DE2225401C3 - Device for controlling the output of a servomotor - Google Patents

Description

as an answer to a single and complete phase discriminator "; the command signal

gen, stored in the command signal register (62) and compared with one another, wherein

command are in operation. 40 by a fixed between the two signals

2. Device according to claim 1. that the signal shaper (72.112) is called from which is converted into an analog Cileich voltage a monostable multivibrator (112) is converted. When the bc'dcn to the discreet on the other hand, a pulse width equal to half of the signals applied to the Pe- minator has the same free period generated by the Bezusjswelle. 45 sequence, then due to the non-exist-

3. Device according to claim I. characterized in that Phascr .-. Mtcrschieii-js kc ^; n FehLrsLni c. indicates that the bit levels in the digital register zeuni.

(62) are binary-coded bit levels and the grain- The known device and the known system-

parator (70, 110) with each of the bit levels in the digester have the decisive disadvantage that the

talrcgister and the corresponding bit levels in the 5 "counting sequence at first completely to the end and the analog

Digital counter (64) is connected to a clock signal error signal in the closed servo system only on

at the identity of the bits in the register and the zero must be brought. before the following

Corresponding bits in the counter and another which can be included in the command signals.
Clock signal after a counting sequence of the counter Furthermore, DigitaF-Analog-Dekodicrsysteme bc-

tiach the first clock signal to be generated. 55 knows. those with pliascnabhiingigen scrvosysiemcn.

4. The device according to claim 2 are thereby compatible (USA. Patents 3,175,138 indicates that the signal shaper (72.112) and 3 078 400). Such devices work Flip-flop (72), which is generated by the one ilen / vvci brought into Pha.sc control signal ^, that from the comparator (70, 110) coming from a Scrvogcrät for setting an out-fact signalc set and used by the other of the fio gabeoryans, the several one be-clock signalc is reset by the number of output setting items limited in phase in cyclic brought command signal waveform to result. Folrc can take. The output settings can

ncn z. B. the rotational positions of a shaft or axis

cut, which is defined by the phase designation of the

The invention relates to a device for stone-wave shapes that can be clearly defined.

I of the output of a servo motor with a zy- If you wish you could have any number of

- • h controlled digital counter, whose Au ^ garn- rotations of the shaft obtained by the

periodic reference waveform with a Frr wave repeatedly receiving commands to each of the turntable

they should be taken in sequence. While or input control given to such a system ; rsignal for only one position of the shaft is unambiguously called is, however, by appropriately programming the commands, it is possible to di </ aborted shaft . «A specific number of complete revolutions up to / u of the characteristic rotary position of the shaft to be carried out. This process enables a very precise movement of an object.

The advantages achieved with the invention are, in particular, that as a result of the input of data for any phase in the ZühlzyUlus of the counter Bclehlssignale immediately after their presence can be passed on to the servo motor, thus increasing processing speed to achieve accruing and entered data than was previously possible in known systems is. In addition, this input type of Oa-

ζ. B. a recording pen or a strip, kill a lovely simplified structure of the electronic

will not be. The phased Wellcnloim can also be used to make a resolver position in a linear grouping of output positions that occur in order.

In the known devices, the two control signals brought into phase represent waveforms, which are generated by two digital counters, these counters simultaneously and at the same speed as well as with a firm, the Ru. ^ 'nbeliehung Differer.-tiaizahlvveri corresponding to the wave forms being controlled. Inserting a new control signal from the digital source requires that both counters are brought to a standstill, a new command is inserted into one of the counters and Then both counters can be put into operation at the same time by a further command. Inserting new Commands and maintaining phase discrimination require that at the end of an even number sequence and after the output member that before has reached the controlled position. the counters are stopped. Therefore, the error jynal in the Servo loop and the torque of the servo motor between each command back to zero. With such Achieved circuit that gets by with a few electronic components, so that a Schallungsaui'wand will be obtained in an economically favorable ratio.

An embodiment of the invention is shown in the drawing and will be described in more detail below explained.

