CN101520653B - Method for controlling curves by polar coordinate polynomial differential difference compensation milling - Google Patents

Abstract

The invention relates to a method for controlling curves by polar coordinate polynomial differential difference compensating milling, and belongs to an on-line cutting method of a production line of alarge specification, high grade, thick wall, round and square welded pipe. The method is characterized in that the polar coordinate difference compensating milling is adopted, two saw blades are arra nged on two main shafts of a diagonal of a rotating disk; during work, the rotating disk and two feed main shafts perform curve difference compensating running and cutting pipes (sectional materials) along the track of the cross sectional shape of a cut piece, one rotary servo shaft controls feeding angles of the saw blades, two feed servo shafts perform radial motion to control the depth of the saw blades, and three shafts perform difference compensating simultaneously to a circular shape, a square rectangular shape, and the like; and a numerical control system is adopted, so that a feed curve fits a rotation angle of a shape rotating disk of a steel pipe to cut the steel pipe according to length specifications of the steel pipe, polynomial differential difference compensating of the position and polar coordinate phasor difference compensation of the speed are realized, and a rotation shaft and the feed shaft fit various curves better. A cutter has stable running and no chattering so as to prolong the service life of the saw blades to a large extent.

Description

Method for controlling curves by polar coordinate polynomial differential difference compensation milling

Technical field

The present invention relates to the online cutting-off method of a kind of big specification, high grade of steel, heavy wall, circular side's rectangle welded pipe product line, particularly a kind of method for controlling curves by polar coordinate polynomial differential difference compensation milling.

Background technology

Producing petroleum pipe line, rock gas, chemical industry, municipal water gas piping; The perhaps manufacturing of automobile, agricultural machinery, railway carriage, boats and ships, on the guardrail of highway, the production line of light industry with the steel pipes with straight of bin and container furniture etc., various shape steel tube, flying saw is a key equipment.Its effect is that the tubing of the automated production of online production carries out fixed ruler cutting.

At present, the sawing form of system controlled by computer fixed length flying saw is swing arm, flat push type or roll-turning, to big specification tubing, can't onlinely cut off; On the motion synthesis mode of milling, also has Cartesian coordinate type, the Cartesian coordinate type milling is that two saw blades are installed on the main shaft of double-deck slide unit of right-angled intersection, during work, slide unit drives the saw head and does the motion of difference benefit, along the cross sectional shape of steel pipe it is cut off that its physical construction is bigger, the equipment poor rigidity, tool setting has certain wearing and tearing, chatter etc.;

Summary of the invention

In order to overcome the shortcoming that exists in the prior art, the control method that a kind of profiling milling is provided is a method for controlling curves by polar coordinate polynomial differential difference compensation milling, thereby solves the cut-out problem of big specification, high grade of steel, heavy wall welded pipe product line

The present invention solves its technical matters, the technical scheme of being taked is: method for controlling curves by polar coordinate polynomial differential difference compensation milling, it is characterized in that: adopt the polar coordinates type difference compensation milling, be that two saw blades are installed on two cornerwise main shafts of a rotating circular disk, during work, rotating disk and two feeding main shafts are done the curve difference compensating operation, and will manage cut-out along the cross sectional shape track of being cut part, realize the polynomial differential interpolation of position and the polar coordinates phasor difference benefit of speed, turning axle and feed shaft well simulate various curves, feeding angle by a rotary servovalve axle control saw blade, two feed servo diameters of axle are to the depth of motion control saw blade, and three action differences are simultaneously mended out circles, side's rectangle etc.;

Adopt digital control system, relevant parameter is input to digital control system CPU inside by HMI, position, speed after will calculating are imported in the positioning system again, set feed servo device, the servo milling curve of rotating disk by locating module, pass to servoamplifier, pass to servomotor by servoamplifier again, carry out the encoder position feedback, simulate the feeding curve of blade, fit out the profile of steel pipe according to the length specification of steel pipe, the rotating disk anglec of rotation is cut off steel pipe;

According to the polar coordinates formula, every corresponding variable θ just calculates corresponding feed value ρ, and rotary servovalve and feed servo just can interpolation go out straight line.

The feeding angle of rotary servovalve axle control saw blade, two feed servo diameters of axle are to the depth of motion control saw blade, and three action differences are simultaneously mended out circle, square rectangles.

1) the linear interpolation algorithmic formula is as follows:

ρ ₀＝X0/cos?θ ₀

ρ＝X0/cosθ；

ρ ₀＝Y0/cos(90°-θ ₀)

＝Y0/sin?θ ₀；

ρ′＝Y0/cos(90°-θ)

＝Y0/sinθ；

Wherein:

ρ ₀--------------the utmost point footpath that----is known

θ ₀=arctan (Y0/X0)------------------initial cuts angle

θ=θ ₀-Δ θ------------------rotation variable cutting angle

Half of the width of X0------------------rectangular tube

Half of the height of Y0------------------rectangular tube

Every so corresponding variable θ just calculates corresponding feed value ρ, and rotary servovalve and feed servo just can interpolation go out straight line.

