JPS61189199A - Drive controlling method of stepping motor - Google Patents

Abstract

PURPOSE:To prevent a stepout at switching time by outputting other exciting sequence data corresponding to the same counted value as a stored position of one exciting sequence data and then sequentially outputting the other sequence data. CONSTITUTION:Data from a CPU1 is transmitted to drivers PD1-PD4 to control stepping motors MY, MM, MC, MB. Four types of exciting states by 2-phase excitation system is presented in the memory of a CPU1 at every two steps of 1-2 phase excitation type, the exciting sequence data for applying the same exciting state by 1-2 phase exciting type is stored at the location corresponding to the stored location of one data of the exciting sequence data of 2-phase exciting type prepared by two. After the other exciting sequence data corresponding to the same counted value as the storing location of one exciting sequence data is output at switching time, the other exciting sequence data are sequentially output.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stepping motor drive control method.

[Conventional technology]

Stepping motors are easy to control digitally,
Due to the good responsiveness during operation and the ability to obtain a rotation speed proportional to the frequency of the input pulse signal,
In recent years, there has been a tendency for them to be used frequently, for example, as drive sources for peripheral devices in electronic computer systems.

An example of using a stepping motor is a plunger drive motor of an inkjet pump that pressurizes ink in a continuous injection type inkjet printer.

This inkjet pump rotates the plunger drive motor in the normal direction, converts the rotation into linear motion, and pushes the plunger into the pump chamber, thereby keeping the pressure inside the pump chamber constant at all times, and also by rotating the motor in the reverse direction. By retiring the plunger from the pump chamber, new ink is sucked into the pump chamber.

In continuous jet inkjet printers, when ejecting ink, it is necessary for the inkjet pump to eject ink with pressure fluctuations within 1%. It is necessary to make the inkjet pump smaller so that the inkjet pump can operate smoothly.

Therefore, for example, when ejecting ink when a three-phase or four-phase stepping motor is used, one phase and two phases are alternately excited. It is preferable to adopt a so-called 1-2 phase excitation force type and rotate the stepping motor at half the normal speed. On the other hand, when sucking ink, there is no need to particularly reduce the step angle, and the so-called two-phase
It is sufficient to adopt a phase excitation magnetic force type and rotate the stepping motor at a normal speed. In other words, during forward rotation and reverse rotation,
It is necessary to control the stepping motor by changing its excitation method.

Conventionally, in a stepping motor, the part that generates an excitation output signal according to the excitation method from input pulses uses a dedicated IC or the like. Drive control for reverse rotation, etc., was also performed by a method using so-called wired logic made up of these ICs (there is no specific literature).

[Problem that the invention seeks to solve]

However, in the case of the conventional configuration described above, a dedicated IC
Since they are expensive and additional circuits are required to drive them, there is a risk that the overall cost will be high.

In view of the above-mentioned circumstances, an object of the present invention is to enable cost-effective drive control of a stepping motor that is driven by appropriately switching the excitation method, and to enable smooth operation when switching. be.

[Means for solving problems]

A feature of the stepping motor drive control method according to the present invention is that the excitation sequence data for each input pulse using two different excitation methods is set so that the excitation sequence data of each input pulse does not exceed one step angle of the excitation method with a larger step angle. The excitation sequence data is combined and stored in separate storage means so as to correspond to the same counter value of the counter, and each excitation sequence data is sequentially output in a loop according to the counter value as the counter is added and subtracted. By doing this, the stepping motor is rotated forward and reverse, and when switching from one of these two excitation methods to the other, the storage location of one of the excitation sequence data that is being output at that time is the same. After outputting the other excitation sequence data corresponding to the counter value of , the other excitation sequence data is sequentially outputted.

[For production]

In other words, when controlling the drive of a stepping motor, the type of signal used to determine the order of excitation of each phase of the motor according to the excitation method is determined by the number of phases of the motor, its excitation method, etc. Moreover, it is limited. For example, when driving a 3-phase motor with a 2-phase excitation force type, there are 3 types, and when driving a 4-phase motor with a 1-2 phase excitation force type, there are only 8 types. Therefore, if these limited types of signals are stored in advance as sequence data and the sequence data is sequentially output in a loop according to the input pulse, the stepping motor will be driven according to the predetermined excitation sequence. It is. In addition, in order to accommodate a plurality of excitation methods, each sequence data may be stored in separate storage means, and the data for the required excitation method may be output.