It shows

F i and 1 a perspective view of a Diüifil analog drum polishing system, in which the in accordance with the invention Device used wi: J.

2 shows a schematic block diagram of an exemplary embodiment of the device for the curve> chreiher- or plotter system of FIG. 1.

F i g. 3 is a block diagram in which the input elements the device according to FIG. 2 are shown in greater detail, and

Fig. 4 is a schematic block diagram of a further implementation game for the plotter from F i g. 1 specific device.

The invention relates to a device for controlling digital-analog systems in context with a phase-sensitive servo system for precise Positioning an Ausü.abctiliedev The tax

cl.cn systems is noticeable disadvantageously that it is especially designed so that a rotary

always has to go back to zero. if high position accuracy together with ue-

know!
the

precise work is required.

no count output

45

Control signals for any phase
follow and at any position d:
member can be introduced.

It is the object of the invention to provide a device create the phase control signals to dwell in generated by a phase-sensitive analog scrvo system, at any phase of the counting sequence and at any position of the output member can be entered continuously to make the system accurate and responsive steer.

The object is achieved according to the invention by one with the digital counter and the error signal register connected comparator to compare the digital counts and the digital key signals and at each coincidence of the digital count and the digital key signals, coincidence signals to be generated by a signal formula which is connected to the comparator and to the Ko'tizidenzsignalc responds to a periodic command signal form which has the same period or frequency as the reference waveform and which is Phase relationship with the reference tool which are clearly related to the Bcfehlssignal in the register where the comparator and the signal former always work together. if they are to continuous Generation of the periodic command signal air. Answer to `` a single and complete, instruction stored in the error message register are in operation.

65 bares output link is moved between a cyclical sequence of starting positions and therefore x <ch is particularly suitable for Scrvo systems with rotatable · η Λ11 * - gaiiiis links. However, the device can also be used in systems that use e.g. B. have a resolver as an output member that is linearly displaceable between positions that are mutually related by a cyclical Bcfehisfolue.

Although the invention can be used in many ar.cn ve mi scr.ox systems, it is described below in an embodiment in connection with a drum plotter system, as the ·· in Fig. is shown graphically. The entire system 10 consists of the drum flotter and the computer 12. On the drum plotter 14 or curve plotter, the delicty outputs from the computer 12 are recorded. The computer ) 2 can either be an ordinary computer or a special computer that carries out the desired data processing operations and the inputs z. B. is supplied via a storage tape 16. The separate information channels and the Funk! any of the computers are not part of the invention and are therefore not described in detail. For the purpose of understanding the finding, it should only be said that the computer 12 represents a digital control signal source which supplies the digital information that is to be transformed and visibly displayed on the drum plotter 14.

This plotter 14 consists of the recording drum 20 with a chart paper 22 comes into engagement and it in Eängxrichtimg between the two on opposite srites of the

Drum 20 located receiving or; Mfwickclnden drums 24 and 26 moved back and forth. By means of Ril / cl (not shown) the fitting recesses located on the paper on the sides are engaged by the drum, so that a rotation of the drum results in a precisely corresponding displacement of the paper 22. The winding motors and slip clutches not shown in the drawings are located on the winding drum !! 24 and 26, in order to keep the paper; bits or segments stretched between the drum and the rollers under low tension so that the paper is properly unwound from or onto the winding roller when the plotter drum 20 is in one or the other is rotated in the other direction. Hin Hilfsstcuermoior 28, which is housed in the housing of the plotter 14, is connected to the drum 20 either directly or via an intermediate gear for the purpose of driving, so that the drum is rotated during the recording process, line writing or drawing pen 30 is in one low ^l: .n; fernung arranged from the drum to be able to perform small \ ertical movement. It is arranged on the displaceable carriage 32 and is brought into position on the carriage over the drum unit on which the paper 22 is located, so that a track or line 7 is produced on the paper 22 when the spring moves towards the drum 20 is pushed downwards. The carriage 32 can be displaced in the lateral direction with respect to the paper strip, specifically on two guide rails 34 which are let into the cichouse of the plotter 14. The displacement of the carriage 32 is controlled by a servomotor 40 which drives a toothed belt 42 which engages with the carriage 32 and extends over the guide pulleys 44 which are fastened to the housing of the plotter 14.

