CN105033352A - Band sawing machine constant power sawing control method and intelligent band sawing machine thereof - Google Patents

Abstract

The invention relates to a band sawing machine constant power sawing control method and an intelligent band sawing machine thereof; the intelligent band sawing machine comprises a control system, a saw frame system, a feeding system and a clamp mechanism; a rotary encoder is arranged on a rotary shaft of a driven saw wheel, and rotary speed of the driven saw wheel is detected in real time; a power sensor detects a frequency converter feedback current, and the current value is sent to a lower computer through the rotary encoder; the lower computer collects the rotary speed and torque data of a main motor, uses a feeding flow valve control motor to adjust the opening of the feeding flow valve, thus changing lifting speed of an oil cylinder piston rod; the lower computer can adjust the pressure of an electric-hydraulic proportional overflow valve through sensor feedbacks, thus controlling tensile force of a tensioning oil cylinder. The power of the driving main motor is fully used, sawing condition influences on the saw blade life and different material feeding force limit conditions are considered, thus realizing intelligent sawing of the band sawing machine, and effectively prolonging fatigue life of the saw blade.

Description

The control method of band sawing machine invariable power sawing and intelligent band sawing machine thereof

Technical field

The present invention relates to band sawing machine technical field, particularly relate to a kind ofly consider saw blade fatigue life, power of motor utilizes the control method of maximized band sawing machine invariable power sawing and intelligent band sawing machine thereof.

Background technology

Modern Manufacturing Industry is towards the future development of efficient, high accuracy and economy, and sawing, as the starting point of metal cutting process, has become integral link important in part process.Domestic band sawing machine product and external advanced band sawing machine product gap are very large, especially there is degree of intelligence and the low problem of cutting-rate.As the first operation of part processing, the effect of sawing and efficiency often affect the efficiency of whole production line, improve the cutting-rate of band sawing machine, sawing can be avoided to become the bottleneck of whole production line.

At present, control method and the intelligent band sawing machine thereof of the sawing of metal cutting band saw bed invariable power are band sawing machine design focal point and difficult point, and the domestic Patents being directed to intelligent saw cutting system mainly contains:

Chinese invention patent (patent announcement number is CN102672271B) discloses one " permanent sawing force becomes saw frame feed system and the method thereof of feed speed ", propose touch-screen select and arrange shape of cross section, by detecting workpiece hardness, determine saw blade saw cutting speed; Measured the real time position of sawing again by distance measuring sensor, according to the shape of cross section arranged and real-time sawing position, choose the built-in amount of feeding in systems in which, calculate feed speed, become the saw frame feedforward control of feed speed in real time; System according to the sawing force value that pressure sensor obtains, compares with given sawing force, implements permanent sawing force closed-loop control in real time.

Chinese invention patent (patent announcement number is CN102063086B) discloses one " constant-power sawing control device of band sawing machine ", by being arranged on the displacement detecting of feeding displacement transducer in band sawing machine feed cylinder, realize the Real-time Feedback of sawing process bands for band sawing load, based on pid control algorithm, compare with setting sawing load according to actual sawing load, regulate sawing feed speed, thus implement sawing load (invariable power) constant control of sawing process.

Chinese invention patent (patent announcement number is CN102151899B) discloses one " Intelligent band sawing machine ", based on saw disc frequency conversion drive, set up driving torque sensing device, saw blade tension checkout gear and electro-hydraulic servo feed arrangement, by change in torque, Dynamic parameter adjustment is carried out to frequency converter, detect based on saw blade tension, realized the Based Intelligent Control demand of sawing load by electro-hydraulic servo feed arrangement.

There is certain limitation in above-mentioned benefiting our pursuits: (1) does not consider how given sawing force is arranged, and cannot make full use of the power driving mair motor, also not consider that different operating mode sawing process is on the impact of blade life; (2) under different materials, different sawing operating mode, saw blade feeding drag (corresponding with hardness and sawing force value) and the ratio of sawing drag are not constant, the feedforward control fed back by hardness determination and the feedback control fed back by sawing force value, effectively can not realize the closed-loop control of given sawing force.(3) saw blade tension and sawing drag are not directly proportional as described in above-mentioned existing patent, based on this FEEDBACK CONTROL, effectively can not realize the control of given sawing force.

Therefore, be necessary in existing Research foundation achievement, do further innovation.

Summary of the invention

Technical problem to be solved by this invention is, provide a kind ofly consider saw blade fatigue life, power of motor utilizes the control method of maximized band sawing machine invariable power sawing and intelligent band sawing machine thereof.

The present invention is achieved in that the control method and intelligent band sawing machine thereof that provide the sawing of a kind of band sawing machine invariable power, and band sawing machine comprises control system, saw frame system, feed system and clamping device, control system comprises the host computer with man-machine interface, there is the slave computer of Programmable Logic Controller, D/A modular converter, frequency converter, mair motor, power sensor, rotary encoder and deceleration device, saw frame system comprises saw frame, Initiative saw wheel, driven saw wheel, bands for band, tensioning hydro-cylinder, sensor, workpiece sensing bar and electricity liquid ratio relief valve, feed system comprises feed cylinder, feeding flow valve, feeding flow valve control motor, hydraulic pump, feeding displacement transducer, tensioning reversal valve, feed reverse valve, clamping reversal valve and fuel tank, the control method of band sawing machine invariable power sawing comprises the permanent sawing force control method of band sawing machine allowing the saw cutting speed of band sawing machine keep the constant permanent saw cutting speed control method of band sawing machine and to allow the sawing force of band sawing machine remain constant, and the permanent sawing force control method of band sawing machine comprises the steps:

