CN102298343A - Approximate uniform acceleration control technology of servo motor of automatic hosiery machine - Google Patents

Abstract

The invention relates to an approximate uniform acceleration control technology of a servo motor of an automatic hosiery machine, which relates to the technical field of equipment of a computerized electronic jacquard hosiery machine and aims at providing technical support for implementing efficient, steady and reliable operation of a system and implementing various jacquard functions for a novel embedded jacquard hosiery machine. The approximate uniform acceleration control technology comprises a dual-microcontroller core scheme designed for the embedded hosiery machine, specialization and cooperation of two cores, equipment at periphery of the cores, communication modes between the two cores, and the like; and then, an acceleration control technology of the servo motor is checked and described emphatically, the approximate uniform acceleration control technology is characterized in that the technology is a segmented approximate uniform acceleration control technology, program for the technology is easy to implement and less in calculation, so that load on an MCU (Micro Control Unit) is greatly reduced, and the technology is suitable for embedded equipment with limited resource; and simultaneously, the technology is characterized in that the technology is portable for operation and has strong applicability, and calculation at different levels can be set according to difference of system hardware levels; the phenomenon of failure of algorithm is avoided in the technology, the servo motor can run safely and reliably, practical experiments find that speed of the servo motor changes uniformly, speed control effect is better, and the bigger the value of D is, the better the speed reduction effect is.

Description

Automatically the servomotor of hosiery machine is similar to the uniform acceleration control technology

Technical field

The invention belongs to computer jacquard footwear machine technical field, particularly relate to a kind of approximate uniform acceleration control technology of servomotor of automatic hosiery machine.

Background technology

At present knitting and the present forward of relevant device is efficient, energy-saving and environmental protection and Electronic Control direction develop, stable performance, the update paces are accelerated.The jacquard weave function of equipment enlarges, and automatic control level improves.The height control of electronic system accurately provides guarantee to improving the quality of products.So adopt electronic technology, transform traditional industries, improve the electromechanical integration level, promoted the technical progress of knitting industry.Present knitting equipment is strengthened application of electronic technology just energetically.

And computer stocking technology of current China and developed country also have sizable gap.Particularly with Italy, Korea S, Japanese three state's gaps are especially big.Their hosiery machine at aspects such as high-tech application, design philosophy, manufacturing accuracy and product appearance images all leading far away we, therefore, deep day by day along with the foreign economic technical co-ordination, high-grade hosiery machine market is almost completely captured by their technology.Under the current national conditions of China, aim at external advanced hosiery machine technique direction, exploitation has the hosiery machine technology of independent intellectual property right, and progressively catches up with external advanced level, seems very urgent important.

In current hosiery machine device systems, servomotor is in the position of core all the time, the solenoid valve of periphery, the needle selection device all is main shaft with the servomotor, the operation stability of servomotor, reliability, and the speed of operation has directly determined the efficient of this hosiery machine, performance.And in the control system of hosiery machine, the speed control of servomotor, location detecting technology is again the technology of the core the most of whole hosiery machine system, so the decision of the quality of a hosiery machine servomotor control technology is the quality of this equipment.With regard to the speed control of servomotor the influence of hosiery machine efficient is done down for example below:

When socks wove at heel, servomotor must turn round about 70 times by positive and negative both direction repeatedly.And the running speed of the servomotor of this hosiery machine is very fast, reach 900r/min, under so high speed, be impossible turn round in the other direction immediately, a process of slowing down must be arranged, slow down and finish also must have a process of quickening, seem very important of the process of these acceleration and deceleration concerning the hosiery machine system, at first excessive acceleration and deceleration process servomotor can't bear, and the solenoid valve of the periphery of the syringe of as easy as rolling off a log damage driven by servomotor and the knitting needle on the syringe thereof, must consider the efficiency of acceleration and deceleration simultaneously, low excessively acceleration-deceleration is lost time, and has directly reduced the production efficiency of socks.

For example, in servo drive signal PWM periodic quantity is acceleration and deceleration scheme under the constant increment, prolong individual 0.25 second if the process of acceleration and deceleration, motor process that needs 4 times acceleration and deceleration repeatedly altogether then, then need many prolongations 1 second, socks need about 70 times repeatedly altogether, time waste that will about 70 seconds, and the present required time of socks braiding is about 3 minutes as long as (the heel of a sock braiding accounts for very most of the time), as seen a time-delay of 0.25 second has directly reduced economic benefit of enterprises with regard to reducing the production efficiency of socks greatly.

