JPH0444104A - Drive controller - Google Patents

Abstract

PURPOSE:To shorten the time needed for drive an object to be driven to its target position and at the same time to improve the control accuracy by storing the voltage data in a 2nd storage means in accordance with the shift extent of the object against the target position and reducing the effective voltage to be applied to a motor when the object gets closer to its target position. CONSTITUTION:The drive voltage data on a motor 1 is stored in a 2nd storage means in regard of the voltage control. Thus the drive voltage of the motor 1 is reduced by a voltage control means 5 with use of the voltage signals, i.e., the output of a calculation means 3 for the shift extent set against a target position and the output of the means 7 set in response to the output of the means 3. Meanwhile an optimum deceleration curve is stored in a 1st storage means 6 in regard of the velocity control. Then the control of velocity is carried out based on the shift velocity signal outputted from a velocity detection means 2 and the deceleration curve signal outputted from the means 6 storing a deceleration curve corresponding to the shift velocity signal of the means 2. Thus the time needed for drive of an object (photographing lens) to be driven to its target position and at the same time the control accuracy is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a drive control device, specifically, a drive device that drives a driven object by a motor, in which the driven object is accurately stopped at a target position. Regarding a control device.

[Prior Art] Drive devices that drive a driven object using a motor have been widely used in electronic devices in various fields. It is often used in focus adjustment devices, etc. In this type of automatic focus adjustment device, the technical means proposed in Japanese Patent Application Laid-open No. 153526/1988, which was previously filed by the applicant, stores the optimum deceleration curve of the photographic lens and compares the driving speed and deceleration curve. Then, the lens is decelerated (combination of on/off and short brake) along this curve (hereinafter referred to as curve control). Furthermore, in the above-mentioned curve control, an automatic focus adjustment device is disclosed as Japanese Patent Application Laid-Open No. 1-88412, which changes the on-time of the motor according to the moving speed of the photographic lens, thereby quickly stopping the photographic lens at the target position. has been done. Furthermore, two PI (photo ink printer) units are installed, and one PI unit is installed when the target position is far from the target position.
Specific output, when near the target position, two PI specific outputs,
A drive control device that improves the accuracy of the stop position by detecting each position is disclosed in Japanese Patent Application No. 2-4072 by the present applicant.
It is proposed in No. 3.

[Problems to be Solved by the Invention] In such a lens drive control device, one possible method for increasing the driving speed of the photographing lens is to increase the voltage applied to the motor. However, if you simply increase the applied voltage, there will be no problem with the above control with regard to off or brake operation, but
Problems arise with controllability when turned on. That is, when the voltage is high, the acceleration is greater than when the voltage is low, so the driving speed of the motor becomes too high, making it difficult to control the motor along the deceleration curve.

In particular, when starting a few pulses before the target stop position, if the voltage applied to the motor is high, the drive voltage 5 will increase over the time width t from time t1, as shown in FIG. 12A.
After starting the motor by applying V (linear Ω2□), PI
Even if the brakes are applied at the time t2 when the output signal rises, the speed is already too high, so the target position P1
It is possible to go beyond it. In this case, the motor must be further driven in the opposite direction, resulting in problems such as hunting of the photographing lens near the target position. On the other hand, if the voltage is low, as shown in Fig. 12B, after starting the motor by applying a driving voltage of 2.5 V (linear ρ2°) over a time width tb from time t3, the PI output signal If the brake is applied at the rising time t4, the motor can be stopped without passing the target position P2 since the motor speed is relatively low. Note that ρ24 has a longer period than PI output signal waveform 23, so it rotates at a slower speed. Therefore, the controllability for driving several pulses is improved, but the response when starting the motor is lower due to the lower voltage applied to the motor. It becomes slow and takes time to start rotating, which results in not being able to focus quickly.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a drive control device that solves the above problems, shortens the driving time when driving a driven object (photographing lens) to a target position, and enables highly accurate control. There is something to do.

[Means for Solving the Problems] The drive control device of the present invention, as shown in FIG. 1 illustrating its concept, includes a motor for driving a driven body to a target position, and a motor that detects the moving speed of the driven body. a speed detection means 2; a first storage means 6 for storing an optimal deceleration curve set according to the amount of movement to the target position in order to stop the driven body at the target position; Calculation means 3 detects the amount of movement of the body and calculates the amount of movement to the target position, and calculates the moving speed of the driven body and the amount of movement of the driven body based on the amount of movement to the target position calculated by the calculation means. a control means 4 that controls the energization state to the motor while comparing it with the deceleration curve; a second storage means 7 that stores motor drive voltage data set according to the amount of movement to the target position; and a voltage control means 5 for reducing the effective voltage applied to the motor based on the calculated movement amount to the target position and the voltage data stored in the second drive means. This is a characteristic feature.

