JP3328422B2 - 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 thereof, and detects a position of a detected drive system and a target position. Whether the position control signal corresponding to the distance of
In the television camera drive servo circuit that drives and controls the motor by applying the same, the time required to completely drive the backlash generated by the gears arranged in the drive system is equal to or shorter than the time required for the backlash drive setting time. In the backlash drive set time, the position control signal is applied from 0 to control the drive to drive the backlash, and when the backlash drive set time elapses, the position control signal is set to 0. characterized in that so as to start a new position control back. In the above, the backlash drive set time does not mean only the time for actually driving the backlash part completely, but is a time within the actual drive time,
It is preferable to set the time slightly shorter than the time for completely driving. 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 when the operation time of the backlash operation area elapses, the position control signal is output at the time of starting the drive. , And the position control is newly started. According to the third aspect of the present invention, when a plurality of drive systems are controlled simultaneously, the difference between the backlash drive times is taken into account, and the substantial drive start times of the respective drive systems after the backlash drive are matched. It is characterized in that it is made to be.

[0009]

According to the above arrangement, after the backlash is almost driven by the position control, the position control signal is returned to the original (initial) state, and a new position control is started. Therefore, a sudden change in the motor rotation speed as in the related art is reduced, and the gear is rotated at a stable motor rotation speed. When an operating member such as a joystick is used, it is preferable to provide a backlash operating area in a part of the operating area where the operating lever is tilted. In this case, the time required for the operating lever to pass through the backlash operating area is equal to the backlash operating time. It will be adjusted to the drive set time. According to this, the backlash operation area can be set as a dead zone area, and an operation feeling consistent with 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, the start time of the actual operation of the pan and tilt is set after the backlash driving set time has elapsed. Since the control is performed so as to coincide with each other, the television 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 backlash drive set time t4 of each drive system, and the drive set time t4 is configured to be selectable from a plurality of values. In the embodiment, as described later, the time t4 is set to a time shorter than the time t1 (FIG. 6) for completely driving the actual backlash, thereby controlling the motor rotation speed so as not to become too large. Is done.

The CPU 22 compares the current 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, after the lapse of the backlash drive set time t4 of each drive system,
A position control setting signal for starting a new position control is I
The signal is supplied to the servo amplifier 17 via the / O section 14. The backlash drive set time t4 can be automatically set by the CPU 22 calculating based on a change in the motor current value or the like detected during the actual drive.

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. Also, one is a forward drive,
The other may be driven in reverse, and in this case as well, there is a shift between the movements. Therefore, in the embodiment, after the drive for the backlash of the drive system that performs the inversion drive or the drive system having the longest backlash drive set time t4 of this drive system is completed, the substantial drive of all the drive systems is performed. Start control is performed at the same time. 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. In the comparison between the shot position information and the current position, if there is a drive system that is to be inverted, the position control setting signal for returning the position control signal to the original value after the set time t4 is transmitted to the servo amplifier 17. Supplied to

FIG. 3 shows a driving system for inverting driving at a position P1.
The control state in the case where the object to be driven is moved from the position P2 to the position P2 is shown. As shown in FIG. 3A, first, the position signal voltage Vp is applied to the motor 18 during the backlash drive set time t4. Can be This drives the backlash B shown in FIG. As shown in the figure, a time t1 is required to completely drive the backlash B, but at a time t4 slightly before this, as shown in FIG.
The position signal voltage Vp is returned to the original value, that is, 0, and a new position signal voltage Vp is output. Therefore, the object to be driven is driven from the position P1 to the position P2 by the new position signal voltage Vp. The motor 18 at this time
(D), the number of revolutions increases at first, but decreases after time t4, and the time when the backlash B is driven to start the actual driving (time t1)
After), the rotation speed becomes stable. Therefore, abrupt movement of the drive target in pan, tilt, zoom, and focus operations is prevented, and driving with a natural movement is realized.

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 forward.

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 (in the case of N), in the next step 107, the first position signal voltage Vp in FIG. The drive for the backlash during the set time t4 is executed by the motor 18,
Move to the next step 108.

In step 108, it is determined again whether or not the operation lever 26 is in the backlash operation area E. When the result is N, that is, when the driving of the backlash is almost finished, in step 109, the position is determined. Signal voltage Vp
Is returned to 0, and the new position signal voltage Vp is
7, and then the BF is set to 1. Therefore, at this point, the motor drive for the set backlash drive time set by the operation time of the backlash operation area E ends.

If 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 110 to control the position. And step 111
Then, the driving direction of the motor 18 is stored in the RAM 23,
End the operation. Accordingly, in this case, stable driving at time t5 in FIG. 3 is performed, whereby each of the pan, tilt, zoom, and focus driving systems is 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, a backlash drive set time t4A shown in FIG. 5A is set for the A drive system, and a backlash drive set time shown in FIG. 5B is set for the B drive system. It is assumed that t4B has been set and both are driven to invert. In this case, even if the driving of the B drive system for the backlash drive set time t4B ends, the next new position control is not immediately performed, and the operation starts when the backlash drive set time t4A of the A drive system ends. At time Tp, new 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 to rotate in the normal direction. In this case, the set backlash drive time t4B 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 new 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.

[0026]

As described above, according to the first aspect of the present invention, in the servo circuit for driving the television camera, the time required to completely drive the backlash generated by the gears arranged in the drive system is equal to or less than the time. A shorter time is set as the backlash drive set time, and the backlash drive set time is used to drive the backlash by the position control signal given from 0. When the backlash drive set time elapses, the position Since the control signal is returned to 0 and a new position control is started, even if there is a gear backlash, a rapid increase in the number of revolutions of the motor is prevented, and unnatural movement of the driven object is eliminated. It becomes possible.

According to the second aspect of the present invention, when manual operation means such as a joystick is used, an operation area for driving the backlash is provided, and a position signal is obtained based on the operation time of the backlash operation area. Since the position control is started again by returning to the state of the above, the drive for the backlash can be performed in the dead zone area, and the advantage that the actual drive operation can obtain the operation feeling consistent with the actual drive can be obtained. is there.

According to the third aspect of the present invention, when a plurality of drive systems are controlled simultaneously, 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, t4 ... backlash drive setting time.

──────────────────────────────────────────────────続 き Continued on the front page (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 method of driving a television camera and a lens thereof, wherein a position control signal corresponding to a distance between a detected position of a driving system and a target position is provided from 0.
In the television camera driving servo circuit that drives and controls the motor, a time equal to or shorter than the time for completely driving the backlash generated by the gears arranged in the drive system is set as the backlash drive setting time. In the backlash drive set time, the position control signal is applied from 0 to control the drive to drive the backlash, and when the backlash drive set time elapses, the position control signal is set to 0. television camera driving servo circuit, characterized in that so as to start a new position control returned to. 2. When the drive system is operated by manual operation means, an operation area for driving the backlash is provided, and the position control signal is returned to the state at the start of driving when the operation time of the backlash operation area elapses. 2. The servo circuit for driving a television camera according to claim 1, wherein the position control is started anew. 3. When simultaneously controlling a plurality of drive systems, a difference in the backlash drive set time is taken into account,
The first drive system according to claim 1, wherein the substantial drive start times of the respective drive systems after the backlash drive are matched.
A television camera driving servo circuit according to claim 13.