JP4133080B2 - Closed loop pulse train control method and apparatus for stepping motor - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a stepping motor closed loop pulse train control method capable of rotating a stepping motor in a state most suitable for an inertia load in a closed loop driving of a stepping motor and realizing smooth driving without step-out or vibration. And the device.
[0002]
[Prior art]
A stepping motor has a cylindrical stator having excitation teeth that are alternately excited to N and S at predetermined intervals on the inner circumferential surface, and rotates inside the stator, and N and S are alternately excited on the outer circumferential surface. In the case where the polarity of the adjacent rotor teeth and the excitation teeth are different, they are attracted to each other, and in the case of the same polarity, utilizing the property of repelling each other, By successively switching the polarity of the excitation teeth, the rotor is continuously stepped.
[0003]
In such step drive, the rotational torque is generated by magnetic energy generated between the exciting tooth of the stator excited by the exciting coil and the rotor tooth of the rotor. In order to continuously rotate the rotor in steps, the polarity of the excitation teeth adjacent to the rotor teeth in the rotation direction must be switched prior to the rotation of the rotor so as to continuously pull the rotor teeth. The angle between the position of this rotor tooth and the preceding excitation tooth is a deviation. That is, in order for the stepping motor to continue the step rotation, an “excitation advance angle” is required between the excitation position of the stator and the rotor position, and this “excitation advance angle” is the deviation. In the case of deceleration, on the contrary, the polarity of the excitation tooth close to the rotor tooth is switched so as to be delayed with respect to the rotational speed of the rotor, and the brake of the rotor is applied. In other words, the rotor is decelerated by reducing the advance angle.
[0004]
Now, a stepping motor is generally used to move a load connected thereto from point A to point B. In this case, the stepping motor is accelerated until reaching a constant rotational speed, and after reaching the constant rotational speed, the so-called trapezoidal drive is performed in which the rotational speed is maintained and decelerated immediately before point B. In such trapezoidal drive, the rotor of the stepping motor starts step rotation from the stopped state, reaches a constant rotational speed, maintains this speed, and then decelerates and stops. At startup, a large rotational torque is required to rotate the rotor, and at the time of deceleration, a large deceleration torque is required to apply the brake. Such torque is generated by the magnetic energy between the stator and the rotor as described above.
[0005]
As described above, each exciting tooth of the stator is excited to N or S by the winding current flowing in the exciting coil, but the “winding current rise / fall time” caused by the inductance of the exciting coil is switched between excitations. It is something that delays. The higher the rotation speed, the larger the ratio of the “winding current rise / fall time” to the excitation cycle. If the rising time of the winding current occupies one cycle of excitation, it takes time for the rotating torque to rise. In addition, the residual current after switching the excitation (this continues to flow in the same direction to the excitation coil for a very short time, even though the switching of the drive control unit has changed and the direction of the excitation current flowing to the excitation coil has changed. (I3) in FIG. 1 (a) indicates the current to be applied, and acts as a deceleration torque on the rotation of the rotor and acts in a direction to reduce the rotation torque.
[0006]
Now, when rotating a stepping motor, the rotor cannot follow the excitation switching from the drive control unit, especially at startup or acceleration / deceleration, or the natural frequency and excitation frequency of the drive system and device including the stepping motor are When they substantially coincide, resonance occurs, and the deviation of the rotational position of the rotor with respect to excitation switching becomes too large, causing step-out (a phenomenon in which the rotor does not vibrate due to vibration) or vibrates.
[0007]
To start or accelerate / decelerate the stepping motor without stepping out or vibrating, the excitation switching speed of the excitation winding of the stepping motor is controlled so that the rotational position of the rotor is kept in a range that can follow the excitation of the rotor synchronously. Must.
[0008]
Therefore, in the conventional method, the higher the inertia load, the lower the start speed on the command pulse generator side, or the drive mode that lowers the acceleration / deceleration rate or lowers the torque required for acceleration / deceleration. The tone has been eliminated. In addition, a stepping motor having a large current capacity and a driving device (in other words, a stepping motor having a higher power) are selected to allow a margin for acceleration torque.
[0009]
In other words, in the conventional method, if the power of the stepping motor is not sufficiently large with respect to the inertia load, in order to avoid the step-out, the acceleration (deceleration) must be excessively reduced to accelerate and decelerate slowly. There was a problem that the time of one cycle had to be lengthened. On the other hand, in order to shorten the time of one cycle, it was necessary to use a stepping motor having a larger power than necessary.
[0010]
In addition, when the above problem occurs in the existing apparatus, it is necessary to replace the drive part itself, and it is very difficult to cope with it.
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described conventional problems, and is a stepping motor that can automatically adjust the control of the stepping motor with respect to the inertial load and can realize smooth driving without step-out and vibration. The task is to develop a closed-loop pulse train control method.
[0012]
[Means for Solving the Problems]
  “Claim 1” relates to a closed-loop pulse train control method for a stepping motor (1) according to the present invention, “a rotor position pulse (ENCP) indicating a rotor position of the stepping motor (1), and a drive controller for driving the stepping motor (2 ) To receive the primary command pulse (PGP) from the command pulse generator (4) and output the secondary command pulse (OUTP) to the drive control unit (2). In the closed-loop pulse train control method of the stepping motor (1) that switches the excitation sequence of the stepping motor (1) in synchronization with (OUTP),
(A) A lead angle side where a deviation between the secondary command pulse (OUTP) and the rotor position pulse (ENCP) is detected and the secondary command pulse (OUTP) is advanced with respect to the rotor position pulse (ENCP). And a predetermined deviation range defined by a predetermined deviation value on the delay angle side in which the secondary command pulse (OUTP) is delayed with respect to the rotor position pulse (ENCP), and a secondary command pulse ( OUTP) and the rotor position pulse (ENCP) are compared,
(B) The deviation isdeviationIf smaller than the predetermined range, the primary command pulse (PGP) is output as it is to the drive control unit (2) as the secondary command pulse (OUTP).
