CN101620435B - Speed connection method for numerical control system - Google Patents

Abstract

The invention relates to a speed connection method for a numerical control system, which comprises the following steps: performing dynamic pre-read processing on a workpiece program of the numerical control system to obtain the speed change length and the corner connection error between adjacent workpiece program segments; calculating the initial connection speed between the adjacent workpiece program segments according to the corner connection error, the programming feed speed of the workpiece program, and the processing precision required by a user; and automatically adjusting the connection speed between the adjacent workpiece program segments according to the preset maximum acceleration of each servo shaft of the numerical control system, the speed change length between the adjacent workpiece program segments and the initial connection speed between the adjacent workpiece program segments. The method greatly improves the execution efficiency of a numerical control machine tool, ensures that the connection error generated at a corner between any workpiece program segments in the moving process of the numerical control machine tool satisfies the working accuracy requirements of users, improves the control precision of the system, achieves the speed smooth transition, and can be matched with various acceleration and deceleration algorithms.

Description

A kind of speed connection method that is used for digital control system

Technical field

The present invention relates to the speed connection processing technology of numerically-controlled machine in the fields of numeric control technique, corner angle between specifically a kind of work procedure that produces according to CAD/CAM, the desired machining precision of user, each peak acceleration and regulate the speed connection method that is used for digital control system of the connection speed of corner automatically along the intersegmental rate conversion length of the processing stage of each.

Background technology

In modern manufacturing industry, the target that the processing of the high-speed, high precision of digital control system can be pursued " low consumption and high-quality fast, " for manufacturing industry provides powerful support.The high speed and super precision motion control method of digital control system is the important means that improves numerically-controlled machine working (machining) efficiency and quality, and international production engineering association (CIRP) is defined as it one of center research direction of 21 century.China has obtained important breakthrough at the main frame technical elements at present, has realized the fast moving speed of 60m/min as machining center, and main bottleneck is the high speed and super precision motion control method.Realize the control of digital control system high-speed, high precision, requirement is on the basis that guarantees the digital control system machining precision, numerically-controlled machine continues most possibly with higher speed motion, therefore the speed connection method of digital control system is for research high speed and super precision control technology, and development high speed and super precision process technology is equipped with important function and significance.

Digital control system speed connection method commonly used has accurate method of shutting down, continuous path method and accurate path method at present.Wherein, accurately method of shutting down is to stop after work procedure has moved each work procedure section, can both accurately locate to guarantee each work procedure section.This speed connection method can obtain high orientation precision, yet each work procedure section is all realized the acceleration and deceleration process one time, has reduced working (machining) efficiency; And because the frequent start-stop of system causes workpiece machining surface rough, problems such as crudy difference easily.The continuous path method is meant in order to improve the working (machining) efficiency of digital control system, in work procedure processing beginning to carry out accelerated motion, carry out retarded motion in the work procedure process finishing, in the work procedure operational process,, do not carry out acceleration and deceleration control with the programming speed of feed motion of work procedure.This speed connection method can guarantee that numerically-controlled machine all the time with the maximal rate motion, obtains higher working (machining) efficiency, yet in order to keep speed of feed, may have been reduced the machining precision of system by slight rounding at sharp corner.Accurately method implementation commonly used in path is each work procedure section all to be done acceleration and deceleration handle, and in previous work procedure section reduction of speed, introduces next work procedure section, and the aggregate velocity of two work procedure sections is as the final output speed of system.This speed connected mode is a kind of compromise processing mode between speed and precision, can guarantee that two sections speed between the work procedure section are continuous, guarantee the flatness of workpiece processing surface of the work, if yet the work procedure section in the work procedure is very short, the motion of numerically-controlled machine is difficult to reach the programming speed of feed; If one or more short work procedure sections are arranged after the long work procedure section, probably in the process than long work procedure section reduction of speed, one or more short work procedure sections are finished, cause the bigger shape error in processing work surface, be difficult to realize the optimal combination of precision and speed, even the length difference of each adjacent workpieces program segment is little in the work procedure, also be difficult to analyze the connection error between the adjacent workpieces program segment, determine to have brought uncertain factor for the digital control system machining precision.

