JPS6019240B2 - Stepping motor drive circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stepping motor drive circuit that rotates a stepping motor in forward and reverse directions without causing disturbances or the like.

The excitation method for driving a stepping motor is as follows:
Various methods are known, such as 1-phase-2-phase, 2-phase-2-phase, 2-phase-3-phase, etc., but since they involve step motion, they inherently include factors that cause vibration. be.

Therefore, resonance with the load may occur or abnormal phenomena such as disturbance may occur. Furthermore, at startup when the drive pulse frequency is high, the rotation of the rotor is delayed and cannot be followed, which may deviate from the stable operating range. This depends on the load torque, moment of inertia of the load, etc., and the limit of this frequency is called the self-starting and stopping frequency. or,
Stepping motors are often driven in forward and reverse directions, and there is almost no problem with reverse drive during low-speed rotation, but when the pulse frequency is high and reverse drive is during high-speed rotation, it is more difficult than when starting up as described above. As the rotation delay of the rotor increases, a state of disturbance occurs.

Therefore, the reversible frequency is generally a value close to 1/2 of the self-starting/sustaining frequency, but it is actually difficult to determine its limit due to various factors. FIG. 1 is a block diagram of the main parts of a conventional stepping motor drive circuit, and A
~ 4-phase stepping motor 1 with D-phase winding to 2-phase ~
This is for the case of driving using a two-phase excitation method. Each phase winding is excited by drive amplifiers 2A to 2D, and CMN indicates a common terminal, which is grounded, for example. The pulse distribution circuit 3 sequentially distributes the pulses a from the pulse generator 4 based on the forward/reverse rotation signal b from the forward/reverse command circuit 5. For example, when the forward/reverse signal b indicates forward rotation, the pulse a from the drive amplifier Pulse distribution is performed in the order of 2A to 2D, and the windings of the stepping motor 1 are divided into phases A, B, and
2 phases-2 in the combination of B, C phase, C, D phase, D, A phase
Phase excitation is performed. Further, when the forward/reverse signal b indicates reverse rotation, the magnets are excited in the opposite order to that described above. Forward/reverse signal b
However, there are two types: a synchronous type in which the output is synchronous with the pulse generator 4, and an asynchronous type in which the output is asynchronously.The operation of the latter asynchronous type will be briefly explained with reference to FIG.

A in the figure is a pulse a with a period T from the pulse generator 4, b' in the figure is a forward/reverse signal b from the forward/reverse command circuit 5, and "0"
” indicates forward rotation and “1” indicates reverse rotation, drive amplifier 2A~
The 2D output will be as shown in Fig. 2c-f. Time tl
When the forward/reverse signal b is reversed from "0" to "1", the A-phase winding is being energized and the B-phase winding is at the beginning of excitation, as shown in Figure 2d. By being excited only for a time of Or it may cause disturbance.

FIG. 3 is an explanatory diagram of the operation of the synchronous type, where a indicates a pulse a with a period T from the pulse generator 4, b indicates a forward/reverse signal b, and c indicates the output of the drive amplifiers 2A to 20, and at time t2, The forward/reverse signal b is inverted from "0" to "1" and the B-phase winding is excited for a time T, resulting in improved stability compared to the asynchronous type.

However, when the self-start/stop frequency is set to 1'2T, the excitation time of T during the above-mentioned switching from forward rotation to reverse rotation is not sufficient, and there is a possibility that step-out or disturbance occurs. The present invention has been made to improve the conventional drawbacks as described above, and its purpose is to stably perform forward and reverse driving with a simple configuration.

Examples will be described in detail below. FIG. 4 is a block diagram of an embodiment of the present invention, in which the same symbols as in FIG. 1 indicate the same parts, and 6 is an inversion processing circuit.

This inversion processing circuit 6 is configured so that the forward/reverse signal b changes from “0” to “1”.
” or “1” to “0” to reverse the rotation direction of the stepping motor 1, the pulses from the pulse generator 4 are fixed at the “1” or “0” level for a certain period of time, and the stepping motor 1 is stopped for a certain period of time.FIG. 5 is a block diagram of one embodiment of the inversion processing circuit 6.

The pulse a is applied to the clock terminal C of the flip-flop FFI and the AND circuit AND, the voltage yc is applied to the data terminal D of the flip-flop FFI, and the output of the exclusive OR circuit EXOR is applied to the reset terminal R.
Therefore, when "1" is added to the reset terminal R, the output terminal Q becomes "0", and the AND circuit AN
D is closed. Also, pulse a of the output of the AND circuit AND
' is added to the pulse distribution circuit 3. The forward/reverse signal b is “
It is directly applied from the inversion processing circuit 6 to the pulse distribution circuit 3 as a forward/reverse signal b', and is also applied via the buffer circuit BF to an integrating circuit consisting of a resistor R3 and a capacitor CI, and to an exclusive OR circuit EXOR, respectively. Added.

