ACTUATOR CONTROL APPARATUS

• US 20140207287A1
• Filed: 01/22/2013
• Published: 07/24/2014
• Est. Priority Date: 01/22/2013
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Inventors: Hirayama, Hideki
• Granted Patent: US 9,519,277 B2
• Time in Patent Office: Days
• US Class Current: 700/275
• CPC Class Codes: G05B 19/042 using digital processors G05B19/05 takes precedence

Abstract

An actuator control apparatus includes an analog-digital conversion circuit, a servo circuit, a sampling circuit, and a driving circuit. The analog-digital conversion circuit is configured to sample a position detection signal with a first sampling period, convert the sampled signal into a digital signal, and output the digital signal, the position detection signal outputted from a position sensor corresponding to a position of a control target. The servo circuit is configured to calculate a displacement amount, by which the control target is to be displaced by an actuator, and output first servo control data corresponding to the calculated displacement amount, based on the position detection signal converted into the digital signal. The sampling circuit is configured to linearly interpolate the first servo control data, and output second servo control data sampled with a second sampling period shorter than the first sampling period.

Claims

1. An actuator control apparatus comprising:

an analog-digital conversion circuit configured to sample a position detection signal with a first sampling period, convert the sampled signal into a digital signal, and output the digital signal, the position detection signal outputted from a position sensor corresponding to a position of a control target;

a servo circuit configured to calculate a displacement amount, by which the control target is to be displaced by an actuator, and output first servo control data corresponding to the calculated displacement amount, based on the position detection signal converted into the digital signal;

a sampling circuit configured to linearly interpolate the first servo control data, and output second servo control data sampled with a second sampling period shorter than the first sampling period; and

a driving circuit configured to drive the actuator in accordance with the second servo control data.

2. The actuator control apparatus according to claim 1, wherein

the second sampling period is ½

times as long as the first sampling period; and

the sampling circuit is further configured to output, as the second servo control data, the first servo control data and an average value of two contiguous pieces of data of the first servo control data in an alternate manner every second sampling period.

3. The actuator control apparatus according to claim 2, wherein

the sampling circuit includes

a selection circuit configured to select and output the first servo control data and a value of 0 in an alternate manner every second sampling period,

a first delay device configured to delay an output value of the selection circuit by the second sampling period,

a second delay device configured to delay an output value of the first delay device by the second sampling period, and

an adder configured to add a value obtained by multiplying an output value of the selection circuit by 0.5, an output value of the first delay device, and a value obtained by multiplying an output value of the second delay device by 0.5, and output a result as the second servo control data.

4. The actuator control apparatus according to claim 2, wherein

the sampling circuit includes

a first delay device configured to delay the first servo control data by the second sampling period,

a first multiplier configured to multiply the first servo control data by a first coefficient,

a second multiplier configured to multiply an output value of the first delay device by a second coefficient, and

an adder configured to add an output value of the first multiplier and an output value of the second multiplier, and output a result as the second servo control data, and wherein

the first coefficient is switched in an alternate manner between 0 and 0.5 every second sampling period, and

the second coefficient is 1 when the first coefficient is 0, and is 0.5 when the first coefficient is 0.5.

5. The actuator control apparatus according to claim 2, wherein

the sampling circuit includes

a first delay device configured to delay the first servo control data by the second sampling period, and

an adder configured to add a value obtained by multiplying the first servo control data by 0.5, and a value obtained by multiplying an output value of the first delay device by 0.5, and output a result as the second servo control data.

6. The actuator control apparatus according to claim 1, wherein

the control target is a diaphragm mechanism of an image pickup device, and

the position sensor is a hall sensor.

7. The actuator control apparatus according to claim 2, wherein

the control target is a diaphragm mechanism of an image pickup device, and

the position sensor is a hall sensor.

8. The actuator control apparatus according to claim 3, wherein

the control target is a diaphragm mechanism of an image pickup device, and

the position sensor is a hall sensor.

9. The actuator control apparatus according to claim 4, wherein

the control target is a diaphragm mechanism of an image pickup device, and

the position sensor is a hall sensor.

10. The actuator control apparatus according to claim 5, wherein

the control target is a diaphragm mechanism of an image pickup device, and

the position sensor is a hall sensor.