(C) When the deviation is advanced to the state where the secondary command pulse (OUTP) has advanced with respect to the rotor position pulse (ENCP) and is increased to a predetermined value on the angular side deviation, 1 from the command pulse generation (4) While holding the next command pulse (PGP)This is counted as a pool pulseThe secondary command pulse (OUTP) and the rotor position pulse (ENCP) are output as a secondary command pulse (OUTP) to the drive control unit (2) by outputting a high-speed pulse in the direction opposite to the primary command pulse (PGP). The excitation sequence of the drive control unit (2) is temporarily pulled back until the deviation from is reduced to a predetermined amount,
(D) When the deviation has expanded to a predetermined value on the delay angle side deviation in which the secondary command pulse (OUTP) is delayed with respect to the rotor position pulse (ENCP), the command pulse generator (4) While holding the primary command pulse (PGP)If there are any accumulated pulses, subtract them and store the difference, andBy outputting a high-speed pulse in the same direction as the primary command pulse (PGP) as a secondary command pulse (OUTP) to the drive control unit (2), the deviation between the secondary command pulse and the rotor position pulse becomes a predetermined amount. The excitation sequence of the drive controller (2) is temporarily advanced until it is reduced,
(E) The absolute value of the predetermined deviation value on the delay angle side when the secondary command pulse is delayed with respect to the rotor position pulse is the advance angle side when the secondary command pulse is advanced with respect to the rotor position pulse. By setting the deviation smaller than the absolute value of the predetermined deviation value, the deviation value on the lead angle side where the secondary command pulse has advanced with respect to the rotor position pulse and the secondary command pulse with respect to the rotor position pulse The predetermined deviation range determined by the predetermined deviation value on the delay angle side in the state of being delayed is made asymmetric with respect to the deviation 0, and the deviation predetermined range is narrowed to limit the vibration of the rotor of the stepping motor.It is characterized by that.
[0013]
  In the method of the present invention, the stepping motor (1) is driven so that the deviation between the primary command pulse (PGP) from the command pulse generator (4) and the rotor position pulse (ENCP) is kept within a predetermined range. As in the conventional example, when the input speed of the command pulse input to the drive control unit with respect to the load applied to the rotor is too fast to follow the rotor, or vice versa, a step-out occurs. In the method, smooth driving without step-out or vibration can be realized by maintaining the deviation within a predetermined range.That is, by performing such processing, it is possible to realize smooth acceleration and constant speed driving by suppressing step-out during acceleration or deceleration or vibration during constant speed driving.
[0015]
  "Claim 2Is a further improvement of “Claim 1”,
(A) The rotor position pulse (ENCP) and the secondary command pulse (OUTP) are caused by a rapid speed change of the primary command pulse (PGP) or unevenness in the speed of the rotor position pulse (ENCP) generated when vibration of the rotor (1a) occurs. ) Reaches the limit of the specified range,
(B) A secondary command pulse (OUTP) that is sufficiently faster than the rotational speed of the rotor (1a) is output to the drive control unit (2) by a predetermined amount in the direction in which the deviation is reduced, and the excitation sequence is temporarily It is characterized by reducing the torque ripple caused by deviation fluctuations by attracting the rotor position and suppressing the vibration of the stepping motor (1). By performing this process, the step-out during acceleration or deceleration is reduced. Alternatively, smooth acceleration and constant speed driving can be realized by suppressing vibration during constant speed driving.
[0016]
  "Claim 3”Relates to a closed loop pulse train controller for a stepping motor (1) for carrying out the method of the present invention,“ a command pulse generator (4) for generating a primary command pulse (PGP) for driving the stepping motor (1), A drive control unit (2) that controls the drive of the stepping motor (1), an encoder (3) that is installed in the stepping motor (1) and outputs the rotor position as a rotor position pulse (ENCP), and a command pulse generator ( 4) is installed between the drive control unit (2) and takes in the primary command pulse (PGP) from the command pulse generator (4) and also sends the secondary command pulse (OUTP) to the drive control unit (2). OutputforA pulse train controller for a stepping motor configured with a pulse train interface unit (5),
  The pulse train interface (5)
(A) A lead angle side where a deviation between the secondary command pulse (OUTP) and the rotor position pulse (ENCP) is detected and the secondary command pulse (OUTP) is advanced with respect to the rotor position pulse (ENCP). And a predetermined deviation range defined by a predetermined deviation value on the delay angle side in which the secondary command pulse (OUTP) is delayed with respect to the rotor position pulse (ENCP), and a secondary command pulse ( OUTP) and the rotor position pulse (ENCP) are compared,
(B) The deviation isdeviationIf smaller than the predetermined range, the primary command pulse (PGP) is output as it is to the drive control unit (2) as the secondary command pulse (OUTP).
