JPH07213085A - Positioning device - Google Patents

Abstract

PURPOSE:To obtain a positioning device in which a control operation is performed by removing the influence of a disturbance such as an error, a noise or the like contained at a speed detection stage and which can perform a positioning control operation at high speed and with high accuracy. CONSTITUTION:In a positioning device, the speed and the position of an object 1 to be controlled are detected by a speed detection means 2, a control amount (u) is given to the object 1, to be controlled, by feedback control on the basis of a target speed profile so as to control the speed and the position, and the object 1 to be controlled is moved to a target position. In the positioning device, a speed estimation means 5 by which the present speed of the object 1 is estimated on the basis of a detection speed V detected by the speed detection means 2 and on the basis of the control amount (u) is installed. In addition, a control and operation means 4 by which the control amount (u) with reference to the object 1 is computed on the basis of an estimation speed Vobs estimated by the speed estimation means 5 is isnatlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning device for performing high-speed and highly accurate positioning control of a read head in an ODD (optical disk device), an HDD (hard disk device), or a drive unit in a robot. Relates to a feedback control type positioning device that detects a speed and a position and performs a control calculation.

[0002]

2. Description of the Related Art For example, in an ODD or HDD, when accessing a target track of a disk, it is necessary to move a read head (optical head or magnetic head) to the target track at high speed and accurately.

Therefore, as a general method of moving the read head, a target velocity profile is set in advance, the current position and the moving velocity of the read head are detected, and the difference between the current position and the target position (residual distance). ) Is input, the target speed is calculated according to the target speed profile described above, and a predetermined control calculation is performed by using the calculated target speed and the detected moving speed as input, and the control amount is calculated. Follow-up control is performed so that the speed becomes equal to the speed. When approaching the target track, high-speed and high-accuracy positioning control can be performed by switching from speed control based on the target speed profile until then to position control to the target track position, or by changing the target speed profile. I am trying to do it.

In such control, the detection speed and the detection position must be accurate. However, in reality, there is a possibility that false detection may occur due to noise or the accuracy of the detection system. If a control calculation is performed using data erroneously detected in this way and a control amount is obtained, an abnormal control amount will be given, which will not only prevent high-speed and high-precision positioning control, but also cause runaway. It may happen.

Incidentally, it is desirable that such erroneous detection can be removed at the stage of detection, but if the configuration is such that it is removed at the stage of detection, there is a disadvantage that the cost of the device increases, and if it is detected, Even if it is a structure that can be removed at the above-mentioned stage, erroneous detection may still occur depending on the use environment and changes with time, and it is incomplete.

As an improvement plan considering such a point, there is one disclosed in Japanese Patent Laid-Open No. 4-281273. This is the operation of the device by comparing the position signal waveform and the current waveform in the accessing state with feedback and compensating for the difference in consideration of vibrations and disturbances that cause defective positioning operations and self-heating of the motor itself. The control suitable for the state is performed.

Further, as proposed by the applicant of the present invention, there is also one in which an accurate speed control is performed by estimating the speed and using the estimated information to avoid an abnormal value of the detected speed. More specifically, the target speed determined based on the detection position and the target position detected by the speed detecting means,
In a positioning device including control means for calculating a control amount based on the difference between the detection speed of the read head detected by the speed detection means and controlling the read head drive motor, the control amount and the detected position or the detected speed are calculated. Estimating means for estimating the current position or current speed of the read head as an input and outputting an estimated value is compared with the detected position or detected speed and the estimated value, and if the difference is larger than a predetermined value, the detected position or detected A judgment means for judging the speed as an abnormal value is provided.

[0008]

However, in the case of the former Japanese Patent Laid-Open No. 4-281273, the influence of the detection speed error due to noise or disturbance in the speed detection stage is not taken into consideration, and high-speed and high-accuracy positioning is performed. It is incomplete in controlling.

Further, the latter method proposed by the present applicant is effective for sudden disturbances, etc., but does not consider errors in the detection system, chronically added noise, etc.
After all, it is incomplete in performing high-speed and highly accurate positioning control.

In consideration of these points, the present invention considers not only vibration and disturbance and self-heating of the controlled object itself such as a motor, but also detection speed error due to noise and disturbance in the speed detection stage. An object of the present invention is to provide a positioning device capable of performing accurate and high-speed position control without being affected.