Therefore the acceleration-deceleration controlling schemes of the servomotor of hosiery machine seems very important, and is efficient, and acceleration and deceleration control method directly has influence on the efficient of hosiery machine operation reliably, and serviceable life, thereby is directly connected to socks production cost, benefit.

The main control assembly of computer stocking concentrates on the knit operation platform, in technological requirement and the physical construction of analyzing the hosiery machine system, and electrical specification is found: the reference mark that the computer stocking system need control is more, comprise 64 tunnel solenoid valve, 96 needle selection cuttves of 6 needle selection devices, the stepper motor of two-way, No. one servomotor, the two-way electromagnetic sensor, and the external fault of ten multichannels interrupts detecting.The distribution of the reference mark solenoid valve needle selection device of hosiery machine components of system as directed as shown in Figure 1, the solenoid valve of system is far above this part, have 60 multichannels, also have 6 groups needle selection device to control in addition, its distribution plan as shown in Figure 2,1C～5C and 1F are 6 groups of needle selection devices among the figure, every group of needle selection cutter that has 16, and each all is an independently reference mark, and each shuttle in the jacquard weave comb among Fig. 2 is that solenoid control is arranged, and each also is reference mark independently.At first to monitor, the reference mark of detecting is so many, secondly as servomotor, the electric requirement of needle selection device is again than higher, the needle selection device requires rapid reaction, only carry out s operation control with regard to above electrical control point with regard to needing a large amount of cpu resources in this case, adopt a slice DSP to control and seem tight short.

And this hosiery machine system also requires to be equipped with one 3.5 cun lattice lcd, 40 buttons nearly, operation keyboard, and the LED warning lamp of multichannel, E ²ROM storer, clock chip and remote communication module etc. need a lot of system resource with regard to man-machine interface this part, are unrealistic if only adopt core to carry out so many task operating, and in the braiding process that runs up of this hosiery machine, be that requirement can be carried out liquid crystal, button, reach and host computer etc. communicates, if not having an independent core operates, cannot say for sure to demonstrate,prove socks, triangular knife, solenoid valve, safety such as servomotor, stable work.

Summary of the invention

The object of the present invention is to provide a kind of approximate uniform acceleration control technology of servomotor of automatic hosiery machine.

The objective of the invention is to adopt such technical solution to realize: to it is characterized in that to be provided with two variablees: int n; Float b; Wherein b is used to preserve the increment b (d) of this section, n is used for counting, each PWM end cycle, and the value of register changes to N (d)+n*b (d) and rounds, n is from adding 1 simultaneously, if n arrives n (d), then enter the deceleration of next section, b composes next section b (d) again, n restarts meter from 0, after reaching the n (d) of this section, enter next section, until decelerating to the set goal value.

The present invention passes through at each PWM end cycle, the value of register changes to N (d)+n*b (d) and rounds, and n is from adding 1, if n arrives n (d) simultaneously, then enter the deceleration of next section, b composes next section b (d) again, n from 0 restart the meter, reach the n (d) of this section after, enter next section Acceleration Control, can start servomotor, the uniform acceleration of stopped process is carried out efficient, portable control, and is applicable to a kind of control technology of the embedded hosiery machine that computing power is limited.

Description of drawings

Fig. 1 syringe periphery solenoid valve distribution plan

The distribution plan of Fig. 2 needle selection device and jacquard weave comb

Fig. 3 syringe cylinder structure synoptic diagram

Fig. 4 control principle block scheme of the present invention

Embodiment

The analysis of embedded hosiery machine control section: when two microcontrollers of employing DSP and ARM were controlled, the division of labor of DSP and ARM was as follows:

DSP mainly is responsible for the field control control section of hosiery machine, be responsible for the control timing signal output of on-the-spot controlling object such as solenoid valve, needle selection device, magnetic induction switch, stepper motor and servomotor and the feedback signal of gathering respective handling, realize time real control each electronic-controlled installation.Because of considering the high-capacity FLASH memory module of preserving the flower graphic data, be and the needle selection device, the operation of full-jacquard mechanisms such as yarn feeding comb is directly related, it is mutual to carry out lot of data, therefore this module also is responsible for by DSP, resultant, spend the mutual USB interface of graphic data also to be integrated on the DSP control panel with host computer.

And ARM core chief leading cadre machine interactive interface etc., mainly be in charge of lattice type LCD display screen, LED warning lamp, keyboard, E2ROM storer, clock chip and, and can outwards blaze abroad important informations such as woven condition by the telecommunication mode.

Communicating by letter between these two cores of DSP and ARM, consider that amount of communication data is little, but the reliable request to data transmission is higher, so adopt the mode of CAN bus, CAN module that at first these two cores are all integrated directly adopts the CAN bus to believe, reduces the cost of control system, also simplified the complexity of system, made system more stable.

