JPH01274690A - Driving method for linear pulse motor - Google Patents

Abstract

PURPOSE:To avoid the influence of hysteresis characteristic on the deflection of a mover, by inverting the mover after the mover is deflected in the forward direction by as many command pulses as required by an amplitude, and by adding as many incremental component pulses as required by the amplitude at the time of the inversion, to the command pulse. CONSTITUTION:First, N command pulses according to an amplitude is applied, and a mover is deflected in the forward direction. After that, (2N+alpha1) pulses are applied, and the mover is deflected in the reverse direction. Besides, (N+alpha2) pulses are applied, and the mover is deflected in the forward direction, and the mover is returned to the point of deflection zero. In this case, the quantities alpha1 and alpha2 of incremental component pulses are set in a quantity according to the amplitude, and the generation time t is made sufficiently shorter than command pulse generation times(t), 2t. As a result, influence by hysteresis characteristic can be cancelled.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for driving a linear pulse motor, and in particular, the movable element of the linear pulse motor is driven by a command pulse so that it follows an object that moves with a certain amplitude. The present invention relates to a driving method in which control is performed.

(Prior Art) The field of application of pulse motors as servo motors or actuators in automation mechanisms has recently expanded rapidly, and it is thought that the range of applications will continue to expand in the future.

When a linear pulse motor is used as a servo motor or actuator, and the moving element is controlled to follow an object moving with a certain amplitude, hysteresis characteristics become a problem regarding the movement of the moving element.For example, the development of computers Along with this, various improvements have been made to floppy disk drives, which also use linear pulse motors to drive magnetic heads. In high-density floppy disk drives, the recording medium may undergo eccentric movement due to expansion and contraction due to heat, chucking errors, etc., and the linear pulse motor for driving the magnetic head perfectly follows this eccentric movement and compensates for the eccentricity. In this case, even if the linear pulse motor is reciprocated with minute feed by microstep drive, there will be a delay in the movement of the linear pulse motor relative to the command input pulse due to hysteresis due to residual magnetism. The relationship between the command pulse and the displacement of the moving element of the linear pulse motor when microstep driving the linear pulse motor will be explained based on FIG.

Figure 4 (a) shows the input state of command pulses with time t on the horizontal axis, and Figure 4 (b) shows the number of command pulses on the horizontal axis and the displacement of the slider on the vertical axis. The relationship with child deviation is shown. As shown in Figure 4 (a), N pulses are applied to command the mover at the point of zero deviation to move in the forward direction, causing it to deflect in the forward direction, and then commanding it to move in the reverse direction. If you give 2N pulses to deflect in the opposite direction, then give N pulses that command forward movement to return the mover, the mover will theoretically move to the point of zero deviation. It should be. However, the mover does not actually return to the point of zero deviation.To explain this in more detail in Figure 4(b), the mover that is currently at the point of zero deviation is instructed to move in the forward direction. When N pulses are given to cause the mover to deviate in the forward direction to point does not return to the point of zero deviation, and is insufficient to return by xI (ILs).If it is attempted to return this to the point of zero deviation, α out of the remaining eight reverse direction movement command pulses are required. Therefore, the deflection point of the mover due to 2N backward movement command pulses does not reach -x1 and -x2 (x〾〉x
2), and from that point -x2, the mover is moved in the positive direction by the next N positive direction movement command pulses, but with these N pulses, the mover does not move to the point of zero deflection. ,

FIG. 5 is a diagram showing the relationship between the displacement of the moving element and time.