[0011]

According to a first aspect of the present invention, the speed and the position of the controlled object are detected by the speed detecting means, and the speed is controlled by giving a controlled variable to the controlled object by feedback control based on the target speed profile. In a positioning device that performs control and position control to move the controlled object to a target position, speed estimation that estimates the current speed of the controlled object based on the detected speed detected by the speed detecting means and the control amount. Means are provided, and control calculation means for calculating the control amount for the controlled object based on the estimated speed estimated by the speed estimating means is provided.

According to the second aspect of the invention, in addition to the structure of the first aspect of the invention, a speed correction means for correcting the estimated speed estimated by the speed estimation means is provided.

According to a third aspect of the present invention, in the configuration of the second aspect of the invention, the speed correcting means calculates the correction amount by executing trial control when the power is turned on.

According to a fourth aspect of the invention, in the configuration of the second aspect of the invention, the speed correction means has a storage section for calculating and storing the correction amount in advance.

According to a fifth aspect of the present invention, in the configuration of the second aspect of the invention, the speed control means adjusts the correction amount based on the difference between the target speed and the estimated speed at the time of executing the control.

[0016]

According to the present invention, speed estimation means for estimating the current speed on the basis of the detected speed and the controlled variable is provided, and the estimated speed estimated by the speed estimation means is used to control the control operation means. Since the amount is calculated and the operation of the controlled object is controlled, the influence of the disturbance such as error and noise included in the speed detection stage is eliminated, and the high-speed and highly accurate positioning control can be performed.

According to the second aspect of the present invention, since the speed correcting means for correcting the estimated speed estimated by the speed estimating means is provided, accurate and stable speed control canceling out the steady-state deviation that may occur by using the estimated speed. Is possible.

At this time, in the invention according to claim 3,
Since this control amount is calculated by executing trial control when the power is turned on, in addition to errors and noise in the detection stage, it is possible to correct errors in the estimated speed due to the operating environment and deterioration over time. Speed control is possible.

Further, in the invention according to the fourth aspect, since the correction amount is obtained and stored in advance, it is possible to perform the accurate control without being affected by the steady deviation without performing a special process. Can be relatively simple.

Further, in the invention according to claim 5,
The correction amount is adjusted by checking if any deviations remain based on the target speed and estimated speed information during actual control, so the correction amount can be adjusted due to the operating environment and deterioration over time. Therefore, the speed control can always be performed with the optimum correction amount.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. This embodiment corresponds to the invention described in claim 1 and is applied to, for example, a positioning device for an ODD read head (optical head), and a head drive seek motor 1 to be controlled is provided including this read head. Has been. A speed detecting section (speed detecting means) 2 for detecting the moving speed of the head drive seek motor 1 as the detected speed V is provided. Further, a control calculation unit (control calculation means) which calculates and outputs a control amount u for the head drive seek motor 1 in accordance with an output of a comparator 3 for obtaining a difference between a target speed Vref based on a predetermined target speed profile and an actual speed. 4 are provided. Further, a speed estimating unit (speed estimating unit) that outputs a speed obtained by removing noise and the like as an estimated speed Vobs using the control amount u calculated by the control calculating unit 4 and the detected speed V detected by the speed detecting unit 2 as input. Means) 5 are provided. The estimated speed Vobs output from the speed estimator 5 is given to the comparator 3 as an actual speed and is controlled so as to be equal to the target speed Vref. The control calculator 4 → head drive seek motor 1 → A feedback control system including the speed detection unit 2 → speed estimation unit 5 → control calculation unit 4 is formed in a loop. The target speed Vref is calculated by a known technique, and the calculation method is not particularly limited. For example, the target speed Vref is determined based on the difference between the current position of the head drive seek motor 1 (reading head) and the target position. The target speed Vref may be obtained with reference to the target speed profile of 1.

Here, the speed estimating unit 5 is configured as a digital compensator using a Kalman filter 6 as shown in FIG. 2, for example, and removes noise and the like from the control amount u and the detected speed V. The speed can be estimated. In the configuration shown in FIG. 2, for example, when a sinusoidal disturbance 7 is added to the output y (detection speed) of the controlled object such as the head drive seek motor 1 (schematically, the adder 8
), The actual detected speed V
As shown in FIG. 3, (sokudo) is output A and vibrates due to noise. Such detection speed V
(Sokudo) is the control amount u (seigyo d
enatu pwm) to the Kalman filter 6 through the multiplexer (Mux) 9 to perform arithmetic processing according to an arithmetic expression to be described later, and the demultiplexer (DeMux) 10
Then, as shown in FIG. 3, the signal from which the noise component is removed can be obtained as the estimated speed Vobs. The characteristic diagram shown in FIG. 3 shows that the Kalman filter 6 quickly converges even when the initial value is deviated.