1.0 first, chooses the reference saw shear force F of bands for band according to following methods _xc:

1.1 control systems calculate specified sawing force F according to the rated power of mair motor according to formula (A) _x0:

$F_{x0}=\frac{P\·\mathrm{\η}}{v_s}---\left(A\right)$

In formula, P is the rated power of mair motor, and η is mechanical efficiency, v _sfor setting saw cutting speed; Setting saw cutting speed v _schanging according to the difference of workpiece material, is empirical data;

1.2 control systems are according to the tensile force F of tensioning hydro-cylinder _pthe theoretical sawing force F of bands for band is calculated according to formula (B) _x1and adopt formula (C) to carry out bands for band fatigue strength n _{σ τ}checking computations, make theoretical sawing force F _x1both meet formula (B) and also meet formula (C):

$F_{x1}=\frac{F_p(L_0+\mathrm{\π}R)(e^{f^{\′}\mathrm{\π}}-1)}{L_0(1.5+0.5e^{f^{\′}\mathrm{\π}})+R(\mathrm{\π}+\frac{e^{f^{\′}\mathrm{\π}}-1}{f^{\′}})}---\left(B\right)$

In formula, L ₀for the centre-to-centre spacing of driven wheel; R is driven wheel radius; wherein f is the confficient of static friction of bands for band and driven wheel, n _xfor the tensioning allowance factor;

$n_{\mathrm{\σ}\mathrm{\τ}}=\frac{n_{\mathrm{\σ}}\·n_{\mathrm{\τ}}}{\sqrt{n_{\mathrm{\σ}}^2+n_{\mathrm{\τ}}^2}}\≥n_f---\left(C\right)$

In formula, n _f(≤1) be fatigue safety factor, usually get n _f=1.1;

$\begin{array}{c}{n}_{\mathrm{\σ}}=\frac{0.28{\mathrm{\σ}}_b}{1.2{\mathrm{\σ}}_a+0.3{\mathrm{\σ}}_m},n_{\mathrm{\τ}}=\frac{0.23{\mathrm{\σ}}_b}{1.2{\mathrm{\τ}}_{\mathrm{\α}}+0.25{\mathrm{\τ}}_m};\\ {\mathrm{\σ}}_m=\frac{{\mathrm{\σ}}_{\max }+{\mathrm{\σ}}_{\min }}{2},{\mathrm{\σ}}_a=\frac{{\mathrm{\σ}}_{\max }-{\mathrm{\σ}}_{\min }}{2},{\mathrm{\τ}}_m=\frac{{\mathrm{\τ}}_{\max }+{\mathrm{\τ}}_{\min }}{2},{\mathrm{\τ}}_a=\frac{{\mathrm{\τ}}_{\max }-{\mathrm{\τ}}_{\min }}{2};\\ {\mathrm{\σ}}_{\max }=\frac{F_{x1}{e}^{f^{\′}\mathrm{\π}}}{\left(e^{f^{\′}\mathrm{\π}}-1\right)A}+E\frac{b}{2R},{\mathrm{\σ}}_{\min }=\frac{F_{x1}}{\left(e^{f^{\′}\mathrm{\π}}-1\right)A};\\ {\mathrm{\τ}}_{\max }=G\frac{b\mathrm{\φ}}{l},{\mathrm{\τ}}_{\min }=-G\frac{b\mathrm{\φ}}{l}\end{array}---\left(8\right)$

Wherein, σ _bfor the tensile strength of sawing workpieces material, A is the cross-sectional area of bands for band matrix, and E is the elastic modelling quantity of sawing workpieces material, G is the coefficient of rigidity of bands for band matrix material, b is the width of bands for band, and φ is the windup-degree of bands for band, and l is the length between bands for band torsional zones;

1.3 control systems are the built-in sawing force of different sawing material and the list of centripetal force ratio k in advance, and selected by the man-machine interface of host computer and set this ratio, control system is according to centripetal force upper limit F _zmaxcalculate the nominal sawing force F of bands for band _x2=kF _zmax;

1.4 control systems are to above-mentioned specified sawing force F _x0, theoretical sawing force F _x1and nominal sawing force F _x2numerical values recited compare, reference saw shear force F _xcfor minimum of a value wherein, i.e. F _xc=min{F _x0, F _x1, F _x2, and using its control benchmark as the permanent sawing force of band sawing machine;

2.0 secondly, and slave computer accepts and sets reference saw shear force F _xc, and the flow curve data of feeding flow valve based on feed system, set and regulate the initial opening of feeding flow valve;

3.0 again, and in sawing process, power sensor records the power output of mair motor in sawing process, according to the relation of the power of mair motor, rotating speed and Initiative saw wheel moment of torsion, calculates real-time torque value in sawing process, real-time torque value is converted to real-time sawing force F _x(t) and with reference saw shear force F _xccompare, after the inner pid algorithm process of slave computer, export controlled quentity controlled variable and pass to feeding flow valve control motor, make its aperture adjusting adjust flux valve to regulate the feed speed of feed cylinder, make reference saw shear force F _xcremain stable, finally realize sawing force constant.

Further, if the formula in 1.2 (C) does not meet, then theoretical sawing force F is progressively reduced _x1numerical value turns down the tensile force F of tensioning hydro-cylinder after formula (C) is just met _pmake itself and the theoretical sawing force F reduced _x1match, formula (B) is also met, now theoretical sawing force F _x1both the requirement that formula (B) also meets formula (C) should be met.

