JPH10161005A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stop a motor for focusing with stable accuracy on a stop position by providing a counter performing interruption when an actuator comes within driving stop position accuracy separately from a counter used for ordinary arithmetic calculation. SOLUTION: The 2nd counter 8 monitoring a remaining driving amount to a target position at the time of driving the actuator is provided separately from the counter 7 used for the ordinary arithmetic calculation in the case of controlling the driving of a motor by servo driving. The driving is controlled to be stopped when the interruption is performed based on a counter value and the motor for focusing 5 comes within the desired stop position accuracy. Thus, the motor 5 is surely stopped at the desired position without being influenced by the timing of a control cycle, the control arithmetic calculation time of a microcomputer 2 and the interruption of other control processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel having a built-in actuator such as an electric motor.

[0002]

2. Description of the Related Art As a lens barrel of this type, there is known a lens barrel in which a focusing motor for focusing and driving a focusing lens is provided. An example of a drive control system in the lens barrel 1 with a built-in actuator that incorporates such a focus motor is shown in the block diagram of FIG.

[0005] In FIG. 5, reference numeral 1 denotes a lens barrel. As is widely known, in this lens barrel 1, photographic lens groups constituting a photographic optical system are provided in an appropriate arrangement. A focusing lens 6 for focusing is provided in a part of the lens group so as to be able to advance and retreat in the optical axis direction. Reference numeral 5 denotes a focusing motor (AF motor) for driving the focusing lens 6 for focusing, and the motor 5 performs automatic focusing, that is, so-called auto focusing.

The focus motor 5 is driven and controlled by transmitting an output from a motor control unit 10 in a microcomputer (hereinafter referred to as a microcomputer) 2 provided in the lens barrel 1 through a motor control circuit 3. Is configured. Further, a pulse encoder 4 for detecting a driving state of the focusing motor 5 is provided, and a pulse signal is obtained in proportion to a rotation angle of the driving of the motor 5. That is, a pulse signal is generated from the pulse encoder 4 according to the driving state of the motor 5.

This pulse signal is composed of pulses A and B having a phase shift of 90 degrees.
nA and inB, these pulses A and B
Can be checked by monitoring the relative position of the focusing lens 6, and feedback control of the focusing motor 5 can be performed.

The counter 7 is a quadruple pulse counter, and these counter values are added or subtracted in accordance with the rotation direction of the motor 5 by inputting a pulse signal having a phase difference of 90 degrees. That is, the rotational direction and the rotational displacement of the motor 5 can be confirmed by the counter 7. Therefore, the counter 7 uses the position of the focusing motor 5 based on the position where the pulse encoder 4 is activated.
, That is, the relative position of the focusing lens 6 can be confirmed.

When the operation of driving the focusing motor 5 by a certain drive amount and stopping it (hereinafter referred to as servo driving) using the lens barrel 1 of FIG. The drive control is performed by generating an execution factor for each control cycle and executing a motor control processing task. Then, in the control processing task, the remaining pulses up to the target position are calculated, and if the stop position accuracy is within the desired stop position accuracy, the drive of the motor 5 is stopped.

[0008]

However, when the focus motor 5 which is an actuator provided in the lens barrel 1 is stopped by the above-described drive control, the stop position accuracy is not necessarily within a desired stop position accuracy. There is a problem that the control cycle does not always arrive.

Further, even if the control processing task of the motor 5 can be executed by the control cycle within the stop position accuracy, the timing of the motor stop may be delayed due to the control calculation in the microcomputer 2 or interruption of other control processing. The nature is also high. Further, there is also a problem that the timing of stopping the motor is similarly delayed by disturbance such as uneven load on the controlled side such as the lens 6 and the like, and there is a high possibility that a desired stop position accuracy cannot be obtained. .

The present invention has been made in view of such circumstances, and has a drive controllable lens capable of stopping a focusing motor or the like as an actuator built in a lens barrel with stable stop position accuracy. The purpose is to obtain a lens barrel.

[0011]

In order to meet such an object, a lens barrel according to the present invention comprises a microcomputer for controlling the inside of the lens barrel, an actuator driven and controlled by the microcomputer, and a drive for the actuator. A pulse encoder that generates a pulse in accordance with the above, a counter that monitors the relative drive position of the actuator based on the start of the counter function by reading the drive position of the actuator from the output of the pulse encoder, and uses the counter value. An actuator drive control means for controlling the actuator by a microcomputer, and a second counter different from the counter for monitoring the remaining drive amount up to a target position when the actuator is driven by reading the drive position of the actuator from the output of the pulse encoder. , And interrupt by the counter value Operating by entering it is provided with a actuator stop control means for stopping the driving of the actuator.

