CN103885387A - Method for obtaining and controlling rapid feed power and energy consumption of numerical control machine tool - Google Patents

Abstract

The invention discloses a method for obtaining and controlling the rapid feed power and the energy consumption of a numerical control machine tool. The method comprises the following steps that firstly, a maximum feed speed of a feed shaft of the numerical control machine tool is set, and the feed movement power equation and feed system parameters of the feed shaft are obtained; secondly, the computational formula of the rapid feed power and the energy consumption is obtained according to the feed system parameters and the feed movement power equation; thirdly, the feed distance of the feed shaft is set, the feed distance and different maximum feed speeds are combined, combinations of the feed distance and the different maximum feed speeds are substituted into the computational formula of the rapid feed power and the energy consumption, and a rapid feed power peak and different values of energy consumption are obtained through computation; fourthly, according to the rapid feed power peak and the different values of energy consumption, the feed shaft of the numerical control machine tool is controlled according to the appropriate maximum feed speed. By the adoption of the method for obtaining and controlling the rapid feed power and the energy consumption of the numerical control machine tool, accurate rapid feed power and energy consumption can be obtained through prediction, and a computation result can be directly used for evaluation of the energy consumption and energy-saving control of the numerical control machine tool.

Description

Obtaining and control method of numerically-controlled machine fast feed power and energy consumption

Technical field

The present invention relates to a kind of Machine-Tool Control field, relate in particular to obtaining and control method of numerically-controlled machine fast feed power and energy consumption.

Background technology

Numerically-controlled machine feeding is used for the lathe positioning actions such as cutter of advancing and retreat, and can effectively reduce lathe empty stroke time, improves working (machining) efficiency.Fast feed is frequently present in machine operation process, and its energy consumption occupies certain proportion in lathe total energy consumption.Thereby in the urgent need to the modeling method of research fast feed power and energy consumption, for the consumption assessment of lathe energy and Energy Saving Control lay the first stone.

At present, aspect the modeling of lathe energy consumption, there are being some researchs both at home and abroad.Lathe military service process is divided into startup, unloaded and processing three class subprocess by the patent documentation that for example publication number is 102621932A, predicts on this basis the energy consumption of numerically-controlled machine military service process.The patent documentation that publication number is 102637014A provides a kind of method of obtaining the dynamo-electric main transmission energy efficiency of numerically-controlled machine process, for assessment of energy consumption and the efficiency of machine tooling process, and provides basis for technological parameter energy saving optimizing.Document " Lv J; Tang R; Jia S. Therblig-based energy supply modeling of computer numerical control machine tools [J]. Journal of cleaner production.2014; 65:168-177. " the power modeling method of numerical control machine feed movement is disclosed, but do not study power and the energy predicting method of fast feed.

In sum, current research mainly concentrates on the modeling of lathe entirety energy consumption, and for each motion of lathe, the energy consumption of such as main shaft rotation, spray liquid coolant, fast feed etc. does not also have ripe modeling method.Fast feed is the important composition part of machine tool motion, and power characteristic complexity comprises acceleration, constant speed and three running statuses of deceleration, relates to multiple Energy Transfer links such as servomotor, ball-screw.Do not have at present power and the energy consumption of patent to fast feed to carry out modeling, make the energy consumption assessment of fast feed be difficult to carry out.

Summary of the invention

For the above-mentioned problems in the prior art, the object of the invention is to obtain by maximum speed of feed and feeding distance the account form of fast feed power and energy consumption, and calculate fast feed power and energy consumption, thereby provide obtaining and control method of a kind of numerically-controlled machine fast feed power and energy consumption.

Obtaining and a control method of numerically-controlled machine fast feed power and energy consumption, comprises the steps:

Step 1, for a feed shaft of numerically-controlled machine, set the maximum speed of feed of this feed shaft, obtain fast feed campaign power equation and the feed system parameter of this feed shaft, feed system parameter comprises: feeding acceleration, and feeding retarded velocity and feed system equivalence are to the accelerating force of feeding motor shaft;

Step 2, obtains the computing formula of fast feed power and energy consumption according to feed system parameter and feed motion power equation, wherein the computing formula of fast feed power and energy consumption is relevant with critical feeding distance;

Step 3, the feeding distance of setting feed shaft, combines this feeding distance from different maximum speed of feed, gained is combined to the computing formula of substitution fast feed power and energy consumption, calculates the different values of fast feed power peak and energy consumption;

Step 4, according to the different values of fast feed power peak and energy consumption, controls numerically-controlled machine feed shaft with suitable maximum speed of feed fast feed, makes fast feed power peak be less than the default performance number upper limit and energy consumption reaches minimum.