The drum plotter can therefore be equipped with three control or control axes according to the representation to which information must be supplied. to get an exact line on the To produce paper 22 in accordance with the digital data supplied by the computer 12. The one Steuerachsc sees in relation to the longitudinal movement of the paper 22. that caused by the rotation of the drum 20 and the marine motor 28 is called out. My second control axis is with the translation increase. the feather and the carriage 32 in the lateral direction across the paper 22 and the drum 20 in relation. the third axis relates to the pivoting movement of the spring 30 in the carriage 32, causing the spring from Recording paper can be lifted off or placed on this. Such pivoting movements can be controlled by a small electric solenoid built into cart 32 is. By appropriately controlling all movements related to the three axes according to the from Computer transmitted to the plotter via cable 50 becomes an exact line of the Digital data is created on the drawing paper 22.

The digital control device according to the invention is used to drive the servomotor 28 and the drum 20 in one control axis in order to bring the paper 22 into position precisely in the longitudinal direction during the recording event. Although the initial evveguni: the drum 20 is mainly a thrilling event. ¹ kai "tlu control device also for Lr / Eugen lateral translational motions of the characters spring 30 and the carriage are 32 is used.

In FIG. 2 is a schematic block diagram of the apparatus in plotter 14 shown in FIG (The rotary movement of the plotter drum 20 controls. In control signals supplied in digital form by the computer 12 represent a desired starting position of the Drum 20. You will be through the devotion

jo direction 60 given to a digital storage register 62, where the commands are temporarily saved. After a filling in the Hrfimiuiig is register 62 is an up and down binary counter. and the data provided by the add-on device 60 Zcichcninformalion. which indicates the direction in which the counter has to count up or down. and counts. which vary the total or number in the register. The ones that appear in the order in which they appear in the register Numerals correspond to those to be taken one after the other by the plotter drum 20 Target positions. If z. 13. the register 62 is an eight bit binary counter with a maximum count of 25h. so every value represents one of the 256 discrete clutches of the Ί lomnicl 20 represent every pulse added to the register corresponds to an instruction, the drum by approximately 1.4 to the next position in the cyclical sequence of Starting positions to thieves. Of course can be the number of discrete stents to be created according to the increased cn ode; reduced counting facility or scope of the register 62 or be restricted.

The control device also has a digital up counter 64th that has a binary counter capacity which is the same as that of register 62. For example, if register 62 is an S-bit binary counter, for example. so is the counter 64 also cm Achi-Bit-Ziihlcr. This Counter 64 is driven by a crystal-controlled clock generator 66 and runs continuously in the counting direction until the maximum number is reached. At the next clock pulse wild di'.s counter is set to zero from the maximum value and begins with a counting sequence. As long as the clock 66 continues to supply the counter 64 with pulses / u, one counting sequence follows the other. Between the register (> 2 and the, counter 64 licu.1 the dicital comparator 70. the counter reading by counter 64 constantly compares with the instructions stored in register 62. If the command and the count match or coincide. The comparator 70 generates a pulse, the with the counting sequence has a phase relationship that uniquely related to the instruction in register 62

stands' Theoretically, the counter generates a Counting sequence a full set of tiufeinande following control signals, in a binary or otherwise coded form. The one from the grain parator generated Koin / Idcnzimpuls 70 is dcmzufolgi

a phased clock signal that is phased Drawing stands'with the counting sequence that the debit position; the plotter drum 20 with respect to the fixed zeroing corresponds. If everyone except the hochsUvet If the bit stages of the counter 64 and register 62 i find coincidence, the comparator 70 a generates: a place v ».. IHO in the counting sequence or to a half counts depending on the first in the case of coincidence of all hits i '.' rten Inipul- cnen / ^ t-iten Impiii ·

Both pulses are sent to a shaping or equalizing circuit 72 transferred, which in one embodiment is a flip-flop that is released by the first »He set impulses and reset from the second impulse will. This circuit 72 generates cmc bleue.-lignal-Wdlenform, the dnc rectangular shape of the same frequency as the number sequences of counter 64 And has a phase relationship to the number sequences. which is directly proportional to the command in register 62.

