JP2753373B2 - Positioning control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a high-speed positioning control method in a positioning control device and a circuit configuration for realizing the control method.

[Conventional technology]

Conventionally, positioning control includes
l As described on pages 28 to 34 of 24, No. 4 (April 1988), a controlled object including unknown disturbances and uncertain non-linear parameters is set, and the output can be used as the output of the reference model. It has been argued that the dual robust model tracking control in which the tracking is performed with an accuracy of 1 is effective.

[Problems to be solved by the invention]

In order to realize high-speed positioning control, it is not clear what to select as a reference model and what kind of circuit configuration should be adopted in the above-mentioned conventional technology, and it is applied to actual positioning control. There was a problem.

An object of the present invention is to provide a high-speed positioning control method suitable for a positioning control device, and further to provide an optimal circuit configuration when the control method is applied to a positioning control device. .

[Means for solving the problem]

In order to achieve the above object, in a positioning control device according to the present invention, a positive control is applied to a positioning control method of a control target as a reference model of a dual robust model following control.

In the above control, in order to reduce the overall program capacity of the arithmetic processing device, the operation of the behavior of the reference model is performed for each sample period.

In order to shorten the sample period in the above control, the calculation of the behavior of the reference model is calculated in advance for each sample period in accordance with the moving distance and is stored in a table.

Further, as a positioning control circuit configuration for realizing the control, a positioning signal generation circuit, an arithmetic processing unit, a D / A converter, and a positioning control mechanism are provided.

Further, in the positioning control circuit configuration, a position number generation circuit is provided in order to reduce a processing load on an arithmetic processing unit.

Further, in the positioning control circuit configuration, an A / D converter is provided for taking in the position signal output from the position signal generation circuit into the arithmetic processing unit.

Further, in the positioning control circuit configuration, a sample period stabilizing circuit is provided in order to stabilize the sample period.

In the positioning control circuit configuration, in order to achieve a reduction in circuit area, the A / D converter, the D / A converter, the arithmetic processing unit, the RAM, and the ROM are integrated into one package IC.

Furthermore, in order to achieve a reduction in the processing load on the arithmetic processing unit and a reduction in circuit area, the IC is a one-package IC including a position number generation circuit.

[Action]

In the positioning control device of the present invention, the use of the positive cast control as the reference model of the dual robust model follow-up control means that the object to be controlled moves between the current position and the target position in a single vibration from the function of the positive cast control. Will do. When the control target arrives at the target position, ideally, the speed of the control target is 0. Therefore, if the control rule is switched to a control rule that can control the positioning of the control target in a stable manner at this moment, the control target can be controlled. Since the position is 0 and the speed is 0, the control ends. By the positive cast control, the positioning of the control target becomes extremely fast. However, when identifying the actual controlled object,
Due to the parameter error and unknown disturbance of the controlled object, the behavior difference between the reference model and the controlled object appears, and the position of the controlled object does not reach the target position at the switching point of the control law.
The speed may not be 0. For this reason, convergence time after switching may be required, or positioning of the control target may even fail. Therefore, as shown in FIG. 1, a reference model in which positive control is performed on the numerical model of the controlled object is considered, and a feedback coefficient is added to the difference between the state variable of the position and speed of the reference model and the state variable of the controlled object. By adding the calculated value to the control input u (t) of the control target, the control target matches the behavior of the reference model. As described above, the matching method is the dual robust model following control,
By using the positive cast control as the reference model of this control, stable and high-speed positioning control of the control target can be realized.

Further, when the positive cast control is used as the reference model of the dual robust model following control, the behavior of the reference model is calculated for each sample period, so that the entire program capacity of the processing device can be suppressed.

Further, when using the positive cast control for the reference model of the dual robust model following control, the calculation of the behavior of the reference model is calculated in advance for each sample period in accordance with the moving distance, and is held in a table. The calculation time is reduced for the positioning control of the processing device, and the sampling period can be shortened.

Further, in order to realize the control, a position signal generation circuit is provided to know the position of the control target. When the output of the position signal generation circuit can be directly taken into the arithmetic processing device, the arithmetic processing device performs the operation of the positive cast control combined with the double robust control, and outputs the operation result to the D / A converter. By driving the positioning control mechanism with the output value, positioning of the control target can be realized. With the above circuit configuration, the positive cast control combined with the dual robust control can be applied to the control target.