(C) When the deviation is advanced to a state in which the secondary command pulse (OUTP) has advanced with respect to the rotor position pulse (ENCP) and expanded to a predetermined angle side deviation, the command pulse generator (4) While holding the primary command pulse (PGP)This is counted as a pool pulseThe secondary command pulse (OUTP) and the rotor position pulse (ENCP) are output as a secondary command pulse (OUTP) to the drive control unit (2) by outputting a high-speed pulse in the direction opposite to the primary command pulse (PGP). The excitation sequence of the drive control unit (2) is temporarily pulled back until the deviation from is reduced to a predetermined amount,
(D) When the deviation has expanded to a predetermined value on the delay angle side deviation in which the secondary command pulse (OUTP) is delayed with respect to the rotor position pulse (ENCP), the command pulse generator (4) While holding the primary command pulse (PGP)If there are any accumulated pulses, subtract them and store the difference, andBy outputting a high-speed pulse in the same direction as the primary command pulse (PGP) as a secondary command pulse (OUTP) to the drive control unit (2), the deviation between the secondary command pulse and the rotor position pulse becomes a predetermined amount. The excitation sequence of the drive controller (2) is temporarily advanced until it is reduced,
(E) The absolute value of the predetermined deviation value on the delay angle side when the secondary command pulse is delayed with respect to the rotor position pulse is the advance angle side when the secondary command pulse is advanced with respect to the rotor position pulse. By setting the deviation smaller than the absolute value of the predetermined deviation value, the deviation value on the lead angle side where the secondary command pulse has advanced with respect to the rotor position pulse and the secondary command pulse with respect to the rotor position pulse The predetermined deviation range determined by the predetermined deviation value on the delay angle side in the state of being delayed is made asymmetric with respect to the deviation 0, and the deviation predetermined range is narrowed to limit the vibration of the rotor of the stepping motor.It is equipped with a function to
[0017]
In the present invention, as the method of maintaining the deviation during acceleration, the pulse input to the drive control unit (2) of the primary command pulse (PGP) is temporarily cut off to reverse the direction of the primary command pulse (PGP). Is input to the drive control unit (2) to temporarily reduce the deviation between the rotor position pulse (ENCP) and the secondary command pulse (OUTP), and if the deviation falls within the specified range, the command pulse generator The primary command pulse (PGP) from (4) is output to the drive controller (2), and the stepping motor (1) is rotated as it is. At this time, the primary command pulse (PGP) whose output is suppressed to reduce the above-described deviation is held as a “dwell pulse”.
[0018]
In this way, during acceleration, the secondary command pulse (OUTP) is output to the drive control unit (2) in accordance with the rotation of the rotor (1a). However, if the rotor (1a) is still underaccelerated and the deviation is widened again, The deviation is reduced by the reverse pulse by the above-described operation. By repeating this pulse loop operation, it is possible to accelerate according to the inertial load and to avoid step-out during acceleration. (See Figure 4)
[0019]
Conversely, when the primary command pulse (PGP) from the command pulse generator (4) suddenly decelerates to the rotating stepping motor (1), the rotor (1a) commands the inertial load or rotor inertia. The rotor (1a) is not able to follow the normal deceleration, the secondary command pulse (OUTP) [This secondary command pulse (OUTP) is the primary command pulse (PGP) that passes through the pulse train interface (5) as it is It is output as the next command pulse (OUTP). ] May be overtaken.
[0020]
In such a case, the deviation between the secondary command pulse (OUTP) and the rotor position pulse (ENCP) is temporarily output in the same direction as the rotation direction of the rotor (1a) (the direction of the primary command pulse). Shrink. Accordingly, it is possible to perform deceleration without undue stepping out by repeating the pulse loop operation in the same manner as acceleration. (See Figure 5)
[0021]
Also, even when the deviation between the primary command pulse (PGP) and the rotor position pulse (ENCP) exceeds a predetermined value due to vibration during rotation, the same loop operation functions and the deviation can be reduced. As a result, the amplitude of vibration can be reduced.
[0022]
In a state where the rotor (1a) is rotating without vibration, the excitation and the rotor (1a) are uniformly maintained with a deviation, but once the primary command pulse (PGP) suddenly changes in speed or is disturbed. When the deviation fluctuates, the deviation increases or decreases around the deviation position that should be balanced, and as a result, "torque ripple acting in the acceleration direction" and "torque ripple acting in the deceleration direction" are superimposed on the torque required for rotation. Become.
[0023]
In the present invention, when the deviation reaches a predetermined value due to the vibration, the fluctuation range of the deviation that becomes the source of the torque ripple is reduced by the high-speed pulse, and the vibration is contracted. Further, in the present invention, the delay side deviation predetermined value (absolute value) is made smaller than the predetermined advance angle deviation value (absolute value) with respect to the deviation 0, that is, the advance angle deviation predetermined value is set to the delay side deviation centered on the deviation 0. By making it larger than a predetermined value and making it asymmetrical, the deviation fluctuation range is narrowed to improve the vibration suppressing effect.
[0024]
FIG. 3 is an explanatory diagram showing the relationship between the deviation and the predetermined deviation ranges (A) to (-B). 3A is a predetermined advance angle side deviation value, (−B) is a predetermined delay angle side deviation value, and inner part (a) is less than the advance angle side deviation predetermined value (A) due to the reverse high-speed pulse. (B) shows a state of being pulled back to a delay angle side deviation not more than a predetermined value (−B) (right side from (−B) in the figure) by the forward high-speed pulse.
[0025]
In the case of this embodiment, there is a deviation 0 (a delay angle retracting position or its vicinity) on the delay angle side deviation predetermined value (−B) side, and the advance angle side deviation predetermined value (A ) And the delay angle side deviation predetermined value (−B) are located asymmetrically.
