CN105372078A - Roller tractor turning control method and device - Google Patents

Abstract

The invention provides a roller tractor turning control method and device. The method comprises the steps that the point coordinates of multiple points on a track circle formed by moving of a roller tractor for at least one circle at a constant speed are acquired, and the track circle is formed in a way that the steering wheel of the roller tractor is rotated to a preset position and then maintained unchanged in moving; fitting calculation of the point coordinates of multiple points is performed by utilizing a circle fitting method, and the moving track circle radius R<0> of the roller tractor is determined; moving turning radius R=R<0>+L<tw>/2 of the roller tractor is determined according to front wheel distance L<tw> of the front wheels of both sides of the roller tractor and the track circle radius R<0>; and turning control of the roller tractor is performed according to the turning radius R=R<0>+L<tw>/2. According to the roller tractor turning control method and device, the problems in the prior art that measurement technological means are poor and measurement precision is low can be effectively overcome, turning control precision of the roller tractor can be guaranteed, and enhancement of working efficiency of the roller tractor is facilitated.

Description

The Servo Control method of wheeled tractor and device

Technical field

The present invention relates to wheeled tractor technical field, be specifically related to a kind of Servo Control method and device of wheeled tractor.

Background technology

Wheeled tractor is a class of tractor, be suitable for barton to wear wide cut farm implements and carry out farmland operation, and with regard to wheeled tractor, radius of turn refers to when steering wheel forwards extreme position to, during with minimum stabilizing speed Turning travel, the trace radius that rolls across on supporting plane of center of outside deflecting roller, is radius of turn.For wheeled tractor, radius of turn index not only characterizes steering behaviour, more has influence on the cornering mode adopted in Field-working Tractor-implement process; In the Tractor Products parameter that agricultural machinery manufacturer provides abroad, radius of turn is one of canonical parameter of steering.

In prior art, define the test method of automobile turning measuring diameter, it is particular by above front foreign steamer and rear interior tire tread center, at car body from solstics, turning center and closest approach vertical ground direction, installs and travels track display device; Automobile is at low speed, and bearing circle forwards extreme position to, keeps motionless, starts display device, make each measuring point demonstrate closed movement locus on the ground respectively after the speed of a motor vehicle is stable; The locus circle diameter that each measuring point formed on the ground is measured with steel tape; At present, there is no the method for wheeled tractor radius of turn and device.

And if adopt the radius of turn of method determination wheeled tractor of the prior art and Servo Control carried out to wheeled tractor, inventor finds to there is following problem: adopt the display precision as driving trace display device such as water spray pins directly to affect the measuring accuracy of turning diameter, be difficult to determine two measuring point lines on the ground measured by steel tape, thus should the measuring accuracy of turning diameter, the asymmetric steering cylinder of the many employings of domestic wheeled tractor, cause the radius of turn of the left and right sides different, but manufacturer seldom provide left and right radius of turn index parameter; The problems referred to above all can affect final degree of accuracy of wheeled tractor being carried out to Servo Control.

Summary of the invention

The invention provides a kind of Servo Control method and device of wheeled tractor, realize the measurement result exporting wheeled tractor radius of turn quickly and accurately, effectively solve the problems such as the technological means existed in radius of turn assay method of the prior art is coarse and crude, measuring accuracy is low, and then effectively raise the control accuracy of the turning to wheeled tractor.

The one side that the present invention is is a kind of Servo Control method in order to provide wheeled tractor, comprising:

Obtain point coordinate that wheeled tractor at the uniform velocity travels several points on locus circle that at least one circumference formed, described locus circle is rotated to predeterminated position by the bearing circle of described wheeled tractor to keep motionless rear traveling to be formed;

Utilize the point coordinate of circle approximating method to several points described to carry out the Fitting Calculation, determine the trace radius R that described wheeled tractor travels ₀;

According to the front-wheel spacing L of described wheeled tractor both sides front-wheel _twwith described trace radius R ₀, determine the front foreign steamer radius of turn that described wheeled tractor travels

According to described radius of turn servo Control is carried out to described wheeled tractor.

The Servo Control method of wheeled tractor as above, the bearing circle that described predeterminated position is described wheeled tractor turn clockwise extreme position extremely, or be rotated counterclockwise extreme position extremely;

Accordingly, the radius of turn of the locus circle travelled according to described wheeled tractor determines the minimal curve radius of described wheeled tractor.

The Servo Control method of wheeled tractor as above, described circle approximating method is least square method, carries out the Fitting Calculation, determine the trace radius R that described wheeled tractor travels by the point coordinate of least square method to several points described ₀, specifically comprise:

According to the point coordinate (X of several points described _i, Y _i) i ∈ (1,2...N), obtain following parameter:

A＝ΣX _i，

B＝ΣY _i，

C＝Σ(X _i+Y _i)，

D＝N·ΣX _i ²-(ΣX _i) ²，

E＝N·ΣY _i ²-(ΣY _i) ²，

F＝N·ΣX _i·Y _i-ΣX _i·ΣY _i，

G＝N·ΣX _i ³+N·ΣX _iY _i ²-Σ(X _i ²+Y _i ²)·ΣX _i，

H＝N·ΣY _i ³+N·ΣX _i ²Y _i-Σ(X _i ²+Y _i ²)·ΣY _i；

According to x ²+ y ²+ ax+by+c=0 determines intermediate variable a, b and c, wherein x ∈ X _i, y ∈ Y _i:

$a=\frac{F\&CenterDot;H-E\&CenterDot;G}{D\&CenterDot;E-F^2},b=\frac{D\&CenterDot;H-F\&CenterDot;G}{F^2-D\&CenterDot;E},c=-\frac{C+a\&CenterDot;A+b\&CenterDot;B}{N},$ Wherein N is positive integer;

According to determine described trace radius.