Further, in the above circuit configuration, when a position signal generated from the position signal generation circuit causes a large burden in the processing of the arithmetic processing device, a position number generation circuit is provided between the arithmetic processing device and the position signal generation circuit. With the above circuit, the processing load of the arithmetic processing can be reduced.

In the above circuit configuration, when the output of the position signal generation circuit cannot be directly captured by the arithmetic processing device, an A / D converter is provided between the arithmetic processing device and the position signal generation circuit. As described above, the output of the position signal generation circuit can be taken into the arithmetic processing unit.

Further, in the above circuit configuration, by providing the sample period stabilizing circuit, the position of the control target can be known for each accurate sample period.

Further, in the circuit configuration, an arithmetic processing device that performs an operation of a positive cast control in which an A / D converter that captures a position signal generated from a position signal generation circuit and a dual robust control are combined, and a control program or a table for the arithmetic processing device. ROM for storing values, RAM for the work area of the processing unit, etc., and a control output which is the calculation result of the processing unit.
Make the D / A converter an IC in one package. From the above,
The circuit area can be reduced.

Further, in the case where processing the position signal generated from the position signal generation circuit by the arithmetic processing unit in the IC becomes a heavy burden, the IC of one package including the position number generation circuit is included.
To As described above, the processing load on the arithmetic processing unit and the circuit area can be reduced.

〔Example〕

FIG. 1 is a diagram showing a case where an embodiment of the present invention is applied to positioning control of a magnetic head of a magnetic disk drive.
This will be described with reference to FIGS. 2, 3, 4, 5, 6, 7, 8, and 9. FIG.

FIG. 1 is a block diagram of a continuous positioning control system of a magnetic head when the present invention is applied to a magnetic disk drive. This time, the compensator is basically a regulator as an example. It goes without saying that servo or other control rules may be applied depending on the control target. This is because the control target for actually positioning the magnetic head 1, the compensator 2 for controlling the control target, and the control target for calculating the ideal behavior of the control target in real time are included in the compensator. Numerical model 3 is included. The meaning of each symbol is as follows.

u (t): control input of the control target at time t (T): control input of the numerical model of the control target at time t The above symbols are specifically considered as follows when a positioning control system of a magnetic head of a magnetic disk device is considered. Here, the VCM (Voice C
oil motor).

u (t): control current flowing to VCM at time t (T): Control current value to be added to the system in which the magnetic head positioning control system at time t is a numerical model The operation of the block diagram in FIG. 1 is as follows. Here, in this case, the control target is considered to be a secondary system for convenience of explanation. Of course, the control object can be selected from the analysis to select the most appropriate order. For example, consider a case where an instruction to move the magnetic head by n tracks is received from the host.
At this time, since the magnetic head is following following the target track, the position of the magnetic head is changed.
n, speed 0, the state variables of the controlled object and the numerical model of the controlled object Becomes From this, the control input (0) for the numerical model to be controlled is And the control input u (0) of the control object is Therefore From the above, the control input to be applied to the controlled object and the numerical model of the controlled object are as shown in Expressions (1.2) and (1.3). As a result, the controlled object and the numerical model of the controlled object are Here, from equations (1.1), (1.2) and (1.3), Since u (0) = (0), the difference between Expressions (1.4) and (1.5) is due to a modeling error when the control target is a numerical model. Actually, when the control target is a numerical model, an identification error of the control target such as a nonlinear element is included. This error is Appears in the difference. To compensate for this difference Thus, the control input u (t) of the next control target is According to equation (1.6), the magnetic head moves to the target track while the control input to the control target is corrected, and control is performed so that the behavior difference from the numerical model of the control target disappears. Here, 1 / S is an operator of integration. To summarize the above into a general system, Becomes The above is the regulator combined with the dual robust model following control. The control includes: Compensation is easy, so compensator design is easy.
By the way, the feedback coefficient of the state variable Accordingly, magnetic heads having various characteristics can be positioned. In order to control the positioning of the magnetic head, first, the numerical model of the control Is selected, and one vertex of the simple vibration is set as the initial point and the other vertex is set as the target point, and the magnetic head is moved from the initial value to the target point by simple vibration. Next, after the magnetic head reaches the target point, the numerical model of the control object reaches the target value and the speed becomes zero, Therefore, Therefore, FIG. Is used as a feedback coefficient. Therefore, By doing so, fast positioning control is achieved. This time, as described above, since the compensator is basically a regulator, the regulator control is used before and after the target point where the control is switched. However, in this combination, various control rules such as a regulator and a servo, a servo and a regulator, and a servo and a servo may be combined according to a control target. Next, the feedback coefficient of the state variable of the control by the regulator to make the numerical model to be controlled a simple oscillation The method for determining is described.