After obtaining maximum speed of feed and feeding distance, can obtain the fast feed power in each moment according to the computing formula of fast feed power, thereby can know maximum fast feed power (fast feed power peak), and because the time of fast feed is known, thereby can try to achieve energy consumption, select most suitable maximum speed of feed and feeding distance according to energy consumption, make the power of numerically-controlled machine lower than preset value, and energy consumption can be minimum, realize Energy Saving Control.

In step 1, the obtain manner of feed motion power equation is:

Step 1-1, measures lathe standby power;

Step 1-2, set the interval of speed of feed, control feed shaft zero to increasing speed of feed with set interval between maximum speed of feed, carry out feed motion, and obtain the empty cutting movement power of corresponding speed of feed, obtain the feed motion power of corresponding speed of feed according to empty cutting movement power and lathe standby power;

Step 1-3, taking speed of feed as independent variable, feed motion power is dependent variable, carries out Quadratic regression polynomial analysis, obtains feed motion power equation P _fD(f _r), wherein f _rfor speed of feed.

Wherein, because lathe standby power keeps constant under different speed of feed, therefore in step 1-2, the empty cutting movement power under corresponding speed of feed is deducted to lathe standby power, obtain the corresponding feed motion power of this speed of feed.

In step 1-3, feed system parameter acquiring mode is as follows:

Step a, is obtaining after feed motion power equation, and setting power acquisition time interval △ t controls feed shaft and repeats k complete fast feed and measure, and obtains feeding acceleration a according to following computing formula _fand feeding retarded velocity d _f:

$\left\{\begin{array}{c}{a}_f=\frac{1}{k}\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\frac{f_{r\max }}{(N_i^a-1)\mathrm{\Δt}}\\ d_f=\frac{1}{k}\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\frac{f_{r\max }}{(N_i^d-1)\mathrm{\Δt}}\end{array}\right.;$

Wherein, f _rmaxfor maximum speed of feed, in the i time fast feed

for machine power rises to from standby power the number of times that gathers power peak power process,

for machine power drops to from peak power the number of times that gathers power standby power process;

Step b, obtains the accelerating force F of feed system equivalence to feeding motor shaft according to following computing formula _fa, computing formula:

$F_{\mathrm{fa}}=\frac{1000}{k}\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\frac{P_i^{\max }-P_{\mathrm{SO}}-P_{\mathrm{FD}}\left(60f_{r\max }\right)}{a_f(N_i^a-1)\mathrm{\Δt}};$

Wherein, P _sOfor lathe standby power,

be the peak power collecting in the i time fast feed, P _fD(60f _rmax) represent f _r=60f _rmaxsubstitution P _fD(f _r) gained performance number.

Wherein, dropping to steady power by peak power from boost phase again to peak power is once complete fast feed.Each measurement gathers power in order to obtain peak power, and judges whether in boost phase or decelerating phase according to gathered power.

In step a, the value of k is 3.

Wherein multiplicity easily causes error larger very little, and multiplicity is crossed the problems such as calculated amount is excessive, and complexity is higher that easily cause at most.Therefore as preferably, be 3 by k value.

Critical feeding distance L _f0computing formula be:

Wherein, critical feeding distance L _f0change along with the change of maximum speed of feed.

Because critical feeding distance is relevant with maximum speed of feed, therefore maximum speed of feed substitution computing formula can be tried to achieve to the relational expression of critical feeding distance and speed of feed.

As feeding distance L _fmeet L _f≤ L _f0time, feed power P _rFD(t) computing formula is:

$P_{\mathrm{RFD}}\left(t\right)=\left\{\begin{array}{c}{P}_{\mathrm{FD}}\left(60a_{f}t\right)+\frac{F_{\mathrm{fa}}{a}_{1}t}{1000}(0\&le;t\&le;t_{\mathrm{FDA}})\\ P_{\mathrm{FD}}(60a_f{t}_{\mathrm{FDA}}-60d_f(t-t_{\mathrm{FDA}}))(t_{\mathrm{FDA}}<t\&le;t_{\mathrm{FDA}}+t_{\mathrm{FDD}})\end{array};\right.$

Work as L _f>L _f0time, feed power P _rFD(t) computing formula is:

$P_{\mathrm{RFD}}\left(t\right)=\left\{\begin{array}{c}{P}_{\mathrm{FD}}\left({60a}_{f}t\right)+\frac{F_{\mathrm{fa}}{a}_{f}t}{1000}(0\&le;t\&le;t_{\mathrm{FDA}})\\ P_{\mathrm{FD}}\left(60f_r\right)(t_{\mathrm{FDA}}<t\&le;t_{\mathrm{FDA}}+t_{\mathrm{FDC}})\\ P_{\mathrm{FD}}(60f_r-60d_f(t-t_{\mathrm{FDA}}-t_{\mathrm{FDC}}))(t_{\mathrm{FDA}}+t_{\mathrm{FDC}}<t\&le;t_{\mathrm{FDA}}+t_{\mathrm{FDC}}+t_{\mathrm{FDD}})\end{array}\right.$

Wherein, feeding acceleration a _f, feeding retarded velocity d _fand F _fafor fixed value, accelerated motion time t _fDA, retarded motion time t _fDDand constant motion time t _fDCall change along with the change of maximum speed of feed.

Wherein, the accelerated motion time refers to that feed shaft is from static acceleration until reach the working time of maximum speed of feed, the retarded motion time refers to that feed shaft slows down from maximum speed of feed until reach static working time, and the constant motion time refers to the working time of feed shaft with maximum speed of feed constant motion.Feeding acceleration a _f, feeding retarded velocity d _fand feed system equivalence is to the accelerating force F of feeding motor shaft _fafor fixed value, after the maximum speed of feed of setting by step 1 is tried to achieve these feed system parameters, then change maximum speed of feed and ask in the process of feed power and energy consumption, these feed system parameters do not change.

Work as L _f≤ L _f0time, accelerated motion time t _fDAwith retarded motion time t _fDDcomputing formula is as follows

$\left\{\begin{array}{c}{t}_{\mathrm{FDA}}=\sqrt{\frac{{2L}_f{d}_f}{a_f(a_f+d_f)}}\\ t_{\mathrm{FDD}}=\sqrt{\frac{{2L}_f{a}_f}{d_f(a_f+d_f)}}\end{array}\right.;$

Work as L _f>L _f0time, accelerated motion time t _fDA, retarded motion time t _fDDand constant motion time t _fDCcomputing formula is as follows:

$\left\{\begin{array}{c}{t}_{\mathrm{FDA}}=\frac{f_{r\max }}{a_f}\\ t_{\mathrm{FDC}}=\frac{L_f-L_{f0}}{f_{r\max }}\\ t_{\mathrm{FDD}}=\frac{f_{r\max }}{d_f}\end{array}\right..$

Feeding is divided into two types of triangle feeding and trapezoidal feedings, classifies by calculating critical feeding distance.In the time that feeding distance is not more than critical feeding distance, there is not the time of power invariability, be triangle feeding; In the time that feeding distance is greater than critical feeding distance, there is the time of power invariability, be trapezoidal feeding.

Wherein, work as L _f≤ L _f0time, the computing formula of energy consumption is:

$E_{\mathrm{RFD}}={\&Integral;}_0^{t_{\mathrm{FDA}}+t_{\mathrm{FDD}}}{P}_{\mathrm{RFD}}\left(t\right)\mathrm{dt},$

Wherein, P _rFD(t) be L _f≤ L _f0time feed power computing formula;

Work as L _f>L _f0time, the computing formula of energy consumption is:

$E_{\mathrm{RFD}}={\&Integral;}_0^{t_{\mathrm{FDA}}+t_{\mathrm{FDC}+}{t}_{\mathrm{FDD}}}{P}_{\mathrm{RFD}}\left(t\right)\mathrm{dt},$

Wherein, P _rFD(t) be L _f>L _f0time feed power computing formula.

Because energy consumption is power about the integration of time, and in the situation that feeding distance is different from critical feeding distance relation, the computing formula difference of feed power, therefore integrand P in the computing formula of energy consumption under different feeding distances _rFD(t) be the computing formula of the feed power corresponding with feeding distance.

Method of the present invention is applicable to all feed shafts (comprising X, Y, Z axis) of dissimilar numerically-controlled machine, can be used in the fast feed power and the energy consumption that obtain single feed shaft, for the situation of the collaborative fast feed of multiaxis, only the fast feed power of each feed shaft of synchronization need be added, can obtain the collaborative fast feed power of multiaxis, the energy consumption of each feed shaft fast feed is added, can obtains the energy consumption of the collaborative fast feed of multiaxis.

The inventive method is convenient to predict numerically-controlled machine fast feed power and energy consumption, and controls accordingly, thereby reaches the object of Energy Saving Control.