Summary of the invention

At above shortcomings in the prior art, the technical problem to be solved in the present invention provides a kind of speed connection method that is used for digital control system, corner angle, the desired machining precision of user, each peak acceleration and the speed connection method that is used for digital control system of regulating the intersegmental corner of work procedure process velocity along the intersegmental rate conversion length of the work procedure of each automatically between its work procedure that produces according to CAD/CAM.

For solving the problems of the technologies described above, the technical solution used in the present invention is:

A kind of speed connection method that is used for digital control system of the present invention has following steps:

The digital control system work procedure is carried out dynamic pre-read processing, and the rate conversion length that obtains between the adjacent workpieces program segment is connected error with the turning;

According to the initial connect-speed between the desired machining precision calculating of programming speed of feed, the user adjacent workpieces program segment of turning connection sum of errors work procedure;

Automatically regulate connection speed between the adjacent workpieces program segment according to the rate conversion length between the peak acceleration that sets in advance each axis servomotor of digital control system, adjacent workpieces program segment and the initial connect-speed between the adjacent workpieces program segment.

Described dynamic pre-read processing may further comprise the steps:

If total line number of work procedure is n, the approximate all long l that is _Ave, it is p that the reading in advance of work procedure handled line number _n, read to handle line number in advance by what following formula calculated work procedure:

$p_n\≥\frac{n}{\mathrm{\Δt}}-\frac{l_{\mathrm{ave}}*n}{v*{\mathrm{\Δt}}^2}$ (12)

Wherein v is the programming speed of feed of work procedure, and Δ t is the digital control system interpolation cycle.

Described rate conversion length is under the condition of each axis servomotor peak acceleration of known digital control system, and digital control system is from a movement velocity v ₁Be transformed into another movement velocity v ₂The shortest required length of motion route by the peak acceleration of each axis servomotor, starting velocity, termination speed and the realization deceleration planning method that rate conversion adopted of rate conversion, is asked for corresponding rate conversion length.

It is the processing work surface configuration deviation e that the user can allow in digital control system speed connection procedure that described turning connects error, calculates by following formula:

$e\≤\frac{v*\mathrm{\Δt}*\sin \mathrm{\θ}}{\sqrt{8*(1+\cos \mathrm{\θ})}}$ (8)

Wherein v is the programming speed of feed of work procedure, and Δ t is the digital control system interpolation cycle, and θ is the intersegmental corner angle of adjacent programs.

Described calculating initial connect-speed v _LinkCalculate by following formula:

$v_{\mathrm{link}}=\min \{v,\frac{e_{\max }*\sqrt{8*(1+\cos \mathrm{\θ})}}{\mathrm{\Δt}*\sin \mathrm{\θ}}\}$ (16)

Wherein v is the programming speed of feed of work procedure, and θ is the corner angle between the adjacent workpieces program segment, and Δ t is the digital control system interpolation cycle, e _MaxThe maximum turning connection error of setting for the user is the desired minimum machining precision of user.

Connection speed between described automatic adjusting adjacent workpieces program segment may further comprise the steps:

If the first motion speed V of first program segment of work procedure _InitBe zero, establish the termination movement velocity V of last program segment in the dynamic preprocessing process _EndBe zero;

If motion is from first motion speed V _InitBe transformed into and stop movement velocity V _EndBetween required rate conversion length l _cIf the length l of＞work procedure section is and first motion speed V _Init＜termination movement velocity V _End, utilize known work procedure section operation initial velocity V _InitWith work procedure segment length l, with reference to asking for the rate conversion length l _cMethod, obtain under the situation of given length l the highest termination speed V that motion can reach from initial velocity _End', and make V _End=V _End', connection speed is regulated termination automatically.

If first motion speed V _Init＞termination movement velocity V _End, by asking for the rate conversion length l _cMethod, obtain at given length l and stop movement velocity V _EndSituation under, the motion the highest first motion speed V that can reach _Init', and make V _Init=V _Init', change the termination movement velocity V of adjacent previous work procedure section _End=V _Init', and under new termination movement velocity condition, regulate the first motion speed of adjacent previous work procedure section by the automatic regulating step of motion connection speed;

Above-mentioned steps is carried out repeatedly, regulates end condition automatically up to satisfying connection speed.