However, for example, due to the technical requirements explained earlier, when driving with different wJ magnetic methods during forward and reverse rotation, the sequence data of the two excitation methods must be stored in a storage means in relation to each other. It is necessary to keep it. In other words, if the excitation method is switched at the same time as forward/reverse switching, two sequence data from different storage means will be output successively, but the phase excited by these two sequence data will be In a completely different way, the stepping motor at this time has 1 pulse per pulse.
This is because the rotation exceeds the step angle and the so-called step-out phenomenon is corrected.

Therefore, when storing two sequence data based on different excitation methods in separate storage means, data of each data that does not exceed one step angle of the excitation method with a large step angle is combined and stored in the same counter. In addition to corresponding to the counter value, when switching from one of the two excitation methods to the other, the other excitation sequence data corresponds to the same counter value as the storage position of one of the excitation sequence data output at that time. By sequentially outputting the other excitation sequence data after outputting , the step/knopping motor is prevented from rotating by more than one step angle per pulse when switching the excitation method.

〔Example〕

The present invention will be described in detail below based on the drawings.

FIG. 1 is a block diagram showing an example of a control device when a stepping motor to which the drive control method according to the present invention is applied is used as a plunger drive motor of an inkjet throat pump in a continuous jet inkjet printer.

The central processing unit (hereinafter referred to as CPU) (1) of the microcomputer includes a clock pulse generator (2).
) (CLK)
is entered via. From the output boat (Pfi), there are stepping motors (MY), (MM), ( MC), (Ml)
In addition, it is configured to output a pulse signal as a motor drive signal via separate data latch circuits (3a) to (3d) and power drive circuits (4a) to (4d). In addition, various control signals and drawing data from the outside are input to the CPU (1), and a pressure sensor (
psy), (ps,4), (psc), (
Detection signals from the ports (psm) are inputted via the input ports (1, , ), respectively.

And each of those sensors (psv), (PS)l)
, (psc).

Based on the detection result by (psi), each stepping motor □b), (MM), (MC), (M
1) is driven in the normal direction, and the rotation is converted into linear motion by a screw feed mechanism, so that the plunger is thrust into the pump chamber. Also, when the amount of ink remaining in the pump chamber becomes low after the specified drawing is completed, each motor (M
Y), (MM), (MC), and (MB) are driven in reverse, and the plunger is retired from the pump chamber.
It is configured to suck new ink into the pump chamber.

Each stepping motor (My), (MM), (M
c) The driving part (PD, ) for (1'Ls) is 4
The circuit diagram is shown in FIG. 2. In addition,
In the figure, the stepping motor is designated by (M), the data latch circuit is designated by (3), and the power drive circuit is designated by (4), each representing a plurality of components.

Eight data lines (Do) to (D,) from the CPU (1) are connected to the data latch circuit (3), and the data given by each of the data lines (Do) to (D,) is connected to the data latch circuit (3). Based on data, power drive circuit (4)
Through each phase (A) of the stepping motor (M),
(B), (TI) is configured to excite the stepping motor (TI).
This is a switching circuit consisting of a photosensor that switches between a driving state and a stopped state of M).

The stepping motor (M) used here is a 4-phase hybrid type, and the excitation method includes a 1-phase excitation force type that operates while sequentially exciting one phase, and a 1-phase excitation force type that operates while sequentially exciting one phase. Two-phase excitation force type that operates from the ground, and 1-2 that operates while alternately exciting one phase and two phases.
There are three types of phase excitation magnetic force type. In the inkjet pump of this embodiment, since it is necessary to eject ink with a pressure fluctuation within 1%, when ink is ejected by normal rotation of the motor (M) mentioned earlier, the stepping motor (M) is In order to reduce the step angle and operate smoothly, a 1-2 phase excitation force type is adopted in which the motor (M) rotates at half the normal speed. On the other hand, when ink is sucked by reversing the motor (M) as mentioned earlier, there is no need to particularly reduce the step angle, and the motor (M) runs at the normal speed.
A two-phase excitation force type in which M) rotates is adopted.

