RU2600002C1 - Method of tractor curvilinear motion trajectory determining - Google Patents

Abstract

FIELD: agriculture; machine building.

SUBSTANCE: invention relates to agricultural machine building, in particular, to methods of vehicles curvilinear motion trajectory determining, particularly, tractors, and can be used for experimental research of machine-tractor units (MTU) when performing field operations. Method envisages, that during tractor (1) movement along curvilinear trajectory self-adjusting disk (2) draws actual trajectory, corresponding to its kinematic center trajectory. Obtained trajectory is subjected to detailed breakdown at certain intervals (depending on obtained result required accuracy) and it is steeply marked by landmarks. Trajectory polar coordinates (distance from pole (tacheometer installation point) to each of landmarks ρ_i and angles between line are defined using electronic tacheometer with automatic count of angles and distances using laser beam, connecting first of them with tacheometer and subsequent γ_i) and trajectory rectangular coordinates (each of landmark relative to pole X and Y coordinates current values), “passing” by landmarks with reflecting plate. Measurement results are displayed on the screen. Electronic tacheometer is installed with selection of its installation point with minimum distance to landmarks. Kinematic center actual trajectory is obtained according to available coordinates with very high degree of accuracy.

EFFECT: method is aimed at improvement of accuracy of determining of machine-tractor unit trajectory on the field, lower labor input, time for determining coordinates of each point of curve, reduced cost of declared method.

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Description

The invention relates to methods for determining the trajectory of curvilinear movement of vehicles, in particular tractors, and can be used in experimental studies of machine-tractor units (MTA) when performing field work.

The most commonly used indirect method for determining the trajectory of curvilinear motion of the MTA [Kodenko MN, Roslavtsev A.V. A device for determining the trajectory of caterpillar tractors / M.N. Kodenko, A.V. Roslavtsev // Tractors and agricultural machinery. - 1969, No. 10. - S. 13-15], when the rotation angle from the initial position (heading angle) φ with the gyroscopic heading sensor and the actual speed v of the unit’s movement by means of a device connected by a double hinge to the tractor’s skeleton and consisting of track wheel, gearbox and tachogenerator.

To determine the current values of φ and v, it is necessary to divide the waveform section with recording the results of their measurements into n equal intervals. Using the values of φ and v, the current X and Y coordinates of the linear deviations of the given MTA point from the initial position are calculated.

Based on the obtained functions X (t) and Y (t), the tractor trajectory is constructed by approximating the resulting arrays by the least squares method.

The disadvantage of this method is that it uses complex, bulky equipment and insufficiently accurate measuring and recording instruments, as well as the need to set the light beam of the oscilloscope vibrator to zero at each new tractor position. At the same time, the reliability and accuracy of experimental studies are significantly reduced due to measurement errors and manual processing of the results recorded on the oscilloscope tape.

One of the most accurate methods for determining the coordinates of MTA on the ground is the phase method of radio direction finding [Means of motion research MTA / A.V. Roslavtsev [et al.] // Tractors and agricultural machinery. - 1999, No. 3. - S. 26-29] a device containing a phase difference microwave direction finder connected via an analog-to-digital converter to a computer; several microwave generators with power supplies installed on parts of the MTA; a switch providing sequential switching on of generators emitting microwave oscillations through a communication channel in the direction of the differential-phase direction finder. The output voltage of the latter is fed through an analog-to-digital converter to a computer that determines the statistical characteristics and makes up the inter-correlation relationships of the angular and linear movements of the MTA parts.

Thus, this method allows you to directly find the coordinates of the characteristic points of the MTA by measuring the differences of the signals generated in the difference-phase direction finder. The method is characterized by insufficiently high accuracy and reliability of the results, the ability to study any modes of motion of the MTA.

The disadvantage of this method is the high cost of equipment, the acquisition or manufacturing costs of which would not be entirely justified for solving a relatively narrow problem, and the decrease in reliable signal reception with increasing distance from the MTA to the differential-phase direction finder.

Closest to the claimed method of determining the trajectory of the tractor’s curvilinear motion is a method of determining the trajectory of the tractor’s curvilinear motion [application for invention No. 2005109594/28, 04.04.2005], which provides for obtaining the actual curve by copying the movement of the kinematic center on the soil surface and constructing its graphic image in the polar system coordinates by a detailed breakdown of the actual curve and geodetic measurements.