The described execution repeatedly is meant in the speed adjustment process of current work procedure section, automatically regulate end condition if can't satisfy connection speed, then trace back to its adjacent previous or preceding several work procedure sections, till satisfying connection speed and regulating end condition automatically.

If motion is from first motion speed V _InitBe transformed into and stop movement velocity V _EndBetween required rate conversion length l _cThe length l of≤work procedure section regulates stopping automatically.

The present invention has following beneficial effect and advantage:

1. carry out the efficient height.The inventive method on the basis of avoiding the data famine, has greatly improved the execution efficient of numerically-controlled machine by " dynamic pre-read processing " function.

2. machining precision height.The inventive method is introduced the notion of " turning connection error ", guarantees that the connection error of any place, the intersegmental turning of work procedure generation in the numerically-controlled machine motion process satisfies user's requirement on machining accuracy, has improved the control accuracy of system.

3. smoothness height.The inventive method adopts the method for " the intersegmental speed of work procedure is regulated automatically ", avoids the problem of the lifting speed path deficiency that may cause in handling small work procedure section process, and the method that makes can realize speed smooth transition in that work procedure is intersegmental.

4. highly versatile.The inventive method is introduced the notion of " rate conversion length ", at the different acceleration and deceleration method, obtains different speed and regulates parameter automatically, makes the inventive method to match with various acceleration and deceleration algorithm.

Description of drawings

Fig. 1 is the inventive method overview flow chart;

Fig. 2 is a calculated line acceleration and deceleration rate conversion length synoptic diagram of the present invention;

Fig. 3 connects the error synoptic diagram for calculating the intersegmental turning of adjacent programs;

Fig. 4 regulates process flow diagram automatically for the intersegmental connection speed of work procedure in the inventive method;

Fig. 5 connects design sketch for the speed that the existing method of available technology adopting obtains;

The speed connection design sketch that Fig. 6 obtains for adopting the inventive method;

Fig. 7 is for adopting the processing pictorial diagram of the inventive method.

Embodiment

Below in conjunction with accompanying drawing the present invention is described in further detail.

Present embodiment is applied to the inventive method in the digital control system in open type motion control speed connection processing partly of blue sky hardware platform, and the acceleration and deceleration mode is selected linear acceleration and deceleration for use, and its operation result has obtained checking on the three-axis numerical control milling machine.

Hardware platform adopts standard industry level IPC integrated circuit board, and 5X86-133MHz CPU constitutes the 4+1 axis controller as system controller by one ten thousand FPGA devices able to programme, and the FPGA device provides other auxiliary circuits such as digital control system I/O simultaneously.

The important technological parameters of test environment is as follows:

Drive: peace river motor ∑ II Series AC servo;

Digital control system: CPU 5X86-133MHz, RAM-32M, FLASH-32M, I/O-32/24, scrambler input-4, D/A output-4, demonstration-10.4 " Color Liquid Crystal Display;

The speed of mainshaft=24000r/min;

Feed rate F=10000mm/min;

Acceleration time=800ms;

Maximum turning connects error=0.1mm;

Interpolation cycle=2ms;

Present embodiment is with the example that is processed as of representative workpiece program " pentagram " type curve.Should mainly be generated by small straight-line segment by " pentagram " type curve, the average length of small straight-line segment is about 0.8mm.

As shown in Figure 1, the present invention's speed connection method of being used for digital control system has following steps:

The digital control system work procedure is carried out dynamic pre-read processing, and the rate conversion length that obtains between the adjacent workpieces program segment is connected error with the turning; According to the initial connect-speed between the desired machining precision calculating of programming speed of feed, the user adjacent workpieces program segment of turning connection sum of errors work procedure; Automatically regulate connection speed between the adjacent workpieces program segment according to the rate conversion length between the peak acceleration that sets in advance each axis servomotor of digital control system, adjacent workpieces program segment and the initial connect-speed between the adjacent workpieces program segment.