The command signal waveform is given with a Bc- The waveform used by the up counter is a phase-sensitive analog scrvo system is generated, which contains the servo motor 28 required for aligning the plotter drum 20 The reference waveform in the embodiment of the present invention using a binary Au counter used is derived from the most significant bit level of the counter. The output of the bit stage is a square wave of a frequency that a multiple of the counting or pulse rate of the clock 66 and is the same with the frequency of the counting sequence. According to the statements The square wave represents a time scale f, fro that phased as a basis for further ones Signals in the system. The square wave is passed through a low pass filter 74 which has an output vif shows, on the Jie basic speed ^ the Square wave as a sine function with a fixed phase reference to the reference waveform appears.

The second most significant bit level of Zahler_M also has an output which is a square wave of twice the fundamental frequency derived from the filter 74 delivers. The square wave of the A wave inverter runs through a higher frequency 80. so that the phase of the wave is changed by 180 °, and then a frequency divider 82. which increases the frequency by a factor of two Rectangular waves from the most significant bit level of counter 64 is reduced.

The fundamental oscillation of the square wc frequency divider 82 is tct by the TicBpaßfiltcr 84. The outputs of filters 74 and 84 are the 90-phase sinus and cosine waves, which have frequencies of the same size as the reference form and are used to excite the respective field windings of a coordinate converter 86 as feedback position sensors for The PloUer drum 20 is used. This Koordmatenwandler ■ »be sits a rotor winding to the ^{major <*} ™™ ^d | i rotation immediately nu of the shaft of the drum is located, and as a result of by the excitation von_ the filters 74 and 84 next sine and W waves, the output signal of the coordinate converter has a sinusoidal curve which has a phase relationship to the reference wave shape, which is proportional to the rotation division ^ of the plotter drum 20 Plotter drum 20 in ^ pYaY ^

Servo motor 28 is of conventional construction

art with closed loop. The befe

from the equalization circuit 72 and ^

treatment signal from the coordinate converter 86;

A phase detector 90 compared the emj e

lunRsfchlcrsignal generated, which is sent to e.ncn summ.er amplifier 92 and a power amplifier 94 which drives the servo motor 28 is given. A Molorlachomcter 96 loads the output speed of the servomotor and supplies it for summing the position error signal to the summing amplifier 92 is a signal for attenuating the operating value. The output shaft of the servomotor lies on the plotter drum 20 via an intermediate gear 98 If desired, one may be connected between the input device 60 and the summing amplifier 92 Pulse tachometer feed result, which when mixed with the operating value attenuation signal of tachometer 96 results in zero point deviation at constant acceleration.

It is an important feature of the invention that digital commands can be placed in register 62 at any phase of the count sequence drs 2 'counter 64 without a zero point error signal occurring in the servo loop. It is understood here that in the steady state with zero position deviation in the servo loop, the clock generator 66 and the counter 64 continue to run and generate the reference waveform, the comparator 70 and the compensation circuit 72 continuing to generate a control signal waveform. The phase relationship between the reference waveform and the command waveform remains constant and keeps the plotter drum 20 in the desired position. When a new command is transferred from the input device 60 to the register 62, the phase of the clock signals generated by the comparator 70 and, accordingly, the phase of the control signal waveform of the compensation circuit 72 are changed. The phase detector 9 ¹ O is not longer in equilibrium, is no longer phascngleich and provides an error signal energizes the servo motor 28 and the Plottertrommel 20 brings in the controlled or desired position. The feedback signal from resolver 86 causes an error signal to be reset to zero.