[0026]
When the deviation exceeds a predetermined deviation range (that is, the advance angle side deviation predetermined value (A) or the delay angle side deviation predetermined value (-B)), the step-out occurs. Therefore, if the deviation tries to exceed the predetermined value (A) on the advance angle side within the predetermined deviation range (A) to (-B), the primary command pulse (PGP) is used as the secondary command pulse (OUTP) as it is. Output to the unit (2) as it is is temporarily interrupted, and a reverse high-speed pulse in a direction in which the deviation is reduced is output as a secondary command pulse (OUTP) to the drive control unit (2) to reduce the deviation.
[0027]
When the deviation returns sufficiently within (a) to (-b) within the predetermined deviation range (A) to (-B), the primary command pulse (PGP) is again used as the secondary command pulse (OUTP) as it is. ) As it is. The number of reverse high-speed pulses is counted as “dwell pulse” = primary command pulse (PGP) −secondary command pulse (OUTP).
[0028]
Conversely, on the left side of the deviation 0, when the secondary command pulse (OUTP) is slightly behind the rotor position pulse (ENCP) (= the deviation is small at the time of deceleration), the deviation is within the predetermined deviation range as described above. If so, the primary command pulse (PGP) is output as it is as the secondary command pulse (OUTP) to the drive control unit (2) until the deviation reaches a predetermined value on the acceleration side. When the deviation exceeds the predetermined deviation range, the step-out occurs.
[0029]
Therefore, the deviation exceeds the delay angle side deviation predetermined value (−B) (= the deviation is too small, and the rotor (1a) is the secondary command pulse in which the primary command pulse (PGP) is output as it is. Forward direction in which deviation is reduced by temporarily interrupting the primary command pulse (PGP) as it is output as the secondary command pulse (OUTP) to the drive control unit (2) The high-speed pulse is output as a secondary command pulse (OUTP) to the drive controller (2), and the deviation is reduced.
[0030]
If the deviation returns sufficiently inside (-b) from the delay angle side deviation predetermined value (-B), the primary command pulse (PGP) is output as it is as the secondary command pulse (OUTP) to the drive controller (2) as it is. . The above-described forward high-speed pulse is output in a direction in which the “accumulated pulse” is canceled when the “accumulated pulse” exists.
[0031]
As the set value of “delay angle side deviation” is set to “advance angle side”, the braking action becomes softer and the discharge of the “accumulated pulse” is completed earlier. On the other hand, if the deviation is set to the “delay angle side”, in other words, the brake action becomes stronger as the magnitude of the delay angle side deviation is reduced.
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described below with reference to the illustrated embodiments. FIG. 1 (b) is a conceptual diagram of the present invention. In a basic system composed of a command pulse generator (4), a drive control unit (2), and a stepping motor (1), the stepping motor (1) An encoder (3) that detects the rotor position of the stepping motor (1) [generally, a rotary encoder that is coaxial with a rotating shaft is used] is connected, and a command pulse generator (4) The pulse train interface unit (5) between the drive control unit (2) is provided with the pulse train control circuit (5a) according to the present invention, and the rotor position detection pulse (ENCP) output by the encoder (3) is A closed loop is formed by feeding back to the pulse train control circuit (5a).
[0033]
The pulse train interface unit (5) having the pulse train control circuit (5a) may be installed between the conventional command pulse generator (4) and the drive control unit (2) as an independent circuit, You may integrate in the command pulse generator (4) or a drive control part (2). The applied stepping motor (1) is not limited to a five-phase motor, but here, a five-phase motor will be described as a representative example.
[0034]
Command pulse generator (4) is trapezoidally driven with a forward primary command pulse (CWPGP) that rotates the stepping motor (1) in the forward direction or a reverse primary command output pulse (CCWPGP) that rotates in the reverse direction. The pulse output speed is slow at the beginning of startup, and gradually increases as the rotation of the stepping motor (1) accelerates.When the rotation speed becomes constant, the high-speed output is maintained, and during deceleration The output speed gradually decreases. If it is not necessary to specify the direction of the primary command pulse, it is simply (PGP).
[0035]
FIG. 2 is a block circuit diagram of the pulse train control circuit (5a) incorporated in the pulse train interface unit (5). The output direction discrimination unit (51), the output selection unit (52), the correction start discrimination unit (53), PG-OUT deviation counter (54), ENC period measurement circuit (55), OUT-ENC deviation counter (56), high-speed pulse generation circuit (57), correction pulse generation circuit (58), direction selector (59) and OUTP It consists of a periodic timer (60). The function of each part will be explained sequentially.
[0036]
The output selection unit (52) receives the primary command pulse (PGP) and receives it as the secondary command pulse (OUTP) or the input of the high-speed pulse generation circuit (57) to perform the deviation optimization process. It has a function of outputting a secondary command pulse (OUTP) or receiving a correction pulse generation circuit (58) and outputting a correction pulse for eliminating the “accumulated pulse” as a secondary command pulse (OUTP).
[0037]
The high-speed pulse generation circuit (57) has a function of generating a high-speed pulse and supplying the high-speed pulse for optimizing the excessively enlarged or reduced deviation to the output selection unit (52). Similarly, the correction pulse generation circuit (58) has a function of generating a correction pulse for eliminating the “accumulated pulse” and supplying the correction pulse to the output selection section (52).
[0038]
The output direction discriminating unit (51) receives the forward primary command pulse (CWPGP) or reverse primary command pulse (CCWPGP) from the command pulse generator (4), recognizes the direction, and selects the direction selection unit ( 59) The direction of the secondary command pulse (OUTP) output from 59 [that is, forward direction (= forward direction) or reverse direction (reverse direction)] is instructed to the direction selector (59) It has a function of instructing the direction selector (59) the direction of the secondary command pulse (OUTP) output based on the high-speed pulse for optimizing the enlarged or reduced deviation.