Further, the permanent saw cutting speed control method of band sawing machine comprises the steps:

(1) selected by the man-machine interface of host computer and set corresponding sawing material, according to the sawing material of setting, choosing suitable setting saw cutting speed v from the list that control system is built-in _s;

(2) band sawing machine is first to set saw cutting speed v _sstart working, in sawing process, the actual saw cutting speed v that rotary encoder records by slave computer _sfwith the saw cutting speed v of setting _scompare, after the inner pid algorithm process of program of lower computer, export controlled quentity controlled variable to frequency converter, the rotating speed of frequency converter accommodation zone sawing machine mair motor, thus the actual saw cutting speed v of accommodation zone saw blade _sf, finally make actual saw cutting speed v _sftrend and setting saw cutting speed v _sequal.

The present invention also comprises the intelligent band sawing machine of the control method of the band sawing machine invariable power sawing described in utilization, and saw frame is arranged on band sawing machine by column, and does moving up and down of vertical direction along column; Feed cylinder drives saw frame to move in the vertical direction; Initiative saw wheel and driven saw wheel are arranged on saw frame, and both are surrounded with bands for band; Tensioning hydro-cylinder is fixed on saw frame and drives driven saw wheel to move left and right, thus the tensioning degree of accommodation zone saw blade; Mair motor is fixed on saw frame, Initiative saw wheel is driven to rotate by deceleration device, thus drive bands for band motion, sensor setting on tensioning hydro-cylinder for measuring the tensile force of tensioning hydro-cylinder, workpiece sensing bar to be arranged on saw frame with saw frame oscilaltion for detecting the height of workpiece, slave computer is by regulating the current value of mair motor thus regulating mair motor rotating speed size after D/A modular converter and frequency converter, rotary encoder is arranged in the rotating shaft of driven saw wheel, detects the rotating speed of driven saw wheel in real time; Power sensor detects frequency converter feedback current size, and by being transferred to slave computer after rotary encoder; Slave computer, by the rotating speed of mair motor that collects and torque data, based on closed-loop control, by the aperture of feeding flow valve control motor adjustment feeding flow valve, changes the rising or falling speed of feed cylinder piston rod.

Further, saw frame system also comprises electricity liquid ratio relief valve; Slave computer is by the size of current of adjustment adjustment electricity liquid ratio relief valve, and sensor-based feedback, realizes the tensile force control of tensioning hydro-cylinder; Feeding displacement transducer can detect the feeding displacement of saw frame in real time.

Further, hydraulic pump is connected with tensioning reversal valve, feed reverse valve and the oil-in that clamps reversal valve respectively, electricity liquid ratio relief valve is serially connected on the conduit under fluid pressure that tensioning reversal valve is connected with hydraulic tensioning cylinder, feeding flow valve is arranged on the conduit under fluid pressure of feed reverse valve oil return box, and the conduit under fluid pressure of tensioning reversal valve and clamping reversal valve is directly connected with fuel tank.

Further, clamping device comprises clamping device, clamping displacement transducer and clamping oil cylinder; Clamping displacement transducer is connected with the left and right chuck of clamping device, and the left chuck of clamping device or right chuck can realize the clamping to workpiece by clamping oil cylinder, are automatically recorded the distance of left and right chuck after having clamped by clamping displacement transducer.

Further, tensioning reversal valve, feed reverse valve and clamping reversal valve are respectively three position four-way electromagnetic valve.

Compared with prior art, the control method of band sawing machine invariable power of the present invention sawing and the advantage of intelligent band sawing machine thereof are:

(1) power driving mair motor is made full use of, consider the sawing operating mode limiting case on the impact of blade life and different materials feeding drag, reference saw shear force is set, based on closed-loop control, make band sawing machine saw cutting system mair motor actual use power invariability and be able to maximum using, thus achieving the sawing of band sawing machine intelligence;

(2) according to material, the physical dimension of practical work piece, the sawing tensile force that Lookup protocol is suitable, thus effectively extend the fatigue life of saw blade;

(3) by compared with the sawing force that is subject to direct-detection bands for band, the present invention is by the indirect detection of band sawing machine mair motor output torque, achieve the non-contact detecting of sawing process bands for band sawing force, not only reduce production cost, and improve the reliability of product.

Accompanying drawing explanation

Fig. 1 is the organization plan schematic diagram of a preferred embodiment of the present invention;

Fig. 2 is the control principle schematic diagram of Fig. 1;

Fig. 3 is permanent saw cutting speed control principle schematic diagram of the present invention;

Fig. 4 is bands for band mechanical model schematic diagram in normal operation;

Fig. 5 is permanent sawing force control principle schematic diagram of the present invention.

Detailed description of the invention

In order to make technical problem to be solved by this invention, technical scheme and beneficial effect clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

Please refer to shown in Fig. 1, the control method of band sawing machine invariable power of the present invention sawing and the preferred embodiment of intelligent band sawing machine thereof, comprise control system 1, saw frame system 2, feed system 3 and clamping device 4.

Control system 1 comprises the host computer 11 with man-machine interface (HMI), the slave computer 12 with Programmable Logic Controller (PLC), D/A modular converter 13, frequency converter 14, mair motor 15, power sensor 16, rotary encoder 17 and deceleration device 18.

Saw frame system 2 comprises saw frame 21, Initiative saw wheel 22, driven saw wheel 23, bands for band 24, tensioning hydro-cylinder 25, sensor 26, workpiece sensing bar 27 and electricity liquid ratio relief valve 28.