Described dynamic pre-read processing may further comprise the steps:

If total line number of work procedure is n, the approximate all long l that is _Ave, it is p that the reading in advance of work procedure handled line number _n, calculate the dynamic pre-read processing line number of work procedure by following formula:

$p_n\≥\frac{n}{\mathrm{\Δt}}-\frac{l_{\mathrm{ave}}*n}{v*{\mathrm{\Δt}}^2}$ (12)

Wherein v is the programming speed of feed of work procedure, and Δ t is the digital control system interpolation cycle.

Described rate conversion length is under the condition of each axis servomotor peak acceleration of known digital control system, and digital control system is from a movement velocity v ₁Be transformed into another movement velocity v ₂The shortest required length of motion route is asked for corresponding rate conversion length by the peak acceleration of each axis servomotor, starting velocity, termination speed and the realization deceleration planning method that rate conversion adopted of rate conversion.

It is the processing work surface configuration deviation e that the user can allow in digital control system speed connection procedure that described turning connects error, calculates by following formula:

$e\≤\frac{v*\mathrm{\Δt}*\sin \mathrm{\θ}}{\sqrt{8*(1+\cos \mathrm{\θ})}}$ (8)

Wherein v is the programming speed of feed of work procedure, and Δ t is the digital control system interpolation cycle, and θ is the corner angle between the adjacent workpieces program segment.

The inventive method is at the behavioral characteristics of controlled device, introduces the notion of " dynamic pre-read processing ", and according to total line number of work procedure and all long, the pretreated work procedure hop count of dynamic calculation is read processing in advance to work procedure before motion is carried out; Introduce the notion of " rate conversion length " and " turning is connected error ", the connection speed of corner between control adjacent workpieces program segment; The interpolation cycle that the maximum turning that utilizes the corner angle, user of adjacent workpieces program segment in the work procedure to set connects error, programming speed of feed and digital control system obtains the initial connect-speed between the adjacent workpieces program segment; Different acceleration and deceleration mode by initial connect-speed and user adopt can obtain the rate conversion length between the adjacent workpieces program segment; Adopt the intersegmental connection speed Automatic adjustment method of work procedure,, regulate the connection speed between the adjacent workpieces program segment, realize the intersegmental speed smooth transition of work procedure according to the length of work procedure section and the rate conversion length of asking.Concrete speed connection method is as follows:

1) dynamic pre-read processing method:

The connection of digital control system speed can be guaranteed satisfying under the situation of error requirements in the inventive method, and lathe is with the fastest speed operation.Before motion is carried out, must determine the connection speed between the adjacent workpieces program segment, therefore need read in advance to handle to the work procedure section.Especially, in the processing of complex curve and curved surface, come the match complex curve with small straight-line segment or circular arc usually, the work procedure quantity that CAD/CAM generates is many, all long little, if read the work procedure hop count deficiency handled in advance, be easy to cause data famine in the motion process.Otherwise, if it is too much to read the work procedure hop count handled in advance, then prolonged reading the processing time in advance of work procedure, reduced the execution efficient of digital control system.So propose the dynamic pre-read processing method among the present invention,, dynamically arrange pre-treated workpiece program hop count according to the feature of different workpieces program.

The programming speed of feed of known work procedure is v, and the digital control system interpolation cycle is Δ t.If total line number of work procedure is n, the approximate all long l that is _Ave, the work procedure section read to handle line number p in advance _nExpression.For fear of the data famine, needs guarantee the work procedure segment length that the pre-service length of work procedure section has been processed or carried out greater than reality, i.e. any time T that moves at work procedure:

$(p_n+\frac{T}{\mathrm{\Δt}})*l_{\mathrm{ave}}\≥\frac{T}{\mathrm{\Δt}}*v*\mathrm{\Δt}$ (9)

Abbreviation can get:

$p_n\≥T*(\frac{v}{l_{\mathrm{ave}}}-\frac{1}{\mathrm{\Δt}})$ (10)

Because in the work procedure operational process, to carry out the process of acceleration and deceleration at least, again so the total execution time T of work procedure _TopSatisfy:

$T_{\mathrm{top}}>\frac{l_{\mathrm{ave}}*n}{v*\mathrm{\Δt}}$ (11)

Obtain in order to guarantee the data famine in the work procedure operational process, not occur, can be similar to:

$p_n\≥\frac{n}{\mathrm{\Δt}}-\frac{l_{\mathrm{ave}}*n}{v*{\mathrm{\Δt}}^2}$ (12)

By formula (12) as can be seen, the reading in advance of work procedure handled hop count and is directly proportional with total line number of work procedure, is inversely proportional to the average length of work procedure.