[0039]
The direction selection unit (59) receives the secondary command pulse (OUTP) from the output selection unit (52) and outputs the secondary command pulse (OUTP) according to the output direction instruction of the output direction discrimination unit (51). And PG-OUT deviation counter (54), OUT-ENC deviation counter (56), and OUTP cycle timer (60).
[0040]
The ENC cycle measuring circuit (55) has a function of receiving a rotor position pulse (ENCP) input and measuring a pulse generation cycle of the rotor position pulse (ENCP), and outputs a predetermined deviation range as an OUT-ENC deviation counter (56). Has the function of commanding.
[0041]
The OUT-ENC deviation counter (56) receives the rotor position pulse (ENCP) and the secondary command pulse (OUTP) input from the direction selector (59), and counts the deviation between the two (OUTP) (ENCP). When it is detected whether the deviation is within or beyond the predetermined deviation range based on the command from the ENC period measuring circuit (55), and the deviation exceeds the deviation predetermined range limit or the deviation predetermined range, The high-speed pulse flag is output to the output selection unit (52) to cancel the state where the deviation exceeds the predetermined range and to control the output selection unit (52) so that the deviation falls within the predetermined range.
[0042]
The OUTP cycle timer (60) measures the cycle of the secondary command pulse (OUTP) output from the constant direction selector (59).
[0043]
The PG-OUT deviation counter (54) has a function of receiving “primary command pulse (PGP)” and “secondary command pulse (OUTP)” and counting “accumulated pulses”.
[0044]
The correction start discriminating unit (53) receives the measurement result of the OUTP cycle timer (60), and outputs a correction pulse flag according to the number of “accumulated pulses” sent from the PG-OUT deviation counter (54). It has the function of outputting to (52). When the primary command pulse (PGP) is input to the correction start determination unit (53) while the correction pulse flag is being output, the correction pulse mode is immediately stopped and the deviation control mode is restored.
[0045]
The drive control unit (2) to which the secondary command pulse (OUTP) from the direction selection unit (59) is input includes a pulse width modulation circuit (21) that performs pulse width modulation control on the DC current supplied from the DC power supply voltage, The chopping control of the direct current by the pulse width modulation circuit (21), for example, a chopper (22) composed of a transistor or FET, a reactor (23) connected in series to the chopper (22), and a drive control unit (2) Connected between the (+) side and the ground side (GND) to drive the smoothing capacitor (C1) and stepping motor (1) to smooth the chopping controlled drive current in cooperation with the reactor (23) Power circuit (P) composed of output stage transistors (Tr1) (Tr2) to (Tr9) (Tr10) to be controlled, base of output stage transistors (Tr1) (Tr2) to (Tr9) (Tr10) according to the excitation sequence Counter / excitation sequence generator circuit to input switching signal to (24) And a pair of sense resistors (R1) and (R2) connected to the ground side (GND) and detecting a drive current.
[0046]
The counter / excitation sequence generation circuit (24) receives the secondary command pulse (OUTP) from the interface unit (5), and the counter (not shown) of the circuit (24) receives the secondary command pulse (OUTP). The excitation sequence is executed by counting pulses (OUTP).
[0047]
During operation of the stepping motor (1), a primary command pulse (CWPGP) or (CCWPGP) in the forward or reverse direction is output from the command pulse generator (4). Hereinafter, the case of normal rotation will be described as a representative example, and hereinafter simply referred to as (PGP).
[0048]
When the stepping motor (1) rises, the generation cycle of the primary command pulse (PGP) output from the command pulse generator (4) is slow and is accelerated as time elapses. After a certain period of time, the speed is constant, and when it is close to the stop position, it is decelerated and finally output so as to stop (see the broken line in FIG. 6).
[0049]
The primary command pulse (PGP) output from the command pulse generator (4) is output from the output direction discriminating unit (51) and the output select unit (52) of the pulse train control circuit (5a) of the interface unit (5) as described above. ) And the direction of the primary command pulse (PGP) input by the output direction determination unit (51) is determined, and the information is output to the direction selection unit (59). The direction is output from the output selection unit (52). The direction of the secondary command pulse (OUTP) output to the drive control unit (2) through the selection unit (59) is determined.
[0050]
The secondary command pulse (OUTP) from the output selection unit (52) is input to the direction selection unit (59) as described above, and is output from the direction selection unit (59) to the drive control unit (2). At the same time, it is branched and input to the PG-OUT deviation counter (54), OUT-ENC deviation counter (56) and OUTP cycle timer (60).
[0051]
The rotor position pulse (ENCP) from the encoder (3) is input to the OUT-ENC deviation counter (56), and the deviation between the secondary command pulse (OUTP) and the rotor position pulse (ENCP) is counted. is doing. The deviation is as described above. When the deviation is within the predetermined range, the OUT-ENC deviation counter (56) is a high-speed pulse flag (a signal output to the output selection section (52) when the deviation has expanded or reduced beyond the predetermined range). (The contents will be explained later.) Are not output, and the primary command pulse (PGP) is output as it is as the secondary command pulse (OUTP) to the direction selection unit (59), and in accordance with the instructions of the output direction discrimination unit (51) Is output. In this case, since it is normal rotation, a secondary command pulse (OUTP) in the normal rotation direction is output to the drive control section (2).
[0052]
Since the encoder (3) is directly connected to the rotor (1a) of the stepping motor (1), the rotation angle of the rotor (1a) is output as a rotor position pulse (ENCP) by the encoder (3) without time delay. . The rotor position pulse (ENCP) is input to the OUT-ENC deviation counter (56) as described above.