2) the polar coordinates inside radius is the circular arc of r, and the interpolation formula is as follows:

ρ ²-2ρρ ₀cos(θ-θ ₀)＝r ²-ρ ₀ ²

ρ＝ρ ₀cos(θ-θ ₀)+[r ²-ρ ₀ ²sin ²(θ-θ ₀)] ^1/2

Wherein:

ρ ₀--------------the utmost point footpath in----center of circle

θ ₀=--------------the polar angle in----center of circle

θ------------------rotation variable cutting angle

ρ------------------any utmost point of some footpath on the circle

Every so corresponding variable θ just calculates corresponding feed value ρ, and rotary servovalve and feed servo just can interpolation go out circular curve.

Cutting example (as Fig. 3): the rectangular tube specification is 270 * 580mm, and wall thickness 16mm saw blade diameter is Φ 355, and polar initial point is the center of rectangular tube.At this moment

Utmost point footpath ρ=(X0+R-γ)/cos θ

ρ＝(Y0+R-γ)/sinθ

Half of the width of X0----------------rectangular tube

Half of the height of Y0----------------rectangular tube

R------------------saw blade radius

γ--------------the wall thickness of----rectangular tube

θ ₀=arctan (Y0+R-γ)/(X0+R-γ) gets θ=θ ₀-Δ θ=θ ₀Every minimizing 0.5 degree in-n*0.5 ° of such θ angle, i.e. each θ, correspondence goes out a ρ value; Also be that rotating disk whenever rotates to an angle, just can calculate the position of corresponding feed shaft; , can be decomposed into a bit along the speed V of tube wall for arbitrarily along the speed V of utmost point footpath direction _Feeding=V*sin θ and along the speed V of sense of rotation _Rotation=V*cos θ so just can interpolation go out straight line.

When the circular arc of sawing corner, according to formula:

ρ＝ρ ₀cos(θ-θ ₀)+[r ²-ρ ₀ ²s?in ²(θ-θ ₀)] ^1/2

Wherein: ρ ₀=[(X0-r1) ²+ (Y0-r1) ²] ^1/2

θ ₀＝arctan(X0-r1/Y0-r1)

r＝R+r1-γ

The r1------------------knuckle radius

Equally, the every minimizing in θ angle 0.5 degree, i.e. each θ, correspondence goes out a ρ value, also is that rotating disk whenever rotates to an angle, and just can calculate the position of the feed shaft of correspondence; Determine the rotational speed of rotating disk, just can calculate the speed of feeding, the poor complementarity problem of garden arc part has also solved like this.

The invention has the beneficial effects as follows: the polar coordinates type milling is that two saw blades are installed on two cornerwise main shafts of a rotating circular disk.During work, rotating disk and two feeding main shafts are done the curve difference compensating operation, and will manage cut-out along the cross sectional shape track of being cut part.Realize the polynomial differential interpolation of position and the polar coordinates phasor difference benefit of speed, turning axle and feed shaft well simulate various curves.Cutter operates steadily, does not have chatter, has largely prolonged the serviceable life of saw blade.

Description of drawings

Fig. 1 is that polar coordinates straight line difference of the present invention is mended principle schematic;

Fig. 2 is a polar coordinates circular interpolation principle schematic of the present invention;

Fig. 3 is a milling rectangular steel pipe method for controlling curves synoptic diagram of the present invention;

Fig. 4 is a control principle block scheme of the present invention;

Fig. 5 is a milling pipe method for controlling curves synoptic diagram of the present invention;

Fig. 6 is milling side of the present invention, quarter bend method for controlling curves synoptic diagram.

Shown in the figure: saw blade 1, the incision straight path 2, Cutting trajectory 3, feeding withdrawing 4, return and treat seat in the plane 5, circle, steel pipe workpiece 6.

The present invention will be further described below in conjunction with drawings and Examples.

Adopt the polar coordinates type difference compensation milling.The polar coordinates type milling is that two saw blades are installed on two cornerwise main shafts of a rotating circular disk.During work, rotating disk and two feeding main shafts are done the curve difference compensating operation, and will manage (section bar) along the cross sectional shape track of being cut part and cut off.Realize the polynomial differential interpolation of position and the polar coordinates phasor difference benefit of speed, turning axle and feed shaft well simulate various curves.

Flying saw adopts the alloy cutter head milling saw blade of import.Like this under the situation of 400～600r/min, this saw blade can cut high grade of steel (X80, N80), the material of heavy wall (about 20mm).

