DD246854A1 - CIRCUIT ARRANGEMENT FOR CONTROLLING MULTIPLE INDEPENDENT MOTION SYSTEMS - Google Patents

Abstract

Application: Numerical program controls. The aim of the invention is to increase the quality of the workpieces to be produced while reducing the processing times and minimizing the required technical effort. The object of the invention is to provide a circuit arrangement for controlling a plurality of independent motion systems, wherein the undisturbed continuous-path operation of the movement systems over the known mass is made possible. The essence of the invention is that the Werkstueckprogrammspeicher are connected via a selector with the function generator for sentence processing. The execution times of the processed records are calculated in the downstream calculation unit. To this a distributor is connected, which are followed by the buffer memory of the motion systems. The sum of the execution times of the records of each buffer memory is fed to a comparator, which is followed by an evaluator charged with specifiable criteria. The evaluator continues to receive track control operation signals and is connected to control inputs of the selector and the dispatcher. Fig. 1

Description

-2- 248 854

WP G 05 B / 284581 4 illustrated solution refers to the control of a movement sequence. On the other hand, if a numerical control realizes several independent movements, the motion systems are controlled by different programs. Due to the different processing of the workpieces arise at different times and for different motion systems problems in web control operation, resulting from the unidentifiable number of successive sets with low paths and high web speeds.

Object of the invention

The aim of the invention is to increase the quality of the workpieces to be produced, at the same time reducing the processing times and minimizing the technical complexity required.

Explanation of the essence of the invention

By the invention, the technical problem is solved to provide a circuit arrangement for controlling a plurality of independent movement systems, the undisturbed continuous-path operation of the movement systems is made possible beyond the known extent.

Each motion system has a part program memory and a buffer memory for a set number of sentences, summers for the execution times of the buffered sets, and AND gates for the path control operation information of the sets. Furthermore, the circuit arrangement includes a function generator for the sentence processing. The essence of the invention is that the workpiece program memory are connected via a selector to the function generator, which is followed by an arithmetic unit, which is connected to a distributor for calculating the execution times of the processed sentences. The distributor is followed by the buffer storage of the movement systems. To a comparator are summed the execution times of the buffered sets of each motion system. The comparator result output of the comparator and the outputs of the AND gates for the path control operating signals are connected to an evaluator having presettable evaluation criteria connected to a control input of the selector and to a control input of the distributor.

Depending on the structure of the specific control system, the evaluator is given corresponding evaluation criteria in order to initiate the sentence processing for a specific motion system. Decisive for the criteria are the number of movement systems and their ranking among each other.

Since the numerical control can prepare a sentence only for one of the simultaneous independent movements, a weighting has to be made which of the motion sequences is to be given priority. In the case of time-division processing, the critical movement sequence must receive correspondingly more time shares. The weighting of the individual movements is carried out on the basis of the execution times of the pending sentences, which are determined by means of an arithmetic unit.

For processing in the function generator, priority is given to the sets of that movement system whose sum of the execution times of the sets in the buffer with continuous-path operation is the smallest compared to the other movement systems. It is a prerequisite that all these sets are traversed in the Bahnsteuerbetrieb. This can be seen from the signal of the associated AND gate, which is supplied to the evaluator.

If a block located in the buffer ends or interrupts the continuous-path mode, the respective motion system is no longer included in this priority selection.

If the buffers of the motion systems located in the path control mode are filled, movement systems not in the path control mode can be operated with the preparation of sentences.

If there is no or interrupted continuous-path operation in all movement systems, then the selection of the movement system can be made according to a fixed sequence, according to the number of sets in the buffer or also after the sum of the execution times.

embodiment

The invention will be explained in more detail below using an exemplary embodiment. The drawings show:

1 shows the circuit arrangement according to the invention for controlling three independent motion systems, FIG. 2 shows the buffer structure for three independent motion systems,

Fig. 3: the example of an evaluator for three equal-ranking independent motion systems, Figure 4: the representation of a circular motion in the plane.