Since the control method is a regulator this time, Therefore, State variables Then Where L ^-1 is the symbol of the Laplace inverse variable From the relationship, in the case of simple vibration, If you can put it, By the way, the moving track amount from the track currently followed by the magnetic head to the destination track is assumed to be n tracks. Initial value of state variable Is from the position n and speed 0 of the magnetic head because the magnetic head is following. In other words, Equations (1.8), (1.9), (1.11), and (1.
12) From equation (1.13), Response is amplitude n / 2, period 2π / ω, position
₁ (t) is a simple oscillation whose phase is advanced by -π / 2 with respect to velocity ₂ (t). Therefore, when it is desired to move the position ₁ (t) by n track seeks, the following position ₁ (0) of the magnetic head is set to n / 2, the target position.
_{If 1} (t) is associated with -n / 2 by the numerical model of the control object, the magnetic head reaches the target position and the speed becomes 0 at time t = π / ω from equation (1.13). At this point, the control law has good stability If the regulator is switched to the above-described regulator and the position of the numerical model to be controlled is associated with 0, the control is terminated because the position is 0 and the speed is 0. Thereby, the positioning of the magnetic head becomes extremely fast. Good stability Is determined as follows. Feedback coefficient of state variable of control by regulator , The controlled object is given by equation (1.8) Because of the relationship, as soon as possible To stabilize The real part of the solution is negative and the real part is as large as possible. You can decide. In reality, here, Is u (t) from the control current flowing through the VCM at time t.
Due to hardware limitations, Cannot be taken too much. As described above, the control for generating a simple vibration between the initial value and the target value is called positive cast control.
When the positive cast control is directly applied to the control target,
Because the magnetic head often does not reach the target position or the speed does not reach 0 at the switching point of the control rule due to unknown disturbance, parameter variation of the controlled object, or identification error of the controlled object, after the switching, May take a long time to converge or even lose synchronism. Therefore, it is difficult to apply the above-mentioned positive cast control to an actual control object having many uncertain factors as it is. Therefore, as shown in FIG. 1, the numerical model of the controlled object is subjected to positive cast control, and the difference between this state variable and the state variable of the actual controlled object is fed back to the actual controlled object, whereby the actual controlled object is controlled. Consider a control method that matches the behavior of the numerical model.
The positioning control of the magnetic head is a positive cast control in which the continuous double robust model following control described above is combined. Here, when the difference between the output of the state variable of the numerical model of the controlled object and the actual state variable of the controlled object is fed back, May be determined as follows. From FIG. from now on, Here, if the numerical model of the controlled object substantially represents the controlled object, Becomes Equation (1.14) is derived from Equation (1.8) Therefore, such that equation (1.15) does not diverge, Would be a good choice. That is, The real parts of the solutions of are all less than or equal to 0 You can choose However, in reality, the above stability is good In the same way as Then, since there is a hardware limit of the control current u (t) flowing to the VCM, Value cannot be taken. According to the present embodiment, applying the positive cast control combined with the continuous double robust model following control described above to the positioning control of the magnetic head is suitable for the high-speed positioning control of the magnetic head having many uncertainties. It is a suitable control.

FIG. 2 is a block diagram of a discrete positioning control system of a magnetic head when the present invention is applied to a magnetic disk drive. The block diagram has the same configuration as that of FIG. The meaning of each symbol is the same as in FIG.
Here, when the relationship between the discrete system and the continuous system is discretized by zero-order hold, t = iT (T: sample period) (2.1) Also, the feedback coefficient Is from digital redesign (However, when T is small enough) (If T is sufficiently small), a compensator that behaves the same in a discrete system as in a continuous system can be designed. Further, Z ^-1 is an operator that delays the numerical value by one. The function of the block diagram can be represented by the following general system, as in FIG.