Feed system 3 comprises feed cylinder 31, feeding flow valve 32, feeding flow valve control motor 33, hydraulic pump 34, feeding displacement transducer 35, tensioning reversal valve 36, feed reverse valve 37, clamping reversal valve 38, fuel tank 39 and overflow valve 3A.

Clamping device 4 comprises clamping device 41, clamping displacement transducer 42 and clamping oil cylinder 43.Clamping displacement transducer 42 is connected with the left and right chuck of clamping device 41, the left chuck of clamping device 41 or right chuck can realize the clamping to workpiece by clamping oil cylinder 43, are automatically recorded the distance of left and right chuck after having clamped by clamping displacement transducer 42.During band sawing machine work, the clamping device 41 of clamping device 4 clamps sawing workpieces, and clamping displacement transducer 42 measures the Breadth Maximum of sawing workpieces automatically.

Saw frame 21 is arranged on band sawing machine by column, and does moving up and down of vertical direction along column.Piston rod one end of feed cylinder 31 is connected with band sawing machine base, and the other end is connected on saw frame 21, drives saw frame 21 to move in the vertical direction.Initiative saw wheel 22 and driven saw wheel 23 are arranged on saw frame 21, and both are surrounded with bands for band 24.Tensioning hydro-cylinder 25 is fixed on saw frame 21 and drives driven saw wheel 23 to move left and right, thus the tensioning degree of accommodation zone saw blade 24.Mair motor 15 is fixed on saw frame 21, drives Initiative saw wheel 22 to rotate by deceleration device 18, thus drives bands for band 24 to move.Sensor 26 is arranged on tensioning hydro-cylinder 25 for measuring the tensile force of tensioning hydro-cylinder 25 piston rod, workpiece sensing bar 27 to be arranged on saw frame 21 with saw frame 21 oscilaltion for detecting the height of workpiece, and slave computer 12 is by regulating the rotating speed size of mair motor 15 after D/A modular converter 13 and frequency converter 14.

Rotary encoder 17 is arranged in the rotating shaft of driven saw wheel 23, detects the rotating speed of driven saw wheel 23 in real time, thus by the saw cutting speed recording bands for band 24 that converts.Power sensor 16 detects the power output size of mair motor 15, and is transferred to slave computer 12, calculates corresponding torque value.Slave computer 12 is by the rotating speed of mair motor 15 that gathers and calculate and torque data, based on closed-loop control, adjusted the aperture of feeding flow valve 32 by feeding flow valve control motor 33, change the rising or falling speed of feed cylinder 31 piston rod, thus the sawing force size of adjustment belt saw blade.

Slave computer 12 is by the size of current of adjustment electricity liquid ratio relief valve 28, and based on the feedback of sensor 26, the tensile force realizing tensioning hydro-cylinder 25 controls.Feeding displacement transducer 35 can detect the feeding displacement of saw frame 21 in real time, can be converted into feed speed simultaneously, controls the maximum feed speed that feed speed is no more than setting, to avoid the too fast flutter caused of feed speed.

Hydraulic pump 34 is connected with tensioning reversal valve 36, feed reverse valve 37 and the oil-in that clamps reversal valve 38 respectively, electricity liquid ratio relief valve 28 is serially connected on the conduit under fluid pressure that tensioning reversal valve 36 is connected with tensioning hydro-cylinder 25, feeding flow valve 32 is arranged on the conduit under fluid pressure of feed reverse valve 37 oil return box 39, and the conduit under fluid pressure of tensioning reversal valve 36 and clamping reversal valve 38 is directly connected with fuel tank 39.

Tensioning reversal valve 36, feed reverse valve 37 and clamping reversal valve 38 are respectively three position four-way electromagnetic valve.

Please refer to shown in Fig. 2, control principle schematic diagram of the present invention.Be connected by connection between host computer (HMI) 11 with slave computer (PLC) 12.In the present invention, the input signal of band sawing machine comprises: saw wheel tach signal, limit signal, feed speed signal, tensile force signal and width of the workpiece signal.Wherein, the torque signal of mair motor 15 is detected by power sensor 16, and is calculated by slave computer 12.Saw wheel tach signal enters into slave computer 12 after rotary encoder 17 and input interface.Feed speed signal enters into slave computer 12 after feeding displacement transducer 35 and input interface.Limit switch is arranged on shift position saw frame 21 limiting workpiece sensing bar 27, and its limit signal is also by entering into slave computer 12 after input interface.The tensile force signal of the tensile force size of reflection tensioning hydro-cylinder 25 piston rod enters into slave computer 12 by sensor 26.Width of the workpiece signal enters into slave computer 12 after being detected by clamping displacement transducer 42.Slave computer 12 regulates the saw cutting speed of mair motor 15 by D/A modular converter 13 and frequency converter 14.Slave computer 12 controls auxiliary reclay, feeding flow valve control motor 33 and electricity liquid ratio relief valve 28 respectively by output interface.Auxiliary reclay is by magnetic valve and the contactor sawing operation of control cincture sawing machine and the opening and closing of hydraulic pump, coolant pump and feeding motor etc. respectively.Feeding flow valve control motor 33 is by controlling the aperture of feeding flow valve 32 thus the feed speed of accommodation zone sawing machine.Slave computer 12, by changing the current value of electricity liquid ratio relief valve 28, adjusts the pressure of electricity liquid ratio relief valve 28, thus regulates the tensile force of tensioning hydro-cylinder 25.