The Servo Control method of wheeled tractor as above, described determine the radius of turn that described wheeled tractor travels after, also comprise:

Obtain the distance between axles L of the left side of described wheeled tractor or the front-wheel wheel shaft on right side and rear axle _b, and according to described distance between axles L _bwith the angular relationship of described radius of turn R obtain the front wheel angle that described wheeled tractor travels

The Servo Control method of wheeled tractor as above, also comprises:

Obtain the installation predetermined angle δ that rotary angle transmitter is arranged on described wheeled tractor front-wheel _c, 0≤δ _c≤ δ _max;

According to the described front-wheel spacing L taken turns in front side _twwith the angular relationship of described radius of turn R ${\mathrm{tan\&delta;}}_n=\frac{L_b}{R-\frac{L_{tw}}{2}},$ Obtain the corner of wheel in described front side ${\mathrm{\&delta;}}_n=arctan\frac{L_b}{R-\frac{L_{tw}}{2}};$

According to the described front-wheel spacing L of front side foreign steamer _twwith the angular relationship of described radius of turn R ${\mathrm{tan\&delta;}}_w=\frac{L_b}{R+\frac{L_{tw}}{2}},$ Obtain the corner of described front side foreign steamer ${\mathrm{\&delta;}}_w=arctan\frac{L_b}{R+\frac{L_{tw}}{2}};$

If described rotary angle transmitter is installed in described front side on wheel, then according to the corner of taking turns in described front side with described installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of described rotary angle transmitter _c-δ _n;

If described rotary angle transmitter is installed on the foreign steamer of described front side, according to the corner of described front side foreign steamer with described installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of described rotary angle transmitter _c-δ _w;

According to the installation deviation angle of described rotary angle transmitter, determine the setting angle of described rotary angle transmitter.

The another aspect that the present invention is is the Servo Control device in order to provide a kind of wheeled tractor, comprising: be arranged at the processing module on wheeled tractor and be arranged at the GPS (Global Position System) GNSS locating module of wheeled tractor front-wheel wheel shaft center;

Described GNSS locating module, at the uniform velocity travel point coordinate of several points on locus circle that at least one circumference formed for obtaining wheeled tractor, described locus circle is rotated to predeterminated position by the bearing circle of described wheeled tractor to keep motionless rear traveling to be formed;

Described processing module, for utilizing the point coordinate of circle approximating method to several points obtained to carry out the Fitting Calculation, determines the trace radius R that described wheeled tractor travels ₀; And the front-wheel spacing L of both sides front-wheel according to described wheeled tractor _twwith trace radius R ₀, determine the front foreign steamer radius of turn that described wheeled tractor travels and according to described radius of turn servo Control is carried out to described wheeled tractor.

The Servo Control device of wheeled tractor as above, described processing module, also for:

The described predeterminated position bearing circle that is described wheeled tractor turn clockwise extreme position extremely, or be rotated counterclockwise extreme position extremely when, the radius of turn of the locus circle travelled according to described wheeled tractor determines the minimal curve radius of described wheeled tractor.

The Servo Control device of wheeled tractor as above, described processing module, also for:

When circle approximating method is set to least square method, carries out the Fitting Calculation by the point coordinate of least square method to several points described, determine the trace radius R that described wheeled tractor travels ₀; Specifically for:

According to the point coordinate (X of several points of described locus circle _i, Y _i) i ∈ (1,2...N), obtain following parameter:

A＝ΣX _i，

B＝ΣY _i，

C＝Σ(X _i+Y _i)，

D＝N·ΣX _i ²-(ΣX _i) ²，

E＝N·ΣY _i ²-(ΣY _i) ²，

F＝N·ΣX _i·Y _i-ΣX _i·ΣY _i，

G＝N·ΣX _i ³+N·ΣX _iY _i ²-Σ(X _i ²+Y _i ²⁾·ΣX _i，

H＝N·ΣY _i ³+N·ΣX _i ²Y _i-Σ(X _i ²+Y _i ²)·ΣY _i；

According to x ²+ y ²+ ax+by+c=0 determines intermediate variable a, b and c, wherein x ∈ X _i, y ∈ Y _i:

$a=\frac{F\&CenterDot;H-E\&CenterDot;G}{D\&CenterDot;E-F^2},b=\frac{D\&CenterDot;H-F\&CenterDot;G}{F^2-D\&CenterDot;E},c=-\frac{C+a\&CenterDot;A+b\&CenterDot;B}{N},$ Wherein N is positive integer;

And according to determine described trace radius.

The Servo Control device of wheeled tractor as above, described processing module, also for:

After determining the radius of turn that described wheeled tractor travels, obtain the distance between axles L of the left side of described wheeled tractor or the front-wheel wheel shaft on right side and rear axle _b, and according to described distance between axles L _bwith the angular relationship of described radius of turn R obtain the front wheel angle that described wheeled tractor travels $\mathrm{\&delta;}=arctan\left(\frac{L_b}{R}\right).$

The Servo Control device of wheeled tractor as above, described processing module, also for:

Obtain the installation predetermined angle δ that rotary angle transmitter is arranged on described wheeled tractor front-wheel _c, 0≤δ _c≤ δ _max;

According to the described front-wheel spacing L taken turns in front side _twwith the angular relationship of described radius of turn R ${\mathrm{tan\&delta;}}_n=\frac{L_b}{R-\frac{L_{tw}}{2}},$ Obtain the corner of wheel in described front side ${\mathrm{\&delta;}}_n=arctan\frac{L_b}{R-\frac{L_{tw}}{2}};$

According to the described front-wheel spacing L of front side foreign steamer _twwith the angular relationship of described radius of turn R ${\mathrm{tan\&delta;}}_w=\frac{L_b}{R+\frac{L_{tw}}{2}},$ Obtain the corner of described front side foreign steamer ${\mathrm{\&delta;}}_w=arctan\frac{L_b}{R+\frac{L_{tw}}{2}};$

If described rotary angle transmitter is installed in described front side on wheel, then according to the corner of taking turns in described front side with described installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of described rotary angle transmitter _c-δ _n;

If described rotary angle transmitter is installed on the foreign steamer of described front side, according to the corner of described front side foreign steamer with described installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of described rotary angle transmitter _c-δ _w;

According to the installation deviation angle of described rotary angle transmitter, determine the setting angle of described rotary angle transmitter.