Further, the lens barrel according to the present invention is configured such that the microcomputer performs control calculation and control output to drive and control the actuator in a desired control cycle by the actuator drive control means.

According to the present invention, the second counter for monitoring the remaining drive amount up to the target position when the actuator is driven is provided separately from the counter used for ordinary calculations when performing motor drive control by servo drive. By interrupting the actuator based on the count value and stopping the drive when the actuator comes within the desired stop position accuracy, the actuator can be controlled in the timing of the control cycle, the time of the control operation of the microcomputer, and other control processing. The operation can be reliably stopped without being affected by the interruption.

Further, according to the present invention, even if the control becomes unstable due to load unevenness or posture difference on the controlled side, or other disturbance, the above-mentioned reason can be satisfied within the stopping position accuracy of the actuator. , The stop position accuracy can be improved. Further, since the second counter is provided independently of the normal counter, the two counters are not affected by each other, and the position of the focus motor as the actuator as a whole can be managed. In other cases, for example, when speed control must be performed in a mixed manner, the microcomputer can perform arithmetic processing as the same coordinates, and can be treated as a series of flows.

[0015]

FIG. 1 shows an embodiment of a lens barrel according to the present invention. In FIG. 1, the same or corresponding parts as those in FIG. I do. In this embodiment, a second counter 8 for monitoring the remaining drive amount up to a target position when the actuator is driven is provided separately from the counter 7 used for normal calculation or the like when performing motor drive control by servo drive. . Then, an interrupt is inserted according to the count value, and when the focus motor 5 comes within the desired stop position accuracy, the drive of the focus motor 5 is controlled to be stopped.
It is configured to be able to reliably stop at a desired position without being affected by the control cycle timing, the control calculation time of the microcomputer 2, or the interruption of other control processing.

Here, in the pulse signal generated from the pulse encoder 4 in proportion to the rotation angle of the driving of the focusing motor 5, the pulse A and the pulse B which are shifted by 90 degrees in phase.
To the inA and inB of the counter 7 and the second counter 8
Are input to inB and inA. The relative position of the focusing lens 6 can be detected via the motor 5 by counter-monitoring these pulses A and B. Therefore, feedback control of the focus motor 5 becomes possible.

The above-mentioned second counter 8 comprises a counter 7
These are pulse counters for quadruple multiplication. These counter values are added or subtracted in the direction of rotation of the motor 5 by the input of a pulse signal having a phase difference of 90 degrees, so that the direction of rotation can be detected. It has become. Also,
The counter 7 allows the relative angle of the focusing motor 5, that is, the relative position of the focusing lens 6 to be known based on the position where the pulse encoder is activated, and is valid until the power is turned off. The second counter 8
Is a counter for counting the remaining pulses up to the target value when performing the servo drive. In FIG. 1, the pulse A and the pulse B are exchanged by the counter 7 and the second counter 8, which will be described below with reference to a flowchart.

With the above configuration, an algorithm in this embodiment will be described. The focus motor 5
Is performed by generating an execution factor for each control cycle at time t and executing the task of the motor drive control process shown in the flowchart of FIG. The pulse counter 4 used for the calculation of the drive control by the microcomputer 2 and the confirmation of the position of the focus motor 5 is mainly used by the counter 7, and unless otherwise specified in the following description, the pulse counter 4 is used. The counter value of 7 is used.

First, when an arbitrary servo drive is performed, in step 1 (S1), if the control process is not the first control process of the servo drive, the process jumps to S6. , And a target position is determined in S3. Then, the driving direction of the motor 5 is determined in S4.

In the next step S5, control processing for the second counter 8, which is a feature of the present invention, is performed. More specifically, in S6, a remaining pulse calculation indicating the number of pulses to the target position is performed, and in S7, it is determined whether the remaining pulse is within the stop accuracy. Then, if the stop accuracy is within the stop accuracy, the servo drive is terminated in S9.
In the motor drive control process in step 8, the microcomputer 2 performs control calculation and control output, returns, and thereafter repeats the above steps. That is, in the next control cycle, the process is repeated through S1 to S6.

