JPH0784296A - Shake prevention device - Google Patents

Abstract

PURPOSE:To provide a shake prevention device constituted so that the following-up of a motor is made excellent by accurately driving the motor for preventing shake and the current consumption thereof is reduced. CONSTITUTION:This device is provided with a voltage control circuit 2 for changing a voltage impressed on the motor 3, a duty control circuit 1 controlling the voltage impressed on the motor 3 based on duty ratio, a synthesis means 8 generating a voltage obtained by synthesizing the outputs of the circuits 2 and 1, a speed detection means 4 detecting the rotational speed of the motor 3 driven by the synthesis means 8, an angular velocity sensor 5 detecting the shake, a CPU 6 controlling the control circuits 2 and 1 based on the outputs of the detection means 4 and the sensor 5 and a shake prevention means 7 driven by the motor 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shake prevention device, and more particularly to a control device when a motor is used to drive a shake prevention.

[0002]

2. Description of the Related Art For example, Japanese Unexamined Patent Publication No. 3-122629 discloses an image stabilizing device for preventing image blur caused by camera shake.
In this publication, the servo gain is changed according to the driving position of the correction optical system. That is, the gain is increased near the center of the optical system and decreased at the drive range limit. Further, Japanese Patent Laid-Open No. 3-88881 discloses a motor speed control device by fuzzy control.

[0003]

However, in the above-mentioned Japanese Patent Laid-Open No. 3-122629, correction / control for direct blurring is not performed. In addition, JP-A-3-89
The 881 publication has a drawback in that it takes time to perform the fuzzy control calculation, which causes a time delay and deteriorates the followability.

The shake prevention device of the present invention has been made in view of such a problem, and the purpose thereof is to accurately drive the motor for preventing the shake so as to improve the followability of the motor. And to provide a shake prevention device capable of reducing current consumption.

[0005]

In order to achieve the above-mentioned object, the present invention relates to a shake prevention device for preventing shake by driving a motor, and a voltage for changing the voltage applied to the motor. A control circuit, a duty control circuit that controls the voltage applied to the motor according to the duty ratio, a synthesizing unit that generates a voltage that synthesizes the output of the voltage control circuit and the output of the duty control circuit, and the synthesizing unit. A speed detecting means for detecting a rotation speed of the motor; a shake detecting means for detecting a shake; a control means for controlling the voltage control circuit and the duty control circuit based on outputs of the speed detecting means and the shake detecting means; And a blurring prevention means driven by.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.
In the figure, the voltage control circuit 2 controls to change the voltage applied to the motor 3. The duty control circuit 1 controls the voltage applied to the motor 3 according to the duty ratio. The synthesizing means 8 synthesizes the output of the voltage control circuit 2 and the output of the duty control circuit 1 to generate a voltage. The speed detecting means 4 is a motor 3 driven by the synthesizing means 8.
Detects the rotation speed of. The angular velocity sensor 5 as a shake detecting means detects a shake. The control means (CPU) 6 controls the voltage control circuit 2 and the duty control circuit 1 based on the outputs of the speed detection means 4 and the angular velocity sensor 5. A shake prevention means 7 is connected to the motor 3.

FIG. 3 is a diagram showing the configuration of the second embodiment of the present invention. In FIG. 3, the duty control circuit 1 includes inverters 101, 104, 105, 108, 109, AND gates 102, 103, and NAND gates 106, 1.
07 and the exclusive ORs 110 and 111 input / output signals of “H” and “L”, the transistors 114 and 1
20, 123, 129 are turned on and off.

The voltage control circuit 2 uses the operational amplifier 201 and the transistor 202 based on the output of the digital / analog conversion circuit (D / A) 203 to cause the transistor 2 to operate.
02 terminal voltage on the emitter side is limited. The motor 3 is
It rotates by the current flowing through the collector side of the transistors 116, 117, 126, 127.