The disadvantage of this method is the low accuracy in constructing the curve due to the arbitrary choice of the installation location of the theodolite, high complexity and time consuming to determine the coordinates of each of its points.

The technical result consists in increasing the accuracy of determining the trajectory of the movement of the machine-tractor unit in the field, reducing the complexity, time spent on determining the coordinates of each point of the curve, reducing the cost of the proposed method.

This is achieved by the fact that as a measuring device for obtaining a graphical image of the curve in polar and rectangular coordinate systems by using a detailed breakdown of the actual curve and geodetic measurements with the display of the measurement results on the display, an automatic total station with the choice of a specific location for its installation is used.

When the tractor moves along a curved path, a self-aligning disc outlines the actual path of its kinematic center. On the resulting trajectory, a detailed breakdown is carried out depending on the required accuracy and is marked with sheer milestones. An electronic total station determines the distance from its installation to the milestones, as well as the angle between adjacent milestones, and the measurement results are displayed. An electronic total station is installed with the choice of a specific installation location so that the distances from the device to the milestones are minimal, a graphical image of the curve is obtained in the polar and rectangular coordinate systems with the display of the measurement results.

As a result of these actions, the accuracy of the obtained trajectory of the movement of the machine and tractor unit in the field is increased, the labor input, the time required to determine the coordinates of each point of the curve, the cost of the proposed method is reduced.

The presence of essential features distinctive from the prototype allows us to recognize the claimed technical solution as new.

The prior art does not reveal technical solutions containing signs that match the distinguishing features of the proposed method, therefore, the claimed method meets the criteria of an inventive step.

The possibility of implementing the claimed invention in industry allows us to recognize it as meeting the criterion of industrial applicability.

The essence of the proposed technical solution is illustrated by an example of a specific design and drawings, which show:

the figure 1 shows a tractor with a self-aligning disk in the kinematic center (middle of the rear wheel);

figure 2 is a diagram of the receipt of the trajectory of the tractor and its measurement in polar coordinates;

figure 3 is a diagram of the receipt of the trajectory of the tractor and its measurement in rectangular coordinates.

The method for determining the trajectory of the curved motion of the tractor is as follows.

When the tractor 1 moves along a curved path, the self-aligning disk 2 outlines the actual path 3 corresponding to the path of its kinematic center. On the obtained trajectory, a detailed breakdown is carried out at certain intervals (depending on the required accuracy of the result obtained) and is marked with vertical marks 4.

An electronic total station 5 with automatic counting of angles and distances determines, using a laser beam, the polar coordinates of the trajectory (the distance from the pole (the installation site of the total station) to each of the poles ρ _i and the angles between the line connecting the first of them with the total station and the subsequent γ _i ) and rectangular the coordinates of the trajectory (the current values of the X and Y coordinates of each of the milestones relative to the pole), "passing" along the milestones with a reflective plate. The measurement results are displayed.

An electronic total station 5 is installed with a choice of a specific location. To reduce the measurement error, a location is chosen so that the distance from the device to the milestones is minimal, which follows from this condition

where m _d is the error of distance measurement; m _β is the error in measuring the angle; ρ is the angle between the milestones; d is the distance from the device to the milestone.

Based on the available coordinates, the actual trajectory of the kinematic center is obtained with a very high degree of accuracy, which is especially important in experimental studies of MTA, since in real conditions they move on a headland with small trajectory radii; in this case, the actual trajectory differs significantly from the nominal one, and even more so from the theoretical one. Obtaining the trajectory by two methods: in polar and rectangular coordinates, allows you to compare the results and evaluate the accuracy of experimental studies.

Based on the obtained trajectory, knowing the geometric parameters of the MTA, it is possible to determine the trajectory of movement of any of its points. And to confirm the results, it is possible to obtain the trajectory of motion of any MTA point experimentally by the same methods as described above.

Claims (1)

A method for determining the trajectory of the tractor’s curvilinear motion, which involves obtaining a real curve by copying the movement of its kinematic center on the soil surface using a self-aligning disk and constructing its graphic image in the polar coordinate system by detailed breakdown of the actual curve and geodetic measurements, characterized in that the graphic image of the curve in polar and rectangular coordinate systems are obtained by a detailed breakdown of the actual curve into milestones and geodetic measurements with the conclusion of the measurement results on the display using an automatic total station with a choice of installation location with a minimum distance to the milestones, passing through them with a reflective plate.

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