2) introduce " rate conversion length ":

Described rate conversion length refers to that under the condition of each axis servomotor peak acceleration of known digital control system digital control system is from a movement velocity v ₁Be transformed into another movement velocity v ₂The shortest required length of motion route is used l in the present invention _cExpression.Rate conversion length is transformed by the termination speed of the starting velocity of the peak acceleration of each axis servomotor, conversion, conversion and realization speed mainly that the acceleration and deceleration mode that adopted determines.At different acceleration and deceleration modes, different rate conversion length solution formulas is arranged.Present embodiment is an example with the linear acceleration and deceleration, and the method for solving of rate conversion length is described.

As shown in Figure 2, wherein the area of dash area by being asked linear acceleration and deceleration rate conversion length.Known linear acceleration and deceleration is at t ₁Speed is v constantly ₁, at t ₂Speed is v constantly ₂, the synthetic peak acceleration of each axis servomotor is a, then the rate conversion length l _cFor from speed v ₁With peak acceleration a (establish linear acceleration and deceleration the boost phase acceleration on the occasion of, be negative value at the decelerating phase acceleration) be transformed into speed v ₂The shortest required motion path.Computing formula is as follows:

$l_c=\frac{1}{2}*({\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">v</figure-callout>}}_1+v_2)*(t_2-t_1)$ (1)

v ₂＝v ₁+a*(t ₂-t ₁)

Can obtain according to formula (1):

$l_c=\frac{1}{2a}*({v_2}^2-{{\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">v</figure-callout>}}_1}^2)$ (2)

Following formula is a method of asking for rate conversion length in the linear deceleration planning.The medium velocity transition length value of being considered as known variables of the present invention.In actual applications, according to the deceleration planning method that is used with the inventive method, ask for corresponding rate conversion length.

3) introduce " turning connection error ":

It is the processing work surface configuration deviation that the user can allow in digital control system speed connection procedure that described turning connects error.At different work procedures and processing request, the maximum turning connection error that the user sets digital control system is the desired minimum machining precision of user.Obtain digital control system with the motion of programming speed of feed in the speed connection processing stage, the turning that produces by place, work procedure turning connects error.If this error connects error smaller or equal to the maximum turning that the user sets, then explanation can not influence the machining precision of system with the programming speed of feed by this turning; Otherwise, then illustrate with the programming speed of feed excessively by the error that this turning produces, needing around the corner, reduction of speed passes through.

The programming speed of feed of known work procedure is v, and the corner angle between the adjacent workpieces program segment is θ, and the digital control system interpolation cycle is Δ t, and it is e that the maximum turning that the user sets connects error _MaxThe length of work procedure section is not the integral multiple of processing step-length usually in the process, so corner certainly leads to the connection error at the adjacent workpieces program segment, if is e with maximal rate by the shape error that the adjacent workpieces program segment produces, as shown in Figure 3, the starting point of work procedure section AB and terminal point are respectively an A and some B among the figure, and the starting point of work procedure section BC and terminal point are respectively a B and put C.Cutter is B by the actual motion path at two work procedure section tie point B places ₀B ₁, then the maximum turning that this moment, system produced connects error for to draw perpendicular to B from the B point ₀B ₁Vertical line BD, its length is e.If straight-line segment B ₀The length of B is l ₁, straight-line segment BB ₁Length be l ₂, straight-line segment B ₀B ₁Length be l ₃, then according to according to sine, Δ B ₀BB ₁Area can be expressed as:

$S_{\mathrm{\&Delta;}{B}_0\mathrm{<figure-callout\; id="1"\; label="B\; B"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">B</figure-callout>}{B}_{}{}_1}=\frac{1}{2}*{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1*l_2*\sin \mathrm{\&theta;}$ (3)