The excitation of each phase of the stepping motor (M) by the above-mentioned two excitation methods is based on the drive data transmitted from the CPU (1) via the data lines (Do) to (D,), as described earlier. The drive data will be described below.

First, FIG. 3(a) is a time chart showing the relationship between the input pulse and the excitation state of each phase in the two-phase excitation force formula. For each input pulse, two phases are always excited, and the excited phase changes sequentially, and the same excitation state is repeated every fifth input pulse, which is why there are four types of excitation states. It is. This stepping motor (M)
has 50 teeth formed around the rotor, and each pulse has a step angle of 1.86, that is, a step angle of 1.
The motor (M) will rotate at 8'. Now, if a state in which a certain phase is excited is "1" and a state in which it is not excited is "0", the state of each phase for each input pulse will be as shown in Table 1.

Furthermore, the A phase is connected to the data line (11°), the B phase is connected to the data line (nl), the W phase is connected to the data line (D2),
Then, by making the ■ phase correspond to the data line (D3), each phase (A), (B), (A)
, (B) can be expressed as 8-bit data from CP 'U (1). Table 2 shows the content of data for each input pulse and its hexadecimal code.

Table 2 Therefore, if expressed in hexadecimal code, it is "03 (111)".

“06 (Ill”, “,OC+o+”+”
The stepping motor (M) can be driven and rotated in the forward and reverse directions by sequentially outputting the four data of 09 (111") from the CPU (1) in a loop in that order or in the reverse order. The combination of these four data in that order will be referred to as two-phase excitation force type excitation sequence data.

Next, FIG. 3 (TI) is a time chart showing the relationship between the input pulse and the excitation state of each phase in the 1-2 phase excitation force formula. For each input pulse, one phase and two phases are excited alternately, and the excited phase changes sequentially, and the same excitation state is repeated every 9th input pulse, resulting in eight types of This is why there is an excitation state. According to this excitation method, the motor (M) rotates by 0.9° for each pulse, that is, at a step angle of 0.9°.

As before, if the excitation state of a certain phase is represented by a binary code of "0" and "1", the state of each phase for each input pulse will be as shown in Table 3 on the next page.

Furthermore, as before, each phase (A), (B),
(A) (If the excitation signal for the cup is expressed as 8-bit data from the CPU (1), it will be as shown in Table 4 on the next page.

Therefore, if expressed in hexadecimal code, it is 01 (H)”8”0
3(II>"+"02(Kl"+"06(H)
” + “04 (Ill” 1 “OCcM,” l
The stepping motor (M) can be rotated in the forward and reverse directions by sequentially outputting the eight data "08 (H)" l "09 (H)" from the CPU (1) in that order or in the reverse order in a loop. The combination of these eight pieces of data in that order will be referred to as the excitation sequence data of the 1-2 phase excitation method.

The sequence data of the two excitation methods mentioned above is CP
Within U (1), each separate memory (R1) is an example of the storage means shown in FIGS. 5 and 7, respectively.

(R2) are stored at consecutive addresses. An access counter is provided for reading out the sequence data, and as this counter is added or subtracted, the data stored at the address indicated by the counter value is output, thereby correcting the stepping motor (M). Configured to perform reversal. In addition, in this embodiment, as explained earlier, the motor (M) is configured to be driven using different excitation methods when the motor (M) is rotated in the forward or reverse direction.
As will be described later, in order to smoothly perform the excitation method switching operation, the same counter is used for the two sequence data.

In other words, in the 1-2 phase excitation method, there are 8 types of data, and in the 2-phase excitation method, there are 4 types of data.
By preparing two pieces of each data for the two-phase excitation method and storing the same data in adjacent addresses in the memory (R2), there are eight pieces of sequence data for the two-phase excitation method, and the same counter This allows access similar to the 1-2 phase excitation method. To read these data, when the motor rotates forward in the 1-2 phase excitation method, the counter is incremented once, and when the motor is reversed in the 2-phase excitation method, the counter is decremented twice. , so that necessary data can be output from the CPU (1).