Referring to FIG. 1, the workpiece program memories S1, S2, S3 are connected to the selector SL, to which a series circuit of function generator FG, arithmetic unit RW and distributor VT is connected downstream. The distributor VT is connected to the buffer memory of the first P1, the second P 2 and the third P3 movement system. As can be seen from Figure 2, each buffer P1, P2, P3 contains η sets, each set comprising its execution time t _ik (i = 1,2,3; K = i ... n). Referring to Fig. 1, the buffer memory areas P _ik having the execution times t _{ik are} connected to the corresponding summers A1, A2, A3 and the areas for the path control operation information of each set are connected to the corresponding AND gates UI, U 2, U3. The adders A1, A2, A3 are fed via the comparator VG to the evaluator BW, which is also connected to the outputs of the AND gates U1, U 2, U 3 and the output side to the distributor TV and the selector SL.

The memories S1, S2, S3 contain the sets of the workpiece program for the respective movement system. The selector SL produces the connection of an appropriate memory S1, S2 or S3 to a function generator FG for the sentence processing, depending on a specific control code. The function generator FG delivers the sentence in such a way that it is needed for the execution. The information of the on-line control enterprise for the sentence concerned is contained therein. To calculate the execution times t _{ik of} the sets, the arithmetic unit RW is connected to the function generator FG. The arithmetic unit RW wins the execution times t _{ik of} the sets from the valid feed (web speed) and the programmed path in the corresponding block

 For a three-dimensional linear motion, the execution time t ^ follows

_ " 7a χ ² +

V - Feedrate x, y, ζ - Coordinate differences

 In a circular movement in the plane, shown in Figure 4 shows:

^t ik ⁼ T ^{with s} ^ ^a + "^

where h - = R -7 R ² - (-) ² 'and a ² = ix ² + Ay

ormita = 2R · sin-

and S = -4r- · R · α · α [degrees]

- 4π _. a

S = -R-arcsine

360 2 R

S = 0.0349 - R arc sin The result of a helix movement in space is:

S _H = Vs ₁ /.fS ² 'and t _lk - /

Sh - Helix Way. ,

Sl - path of the linear axis

S-way of the circular arc

The sentence completed with the execution time t _jk passes via the distributor VT into the buffer memory P1, P 2 or P3 assigned to the movement system. In each buffer memory P1, P2 or P3 maximum η sets can be stored, which are processed from the lowest level.

Connected to the buffer memory areas P _ik are the adders A1, A2 or A3 which, for the respective motion system, form the sum of the execution times t _{ik of} the sentences obtained in the buffer P1, P2 or P3.

The summation times are fed separately to the comparator VG according to the motion system. This gives to the following evaluator BW the information which of the motion systems has the highest, the lowest and the middle execution time tu of the buffered sets.

The information contained in the sentences or the buffer memory areas P _ik also information about continuous-path operation are linked by motion system separated via the AND gates U1, U 2 and U3. The information thus obtained that all the stored sets contain or do not contain continuous-train operation is fed to the evaluator BW as a path control operating signal B1, B 2 or B 3. The evaluator BW supplies the control coding for the selector SL and the distributor VT according to given criteria and thus determines which of the motion systems is to be supplied with a new processed set.

The criteria of the evaluator depend, for example, on whether all movement systems must be treated equally.

Referring to Fig. 3, an evaluator BW is shown for three equal-ranking independent motion systems. The path control operation signals B1, B2, B3 are applied to the selectors SL1, SL2, SL3. The comparator VG! Ibles, as comparison signals, the signals S _n -, - ,,,, S ^ e, S _ma x, which control a corresponding selector SL1, SL 2 or SL3. The outputs of the selectors SL1, SL2, SL3 and the threshold signal S _G are fed to the decoder D whose output controls the selector SL4, to which the comparison signals S _m j _n , S _m itt _e , S _{max are} applied. The output of the selector SL4 represents the output of the evaluator BW.

The comparison signals S _m i _n , S _center , S _max from the comparator VG contain the coding of the motion system with the smallest, the mean and the largest sum of the execution times t * of the sentences. The threshold signal Sq is additionally transmitted by the comparator VG. It signals whether the largest sum of execution times has exceeded a given limit. The path control operating signals B1, B2 and B3 are output from the outputs of the AND gates U1, U 2 and U3 to the selectors SL1,

SL2 and SL3 laid. The selectors SL1, SL2 and SL3 select according to their applied coding (S _m in / S _m \ _t e, S _ma x) the corresponding path control operating signal B1, B2 or B3 and supply it to the decoder D. The decoder D operates, for example, according to the truth table according to Table 1 and controls the connected selector SL4 so that it selects the signal indicated under "OFF." With these signals, the selector SL and the distributor VT can be controlled directly.