11. An image pickup device comprising:

a position sensor configured to output a position detection signal, which is an analog signal, corresponding to a position of diaphragm blades;

an analog-digital conversion circuit configured to sample the position detection signal with a first sampling period, convert the sampled signal into a digital signal, and output the digital signal;

a servo circuit configured to calculate a displacement amount, by which the diaphragm blades are to be displaced by an actuator, and output first servo control data corresponding to the calculated displacement amount, based on the position detection signal converted into the digital signal;

a sampling circuit configured to linearly interpolate the first servo control data, and output second servo control data sampled with a second sampling period shorter than the first sampling period; and

a driving circuit configured to drive the actuator in accordance with the second servo control data.

12. The image pickup device according to claim 11, wherein

the second sampling period is ½

times as long as the first sampling period; and

the sampling circuit is further configured to output, as the second servo control data, the first servo control data and an average value of two contiguous pieces of data of the first servo control data in an alternate manner every second sampling period.

13. The image pickup device according to claim 12, wherein

the sampling circuit includes

a selection circuit configured to select and output the first servo control data and a value of 0 in an alternate manner every second sampling period,

a first delay device configured to delay an output value of the selection circuit by the second sampling period,

a second delay device configured to delay an output value of the first delay device by the second sampling period, and

an adder configured to add a value obtained by multiplying an output value of the selection circuit by 0.5, an output value of the first delay device, and a value obtained by multiplying an output value of the second delay device by 0.5, and output a result as the second servo control data.

14. The image pickup device according to claim 12, wherein

the sampling circuit includes

a first delay device configured to delay the first servo control data by the second sampling period,

a first multiplier configured to multiply the first servo control data by a first coefficient,

a second multiplier configured to multiply an output value of the first delay device by a second coefficient, and

an adder configured to add an output value of the first multiplier and an output value of the second multiplier, and output a result as the second servo control data, and wherein

the first coefficient is switched in an alternate manner between 0 and 0.5 every second sampling period, and

the second coefficient is 1 when the first coefficient is 0, and is 0.5 when the first coefficient is 0.5.

15. The image pickup device according to claim 12, wherein

the sampling circuit includes

a first delay device configured to delay the first servo control data by the second sampling period, and

an adder configured to add a value obtained by multiplying the first servo control data by 0.5, and a value obtained by multiplying an output value of the first delay device by 0.5, and output a result as the second servo control data.

16. A method for controlling a diaphragm of an image pickup device, comprising:

detecting a position of diaphragm blades;

generating a position detection signal which is an analog signal;

converting the position detection signal sampled with a first sampling period into a digital signal;

calculating a displacement amount, by which the diaphragm blades are to be displaced by an actuator, based on the position detection signal converted into the digital signal;

generating first servo control data corresponding to the calculated displacement amount;

generating second servo control data sampled with a second sampling period shorter than the first sampling period, with the first servo control data being linearly interpolated; and

driving the actuator in accordance with the second servo control data.

17. The method for controlling the diaphragm according to claim 16, further comprising:

generating the second servo control data by selecting the first servo control data and an average value of two contiguous pieces of data of the first servo control data in an alternate manner every second sampling period, wherein

the second sampling period is ½

times as long as the first sampling period.

18. The method for controlling the diaphragm according to claim 17, further comprising:

generating selection data by selecting the first servo control data and a value of 0 in an alternate manner, every second sampling period;

generating first delay data obtained by delaying the selection data by the second sampling period;

generating second delay data by delaying the first delay data by the second sampling period; and

generating the second servo control data by adding a value obtained by multiplying the selection data by 0.5, the first delay data, and a value obtained by multiplying the second delay data by 0.5.

19. The method for controlling the diaphragm according to claim 17, further comprising:

generating first delay data by delaying the first servo control data by the second sampling period;

calculating a first multiplication value by multiplying the first servo control data by a first coefficient;

calculating a second multiplication value by multiplying the first delay data by a second coefficient; and

generating the second servo control data by adding the first multiplication value and the second multiplication value, wherein

the first coefficient is switched in an alternate manner between 0 and 0.5 every second sampling period, and

the second coefficient is 1 when the first coefficient is 0, and is 0.5 when the first coefficient is 0.5.

20. The method for controlling the diaphragm according to claim 17, further comprising:

generating a first delay data by delaying the first servo control data by the second sampling period, and

generating the second servo control data by adding a value obtained by multiplying the first servo control data by 0.5, and a value obtained by multiplying the first delay data by 0.5.