Furthermore, as will be explained in detail later when explaining the operation, one step angle of the excitation method with the larger step angle among the excitation sequence data of the two excitation methods in each of the separate memories (Ill) and (R2). The combinations that do not exceed , are stored so that they correspond to the same count value of the counter.

In other words, the four types of excitation states by the two-phase excitation method are 1-2.
It appears every two steps in the phase excitation method, and one is placed in the position corresponding to the storage position of one of each excitation sequence data of the two-phase excitation method prepared in pairs.
- Stores excitation sequence data that provides the same excitation state using the two-phase excitation method. Table 5 on the next page shows excitation sequence data for both excitation methods in correspondence with counter values.

In other words, when switching from one of the two excitation methods to the other, the excitation sequence data of the other corresponding to the same counter value as the storage position of the excitation sequence data of one that is being output at that time is output. By sequentially outputting the other excitation sequence data later, it is possible to prevent the tax adjustment phenomenon from occurring.

For example, suppose that the motor (M) is driven by a 1-2 phase excitation force type during normal rotation, and the excitation method switching operation is performed when the output data is "06 n+)".

At this time, the output data “06 (I
The two-phase excitation force formula data stored in the position corresponding to the storage position of “ll” is also “06 (M)”.

Therefore, when driving the motor (M) in reverse using the two-phase excitation force type, first output the data of this two-phase excitation force type, then decrement the counter twice and sequentially output the excitation sequence data. , this prevents loss of synchronization.

Also, for example, the output data when switching the excitation method is “0”.
4 (approximately), the corresponding excitation sequence data of the two-phase excitation force formula is "06□," but the relationship between both data is smaller than the one step angle of the two-phase excitation force formula, and their Even if the signal is output continuously, no synchronization occurs.

In addition, in Table 5, the counter value is changed from “00 (H)” to “08 (H)”.
The reason why the number is set to 9 up to +Ill'' is as follows. That is, when the stepping motor (M) is reversed by the two-phase excitation force type, the counter is decremented twice, but the counter is decremented twice, but the counter is decremented twice. Decrementing “O
FF (111"), so if the counter value reaches 00 (ot) when decrementing, the counter is reset to "08 (II)". Therefore, the counter value "QQ (+n") is This is because dummy data is stored in the corresponding position, and the necessary data is stored corresponding to the position from the counter value "01 (lI,") to "0゜ゎ'. Also, When rotating the motor (M) in the forward direction using the 1-2 phase excitation force type, set the counter to 1.
It is incremented one by one, but the counter value is “08□,”
', reset the counter and write "0Ofll)"
This is how it works.

In addition to the format shown in Table 5, there is another possible storage format for the excitation sequence data of the side excitation method described earlier. That is, in the case shown in Table 5, for the excitation sequence data of the two-phase excitation force type prepared in pairs, the same excitation state by the 1-2 phase wJ magnetic method is placed at the position corresponding to the storage position of one of the excitation sequence data. In addition to storing the excitation sequence data that gives the
Excitation sequence data that provides an excitation state that is delayed by one step angle in the normal rotation direction based on the 1-2 phase excitation force formula with respect to the excitation state based on the data is stored. Instead of this method, the data is stored in the position corresponding to the storage position of the other excitation sequence data of the 2-phase excitation force type. This means that excitation sequence data that provides an excitation state advanced by a step angle may be stored. Table 6 shows the combination of both excitation sequence data in this format as a counter value.

Next, each separate memory (R1) is created as described above.

The forward/reverse operation of the stepping motor (M) using the excitation sequence data of the two excitation methods stored in the motor (R2) will be explained based on flowchart 1 of FIGS. 4 and 6. It is assumed that each data is stored in the format shown in Table 5 in the form of a table as shown in FIGS. 5 and 7.

FIG. 4 shows a flowchart during forward rotation using the -2-phase excitation method.

In this flow, first the data access counter (IC
Check the contents of the counter (ICNT) (No, 1). Only when the contents of this counter (ICNT) is "08181" in hexadecimal, reset the counter (ICNT) as mentioned earlier and write "00 (H)". Otherwise, do nothing and proceed to step (No, 3).