[Function] In this drive control device, the output of the movement amount calculation means 3 to the target position and the motor drive voltage data from the second storage means 7 corresponding to the output are used to determine the target position, such as the focus position. With respect to the position, the effective voltage applied to the motor 1 is increased by the voltage control means 5 up to a predetermined pulse. From a predetermined pulse before the target position to the target position, the motor 1 is driven while performing voltage control and speed control. That is, regarding voltage control, since the drive voltage data of the motor 1 is stored in the second storage means 7, the output of the movement amount calculation means 3 to the target position and the corresponding second storage means 7
The voltage control means 5 lowers the driving voltage of the motor 1 based on the voltage signal output from the motor.

Regarding speed control, since the optimal deceleration curve is stored in the first storage means 6, the moving speed signal output from the speed detection means 2 and the deceleration curve corresponding thereto are also stored. Speed control is performed based on the deceleration curve signal output from the first storage means 6.

[Example] The present invention will be specifically described below with reference to the drawings. In the following embodiments, the drive control device according to the present invention will be explained using an example in which the drive control device according to the present invention is applied to a lens drive in an automatic focusing device mechanism of a camera, and the first embodiment will be explained below with reference to FIGS. 2 to 6. .

FIG. 2 schematically shows the configuration of an automatic focus adjustment device for a camera. In the figure, the CPU inside the camera body 10
13, object 1 measured by the distance measuring unit 14 by triangulation distance measurement.
When the distance information up to 2 is transmitted, the CPU 13 determines the amount of movement of the photographic lens 11 from the distance information, turns on the motor 1, and starts moving the photographic lens 11. The speed and amount of movement of the photographic lens 11 are fed back to the CPU 13 by an encoder 15 consisting of a photo ink printer or the like.

As shown in FIG. 3(A), the encoder 15 has a slit 17 of a rotating member that rotates as the motor 1 is driven.
and two pieces P118 and 19 placed across the passage of this slit 17. Then, in response to the rotation of the slit 17, as shown in FIG. 3(B), PI output signals 20 and 21 having mutually different phases are outputted from the first P118 and the second PJ19, respectively. It has become.

FIG. 4 is a circuit diagram of the drive voltage control circuit of the motor 1 that drives the photographic lens to the in-focus position.
/A conversion to control the voltage applied to the motor bridge circuit 24 by the transistor 23. The motor bridge circuit 24 includes two PNP transistors T rl and T
r3, and two NPN transistors T r2. T
r4. Note that the D/A converter 22 is not required in the duty control described later.

Regarding the operation of motor 1, as shown in Table 1 below,
By setting the input signal Q1 to "L" level and Q4 to "H" level, transistors T rl and T r4 are turned on, and input signal Q2 to "L" level and Q3 to "H" level.
” level and turns off transistors T r2 and T r3, the input signal Q1 is set to
” level, Q4 is “L” level, input signal Q2 is “H”
The level is reversed by setting Q3 to "L" level.

Table 1: When applying the brake, input signals Q1 to Q4 are set to “H”.
By setting the transistor T r2.
Both ends of the motor 1 are short-circuited by turning on T r4 and turning off T rl and T r3. When turning off, input signals Q, , Q3 are set to "H" level, and input signal Q
2. By setting Q4 to the "L" level, all transistors Tri to Tr4 are turned off and the motor 1 is not energized.

Figure 5 shows P in a full speed region that does not require speed control and in a control region where deceleration control is performed based on deceleration curve data.
It is a timing chart of an I output signal, a motor control signal, and a motor drive voltage.

In the full speed range, fast drive is required, so the motor drive voltage is set to 5.
I'm setting it to v. On the other hand, in the control region, the motor drive voltage is lowered to 3.75.2.5 V and 1.25 V in conjunction with the fall of the PI output signal, depending on the amount of movement to the target position. As a result, when driving the lens while controlling the control area with a curve, the brakes are applied too much near the target position, resulting in excessive deceleration, so even if motor 1 is turned on and accelerated, the target speed will not be greatly exceeded. can do.

Next, the control operation for driving the photographing lens in the CPU 13 will be explained using the flowchart shown in FIG.

When this program is started by operating the release switch or the like, the CPU 13 first outputs a distance measurement command to the distance measurement section 14 to perform AF distance measurement.