The output of the integrating circuit is added to the comparator circuit COMP, and the voltage V
It is compared with the value obtained by dividing c by resistors R1 and R2. FIG. 6 is an explanatory diagram of the operation, and the figure a shows the synchronized T pulse a from the pulse generator 4, and b shows the forward/reverse signal b. At time t3, the forward/reverse signal b changes from "0" to "1". At that time, since the output of OMP to the comparator circuit is "0", the output of exclusive OR circuit EXOR becomes "1", and flip-flop FFI is reset. and buffer circuit BF
The output of the comparator circuit COM is integrated, and after a time corresponding to the time constant of CI and R3, when the integrated output increases beyond the voltage divided by the resistors R1 and R2, the output of the comparator circuit COM becomes "
1", and the output of the exclusive OR circuit EXOR becomes "0". Therefore, the output of the exclusive OR circuit EXOR becomes "1" at time 71 in FIG.
The output terminal Q of the output terminal Q is set by the pulse a after time 71 as shown in FIG. A pulse a' shown in FIG. 6e will be applied. Also, when the forward/reverse signal b changes from "1" to "0" at time t4,
The output of the exclusive OR circuit EXOR becomes "1" and becomes "0" after a time interval of 2, which is associated with the discharging time constant of the integrating circuit.

Hence Flipf. Is it time after the output terminal Q of the FFI becomes “0”? It is set by pulse a of 2 and becomes “1”.
"A pulse a' with one pulse a inhibited next to it is applied to the pulse distribution circuit 3. The pulse a shown in FIG.
' is applied to the pulse distribution circuit 3, the outputs of the drive amplifiers 2A to 2D become as shown in FIG. Since the line is energized, no decoupling or disturbances occur.

The above embodiment deals with the case where one pulse is inhibited by setting the time constant of the integrating circuit during forward/reverse switching.
, 2 can also be set.

or? It can also be set to 1 = 2 or 2. Since the integration circuit and the comparison circuit COMP are for inhibiting the output of the pulse a for a predetermined period of time after the reversal of the forward/reverse signal b, a monostable multipipelator that is triggered by the reversal of the forward/reverse signal b is used. You can also do that. FIG. 7 shows a block diagram of another embodiment of the inversion processing circuit 6, in which the same symbols as in FIG. 5 indicate the same parts, OR is an OR circuit, and FF2 is a flip-flop.

The output of the comparison circuit COMP is used as the forward/reverse signal b' to be applied to the pulse distribution circuit 3, the output of the exclusive OR circuit EXOR is applied to the data terminal D of the flip-flop FF2, and the output of the output terminal Q of the flip-flop FF2 is applied to the OR circuit PR. Pulse a is applied to pulse distribution circuit 3 together with pulse a through
'. FIG. 8 is an explanatory diagram of the operation, where a shows the pulse a, b shows the forward/reverse signal b, the pulse a' output from the inversion processing circuit is shown in the figure f, and the forward/reverse signal b' is shown in the figure c. becomes.

Further, d in the same figure shows the output of the exclusive OR circuit EXOR, and e in the same figure shows the output of the output terminal Q of the flip-flop FF2. Therefore, the forward/reverse signal b' is delayed by 73 and 74, and the pulse is held at ``1'' between the two pulses.Also, g to j in the same figure are caused by the pulse a' and the forward/reverse signal b'. The pulse distribution circuit 3 operates and outputs are shown from the drive amplifiers 2A to 2D, and in this embodiment as well, excitation/weakness for at least some time is ensured during the inversion operation.As explained above, The present invention provides a synchronous type by providing an inversion processing circuit 6 that holds the pulse a of the synchronous T at "0" or "1" for at least one pulse and applies it to the pulse distribution circuit 3 when the forward/reverse signal b is inverted. Of course, even if it is an asynchronous type, the winding of the stepping motor 1 can continue to be excited for a period of nT (n = an integer of 2 or more) synchronized with pulse a, so stepping at the self-start/stop frequency is possible. Even if the rotation direction is reversed while the motor is being driven, it can be followed with good response, and no synchronization or disturbance will occur.

In addition, in the above-mentioned embodiment, the 4-phase stepping motor is replaced with 2-phase-2
This is for the case of excitation using the phase excitation method, but 5
The present invention can also be applied to stepping motors having polyphase windings such as 1-phase and 6-phase windings, and can also be applied to excitation systems such as 1-phase-2-phase and 2-phase-3-phase.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional stepping motor drive circuit, FIGS. 2 and 3 are operation explanatory diagrams of conventional asynchronous and synchronous types, and FIG. 4 is a block diagram of an embodiment of the present invention. FIGS. 5 and 7 are block diagrams of different embodiments of the inversion processing circuit, and FIGS. 6 and 8 are operation explanatory diagrams of FIGS. 5 and 7, respectively. 1 is a stepping motor, 2A to 2D are drive amplifiers, 3
4 is a pulse distribution circuit, 4 is a pulse generator, 5 is a forward/reverse command circuit, and 6 is an inversion belief circuit. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. Each phase winding of a stepping motor having multiple phase windings is equipped with a pulse distribution circuit to which pulses of a predetermined period are applied and the pulses are distributed sequentially according to a forward/reverse signal, and according to the output of the pulse distribution circuit, each phase winding is In a stepping motor drive circuit that excites a line and drives the stepping motor in the rotational direction specified by the forward/reverse signal, the stepper motor is configured to generate at least one pulse of the predetermined period when the forward/reverse signal is reversed.
A stepping motor drive circuit comprising an inversion processing circuit that forcibly holds a pulse at "0" or "1" and adds it to the pulse distribution circuit.