As in FIG. 1, the feedback control for the simple oscillation in the discrete system is obtained from the equation (2.3) for the positioning control of the magnetic head. Is selected, first, the magnetic head, from the track following the current track to the destination track, is corrected according to the state variables of the position and speed of the controlled object by the dual robust model following control, but basically It moves with simple vibration of positive cast control. When the magnetic head reaches the destination track, the speed of the magnetic head becomes 0,
At this point, the control law is well-stabilized by equation (2.4). , And the position of the numerical model to be controlled is associated with 0, so the control ends because the position is 0 and the speed is 0. Thereby, the positioning of the magnetic head becomes extremely fast. According to the present embodiment, applying the positive cast control combined with the discrete double robust model tracking control described above to the positioning control of the magnetic head is a high-speed positioning control of the magnetic head having many uncertainties. The control is suitable for

FIG. 3 is a diagram showing a relationship between a position signal of a magnetic head of a two-phase servo of a general magnetic disk device and a track pulse signal generated from the position signal. The position signal is generated from the positioning information of the magnetic head recorded on the disk 5, and the magnetic head 4 outputs a Normal signal (POSN) at which the output becomes zero level on the track 6 and the magnetic head outputs the signal at the center between the tracks. Is a quadrature signal (POSQ) that is at the 0 level. In addition, in order to speed up the writing of the magnetic head positioning information to be recorded on the disk, the conventional recording of the magnetic head positioning information on the disk with the track width is now performed with twice the track width. There is a way to do that. In this case, the Normal signal and the Quadra signal alternately become 0 level on the track. That is, the two signals go to the 0 level every other track. There is also a method of creating a position signal as described above. By adding and subtracting the two outputs, a signal (POS-ADD) shifted by / 4 track from the Normal signal and 1/4
Two of the track shifted signals (POS-SUB) are created. By passing each of the four signals through a comparator,
Track pulse signals (N-OUT, Q-OUT, ADD-OUT, SU
B-OUT) is also made. As described above, four types of positioning signals,
1 and 2 using four types of track pulse signals.
An example of a circuit configuration to which the positive cast control combined with the dual robust model tracking control shown in the figure can be applied will be described below. Of course, if the output pattern of the positioning signal changes, there is no problem in taking a circuit configuration that matches the pattern.

FIG. 4 is a circuit configuration diagram 1 of a positioning control system of a magnetic disk drive when either one of servo surface servo information and data surface servo information is used for magnetic head positioning control information. As shown in FIG. 3, the circuit configuration is such that a positive cast control in which discrete double robust tracking control is combined using a positioning signal and a track pulse signal generated from the positioning signal can be applied. As signals to be used, two signals, ADD-OUT and SUB-OUT, of the track pulse signals are used as position signals from the track currently being followed by the magnetic head to the destination track. By using the two signals, the position signal does not change for ± 1/4 track from the center of the track where the magnetic head is located, so that the two-phase clock generation circuit and the counter circuit using the two signals can easily use the magnetic signal. The track position of the head can be grasped. Further, in order to follow the magnetic head after reaching the target track, a positioning signal POSN is used as a position signal. The POSN signal is almost zero when the magnetic head is completely on the target track and the value of the counter circuit using the two signals ADD-OUT and SUB-OUT does not change. Is a straight line, so it is suitable for a magnetic head positioning signal. this
By processing the POSN signal in a discrete system using an A / D converter, a large portion can be shared with a magnetic head positioning control circuit using a track count circuit based on the two signals ADD-OUT and SUB-OUT. A circuit configuration of a discrete system of the positioning control system shown in FIG. 4 configured according to the above design policy will be described below. First, the magnetic head 4 is
Reads the positioning information of the magnetic head recorded in the. Position signal generation circuit 9 from the read positioning information
Thus, a position signal and a track pulse signal generated based on the position signal are generated. As described above, the position signal is used as a position signal for the magnetic head to follow the target track stably, and the track pulse signal is used for moving the magnetic head from the track currently following to the target track. Used for position signals. A track number generating circuit 10 as a position number generating circuit generates a number corresponding to the current track number of the magnetic head from the track pulse. The number is taken into the microcomputer 13 as an arithmetic processing unit in accordance with an instruction to take in data at regular intervals output from the sample period stabilizing circuit 11. According to this value,
The process of the positive cast control in which the double robust model following control described above is combined is performed, and the result is output to the D / A converter 14. The value output to the D / A converter is subjected to a filtering process such as a resonance countermeasure of the positioning mechanism of the magnetic head by the filter 15, and the output is converted to VCM (V
(Oice Coil Motor) The driver 16 controls the positioning of the magnetic head. When the magnetic head enters a quarter of the target track, a position signal is used as a magnetic head positioning signal. Sample period stabilization circuit
The position signal converted by the A / D converter 12 is taken into the microcomputer 13 in accordance with an instruction to take in data at regular intervals issued from the microcomputer 11. In the microcomputer, the processing of the regulator using the stable feedback coefficient described so far is performed, and the result is output to the D / A converter 14, and hereinafter, the positive cast control combined with the dual robust model following control is performed. The same processing as in the case is performed. Of course, the regulator processing in the microcomputer may be changed to another control processing in order to accurately position the magnetic head according to the control target. According to this embodiment, since the positive cast control combining the discrete double robust model following control can be applied to the magnetic head positioning control, high-speed positioning control of the magnetic head having many uncertain elements can be realized. Of course, this circuit configuration is an example, and the track number is directly generated by the microcomputer without the track number generating circuit and the track number is generated in the microcomputer.
Or, even if the sampling period is not constant,
Various circuit configurations are conceivable, such as changing the arithmetic processing formula, but if positive cast control combining dual robust model following control can be applied, there is no problem to change the circuit configuration according to the control target. .