In FIG. 5, graph (a) represents the relationship between the theoretical displacement of the moving element due to the command pulse and time, and graph (b)
) represents the relationship between the actual displacement of the moving element and time. That is, N pulses that command forward movement are applied to deviate the mover in the forward direction, and then 2N pulses that command reverse direction movement are applied to deviate the mover in the opposite direction. , and then further apply N pulses that command forward movement to cause the mover to deviate in the positive direction. N
It switches from the forward direction to the reverse direction at time 2t (the time point at which the Nth generation of the first half of 2N reverse direction command pulses occurs), and passes through the zero deviation point at time 3t (the time point at which the The direction is switched from the reverse direction to the forward direction at the second half of the Nth generation of the direction command pulse 2N side), and the deviation is zero at time 4t (the time of the Nth generation of the next positive direction command pulse). should be reached. However, in reality, in response to the N@ pulse that commands the first forward movement, the mover deviates to xI at time t, changes the movement direction at that point, and then receives 2N pulses that command the next reverse direction movement. 2t+
t+, and the deflection point that the mover reaches with the 2Nth pulse is -X2 (XI > direction, but does not reach the point of zero deviation at time 4t, and is further moved by the next N positive direction movement command pulses to reach the point of zero deviation at time 4t+t2. In this way, the movement of the moving element has a hysteresis characteristic with respect to its deflection, which causes a delay in the following movement of the moving element, making control difficult.

(Problem to be Solved by the Invention) Therefore, the problem to be solved by the present invention is that when the moving element of a linear pulse motor is driven by a command pulse and is controlled to follow an object that moves with a certain amplitude,
It is an object of the present invention to provide a driving method that prevents delay in the following movement of a moving element.

(Means for Solving the Problems) The present invention provides a method for driving a moving element of a linear pulse motor using a command pulse, and when controlling the moving element to follow an object moving with a certain amplitude, the moving element lags behind the following movement of the moving element. In order to prevent this from occurring, it is based on the idea that it is sufficient to eliminate the effect of the hysteresis characteristic regarding the displacement of the mover during microstep drive, and hysteresis can be canceled by appropriately applying input pulses. That is.

When the moving element of a linear pulse motor is driven by command pulses and controlled to follow an object moving with a certain amplitude, the reason for the delay in the following movement of the moving element is due to its hysteresis characteristic. After being deflected in the positive direction by N command pulses, when it is deflected in the reverse direction, the N command pulses do not return to the original zero deflection point, and the next reverse direction command pulse This is due to the generation time of the supplementary pulses, since some of them are required supplementally. Therefore, according to the present invention, after the mover is deflected in the positive direction by a number of command pulses corresponding to the above-mentioned amplitude, during one reversal, the number of incremental pulses corresponding to the above-mentioned amplitude is generated within a minute time, and the number of incremental pulses corresponding to the above-mentioned amplitude is generated within a minute time. An incremental pulse is added to the command pulse to drive the linear pulse motor to deflect the slider in the opposite direction. Thereby, the influence of the hysteresis characteristic on the displacement of the moving element is removed, and the above-mentioned object of not causing a delay in the following movement of the moving element is achieved.

Preferably, according to one aspect of the present invention, the relationship between the amplitude, the number of command pulses, and the number of incremental pulses is written in advance in a storage means of the linear pulse motor drive device for various cases, and the amplitude is detected; The configuration is such that the number of command pulses and the number of incremental pulses corresponding to the detected amplitude can be automatically determined.

(Function) According to the present invention, after the mover is deflected in the positive direction by a number of command pulses corresponding to the amplitude to be followed, at the time of reversal, the number of incremental pulses corresponding to the amplitude is generated within a minute time. However, since the command pulse is added to the command pulse and applied to deflect the movable element in the opposite direction, the movable element can perform the following movement without delay.

(Embodiment) As described above, in the case where the moving element of a linear pulse motor is driven by a command pulse and is controlled to follow an object moving with a certain amplitude, the present invention provides a method that lags behind the following movement of the linear pulse motor. In order to prevent this from occurring, it is based on the idea that it is sufficient to eliminate the influence of hysteresis characteristics regarding the displacement of the mover during microstep driving.