Secondly CAN has following characteristic: low cost; High total line use ratio; Far data transmission distance (reaching 10km); High-speed data transmission speed (up to 1Mbps); Can receive or shield this message according to the ID decision of message; Reliable fault processing and error-detection mechanism; After being destroyed, the information that sends to retransmit automatically; Node has the function that withdraws from bus automatically under wrong serious situation.

Introduce servomotor below, it links to each other with the syringe of hosiery machine, play the control syringe and do the running of positive and negative both direction, it is the core component of hosiery machine, its structural representation as shown in Figure 3,6 groups of needle selection devices of syringe circumferential distribution, and a large amount of solenoid valves all is to realize various braid movements under the cooperation of servomotor syringe as shown in Figure 1, shown in servomotor speed, the quality of performance has just directly determined the quality of hosiery machine system, do further statement with regard to the control technology of servomotor below: at first inquire into the feasibility verified two kinds of control methods, proposed to be applicable to the acceleration and deceleration control technology of the servomotor of embedded hosiery machine control system then.

Acceleration and deceleration technology under the one .PWM periodic quantity constant increment

The pwm signal of servomotor is to be produced by the PWM module that is integrated in the single-chip microcomputer, under the pattern of selecting, as long as give certain value to the period register of PWM module, and the dutycycle of pwm signal is arranged to 50%, mode is arranged to, cycle length, then the PWM module will produce the pwm signal of fixed frequency to the automatic assignment pattern.Be to realize the acceleration and deceleration control of servomotor, must each pwm signal cycle then, give the period register value again.

If the value of current period register is N, next value is N+b, and the instruction cycletime of system is: Δ t, and the pwm pulse number of this servomotor one circle is 2500, then the acceleration a of servomotor is:

$a=\frac{\frac{1}{N*\mathrm{\Δt}*2500}-\frac{1}{(N+b)*\mathrm{\Δt}*2500}}{(N+N+b)*\mathrm{\Δt}}(r/s^2)---\left(1\right)$

If arrive each cycle length, next periodic quantity is done an identical value and is added up, promptly b is a constant in the formula, then through simplifying:

$a=\frac{b}{{\mathrm{\Δ}}^{2}t*2500}*\frac{1}{N(N+b)(2N+b)}(r/s^2)---\left(2\right)$

The left-half on equation the right is a constant, and the right half part denominator after launching is:

$\frac{1}{{2N}^3+{3\mathrm{bN}}^2+b^{2}N}$

B is the increment in next cycle in the formula, generally is an amount much smaller than N, and as seen, a follows from formula

Be directly proportional, along with the increase of N, the speed that a is into 3 powers reduces.As seen, initial a is bigger from the practice experiment, and along with the time advances, a reduces rapidly, and the speed of corresponding motor is to reduce rapidly the super beginning, and the variation of speed is more and more slower afterwards.

In order to allow the servomotor of hosiery machine be reduced to 100 commentaries on classics apace from running up of 900 commentaries on classics, stop then, suppose to require to finish in 3 seconds, if undertaken by this scheme:

The instruction cycle Δ t of native system is: 1/ (22.1184*10 ⁶) (calculating by clock period of the MCU of this control system), when rotating speed was 900, PWM through the value of period register is: 591,100 transferred to: 5301 as calculated; Can get calculating formula:

$591n+\frac{b(1+n)n}{2}=\frac{T}{\mathrm{\Δt}}---\left(3\right)$

bn＝5301-591

N is that speed is from the 900 pwm pulse numbers that drop to during 100 in the formula; T is reduction of speed T.T., and T=3 substitution second is tried to achieve:

n≈22523

b≈0.209

Now calculate motor and reduced to for 300 times that spend from speed 900, during 300 commentaries on classics, the value of PWM period register is: 1767; By bn ₃₀₀=1767-591 solves:

n ₃₀₀＝5627

The value that is the PWM period register adds up with b at every turn, and distributing the speed that just can reach after 5627 pulses 300 changes, n ₃₀₀, the b=0.209 substitution

:

T ₃₀₀≈0.3；

From result of calculation as can be seen, change to decelerate to 300 and change and only spent 0.3 second from 900 by this scheme servomotor, forwarding 100 to from 300 changes and has but spent 2.7 seconds, can see that 900 to 300 acceleration that change are to be far longer than 300 to forward 100 to and change, acceleration present be by Ratio descend.