Intelligence band sawing machine carries out band sawing machine invariable power SAWING CONTROL method, comprises the permanent sawing force control method allowing the saw cutting speed of band sawing machine keep constant permanent saw cutting speed control method and to allow the sawing force of band sawing machine remain constant.

Shown in Fig. 1 and Fig. 3, the permanent saw cutting speed control method of band sawing machine comprises the steps:

(1) control system 1 built-in sawing material number and corresponding setting saw cutting speed (but being not limited to table 1) as shown in table 1.Selected by the man-machine interface of host computer 11 and set corresponding sawing material, according to the sawing material of setting, choosing suitable setting saw cutting speed v from the list that control system 1 is built-in _s.

Selecting of table 1 bands for band saw cutting speed

(2) band sawing machine is first to set saw cutting speed v _sstart working.In sawing process, the actual saw cutting speed v that rotary encoder 17 records by slave computer 12 _sfwith the saw cutting speed v of setting _scompare, after the inner pid algorithm process of slave computer 12 program, export controlled quentity controlled variable to frequency converter 14; The rotating speed of frequency converter 14 accommodation zone sawing machine mair motor 15, thus the actual saw cutting speed v of accommodation zone saw blade 24 _sf, finally make actual saw cutting speed v _sftrend and setting saw cutting speed v _sequal.

(3) when the disturbed momentum effects of mair motor 15 makes rotating speed change, also actual saw cutting speed v can be allowed by above-mentioned steps _sftrend and setting saw cutting speed v _sequal.

In the present invention, reference saw shear force F is introduced _xcconcept, reference saw shear force F _xcas the control benchmark of the permanent sawing force of band sawing machine.Reference saw shear force F _xcdrawn by following theory and experiment conclusion.

First, control system 1 calculates specified sawing force F according to the rated power of mair motor 15 according to formula (1) _x0:

$F_{x0}=\frac{P\·\mathrm{\η}}{v_s}---\left(1\right)$

In formula, P is the rated power of mair motor, and η is mechanical efficiency, v _sfor setting saw cutting speed.Setting saw cutting speed v _schanging according to the difference of workpiece material, is empirical data, selects according to table 1.Formula (1)=formula (A).

Secondly, please refer to shown in Fig. 4, bands for band 24 mechanical model in normal operation of saw frame system 2, the sawing force F of band sawing machine _xthe tensile force F of (or claiming sawing drag) and tensioning hydro-cylinder 25 _pand the relevant parameter of saw frame system 2 is correlated with and meets following formula (2).Because centripetal force F _z(or claiming feeding drag) is to tensile force F _pimpact less, usually first do not consider when sawing process mechanical modeling.Therefore, the sawing force F under this mechanical model is drawn _xmeet following formula:

$F_x=F_2-F_1=\frac{F_p(L_0+\mathrm{\π}R)(e^{f^{\′}\mathrm{\π}}-1)}{L_0(1.5+0.5e^{f^{\′}\mathrm{\π}})+R(\mathrm{\π}+\frac{e^{f^{\′}\mathrm{\π}}-1}{f^{\′}})}---\left(2\right)$

In formula, L ₀for the centre-to-centre spacing of driven wheel, R is driven wheel radius, wherein f is the confficient of static friction of bands for band and driven wheel, n _xfor the tensioning allowance factor.

At known tensile force F _pand under the condition of the relevant parameter of saw frame system 2, calculate theoretical sawing force F according to formula (2) _x1for:

$F_{x1}=\frac{F_p(L_0+\mathrm{\π}R)(e^{f^{\′}\mathrm{\π}}-1)}{L_0(1.5+0.5e^{f^{\′}\mathrm{\π}})+R(\mathrm{\π}+\frac{e^{f^{\′}\mathrm{\π}}-1}{f^{\′}})}---\left(3\right)$

Formula (3)=formula (B).

But when determining the maximum sawing force of bands for band, not directly the maximum tension power of tensioning hydro-cylinder 25 is substituted into formula (2) to carry out calculating and obtain, also must consider and checking the fatigue strength n of bands for band _{σ τ}.Band sawing machine could normal work under the condition meeting its fatigue strength requirement for bands for band 24.

In the present invention, experimentally study known, the sawing force F of band sawing machine _xthe fatigue strength n of the bands for band of formula (4) should be met _{σ τ}calculation formulas could normal work:

$n_{\mathrm{\σ}\mathrm{\τ}}=\frac{n_{\mathrm{\σ}}\·n_{\mathrm{\τ}}}{\sqrt{n_{\mathrm{\σ}}^2+n_{\mathrm{\τ}}^2}}\≥n_f---\left(4\right)$

In formula, n _f(≤1) be fatigue safety factor, usually get n _f=1.1;

$n_{\mathrm{\σ}}=\frac{0.28{\mathrm{\σ}}_b}{1.2{\mathrm{\σ}}_a+0.3{\mathrm{\σ}}_m},n_{\mathrm{\τ}}=\frac{0.23{\mathrm{\σ}}_b}{1.2{\mathrm{\τ}}_{\mathrm{\α}}+0.25{\mathrm{\τ}}_m}---\left(5\right)$

${\mathrm{\σ}}_m=\frac{{\mathrm{\σ}}_{max}+{\mathrm{\σ}}_{min}}{2},{\mathrm{\σ}}_a=\frac{{\mathrm{\σ}}_{max}-{\mathrm{\σ}}_{min}}{2},{\mathrm{\τ}}_m=\frac{{\mathrm{\τ}}_{max}+{\mathrm{\τ}}_{min}}{2},{\mathrm{\τ}}_a=\frac{{\mathrm{\τ}}_{max}-{\mathrm{\τ}}_{min}}{2}---\left(6\right)$