Therefore, according to the present invention, when moving the moving element of a linear pulse motor to follow an object moving with a certain amplitude, the moving element is first moved from the point of zero deviation to the point of the maximum value of the amplitude in the positive direction. As shown in Figure 1, as shown in Figure 1, when moving the deflection to the point where the amplitude is maximum in the reverse direction, and then returning to the point where the deflection is zero, first Give N command pulses necessary for movement to deflect the mover in the forward direction, then give 2N+α1 pulses to command reverse direction movement to deflect the mover in the reverse direction, and then Also, by giving N+02 pulses that command forward movement and deflecting the mover in the positive direction, the mover returns to the point of zero deflection.The amount of hysteresis when no increasing pulses are added is as follows: As shown in FIGS. 2(a) and 2(b), since they change depending on the moving amplitude of the moving element, that is, the number of command pulses, the numbers α1 and α2 of increasing pulses are changed according to the moving amplitude of the moving element.

Further, the generation time of the α1 and α2 incremental pulses must be sufficiently shorter than the generation time of the basic command pulse. In other words, the generation time of α1 pulses is set to be a sufficiently small time compared to the generation time of 2N pulses so that the generation time of 2N+α1 pulses is not substantially different from the generation time of 2N pulses, and N+02 pulses are generated. For example, in a linear pulse motor, the generation time of α2 pulses is set to a sufficiently small time compared to the generation time of N pulses so that the generation time of the pulses is not substantially different from the generation time of N pulses. When used to drive a magnetic head in a high-density floppy disk device, the generation time of the incremental pulse is set to about several 107 L seconds in the following movement for correcting the eccentricity of the moving element of the linear pulse motor.

In this case, the period of eccentric movement of the deployment medium is 100 m5ec
On the other hand, the generation time of the incremental pulse is several 1
07L see, the generation time of the incremental pulse with respect to the generation time of the command pulse is a value that should be ignored, and there is virtually no delay in the follow-up movement of the mover due to the generation of the incremental pulse. In the figure, if the time for giving N basic command pulses is t, and the time for generating an incremental pulse is Δt, if Δtct can be set, Δt
0, there is virtually no delay between the time when the basic command pulse is applied and the time when the basic command pulse plus the incremental pulse is applied, and therefore, the deflection of the mover by N basic pulses is It can be assumed that there is no substantial delay between the position time and the displacement time of the mover due to the addition of the incremental pulse to the fundamental pulse. That is, the movement of the mover is
This is because the pulse generation time can be considered to be delayed in this manner. To this end, the incremental pulses are generated at a higher frequency than the basic command pulses, and their generation time is minimized.

FIG. 3 is a diagram for explaining the process for carrying out the linear pulse motor driving method according to the present invention, in which the symbol lO is the amount of amplitude (for example, a high-density floppy disk 11 is a means for detecting the off-track amount (when used for eccentricity correction of a recording medium in the apparatus), and 11 determines the number of command pulses and the number of incremental pulses corresponding to this detected amount, and for example, as described above, N pulses in the forward direction, 2N+α1 pulses in the reverse direction, and N+02 pulses in the forward direction are sequentially generated and transferred to the microstep drive circuit.

Pulse number determination Φ generation means, which determines the amplitude to be followed;
The relationship between the number of command pulses and the number of incremental pulses is written in advance in the storage means of the linear pulse motor driving means for various cases, and the number of command pulses and the number of incremental pulses corresponding to the detected amplitude are automatically determined. It is determined. The number of pulses transferred to the microstep drive circuit is counted by the counter 12, and a digital signal representing the current value corresponding to the counted value is sent to the ROM 13 and RO.
N 13', each converted into an analog signal by a digital/analog converter 14.14°, and amplified by an amplifier 15.15°. It is supplied to the coil 18'. In other words, the microstep drive circuit is A
The third A is connected to the phase coil 18 and the B-phase coil 18', respectively.
This is a circuit that flows currents 1 sin θ and raogo as shown in the figure. When the count value of the counter 12 is zero, the current at the 0 point in FIG. The current applied to the A-phase coil 18 and the B-phase coil 16° changes in the positive direction as shown in the figure. changes in the negative direction, and continuous driving is performed. For this reason, ROM 13 and ROM 13° store data that changes with a sine function and a cosine function, respectively.