Though it is simple from the speed-buffering scheme of finding out this motor, program realizes convenient, but his decelerability is very poor, motor dropped to 300 from 900 commentaries on classics in 0.3 second change, here acceleration is obviously excessive, will cause the damage of servomotor for a long time, and can cause the solenoid valve of hosiery machine syringe and periphery thereof, the needle selection device, the loss of knitting needle.Spent 2.7 seconds and forward 100 commentaries on classics to from 300, the acceleration here is obviously too small again, loses time, and has directly reduced the production efficiency of hosiery machine.

Two. the discussion of theoretical even acceleration and deceleration control

Proposed to require the controlling schemes of the even acceleration and deceleration of motor under the demonstration of such scheme, known by formula 1 to make acceleration at the uniform velocity, promptly a remains unchanged, and then b must change along with the variation of N, extracts after b simplifies to be:

ANb ²+(3AN ²-1)b+2AN ³＝0 (4)

A=625a Δ wherein ²t

Solve:

$b=\frac{-({3\mathrm{AN}}^2-1)\±\sqrt{{({3\mathrm{AN}}^2-1)}^2-{8A}^2{N}^4}}{2\mathrm{AN}}---\left(5\right)$

From then on formula can be reached a conclusion: acceleration a as requested in theory, and the value N of current PWM period register, just can be in the hope of the increment b of next cycle, like this, every mistake PWM cycle just calculates the increment of next cycle, register value is done accordingly added up then, so, loop iteration goes down, and the speed of motor will present the value of adjusting to expection at the uniform velocity, but finds in the application in practice of single-chip microcomputer:

With Δ t=1/ (22.1184*10 ⁶), the N value 591 of rotating speed when 900 change, acceleration is the same, reduces to 100 from 900 in 3 seconds, then a=40/9 (r/s ²) substitution formula 2, get denominator:

2AN=2500* (40/9) * (1/22.1184) ²* 10 ^-12≈ 2.27*10 ^-11Be a minimum value, as calculated, (the 3AN in formula 2 molecules ²-1) ²-8A ²N ⁴Also be a minimal value, empirical tests finds that this scheme has following deficiency:

1) ask the calculating of b extremely complicated, calculated amount is very big, is applied on the Single Chip Microcomputer (SCM) system, if each PWM cycle all will calculate one time, then calculated amount is excessive, will take a large amount of cpu resources, and the reference mark of hosiery machine system, operand itself is just very big, and the rotating speed of syringe is very high, to the time of throwing into the control accurately of needle selection device, real-time is very high, cpu resource is very limited, if add a little algorithm application, then CPU will hold and can't stand computation load like this.

2) empirical tests, the b that solves may be the less decimal less than 1, especially when just having reduced speed now at a high speed, and period register must be shaping, then the value of next period register will remain unchanged, several PWM waveforms that promptly might link to each other can remain unchanged, at this moment, the N value in next cycle remains unchanged, then behind this end cycle, the b that calculates will remain unchanged again, then phase week after next will remain unchanged again, so go down, and the value of period register will be constant forever, iteration will be made mistakes, and algorithm lost efficacy.

Through being discussed, checking finds, the value in each driven by servomotor PWM cycle of as above meticulous calculating, and possible in theory, but realize relatively difficulty in the application in practice, therefore a kind of method of piecewise approximation uniform acceleration control has been proposed.The method feature is as follows:

Suppose to require speed to change grand from 900 in 3 seconds and to 100 commentaries on classics this moderating process is divided into 10 sections (11 speed points), the time also is divided into 10 parts equably, and is as shown in table 1:

Table 1 speed 10 equal portions tables

	0	1	2	3	4	5	6	7	8	9	10
												Speed	900	820	740	660	580	500	420	340	260	180	100
Time	0	0.3	0.6	0.9	1.2	1.5	1.8	2.1	2.4	2.7	3

The process of slowing down is divided into 10 sections, and every section speed that reduces is all identical, and the time of every section deceleration is also identical, with every section moderating process as one on the whole, every section acceleration all is:

$\frac{80}{60*(3/10)}$ I.e. 40/9 (r/s ²)

And, reducing the resource occupation of CPU in order to simplify calculating, each cycle of period register in every period is done identical adding up.Though still acceleration of the speed in every section like this just to begin to prove

Change, but the velocity shooting that slow down this moment is less, the time period yet less (if the Duan Yue that divides is many, then more little), in this velocity shooting, the variation of acceleration a also can be very not big, and on the whole, speed is with uniform acceleration 40/9 (r/s basically ²) change.