${\mathrm{\σ}}_{max}=\frac{F_x{e}^{f^{\′}\mathrm{\π}}}{(e^{f^{\′}\mathrm{\π}}-1)A}+E\frac{b}{2R},{\mathrm{\σ}}_{min}=\frac{F_x}{(e^{f^{\′}\mathrm{\π}}-1)A}---\left(7\right)$

${\mathrm{\τ}}_{max}=G\frac{b\mathrm{\φ}}{l},{\mathrm{\τ}}_{min}=-G\frac{b\mathrm{\φ}}{l}---\left(8\right)$

Wherein, σ _bfor the tensile strength of sawing workpieces material, A is the cross-sectional area of bands for band matrix, and E is the elastic modelling quantity of sawing workpieces material, G is the coefficient of rigidity of bands for band matrix material, b is the width of bands for band, and φ is the windup-degree of bands for band, and l is the length between bands for band torsional zones.

Use F _x1replace F _xin substitution formula (7), thus formula (4)=formula (C).

If formula (4) meets, then the tensile force of tensioning hydro-cylinder 25 continues to keep F _p.If formula (4) does not meet, then progressively reduce theoretical sawing force F _x1numerical value turns down the tensile force F of tensioning hydro-cylinder 25 after formula (4) is just met _pmake itself and the theoretical sawing force F reduced _x1match, formula (3) also meets.Therefore, now theoretical sawing force F _x1both the requirement that formula (3) also meets formula (4) should be met.

On the other hand, except considering sawing force F _xby the restriction of bands for band 24 fatigue strength, also centripetal force F must be considered _zto sawing force F _ximpact.In actual sawing process, the centripetal force F of saw frame 21 _zdetermined by the deadweight of saw frame system 2 and the pressure differential of feed cylinder 31.For some superhard material, even if saw frame centripetal force F _zreach by saw frame system 2 conduct oneself with dignity and feed cylinder 31 pressure differential determine upper limit F _zmax, the maximum sawing force F of sawing process _xmaxall the time the theoretical sawing force F of above-mentioned calculating cannot be reached _x0or F _x1, this will cause controlling to lose efficacy.Experimentally study known, the sawing force F that workpiece material is suitable _xwith centripetal force F _zbetween ratio k different and different according to material, and meet following formula:

F _x＝kF _z(9)

Therefore, according to saw frame 21 centripetal force upper limit F _zmaxthe nominal sawing force F of bands for band 24 is calculated according to formula (9) _x2=kF _zmax.

In slave computer 12 according to above-mentioned steps and formula to sawing force F _xcarry out setting and computing, draw specified sawing force F respectively _x0, theoretical sawing force F _x1and nominal sawing force F _x2.Slave computer 12 is selected the numerical values recited of these three sawing force and is judged, reference saw shear force F _xcfor minimum of a value wherein, i.e. F _xc=min{F _x0, F _x1, F _x2.Control system 1 will with reference saw shear force F _xcfor the control benchmark of the permanent sawing force of band sawing machine carries out regulation and control to equipment.Control system 1 real-time tracking reference saw shear force F _xcchange, Real-time Feedback make suitable adjustment is in time carried out to this change.

Shown in Fig. 1 and Fig. 5, according to above-mentioned theory and mechanical model, the permanent sawing force control method of band sawing machine of the present invention comprises the steps:

1.0 first, chooses the reference saw shear force F of bands for band 24 according to following methods _xc:

1.1 control systems 1 calculate specified sawing force F according to the motor rated power of mair motor 15 according to formula (1) _x0.

1.2 based on the tensile force F of tensioning hydro-cylinder 25 _pand the interrelated geometrical parameters of saw frame system 2, control system 1 calculates the theoretical sawing force F of bands for band 24 according to formula (3) _x1and Fatigue Parameter checking computations are carried out to it and judges, until theoretical sawing force F _x1both the requirement that formula (3) also meets formula (4) had been met.As satisfied tired requirement, then slave computer 12 is based on the feedback of sensor 26, and based on local closed loop pid algorithm, by changing the current value of electricity liquid ratio relief valve 28, the pressure of adjustment electricity liquid ratio relief valve 28, makes the tensile force of tensioning apparatus 25 reach and keep and F _pequal; If do not meet tired requirement, then based on fatigue condition, reduce theoretical sawing force F _x1numerical value also recalculates and revised theory sawing force F _x1make it just meet tired requirement, by changing the current value of electricity liquid ratio relief valve 28, the pressure of adjustment electricity liquid ratio relief valve 28, makes the tensile force of tensioning apparatus 25 reach and keeps and F _pequal.

1.3 also will consider centripetal force F simultaneously _zto sawing force F _ximpact.The sawing force F of the built-in different sawing material of control system 1 _xwith centripetal force F _zthe list of ratio k, is selected by the man-machine interface of host computer 11 and sets corresponding ratio k.According to the centripetal force upper limit F of saw frame 21 _zmaxthe nominal sawing force F of bands for band 24 is calculated according to formula (9) _x2.

1.4 slave computers 12 are to the specified sawing force F drawn _x0, theoretical sawing force F _x1and nominal sawing force F _x2numerical values recited carry out selecting and judging, reference saw shear force F _xcfor minimum of a value wherein, i.e. F _xc=min{F _x0, F _x1, F _x2.