The Servo Control method of wheeled tractor provided by the invention and device, by obtaining the point coordinate of several points on locus circle, and utilize circle approximating method to carry out the Fitting Calculation to point coordinate, and then determine the radius of turn of wheeled tractor, effectively overcome the problems such as the measuring technique means existed in prior art are coarse and crude, measuring accuracy is low, ensure that the control accuracy of the turning to wheeled tractor, be conducive to the work efficiency improving wheeled tractor.

Accompanying drawing explanation

The flow diagram of the Servo Control method of the wheeled tractor of Fig. 1 given by the embodiment of the present invention;

The schematic diagram of the front wheel angle of the Servo Control method of the wheeled tractor of Fig. 2 given by the embodiment of the present invention;

The schematic diagram of the setting angle of the rotary angle transmitter of the Servo Control method of the wheeled tractor of Fig. 3 given by the embodiment of the present invention;

The structural representation one of the Servo Control device of the wheeled tractor of Fig. 4 given by the embodiment of the present invention;

The structural representation two of the Servo Control device of the wheeled tractor of Fig. 5 given by the embodiment of the present invention.

In figure:

1, GNSS locating module; 2, processing module;

3, load module; 4, output module;

5, memory module; 6, course changing control module.

Embodiment

Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail.Following instance for illustration of the present invention, but is not used for limiting the scope of the invention.

Fig. 1 is the flow diagram of the Servo Control method of given wheeled tractor; Known with reference to accompanying drawing 1, an aspect of of the present present invention provides a kind of Servo Control method of wheeled tractor, comprising:

S1: obtain point coordinate that wheeled tractor at the uniform velocity travels several points on locus circle that at least one circumference formed, locus circle is rotated to predeterminated position by the bearing circle of wheeled tractor to keep motionless rear traveling to be formed;

Wherein, the place at the uniform velocity travelled for wheeled tractor does not limit, those skilled in the art can be arranged according to concrete application demand, as wheeled tractor being arranged on smooth ground, or be arranged on the soils such as field, or also wheeled tractor can be arranged on suitable indoor etc.; Wherein, in order to ensure to wheeled tractor formed locus circle measure accurate reliability, comparatively preferred, tire is considered as rigid wheel, do not consider the lateral slip on tire and ground, and wheeled tractor is arranged on comparatively smooth ground, and the area on ground effectively can ensure that wheeled tractor can exercise at least one circumference, effectively can ensure completing property and the accuracy of the locus circle formed like this, and then improve the degree of accuracy calculating wheeled tractor radius of turn.

In addition, the speed of wheeled tractor when at the uniform velocity travelling is not limited, those skilled in the art can be arranged according to concrete mensuration demand, as the speed of wheeled tractor is set to 5km/h, 10km/h or 15km/h etc., wherein, in order to ensure the number of several points gathering the locus circle that wheeled tractor is formed, comparatively preferred, the speed at the uniform velocity travelled of wheeled tractor is set to be less than or equal to 10km/h, as concrete, the travel speed of wheeled tractor can be set to 5km/h, effectively can ensure number and the accuracy of the point on the locus circle of collection like this.

In addition, the concrete acquisition methods of point coordinate of several points obtained on locus circle and the number of the point of acquisition are not limited, those skilled in the art can be arranged according to concrete design requirement, as the acquisition methods of acquisition point coordinate is set to artificial collection, alignment sensor positions or other devices gather etc., wherein, comparatively preferred, by arrange locating device and GNSS position, obtain the terrestrial coordinate of several points on locus circle, then by the transformational relation of terrestrial coordinate and common coordinate, terrestrial coordinate is converted to two-dimentional common coordinate, namely the coordinate information accurately of several points is obtained, and 100,1000 or more etc. can be set to for the number of point obtained, as long as the method that can realize by obtaining obtains the point coordinate of the point of some, and by the Fitting Calculation to point coordinate, can locus circle be obtained, not repeat them here.

S2: utilize the point coordinate of circle approximating method to several points to carry out the Fitting Calculation, determine the trace radius R that wheeled tractor travels ₀;

Wherein, concrete circle approximating method is not limited, the function that those skilled in the art can realize according to it is arranged arbitrarily, as the methods such as minimum least square method, Lagrange's interpolation, Newton interpolating method, Newton iteration method, interval dichotomy, Secant Method, Jacobi process of iteration and newton Ke Tesi numerical integrating can be adopted, as long as can realize, by carrying out the Fitting Calculation to the point coordinate of several points, trace radius R can being obtained ₀, do not repeat them here.

S3: according to the front-wheel spacing L of wheeled tractor both sides front-wheel _twwith trace radius R ₀, determine the radius of turn that wheeled tractor travels

Wherein, due to the track formed for the inboard wheel being positioned at wheeled tractor according to the locus circle of matching, therefore, for wheeled tractor, its radius of turn also needs on the basis of trace radius, add and the front-wheel spacing of upper half, therefore, the front foreign steamer radius of turn that wheeled rubbish travels if namely obtain is $R=R_0+\frac{L_{tw}}{2}.$

S4: according to radius of turn $R=R_0+\frac{L_{tw}}{2}$ Servo Control is carried out to wheeled tractor.