Again because BD perpendicular to B ₀B ₁So,, Δ B ₀BB ₁Area can be expressed as:

$S_{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="0"\; label="B"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">B</figure-callout>}}_0{\mathrm{<figure-callout\; id="1"\; label="BB"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">BB</figure-callout>}}_1}=\frac{1}{2}*l_3*e$ (4)

Can obtain according to the cosine law:

$l_3=\sqrt{{{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1}^2+{l_2}^2-2*{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1*l_2\cos (\mathrm{\&pi;}-\mathrm{\&theta;})}$ (5)

Can obtain connecting error according to formula (3), (4), (5) and be with the turning that maximal rate produces by the adjacent programs section:

$e=\frac{{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1*l_2*\sin \mathrm{\&theta;}}{\sqrt{{{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1}^2+{l_2}^2-2*{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1*l_2\cos (\mathrm{\&pi;}-\mathrm{\&theta;})}}$ (6)

Again because when digital control system was passed through adjacent programs section turning with maximal rate, the turning that is produced connected the error maximum, so can get:

l ₁+l ₂≤v*Δt (7)

And if only if ${\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="S2008100121119E00022.png,S2008100121119E00031.png"\; state="\{\{state\}\}">l</figure-callout>}}_1=l_2=\frac{v*\mathrm{\&Delta;t}}{2}$ The time, error e obtains maximal value, that is:

$e\&le;\frac{v*\mathrm{\&Delta;t}*\sin \mathrm{\&theta;}}{\sqrt{8*(1+\cos \mathrm{\&theta;})}}$ (8)

4) computing method of initial connect-speed:

Described calculating initial connect-speed v _LinkCalculate by following formula:

$v_{\mathrm{link}}=\min \{v,\frac{e_{\max }*\sqrt{8*(1+\cos \mathrm{\&theta;})}}{\mathrm{\&Delta;t}*\sin \mathrm{\&theta;}}\}$ (16)

Wherein v is the programming speed of feed of work procedure, and θ is the corner angle between the adjacent workpieces program segment, and Δ t is the digital control system interpolation cycle, e _MaxThe maximum turning connection error of setting for the user is the desired minimum machining precision of user.

Initial connect-speed depends on that the maximum turning of programming speed of feed, the corner angle between the adjacent workpieces program segment and the customer requirements of work procedure is connected error between the adjacent workpieces program segment.Be specially: the programming speed of feed of work procedure is the maximal value of the intersegmental initial connect-speed of work procedure; Corner angle between the adjacent workpieces program segment is more little, and the intersegmental initial connect-speed of work procedure is big more; It is big more that the maximum turning that the user allowed connects error, and the initial connect-speed between the adjacent workpieces program segment is big more.

According to formula (8), can obtain the intersegmental turning of work procedure and connect error and be:

$\max \left\{e\right\}=\frac{v*\mathrm{\&Delta;t}*\sin \mathrm{\&theta;}}{\sqrt{8*(1+\cos \mathrm{\&theta;})}}$ (13)

Obviously, connection error in turning is connected with the desired maximum turning of user following relation between the error:

e≤e _max (14)

Can get turning connection speed v between the adjacent workpieces program segment by formula (19), (20) _LinkSatisfy following relation:

$v_{\mathrm{link}}\&le;\frac{e_{\max }*\sqrt{8*(1+\cos \mathrm{\&theta;})}}{\mathrm{\&Delta;t}*\sin \mathrm{\&theta;}}$ (15)

Again because the turning connection speed between program segment less than the program speed of work procedure, so:

$v_{\mathrm{link}}=\min \{v,\frac{e_{\max }*\sqrt{8*(1+\cos \mathrm{\&theta;})}}{\mathrm{\&Delta;t}*\sin \mathrm{\&theta;}}\}$ (16)

5) regulate connection speed between the adjacent workpieces program segment automatically:

As shown in Figure 4, the connection speed of regulating between the adjacent workpieces program segment automatically in the inventive method may further comprise the steps:

If the first motion speed V of work procedure unit one program segment _InitBe zero, establish the termination movement velocity V of last work procedure section in the dynamic preprocessing process _EndBe zero;

If motion is from the first motion speed V of work procedure section _InitBe transformed into and stop movement velocity V _EndBetween required rate conversion length l _cIf the length l of＞work procedure section is and first motion speed V _Init＜termination movement velocity V _End, utilize known work procedure section operation initial velocity V _InitWith work procedure segment length l, with reference to asking for the rate conversion length l _cMethod, obtain under the situation of given length l, the motion from first motion speed V _InitThe highest termination speed V that can reach _End', and make V _End=V _End', connection speed is regulated termination automatically;

If motion is from the first motion speed V of work procedure section _InitBe transformed into and stop movement velocity V _EndBetween required rate conversion length l _cIf the length l of＞work procedure section is and first motion speed V _Init＞termination movement velocity V _End, by asking for the rate conversion length l _cMethod, obtain at given length l and stop movement velocity V _EndSituation under, the motion the highest first motion speed V that can reach _Init', and make V _Init=V _Init', the termination movement velocity of changing adjacent previous work procedure section is V _Init', and under new termination movement velocity condition, regulate the first motion speed of adjacent previous work procedure section by the automatic regulating step of motion connection speed;

If motion is from the first motion speed V of work procedure section _InitBe transformed into and stop movement velocity V _EndBetween required rate conversion length l _cThe length l of＞work procedure section, according to the definition of rate conversion length as can be known, this moment first motion speed V _InitWith termination movement velocity V _EndInevitable unequal;

Above-mentioned steps is carried out repeatedly, regulates end condition automatically up to satisfying connection speed.

The described execution repeatedly is meant in the speed adjustment process of current work procedure section, automatically regulate end condition if can't satisfy connection speed, then trace back to its adjacent previous or preceding several work procedure sections, till satisfying connection speed and regulating end condition automatically.

If motion is from first motion speed V _InitBe transformed into and stop movement velocity V _EndBetween required rate conversion length l _cThe length l of≤work procedure section regulates stopping automatically.

(horizontal ordinate is unit with the interpolation cycle to the speed planning curve that the existing method of employing obtains as shown in Figure 5, ordinate is represented pairing process velocity, unit is mm/min), and adopt the inventive method speed planning curve as shown in Figure 6, actual processing exemplar is as shown in Figure 7.Can obtain as drawing a conclusion from the contrast of rate curve:

1. our bright speed connection method acceleration and deceleration number of times is few, and rate curve is level and smooth.During processing " pentagram " type curve, the present invention only handles through tens acceleration and deceleration, and classic method needs more than 200 acceleration and deceleration to handle;

2. our bright speed connection method has realized that the intersegmental speed of work procedure connects, and classic method does not realize that the intersegmental speed of work procedure is connected, and speed is zero after every section process finishing;

3. our bright speed connection method process velocity height.Because for identical initialization controlled variable, process velocity on average is approximately about 7000mm/min during the inventive method processing " pentagram " type curve, with the time of about 4000 interpolation cycles, and the classic method process velocity on average is approximately 2600mm/min, has used the time of about more than 10000 interpolation cycles;

4. our bright speed connection method processing shows the smoothness height.In the bright method process of we, speed continuity height, speed is few zero point, has reduced because system start-up, stop the machine vibration to be caused; And the employing classic method, stops frequent caused vibration effect work procedure finished surface smoothness at system start-up.

Claims (5)

1. speed connection method that is used for digital control system is characterized in that having following steps:

The digital control system work procedure is carried out dynamic pre-read processing, and the rate conversion length that obtains between the adjacent workpieces program segment is connected error with the turning;

According to the initial connect-speed between the desired machining precision calculating of programming speed of feed, the user adjacent workpieces program segment of turning connection sum of errors work procedure;

Automatically regulate connection speed between the adjacent workpieces program segment according to the rate conversion length between the peak acceleration that sets in advance each axis servomotor of digital control system, adjacent workpieces program segment and the initial connect-speed between the adjacent workpieces program segment;