Brief description of the drawings

Fig. 1 is the schematic flow sheet of the inventive method;

Fig. 2 is the machine power-time curve of the feed motion that collects of one embodiment of the invention;

Fig. 3 is the machine power-time curve of the fast feed that collects of the current embodiment of the present invention;

Fig. 4 is fast feed predicted power and the measured power comparison diagram in the current embodiment of the inventive method.

Embodiment

Now in conjunction with the embodiments and Figure of description, the present invention is carried out to detailed explanation.

One embodiment of the invention, using the Z axis of numerically controlled lathe as selected feed shaft, describes feed power and energy consumption modeling method in detail.

Wherein, the CK6153i numerically controlled lathe that selected lathe is Jinan No.1 Machine Tool Plant, the speed of feed f that Z axis is set _rmax=8m/min=133.3mm/s, feeding distance L _fbe respectively 10mm and 30mm.

The numerically-controlled machine fast feed power of the current embodiment of the present invention and energy consumption obtain and control method as shown in Figure 1, comprise the steps:

Step 1, in numerically-controlled machine, select the feed shaft of a needs control, set the maximum speed of feed of this feed shaft, obtain feed motion power equation and the feed system parameter of this feed shaft, feed system parameter comprises: feeding acceleration, feeding retarded velocity and feed system equivalence are to the accelerating force of feeding motor shaft.

Step 1-1, measures lathe standby power P _sO.

Power data harvester is connected in to lathe power input, measures lathe standby power P _sO=328.1W.

Step 1-2, set the interval of speed of feed, control feed shaft zero to increasing speed of feed with set interval between maximum speed of feed, carry out feed motion, and obtain the empty cutting movement power of corresponding speed of feed, obtain the feed motion power of corresponding speed of feed according to empty cutting movement power and lathe standby power.

Control Z axis, 0 between maximum speed of feed taking 200mm/min as incremental spacing, make feed shaft do feed motion with different speed of feed, measurement gained machine power-time curve as shown in Figure 2.Power during by feed motion deducts lathe standby power P _sO, the feed motion power that obtains corresponding speed of feed is as shown in table 1:

Table 1

Step 1-3, taking speed of feed as independent variable, feed power is dependent variable, carries out Quadratic regression polynomial analysis, obtains feed motion power equation P _fD(f _r).

Taking speed of feed as independent variable, feed motion power is dependent variable, does Quadratic regression polynomial analysis, obtains feed motion power equation:

P _FD(f)=2×10 ^-6f _r ²+0.0311f _r (1)

Wherein, P _fD(f _r) be feed motion power, unit is watt (W); f _rbe speed of feed, unit is mm/min (mm/min).

Obtain feed motion power equation P _fD(f _r) after, obtain feed system parameter, concrete mode is as follows:

Step a, setting power acquisition time interval △ t, controls feed shaft and repeats k complete fast feed and measure, and obtains feeding acceleration a according to following computing formula _fand feeding retarded velocity d _f.

Wherein k value is 3, controls Z axis and carries out 3 complete fast feed, and setting power acquisition interval time △ t=0.02s, measures the machine power-time curve of feeding, as shown in Figure 3.

In the i time fast feed, machine power rises to from standby power the number of times that gathers power peak power process

machine power drops to from peak power the number of times that gathers power standby power process

and the lathe peak power of measuring for the i time

as shown in table 2:

Table 2

Calculate a _fand d _f:

$\left\{\begin{array}{c}{a}_f=\frac{1}{3}\underset{i=1}{\overset{3}{\mathrm{\&Sigma;}}}\frac{f_{r\max }}{(N_i^a-1)\mathrm{\&Delta;t}}=1058(\mathrm{mm}/s^2)\\ d_f=\frac{1}{3}\underset{i=1}{\overset{3}{\mathrm{\&Sigma;}}}\frac{f_{r\max }}{(N_i^d-1)\mathrm{\&Delta;t}}=1740\left({\mathrm{mm}/s}^2\right)\end{array}\right.---\left(2\right)$

Thereby, calculate F _fa:

$F_{\mathrm{fa}}=\frac{1000}{3}\underset{i=1}{\overset{3}{\mathrm{\&Sigma;}}}\frac{P_i^{\max }-P_{\mathrm{SO}}-P_{\mathrm{FD}}\left(60f_{r\max }\right)}{a_f(N_i^a-1)\mathrm{\&Delta;t}}=5604\left(N\right)---\left(3\right)$ Step 2, obtains the computing formula of fast feed power and energy consumption according to feed system parameter and feed motion power equation.

