Unmanned turning method for agricultural machinery
Technical Field
The invention relates to the technical field of automatic driving of agricultural machinery, in particular to an unmanned turning method of the agricultural machinery.
Background
The automatic driving automobile relies on cooperation of artificial intelligence, visual computing, radar, monitoring device and global positioning system, so that the computer can automatically and safely operate the motor vehicle without any active operation of human beings.
With the development and popularization of agricultural automation, agricultural automatic driving is gradually promoted, and the field of agricultural automatic driving often relates to turning path planning when the land is automatically turned around.
There are generally three schemes, dubins curve path planning:
no reverse path planning (as shown in fig. 4), longer paths, larger space in the ground, and discontinuous curvature are required.
Reeds-shepp curve path planning (as shown in FIG. 5): backing path planning is supported, the path is shorter, but is not optimal or optimal, and the curvature is discontinuous.
Intersection curve path planning (as shown in fig. 6) with the same arc radius: backing path planning is supported, the optimal path, but the curvature is discontinuous.
Disclosure of Invention
The invention aims to provide an unmanned turning method of an agricultural machine, which aims to solve the problems of longer path, larger required land space, discontinuous curvature and discontinuous curvature in the prior art.
In order to achieve the above purpose, the present invention provides the following technical solutions: an unmanned turning method of an agricultural machine comprises the following specific steps:
the unmanned turning method of the agricultural machinery is divided into five operation sections:
s1: advancing operation straight line segment 1: straight running, wherein the running direction is parallel to the road direction;
s2: advancing arc section 2: at the step S1, the tail end enters this stage, the advancing arc segment 2 is in an arc shape moving to the left and the front, and the advancing arc segment 2 is divided into three stages: the first stage and the third stage use Euler spiral formulas to calculate the running direction and the running distance, the second stage is to keep running with a fixed radius, and the head end and the tail end of the second stage are respectively connected with the tail end of the first stage and the head end of the third stage;
s3: reversing straight line segment 3: reversing along a reversing straight line section 3 after the forward arc section 2 is finished, wherein the reversing straight line section 3 is perpendicular to the forward operation straight line section 1;
s4: arc segment 4: the circular arc section 4 and the forward circular arc section 2 are symmetrical about the perpendicular bisector of the reversing straight line section 3, and the reversing straight line section 3 is the starting point of the circular arc section 4;
s5: operation straight line segment 5: the end of the arc section 4 is the starting point of the working straight-line section 5, and the working straight-line section 5 and the advancing working straight-line section 1 are parallel and opposite in direction.
Preferably, the coordinate points K (x k ,y k ) The Euler spiral formula is adopted for definition, and the method specifically comprises the following steps:
wherein c is the rate of change of curvature, s is the arc length, a 2 Is the tangential angle.
Compared with the prior art, the invention has the beneficial effects that:
the agricultural machinery is unmanned, needs to carry out automatic turning control at the ground, and the circular arc section of this scheme uses Euler spiral to plan, can guarantee the curvature continuity of circular arc section route to make the agricultural machinery can strictly reasonable follow the route and carry out automatic turning control.
The automatic turning path of the agricultural machine adopts a cross type, the arc section adopts a sectional type, the front section and the rear section are planned by using Euler screws, the middle section is planned by using the minimum turning radius of the vehicle, so that the minimum space of the ground is ensured, the curvature continuity is ensured, the agricultural machine turning control can be performed by strictly following the path, and the agricultural machine is prevented from deviating from the planned path.
Drawings
FIG. 1 is a schematic illustration of a travel path of the present invention;
FIG. 2 is a schematic diagram of the step S2 of the present invention in three steps;
FIG. 3 is a calculated scribe line diagram of the present invention;
FIG. 4 is a prior art Dubin curve path planning diagram;
FIG. 5 is a prior art Reeds-shepp curve path planning diagram;
fig. 6 is a prior art cross curve path planning diagram with the same radius of the arc.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the present invention and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.
Examples:
referring to fig. 1-6, the present invention provides a technical solution: an unmanned turning method of an agricultural machine comprises the following specific steps:
the unmanned turning method of the agricultural machinery is divided into five operation sections:
s1: advancing operation straight line segment 1: straight running, wherein the running direction is parallel to the road direction;
s2: advancing arc section 2: at the step S1, the tail end enters this stage, the advancing arc segment 2 is in an arc shape moving to the left and the front, and the advancing arc segment 2 is divided into three stages: the first stage and the third stage use Euler spiral formulas to calculate the running direction and the running distance, the second stage is to keep running with a fixed radius, and the head end and the tail end of the second stage are respectively connected with the tail end of the first stage and the head end of the third stage;
s3: reversing straight line segment 3: reversing along a reversing straight line section 3 after the forward arc section 2 is finished, wherein the reversing straight line section 3 is perpendicular to the forward operation straight line section 1;
s4: arc segment 4: the circular arc section 4 and the forward circular arc section 2 are symmetrical about the perpendicular bisector of the reversing straight line section 3, and the reversing straight line section 3 is the starting point of the circular arc section 4;
s5: operation straight line segment 5: the end of the arc section 4 is the starting point of the working straight-line section 5, and the working straight-line section 5 and the advancing working straight-line section 1 are parallel and opposite in direction.
Preferably, the coordinate points K (x k ,y k ) The Euler spiral formula is adopted for definition, and the method specifically comprises the following steps:
wherein c is the rate of change of curvature, s is the arc length, a 2 Is the tangential angle.
As shown in fig. 3, included angles EF and AB are equal to included angles HI and CD, the curvatures of the a point and the b point are the same, the track of the arc sections 6 and 8 can be calculated according to the euler spiral curve formula, and the arc section 7 can keep the curvatures of the a point and the b point to make a circle.
The agricultural machinery is unmanned, automatic turning control is needed to be carried out on the ground, the minimization of ground space can be met by using the cross-type path planning supporting the reversing path, but if the arc section is planned by directly using a fixed turning radius, the agricultural machinery needs to stop first and turn around in situ, the abrasion of tires is very large, if the tires are not stopped and directly followed, the agricultural machinery is automatically controlled to deviate from the planned path due to the discontinuous curvature of the arc path, unpredictable results are caused, the arc section is planned by using the Euler spiral, and the continuity of the curvature of the arc section path can be ensured, so that the agricultural machinery can strictly and reasonably follow the path to carry out automatic turning control.
The automatic turning path of the agricultural machine adopts a cross type, the arc section adopts a sectional type, the front section and the rear section are planned by using Euler screws, the middle section is planned by using the minimum turning radius of the vehicle, so that the minimum space of the ground is ensured, the curvature continuity is ensured, the agricultural machine turning control can be performed by strictly following the path, and the agricultural machine is prevented from deviating from the planned path.
While the fundamental and principal features of the invention and advantages of the invention have been shown and described, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but may be embodied in other specific forms without departing from the spirit or essential characteristics thereof; the present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.