JP3328421B2 - Servo circuit for driving TV camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control contents and a configuration of a servo circuit used for controlling a television camera and a camera platform, for example.

[0002]

2. Description of the Related Art In various fields, a servo circuit for controlling a mechanical position of a drive system is used. This servo circuit is also applied to, for example, a pan head for moving a television camera or a lens. I have. That is, in the camera platform supporting the television camera, pan (left and right directions) and tilt (up and down directions) are performed by a servo circuit, and a zoom lens and a focus lens in the television camera are driven by the servo circuit.

[0003]

However, in the conventional servo circuit, the movement of the driving object becomes unnatural or the operation of the driving object becomes unnatural due to the backlash of the gear disposed in the driving system from the motor to the driving object. There was a problem that the movement was not as expected. FIG. 6 shows a pan head control operation by a conventional servo circuit. This is an example of a case where the direction is changed from the position P1 to the position P2 in the pan operation of the television camera, for example. In this case, as shown in FIG. 7A, the position control signal is a position signal voltage proportional to the distance from the position P1 to the position P2, and the motor is driven by this position signal voltage. At this time, the trajectory of the television camera, which is the object to be driven, suddenly changes after the time t1 has elapsed since the start of the control due to the existence of the backlash, as shown by the curve 100 (time t2) in FIG. It starts moving (time t3 is normal operation).

[0004] This is because the television camera does not actually move when the backlash B of the gear shown in the motor locus in FIG. As described above, the rotational speed of the motor rapidly increases during the time t1. That is, in the position control of the servo circuit, the motor is driven and controlled by the position signal voltage proportional to the distance from the current position to the target position. However, if the backlash exists, the current position does not change. Increases, and the rotation speed of the motor rapidly increases. For this reason, the camera platform and the like are driven at a large number of revolutions, and as a result, the movement of the television camera becomes sharp, and the movement of the television camera becomes unnatural.
In addition, a load is applied to the drive system.

Next, as shown in FIG. 7, the television camera is panned and tilted to move from position P3 to position P.
Suppose you move to 4. Here, if the direction is changed only for the pan and the pan is moved to the right side, while the backlash of the pan is being driven, the camera moves upward in the tilt, so that the television camera does not proceed straight from the position P3 to the position P4. The trajectory 200 will be followed. Therefore, in this case, there is a disadvantage that the camera cannot accurately follow the subject.

Therefore, conventionally, an attempt has been made to reduce the backlash by minimizing the meshing of the gears and the like, but it is impossible to reduce the backlash to zero. In addition, there is a problem in that the gear meshing becomes deeper, which causes a reduction in gear efficiency and uneven operation due to mismatching of the gear meshing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to eliminate unnatural movements caused by backlash of gears arranged in a drive system of a television camera. When operating the drive systems simultaneously, a TV camera that can drive accurately as
An object of the present invention is to provide a camera driving servo circuit.

[0008]

In order to achieve the above object, the invention according to the first aspect is used for driving a television camera and a lens, and detects a position of a detected drive system and a target position. In a television camera driving servo circuit that drives and controls a motor based on a position control signal corresponding to the distance, a time for driving a backlash generated by a gear disposed in the driving system is set, and in this backlash driving time, Speed controlling the motor without providing the position control signal, stopping the speed control when the backlash drive time has elapsed, and driving the motor by providing the position control signal. . The backlash drive time is a time within the actual backlash drive time. According to a second aspect of the present invention, when the drive system is operated by the manual operation means, an operation area for driving the backlash is provided, and the speed control is performed during the operation time of the backlash operation area. Features. The invention described in claim 3 is
When simultaneously controlling a plurality of drive systems, the difference in the backlash drive time is taken into account, and the substantial drive start times of the respective drive systems after the backlash drive are matched. .