The arithmetic expression in the above Kalman filter 6 is shown below. In the formula, i is a current value (calculated value), V is a speed (calculated value), u is a control amount that is a pwm output value, y is a measured output (speed), and Y with ^ is a filter output. Further, Af _ij , Bf _ij , Cf _ij , and Df _ij are each calculated by a discrete Kalman matrix.

[0024]

[Equation 1]

As described above, according to this embodiment, the detection speed V
A speed estimation unit 5 that estimates the speed based on the control amount u and the control amount u is provided, and the control calculation unit 4 calculates the control amount u using the estimated speed Vobs estimated by the speed estimation unit 5 as the actual speed to drive the head. Since the operation of the seek motor 1 is configured to be controlled, the control is performed by removing the influence of disturbances such as errors and noise included in the speed detection stage, and high-speed and highly accurate positioning control can be performed.

Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those shown in the above-mentioned embodiments are designated by the same reference numerals (the same applies to the following embodiments). This embodiment corresponds to the invention described in claims 2 and 3,
The configuration shown in FIG. 1 is obtained by adding a speed correction unit 13 including a deviation detection unit 11 and a target speed correction unit 12. In the case of the configuration of the above-mentioned embodiment, the influence of noise or the like generated at the detection stage can be removed by controlling using the estimated speed Vobs, but the error of the estimated speed due to the use environment or deterioration with time is regarded as a steady deviation. There is a concern that it will remain. The speed correction means 13 is for correcting such a steady deviation to obtain an accurate speed. The target speed correction unit 12 is interposed on the input side of the target speed Vref to the comparator 3, and the target speed Vref is corrected to the corrected target speed Vre.
It is corrected to fc and input to the comparator 3. The deviation detecting unit 11 includes the speed estimating unit 5 and the target speed correcting unit 1.
It is interposed between the target speed correction unit 12 and the steady-state deviation and detects the steady-state deviation.

In such a structure, first, trial control is executed when the power of the apparatus is turned on, and the target speed Vref at that time is controlled.
From the estimated speed Vobs and the estimated speed Vobs (see FIG. 5A), the deviation detection unit 11 detects a steady deviation, and the target speed correction unit 12 corrects the target speed Vref to the corrected target speed Vrefc based on the detected value. Specifically, as shown in FIG. 5B, the corrected target speed Vrefc is obtained by shifting the target speed Vref by the steady deviation. In this case, the target speed Vref
May be calculated or given in advance as a method of referring to the table. In the case of calculation, the predetermined value (the detected steady-state deviation amount) may be added and subtracted after the calculation, and the same may be applied to the case of the table reference method.
You may make it correct | amend the target speed data itself given beforehand.

Therefore, according to the present embodiment, the estimated speed Vob
Accurate and stable speed control that cancels the steady-state deviation that may occur by using s becomes possible. Especially, since the trial control is executed every time the power is turned on to calculate the correction amount,
In addition to the error and noise in the detection stage, the error in the estimated speed Vobs due to the use environment and deterioration over time can be corrected, and more accurate speed control can be performed.

A third embodiment of the present invention will be described with reference to FIGS. 6 and 7. The present embodiment also corresponds to the invention described in claims 2 and 3, but the speed correction means 15 including the estimated speed correction unit 14 and the deviation detection unit 11 provided in place of the target speed correction unit 12 of the embodiment is used. It is a thing. That is, in the second embodiment, the estimated speed Vobs is indirectly corrected at the target speed Vref, but in the present embodiment, the estimated speed Vobs is corrected.
The obs is directly corrected so as to become the corrected estimated speed Vobsc.

In such a structure, first, trial control is executed when the power of the apparatus is turned on, and the target speed Vref at that time is controlled.
From the estimated speed Vobs and the estimated speed Vobs (see FIG. 7A), the deviation detection unit 11 detects a steady deviation, and the estimated speed correction unit 14 corrects the estimated speed Vobs to the corrected estimated speed Vobsc based on the detected value. Specifically, as shown in FIG. 7B, a corrected estimated speed Vobsc may be obtained by shifting the estimated speed Vobs by the steady deviation.

Therefore, also in the case of the present embodiment, as in the case of the above-mentioned embodiment, accurate and stable speed control which cancels the steady-state deviation that can occur by using the estimated speed Vobs can be realized. Especially, since the correction amount is calculated by executing trial control every time the power is turned on, in addition to the error and noise at the detection stage, the error of the estimated speed Vobs due to the use environment and deterioration over time can also be corrected. Therefore, more accurate speed control becomes possible.