The speed detecting means 4 converts the rotating speed of the motor 3 into an electric signal and detects it. The angular velocity sensor 5 as a shake detecting means detects a shake vibration of a device or the like. The CPU 6 performs a predetermined arithmetic processing on the input signal and outputs a control signal. The shake prevention means 7 is a shake prevention means including a correction mechanism such as shaking a lens, and the combining means 8 is composed of a motor bridge circuit of transistors 116, 117, 126, 127.

The duty control circuit 1 receives the "H" and "L" control signals output from the CPU 6, and receives the inverter 1
01, AND gates 102, 103, etc., and transistors 114, 120, 123, 129 are turned ON / OFF via resistors 112, 121, etc., and transistors 116, 117, 12 of the synthesizing means 8 are turned on.
Turn ON / OFF 6, 127.

The voltage control circuit 2 receives an 8-bit signal from the CPU 6 and a digital / analog conversion circuit (D / A) 2
At 03, a voltage corresponding to 8 bits is output. The voltage passes through the operational amplifier 201 and the transistor 202, and the synthesizing means 8
Is supplied to.

The motor 3 rotates by the voltage change limited by the synthesizing means 8. The rotated driving force is transmitted to the shake prevention means 7 and further connected to the speed detection means 4 for detecting the rotation speed. The speed detecting means 4 converts a value corresponding to the speed into a pulse or a voltage and outputs it so that the rotation speed of the motor 3 can be recognized by the CPU 6.

The CPU 6 receives the signals from the angular velocity sensor 5 and the velocity detecting means 4, and raises or lowers the rotation speed of the motor 3.
A control signal is output to the duty control circuit 1 and the voltage control circuit 2 so that control such as maintenance and stop is performed. The synthesizing means 8 is a transistor 116 which is turned on / off by the voltage change of the voltage control circuit 2 and the duty control circuit 1.
The voltage limited by the control of 117, 126, 127 is output to the motor 3.

Next, the case where the CPU 6 receives the outputs of the speed detecting means 4 and the angular velocity sensor 5 and outputs the control signal to the duty control circuit 1 and the voltage control circuit 2 will be described. C
When the PU 6 receives the signal of the angular velocity of camera shake from the angular velocity sensor 5, the PU 6 calculates the drive amount of the motor 3 required by the camera shake prevention unit 7 according to the value of the angular velocity. The value of the drive amount is the value of the rotation speed required for the motor 3, and the conversion is also performed at the same time. The resolution of the converted rotational speed value is 25
If it is set to 6 (8 bits), the CPU 6 outputs "H" and "L" signals at a constant cycle at a ratio corresponding to this resolution.

Specifically, the converted rotational speed value is 32 of the resolution 256, and the time of one cycle is 2
If it is determined to be 56 μsec, “H” is given for 32 μsec.
Is output, and 256-32 = 224 μsec,
"L" is periodically repeated.

Next, further calculation is performed to send the value of the rotation speed to the digital / analog conversion circuit 203 of the voltage control circuit 2. In the voltage control circuit 2, the voltage on the emitter side of the transistor 202 is determined in proportion to the size of the 8-bit data input to the digital / analog conversion circuit 203. Therefore, the CPU 6 increases the output to the digital / analog conversion circuit 203 when the value of the rotation speed of the motor 3 is large, and outputs it so as to decrease when the value is small. Here, it is assumed that four-level output is performed for the value of the rotation speed, and the following calculation is performed.

64 × INT (rotational speed / 64) (1) However, INT represents the meaning of rounding off the value in parentheses.
The result obtained by this calculation is output to the digital / analog conversion circuit 203. In addition to this, the voltage control circuit 2
It is also possible to output the same value as the value output to the duty control circuit 1 without performing the calculation to output the value of the rotation speed.