Adopt digital control system, relevant parameter is input to digital control system CPU inside by HMI, position, speed after will calculating are imported in the positioning system again, set the feed servo device by locating module, the servo milling curve of rotating disk is passed to servoamplifier, pass to servomotor, carry out the encoder position feedback, simulate the feeding curve of blade, fit out the shape rotating disk anglec of rotation cut-out steel pipe of steel pipe according to the length and width specification of steel pipe;

Draw up the feeding curve of blade.In cutting during pipe, this curve is that the tangential direction according to pipe enters tube wall, accomplishes that the number of teeth that participates in cutting is minimum.When the cutting rectangular tube, it is minimum to cut the number of teeth that also will participate in cutting at the right-angle side of steel pipe.

Embodiment 1

When the cutting pipe (as shown in Figure 5), process is as follows:

1) at first, when saw blade had just been cut tube wall, in order to reduce the serviceable life that resistance to cutting prolongs saw blade, along the tangential direction incision of tube wall, this moment, rotating disk and feeding were moved simultaneously, realized cutting by polar coordinates straight line algorithmic formula;

2) secondly, after saw blade was cut tube wall, radial feed stopped action, and rotating disk turns clockwise about 190 °, cuts off steel pipe;

3) the saw blade radial feed is return position of readiness, the rotating disk transfixion;

4) rotating disk goes back to original position, and feeding is static, finishes cutting at one time.

Embodiment 2

When the cutting square tube (as shown in Figure 6), feed servo mechanism and rotating disk rotating mechanism move simultaneously, by the fillet place of rectangular piece, in vertical direction incision tube wall.Center with rectangular tube is polar initial point, at this moment, and position more arbitrarily:

Feed shaft: ρ=(X0+R-γ)/cos θ;

Turntable shaft: θ degree;

This point prolongs the cutting speed V (mm/s) of tube wall direction:

Feed servo speed of feed V _Feeding=V*sin θ (mm/s);

The speed V that rotating disk turns clockwise _Rotation=V*cos θ (mm/s) is converted to angular unit: 10800V*cos ²θ/(X0+R-γ) * π;

Thus, arbitrarily any position, speed on the straight line, differential turns to the Δ θ at 0.5 ° of angle, and the multistep position after the micronized, speed are imported positioning system into, can simulate straight line;

When the circular arc of saw blade sawing corner:

Feed shaft: ρ=ρ ₀Cos (θ-θ ₀)+[r ²-ρ ₀ ²S in ²(θ-θ ₀)] ^1/2

Turntable shaft: θ degree;

The speed that rotating disk turns clockwise: 10800V*cos θ/(X0+R-γ) * π (degree/minute)

Feed servo speed of feed V _Feeding=(ρ 1-ρ)/V (mm/s)

Thus, arbitrarily any position, speed on the circular arc, differential turns to the Δ θ at 0.5 ° of angle, realizes the level and smooth cutting of circular arc portion.

Relevant parameter is input to digital control system CPU inside by HMI, position, speed after will calculating are imported in the positioning system again, can be simultaneously, the shape rotating disk Rotate 180 that fits out steel pipe according to the length and width specification of steel pipe ° cuts off steel pipe, and feeding and rotating disk are return position of readiness respectively and finished cutting at one time.

Claims (2)

1. method for controlling curves by polar coordinate polynomial differential difference compensation milling, it is characterized in that: adopt the polar coordinates type difference compensation milling, be that two saw blades are installed on two cornerwise main shafts of a rotating circular disk, during work, rotating disk and two feeding main shafts are done the curve difference compensating operation, and will manage cut-out along the cross sectional shape track of being cut part, realize the polynomial differential interpolation of position and the polar coordinates phasor difference benefit of speed, turning axle and feed shaft well simulate various curves, feeding angle by a rotary servovalve axle control saw blade, two feed servo diameters of axle are to the depth of motion control saw blade, and three action differences are simultaneously mended out circles, side's rectangle etc.;

Adopt digital control system, relevant parameter is input to digital control system CPU inside by HMI, position, speed after will calculating are imported in the positioning system again, set feed servo device, the servo milling curve of rotating disk by locating module, pass to servoamplifier, pass to servomotor by servoamplifier again, carry out the encoder position feedback, simulate the feeding curve of blade, fit out the profile of steel pipe according to the length specification of steel pipe, the rotating disk anglec of rotation is cut off steel pipe;

2. method for controlling curves by polar coordinate polynomial differential difference compensation milling according to claim 1, it is characterized in that: according to the polar coordinates formula, every corresponding variable θ just calculates corresponding feed value ρ, and rotary servovalve and feed servo just can interpolation go out straight line.

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