Wherein, the computing formula of fast feed power and energy consumption is relevant with critical feeding distance, and critical feeding distance computing formula is:

${\mathrm{<figure-callout\; id="0"\; label="L\; f"\; filenames="HDA0000474595320000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_f=\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; r\; max"\; filenames="HDA0000474595320000012.png"\; state="\{\{state\}\}">f</figure-callout>}}_{r\max }^{}}{{2a}_f}+\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; r\; max"\; filenames="HDA0000474595320000012.png"\; state="\{\{state\}\}">f</figure-callout>}}_{r\max }^{}}{{2d}_f}---\left(4\right)$

Work as L _f≤ L _f0time, feed power P _rFDcomputing formula be:

$P_{\mathrm{RFD}}\left(t\right)=\left\{\begin{array}{c}{P}_{\mathrm{FD}}\left(60a_{f}t\right)+\frac{F_{\mathrm{fa}}{a}_{1}t}{1000}(0\&le;t\&le;t_{\mathrm{FDA}})\\ P_{\mathrm{FD}}(60a_f{t}_{\mathrm{FDA}}-60d_f(t-t_{\mathrm{FDA}}))(t_{\mathrm{FDA}}<t\&le;t_{\mathrm{FDA}}+t_{\mathrm{FDD}})\end{array};\right.$

Thereby obtain:

$E_{\mathrm{RFD}}={\&Integral;}_0^{t_{\mathrm{FDA}}+t_{\mathrm{FDD}}}{P}_{\mathrm{RFD}}\left(t\right)\mathrm{dt}---\left(5\right)$

Accelerated motion time t _fDAwith retarded motion time t _fDDcomputing formula is as follows:

$\left\{\begin{array}{c}{t}_{\mathrm{FDA}}=\sqrt{\frac{{2L}_f{d}_f}{a_f(a_f+d_f)}}\\ t_{\mathrm{FDD}}=\sqrt{\frac{{2L}_f{a}_f}{d_f(a_f+d_f)}}\end{array}\right.---\left(6\right)$

Work as L _f>L _f0time, feed power P _rFDcomputing formula be:

$P_{\mathrm{RFD}}\left(t\right)=\left\{\begin{array}{c}{P}_{\mathrm{FD}}\left({60a}_{f}t\right)+\frac{F_{\mathrm{fa}}{a}_{f}t}{1000}(0\&le;t\&le;t_{\mathrm{FDA}})\\ P_{\mathrm{FD}}\left(60f_r\right)(t_{\mathrm{FDA}}<t\&le;t_{\mathrm{FDA}}+t_{\mathrm{FDC}})\\ P_{\mathrm{FD}}(60f_r-60d_f(t-t_{\mathrm{FDA}}-t_{\mathrm{FDC}}))(t_{\mathrm{FDA}}+t_{\mathrm{FDC}}<t\&le;t_{\mathrm{FDA}}+t_{\mathrm{FDC}}+t_{\mathrm{FDD}})\end{array}\right.---\left(7\right)$

Thereby the computing formula that obtains energy consumption is:

$E_{\mathrm{RFD}}={\&Integral;}_0^{t_{\mathrm{FDA}}+t_{\mathrm{FDC}+}{t}_{\mathrm{FDD}}}{P}_{\mathrm{RFD}}\left(t\right)\mathrm{dt}---\left(8\right)$

Wherein t _fDAfor accelerated motion time, t _fDDfor retarded motion time, t _fDCfor the constant motion time:

$\left\{\begin{array}{c}{t}_{\mathrm{FDA}}=\frac{f_{r\max }}{a_f}\\ t_{\mathrm{FDC}}=\frac{L_f-L_{f0}}{f_{r\max }}\\ t_{\mathrm{FDD}}=\frac{f_{r\max }}{d_f}\end{array}\right.---\left(9\right)$

Step 3, the feeding distance of setting feed shaft, combines this feeding distance from different speed of feed, gained is combined to the computing formula of substitution feed power and energy consumption, calculates the different values of fast feed power peak and energy consumption.

Before setting the feeding distance of feed shaft, can test, obtain fast feed power and energy consumption under different feeding distances, adopt the maximum speed of feed of setting, obtain the computing formula of feed power and the value of energy consumption.