By the radius of turn obtained, the turning data of wheeled tractor can be recognized, and then be convenient to, to the control of wheeled tractor when field operates, improve the Servo Control to wheeled tractor, and then ensure that the operation quality of wheeled tractor in field.

The Servo Control method of wheeled tractor provided by the invention and device, by obtaining the point coordinate of several points on locus circle, and utilize circle approximating method to carry out the Fitting Calculation to point coordinate, and then determine the radius of turn of wheeled tractor, effectively overcome the problems such as the measuring technique means existed in prior art are coarse and crude, measuring accuracy is low, ensure that the control accuracy of the turning to wheeled tractor, be conducive to the work efficiency improving wheeled tractor.

On the basis of above-described embodiment, continue with reference to accompanying drawing 1 known, due to when wheeled tractor uses, if desired, need to carry out cornering operation, in order to improve the Servo Control ability to wheeled tractor, need the minimal curve radius understanding wheeled tractor, therefore, bearing circle predeterminated position being set to wheeled tractor turn clockwise extreme position extremely, or be rotated counterclockwise extreme position extremely;

Now, according to the minimal curve radius of the radius of turn determination wheeled tractor of the locus circle of wheeled tractor traveling.

By the minimal curve radius of the wheeled tractor of acquisition, further understanding has been had to the cornering limit ability of wheeled tractor, and then when needs wheeled tractor is turned, whether directly cornering operation can be completed according to anticipation wheeled tractor, do not destroy other regions, as directly cornering operation can be completed, namely illustrate that anticipation radius of turn is more than or equal to minimal curve radius, directly can carry out cornering operation; As directly cornering operation cannot be completed, namely illustrate that anticipation radius of turn is less than minimum turning and judges, then need to move, until meet turning condition, can cornering operation be carried out; And then effectively raise the control ability of wheeled tractor, and ensure that the operation effectiveness of wheeled tractor.

On the basis of above-described embodiment, continue with reference to accompanying drawing 1 known, circle approximating method in the technical program is not limited, those skilled in the art can be arranged according to concrete design requirement, wherein, comparatively preferably, circle approximating method is set to least square method, carry out the Fitting Calculation by the point coordinate of least square method to several points, determine the trace radius R that wheeled tractor travels ₀, specifically comprise:

According to the point coordinate (X of several points _i, Y _i) i ∈ (1,2...N), obtain following parameter:

A＝ΣX _i，

B＝ΣY _i，

C＝Σ(X _i+Y _i)，

D＝N·ΣX _i ²-(ΣX _i) ²，

E＝N·ΣY _i ²-(ΣY _i) ²，

F＝N·ΣX _i·Y _i-ΣX _i·ΣY _i，

G＝N·ΣX _i ³+N·ΣX _iY _i ²-Σ(X _i ²+Y _i ²)·ΣX _i，

H＝N·ΣY _i ³+N·ΣX _i ²Y _i-Σ(X _i ²+Y _i ²)·ΣY _i；

According to x ²+ y ²+ ax+by+c=0 determines intermediate variable a, b and c, wherein x ∈ X _i, y ∈ Y _i:

$a=\frac{F\&CenterDot;H-E\&CenterDot;G}{D\&CenterDot;E-F^2},b=\frac{D\&CenterDot;H-F\&CenterDot;G}{F^2-D\&CenterDot;E},c=-\frac{C+a\&CenterDot;A+b\&CenterDot;B}{N},$ Wherein N is positive integer;

According to determine trace radius.

Least square method is the technology comparatively optimized in mathematics, therefore, least square method is adopted to carry out the Fitting Calculation to point coordinate, accuracy and the precision of the Fitting Calculation can be effectively raised, and ensure that the accuracy of the trace radius determined, and then ensure that the accuracy of the Based Intelligent Control to wheeled tractor.

Fig. 2 is the schematic diagram of the front wheel angle of the Servo Control method of given wheeled tractor; On the basis of above-described embodiment, known with reference to accompanying drawing 2, in order to improve the control ability to wheeled tractor, carrying out turning in the process of formation locus circle at wheeled tractor, the front wheel angle information of wheeled tractor can be obtained, concrete:

After determining the radius of turn that wheeled tractor travels, also comprise:

Obtain the distance between axles L of the left side of wheeled tractor or the front-wheel wheel shaft on right side and rear axle _b, and according to distance between axles L _bwith the angular relationship of radius of turn R obtain the front wheel angle that wheeled tractor travels $\mathrm{\&delta;}=arctan\left(\frac{L_b}{R}\right).$

By the front wheel angle information obtained, further increase the control ability to wheeled tractor, radius of turn information and the front wheel angle informix that can consider wheeled tractor control wheeled tractor, ensure that the work capacity of wheeled tractor, be conducive to the propagation and employment in market.