In step (No, 3), the memory (R1) stores the excitation sequence data based on the 1-2 phase excitation force formula.
The address of the start position (DAX (01)) of the X register (
IX). Next, read the contents of the counter (ICNT) into the BC register (IBC) (No, 4),
Add the contents of the BCC register (IBC) to the X register (IX) (No, 5).

Then, according to the contents of the X register (IX), the memory (
R1) to excitation sequence data (DATA(IX))
is loaded into the A register (IA) (No, 6), the contents of the A register (I^) are output to the data latch circuit (3) (No, 7), each sequence data is stored in the memory (R
8) as shown in FIG.

For example, if the counter (ICNT) is "03.)", "06 (ゎ')" will be output as the excitation sequence data.

When the output of excitation sequence data is completed, the counter (
After incrementing ICNT) once (No, 8),
Returning to step (No, 1'), the above-described flow is repeated. As a result, the excitation sequence data in the memory (R1) is sequentially output in a loop, and the stepping motor (M) is driven in the normal rotation direction.

FIG. 6 shows a flowchart at the time of reversal using the two-phase excitation force type.

In this flow, the start address (DAY (01)) of the memory (R2) where excitation sequence data based on the two-phase excitation force formula is stored is read into the Y register (IY) (No, 11), and then , reads the contents of the counter (ICNT) into the BC register (IBC) (No, 12),
Add it to Y register (IY) (No, 13)
, then, as in the case of the 1-2 phase excitation force formula, Y
According to the contents of the register (IY), load the excitation sequence data (DATA (IV)) from the memory (R2) into the A register (■8) (No, 14), and output it to the data launch circuit (3) (No. , 15), memory (R
The storage state of each sequence data in 2) is as shown in FIG.

When the output of excitation sequence data is completed, the counter (
After decrementing ICNT) once (No, 16),
Check the contents of the counter (TCNT) (No, 1)
7). If the counter (ICNT) is '00 (H)'', as mentioned earlier, after resetting the counter (TCNT) and setting it to '08 n++' (No, 18), (
No, return to step 11). Counter (ICNT)
If it is other than “00 () + 1”, it is decremented once more (No, 19), and then the counter (ICN
Check the contents of T) (No. 20). counter(
ICNT) is not “00 Tl11”, do nothing and return to step (No, 11), and count the counter (Tl11).
CNT) is “00..”, the counter (I
CNT) and set it to “08(II)” (N
o, 21), return to step (No, 11).

After returning to step (No, 11), the above-described flow is repeated. As a result, the excitation sequence data in the memory (R2) is sequentially output in a loop, and the stepping motor (M>) is driven in the reverse direction.

In the above-mentioned embodiment, the excitation method is a 2-phase excitation force type and a 1-2 phase excitation force type, and a case where both of these types are switched was explained. It is also possible to switch to the one-phase excitation force method, which is the excitation method used in the above, and this will be explained next.

First, the case of switching between the two-phase excitation force type and the one-phase excitation force type will be described.

The excitation sequence data based on the two-phase excitation force formula is as shown in Table 2. On the other hand, excitation sequence data based on the one-phase excitation force formula is as shown in Table 7 below.

Table 7 Comparing both data, there is no one that gives exactly the same excitation state, but for the data of "01 (□," by the one-phase excitation force formula, "03.H," by the two-phase excitation force formula) ”
Alternatively, the data of "09 (H)" may be combined. In other words, even if data from these re-excitation methods are output continuously when excitation methods are switched, the step angles resulting from them will not exceed one step angle for any of the excitation methods, and there is a risk of a step-out phenomenon occurring. There is no such thing.

Furthermore, in each re-excitation method, there are four types of excitation sequence data.

Therefore, it is not necessary to prepare two pieces of data for each excitation method so that the storage positions in the memory correspond to each other as in the case of the previous embodiment. Furthermore, when outputting data during forward and reverse rotation, the counters may be incremented or decremented once each.

Table 8 below and Table 9 on the next page show excitation sequence data based on the re-excitation method in two formats that correspond to counter values.