FIG. 5 is a circuit configuration diagram 2 of a positioning control system of the magnetic disk drive in the case where both information of servo surface servo and information of data surface servo are used for the positioning control information of the magnetic head. The configuration is basically the same as that of FIG. This time, the increased circuit is now a position signal generation circuit for data surface information.
A / D converter. This is because, in order to perform accurate positioning of the magnetic head, when the magnetic head follows, the positioning of the magnetic head is performed based on the magnetic head positioning information read from the magnetic head for reading and writing data, that is, the data surface information. This is a circuit for enabling control. When the magnetic head moves from the track following the current track to the target track, until the magnetic head enters within 1/4 track of the target track,
This is the same as in FIG. When the magnetic head enters within one-fourth of the target track, positioning control is performed using data surface information serving as positioning information of the magnetic head read from the magnetic head to be read / written. A position signal is generated by the position signal generating circuit from the data surface information, and the position signal converted by the A / D converter is fetched into the microcomputer in accordance with a data fetching instruction at regular intervals issued by the sample period stabilizing circuit. In the microcomputer, the regulator process of the stable feedback coefficient described above is performed, and the result is output to the D / A converter. As described above, accurate positioning control of the magnetic head can be realized. Of course, the regulator process in the microcomputer may be changed to another control process in order to accurately position the magnetic head according to the control target.
Alternatively, when the magnetic head enters within 1/4 track of the target track, a method using two pieces of servo information read from the servo surface and data surface information read from the data surface is also conceivable. In this case, according to the instruction to take in data at regular intervals issued by the sample period stabilizing circuit, the position signal created from the servo surface information and the position signal created from the data surface information are converted by the A / D converter, respectively. Import to microcomputer. In the microcomputer,
The filter calculation is performed so that the servo surface information is effective at high frequency and the data surface information is effective at low frequency, and the result is output to the D / A converter. As described above, accurate magnetic head positioning control using two position signals can be realized. Of course, the filter processing in the microcomputer may be changed to another control processing in order to accurately position the magnetic head according to the control target. According to the present embodiment, it is possible to apply the positive cast control in which the discrete double robust model following control is combined with the magnetic head positioning control, and it is possible to realize the accurate magnetic head positioning control. High-speed and high-accuracy positioning control of many magnetic heads can be realized.