Fig. 3 is the schematic diagram of the setting angle of the rotary angle transmitter of the Servo Control method of given wheeled tractor; On the basis of above-described embodiment, continue with reference to accompanying drawing 3 known, conveniently record the corner information of wheeled tractor, can on the front-wheel of wheeled tractor installing angle sensor, but, because rotary angle transmitter can exist certain error when mounted, therefore, the judgement to corner information can be affected, in order to reduce the alignment error of rotary angle transmitter, need to understand the alignment error allowed when installing angle sensor, concrete comprises:

Obtain the installation predetermined angle δ that rotary angle transmitter is arranged on wheeled tractor front-wheel _c, 0≤δ _c≤ δ _max;

According to the front-wheel spacing L taken turns in front side _twwith the angular relationship of radius of turn R obtain the corner of wheel in front side ${\mathrm{\&delta;}}_n=arctan\frac{L_b}{R-\frac{L_{tw}}{2}};$

According to the front-wheel spacing L of front side foreign steamer _twwith the angular relationship of radius of turn R obtain the corner of front side foreign steamer

If rotary angle transmitter is installed in front side on wheel, then according to the corner of taking turns in front side with installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of rotary angle transmitter _c-δ _n;

If rotary angle transmitter is installed on the foreign steamer of front side, according to the corner of front side foreign steamer with installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of rotary angle transmitter _c-δ _w;

According to the installation deviation angle of rotary angle transmitter, determine the setting angle of rotary angle transmitter.

According to the installation deviation angle obtained, obtain the alignment error that rotary angle transmitter allows, and then determine the setting angle of rotary angle transmitter, as long as the alignment error of rotary angle transmitter is arranged in installation deviation angular range, can mounting condition be met, and then directly can be obtained the corner information of wheeled tractor by the rotary angle transmitter installed.

Fig. 4 is the structural representation of the Servo Control device of given wheeled tractor, another aspect provides a kind of Servo Control device of wheeled tractor, comprising: be arranged at the processing module 2 on wheeled tractor and be arranged at the GPS (Global Position System) GNSS locating module 1 of wheeled tractor front-wheel wheel shaft center;

GNSS locating module 1, at the uniform velocity travels point coordinate of several points on locus circle that at least one circumference formed for obtaining wheeled tractor, locus circle is rotated to predeterminated position by the bearing circle of wheeled tractor to keep motionless rear traveling to be formed;

Processing module 2, for utilizing the point coordinate of circle approximating method to several points obtained to carry out the Fitting Calculation, determines the trace radius R that wheeled tractor travels ₀; And the front-wheel spacing L of both sides front-wheel according to wheeled tractor _twwith trace radius R ₀, determine the front foreign steamer radius of turn that wheeled tractor travels and according to radius of turn servo Control is carried out to wheeled tractor.

Wherein, the concrete structure for concrete GNSS locating module 1 and processing module 2 does not limit, and the function that those skilled in the art can realize according to it is arranged arbitrarily, does not repeat them here; In addition, step implementation process, mode of operation and technique effect that GNSS locating module 1 in the technical program and the functional steps that processing module 2 realizes and the technical program comprise in the technical scheme of step S1-S4 are identical, particular content with reference to above statement content, can not repeat them here.

The Servo Control device of wheeled tractor provided by the invention, the point coordinate of several points on locus circle is obtained by GNSS locating module 1, and utilize processing module 2 to adopt circle approximating method to carry out the Fitting Calculation to point coordinate, and then determine the radius of turn of wheeled tractor, effectively overcome the problems such as the measuring technique means existed in prior art are coarse and crude, measuring accuracy is low, ensure that the control accuracy of the turning to wheeled tractor, be conducive to the work efficiency improving wheeled tractor.

On the basis of above-described embodiment, continue with reference to accompanying drawing 4 known, processing module 2, also for:

The predeterminated position bearing circle that is wheeled tractor turn clockwise extreme position extremely, or be rotated counterclockwise extreme position extremely when, the radius of turn of the locus circle that the wheeled tractor determined travels is the minimal curve radius of wheeled tractor.

The minimal curve radius of the wheeled tractor obtained by processing module 2, further understanding has been had to the cornering limit ability of wheeled tractor, and then when needs wheeled tractor is turned, whether directly cornering operation can be completed according to anticipation wheeled tractor, do not destroy other regions, as directly cornering operation can be completed, namely illustrate that anticipation radius of turn is more than or equal to minimal curve radius, directly can carry out cornering operation; As directly cornering operation cannot be completed, namely illustrate that anticipation radius of turn is less than minimum turning and judges, then need to move, until meet turning condition, can cornering operation be carried out; And then effectively raise the control ability of wheeled tractor, and ensure that the operation effectiveness of wheeled tractor.

On the basis of above-described embodiment, continue with reference to accompanying drawing 4 known, processing module 2, also for:

When circle approximating method is set to least square method, carries out the Fitting Calculation by the point coordinate of least square method to several points, determine the trace radius R that wheeled tractor travels ₀; Specifically for:

According to the point coordinate (X of several points of locus circle _i, Y _i) i ∈ (1,2...N), obtain following parameter:

A＝ΣX _i，

B＝ΣY _i，

C＝Σ(X _i+Y _i)，

D＝N·ΣX _i ²-(ΣX _i) ²，

E＝N·ΣY _i ²-(ΣY _i) ²，

F＝N·ΣX _i·Y _i-ΣX _i·ΣY _i，

G＝N·ΣX _i ³+N·ΣX _iY _i ²-Σ(X _i ²+Y _i ²)·ΣX _i，

H＝N·ΣY _i ³+N·ΣX _i ²Y _i-Σ(X _i ²+Y _i ²)·ΣY _i；

According to x ²+ y ²+ ax+by+c=0 determines intermediate variable a, b and c, wherein x ∈ X _i, y ∈ Y _i:

$a=\frac{F\&CenterDot;H-E\&CenterDot;G}{D\&CenterDot;E-F^2},b=\frac{D\&CenterDot;H-F\&CenterDot;G}{F^2-D\&CenterDot;E},c=-\frac{C+a\&CenterDot;A+b\&CenterDot;B}{N},$ Wherein N is positive integer;

And according to determine trace radius.

