Automatic alignment method of corn harvesterTechnical Field
The invention relates to the field of agricultural automatic machinery, in particular to an automatic alignment method of a corn harvester.
Background
Along with the continuous progress of science and technology, china is increasingly perfected in the development process of agricultural automatic mechanical equipment, and the traditional manual sowing and harvesting modes are gradually changed into the automatic, mechanical and intelligent directions. However, based on the fact that China is used as a traditional agricultural large country, china still has a large progress space in the development of automation and intelligence of agricultural machinery. The automation and the intellectualization of the agricultural machinery are of great significance to the improvement of the crop yield, the reduction of the labor cost and the like.
Corn is the most important member of crops in China, the harvesting period is short, the task is heavy, and the early harvest or the late harvest can influence the yield of the corn, so that the corn harvesting method has certain efficiency. From the different stages of sowing and harvesting, the harvesting machinery is the weakest in the automation link, which becomes the bottleneck of mechanized production of corn. Along with development of scientific technology, a harvester capable of replacing manual corn harvesting appears, but when the traditional corn harvester is used, the traditional corn harvester is used for harvesting along with the wish of an operator, an accurate harvesting path is lacked, so that corn harvesting time is long, and due to lack of path planning, multipath reciprocating motion of the harvester is increased, and harvesting efficiency is reduced.
Disclosure of Invention
In view of the foregoing drawbacks of the prior art, it is an object of the present invention to provide an automatic alignment method for a corn harvester, which solves one or more of the problems of the prior art.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
an automatic alignment method of a corn harvester, comprising the steps of:
The harvester is provided with a detection device.
The cornstalks are dotted by using a dotter to obtain the coordinates of the cornstalks.
And acquiring coordinates of a vehicle control point.
According to the real-time angle variation obtained when the detection device collides and combining the cornstalk coordinates and the vehicle control point coordinates, the calculation of the transverse offset of the cornstalk relative to the vehicle control point is obtained, and the calculation formula of the transverse offset is as follows:
EP=R*(1-cos(α+λθ))
Wherein EP is the lateral offset of the vehicle.
And R is the length of the detection device.
Alpha is the angle change of the angular displacement feedback.
And lambda theta is the angle error compensation quantity obtained through experiments.
And obtaining a northeast coordinate set S of the cornstalks relative to the origin of the vehicle according to the calculated transverse offset and the coordinates of the vehicle control point.
And screening the obtained northeast coordinates set S through a clustering algorithm, and fitting to obtain the trajectory L of the cornstalks.
And calculating the heading offset of the vehicle control point relative to the corn stalk track line L according to the corn stalk track line L, wherein the heading offset is calculated according to the following formula:
θe＝θc-arctan(KL)
Wherein, thetae is the course offset angle.
Θc, the heading angle of the current car body.
KL slope of the corn stalk fitting line.
And setting the obtained transverse offset and the course offset in a transverse course controller to realize automatic control.
Further, the detecting device comprises a lever arm, and the dual-antenna GNSS positioning device is electrically connected to the lever arm.
Further, the real-time angle change amount refers to an included angle formed by the first position and the second position when the lever arm collides with cornstalks.
Further, the northeast coordinate set S is a point set obtained by converting the coordinates of the control points of the vehicle into the northeast coordinates of the origin of the vehicle and then combining the coordinates with the lateral offset, i.e. a point set of the coordinates of the cornstalk relative to the northeast coordinates of the origin of the vehicle.
Further, the clustering algorithm screening MEANS that the central point of the cluster is set as an effective point through a K-MEANS algorithm, and at least one effective point is treated as an array.
Further, the calculation formula of the lateral heading controller is as follows:
J=XTQX+UTPU
And J is an error function of the controller.
XT:Wherein the EP is a lateral deviation, and the EP is a lateral deviation,And thetae is the deviation of the navigation direction,Where t0 is the current time and t1 is the last time.
UT front wheels of the current vehicle are angled.
Compared with the prior art, the invention has the following beneficial technical effects:
By designing a corn harvester automatic alignment method based on a mechanical sensor device and a transverse heading controller. Realize unmanned of maize picker for the harvester can carry out automatic harvesting according to the seeding route of maize, can adjust by oneself according to horizontal skew and navigation skew when the route skew seeding route, alleviateed user's burden when having improved harvesting efficiency greatly.
Drawings
Fig. 1 shows a schematic structural view of mechanical sensor installation of an automatic alignment method of a corn harvester according to an embodiment of the invention.
Fig. 2 shows a mechanical sensor working principle diagram of an automatic alignment method of a corn harvester according to an embodiment of the invention.
Fig. 3 shows a graph of cornstalk cross-bias estimation and actual cross-bias comparison analysis of an automatic alignment method of a corn harvester according to an embodiment of the invention.