Set maximum speed of feed, ${\mathrm{<figure-callout\; id="0"\; label="L\; f"\; filenames="HDA0000474595320000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_f=\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; r\; max"\; filenames="HDA0000474595320000012.png"\; state="\{\{state\}\}">f</figure-callout>}}_{r\max }^{}}{{2a}_f}+\frac{{\mathrm{<figure-callout\; id="2"\; label="f\; r\; max"\; filenames="HDA0000474595320000012.png"\; state="\{\{state\}\}">f</figure-callout>}}_{r\max }^{}}{{2d}_f}=13.5\left(\mathrm{mm}\right)$

As feeding distance L _f=10mm, now L _f≤ L _f0, feed power curve is triangle, accelerated motion time t _fDAwith retarded motion time t _fDDbe calculated as follows:

$\left\{\begin{array}{c}{t}_{\mathrm{FDA}}=\sqrt{\frac{{2L}_f{d}_f}{a_f(a_f+d_f)}}=0.11s\\ t_{\mathrm{FDD}}=\sqrt{\frac{{2L}_f{a}_f}{d_f(a_f+d_f)}}=0.07s\end{array}\right.$

Calculate feed power P _rFD:

$P_{\mathrm{RFD}}\left(t\right)=\left\{\begin{array}{c}8059{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000474595320000012.png"\; state="\{\{state\}\}">t</figure-callout>}}^2+7903t(0\&le;t\&le;0.11)\\ P_{\mathrm{FD}}(18466.8-104400t)(0.11<t\&le;0.18)\end{array}\right.$

Calculate energy consumption E _rFD:

$E_{\mathrm{RFD}}={\&Integral;}_0^{0.18}{P}_{\mathrm{RFD}}\left(t\right)\mathrm{dt}=55.9\left(J\right);$

As feeding distance L _f=30mm, now L _f>L _f0, feed power curve is trapezoidal, accelerated motion time t _fDA, constant motion time t _fDCwith retarded motion time t _fDDbe calculated as:

$\left\{\begin{array}{c}{t}_{\mathrm{FDA}}=\frac{f_{r\max }}{a_f}=0.13s\\ t_{\mathrm{FDC}}=\frac{L_f-L_{f0}}{f_{r\max }}=0.12s\\ t_{\mathrm{FDD}}=\frac{f_{r\max }}{d_f}=0.08\end{array}\right.;$

Calculate feed power P _rFD:

$P_{\mathrm{RFD}}\left(t\right)=\left\{\begin{array}{c}{8059\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000474595320000012.png"\; state="\{\{state\}\}">t</figure-callout>}}^2+7903t(0\&le;t\&le;0.13)\\ 376.8(0.13<t\&le;0.25)\\ P_{\mathrm{FD}}(34098-104400t)(0.25<t\&le;0.33)\end{array}\right.$

Calculate energy consumption E _rFD:

$E_{\mathrm{RFD}}={\&Integral;}_0^{0.33}{P}_{\mathrm{RFD}}\left(t\right)\mathrm{dt}=145.2\left(J\right);$

Fast feed power when testing selected lathe Z axis feeding distance and being 10mm and 30mm, and it is compared with the calculated results, as shown in Figure 4, the energy consumption predicted value and the measured value contrast that further calculate Z axis fast feed are as shown in table 3.

Table 3

Relative error=| energy consumption predicted value-energy consumption actual measurement value |/energy consumption actual measurement value × 100%

Find by above-mentioned experiment contrast, the fast feed power of application the method prediction is very identical with measured power, when feeding distance hour, the relative error of energy consumption prediction is larger, up to 23.2%, in the time that feeding distance is larger, the relative error of energy consumption prediction is very little, only has 0.76%.

For feeding same distance but set the situation of different maximum speed of feed, calculate corresponding fast feed power peak and power consumption values, selection makes fast feed power peak within the default performance number upper limit and the scheme of energy consumption minimum is carried out fast feed, realizes the Energy Saving Control of fast feed process.

Now need to adopt selected CK6153i numerical controlled lathe Z shaft to do the fast feed campaign that feeding distance is 50mm, by adjusting tool feeding multiplying power, maximum speed of feed can be set to respectively 2m/min, 4m/min and 8m/min.According to fast feed rating formula (7), energy consumption calculation formula (8) and fast feed time (accelerated motion time, retarded motion time and constant motion time) computing formula (9), T.T., feed power peak value and the energy consumption that can estimate the feeding of above-mentioned three feasible programs, result is as shown in table 4.

Table 4

If predefined power upper control limit P _u=1000W, as can be seen from Table 4, the fast feed power peak power P of scheme three _max>P _u, do not meet the demands; The fast feed power peak P of scheme one and scheme two _max<P _u, meet the demands, than scheme two, select scheme for the moment, fast feed energy consumption is less.But the time of scheme one be almost the twice of scheme two, if by lathe standby power P _sOtake into account, the lathe energy consumption of scheme one is 113.3+P _sO× 1.5=605W, the lathe energy consumption of scheme two is 129.4+P _sO× 0.8=392 W, scheme two is more energy-conservation.Comprehensive above analysis, selection scheme two is as fast feed operating scheme.