Least square method is the technology comparatively optimized in mathematics, therefore, least square method is adopted to carry out the Fitting Calculation to point coordinate, accuracy and the precision of the Fitting Calculation can be effectively raised, and ensure that the accuracy of the trace radius determined, and then ensure that the accuracy of the Based Intelligent Control to wheeled tractor.

On the basis of above-described embodiment, in order to improve the control ability to wheeled tractor, wheeled tractor carry out turn formed locus circle process in, the front wheel angle information of wheeled tractor can be obtained, processing module 2, also for:

After determining the radius of turn that wheeled tractor travels, obtain the distance between axles L of the left side of wheeled tractor or the front-wheel wheel shaft on right side and rear axle _b, and according to distance between axles L _bwith the angular relationship of radius of turn R obtain the front wheel angle that wheeled tractor travels

The front wheel angle information obtained by processing module 2, further increase the control ability to wheeled tractor, radius of turn information and the front wheel angle informix that can consider wheeled tractor control wheeled tractor, ensure that the work capacity of wheeled tractor, be conducive to the propagation and employment in market.

On the basis of above-described embodiment, continue with reference to accompanying drawing 4 known, conveniently record the corner information of wheeled tractor, can on the front-wheel of wheeled tractor installing angle sensor, but, because rotary angle transmitter can exist certain error when mounted, therefore, the judgement to corner information can be affected, in order to reduce the alignment error of rotary angle transmitter, need to understand the alignment error that allows when installing angle sensor, processing module 2, also for:

Obtain the installation predetermined angle δ that rotary angle transmitter is arranged on wheeled tractor front-wheel _c, 0≤δ _c≤ δ _max;

According to the front-wheel spacing L taken turns in front side _twwith the angular relationship of radius of turn R obtain the corner of wheel in front side

According to the front-wheel spacing L of front side foreign steamer _twwith the angular relationship of radius of turn R obtain the corner of front side foreign steamer ${\mathrm{\&delta;}}_w=arctan\frac{L_b}{R+\frac{L_{tw}}{2}};$

If rotary angle transmitter is installed in front side on wheel, then according to the corner of taking turns in front side with installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of rotary angle transmitter _c-δ _n;

If rotary angle transmitter is installed on the foreign steamer of front side, according to the corner of front side foreign steamer with installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of rotary angle transmitter _c-δ _w;

According to the installation deviation angle of rotary angle transmitter, determine the setting angle of rotary angle transmitter.

According to the installation deviation angle that processing module 2 obtains, obtain the alignment error that rotary angle transmitter allows, and then determine the setting angle of rotary angle transmitter, as long as the alignment error of rotary angle transmitter is arranged in installation deviation angular range, can mounting condition be met, and then directly can be obtained the corner information of wheeled tractor by the rotary angle transmitter installed.

During embody rule, Fig. 5 is the structural representation two of the Servo Control device of given wheeled tractor, known with reference to accompanying drawing 5, the Servo Control device of the wheeled tractor in the technical program can be set to comprise the utility appliance such as processing module 2, load module 3, output module 4, memory module 5, course changing control module 6 and GNSS locating module 1, the Servo Control device of this wheeled tractor is set to the embedded type terminal equipment of the airborne monitoring operation demand of applicable tractor; Wherein, processing module 2 is the core that whole device controls, and is also the key modules calculating radius of turn and front wheel angle; And for load module 3, output module 4 and memory module 5, load module 3 can be set to keyboard and touch panel device, it is mutual and arrange measurement parameter to be mainly used in man-machine interface; Output module 4 can select LCD display, for showing real-time measurement track and the measurement result of tractor radius of turn; Memory module 5 can select flash card, measures trail file and measurement result in real time for record and storage tractor; And for course changing control module 6, it is connected with processing module 2, for in the process of being undertaken demarcating by rotary angle transmitter, export a control corner determined, the installation effectively raised for rotary angle transmitter controls, and effectively reduces the error that rotary angle transmitter produces in installation process; By the above-mentioned modules arranged, effectively raise practicality and the intelligence degree of the Servo Control device of wheeled tractor; In addition, for GNSS locating module 1, for providing the current location of wheeled tractor in real time, obtaining the point coordinate of the point on the locus circle of wheeled tractor traveling, and may be used for front wheel angle measurement and calibration; Certain, those skilled in the art can also increase other application module or equipment according to concrete application demand, as increased Intelligent communication module, for carrying out communicating to connect etc. with the terminal device such as mobile phone, computer, do not repeat them here.

In addition, in order to the surveying work of the radius of turn and front wheel angle that ensure wheeled tractor better, its device is preferably designed as the firm housing of three anti-technical grades with " dust-proof, shockproof, waterproof ", and then reach the request for utilization of agricultural machinery car-mounted terminal, and effectively can ensure the reliability that this device uses.

When installing this Servo Control device, can processing module 2, load module 3 and output module 4 etc. be installed in Operator's Cab of Roller Tractor, and GNSS locating device is installed and the front axle center on pilothouse, especially for the GNSS external antenna in GNSS locating device, GNSS external antenna is installed on the front axle center O on pilothouse _a.

After installing, namely measure the radius of turn of wheeled tractor and front wheel angle by control device, control effectively to wheeled tractor with the radius of turn by recording and front wheel angle information, concrete measuring process is:

Measure place and choose smooth ground, place size should be able to allow tractor to carry out circle traveling.Start minimal curve radius measuring process on the left of tractor by the human-computer interaction interface of determinator, tractor steering dish is gone to left side extreme position simultaneously, keep motionless, at low speed more than a circle.

In measuring process, determinator real time record wheeled tractor current location also shows traveling locus circle, and when travelling longer than a circle, locus circle is closed.