[0009]

According to the above configuration, when driving the backlash, the speed is controlled to a constant speed for a predetermined time without setting the position control signal. Therefore, unlike the case of the position control, the motor rotation speed does not suddenly increase, and the gear is rotated at a constant motor rotation speed. Then, after driving the backlash is, above
Since the speed control described above is stopped and the control returns to the position control based on the position control signal, the driven object is moved by the stable motor rotation speed. When using an operation member such as a joystick, it is preferable to provide a backlash operation area in a part of the operation area where the operation lever is tilted,
In this case, the operation time of the operation lever passing through the backlash operation area is adjusted to the predetermined time. According to this, the backlash operation area can be set as a dead zone area, and by controlling the speed for the time required to pass through the dead zone, it becomes possible to drive the backlash. In addition, an operation feeling consistent with the actual driving can be obtained.

When two driving systems, for example, a pan and tilt driving system of a television camera are driven at the same time, after the backlash is driven, the start times of the actual operations of the pan and tilt are matched. Since the TV camera is controlled, the TV camera can be moved along the trajectory according to the operation without either one of the operations being delayed or accelerated.

[0011]

FIG. 1 shows a configuration of a servo circuit for driving a television camera according to an embodiment. This embodiment is an example applied to a television camera and a camera platform. In FIG. 1, a plurality of operation switches 10 and a plurality of indicator lamps 11 (only one is shown in FIG. 1) are arranged on the operation section of the camera platform. A shot switch for moving the camera is provided. Further, a joystick 12 for driving the camera to an arbitrary position by a manual operation is provided. The operation signal of the operation switch 10 is directly supplied to an input / output (I / O) unit 14 and the joystick 1
2 is input / output (I / O) through the A / D converter 15.
/ O) section 14. Then, an operation control signal of the joystick 12 and an operation control signal from the CPU 22 described later are supplied to the servo amplifier 17 via the D / A converter 16.

The servo amplifier 17 includes a motor corresponding to each drive system for performing a pan (left-right direction) operation, a tilt (up-down direction) operation, a focus operation of a lens in a camera unit, and a zoom operation of a television camera. 18 and the position detector 19 are connected to each other.
And each driven object are connected by a plurality of gears. Therefore, the backlash slightly differs depending on each drive system. The output of the position detector 19 is supplied to the A / D converter 20 and the I / O unit 14.
Is supplied to a CPU 22 to be described later.

A CPU 22 for controlling various controls is provided, and a memory (RAM) 23 for storing shot position information and a current driving direction, and a memory (ROM) 24 for storing a control program are provided. RAM 23
The shot position information stored in the operation switch 1
0 when the shot switch is pressed, and a control signal based on this is sent from the CPU 22 to the servo amplifier 1.
7 given. The ROM 24 stores a drive time t1 for the backlash of each drive system, and the drive time t1 is configured to be selectable from a plurality of values.

The CPU 22 compares the current (previous) drive direction stored in the RAM 23 with the operation direction and performs control to drive the backlash when reverse drive is performed. Therefore, in the case of this inversion drive, the backlash drive time t1 of each drive system stored in the ROM 24 is given to the servo amplifier 17 via the I / O unit 14. Then, a setting signal for position control is also supplied to the servo amplifier 17 via the I / O unit 14. The backlash drive time t1 can be automatically set by the CPU 22 calculating based on a change in the motor current value and the like detected during the actual drive. The backlash drive time t1 is an optimum time according to the operation speed and the speed control output (speed) within the backlash drive time t1 is determined by the CPU 22.
And the backlash drive time t1 and the speed control output may be set to change automatically and continuously.

Further, the CPU 22 of the embodiment controls so that substantial driving of each drive system is performed simultaneously in consideration of backlash of the four drive systems. That is, the amount of backlash is slightly different in each of the pan, tilt, focus, and zoom drive systems, and when these are simultaneously driven in reverse, a movement shift occurs between them. In some cases, one is driven in the same direction as the previous time, and the other is driven in the opposite direction. Therefore, in the embodiment, after the driving of the inverting driving system or the driving system having the longest backlash driving time t1 in this driving system is completed, the substantial driving of all the driving systems is simultaneously performed. Start control is performed. As a result, driving can be performed on the locus as operated.