Table 8 Table 9 Next, the case of switching between the 1-2 phase excitation force type and the 1 phase excitation force type will be described.

The excitation sequence data using the 1-2 phase excitation force formula is shown in Table 4.
As shown in On the other hand, the excitation sequence data based on the one-phase excitation force formula is as shown in Table 7, as explained earlier. Therefore, similar to the case of switching between the 1-2 phase excitation force type and the 2 phase excitation force type described above,
It is necessary to prepare two pieces of excitation sequence data each using the one-phase excitation force formula.

Tables 1O and 11 below show excitation sequence data based on the re-excitation method in two formats that correspond to counter values.

Table 11 In addition, in the embodiment described above, the switching of the excitation method was performed at the same time as switching between forward and reverse directions.
In the drive control method according to the present invention, an excitation method is used during rotation in the same direction.In the embodiments described so far, a four-phase hybrid stepping motor (M) is used. A VR type or PM type may be used as the motor (M), and the number of phases is not limited.

Although not shown in a table, for motors (M) with 5 or more phases, there are 2-3 phase excitation methods and 3-4 phase excitation methods as excitation methods, and these different excitation methods can be used as appropriate. It is possible to perform drive control of the combined stepping motor (M).

The stepping motor (M) to which the present invention is applied is as follows:
In addition to the one for driving the plunger of the inkjet pump in the inkjet printer explained in the previous embodiment, the one for carriage feeding, belly button, dot feeding in various printers, etc., and the one for pen driving in XY plotter etc. There are also tape feeders for various uses such as tape leagues and tape punchers.

〔Effect of the invention〕

As described above, in the stepping motor drive control method according to the present invention, signals for determining the order of excitation of each phase of the motor according to the excitation method are stored in advance as sequence data, and input The stepping motor is driven by a predetermined excitation method by sequentially outputting the sequence data in a loop according to the pulse, so there is no need for an expensive dedicated IC for stepping motor drive control that was previously required. This can be omitted, and the circuit configuration for drive control can also be simplified, leading to cost reductions.

Moreover, when storing two sequence data based on different excitation methods in separate storage means, data of each data that does not exceed one step angle of the excitation method with a large step angle is combined and stored in the same counter. In addition to corresponding to the counter value, when switching from one of the two excitation methods to the other, the other excitation sequence data corresponds to the same counter value as the storage position of one of the excitation sequence data output at that time. By sequentially outputting the excitation sequence data of the other after outputting the excitation sequence data, the stepping motor does not rotate more than one step angle per pulse when switching the excitation method, so a tax adjustment phenomenon occurs. The motor can now operate smoothly when switching the excitation method without any risk.

Therefore, overall, it has become possible to provide an excellent control method that can perform highly accurate drive control of the stepping motor with a cost-effective configuration.

[Brief explanation of drawings]

The drawings show an embodiment of the stepping motor drive control method according to the present invention, in which FIG. 1 is a block diagram of a stepping motor control device, FIG. 2 is a circuit diagram of a stepping motor drive section, and FIG. 3 (() , (n) is a time chart showing the input pulse and the excitation state of each phase in the two-phase excitation method and the 1-2 phase excitation method, respectively, FIG. 4 is a flowchart of normal rotation operation of the stamping motor, and FIG. 5 is a table of excitation sequence data based on the 1-2 phase excitation force formula, No. 6
The figure is a flowchart of the reversing operation of a stepping motor.
FIG. 7 is a table of excitation sequence data based on the two-phase excitation force formula. (M)...Stepping motor, (R+), (
Rz)...Memorization means.

Claims (1)

[Claims] The excitation sequence data for each input pulse from two different excitation methods is combined with data that does not exceed one step angle of the excitation method with a large step angle to correspond to the same counter value of the counter. By storing each excitation sequence data in separate storage means and sequentially outputting each excitation sequence data in a loop according to the counter value as the counter is added and subtracted, the stepping motor can be rotated in the forward and reverse directions. At the same time, when switching from one of these two excitation methods to the other, the other excitation sequence data corresponding to the same counter value as the storage position of one of the excitation sequence data output at that time is output. A stepping motor drive control method that sequentially outputs the excitation sequence data of the other after