In these second and third embodiment methods, trial control is not performed when the power is turned on, the steady-state deviation is obtained in advance, the correction amount is calculated, and the correction amount is stored in a storage unit (not shown) such as a memory. It may be set (corresponding to the invention of claim 4). In this case, structurally, the velocity correction means 13 and 1 in which the deviation detection unit 11 is omitted in FIGS.
It may be configured as 5.

According to this, since the correction amount is obtained and stored in advance, accurate speed control can be performed without performing special processing such as trial control when the power is turned on, and a configuration including software can be comparatively performed. Can be simple. In addition, the required memory capacity may be small, the calculation processing time may be fast, and it is suitable for high speed control.

Further, the target speed Vref and the estimated speed Vobs at the time of actual control execution are stored in a memory or the like, the difference between these target speed Vref and the estimated speed Vobs is obtained, and the deviation still remains. In such a case, the speed correction means 13 and 15 for adjusting the correction amount (the target speed Vref or the estimated speed Vobs may be used) may be configured (corresponding to the invention of claim 5).

According to this, the correction amount is adjusted by checking whether any deviation remains based on the speed information at the time of actual control execution, so that the correction amount changes due to the use environment or deterioration over time. Therefore, the speed control can always be performed with the optimum correction amount.

[0036]

According to the first aspect of the invention, the speed and position of the controlled object are detected by the speed detecting means, and the speed control is performed by giving the controlled variable to the controlled object by the feedback control based on the target speed profile. In a positioning device that performs position control and moves the controlled object to a target position, a speed estimation means that estimates the current speed of the controlled object based on the detected speed detected by the speed detection means and the control amount. Since the control calculation means for calculating the control amount for the control target based on the estimated speed estimated by the speed estimation means is provided, the control which removes the influence of the disturbance such as error and noise included in the speed detection stage Therefore, high-speed and highly accurate positioning control can be performed.

According to the second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the speed correcting means for correcting the estimated speed estimated by the speed estimating means is provided. Accurate and stable speed control that cancels possible steady-state deviation can be performed.

According to the third aspect of the present invention, in the configuration of the second aspect of the invention, since the speed correcting means calculates the correction amount by executing the trial control when the power is turned on, the error in the detection stage and the In addition to noise, errors in the estimated speed due to the use environment and deterioration over time can be corrected, and more accurate speed control can be performed.

According to the invention of claim 4, in the structure of the invention of claim 2, since the speed correction means has a storage unit for calculating and storing the correction amount in advance, the steady-state deviation can be achieved without any special processing. It is possible to perform accurate control that is not affected by, and to make the configuration relatively simple.

According to a fifth aspect of the present invention, in the configuration of the second aspect of the invention, the speed control means for adjusting the correction amount based on the difference between the target speed and the estimated speed at the time of executing the control is used as the speed control means. Since the deviation is left to be checked based on the target speed and estimated speed information, the correction amount is adjusted so that changes in the correction amount due to the operating environment and deterioration over time can be dealt with, and it is always optimal. Speed control can be performed by the correction amount.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a specific block configuration diagram showing an example in which a Kalman filter is used in a speed estimation unit.

FIG. 3 is a characteristic diagram showing outputs before and after filtering.

FIG. 4 is a block diagram showing a second embodiment of the present invention.

FIG. 5 is a velocity characteristic diagram showing a correction process.

FIG. 6 is a block diagram showing a third embodiment of the present invention.

FIG. 7 is a velocity characteristic diagram showing a correction process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control object 2 Speed detection means 4 Control calculation means 5,6 Speed estimation means 13,15 Speed correction means

Claims (5)

[Claims] 1. A speed detection means detects the speed and position of a controlled object, and a feedback control based on a target speed profile gives a controlled variable to the controlled object to perform speed control and position control. In the positioning device for moving to the target position, a speed estimating means for estimating the current speed of the controlled object based on the detected speed detected by the speed detecting means and the control amount is provided, and the speed is estimated by the speed estimating means. A positioning device comprising a control calculation means for calculating the control amount for the controlled object based on an estimated speed. 2. The positioning device according to claim 1, further comprising speed correction means for correcting the estimated speed estimated by the speed estimation means. 3. The positioning device according to claim 2, wherein the positioning device is a speed correction device that executes a trial control when the power is turned on to calculate a correction amount. 4. The positioning device according to claim 2, wherein the positioning device is a velocity correction unit having a storage unit for calculating and storing a correction amount in advance. 5. The positioning device according to claim 2, further comprising a speed control means for adjusting a correction amount based on a difference between a target speed and an estimated speed at the time of executing the control.