FIG. 4 shows the details of the start processing of the remaining pulse counter 8 in S5. To explain this,
This subroutine is for improving the stop accuracy at the time of servo drive. The remaining pulse, which is the drive amount, is input to the second counter 8 before the start of servo drive, and the second pulse when the stop position accuracy is reached is obtained. Processing is performed to determine whether or not to interrupt based on whether or not the count value of the second counter 8 overflows or underflows.

In FIG. 4, the direction in which the motor 5 is to be driven is determined in S10, and if the pulse of the counter 7 is decreasing, this S10 is performed, and the stop accuracy is set to the target position in consideration of the margin of stop accuracy. Buffer the added value (B
UF1), and if the pulse of the counter 7 is increasing, the process proceeds to S12, and a value obtained by subtracting the stop accuracy from the target position is stored in the buffer (BUF1). When the pulse has decreased, the process proceeds to S11, and a value obtained by adding the target position and the stop accuracy is stored in the buffer (BUF1).

In any case, the interrupt is disabled in S13, and the difference between the value of the buffer (BUF1) and the value of the counter 7 is input to the second counter 8 in S14.
In step 5, the second counter 8 is started, the interruption is permitted in step S16, and the process returns to the main routine of FIG.

The interrupt processing when the servo drive enters the stop accuracy and the interruption of the second counter 8 occurs will be described with reference to the flowchart of FIG. That is, the second counter 8 is stopped in S17, the focus motor 5 is forcibly stopped in S18, and then the process returns to the main routine. Since the routines in these flowcharts are intended to stop the focus motor 5, only the stop control of the motor 5 is performed, and the post-processing of the servo drive is performed by the motor drive control processing in the next control cycle.

The present invention is not limited to the structure described in the above embodiment, and it goes without saying that the shape and structure of each part can be appropriately modified and changed. For example, various modifications can be considered for the specific configuration of the lens barrel 1, the actuator such as the focusing motor 5 for driving the focusing lens 6, and the configuration of other control systems.

[0026]

As described above, according to the lens barrel according to the present invention, when the motor drive control is performed by the servo drive, the actuator has the drive stop position accuracy within the accuracy of the drive stop position. The provision of the second counter for interrupting at the time of entry causes the following excellent effects.

According to the present invention, the driving of the actuator (motor) can be reliably stopped without being affected by the timing of the control cycle, the processing time of the control operation in the microcomputer, or other interrupt processing.

Further, according to the present invention, even when the control becomes unstable due to load unevenness, a posture difference, other disturbance, or the like in the controlled system, the actuator is reliably stopped within a desired stop position accuracy. The stop position accuracy can be improved. Further, since the second counter is provided independently, the position of the entire actuator managed by the counter for normal servo drive can be managed without being affected by the second counter. Becomes In addition, even when the speed control must be performed in a mixed manner, for example, in addition to the servo drive, the microcomputer can calculate the same coordinates and can handle the same as a series of flows.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a lens barrel according to the present invention.

FIG. 2 is a flowchart illustrating one embodiment of the lens barrel according to the present invention and illustrating a main routine in the lens barrel.

FIG. 3 is a flowchart for explaining a start process of a second counter for remaining pulses in FIG. 2;

FIG. 4 is a flowchart illustrating an interrupt process when the count value of a second counter is under or over.

FIG. 5 is a block diagram showing an example of a conventional lens barrel corresponding to FIG.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 lens barrel 2 microcomputer (microcomputer) 3 motor drive circuit 4 pulse encoder 5
... Focus motor (actuator), 6 Focus lens, 7 Counter, 8 Second counter, 9
... Motor stop unit, 10 ... Motor control unit.

Claims (2)

[Claims] A microcomputer that controls the inside of a lens barrel; an actuator that is driven and controlled by the microcomputer; a pulse encoder that generates a pulse in accordance with driving of the actuator; A counter that monitors the relative drive position of the actuator based on the start of the counter function by reading from the output of the pulse encoder; and an actuator drive control that controls the actuator by the microcomputer using the counter value of the counter. Means for reading a drive position of the actuator from an output of the pulse encoder to monitor a remaining drive amount up to a target position when the actuator is driven. Kicking with the lens barrel, characterized in that said operating by interrupt occurs by the second counter value of the counter is provided an actuator stop control means for stopping the driving of the actuator. 2. The lens barrel according to claim 1, wherein the microcomputer performs a control operation and a control output to drive and control the actuator in a desired control cycle by the actuator drive control means. Lens barrel.