When the distance measurement data is received from the distance measurement section 14, the one-lens target position is converted into the number of encoder pulses (step Sl). After setting the motor drive voltage to 5V (see straight line Ω4 in FIG. 5 above) (step S2), the motor 1 is energized (step S3). After driving the motor, it is checked whether the photographing lens position is within a control range within a predetermined range from the target position (step S4), and the motor 1 is continued to be driven at a voltage of 5V until the photographing lens is within the control range. When the photographing lens reaches within the control range, the process advances to step S5 and the motor drive voltage is set as follows. That is, if the photographing lens is 2 pulses before the target position, 1.
25V (see straight line 111 in Figure 5 above), 2.5V before 3 pulses (see straight line g2 in Figure 5 above), and 3.75V before 3 pulses (line g in Figure 5 above).
(see 3) respectively.

As described above, the key point of the present invention is that when the photographing lens enters a control range within a predetermined range from the target position, the motor drive voltage is set according to the amount of movement to the target position. is read from the second storage means (see FIG. 1). Then, it is determined whether the photographing lens has reached one pulse before the target position (step S6), and if it has not reached one pulse before the target position, the moving speed and position of the photographic lens are The deceleration curve is compared with the deceleration curve data stored in the first storage means 6 (see FIG. 1), and the deceleration curve is controlled until it reaches one pulse before. Then, when the pulse reaches one pulse, a short brake is applied to the motor 1 (step S8), and this photographing lens drive control operation is completed.

The above is the explanation of the first embodiment. In this first embodiment,
As shown in FIG. 5, the driving range of the photographic lens is as follows:
It is roughly divided into a full speed region and a control region.In the full speed region, motor 1
The drive voltage applied to the control area is set to 5V, and in the control region, it is set to 3.75V depending on the amount of movement to the target position such as the focused point.
．． 5 V, 1.25 Vl: were set respectively. However, even in the control area, if it is far from the target position,
There are few problems even if the acceleration when the motor is turned on in curve control is large, but the closer the motor is to the target position, the more it is necessary to use a drive voltage that can reduce the acceleration.

Therefore, when the photographic lens enters the control range, motor 1
As a modification of the first embodiment, an example in which the drive voltage applied to the motor is continuously changed will be explained below with reference to FIGS. 7A and 7B. If the optimal deceleration curve is as shown in FIG. As shown in Fig. 7B, the drive voltage applied to the drive voltage is set to a high constant voltage as shown by a straight line p5 in the full speed region, and is applied continuously according to the amount of movement to the target position as shown by a straight line g6 in the control region. The voltage changes as the voltage changes.

This makes it possible to shorten the motor drive time in the control area.

8.9A and 9B are a timing chart and a characteristic diagram of a drive control device showing a second embodiment of the present invention. The major difference between this second embodiment and the first embodiment is that the effective voltage applied to the motor 1 is changed by, for example, 5V in the first embodiment.

Whereas the voltage value was varied such as 3.75V, 2.5V, and 1.25V, in this second embodiment, the voltage value was kept constant, for example, 5V, and the application time was varied.

In Fig. 8, when starting a few pulses before the target position, the drive voltage applied to the motor 1 at the time of starting is temporarily raised to, for example, 5V, as shown by the straight line g7, to improve the start-up of the motor. At the same time, the time tM for temporarily increasing the voltage according to the amount of movement to the target position and its voltage value are stored in the second storage means 7 (see FIG. 1). Then, the driving voltage is temporarily increased for a time t
When M is red, a normal driving voltage, for example 2.5V, is applied to the motor 1 as shown by a straight line I8.

This will be further explained with reference to FIGS. 9A and 9B.

That is, when performing curve control as shown in FIG. 9A, in the full speed range, as shown by the straight line p9 in FIG. 9B, it is the same as in the first embodiment. However, when entering the control area, the 9th B
As shown by straight line '10' in the figure, the target speed is high when starting from a location far from the target position, so by increasing the time tM for temporarily increasing the drive voltage, the target speed can be reached in a short time. Since the target speed will be low if the motor is started from a position close to the target position, the time tM for temporarily increasing the drive voltage is gradually shortened so that the target speed is not exceeded and the startup time of the motor is shortened. The time tM is set as follows.

10A, IOB, and 11 are characteristic diagrams of a drive control device showing a third embodiment of the present invention. In the above 1.2 embodiment, the effective voltage applied to the motor 1, that is, the drive energy, is controlled by changing the voltage value or the application time, whereas in this 3rd embodiment, the rectangular Control is achieved by changing the duty ratio of the wave signal and thereby changing the drive torque. Specifically, such a rectangular wave signal can be realized by repeatedly controlling the motor 1 on and off, or by repeatedly switching the motor drive power source on and off.

When performing curve control as shown in Fig. 10A, the motor is driven at a high duty ratio and therefore a high drive torque in the full speed region as shown by the straight line ρ1□ in Fig. 10B, but once it enters the control region. As shown by the straight line g1□, the duty ratio of the rectangular wave signal is gradually decreased in accordance with the amount of movement to the target position.

Generally, the duty ratio is expressed by the ratio of the on-time Wa to one period Wb of the rectangular wave signal, as shown in FIG. Further, the duty frequency is a reciprocal of the duty ratio and is an element related to the torque of the motor. That is, when the duty frequency is high, the torque decreases, and when the duty frequency is low, the torque increases. Therefore, it is assumed that the second storage means 7 shown in FIG. 1 stores information on the duty ratio and duty ratio number corresponding to the colleague from the target position.

As described in detail in each of the above embodiments, the release time lag can be significantly reduced in driving the AF motor.

Each of the embodiments has been described as an example in which the present invention is applied to an automatic focus adjustment mechanism of a camera, but it goes without saying that the present invention can also be applied to film winding and the like. Furthermore, it goes without saying that the present invention is not limited to cameras and can be widely applied to motor control.

[Effects of the Invention] As described above, according to the present invention, the voltage data corresponding to the amount of movement to the target position, that is, the number of remaining pulses, is stored in the second storage means, and as the target position is approached, the voltage data is stored in the second storage means. ,
Based on this data, the effective voltage applied to the motor is reduced, which has the remarkable effect of shortening the driving time when driving the driven object to the target position and enabling highly accurate control. is demonstrated.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a drive control device according to the present invention, FIG. 2 is a schematic block diagram of an automatic focus adjustment device for a camera, and FIG. 3(A) is a configuration of an encoder in FIG. 2 above. FIG. 3(B) is a timing chart of the PI output signal output from the photointerrupter in FIG. 3(A), and FIG. 4 is a diagram showing the drive of the motor that moves the photographing lens to the target position. Circuit diagram, FIG. 5 is a timing chart 1 of the PI output signal, motor control signal, and motor drive voltage in this first embodiment, and FIG. 6 is a flowchart of lens drive control by the CPU in FIG. 2 above. , Fig. 7A is a characteristic diagram showing the process of curve control of the photographic lens in terms of movement amount and movement speed, and Fig. 7B is a characteristic diagram showing the drive applied to the motor to realize the curve control shown in Fig. 7A above. A voltage characteristic diagram; FIG. 8 is a timing chart of a drive control device showing the second embodiment of the present invention; FIG. 9A is a characteristic line representing the process of curve control of the photographic lens in terms of movement amount and movement speed. In the figure, Fig. 9B is a characteristic diagram showing the time required to temporarily increase the drive voltage applied to the motor to a high voltage in order to realize the curve control shown in Fig. 9A above, and Fig. 10A is a characteristic diagram showing the time when the driving voltage applied to the motor is temporarily increased to a high voltage in order to realize the curve control shown in Fig. 9A above. FIG. 10B is a characteristic diagram showing the process of curve control in terms of movement amount and movement speed.
A characteristic line diagram of the duty ratio of the drive voltage applied to the motor to realize the curve control shown in Fig. 0A, Fig. 11 is a characteristic line diagram explaining the duty ratio shown in Fig. 10B above, Figs. 12A and 12B is a timing chart when starting a conventional drive control device several pulses before the target position. 1...Motor 2...Speed detection means 3...Movement amount calculation means 4 to target position
...... Control means 5 ...... Voltage control means 6 ...... First storage means 7 ...... Number 2 storage means

Claims (2)

[Claims] (1) A motor for driving the driven body to the target position, a speed detection means for detecting the moving speed of the driven body, and a motor for driving the driven body to the target position to stop the driven body at the target position. a first storage means for storing an optimal deceleration curve set according to the amount of movement; a calculation means for detecting the amount of movement of the driven body and calculating the amount of movement to the target position; a control means for controlling the energization state of the motor while comparing the moving speed of the driven body and the deceleration curve based on the movement amount to the target position calculated by the means; and the movement amount to the target position. and a second storage means for storing motor drive voltage data set according to the calculation means, based on the calculated movement amount to the target position and the voltage data stored in the second drive means. A drive control device comprising: , voltage control means for reducing an effective voltage applied to the motor. (2) The voltage control means applies a starting voltage to the motor that is higher than the effective voltage based on the voltage data stored in the second storage means for at least one predetermined period of time when starting the motor. The drive control device according to claim 1, further comprising control means.