[0053]
The inertia load applied to the rotor (1a) of the stepping motor (1) is larger than the power of the stepping motor (1) as at the time of start-up, and the rotor (1a) follows the secondary command pulse (OUTP). If it becomes impossible, the delay appears as a delay of the rotor position pulse (ENCP) of the encoder (3). The difference between the two is counted by the OUT-ENC deviation counter (56), and when the deviation reaches a predetermined range limit or more, the OUT-ENC deviation counter (56) outputs the output selection unit (52). A high-speed pulse flag is output at (see the solid line in FIG. 6).
[0054]
The rotor position pulse (ENCP) is input to the ENC period measuring circuit (55), and the output period of the rotor position pulse (ENCP) is detected and a predetermined range of deviation is output to the OUT-ENC deviation counter (56). The comparison is performed within a predetermined deviation range.
[0055]
When the high-speed pulse flag is output from the OUT-ENC deviation counter (56) to the output selector (52), the high-speed pulse output from the high-speed pulse generation circuit (57) that has been interrupted is fetched at the same time as the command pulse. The primary command pulse (PGP) from the generator (4) passes through the output selection section (52) as it is and is output as the same secondary command pulse (OUTP) as the primary command pulse (PGP). The high-speed pulse is output as a secondary command pulse (OUTP) to the direction selection unit (59).
[0056]
The OUT-ENC deviation counter (56) instructs the output direction discriminating unit (51) to instruct the direction of the high-speed pulse output as the secondary command pulse (OUTP) output from the direction selection unit (59). Command pulse output direction command signal), and the high-speed pulse output as the secondary command pulse (OUTP) from the direction selector (59) is output according to the secondary command pulse output direction command signal. According to the output of the direction discriminating section (51), the deviation is outputted in the direction of reducing (reverse direction).
[0057]
If the deviation falls within the predetermined range as described above, the input of the high-speed pulse is cut off, and the primary command pulse (PGP) is again passed through the output selection unit (52) and direction selection unit (59) as it is as the secondary command pulse. (OUTP) is output to the drive control unit (2). As described above, acceleration is performed while maintaining a state where the deviation is within a predetermined range (see the solid line portion of the advance angle control portion in FIG. 6). FIGS. 7 (a) and 7 (b) show a state in which the rotor (1a) is smoothly accelerated while repeatedly outputting the high-speed pulses in the reverse direction so that the deviation is within a predetermined range. Therefore, the position of the pulse output is indicated by a stepped line.
[0058]
On the other hand, the secondary command pulse (OUTP) branched from the output selection unit (52) is input to the PG-OUT deviation counter (54) as described above, and is output as the secondary command pulse (OUTP). The number of high-speed pulses is counted and stored as “accumulated pulses”.
[0059]
When the rotor (1a) reaches a certain rotational speed, the rotor (1a) is maintained in that state and rotated at a constant speed. In this constant speed rotation, if the rotor (1a) vibrates for some reason and causes uneven rotation, the rotor (1a) is delayed (or advanced) with respect to the secondary command pulse (OUTP). In some cases, the deviation between (OUTP) and the rotor position pulse (ENCP) expands (or contracts) beyond a predetermined range limit or beyond. When enlarging, as described above, the primary command pulse (PGP) passes through the output select section (52) and stops being output as the secondary command pulse (OUTP), and the secondary command pulse (OUTP) A high-speed pulse is output as a reverse secondary command pulse (OUTP) from the direction selector (59) so as to match the position of the rotor (1a) that has delayed with respect to the secondary command pulse (OUTP) and the rotor position. The deviation from the pulse (ENCP) is controlled to be within a certain range.
[0060]
On the other hand, if the rotor (1a) moves too far and the deviation between the secondary command pulse (OUTP) and the rotor position pulse (ENCP) expands to the specified range limit or delay angle side, As described above, the primary command pulse (PGP) passes through the output selection section (52) and stops being output as the secondary command pulse (OUTP), and proceeds with respect to the secondary command pulse (OUTP). A high-speed pulse is output to the output selection unit (52) so as to match the position of the rotor (1a) that has passed, and this is output to the direction selection unit (59) as a secondary command pulse (OUTP), and the direction selection unit (59) The high-speed pulse is output as a secondary command pulse (OUTP) in the forward direction, and control is performed so that the deviation between the secondary command pulse (OUTP) and the rotor position pulse (ENCP) returns within a certain range.
[0061]
  At this time, the secondary command pulse (OUTP) in the forward direction is input to the PG-OUT deviation counter (54), and the above-mentioned “accumulated pulse = counting secondary command pulse (OUTP) in the reverse direction” exists. In this case, the difference is subtracted, and the difference is stored in the PG-OUT deviation counter (54). In this way, the “accumulated pulse” is discharged. Such deviation maintenance control is performed in constant speed drive.BecauseRotation unevenness of the rotor (1a) is suppressed and vibration is eliminated.
[0062]
Next, in the deceleration region, the rotational speed is gradually reduced while braking the rotor (1a). In this case, as described above, the rotor (1a) rotates too quickly with respect to the secondary command pulse (OUTP) due to inertial load, and the deviation between the rotor position pulse (ENCP) and the secondary command pulse (OUTP) May expand to the delay angle side. When such a state occurs, it causes a step-out.