FIG. 6 is an example of a constant sampling period circuit diagram. The meaning of each symbol is as follows. The prefix of the symbol CS indicates that it is a chip select signal generated from the address bus of the microcomputer. Flag is a signal that becomes active after the sample cycle time set by the microcomputer. Carry is a signal that becomes active only at the sample cycle time. ▲ ▼ is a signal for opening a gate for outputting a Flag output on the data bus line so that the microcomputer knows whether or not the sampling period has elapsed. ▲ ▼ is a signal for the microcomputer to reset because the Flag remains Active after the elapse of the sample period. ▲
▼ is a latch signal for the microcomputer to make the counter circuit remember the sample period. ▲ ▼ is a Write gate signal of the microcomputer when data is output from the microcomputer. D0 to D7 are data buses of the microcomputer. ▲
▼ is a reference clock for counting up the counter circuit. This operation is as follows. As an example of description, ▲ is 1 MHz, and the sampling period is 100 μs. From the microcomputer, set ▲ ▼ to Active and output 256−100 = 156 to the data bus and latch it to TTL374. This value is an initial value of a counter that can count up to 1 to 256 using two TTL 161s. When the value of the counter exceeds 255, a carry signal is output, the value latched in the TTL 374 is loaded into the counter, and the counter becomes an initial value. When the carry signal is output, the signal is latched by using two D-flip-flops to generate a flag signal. Once this Flag signal becomes Active, the microcomputer
It remains Active unless reset by ▼.
Therefore, by checking the flag by the microcomputer, the sample cycle is not missed for the arithmetic processing of the microcomputer, and the software of the microcomputer is easily designed. When the microcomputer knows that the flag has become active with ▲ ▼, it is necessary to reset the flag with ▲ ▼. However, since the flag does not affect the counter operation, the microcomputer can know an accurate sample period if the time for resetting the flag with ▲ ▼ is within the time until the next carry. According to the present embodiment,
The sample period can be set from the microcomputer, and the sample period can be known almost accurately even if the microcomputer does not always look at the sample period. Of course, the circuit may be changed according to the control target, such as by connecting Carry to the interrupt of the microcomputer and forcibly interrupting it, or increasing the count number.

FIG. 7 is an example of a track number generation circuit diagram. The meaning of each symbol is as follows. Carry is a signal that becomes active every sample period specified by the microcomputer from the counter circuit of the constant sample period circuit diagram of FIG. AD
D-OUT and SUB-OUT are track pulses generated based on the position signal as described with reference to FIG. CLOCK is a clock serving as an operation reference of this circuit. Flag is a signal that becomes active after the sample cycle time set by the microcomputer as described in FIG. DO
D15 is a data bus of the microcomputer. ▲ ▼ is C
This is a reference clock created from LOCK. ▲ ▼
6 is the same signal as in FIG. 6 and is a signal for opening a gate for outputting the position of the magnetic head in the latest sample period on the data bus line when the microcomputer wants to know the position of the magnetic head. ▲ ▼ is a signal for clearing the up / down counter for counting the current position of the magnetic head. ▲ ▼ is a Write gate signal of the microcomputer when data is output from the microcomputer. This operation is as follows. As an example of description, CLOCK is 8Mh
z, therefore, in this circuit, the reference clock is 1 MHz, the position where the magnetic head is currently following is track 0,
Now consider the case where the magnetic head moves 10 tracks ahead. First, the microcomputer clears the up / down counter constituted by the TTL 193 to 0 using the ▲ ▼ signal in order to initialize the track count. The microcomputer calculates the control current u (t) required for the VCM for the magnetic head to move 10 tracks ahead according to the theory of the positive cast control that combines the dual robust model following control, and calculates the VCM.
Here, the value of the up / down counter is used as the position information of the control theory. The value is created as follows. 8MHz clock to TTL1
This is a 1MHz reference clock made by dividing frequency by 61.
The ADD-OUT and SUB-OUT of the track pulse are sliced by TTL174 and some logic circuits as shown in Fig.
Make a down signal. The up / down counter is operated by four TTLs 193 based on the up / down signal. The up / down counter value is calculated by two Carry signals shown in FIG.
Latched by TL374. Here, since the phases of the reference clocks in FIGS. 6 and 7 are shifted by 50%, Carr in FIG.
If the circuit is designed in consideration of the delay of the signal that yields y,
There is no need to worry that the TTL374 latches an indefinite value while the four TTL193 up / down counters are just up or down. As explained in Fig. 6, the microcomputer
When checking the Flag signal, a ▲ ▼ signal is issued. As shown in Fig. 7, connect the Flag to bit15 of the data bus of the microcomputer, connect the rest to TTL374, and connect ▲ ▼ to TTL374.
If the microcomputer is connected to the output control terminal, the microcomputer can take in the Flag information and the information on the current position of the magnetic head with one command, and the efficiency is high. With this circuit configuration, when the magnetic head reaches the target track 10 tracks ahead, 4
The up / down counter value by the TTL193 is 20 in decimal. When the microcomputer knows this value,
By taking in the data from the A / D converter and following the magnetic head, high-speed positioning control of the magnetic head can be realized according to the theory of the positive cast control in which the dual robust model tracking control is combined. According to the present embodiment, the position of the magnetic head can be accurately known for each sample period from the up / down counter value operated by the up / down signal generated by the track pulses ADD-OUT and SUB-OUT. Of course, in the above circuit configuration, the speed information of the magnetic head necessary for the positive cast control combined with the dual robust model follow-up control is simulated using a backward difference or the like in the microcomputer, or another circuit is added. It doesn't matter. Also, this time, the microcomputer has a data bus width of 16 bits, but the circuit may be changed as necessary. Further, depending on the number of tracks of the magnetic disk device, there is no problem in changing the counted value of the up / down counter.