The hop count of hypothesis branch is D now, and the time of deceleration is T, N (d) (d=1,2,3...D) be the value of each speed point period register, native system speed is after reducing to 100,100 rotating speeds from 900, can close servomotor safely, the braking of motor energy safety, calculate N (d):

$\frac{1}{\mathrm{\Δt}*N\left(d\right)*2500}=(\frac{(900-100)*(D-d)}{D}+80)/60---\left(6\right)$

D from 0 to D; Divided by 60 being in order to be transformed into r/second from r/min:

$N\left(d\right)=\frac{D}{(10D-9d)*\mathrm{\Δt}*1250}---\left(7\right)$

With d=1,2,3....D substitution respectively obtains posting from 900 cycles that forward D speed point of 100 commentaries on classics to

The storage value, can be in internal memory allocated size be that the one-dimension array of D+1 is used for preserving, as follows:

int?N[D]＝{N(0)，N(1)....N(D-1)，N(D)}；

Calculate the increment b in each section below, n for the PWN umber of pulse that will send in each section by

$N\left(d\right)n+\frac{b\left(d\right)(1+n\left(d\right))n\left(d\right)}{2}=\frac{T}{D*\mathrm{\Δt}}---\left(8\right)$

b(d)n(d)＝N(d+1)-N(d) (9)

Simplify:

$n\left(d\right)=\frac{2\frac{T}{D*\mathrm{\Δt}}+N\left(d\right)-N(d+1)}{N(d+1)+N\left(d\right)}---\left(10\right)$

$b\left(d\right)=\frac{N(d+1)-N\left(d\right)}{n\left(d\right)}---\left(11\right)$

The corresponding d of substitution can obtain the n (d) of each section correspondence, and b (d).

Two variablees are set: int n; Float b; B is used to preserve the increment b (d) of this section, n is used for counting, each PWM end cycle, and the value of register changes to N (d)+n*b (d) and rounds, n is from adding 1 simultaneously, if n arrives n (d), then enter the deceleration of next section, b composes next section b (d) again, n restarts meter from 0, after reaching the n (d) of this section, enter next section, until decelerating to the set goal value.

Beginning in program, can import T deceleration time of expection easily, and the segments D that wants, can obtain the interior umber of pulse n (d) of segmentation speed point N (d) and each segmentation easily as top formula, by formula 3, formula 4 is known, n (d) can try to achieve as long as N (d+1) and N (d) are done simple plus and minus calculation, b (d) also is so, compares theoretical uniform acceleration control method, and calculated amount is to have reduced from far away.

Applicability of the present invention is strong, can be according to the high and low layered difference of system hardware level, change easily, the calculated amount of different levels is set, verify as follows: big more if D obtains, then segmentation is many more, and the control of acceleration and deceleration is then accurate more, the control effect is good more, but the Duan Yue of branch is many, and the calculated amount of requirement is just many more, load to MCU is also heavier, therefore in different application scenarios, the value of D can be set easily, in the precision that reaches acceleration and deceleration control, be unlikely to MCU is caused too much burden, can be according to the requirement of system and the level of software and hardware, the value of averaging out between degree of accuracy and CPU calculated amount.

Along with the value of D is increasing, b (d) value can become more and more littler, the phenomenon less than 1 decimal also can occur, the register value in the next cycle in the program is rounding for N (d)+n*b (d), possible n gets 1,2, and n*b (d) is still less than 1 decimal, illustrate that having two or three identical pulses of cycle exists, but along with the change gradually of n is big, n*b (d) always can be greater than 1, and so the value of period register also can change, invariability can not appear, thereby failure phenomenon.

Claims (2)

1. the servomotor of hosiery machine is similar to the uniform acceleration control technology automatically, it is characterized in that being provided with two variablees: int n; Float b; Wherein b is used to preserve the increment b (d) of this section, n is used for counting, each PWM end cycle, and the value of register changes to N (d)+n*b (d) and rounds, n is from adding 1 simultaneously, if n arrives n (d), then enter the deceleration of next section, b composes next section b (d) again, n restarts meter from 0, after reaching the n (d) of this section, enter next section, until decelerating to the set goal value.

2. the approximate uniform acceleration control technology of the servomotor of automatic hosiery machine according to claim 1 is characterized in that

D=1,2,3....D substitution respectively obtains from 900 forwarding the 100 period register values of changeing D speed point to, can be in internal memory allocated size be that the one-dimension array of D+1 is used for preservation, as follows: intN[D]={ N (0), N (1) ... ..N (D-1), N (D) }; Increment b in each section, n for the PWN umber of pulse that will send in each section is

Simplification can get:

The corresponding d of substitution can obtain the n (d) of each section correspondence, and b (d).

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