returns

The F i g. 3 shows a diagram of the timeouts and the components of the input device 60, whereby new control signals from the computer 12 in the consecutive process sequentially entered into register 62 at any phase of the counting sequence can without interrupting the counting sequences. Register 62 is shown as an up-down binary counter, via the input device 60, which has a flip-flop 100 and an AND gate 102, to the Computer 12 is switched. For the sake of clarity, it will now be assumed that the computer 12 individual or series of control impulses produced to the cumulative total in To change the up / down counter, although it is also possible is to load register 62 in parallel as desired. It is also assumed that signs have already been supplied by the computer 12 to the up / down counter to determine the direction of the Define impulse operation of the counter. 60 The clock generator 66, the binary up counter drives, is shown as a multi-phase clock and is also on the comparator 70 and the AND gate 102. The outputs of the multi-phase clock deliver non-overlapping pulses in phase-65 synchronized pulse trains. The output carrying the first phase is connected to the up counter 64 and the outputs carrying the second and fourth phases are applied to the comparator 70. The die

409 684/21;

The third output carrying the phase is connected to the AND gate 102 . A control phase from the computer is stored in the flip-flop 100 until a pulse in the third phase sounds the AND gate to ΛΝ (ON) and feeds the up / down counter. It should be noted that the flip-flop 100 is reset for subsequent control pulses each time a control pulse is passed to the counter 62. The frequency of the clock pulses in each pulse train is the same and is chosen to be significantly higher than the maximum output frequency of the pulses coming from the computer. If z. For example, if the maximum output frequency of the computer is 2OkII /, then each phase of the clock generator 66 can operate at a frequency of 2 MUz. A system operating with these frequencies would allow that, in general, no more than two digital counting pulses could be given from counter 64 to counter 62 during each counting sequence.

The multiphase outputs of the clock :. 66 allow the input information stored in flip-flop J 02 to be passed into counter 62 without interrupting the counting sequence. It is thus possible to make comparisons between the counters 62 and 64 in any phase of the counting sequence without the data in either counter changing during the comparison process. However, in order to avoid that an input pulse from the comparator 70 is not encountered if a pulse is delivered with the same count and with the opposite course of the counters, the second and fourth phases of the clock generator 66 switch the comparator 70 to "on" before and after the third phase charges the counter 62. Although the double gating of the comparator 70 generally generates two consecutive pulses at each flip-flop input 72 during a counting sequence, only the first of these pulses changes the state of the flip-flop.

It must be emphasized that the two outputs of comparator 70 are each connected to the setting and reset inputs of flip-flop 72 are. The output of the one located at the setting input Comparator is the coincidence circuit of the corresponding bits in all in the binary counters 62 and 64 bit levels included. The output connected to the reset input supplies the coincidence signal when the corresponding bits coincide in all but the most significant bit levels and the bits in the most significant bit levels are not the same. Thus, the flip-flop 72 in temporal, 180 ° amounting interval during each counting sequence on and reset. Here takes the square wave output of the flip-flop indicates the period and frequency of the counting sequences.

Thus, it will be understood that the phased clock pulses which operate counter 64, comparator 70, and gate 102 allow the input control pulses to be applied at any time during the count sequence and the application and counting to be coordinated that they do not interfere with the comparison process. With these features, control signals can be sent to the servomotor immediately after they are available, in order to achieve a higher data processing speed than was previously possible in known systems, in which the counting sequence was first brought to an end and the analog error signal in the closed semiring line system must be brought to zero. before the subsequent control signals are accepted. The faster data processing system according to the invention results in improved data output on the recording paper strip 22.

In FIG. FIG. 4 shows a further embodiment of the control device according to the invention for installing the closed scraping line system with rotating plotter drum 20. Here are the same as the exemplary embodiment in FIG. 2 similar components also have the same references. Also in the example of FIG. 4 the reference waveform and the Stcucrwcllcnform are generated by a comparison of the count in the up counter 64 with the instruction in register 64. However, the comparator 110 differs slightly from the comparator of FIG Coincidence signal is generated only once during each counting sequence when all digits in register 62 coincide with the corresponding digits in counter 64. The coincidence signal is applied to a compensation circuit 112 , which is a precision monostable level vibrator which produces an output pulse of a pulse width and duration equal to that of the counter 74 counting sequence. By generating the coincidence signal during each count sequence at cinc ^r phase of the sequence that is directly related to the instruction in register 62, the output of multivibrator 112 becomes instruction waveform, a clock wave generated in relation to 711 the instruction in register 62 most significant bit stages of counter 64 derived reference waveform is phase modulated. The biphasic waveforms are then used in the phase sensitive servo system to position the plolt drum 20 .