(Effects of the Invention) According to the present invention, as described above, the moving element of the linear pulse motor is driven by the command pulse.

When controlling an object to follow a moving object with a certain amplitude, by additionally applying an incremental pulse that occurs at a minute time when the pulse is reversed, the influence of hysteresis characteristics can be canceled out, and the movement of the moving object can be controlled to follow. It has the effect of not causing delays in exercise.

In addition, the relationship between the amplitude to be followed, the number of command pulses, and the number of incremental pulses is written in advance in the storage means of the linear pulse motor drive device for various cases, and the above amplitude is detected and the relationship between the number of command pulses and the number of incremental pulses is written in advance. If the configuration is such that the number of command pulses and the number of incremental pulses to be used can be automatically determined, a remarkable effect can be obtained in that the mover can completely follow any amplitude without delay. Demonstrate.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the additional generation of incremental pulses in the linear pulse motor driving method according to the present invention, and FIG. 2 is a diagram for explaining the relationship between the incremental pulses and hysteresis characteristics. ) is a diagram showing the relationship between the number of pulses and deviation, (b) is a diagram showing the relationship between the amplitude, that is, the number of command pulses, and the amount of hysteresis, and FIG. 3 is a diagram showing the configuration for implementing the linear pulse motor driving method according to the present invention. FIG. 3A is a diagram showing the current flowing through the A-phase winding and B-phase winding of the linear pulse motor, and FIG. 4 is a diagram for explaining the drawbacks of the conventional linear pulse motor driving method. ,
(k) is a diagram showing the relationship between command pulse application and time, (b
) is a diagram showing hysteresis characteristics, and FIG. 5 is a diagram for explaining the time delay in the following movement of the moving element in the conventional linear pulse motor driving method. 10,. 9. Tracking amplitude detection means. 11. Pulse number determination/generation means; 12. Counter. 13.13',,,,ROM, 14.14°001. Digital/analog strange! ! ! ! !
Base, 15.15"010.Amplifier. 1B.00.A phase coil, 1B',...B phase coil.

Claims (1)

[Claims] 1. In the case where a moving element of a linear pulse motor is driven by command pulses and controlled to follow an object moving with a certain amplitude, the moving element is driven by a number of command pulses corresponding to the amplitude. After deflecting in the positive direction, at the time of reversal, a number of incremental pulses corresponding to the amplitude is generated within a minute time, and the incremental pulses are added to the command pulse to deflect the mover in the reverse direction, A method for driving a linear pulse motor, characterized in that the influence of hysteresis characteristics on the displacement of the moving element is thereby removed, and no delay is caused in the following movement of the moving element. 2. The relationship between the above amplitude, the number of command pulses, and the number of incremental pulses is written in advance in the storage means of the linear pulse motor drive device for various cases, the above amplitude is detected, and a command corresponding to the detected amplitude is written. 2. The method for driving a linear pulse motor according to claim 1, wherein the number of pulses and the number of incremental pulses are automatically determined. 3. When a linear pulse motor is used to drive a magnetic head in a high-density floppy disk device and the mover of the linear pulse motor is made to follow the eccentric movement of a recording medium to perform eccentricity correction, After the slider is deflected in the positive direction by a number of command pulses corresponding to the amplitude, at the time of reversal, the number of incremental pulses corresponding to the above amplitude is generated within a minute time, added to the above command pulse, and applied. A method for driving a linear pulse motor, characterized in that the influence of hysteresis characteristics on the displacement of the moving element is thereby removed, and no delay is caused in the following movement of the moving element. 4. The method for driving a linear pulse motor according to claim 3, wherein the incremental pulse is generated within a short period of about several tens of microseconds.