2.0 secondly, and when not touching workpiece, band saw machine 21 is with the feed speed v of initial setting _a0descending.When workpiece sensing bar 27 detects that bands for band 24 is about to touch workpiece, slave computer 12 accepts and sets reference saw shear force F _xc, based on the flow curve data of the feeding flow valve 32 of feed system 3, set and regulate the initial opening of feeding flow valve 32.

3.0 again, and in sawing process, the change of material section makes sawing force F _xthere is real-time change in (t), the power output of mair motor 15 in sawing process is recorded by power sensor 16, according to the power of mair motor 15 and the relation of rotating speed and Initiative saw wheel 22 moment of torsion, calculate real-time torque value in sawing process, real-time torque value is converted to real-time sawing force F _x(t) and reference saw shear force F _xccompare, after the inner pid algorithm process of slave computer 12, export controlled quentity controlled variable and pass to feeding flow valve control motor 33, feeding flow valve control motor 33 rotates, by the feed speed regulating the aperture of feeding flow valve 32 to regulate feed cylinder 31, make reference saw shear force F _xcremain stable, finally realize sawing force constant.

The present invention overcomes the defect of prior art, is choosing reference saw shear force F _xctime taken into full account the rated power of mair motor 15, the tensile force F of tensioning hydro-cylinder 25 _p, sawing workpieces properties of materials, bands for band 24 self the various influence factor on sawing force and the impact each other thereof such as fatigue strength and saw cutting speed, choosing method is scientific and reasonable, and obtains abundant verification experimental verification.Band sawing machine of the present invention, under the condition of fatigue strength meeting bands for band 24, makes full use of the effective power of mair motor 15, realizes feed speed and the processing of saw cutting speed optimization to greatest extent, realizes the sawing of band sawing machine intelligence, improves cutting-rate.On the other hand, band sawing machine of the present invention, without the need to considering the transverse shape of workpiece, according to the difference of workpiece material and sawing operating mode, chooses reference saw shear force F automatically real-time intelligently _xc, thus meeting cutting-rate when maximizing, the service life of greatly elongated strap saw blade, cost-saving again.

Completed the constant control of saw cutting speed constant control to band sawing machine and sawing force by aforesaid operations step, thus make bands for band keep Cutting power constant in whole sawing process, improve the cutting-rate of band sawing machine and the service life of bands for band.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.

Claims (8)

1. a control method for band sawing machine invariable power sawing, described band sawing machine comprises control system (1), saw frame system (2), feed system (3) and clamping device (4), described control system (1) comprises the host computer (11) with man-machine interface, there is the slave computer (12) of Programmable Logic Controller, D/A modular converter (13), frequency converter (14), mair motor (15), power sensor (16), rotary encoder (17) and deceleration device (18), described saw frame system (2) comprises saw frame (21), Initiative saw wheel (22), driven saw wheel (23), bands for band (24), tensioning hydro-cylinder (25), sensor (26) and workpiece sensing bar (27), described feed system (3) comprises feed cylinder (31), feeding flow valve (32), feeding flow valve control motor (33), hydraulic pump (34), feeding displacement transducer (35), tensioning reversal valve (36), feed reverse valve (37), clamping reversal valve (38) and fuel tank (39), it is characterized in that, the control method of described band sawing machine invariable power sawing comprises the permanent sawing force control method of band sawing machine allowing the saw cutting speed of band sawing machine keep the constant permanent saw cutting speed control method of band sawing machine and to allow the sawing force of band sawing machine remain constant, and the permanent sawing force control method of described band sawing machine comprises the steps:

1.0 first, chooses the reference saw shear force F of bands for band (24) according to following methods _xc:

1.1 control systems (1) calculate specified sawing force F according to the rated power of mair motor (15) according to formula (A) _x0:

In formula, P is the rated power of mair motor (15); η is mechanical efficiency, v _sfor setting saw cutting speed; Setting saw cutting speed v _schanging according to the difference of workpiece material, is empirical data;

1.2 control systems (1) are according to the tensile force F of tensioning hydro-cylinder (25) _ptheoretical sawing force F is calculated according to formula (B) _x1and adopt formula (C) to carry out bands for band fatigue strength n _{σ τ}checking computations, make theoretical sawing force F _x1both meet formula (B) and also meet formula (C):

In formula, L ₀for the centre-to-centre spacing of driven wheel; R is driven wheel radius; wherein f is the confficient of static friction of bands for band and driven wheel, n _xfor the tensioning allowance factor;

In formula, n _f(≤1) be fatigue safety factor, usually get n _f=1.1;

Wherein, σ _bfor the tensile strength of sawing workpieces material, A is the cross-sectional area of bands for band matrix, and E is the elastic modelling quantity of sawing workpieces material, G is the coefficient of rigidity of bands for band matrix material, b is the width of bands for band, and φ is the windup-degree of bands for band, and l is the length between bands for band torsional zones;

1.3 control systems (1) are the built-in sawing force of different sawing material and the list of centripetal force ratio k in advance, is selected and set this ratio by the man-machine interface of host computer (11), and control system (1) is according to centripetal force upper limit F _zmaxcalculate the nominal sawing force F of bands for band (24) _x2=kF _zmax;

1.4 control systems 1 are to above-mentioned specified sawing force F _x0, theoretical sawing force F _x1and nominal sawing force F _x2numerical values recited compare, described reference saw shear force F _xcfor minimum of a value wherein, i.e. F _xc=min{F _x0, F _x1, F _x2, and using its control benchmark as the permanent sawing force of band sawing machine;

2.0 secondly, and slave computer (12) accepts and sets reference saw shear force F _xc, and the flow curve data of feeding flow valve (32) based on feed system (3), set and regulate the initial opening of feeding flow valve (32);

3.0 again, in sawing process, power sensor (16) records the power output of mair motor in sawing process (15), according to the relation of the power of mair motor (15), rotating speed and Initiative saw wheel (22) moment of torsion, calculate real-time torque value in sawing process, real-time torque value is converted to real-time sawing force F _x(t) and with reference saw shear force F _xccompare, after the inner pid algorithm process of slave computer, export controlled quentity controlled variable and pass to feeding flow valve control motor (33), make it adjust and regulate the aperture of feeding flow valve (32) to regulate the feed speed of feed cylinder (31), make reference saw shear force F _xcremain stable, finally realize sawing force constant.