[0063]
Therefore, as described above, when the deviation is expanded to the delay angle side by the OUT-ENC deviation counter (56) that constantly monitors the deviation between the rotor position pulse (ENCP) and the secondary command pulse (OUTP), Immediately as described above, the high-speed pulse flag is output to the output select section (52), and the output of the primary command pulse (PGP) as the secondary command pulse (OUTP) is cut off and the high-speed pulse of the high-speed pulse generation circuit (57) is turned off. Output to the direction selection unit (59), and output to the drive control unit (2) as a forward secondary command pulse (OUTP) to return the deviation to a predetermined deviation range (the solid line portion of the delay angle control portion in FIG. 6) reference).
[0064]
FIGS. 8A and 8B show a state where the rotor (1a) is smoothly decelerated while repeatedly outputting the forward high-speed pulse so that the deviation falls within a predetermined range. Therefore, the position of the pulse output is indicated by a stepped line.
[0065]
A secondary command pulse (OUTP) is branched and input from the constant direction selector (59) to the OUTP cycle timer (60), and the output cycle of the secondary command pulse (OUTP) is monitored. Therefore, when the “accumulated pulse” is present, it is possible to know at which point in time immediately before the stop position it is resolved. When the measurement result of the OUTP cycle timer (60) reaches the “pile pulse” cancellation time point, the correction start determination unit (53) sets the correction pulse flag as many as the number of “pump pulses” in order to eliminate “pump pulse”. ).
[0066]
When the correction pulse flag is output, the output selection unit (52) temporarily interrupts the primary command pulse (PGP) pulse output and takes in the correction pulse output from the correction pulse generation circuit (58). The number of correction pulses equal to the “pump pulse” is output as a secondary command pulse (OUTP) to the direction selection unit (59), and this is output according to the command of the output direction discrimination unit (51) (in this case, as the forward direction). Outputs to the drive control unit (2) and the “accumulated pulse” is eliminated. (Refer to Fig. 9 “Accumulated pulse correction”)
[0067]
(Example-1) An effect of preventing step-out during acceleration in the present invention will be described.
FIG. 10A shows a step-out in the rise when the present invention is not used. FIG. 10 (b) shows a case where the present invention is applied and rises smoothly without causing a step-out, and does not generate large rotation unevenness even during constant speed operation. Has stopped.
[0068]
(Example-2) An effect of preventing step-out during deceleration in the present invention will be described.
FIG. 11A shows the case where the present invention is not used and the step-out occurs during deceleration. FIG. 11B shows a case where the present invention is applied and the vehicle is smoothly decelerated without causing a step-out.
[0069]
(Example-3) The vibration suppression effect during constant speed operation in the present invention will be described.
FIG. 12 (a) shows the case where the present invention is not used and a large vibration is generated during constant speed driving. Further, a large vibration is generated from the deceleration to the stop. FIG. 12B shows the case where the present invention is applied, and vibration is effectively suppressed in constant speed operation and low speed operation just before stopping.
[0070]
(Example-4) An example of another vibration suppressing effect during constant speed operation in the present invention will be described.
FIG. 13 (a) shows a large vibration during constant speed driving when the present invention is not used. FIG. 13 (b) shows a case where the present invention is applied and vibration is effectively suppressed in constant speed operation.
[0071]
【The invention's effect】
The present invention detects a deviation between a rotor position pulse indicating a rotor position of a stepping motor and a secondary command pulse output to the drive control unit, and outputs a secondary command pulse to the drive control unit so that the deviation falls within a predetermined range. The output control of the stepping motor can be automatically adjusted during acceleration / constant speed operation / deceleration regardless of the rotor's inertia load. Smooth drive without any problem can be realized.
[0072]
Since the pulse train interface unit is provided between the command pulse generator and the drive control unit in this way, it can be installed independently of the command pulse generator and the drive control unit, and can also be applied to existing drive devices. There is an advantage that you can.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram of the present invention.
2 is a block circuit diagram of a pulse train control circuit of the interface unit of FIG.
FIG. 3 is an explanatory diagram of a predetermined deviation range in the present invention.
4 is an explanatory drawing of the lead angle side deviation in FIG. 3. FIG.
5 is an explanatory drawing of the delay angle side deviation in FIG. 3. FIG.
FIG. 6 is a comparative explanatory drawing of conventional trapezoidal drive and trapezoidal drive when the method of the present invention is adopted.
FIG. 7 is a graph showing the relationship between the position on the primary command pulse output of the pulse generator during acceleration of the present invention, the position on the secondary command pulse output, the position of the rotor, and the time of occurrence of the reverse high speed pulse
FIG. 8 is a graph showing the relationship between the position on the primary command pulse output of the pulse generator at the time of deceleration according to the present invention, the position on the secondary command pulse output, the rotor position, and the forward high-speed pulse generation time point.
FIG. 9 is an explanatory diagram for correcting accumulated pulses in the present invention in constant speed driving.
FIG. 10 is a comparison diagram of driving waveforms in the conventional example and Example 1 of the present invention.
FIG. 11 is a comparison diagram of driving waveforms in the conventional example and Example 2 of the present invention.
FIG. 12 is a comparison diagram of drive waveforms in the conventional example and Example 3 of the present invention.
FIG. 13 is a comparison diagram of drive waveforms in a conventional example and Example 4 of the present invention.
