SU1603347A1 - Method and apparatus for shaping pulse sequence for stepping motor control - Google Patents

Abstract

The invention relates to automation and computer technology and can be used for the flexible software control of a stepper drive of the process equipment. The purpose of the invention is to expand the field of application by using stepper drive contour control systems and improving the stepper drive accuracy. The goal is achieved by forming a certain sequence of actions when loading a programmable timer counters and introducing additional elements into the motor control device. The device in accordance with the proposed method allows to regulate the time intervals, and thus avoid frequency failures and thereby increase the accuracy of the drive, which is expressed in increasing the accuracy of maintaining the frequency of control pulses of each of the motors. 2 Il.

Description

The invention relates to automation and computing and can be used for the flexible programmed control of the stepper drive of the process equipment.

The purpose of the invention is to expand the field of application by using stepper drive contour control systems and improving the stepper drive accuracy.

FIG. L is a block diagram of the device; figure 2 - timing charts of his work.

When interpolating spatial trajectories using a drive based on stepper motors, in order to improve the dynamic characteristics of the drive, as well as to ensure the stability of the contour speed (technological requirement, for example, during welding), it is necessary to maintain with high precision the speed of movement 1 along each of the coordinates, and therefore and frequency of control pulses. In the absence of regulation of the time interval dp reload values

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After the next interpolation segment is processed into the corresponding counters, the next section of the engine will begin to work out after a period of time independent of the current frequency of the control pulses. This leads to a failure of the frequency of the control pulses on each of the motors and the drive, and in turn increases the error in working out this interpolation region. In addition, when the engines operate at a frequency higher than the frequency of the pickup, such frequency failures can lead to step loss and. even to stop the engine. The regulation of the time interval allows you to avoid frequency failures and thereby increase the accuracy of the drive, which is expressed in increasing the accuracy of maintaining the frequency of control pulses of each of the motors, increasing the accuracy of maintaining the resulting speed of movement on each of the interpolation sites, and improving the accuracy of testing given zlacheni movement as for each of the coordinates, and the resulting movement.

The device contains .programmable three-channel timer 1, element OR 2, D-flip-flop 3, pulse counter 4, switch 5, one-shot 6, first 7 group of keys, group IS elements NAND, winding 9 stepper motor, group Y1yuy 10, sources 11 voltage, a group of power diodes 12, a voltage source 13, a group of power diodes 14. The device operates as follows.

In accordance with the method of forming a pulse sequence, the counters of the channels of the programmable three-channel timer 1 load the values of the coefficients (M) of the dividing units of the clock frequency and the value per unit

less than the constant corresponding to the number of pulses that must be applied for jibing a stepper motor. On the control bus to the device, signals of the initial installation of the trigger 3 and the direction of rotation are issued.

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 After permitting the work at the output of the counter of the first channel, 55

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a sequence of pulses

the frequency of which is determined by the dividing rate of the clock frequency. This

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counter of the second channel, working on the subtraction. For zeroing the counter. The second channel is monitored in monitoring or interrupting mode. After zeroing the counter of the second channel, a pulse appears at the second output of the timer, which sets the corresponding state of the D flip-flop 3. At the same time, the first and second channels of the timer counters are disabled and the third channel is enabled. During the time interval between the zero channel impulse of the second channel and the impulse appearing on the third output of the third channel, new values of the division factors and the constant are loaded into the timer counters. The appearance of a pulse at the output of the third channel returns the D-trigger-3 to the initial state. In this case, the operation of the counter of the third channel is prohibited and the operation of the counters of the first and BTOjporo is permitted. channels. Thus, the load time of new values in the channel counters is regulated by issuing a missing pulse for a stepper motor with a frequency corresponding to the frequency of previous pulses. The outputs of the first and third channels of the timer are connected to the inputs of the element OR 2. A sequence of pulses coming from the output of the element OR 2 sets certain combinations of connections on the outputs of the counter 4 pulses. Switch 5 according to this combination and signal. The direction of rotation sets the combination of signals corresponding to the forward and reverse rotation of a stepper motor. From the output of the switch 5, the signals arrive at the input of the elements AND-HE 8 and are gated with the signal supplied to the input of the elements AND-HE 8 from the one-shot 6, which determines the duration of the control pulses arriving at the motor. The pulse duration is equal to the time of the forked winding mode of this stepping motor — and is determined by. value and features of a particular stepper drive. The signal at the output of the AND-HE elements 8 opens the keys 10, which, by electronically forming the windings 9 of the stepper motor, supply the increased supply voltage from the source 11 through the isolating

diodes 12 to windings 9, thereby locking isolating diodes 14.

The signals supplied from the switch codes 5 to the inputs of the 7, open them, thereby connecting the corresponding windings 9 to the voltage sources 1 i and 13. At the end of the force forcing determined by single-stage 6, the output of the IS-HE elements 8 sets a signal that locks the keys 10, the supply of the increased voltage from the source 11 stops, and to the windings 9 through the disconnecting diodes 14 from the source 13 The nominal supply voltage is supplied.

 The proposed device allows software acceleration and deceleration of a stepper motor according to any given law. If it is necessary to change the frequency of the control pulses on each engine step, then the unit of the second channel of the timer is loaded into the counter, and the corresponding values of the clock frequency division coefficients are loaded into the first and third channels, and the number of more than. in the counter of the third channel, and during braking, the reverse actions are performed.

Claims (2)

1. A method of forming a sequence of pulses for controlling a stepper motor, which consists in determining the frequency and number of  control pulses, distribute a sequence of control pulses across the motor windings, amplify and feed these pulses to the motor, characterized in that, in order to expand the field of application . Due to the possibility of using stepper drive contour control systems and increasing stepper drive accuracy by eliminating the frequency of control pulses when changing frequency values during contour control, a pulse number is applied to the motor in which the number of pulses is one less than the number of steps required for practicing a given displacement, the missing impulse is fed to the engine after a delay equal to the pulse period of this sequence. 15 20 Q 25 30 40 45 50 55 j and, when implementing the contour control, each subsequent value of the frequency of the control pulses is set within the delay time and each subsequent value of the number of control 11X pulses is set within the time interval from the beginning of the count of the number of pulses of the current sequence to the moment it is fed to the engine missing momentum. 2. A device for forming a sweat pulse train for controlling a stepper motor, which contains a programmable timer, a pulse counter, the bit outputs of which are connected to the information inputs of the controller, a group of AND-NOT elements, the first inputs of which are connected to the corresponding outputs of the switch and the information inputs the keys of the first group, the control inputs of which are connected to the combined terminals of the first and second voltage sources, the outputs of the first group of keys are connected to the first leads of the windings stepper motor, the second terminals of which are connected to the cathodes of the first and second groups of the diodes, the outputs of the H-NE groups are connected to the information inputs of the 1 key of the second group, the control inputs of which are connected to the output of the first voltage source, and the outputs to the anodes Diodes of the first group, characterized in that, in order to expand the field of application, the element OR, D-flip-flop and single-oscillator J are introduced. The first input of the element OR is connected to the output of the first channel of a three-channel programmable circuit. measure and. to the input of the second channel account control, the second input of the OR element is connected to the code of the third channel and the R input. the trigger, the D input of the D-flip-flop is connected to the output of the second channel, the D- and C-inputs of the D-flip-flop are connected to the control bus, the forward output of the D-flip-flop is connected to the control inputs of the first and second channels of the three-channel the programmable timer, the inverse trigger output is connected to the control input of the third timer channel, the one-shot input is connected to the output of the ISH1 element and to the input of the pulse counter, and the one-shot output is connected to the second inputs of the AND-HE group. Phie.1    rziE