Fig. 4 shows a graph of a corn stalk coordinate point clustering experiment result of an automatic alignment method of a corn harvester according to an embodiment of the invention.
Fig. 5 shows a graph of experimental results of cornstalk prediction coordinates of an automatic alignment method of a corn harvester according to an embodiment of the invention.
FIG. 6 shows a schematic diagram of a lateral heading based controller for an automatic alignment method for a corn harvester according to an embodiment of the invention.
The reference numerals in the drawing are 1, a divider, 2, a detection device, 201, a lever arm, 3, a first position, 4 and a second position.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following describes in further detail an automatic line-aligning method of a corn harvester according to the present invention with reference to the accompanying drawings and detailed description. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for the purpose of facilitating and clearly aiding in the description of embodiments of the invention. For a better understanding of the invention with objects, features and advantages, refer to the drawings. It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the invention to the extent that any modifications, changes in the proportions, or adjustments of the sizes of structures, proportions, or otherwise, used in the practice of the invention, are included in the spirit and scope of the invention which is otherwise, without departing from the spirit or essential characteristics thereof.
The automatic alignment method of the corn harvester of the embodiment comprises the following steps:
First, please refer to fig. 1, a detection device 2 is installed on the harvester. Specifically, the detecting device 2 is installed at the center of the crop divider 1 of the harvester, the crop divider 1 of the harvester is used for separating crops into two parts to be cut and cut, the detecting device 2 achieves data acquisition when the crop divider 1 processes crops, and specifically, the detecting device 2 comprises a lever arm 201, and the lever arm 201 is rotatably arranged on the crop divider 1.
And secondly, the user points the cornstalks by holding the high-precision dotter to obtain the coordinates of the cornstalks.
In the third step, please continue to refer to fig. 1, the real-time position information of the vehicle, i.e. the coordinates of the vehicle control point, is obtained by the dual-antenna GNSS positioning, and preferably, the antenna position is electrically connected to the lever arm 201 in this embodiment.
In the fourth step, please continue to refer to fig. 2,3, 5 and 6, a real-time angle change amount can be obtained when the lever arm 201 collides with cornstalks, wherein the real-time angle change amount refers to an included angle formed by the first position 3 and the second position 4 when the lever arm 201 collides with cornstalks. Preferably, the lever arm 201 is rotatably arranged on the detecting device 2. And the horizontal deviation of the cornstalks can be estimated according to the angle variation data, and meanwhile, the actual horizontal deviations of the two lever arms 201 and the harvester are compared and analyzed. The position of the cornstalk is calculated through the obtained real-time angle variation and combining the cornstalk coordinates and the vehicle control point coordinates, a cornstalk prediction coordinate graph is obtained, and then a calculation formula of the transverse offset of the cornstalk relative to the vehicle control point is obtained, wherein the calculation formula is shown in the following formula 1:
EP=R*(1-cos(α+λθ)) (1)
Wherein:
EP-lateral offset of vehicle.
And R is the length of the detection rod.
Alpha is the angle change of the angular displacement feedback.
And lambda theta is the angle error compensation quantity obtained through experiments.
And fifthly, referring to fig. 4 and 6, after the initial origin coordinates of the vehicle are set, the coordinates of the control points of the vehicle and the coordinates of the cornstalks are converted into coordinates of northeast days, and a northeast coordinates set S of the cornstalks relative to the origin of the vehicle is calculated according to the calculated lateral offset. And screening the obtained northeast coordinates set S through a clustering algorithm, and then performing least square fitting to obtain a trajectory L of the cornstalks, wherein the clustering algorithm screening refers to setting a central point of a cluster as an effective point through a K-MEANS algorithm, and treating at least one effective point as an array, and preferably, selecting five effective points as a group to perform least square fitting in the embodiment.
And step six, calculating the heading offset of the vehicle control point relative to the corn stalk track line L by using the obtained corn stalk track line L. The heading offset calculation formula is shown in the following formula 2:
θe＝θc-arctan(KL) (2)
Wherein, thetae is the course offset angle.
Θc —the current car body heading angle obtained by GNSS.
KL slope of the corn stalk fitting line L.
And seventhly, referring to fig. 6, setting the obtained lateral offset and heading offset in the lateral heading controller. The lateral heading controller calculation formula is shown as follows in figure 3:
J=XTQX+UTPU(3)
And J is an error function of the controller.
XT:XT is a parameter matrix, wherein EP is a lateral deviation,
And thetae is the deviation of the navigation direction,Where t0 is the current time and t1 is the last time.
UT front wheels of the current vehicle are angled.
Through writing the formula 3 into the transverse heading controller so as to realize automatic control of the harvester, the harvester can realize automatic angle making according to the position of cornstalks to harvest, the efficiency of harvesting operation is improved, and the labor cost is reduced.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.