Now, returning to the control of the CPU 6, the CPU 6 outputs the result obtained by the equation (1) to the digital / analog conversion circuit 203 as 8-bit data. The digital / analog conversion circuit 203 outputs a value from 0v to 5v corresponding to 8 bits. The output voltage is connected to the plus input of the operational amplifier 201, and the output of the operational amplifier 201 is connected to the base of the transistor 202. When the base of the transistor 202 is turned on by the output of the operational amplifier 201, the collector side voltage and the emitter side voltage become equal. On the other hand, operational amplifier 2
Since the negative input of 01 and the emitter side of the transistor 202 are connected, the voltage at the positive input of the operational amplifier 201 and the voltage at the emitter side of the transistor 202 are always limited to be equal. This limited voltage is connected to the emitter side of the transistors 116, 117 of the synthesizing means 8, and the transistors 116, 117, 126, 127 are connected.
Will control the maximum voltage value applied to the motor 3 when is turned ON / OFF.

Next, the CPU 6 also outputs to the duty control circuit 1. To the duty control circuit 1, a PWM signal that outputs a duty ratio, a direction signal that determines the direction in which the motor 3 rotates, and a brake signal are output. The operation of the main circuit performed for these three signals will be described. First, regarding the brake signal, when the brake signal is set to “H” regardless of the direction signal and the duty signal output from the CPU 6, the inverters 108 and 109
And the outputs of the gates of the exclusive ORs 110 and 111 all become "L", and the transistors 123, 126 and 12
Only 7, 129 are turned on, and the motor 3 is short-circuited.

Next, when the brake signal is set to "L", the direction signal is set to "H", and a pulse signal having an appropriate frequency is input as the duty signal, the gate output of the inverter 109 becomes "L", and the transistors 117 and 120. Is OFF
Then, the gate output of the exclusive OR 111 becomes "H", and the transistors 123 and 126 are turned off.

Next, a duty signal is output from the inverters 108 and 109, and in synchronization with this output, the transistors 114, 116, 127 and 129 are turned on / off to pass through the synthesizing means 8 and a voltage is applied to the motor 3. To be done.

Next, detailed operations of the gate and the transistor will be described. The input signal is first the direction signal is "H", the duty signal is an appropriate pulse signal, and the brake signal is "L". When the direction signal “H” and the duty signal are input to the input of the AND gate 102, a duty pulse wave is output.

Next, the NAND gate 106 is supplied with a pulse wave output from the AND gate 102 and a signal in which the brake signal "L" has become "H" through the inverter 104, and an inverted signal of the pulse wave is output. And inverter 1
The inverted pulse wave is input to 08, and the inverter 1
A pulse wave is output from 08.

Further, the exclusive OR 110 receives the inverted pulse wave of the NAND gate 106 and the brake signal "L", and outputs the inverted pulse wave. When the inverted pulse wave output from the exclusive OR 110 is "L", the base of the transistor 129 is turned on, the emitter voltage and the collector voltage become equal, and the base of the transistor 127 is turned on. , The voltage of the emitter and the voltage of the collector become equal.

When the gate output of the exclusive OR 110 is "H", the base of the transistor 129 is OF.
The F state is set, and the base of the transistor 127 is also turned off. Further, when the output of the inverter 108 is "H", the base of the transistor 114 is turned on, and when the emitter is dropped to the ground, the base of the transistor 116 is turned on and the voltages of the emitter and the collector become equal. When the output of the inverter 108 is “L”, the base of the transistor 114 is turned off and the transistor 11 is turned off.
The base of 6 is also turned off.

The AND gate 103 outputs "L" because the direction signal becomes "L" by the inverter 101, and the NAND gate 107 receives the "L" input and the brake "L" signal. However, since it is input as "H" through the inverter 105, "H" is output.
The "H" signal of the NAND gate 107 is input to the inverter 109, and "L" is output. As a result, the transistors 120 and 117 are turned off.

Similarly, to the input of the exclusive OR 111, the output "H" of the NAND gate 107 and the brake signal "L" are input and "H" is output. As a result, the transistors 123 and 126 are turned off.

Next, the operation of the CPU 6 will be described with reference to the schematic flow chart of FIG. First, in step S1,
The angular velocity sensor 5 monitors the angular velocity of camera shake.
In step S2, the rotation speed of the motor 3 currently rotating is monitored. In step S3, the rotational speed of the motor 3 required by the shake prevention means 7 is calculated based on the output of the angular velocity sensor 5, and is compared with the rotational speed of the motor 3 currently rotating.

In step S4, the direction is judged from the output of the angular velocity sensor 5. Here, the direction is discriminated whether it is above or below the reference voltage of the angular velocity sensor 5. In step S5, a duty ratio value corresponding to the speed difference compared in step S3 is determined. In step S6, the maximum value of the applied voltage is determined based on the equation (1). In step S7, the direction signal is output to the duty control circuit 1. Step S
At 8, the voltage control circuit 2 outputs a signal of the applied voltage. In step S9, the duty signal or the brake signal is output to the duty control circuit 1.

In this way, the motor 3 is controlled by the duty control.
Since the maximum voltage applied to the motor 3 can be limited in accordance with the duty ratio when controlling the rotation speed of, the finer control can be performed at low speed rotation, and conversely at high speed rotation. Can be easily controlled without sacrificing accuracy.

Since the control is not performed only by the voltage control circuit, there is a state in which the applied voltage is zero even when the motor is rotating due to the duty ratio control. Therefore, in the state where the camera shake is frequently corrected, there is an advantage that the current consumption can be reduced.

Next, a modified example of the voltage control circuit 2 in FIG. 3 will be described with reference to FIG. The configurations of the digital / analog conversion circuit 203, the CPU 6, and the synthesizing means 8 shown in FIG.

First, the digital / analog conversion circuit 20
A voltage of 0V to 5V is output from 3. Then, the direction signal is output from the CPU 6. When the direction signal is “H”, the inverter 301 outputs the signal “L” and inputs the analog switch 302. In this case, the output of the digital / analog conversion circuit 203 passes through the analog switch 302, is output to the resistor 304 as it is, and enters the negative input of the operational amplifier 306.

When the "H" direction signal is supplied to the other analog switch 303, the output of the digital / analog conversion circuit 203 is cut off and is dropped to the ground by the resistor 307. Next, the signal that has passed through the analog switch 302 enters the negative input of the operational amplifier 306.

Since the resistors 304 and 305 have the same value, the output of the operational amplifier 306 is an inverted output with respect to the input. Next, since the resistors 308, 309, 310, and 311 all have the same value, the output of the operational amplifier 312 becomes equal to the sum of the input of the operational amplifier 306 and the voltage input from the resistor 311. Therefore, the operational amplifier 312 outputs an inverted value of the output of the digital / analog conversion circuit 203. And the power operational amplifier 31 which becomes a buffer
3 and is supplied to the synthesizing means 8.

Next, the case where the direction signal from the CPU 6 is "L" will be described. Contrary to the case described above, the ground level from the operational amplifier 306 and the output level of the digital / analog conversion circuit 203 are directly input to the input of the operational amplifier 312, and are connected to the synthesizing means 8 through the operational amplifier 313. That is, it is possible to control the output voltage of the digital / analog conversion circuit 203 to swing positively or negatively (forward / reverse rotation of the motor) by the direction signal of the CPU 6.

[0037]

As described above, according to the present invention, the motor required for blur correction can be driven with high precision, and therefore control with good followability can be easily realized.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the CPU.

FIG. 3 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a modification of the voltage control circuit shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Duty control circuit, 2 ... Voltage control circuit, 3 ... Motor, 4 ... Speed detection means, 5 ... Angular speed sensor, 6 ... Control means (CPU), 7 ... Blur prevention means, 8 ... Combining means.

Claims (1)

[Claims] 1. A shake prevention device for preventing shake by driving a motor, comprising: a voltage control circuit for changing a voltage applied to the motor; and a duty control circuit for controlling the voltage applied to the motor according to a duty ratio. A synthesizing unit that creates a voltage that synthesizes the output of the voltage control circuit and the output of the duty control circuit; a speed detecting unit that detects the rotational speed of the motor driven by the synthesizing unit; and a shake detecting unit that detects a shake And a shake prevention means driven by a motor, and a shake prevention means driven by a motor. apparatus.