Therefore, the inventive method can obtain fast feed power and energy consumption more accurately for prediction, and result of calculation can be directly used in lathe energy consumption assessment and Energy Saving Control.

Method of the present invention is applicable to all feed shafts (comprising X, Y, Z axis) of dissimilar numerically-controlled machine, can be used in the fast feed power and the energy consumption that obtain single feed shaft, for the situation of the collaborative fast feed of multiaxis, only the fast feed power of each feed shaft of synchronization need be added, can obtain the collaborative fast feed power of multiaxis, the energy consumption of each feed shaft fast feed is added, can obtains the energy consumption of the collaborative fast feed of multiaxis.

Finally explanation is, above case study on implementation is only unrestricted in order to technical scheme of the present invention to be described, technical scheme of the present invention is modified or replaced on an equal basis, and do not depart from aim and the scope of the inventive method, it all should be encompassed in the middle of claim scope of the present invention.

Claims (8)

1. obtaining and a control method of numerically-controlled machine fast feed power and energy consumption, is characterized in that, comprises the steps:

Step 1, in numerically-controlled machine, select the feed shaft of a needs control, set the maximum speed of feed of this feed shaft, obtain feed motion power equation and the feed system parameter of this feed shaft, feed system parameter comprises: feeding acceleration, and feeding retarded velocity and feed system equivalence are to the accelerating force of feeding motor shaft;

Step 2, obtains the computing formula of fast feed power and energy consumption according to feed system parameter and feed motion power equation, wherein the computing formula of fast feed power and energy consumption is relevant with critical feeding distance;

Step 3, the feeding distance of setting feed shaft, combines this feeding distance from different maximum speed of feed, gained is combined to the computing formula of substitution fast feed power and energy consumption, calculates the different values of fast feed power peak and energy consumption;

Step 4, according to the different values of fast feed power peak and energy consumption, controls numerically-controlled machine feed shaft with suitable maximum speed of feed fast feed, makes fast feed power peak be less than the default performance number upper limit and energy consumption reaches minimum.

2. obtaining and control method of numerically-controlled machine fast feed power and energy consumption as claimed in claim 1, is characterized in that, in step 1, the obtain manner of feed motion power equation is:

Step 1-1, measures lathe standby power;

Step 1-2, set the interval of speed of feed, control feed shaft zero to increasing speed of feed with set interval between maximum speed of feed, carry out feed motion, and obtain the empty cutting movement power of corresponding speed of feed, obtain the feed motion power of corresponding speed of feed according to empty cutting movement power and lathe standby power;

Step 1-3, taking speed of feed as independent variable, feed motion power is dependent variable, carries out Quadratic regression polynomial analysis, obtains feed motion power equation P _fD(f _r), wherein f _rfor speed of feed.

3. obtaining and control method of numerically-controlled machine fast feed power and energy consumption as claimed in claim 2, is characterized in that, feed system parameter acquiring mode is as follows:

Step a, is obtaining after feed motion power equation, and setting power acquisition time interval △ t controls feed shaft and repeats k complete fast feed and measure, and obtains feeding acceleration a according to following computing formula _fand feeding retarded velocity d _f:

$\left\{\begin{array}{c}{a}_f=\frac{1}{k}\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}\frac{f_{r\max }}{(N_i^a-1)\mathrm{\&Delta;t}}\\ d_f=\frac{1}{k}\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}\frac{f_{r\max }}{(N_i^d-1)\mathrm{\&Delta;t}}\end{array}\right.;$

Wherein, f _rmaxfor maximum speed of feed, in the i time fast feed

for machine power rises to from standby power the number of times that gathers power peak power process, for machine power drops to from peak power the number of times that gathers power standby power process;

Step b, obtains the accelerating force F of feed system equivalence to feeding motor shaft according to following computing formula _fa, computing formula is:

$F_{\mathrm{fa}}=\frac{1000}{k}\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}\frac{P_i^{\max }-P_{\mathrm{SO}}-P_{\mathrm{FD}}\left(60f_{r\max }\right)}{a_f(N_i^a-1)\mathrm{\&Delta;t}};$

Wherein, P _sOfor lathe standby power,

be the peak power collecting in the i time fast feed, P _fD(60f _rmax) represent f _r=60f _rmaxsubstitution P _fD(f _r) gained performance number.