FIG. 2 shows an operation area of the joystick. As shown in FIG.
Numeral 6 can be tilted from the vertical position to the position Q1 or Q2 in all directions. And D is a dead zone area,
E is set as a backlash operation area, and F is set as an actual operation area. The backlash operation area E is:
Since it is not related to the substantial driving, it can be called the second dead zone. However, by providing such a backlash operating region of the dead zone, the actual operation of the joystick coincided with the actual driving. There is an advantage that an operation feeling can be obtained.

The embodiment has the above configuration, and its operation will be described with reference to FIGS. In a television camera, a shot operation for moving to a preset position and a manual operation using a joystick are performed. In this shot operation, when a predetermined operation switch 10 is operated, CP
U22 reads the position information stored in the RAM 23,
By supplying the position control signal to the servo amplifier 17, the drive to the corresponding position is executed. Then, in the comparison between the shot position information and the current position, if there is a drive system to be inverted, a speed control setting signal and a position control setting signal for performing speed control are supplied to the servo amplifier 17. .

FIG. 3 shows a driving system for inverting driving at a position P1.
The control state in the case where the driving target is moved from the position P2 to the position P2 is shown. As shown in FIG. 3A, the control signal of the speed control voltage V1 is transmitted to the motor 18 during the backlash driving time t1. And the position control signal shown in FIG. As a result, the backlash B shown in FIG. (D) is driven, but the motor rotation speed becomes constant as shown in FIG. Then, after the backlash drive time t1, a position control signal of the position signal voltage Vp shown in FIG. 3B is given, whereby the driven object is driven from the position P1 to the position P2. In this way, the motor 18 of the embodiment always maintains a stable rotation speed as shown in FIG. Therefore, abrupt movement of the driving object in the pan, tilt, zoom, and focus operations is prevented, and natural driving is achieved.

FIG. 4 shows the operation of the CPU when the joystick of FIG. 2 is used. First, when the operation amount of the operation lever 26 is input to the CPU 22 in step 101, it is determined in step 102 whether the operation amount is in the dead zone D. And Y (Yes)
, The backlash flag (B
F) is reset to 0, and if N (No), step 10 is executed.
Then, it is determined whether the operation amount of the operation lever 26 is in the backlash operation area E or not (step 4). If Y in step 104, that is, if the operation lever 26 is operated in the backlash operation area E, the process proceeds to step 105 to determine whether the current operation direction matches the previous drive direction. I do. That is, it is determined here whether the motor 18 is to be reversed or to be rotated in the same direction.

If it is determined in step 105 that the operation direction matches the previous drive direction (when Y), the current control operation is terminated, but the operation direction matches the previous drive direction. Inverting operation (N)
Determines in step 106 whether or not BF is 1. That is, if the backlash is already being driven, this BF becomes 1, so it is determined whether or not the backlash is being driven by this operation. When it is determined in step 106 that the backlash flag is not 1 (N), the speed control voltage V1 of FIG. 3A is output to the servo amplifier 17 in the next step 107. Here, the driving for the backlash in the operation time corresponding to the time t1 in FIG.
This is executed by the motor 18 having a predetermined rotation speed. When the driving for this backlash is completed, the process proceeds to the next step 108, where BF is set to 1 and the control operation is completed.

If the answer is N in step 104, that is, if the operation lever 26 is in the substantial operation area F, the position signal voltage Vp is output to the servo amplifier 17 in step 109, and the normal operation is performed. Position control is performed, and in step 110, the driving direction of the motor 18 is stored in the RAM 23, and the operation is terminated. Accordingly, here, the time t in FIG.
4, the pan, tilt, zoom, and focus drive systems are driven in accordance with the operation amount of the operation lever 26.

