strict operation window period of the agricultural production are more outstanding, and the cooperative grain unloading operation system can meet the operation state of harvesting and unloading grains when the grain tank of the combine harvester is full, so that the harvesting operation efficiency is improved. The research on the multi-machine collaborative operation technology at home and abroad is concentrated in the fields of robots, unmanned aerial vehicles and the like, the research on the collaborative operation technology in the harvesting operation process in the agricultural field is relatively less, the research on the collaborative control strategy is mostly developed, the research on the whole grain unloading operation system is also mostly a fixed-point grain unloading system, the acquisition means of the relative pose information between two vehicles in the collaborative grain unloading operation process is relatively single, and the two-vehicle collaborative operation requirement of the combine harvester-grain transport vehicle is difficult to meet. Disclosure of Invention The invention aims to provide a cooperative grain unloading control method for a combine harvester-grain carrier, which is used for obtaining accurate relative pose information and realizing the adjustment of motion parameters in the grain unloading operation process. The invention aims to solve the technical problems, and adopts the technical scheme that the cooperative grain unloading control method for the combine harvester-grain carrier comprises the following steps of: step 1, defining the length direction of the combine harvester and the grain carrier as the longitudinal direction and the width direction as the transverse direction, establishing a coordinate system on the same plane containing the combine harvester and the grain carrier, taking the heading angle 0 degree direction as a coordinate system x-axis extending along the longitudinal direction and taking the heading angle 90 degree direction as a coordinate system y-axis extending along the transverse direction; Selecting a point P m(xm,ym) on the central line of the combine along the longitudinal direction as a positioning point of the combine; A point P n(xn,yn) is selected on the central line of the grain transport vehicle along the longitudinal direction and is used as a positioning point of the grain transport vehicle, and P n is positioned at the head of the grain transport vehicle; Selecting a plurality of points P i (i=1, 2, 3.) on the longitudinal centerline of the grain cart as grain unloading points, P i being located in the grain bin of the grain cart, adjacent grain unloading points P i being located a distance d 0,Pn from a first grain unloading point P 1 closest to the head of the grain cart by a distance d 1; step 2, obtaining RTK-GNSS control information 2.1, Installing RTK-GNSS positioning modules on the combine harvester and the grain carrier, and collecting geometrical position relations of working states of vehicle parts of the combine harvester and the grain carrier in real time, wherein the geometrical position relations comprise longitude and latitude, speed and course angle; 2.2, defining a projection point of an outlet of a grain discharging cylinder of the combine harvester on a coordinate system plane as P mn, and obtaining an included angle theta 1 between the connecting line direction and the running direction of the distances d m、Pmn and P m of the P mn and the locating point P m of the combine harvester, an included angle alpha m between the running direction of the combine harvester and the x axis of the coordinate system and an included angle alpha n between the running direction of the grain transporting vehicle and the x axis of the coordinate system according to the geometric position relation of the working state of the vehicle part; 2.3, calculating the coordinates of P mn as follows: (1); 2.4, the distance between the grain co