The control or command wave firm is applied to the phase detector 90. The reference waveform 64 generated by counter 64 is applied to a low pass filter 120 which derives the fundamental waveform of the waveform. The sine and cosine signals exciting the field windings of the resolver 86 are generated by the fundamental wave with the aid of a circuit 122 which has a lagging phase shift of 90 °. With the components and the operating mode of the closed servo ring line system of FIG. 4, the positioning of the plctter drum 120 is achieved in the same way that was described with reference to the exemplary embodiment shown in FIG.

Of course, numerous changes and substitutions can be made in the exemplary embodiments presented without departing from the scope of the invention. Although the register 62 and the counter 64 are designed to receive control signals encoded in binary form, e.g. B. other forms of coding control such as decadic binary coding can be used as long as a phase-adjusted comparison signal can be generated. Also, in spite of the counter 64 described as an up counter, it is only necessary that the counter runs either up or down cyclically in the same direction, namely in a complete count in each counting cycle. Accordingly, the invention described in several exemplary embodiments is not to be regarded as being limited by them.

1 sheet of drawings

Claims (1)

1 2 a "" ... üiiciu ran, which is a sub-line of the digital I claim. Counting speed, with a digital recorder 1. Device for controlling the output gnnlregister, the oscillation of which is a single, complete servomotor with a cyclically controlled digital command signal for the discrete positioning of the digital counter, the output of which is a periodic 5 servomotor output for the temporary memory reference waveform with a frequency that receives tion until a Another discrete position is due to an underfrequency of the digital counting speed, and with a phase-sensitive mode, with a digital master signal register, gate control, which is connected to the servomotor and the D \ v. \ - whose input is a single, complete valley counter and a plias detector miss signal for the discrete positioning of the scrio, which is based on the pull waveform and the bevel motor output for the temporary memory miss signal waveform for positioning. Servorung is received until another discrete position molor output is commanded according to the phase relationship and responds with a phase sensitive periodic waveform. chen motor control that works with the servo motor There are already bearing control devices with a and the digital counter and a servomotor, which is controlled by a phase discriminator. Has phase detector that is controlled to the reference and the position of a machine segment, lenform and the command signal waveform for z. B. the tool of a machine tool, and Positioning of the servo motor output according to which at the same time adjusts the setting of a resolver, what Plvise relation of the periodic waveform is thereby achieved. that the State. · w. ^ kinngen des responds, characterized by a 20 Rcsolwrs on two circuits for generating pha- with the digital counter (64) and the command shifted rectangular switch. mgunycn ange ^ chios- signalregislcr (62) connected comparator (70. sen ■ -.iηd and that the 110). around the digital counts and the digital oscillation via a harmonic filter len command signals to compare !! and around at each and as an actual signal of rectangular shape of the " the coincidence of digital counting and the discriminator for comparison with the rectangular digital command signals coincidence signals to generate setpoint signal is supplied (German Ausle ^ e- testify, by a signal shaper (72.112), the writing 1 249 977) is connected to the comparator and on the next is from the USA.-Father,; -; script 3! 73 00! Coincidence signals responds to a periodic an electronic automatic control system ßefehlssignalwcllenfonii, the same 30 known that numerically the Bevvegimtis- Period or sequence like the reference waveform sequence of a machine tool controls what thereby has and is accomplished in phase relation with the reference that the input data over lenform, which is entered in response to the command signal in the register, an intervening storage register stcr is clearly related, wöbe, become the comparator and remain in the memory for so long, both (70, 110) and the signal conditioner (72. ί12) always 35 previous command block is completely executed: then work together if they get to continuicr- only then do the The normal generation of the periodic command signal stores data in the main memory reL'iMcr. Ir,