4. obtaining and control method of numerically-controlled machine fast feed power and energy consumption as claimed in claim 3, is characterized in that, in step a, the value of k is 3.

5. obtaining and control method of numerically-controlled machine fast feed power and energy consumption as claimed in claim 3, is characterized in that critical feeding distance L _f0computing formula be:

Wherein, critical feeding distance L _f0change along with the change of maximum speed of feed.

6. obtaining and control method of numerically-controlled machine fast feed power and energy consumption as claimed in claim 5, is characterized in that, as feeding distance L _fmeet L _f≤ L _f0time, feed power P _rFD(t) computing formula is:

$P_{\mathrm{RFD}}\left(t\right)=\left\{\begin{array}{c}{P}_{\mathrm{FD}}\left(60a_{f}t\right)+\frac{F_{\mathrm{fa}}{a}_{1}t}{1000}(0\&le;t\&le;t_{\mathrm{FDA}})\\ P_{\mathrm{FD}}(60a_f{t}_{\mathrm{FDA}}-60d_f(t-t_{\mathrm{FDA}}))(t_{\mathrm{FDA}}<t\&le;t_{\mathrm{FDA}}+t_{\mathrm{FDD}})\end{array};\right.$

Work as L _f>L _f0time, feed power P _rFD(t) computing formula is:

$P_{\mathrm{RFD}}\left(t\right)=\left\{\begin{array}{c}{P}_{\mathrm{FD}}\left({60a}_{f}t\right)+\frac{F_{\mathrm{fa}}{a}_{f}t}{1000}(0\&le;t\&le;t_{\mathrm{FDA}})\\ P_{\mathrm{FD}}\left(60f_r\right)(t_{\mathrm{FDA}}<t\&le;t_{\mathrm{FDA}}+t_{\mathrm{FDC}})\\ P_{\mathrm{FD}}(60f_r-60d_f(t-t_{\mathrm{FDA}}-t_{\mathrm{FDC}}))(t_{\mathrm{FDA}}+t_{\mathrm{FDC}}<t\&le;t_{\mathrm{FDA}}+t_{\mathrm{FDC}}+t_{\mathrm{FDD}})\end{array}\right.$ ，

Wherein, feeding acceleration a _f, feeding retarded velocity d _fand F _fafor fixed value, accelerated motion time t _fDA, retarded motion time t _fDDand constant motion time t _fDCall change along with the change of maximum speed of feed.

7. obtaining and control method of numerically-controlled machine fast feed power and energy consumption as claimed in claim 6, is characterized in that, works as L _f≤ L _f0time, accelerated motion time t _fDAwith retarded motion time t _fDDcomputing formula is as follows

$\left\{\begin{array}{c}{t}_{\mathrm{FDA}}=\sqrt{\frac{{2L}_f{d}_f}{a_f(a_f+d_f)}}\\ t_{\mathrm{FDD}}=\sqrt{\frac{{2L}_f{a}_f}{d_f(a_f+d_f)}}\end{array}\right.;$

Work as L _f>L _f0time, accelerated motion time t _fDA, retarded motion time t _fDDand constant motion time t _fDCcomputing formula is as follows:

$\left\{\begin{array}{c}{t}_{\mathrm{FDA}}=\frac{f_{r\max }}{a_f}\\ t_{\mathrm{FDC}}=\frac{L_f-L_{f0}}{f_{r\max }}\\ t_{\mathrm{FDD}}=\frac{f_{r\max }}{d_f}\end{array}\right..$

8. obtaining and control method of numerically-controlled machine fast feed power and energy consumption as claimed in claim 7, is characterized in that, wherein,

Work as L _f≤ L _f0time, the computing formula of energy consumption is:

$E_{\mathrm{RFD}}={\&Integral;}_0^{t_{\mathrm{FDA}}+t_{\mathrm{FDD}}}{P}_{\mathrm{RFD}}\left(t\right)\mathrm{dt},$

Wherein, P _rFD(t) be L _f≤ L _f0time fast feed rating formula;

Work as L _f>L _f0time, the computing formula of energy consumption is:

$E_{\mathrm{RFD}}={\&Integral;}_0^{t_{\mathrm{FDA}}+t_{\mathrm{FDC}+}{t}_{\mathrm{FDD}}}{P}_{\mathrm{RFD}}\left(t\right)\mathrm{dt},$

Wherein, P _rFD(t) be L _f>L _f0time fast feed rating formula.

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