[Explanation of symbols]
(1) Stepping motor
(2) Drive controller
(3) Encoder
(4) Command pulse generator
(PGP) Primary command pulse
(OUTP) Secondary command pulse
(ENCP) Rotor position pulse

Claims (3)

A drive control unit that receives the rotor position pulse indicating the rotor position of the stepping motor and the primary command pulse output from the command pulse generator output to the drive control unit for driving the stepping motor, and controls the drive of the stepping motor. In a closed loop pulse train control method for a stepping motor that outputs a secondary command pulse and switches an excitation sequence of the stepping motor in synchronization with the secondary command pulse,
(A) The deviation between the secondary command pulse and the rotor position pulse is detected, and the advance angle side deviation predetermined value in which the secondary command pulse has advanced with respect to the rotor position pulse and the rotor position pulse A deviation predetermined range determined by a deviation predetermined value on the delay angle side in which the secondary command pulse is delayed, and a deviation between the secondary command pulse and the rotor position pulse is compared;
(B) When the deviation is smaller than the predetermined deviation range, the primary command pulse is output as it is as the secondary command pulse to the drive control unit,
(C) When the deviation proceeds to a state where the secondary command pulse has advanced with respect to the rotor position pulse and has expanded to a predetermined angle side deviation, the primary command pulse from the command pulse generator is held and this Is counted as a pool pulse, and a high-speed pulse in the direction opposite to the primary command pulse is output as a secondary command pulse to the drive control unit, whereby the deviation between the secondary command pulse and the rotor position pulse is reduced to a predetermined amount. Pull back the excitation sequence of the drive control unit temporarily until
(D) When the deviation has increased to a predetermined value on the delay angle side deviation in which the secondary command pulse is delayed with respect to the rotor position pulse, the primary command pulse from the command pulse generator is suspended. If there are any accumulated pulses, subtract them and store the difference, and output a high-speed pulse in the same direction as the primary command pulse to the drive control unit as a secondary command pulse. The excitation sequence of the drive controller is temporarily advanced until the deviation between the rotor position pulse and the rotor position pulse is reduced to a predetermined amount .
(E) The absolute value of the predetermined deviation value on the delay angle side when the secondary command pulse is delayed with respect to the rotor position pulse is the advance angle side when the secondary command pulse is advanced with respect to the rotor position pulse. By setting the deviation smaller than the absolute value of the predetermined deviation value, the deviation value on the lead angle side where the secondary command pulse has advanced with respect to the rotor position pulse and the secondary command pulse with respect to the rotor position pulse characterized thereby asymmetrically deviation predetermined range defined by the delay deviation predetermined value of delay angle side in the state with respect to the deviation 0, that you limit the vibration of the stepping motor rotor narrows the deviation predetermined range A closed loop pulse train control method for a stepping motor. (A) When the deviation between the rotor position pulse and the secondary command pulse reaches a limit value within a predetermined range due to a rapid change in the speed of the primary command pulse or due to uneven speed of the rotor position pulse that occurs when the rotor vibration occurs.
(B) A secondary command pulse that is sufficiently faster than the rotational speed of the rotor is output to the drive control unit in a predetermined amount in the direction in which the deviation is reduced, and the excitation sequence is temporarily drawn to the actual rotor position, causing deviation fluctuations. 2. The closed loop pulse train control method for a stepping motor according to claim 1, wherein torque ripple caused is reduced and vibration of the stepping motor is suppressed. A command pulse generator (4) for generating a primary command pulse (PGP) for driving the stepping motor (1), a drive control unit (2) for controlling the driving of the stepping motor (1), and a stepping motor (1 ) And is provided between the command pulse generator (4) and the drive control unit (2), which outputs the rotor position as a rotor position pulse (ENCP). ) And a pulse train interface unit (5) for receiving a secondary command pulse (OUTP) to the drive control unit (2) and taking in a primary command pulse (PGP) from the stepping motor. Because
The pulse train interface (5)
(A) A deviation between the secondary command pulse and the rotor position pulse is detected, and the rotor position pulse is detected. Deviation predetermined value determined by a predetermined deviation value on the advance angle side where the secondary command pulse is advanced and a predetermined deviation value on the delay angle side where the secondary command pulse is delayed with respect to the rotor position pulse. Compare the deviation between the range and secondary command pulse and rotor position pulse,
(B) When the deviation is smaller than the predetermined deviation range, the primary command pulse is output as it is as the secondary command pulse to the drive control unit,
(C) When the deviation proceeds to a state where the secondary command pulse has advanced with respect to the rotor position pulse and has expanded to a predetermined angle side deviation, the primary command pulse from the command pulse generator is held and this Is counted as a pool pulse, and a high-speed pulse in the direction opposite to the primary command pulse is output as a secondary command pulse to the drive control unit, whereby the deviation between the secondary command pulse and the rotor position pulse is reduced to a predetermined amount. Pull back the excitation sequence of the drive control unit temporarily until
(D) When the deviation has increased to a predetermined value on the delay angle side deviation in which the secondary command pulse is delayed with respect to the rotor position pulse, the primary command pulse from the command pulse generator is suspended. If there are any accumulated pulses, subtract them and store the difference, and output a high-speed pulse in the same direction as the primary command pulse to the drive control unit as a secondary command pulse. The excitation sequence of the drive controller is temporarily advanced until the deviation between the rotor position pulse and the rotor position pulse is reduced to a predetermined amount.
(E) The absolute value of the predetermined deviation value on the delay angle side when the secondary command pulse is delayed with respect to the rotor position pulse is the advance angle side when the secondary command pulse is advanced with respect to the rotor position pulse. By setting the deviation smaller than the absolute value of the predetermined deviation value, the deviation value on the lead angle side where the secondary command pulse has advanced with respect to the rotor position pulse and the secondary command pulse with respect to the rotor position pulse And a function for limiting the vibration of the rotor of the stepping motor by making the deviation predetermined range asymmetric with respect to the deviation 0 and narrowing the deviation predetermined range. A closed-loop pulse train control device for a stepping motor.

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