Wherein said rate conversion length is under the condition of each axis servomotor peak acceleration of known digital control system, and digital control system is from a movement velocity v ₁Be transformed into another movement velocity v ₂The shortest required length of motion route by the peak acceleration of each axis servomotor, starting velocity, termination speed and the realization deceleration planning method that rate conversion adopted of rate conversion, is asked for corresponding rate conversion length;

It is the processing work surface configuration deviation e that the user can allow in digital control system speed connection procedure that described turning connects error;

Described dynamic pre-read processing may further comprise the steps:

If total line number of work procedure is n, the approximate all long l that is _Ave, it is p that the reading in advance of work procedure handled line number _n, read to handle line number in advance by what following formula calculated work procedure:

$p_n\&GreaterEqual;\frac{n}{\mathrm{\&Delta;t}}-\frac{l_{\mathrm{ave}}*n}{v*\mathrm{\&Delta;}{t}^2}---\left(12\right)$

Wherein v is the programming speed of feed of work procedure, and Δ t is the digital control system interpolation cycle;

Described processing work surface configuration deviation e calculates by following formula:

$e\&le;\frac{v*\mathrm{\&Delta;t}*\sin \mathrm{\&theta;}}{\sqrt{8*(1+\cos \mathrm{\&theta;})}}---\left(8\right)$

Wherein v is the programming speed of feed of work procedure, and Δ t is the digital control system interpolation cycle, and θ is the intersegmental corner angle of adjacent programs;

Initial connect-speed v between described calculating adjacent workpieces program segment _LinkCalculate by following formula:

$v_{\mathrm{link}}=\min \{v,\frac{e_{\max }*\sqrt{8*(1+\cos \mathrm{\&theta;})}}{\mathrm{\&Delta;t}*\sin \mathrm{\&theta;}}\}---\left(16\right)$

Wherein v is the programming speed of feed of work procedure, and θ is the corner angle between the adjacent workpieces program segment, and Δ t is the digital control system interpolation cycle, e _MaxThe maximum turning connection error of setting for the user is the desired minimum machining precision of user.

2. by the described speed connection method that is used for digital control system of claim 1, it is characterized in that: the connection speed between described automatic adjusting adjacent workpieces program segment may further comprise the steps:

If the first motion speed V of first program segment of work procedure _InitBe zero, establish the termination movement velocity V of last program segment in the dynamic pre-read processing process _EndBe zero;

If motion is from first motion speed V _InitBe transformed into and stop movement velocity V _EndBetween required rate conversion length l _cIf the length l of＞work procedure section is and first motion speed V _Init＜termination movement velocity V _End, utilize the first motion speed V of known work procedure section _InitWith work procedure segment length l, with reference to asking for the method for rate conversion length, to obtain under the situation of the length l of given work procedure section, motion is from first motion speed V _InitThe highest termination speed V that can reach _End', and make V _End=V _End', connection speed is regulated termination automatically.

3. by the described speed connection method that is used for digital control system of claim 2, it is characterized in that: if first motion speed V _Init＞termination movement velocity V _End,, obtain length l and termination movement velocity V in given work procedure section by asking for the method for rate conversion length _EndSituation under, the motion the highest first motion speed V that can reach _Init', and make V _Init=V _Init', change the termination movement velocity V of adjacent previous work procedure section _End=V _Init', and under new termination movement velocity condition, regulate the first motion speed of adjacent previous work procedure section by the automatic regulating step of motion connection speed;

Above-mentioned steps is carried out repeatedly, regulates end condition automatically up to satisfying connection speed.

4. by the described speed connection method that is used for digital control system of claim 3, it is characterized in that: the described execution repeatedly is meant in the speed adjustment process of current work procedure section, automatically regulate end condition if can't satisfy connection speed, then trace back to its adjacent previous or preceding several work procedure sections, till satisfying connection speed and regulating end condition automatically.

5. by the described speed connection method that is used for digital control system of claim 2, it is characterized in that: if motion is from first motion speed V _InitBe transformed into and stop movement velocity V _EndBetween required rate conversion length l _cThe length l of≤work procedure section, connection speed are regulated termination automatically.

Images