Now, terminate measuring process by human-computer interaction interface, calculate the minimal curve radius on the left of wheeled tractor by processing module 2, and measurement result can be exported by human-computer interaction interface; Then steering wheel of tractor is gone to right side extreme position, measure the minimal curve radius on the right side of tractor, and measurement result can be exported by human-computer interaction interface, effectively can be controlled wheeled tractor by the minimal curve radius measured, improve the Job Operations ability of this wheeled tractor.

In addition, on this wheeled tractor, can also installing angle sensor, rotary angle transmitter is one of key component of tractor automatic navigation system based on GNSS satellite location, rotary angle transmitter can be arranged on tractor front-wheel axle center place, for measuring the steering angle of front-wheel; Carrying out front wheel angle sensor in installation process, unavoidably there is installation deviation, in order to eliminate the initial installation deviation of front wheel angle sensor, need the demarcation carrying out rotary angle transmitter, method provided by the invention also can be used for the initial installation deviation value of demarcating front wheel angle sensor with device, concrete process can with reference to foregoing description content, do not repeat them here, by said method and device to the acquisition of the installation deviation value of rotary angle transmitter, effectively ensure that the installation accuracy of rotary angle transmitter.

In terms of existing technologies, the technical program has the following advantages:

(1) can the functional module such as set handling module 2, load module 3, output module 4, memory module 5, GNSS locating module 1, construct the vehicle-mounted embedded type terminal device of wheeled tractor, realize the automatic measurement of wheeled tractor minimal curve radius and front wheel angle, measuring process real-time is good, easy and simple to handle, and then the control accuracy that improve wheeled tractor and ability;

(2) apply least square method and solve minimal curve radius and front wheel angle, drastically increase computational accuracy;

(3) point coordinate of several points on the locus circle of wheeled tractor traveling are obtained based on GNSS locating module 1, ensure that the accuracy and reliability of the point coordinate of the point of acquisition, and the Based Intelligent Control effectively raised wheeled tractor, improve the work capacity of wheeled tractor.

Last it is noted that above each embodiment is only in order to illustrate technical scheme of the present invention, be not intended to limit; Although with reference to foregoing embodiments to invention has been detailed description, those of ordinary skill in the art is to be understood that: it still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein some or all of technical characteristic; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the scope of various embodiments of the present invention technical scheme.

Claims (10)

1. a Servo Control method for wheeled tractor, is characterized in that, comprising:

Obtain point coordinate that wheeled tractor at the uniform velocity travels several points on locus circle that at least one circumference formed, described locus circle is rotated to predeterminated position by the bearing circle of described wheeled tractor to keep motionless rear traveling to be formed;

Utilize the point coordinate of circle approximating method to several points described to carry out the Fitting Calculation, determine the trace radius R that described wheeled tractor travels ₀;

According to the front-wheel spacing L of described wheeled tractor both sides front-wheel _twwith described trace radius R ₀, determine the front foreign steamer radius of turn that described wheeled tractor travels

According to described radius of turn servo Control is carried out to described wheeled tractor.

2. the Servo Control method of wheeled tractor according to claim 1, is characterized in that, the bearing circle that described predeterminated position is described wheeled tractor turn clockwise extreme position extremely, or be rotated counterclockwise extreme position extremely;

Accordingly, the radius of turn of the locus circle travelled according to described wheeled tractor determines the minimal curve radius of described wheeled tractor.

3. the Servo Control method of wheeled tractor according to claim 1, it is characterized in that, described circle approximating method is least square method, carries out the Fitting Calculation, determine the trace radius R that described wheeled tractor travels by the point coordinate of least square method to several points described ₀, specifically comprise:

According to the point coordinate (X of several points described _i, Y _i) i ∈ (1,2...N), obtain following parameter:

A＝ΣX _i，

B＝ΣY _i，

C＝Σ(X _i+Y _i)，

D＝N·ΣX _i ²-(ΣX _i) ²，

E＝N·ΣY _i ²-(ΣY _i) ²，

F＝N·ΣX _i·Y _i-ΣX _i·ΣY _i，

G＝N·ΣX _i ³+N·ΣX _iY _i ²-Σ(X _i ²+Y _i ²)·ΣX _i，

H＝N·ΣY _i ³+N·ΣX _i ²Y _i-Σ(X _i ²+Y _i ²)·ΣY _i；

According to x ²+ y ²+ ax+by+c=0 determines intermediate variable a, b and c, wherein x ∈ X _i, y ∈ Y _i:

$\begin{array}{ccc}a=\frac{F\&CenterDot;H-E\&CenterDot;G}{D\&CenterDot;E-F^2},& b=\frac{D\&CenterDot;H-F\&CenterDot;G}{F^2-D\&CenterDot;E},& c=-\frac{C+a\&CenterDot;A+b\&CenterDot;B}{N}\end{array},$ Wherein N is positive integer;

According to determine described trace radius.

4. the Servo Control method of the wheeled tractor according to claim 1 or 3, is characterized in that, described determine the radius of turn that described wheeled tractor travels after, also comprise:

Obtain the distance between axles L of the left side of described wheeled tractor or the front-wheel wheel shaft on right side and rear axle _b, and according to described distance between axles L _bwith the angular relationship of described radius of turn R obtain the front wheel angle that described wheeled tractor travels

5. the Servo Control method of wheeled tractor according to claim 4, is characterized in that, also comprise:

Obtain the installation predetermined angle δ that rotary angle transmitter is arranged on described wheeled tractor front-wheel _c, 0≤δ _c≤ δ _max;

According to the described front-wheel spacing L taken turns in front side _twwith the angular relationship of described radius of turn R ${\mathrm{tan\&delta;}}_n=\frac{L_b}{R-\frac{L_{tw}}{2}},$ Obtain the corner of wheel in described front side ${\mathrm{\&delta;}}_n=arctan\frac{L_b}{R-\frac{L_{tw}}{2}};$