FIG. 8 is a diagram of an experimental result of the positive cast control in which the positioning control of the conventional magnetic head and the dual robust model following control are combined. In this case, 273 tracks, which is 1/3 full track, which is close to the average access time of the magnetic disk drive using the moving amount of the magnetic head, are used. The experimental results show that the upper signal is POSN, which is a position signal, and the lower signal is u (t), which is a control current. The scale of both figures is POSN 6.6 × 10 ⁻⁶ m / DiV (when following) u (t) 2A / DiV Time 5 × 10 ⁻³ S / DiV. FIG. 8 (a) shows a conventional control method. When the magnetic head is following, a round-trip transmission of a magnetic head positioning control system using a phase lead / lag compensation, a low-pass filter, a notch filter for avoiding mechanical resonance, and the like. The function is adjusted so as to obtain desired characteristics in consideration of the response of the magnetic head. When the magnetic head is moving to the target track, u (t) is output according to a control current table according to the moving amount of the magnetic head in the microcomputer. The table is determined to some extent from experience in consideration of the maximum speed at which the magnetic head can move stably. FIG. 8 (b) shows a case where the positive cast control combined with the dual robust model follow-up control is used for the magnetic head positioning control described so far. As is clear from FIG. 8, the conventional control method takes about 24 ms for the positioning control, whereas the positive control combined with the dual robust model follow-up control takes about 19 ms, and about 20% of the magnetic head is used. Positioning control has been sped up.

FIG. 9 is a block diagram of an IC for controlling the positioning of the magnetic head of the magnetic disk drive. This is because the A / D converter that takes in the position signal generated from the position signal generation circuit and the arithmetic processing unit 19 that performs the operation of the positive cast control that combines the dual robust control and the control program and the table value for the arithmetic processing unit A ROM 17 to be stored, a RAM 18 such as a work area of the arithmetic processing device, and a D / A converter for outputting a control output as an arithmetic result of the arithmetic processing device are integrated into one package IC. According to this embodiment, it is possible to realize an IC suitable for positioning control and capable of reducing the circuit area. Of course, when processing the track pulse of the position signal generated from the position signal generation circuit by the arithmetic processing unit becomes a heavy burden, change according to the control target, such as including a track number generation circuit into one package IC. It doesn't matter what you do.

〔The invention's effect〕

According to the present invention, in the positioning control device, applying the positive cast control combined with the dual robust model follow-up control has an effect of speeding up the positioning of the control target. In particular, by using the above control for the positioning control of the magnetic head of the magnetic disk drive, there is an effect of shortening the positioning control time by as much as 20% as compared with the conventional control method.

In addition, in the positive cast control in which the dual robust model following control is combined, the operation of the behavior of the reference model to be controlled is calculated for each sample period, thereby reducing the overall program capacity of the arithmetic processing device. is there.

Further, in the positive cast control in which the dual robust model following control is merged, the calculation of the behavior of the reference model to be controlled is calculated in advance for each sample period in accordance with the moving distance and is held in a table, thereby performing the calculation processing. The calculation time for the positioning control of the apparatus can be shortened, and the sampling period can be shortened.

Further, in order to realize a positive cast control in which the dual robust model following control is combined, a position signal generating circuit for knowing a position of a control target is provided, and an output of the position signal generating circuit can be directly taken into an arithmetic processing unit. In the case, the arithmetic processing unit performs the operation of the positive cast control combined with the double robust control, outputs the operation result to the D / A converter, and drives the positioning control mechanism with the output value to perform the positioning of the control target. Do. With the above circuit configuration, there is an effect that the positive cast control combined with the dual robust control can be applied to the positioning control device.