The control of several independent motion systems with undisturbed continuous-path operation is thus ensured such that primarily the sentences of the motion system are processed, the sum of the execution times is the lowest.

All sets must be traversed in continuous-path mode.

The priority determination is advantageously carried out in each case before the start of processing of each sentence and can be updated if necessary.

If all the buffers of the motion control systems in the path control mode are filled or the sum of the execution times exceeds a predetermined limit value, motion systems not in continuous-path mode can be operated with the processing of sentences.

Claims (3)

Invention claim: A circuit arrangement for controlling a plurality of independent motion systems, wherein each motion system has a part program memory and a buffer memory for a fixed number of blocks, comprising a function generator for batch processing, buffers for the execution times of the buffered sets and AND gates for the path control operation information of the buffered sets , characterized in that the workpiece program memories (S1, S2, S3) are connected to the function generator (FG) via a selector (SL), that an arithmetic logic unit (RW) is connected downstream of the function generator (FG) for calculating the execution times of the processed sets, in that the buffer memories (P 1, P 2, P 3) of the movement systems are connected downstream of a distributor (VT) connected to the arithmetic unit (RW), that the comparators (VG) have the summers (A 1, A2, A3) of the execution times of the buffered ones Phrases of each movement system are led that one with specifiable Kri the evaluation result leading output of the comparator (VG) and with the outputs of the AND gates (U 1, U 2, U3) for the path control operating signals (B 1, B2, B3) is connected, and that an output of the evaluator (BW) to a control input of Selektros (SL) and to a control input of the distributor (VT) is performed. 2. Circuit arrangement for controlling three equal-ranking independent motion systems according to item!, Characterized in that a comparison result from the comparator (VG) within the evaluator (BW) split into a limit signal (Sq), a first signal for the smallest (S _min ) , a second signal for the middle (S _center ) and a third signal for the largest (S _maii ) sum of execution _times that the path control _{operating signals} (B 1, B2, B3) to a first, second and third selector (SL 1, SL2 , SL3), that the first signal (S _min ) with a control input of the first selector '(SL 1), the second signal (S _center ) with a control input of the second selector (SL2), the third signal (S _max ) with a control input of the third selector (SL3) and all three signals with a fourth selector (SL4) in that a decoder (D) is acted upon on the input side by the limit value signal (Sq) and connected to outputs of the first, second and third select lines (SL1, SL2, SL3) and is connected on the output side to a control input of the fourth selector (SL4), whose output represents the output of the evaluator (BW). For this 3 pages drawings Field of application of the invention The invention relates to the field of digital control technology, in particular to numerically operating program controls. The invention is applied where, in the technological process, a numerical control simultaneously controls several independent motion systems. Characteristic of the known technical solutions From DE-OS 2237 311 a numerically controlled machine tool with a multi-axis path control is known which receives numerically encrypted control information from a moving record carrier having a control logic for data decryption and distribution, and stored in the control movement information decrypted several working memories are supplied for processing , In machine tools of this type, control information stored in sets on the recording medium is generally read out and distributed among a plurality of main memories, from which information is processed blockwise in order to process the decrypted, transcoded or converted information. After completion of a block a new block is called. The problem arises here that the new sentence is not available quickly enough. As can be seen from DE-OS 2237 311, by standing still the controlled axes of the machine tool on the workpiece surface annoying clearance marks and / or increased tool wear, chatter marks, etc. arise. To avoid this, it is known to provide buffer memory between the data distribution logic and the random access memories, in which the decrypted information of the next set is stored between them and is immediately callable when a set has been processed. The next block is already read into the buffer memory during execution of the previous block. In special cases, such as the process of small railways at high speed, it may in spite of the aforementioned measure to the absence of the next sentence come and thus to the o.g. Effects on the workpiece surface. This is because the processing time of the subsequent set exceeds the processing time of the set currently being executed. The processing time can not be reduced below a certain level. It is known from WP G 05 B / 284581 4 a circuit arrangement for undisturbed continuous-path operation in workpiece machining, in which not only a set, but several prepared sets are buffered. The number of buffered sets can not be increased arbitrarily because there are limits to the memory space within a numeric control. In order to prevent effects of the contradiction between preparation time and execution time of the blocks on the workpiece, a corrected path speed is calculated if necessary. For this purpose, the sum of the execution times of the stored sets is determined by a summer, which is consulted in the present, indicated by a corresponding signal of an AND gate, web control operation of all sets for calculating the correction factor for the web speed. The im