2. invariable power SAWING CONTROL method as claimed in claim 1, is characterized in that, if the formula in 1.2 (C) does not meet, then progressively reduce theoretical sawing force F _x1numerical value turns down the tensile force F of tensioning hydro-cylinder (25) after formula (C) is just met _pmake itself and the theoretical sawing force F reduced _x1match, formula (B) is also met, now theoretical sawing force F _x1both the requirement that formula (B) also meets formula (C) should be met.

3. invariable power SAWING CONTROL method as claimed in claim 1, is characterized in that, the permanent saw cutting speed control method of described band sawing machine comprises the steps:

(1) selected by the man-machine interface of described host computer (11) and set corresponding sawing material, according to the sawing material of setting, choosing suitable setting saw cutting speed v from the list that described control system (1) is built-in _s;

(2) band sawing machine is first to set saw cutting speed v _sstart working, in sawing process, the actual saw cutting speed v that rotary encoder (17) records by described slave computer (12) _sfwith the saw cutting speed v of setting _scompare, after the inner pid algorithm process of slave computer (12) program, export controlled quentity controlled variable to frequency converter (14), the rotating speed of described frequency converter (14) accommodation zone sawing machine mair motor (15), thus the actual saw cutting speed v of accommodation zone saw blade (24) _sf, finally make actual saw cutting speed v _sftrend and setting saw cutting speed v _sequal.

4. utilize the intelligent band sawing machine of the control method of band sawing machine invariable power as claimed in claim 1 sawing, described saw frame (21) is arranged on band sawing machine by column, and does moving up and down of vertical direction along column, described feed cylinder (31) drives saw frame (21) to move in the vertical direction, described Initiative saw wheel (22) and driven saw wheel (23) are arranged on saw frame (21), and both are surrounded with bands for band (24), described tensioning hydro-cylinder (25) is fixed on the upper driven saw wheel (23) that drives of saw frame (21) and moves left and right, thus regulates the tensioning degree of described bands for band (24), described mair motor (15) is fixed on saw frame (21), Initiative saw wheel (22) is driven to rotate by described deceleration device (18), thus drive described bands for band (24) to move, described sensor (26) is arranged on tensioning hydro-cylinder (25) for measuring the tensile force of tensioning hydro-cylinder (25), described workpiece sensing bar (27) to be arranged on saw frame (21) with saw frame (21) oscilaltion for detecting the height of workpiece, described slave computer (12) regulates the current value of mair motor (15) afterwards by D/A modular converter (13) and frequency converter (14) thus regulates mair motor (15) rotating speed size, it is characterized in that,

Described rotary encoder (17) is arranged in the rotating shaft of driven saw wheel (23), detects the rotating speed of described driven saw wheel (23) in real time; Described power sensor (16) detects frequency converter (14) feedback current size, and is transferred to slave computer (12) by after rotary encoder (17); Described slave computer (12) is by the rotating speed of mair motor (15) that collects and torque data, based on closed-loop control, by the aperture of feeding flow valve control motor (33) adjustment feeding flow valve (32), change the rising or falling speed of feed cylinder (31) piston rod.

5. utilize intelligent band sawing machine as claimed in claim 4, it is characterized in that, described saw frame system (2) also comprises electricity liquid ratio relief valve (28); Described slave computer (12) is by the size of current of adjustment electricity liquid ratio relief valve (28), and based on the feedback of described sensor (26), the tensile force realizing described tensioning hydro-cylinder (25) controls; Described feeding displacement transducer (35) can detect the feeding displacement of saw frame (21) in real time.

6. utilize intelligent band sawing machine as claimed in claim 4, it is characterized in that, described hydraulic pump (34) respectively with tensioning reversal valve (36), the oil-in of feed reverse valve (37) and clamping reversal valve (38) is connected, described electricity liquid ratio relief valve (28) is serially connected on the conduit under fluid pressure that tensioning reversal valve (36) is connected with tensioning hydro-cylinder (25), described feeding flow valve (32) is arranged on the conduit under fluid pressure of feed reverse valve (37) oil return box (39), the conduit under fluid pressure of described tensioning reversal valve (36) and clamping reversal valve (38) is directly connected with fuel tank (39).

7. utilize intelligent band sawing machine as claimed in claim 4, it is characterized in that, described clamping device (4) comprises clamping device (41), clamping displacement transducer (42) and clamping oil cylinder (43); Described clamping displacement transducer (42) is connected with the left and right chuck of clamping device (41), the left chuck of described clamping device (41) or right chuck can realize the clamping to workpiece by clamping oil cylinder (43), are automatically recorded the distance of left and right chuck after having clamped by described clamping displacement transducer (42).

8. intelligent band sawing machine as claimed in claim 4, is characterized in that, described tensioning reversal valve (36), feed reverse valve (37) and clamping reversal valve (38) are respectively three position four-way electromagnetic valve.