According to the described front-wheel spacing L of front side foreign steamer _twwith the angular relationship of described radius of turn R ${\mathrm{tan\&delta;}}_w=\frac{L_b}{R+\frac{L_{tw}}{2}},$ Obtain the corner of described front side foreign steamer ${\mathrm{\&delta;}}_w=arctan\frac{L_b}{R+\frac{L_{tw}}{2}};$

If described rotary angle transmitter is installed in described front side on wheel, then according to the corner of taking turns in described front side with described installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of described rotary angle transmitter _c-δ _n;

If described rotary angle transmitter is installed on the foreign steamer of described front side, according to the corner of described front side foreign steamer with described installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of described rotary angle transmitter _c-δ _w;

According to the installation deviation angle of described rotary angle transmitter, determine the setting angle of described rotary angle transmitter.

6. a Servo Control device for wheeled tractor, is characterized in that, comprising: be arranged at the processing module on wheeled tractor and be arranged at the GPS (Global Position System) GNSS locating module of wheeled tractor front-wheel wheel shaft center;

Described GNSS locating module, at the uniform velocity travel point coordinate of several points on locus circle that at least one circumference formed for obtaining wheeled tractor, described locus circle is rotated to predeterminated position by the bearing circle of described wheeled tractor to keep motionless rear traveling to be formed;

Described processing module, for utilizing the point coordinate of circle approximating method to several points obtained to carry out the Fitting Calculation, determines the trace radius R that described wheeled tractor travels ₀; And the front-wheel spacing L of both sides front-wheel according to described wheeled tractor _twwith trace radius R ₀, determine the front foreign steamer radius of turn that described wheeled tractor travels and according to described radius of turn servo Control is carried out to described wheeled tractor.

7. the Servo Control device of wheeled tractor according to claim 6, is characterized in that, described processing module, also for:

The described predeterminated position bearing circle that is described wheeled tractor turn clockwise extreme position extremely, or be rotated counterclockwise extreme position extremely when, the radius of turn of the locus circle travelled according to described wheeled tractor determines the minimal curve radius of described wheeled tractor.

8. the Servo Control device of wheeled tractor according to claim 6, is characterized in that, described processing module, also for:

When circle approximating method is set to least square method, carries out the Fitting Calculation by the point coordinate of least square method to several points described, determine the trace radius R that described wheeled tractor travels ₀; Specifically for:

According to the point coordinate (X of several points of described locus circle _i, Y _i) i ∈ (1,2...N), obtain following parameter:

A＝ΣX _i，

B＝ΣY _i，

C＝Σ(X _i+Y _i)，

D＝N·ΣX _i ²-(ΣX _i) ²，

E＝N·ΣY _i ²-(ΣY _i) ²，

F＝N·ΣX _i·Y _i-ΣX _i·ΣY _i，

G＝N·ΣX _i ³+N·ΣX _iY _i ²-Σ(X _i ²+Y _i ²)·ΣX _i，

H＝N·ΣY _i ³+N·ΣX _i ²Y _i-Σ(X _i ²+Y _i ²)·ΣY _i；

According to x ²+ y ²+ ax+by+c=0 determines intermediate variable a, b and c, wherein x ∈ X _i, y ∈ Y _i:

$\begin{array}{ccc}a=\frac{F\&CenterDot;H-E\&CenterDot;G}{D\&CenterDot;E-F^2},& b=\frac{D\&CenterDot;H-F\&CenterDot;G}{F^2-D\&CenterDot;E},& c=-\frac{C+a\&CenterDot;A+b\&CenterDot;B}{N}\end{array},$ Wherein N is positive integer;

And according to determine described trace radius.

9. the Servo Control device of the wheeled tractor according to claim 6 or 8, is characterized in that, described processing module, also for:

After determining the radius of turn that described wheeled tractor travels, obtain the distance between axles L of the left side of described wheeled tractor or the front-wheel wheel shaft on right side and rear axle _b, and according to described distance between axles L _bwith the angular relationship of described radius of turn R obtain the front wheel angle that described wheeled tractor travels $\mathrm{\&delta;}=arctan\left(\frac{L_b}{R}\right).$

10. the Servo Control device of wheeled tractor according to claim 9, is characterized in that, described processing module, also for:

Obtain the installation predetermined angle δ that rotary angle transmitter is arranged on described wheeled tractor front-wheel _c, 0≤δ _c≤ δ _max;

According to the described front-wheel spacing L taken turns in front side _twwith the angular relationship of described radius of turn R ${\mathrm{tan\&delta;}}_n=\frac{L_b}{R-\frac{L_{tw}}{2}},$ Obtain the corner of wheel in described front side ${\mathrm{\&delta;}}_n=arctan\frac{L_b}{R-\frac{L_{tw}}{2}};$

According to the described front-wheel spacing L of front side foreign steamer _twwith the angular relationship of described radius of turn R ${\mathrm{tan\&delta;}}_w=\frac{L_b}{R+\frac{L_{tw}}{2}},$ Obtain the corner of described front side foreign steamer ${\mathrm{\&delta;}}_w=arctan\frac{L_b}{R+\frac{L_{tw}}{2}};$

If described rotary angle transmitter is installed in described front side on wheel, then according to the corner of taking turns in described front side with described installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of described rotary angle transmitter _c-δ _n;

If described rotary angle transmitter is installed on the foreign steamer of described front side, according to the corner of described front side foreign steamer with described installation predetermined angle δ _c, obtain the installation deviation angle delta δ=δ of described rotary angle transmitter _c-δ _w;

According to the installation deviation angle of described rotary angle transmitter, determine the setting angle of described rotary angle transmitter.