Further, in the above circuit configuration, when a position signal generated from the position signal generation circuit causes a large burden in the processing of the arithmetic processing device, a position number generation circuit is provided between the arithmetic processing device and the position signal generation circuit. The above circuit has the effect of reducing the processing load on the arithmetic processing unit.

In the above circuit configuration, when the output of the position signal generation circuit cannot be directly captured by the arithmetic processing device, an A / D converter is provided between the arithmetic processing device and the position signal generation circuit. As described above, there is an effect that the output of the position signal generation circuit can be taken into the arithmetic processing unit.

Further, in the above-described circuit configuration, by providing the sample period stabilizing circuit, there is an effect that the position of the control target can be known for each accurate sample period.

Further, in the circuit configuration, an arithmetic processing device that performs an operation of a positive cast control in which an A / D converter that captures a position signal generated from a position signal generation circuit and a dual robust control are combined, and a control program or a table for the arithmetic processing device. ROM for storing values, RAM for the work area of the processing unit, etc., and a control output which is the calculation result of the processing unit.
Make the D / A converter an IC in one package. From the above,
This has the effect of reducing the circuit area.

Further, when it becomes a heavy burden to process the position signal generated from the position signal generation circuit by the arithmetic processing unit in the IC, the IC of one package including the position number generation circuit is also included. As described above, there is an effect that the processing load on the arithmetic processing device is reduced and the circuit area is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a continuous positioning control system of a magnetic head according to one embodiment of the present invention, FIG. 2 is a block diagram of a discrete positioning control system of a magnetic head according to one embodiment of the present invention, FIG. 3 is a diagram showing a relationship between a position signal of a magnetic head of a two-phase servo of a general magnetic disk device and a track pulse signal generated from the position signal, and FIGS. 4 and 5 are diagrams of a positioning control system of the magnetic disk device. 6 is a circuit diagram showing a constant sampling period, FIG. 7 is a circuit diagram of a track number generation circuit,
FIG. 8 is a diagram of an experimental result of a positive cast control in which a conventional magnetic head positioning control and a dual robust model following control are combined, and FIG. 9 is a block diagram of a magnetic head positioning control IC of a magnetic disk device. is there. 1 ... Control target, 2 ... Compensator, 3 ... Numeric model of control target, 10 ... Track number generation circuit, 11 ... Sampling period constant circuit.

Continued on the front page (72) Inventor Tetsushi Kawamura 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Microelectronics Device Development Laboratory, Hitachi, Ltd. Odawara Plant (56) References JP-A-2-17513 (JP, A) JP-A-64-48104 (JP, A) JP-A-1-314306 (JP, A) JP-A-54-87368 (JP, A A) JP-A-64-29911 (JP, A)

Claims (6)

(57) [Claims] 1. A positioning control device for controlling a movement of a control target to a target position, a detection means for detecting the target position of the control target, and a movement from the current position of the control target to the detected target position. While receiving the correction according to the state variable of the position and speed of the controlled object by the double robust model following control, the speed becomes 0 when the vehicle arrives at the target position, and the distance between the current position and the target position is simply set. A positioning control device, comprising: moving means for performing positive cast control for moving by vibration. 2. The positioning control device according to claim 1, wherein the movement means moves the control target by performing a calculation of a behavior of a reference model of the control target to which the positive cast control is applied at every sampling period. A positioning control device characterized by performing the following. 3. The positioning control device according to claim 1, further comprising: a table storing a result of previously calculating a behavior of a reference model of a control target to which a positive cast control is applied, for each sample period; The positioning control device uses the result stored in the table. 4. The positioning control device according to claim 1, wherein the control target is a porcelain head moving on a disk, and the detecting means reads positioning information recorded on the disk, A positioning control device, which is a position signal generation circuit that outputs a position signal from the read positioning information. 5. The positioning control device according to claim 4, wherein said moving means includes a D / A converter for performing D / A conversion of said position signal, and said magnetic head according to an output of said D / A converter. A positioning control device comprising a positioning control mechanism for controlling movement. 6. The positioning control device according to claim 1, wherein the positioning control device includes a single IC including the detection unit and the moving unit.