FIG. 5 shows the operation at the start when the respective driving systems are simultaneously driven. That is, bread
The drive system and the tilt are assumed to be a B drive system. For example, in the A drive system, the backlash drive time t1A shown in FIG. 5A is set, and in the B drive system, the backlash drive time t1B shown in FIG. Are set, and both are driven to be inverted. In this case, even if the driving of the B driving system for the backlash driving time t1B ends, the next position control is not immediately performed, and the time when the backlash driving time t1A of the A driving system ends is set as a start time Tp. The next position control is started in both drive systems A and B. Accordingly, in this case, there is no delay in either panning or tilting operation. In the conventional FIG. 7, the television camera moves straight from the position P3 to the position P4 without passing through the trajectory 200, and Movement can be achieved.

FIG. 5C shows a case where the B drive system is driven in the same direction. In this case, the backlash drive time t1B becomes zero. Also in this case, the operation of the B driving system is suspended until the driving for the backlash of the A driving system is completed, and the next position control of both the A and B driving systems is started from the start time Tp. This simultaneous start control is executed between the four drive systems, and is particularly important in the relationship between pan and tilt, the relationship between pan and tilt, and the relationship between focus and zoom.

In the above embodiment, the control of the television camera and the camera platform has been described. However, the present invention is not limited to these controls, and the present invention can be applied to a servo circuit for controlling the position of various devices. Also, an example in which a joystick is used as the manual operation means has been described, but the present invention is not limited to this, and another operation means such as a trackball can be used as the manual operation means.

[0025]

As described above, according to the first aspect of the present invention, in the television camera driving servo circuit, the time for driving the backlash generated by the gears arranged in the driving system is set, and this time is set. In the backlash drive time, the motor is driven only by speed control , and when the backlash drive time elapses, the motor is driven by applying only the position control signal, so the motor is stable even if gear backlash exists. It is possible to drive at the set rotation speed, and it is possible to eliminate unnatural movement of the driven object.

According to the second aspect of the invention, when a manual operation means such as a joystick is used, an operation area for driving the backlash is provided, and the speed is controlled during the operation time of the backlash operation area. Therefore, there is an advantage that the driving for the backlash can be performed in the dead zone region, and in a substantial driving operation, an operation feeling consistent with the actual driving can be obtained.

According to the third aspect of the present invention, when a plurality of drive systems are simultaneously controlled, the actual drive start times of the respective drive systems after the backlash drive are made to coincide with each other. It is possible to drive the street exactly.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a television camera driving servo circuit according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation area of a joystick according to the embodiment.

FIG. 3 is a waveform chart showing a control operation of the embodiment.

FIG. 4 is a flowchart illustrating a control operation by the joystick according to the embodiment.

FIG. 5 is a waveform chart showing a control operation of two driving systems in the embodiment.

FIG. 6 is a waveform diagram showing a control operation in a conventional servo circuit.

FIG. 7 is a diagram showing a trajectory of a driving target when two driving systems are operated in the related art.

[Explanation of symbols]

 10 ... operation switch, 12 ... joystick, 17 ... servo amplifier, 18 ... motor, 19 ... position detector, 22 ... CPU, t1 ... backlash drive time.

Continuation of the front page (56) References JP-A-60-116004 (JP, A) JP-A-5-19156 (JP, A) JP-A-5-110923 (JP, A) JP-B-52-18356 (JP, A) , B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) G05D 3/00-3/20 G05B 19 / 18,19 / 404 H04N 5/222

Claims (3)

(57) [Claims] 1. A television camera driving servo circuit which is used to drive a television camera and a lens, and drives and controls a motor based on a position control signal corresponding to a distance between a detected position of a driving system and a target position. In the above, a time for driving the backlash generated by the gears arranged in the drive system is set, and in the backlash drive time, the speed of the motor is controlled without giving the position control signal. The above speed at the time
A television camera driving servo circuit for driving the motor by stopping the control and applying the position control signal. 2. When the drive system is operated by manual operation means, an operation area for driving a backlash is provided, and the speed control is performed during an operation time of the backlash operation area. The servo circuit for driving a television camera according to claim 1. 3. When simultaneously controlling a plurality of drive systems, the difference in the backlash drive time is taken into account, and the substantial drive start times of the respective drive systems after the drive for the backlash are matched. 2. The servo circuit for driving a television camera according to claim 1, wherein: