JP3662066B2 - Servo circuit for pan head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pan / tilt head servo circuit, and more particularly to control contents of a servo circuit that performs operations such as pan and tilt operations of a television camera, focus and zoom of a lens unit using a position detector.
[0002]
[Prior art]
Conventionally, a TV camera is remotely controlled using a pan head, and the TV camera itself is driven in pan (left-right direction) and tilt (up-down direction), and the focus and zoom of the lens unit are driven. For this purpose, a servo circuit is used. In this servo circuit, the operation position of the drive unit is sequentially detected by a position detector such as a potentiometer, and the drive target can be moved to the control position by feeding back the position detection data.
[0003]
The TV camera drive control also has a preset shot operation function. The preset shot operation is set in advance by setting the operation position such as pan, tilt, etc. as a shot position. The camera is automatically operated. In this preset shot operation, the above-described position control type servo circuit is required, and based on the position data obtained by the position detector, the preset shot position can be accurately operated.
[0004]
[Problems to be solved by the invention]
However, in the above-mentioned conventional servo circuit, the stationary accuracy (position reproducibility) at the operating position depends on the accuracy of the potentiometer, which is the position detector, and the positioning accuracy of the mounting shaft. There was a problem that could not be operated with. That is, there is a so-called backlash between the potentiometer itself and the drive object to the potentiometer, and the presence of this backlash may cause the drive object to go past the preset position and stop.
[0005]
FIG. 9 shows the relationship between the output of the control signal and the output of the potentiometer. As shown in FIG. 9A, if the target position O is at the (0, 0) point of coordinates, The relationship between the output of the control signal and the position can be expressed by a straight line. However, the output of the potentiometer exhibits a hysteresis characteristic as shown in FIG. (B), and as shown in FIG. Considering, in the operation L in the left direction (from the right side to the left side), it is driven to the position O1 beyond the target position O, and in the operation R in the right direction (from the left side to the right side), the position is over the target position O. It will be driven to O2.
[0006]
Therefore, when there is a hysteresis characteristic as described above, the shot operation is stopped at a position shifted from a preset target position. Of course, if a high-precision potentiometer is used and the shaft is positioned with high accuracy, the above deviation can be negligibly small. In this case, avoid high costs. I can't.
[0007]
The above-mentioned stationary accuracy becomes a problem when the lens has a longer focal length than when the lens has a short focal length. For example, when the angle of view is set to a focal length of 2 degrees, the error is ± 1 degree. Depending on the situation, half of the subject to be photographed may be off the screen. Therefore, high accuracy is required when the focal length is long, that is, when observing by enlarging the distance.
[0008]
The present invention has been made in view of the above points, and an object of the present invention is to provide a pan head servo circuit capable of stopping a drive target with higher accuracy than in the past.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a position detector is provided in each drive unit of a television camera, and the drive unit is driven and controlled based on the output of the position detector, and is set in advance. In a pan head servo circuit that performs a shot operation at a shot position of a television camera, a memory for storing the shot position data and data relating to drive control, and a television camera operation that is executed based on the output of the position detector A deviation amount calculating means for calculating a deviation amount between the target position and the actual operation position and storing the deviation amount in the memory, and a shot position control in which the deviation amount stored in the memory is adjusted during the shot operation. Drive control means for outputting a signal. Each of the above-described driving units indicates a driving unit that operates the camera itself to pan and tilt, and a driving unit that performs functions such as zoom and focus of the camera lens unit.
Invention of the second aspect described, the deviation amount calculating means, the setting of the shot position at (preset), calculates the shot position adjusted amount deviation for different operation directions, stores the shot position data in the memory It is characterized by doing.
Invention of the third aspect, wherein, said drive control means, regardless of the operating direction, than the shot position, control of the position of the front by the amount of 1/2 of the displacement amount obtained in the displacement amount calculation means A signal is output.
[0010]
According to the configuration described in the first and second claims, when the TV camera is actually operated from the left and right direction with respect to the target position which is the preset shot position, and the amount of deviation is confirmed, the operation direction is matched. Then, the operation up to the target position is performed again, and the stop position is read by an operation button or the like. A deviation amount is calculated based on the difference between the stop position and the target position, and the deviation amount is stored in the memory. Further, in the setting of the subsequent shot position, the shot position as control data is set for each operation direction. For example, with respect to the control position of the right direction (direction in which motion deviation is considered to occur) in pan driving, The position immediately before the amount of deviation is subtracted is set and stored as a shot position. Therefore, in this rightward movement, the actuator is driven to a position in front of the target position, so that it can be accurately stopped at the target position.
[0011]
According to the third aspect of the present invention, in both movement directions, control is performed so as to drive to a position in front of the shot position by an amount that is ½ of the shift amount. Can be improved. According to this, there is an advantage that control of deviation amount adjustment is simplified.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a configuration of a pan head servo circuit as an example of the embodiment. The top of the diagram is a pan head controller and the bottom is a pan and tilt pan head. In the figure, a joystick 10, a shot button 11, and a rotary encoder 12 are provided on the controller side, and these operating members are connected to an input / output (I / O) unit 14, and the joystick 10 and the I / O unit 14 are connected to each other. Between the two, an A / D converter 13 is provided. A CPU (central processing unit) 15 is provided in connection with the I / O unit 14, and the CPU 15 is connected to the interface 16.
[0013]
On the other hand, on the pan and tilt head side, a CPU 19 is provided connected to the interface 18, and a memory 20 for storing shot position and shift amount data is connected to the CPU 19. That is, the CPU 19 determines the positions P1 and P2 at which an operation in both the left and right directions in pan driving (up and down both directions in tilt driving) is performed with respect to an arbitrary target position P, and the deviation amount PO is set as PO = | P1 -P2 | Calculate by The data of PO, P1, and P2 are stored in the initial setting data area (1) of the memory 20.
[0014]
Further, the CPU 19 adjusts the deviation PO when the shot position is preset, and stores the shot position data (control data) in the memory 20 [shot position data areas (2), (3), etc.]. Control is in progress. That is, in this example, paying attention to the effect of the backlash of the potentiometer (26) during the reversing operation, if it is determined by operating in the direction executed during presetting, for example, the right direction (from left to right) The shot position is memorized as shot position data for rightward movement, and the position that is in the opposite direction to the preset execution, where the leftward (right to left) movement shot position is foremost by the above-mentioned deviation amount is leftward Is stored as shot position data. Therefore, in this case, only the operation in the left direction in which the position shift occurs due to the backlash is adjusted to the front by the shift amount and is controlled.
[0015]
A comparator 23 and a servo amplifier 24 are connected to the CPU 19 via an input / output (I / O) unit 21 and a D / A converter 22, and a motor 25 is connected to the servo amplifier 24. The motor 25 is provided with a potentiometer 26 as a position detector, and a detection signal from the potentiometer 26 is fed back to the comparator 23. The circuits from the comparator 23 to the potentiometer 26 are arranged for each of the pan and tilt driving units, and are also arranged for the driving units such as the focus and zoom of the lens unit. The potentiometer 26 may be another position detector such as a resolver or an encoder.
[0016]
The comparator 23 subtracts the current position control signal output from the potentiometer 26 from the shot position control signal output from the D / A converter 22 and outputs the difference as a drive signal to the servo amplifier 24. To do. Then, the servo amplifier 26 supplies a drive voltage corresponding to the drive signal to the motor 25, and thereby the drive target is driven to the target shot position.
[0017]
The embodiment is configured as described above, and the operation of the pan driving will be described with reference to FIGS. 2 and 3 show the operation of the initial setting mode (deviation amount setting mode) for calculating and storing the deviation amount. In each figure, the operation itself is shown in FIG. The operation on the controller side and the operation on the head side are shown in FIG. First, when an initial setting mode is set with an operation button or the like (step 101), the controller (step 201) outputs an initial setting mode signal to the head under the control of the CPU 15, and the head (step 301) outputs an initial setting data area in the memory 20. Set (1) to a state where data can be stored.
[0018]
Then, the shot position is determined by manual operation using the joystick 10 (step 102). At this time, after the controller (step 202) inputs the joystick output from the A / D converter 13 to the CPU 15, the operation amount is output to the head, and the head (step 302) converts this operation amount into a position control signal. Then, the position control signal is output to the drive unit via the D / A converter 22. Accordingly, the drive unit supplies a comparison output between the position control signal and the current position signal output from the potentiometer 26 to the servo amplifier 24, and the motor 25 is driven by the output of the servo amplifier 24.
[0019]
Here, as shown in FIG. 7A, if the television camera is operated to the target shot position P, after this operation, the shot position data (position data for control) is operated with an operation button or the like. ) P1 is stored (step 103). At this time, since the controller (step 203) outputs a store signal to the head, shot position data P1 is stored in the data area (1) of the memory 20 in the head (step 303).
[0020]
Next, the television camera is moved to a place different from the above shot position (step 104). Here, the controller (step 204) and the head (step 304) perform the same operations as those in step 202 and step 302 described above. Then, the shot is actually executed by the shot button 11 (step 105). At this time, the controller (step 205) outputs a load signal of the shot position data P1 to the head, and the head (step 306) reads the shot position data P1 from the data area (1) of the memory 20, and the D / A converter The output is output to the drive unit 22. Accordingly, in this case, the television camera is pan-driven to the shot position P preset by the motor 25 based on the control position data P1. For example, as shown by an arrow R in FIG.
[0021]
This time, a shot operation is executed from the opposite direction (step 106). At this time, the controller (step 206) repeats the same operations as in steps 204 and 205, and the head (step 306) repeats the same operations as in steps 304 and 305, so that the controller (step 306) is based on the shot position data P1 from the opposite direction. A shot operation is executed. That is, as shown by an arrow L in FIG.
[0022]
Next, in the above operation, it is confirmed from which direction the deviation from the preset position P is executed (step 107). In the operation in the greatly deviated direction, the joystick 10 is manually operated. It reverses and stops at the preset position P (step 108). For example, as shown in FIG. 7A, when the leftward movement L is deviated from the position P, the movement is once returned to the right, moved again to the left, and stopped at the position P. Here, when the vehicle passes by without being stopped at the position P, the operation direction is always matched (in this case, the left direction), and the process is repeated until the vehicle stops just at the position P. The control position when set in this way is P2.
[0023]
Thereafter, the stop position is read with an operation button or the like (step 109). At this time, the controller (step 209) outputs a store signal to the head, and the head (step 309) stores the stop position data P2 in the data area (1) of the memory 20 by the store signal. Finally, the initial setting mode is canceled (step 110), and the controller (step 210) outputs the cancellation signal. At this time, the head (step 310) calculates PO = | P1-P2 | and stores the calculated value PO in the data area (1) of the memory 20 in the next step 311. Such initial setting may be performed by a controller that is actually used as described above, or may be performed using a jig dedicated to initial setting such as a rotary knob (encoder, volume).
[0024]
4 and 5 show operations at the time of presetting the shot position. FIG. 4A shows the operation itself, FIG. 4B shows the operation on the controller side, and FIG. 5 shows the operation on the head side. Is shown. In FIG. 4, the shot position is first determined manually (step 121). At this time, the controller (step 221) inputs the output of the joystick 10 to the CPU 15 as in the case of the initial setting mode. The operation amount is output to the head, and the head (step 321) converts the operation amount into a position control signal and outputs the position control signal to the drive unit via the D / A converter 22, so that the TV camera For example, it is moved to a desired shot position for pan driving.
[0025]
After the shot position is determined, the memory button is pressed (step 122), and then the shot button with the number to be stored is pressed (step 123). At this time, the controller outputs a store signal to the head. (Step 222), and the shot number is also output to the head (Step 223).
[0026]
On the other hand, as shown in FIG. 5, the head detects whether or not the operation direction at the time of presetting is the right direction in step 322. Here, as shown in FIGS. 7B and 7C, considering the case of presetting to the shot position Q, assuming that the movement is in the right direction as indicated by the arrow R in FIG. At 323, the current position is stored in the data area (2) of the memory 20 together with the shot number as shot position data Q1 when operating in the right direction. That is, since the backlash of the potentiometer 26 which is the cause of the deviation of the stationary position generally appears when the direction is reversed, the shot position data Q1 of the rightward movement same as the rightward movement R at the preset time is the target position. Is coincident with the shot position Q. Therefore, in this example, data in the same operation direction is used as it is.
[0027]
In the next step 323, the position Q2 on the right side by the deviation PO calculated in the initial setting mode is stored in the data area (3) of the memory 20 together with the shot number. That is, in this case, only the shot position data Q2 of the leftward movement is set to the position before the shift amount Q1 from the above Q1 for the above reason, and the actual leftward direction is controlled by controlling the drive to this position Q2. In operation, as indicated by the solid line arrow L, it is possible to stop at the target shot position Q.
[0028]
If it is determined in step 322 that the motion is in the left direction, in step 325, the current position is combined with the shot number as the shot position data Q2 when the motion is performed in the left direction (data area of the memory 20). Remember to 3). In the next step 326, the position Q1 on the left side by the deviation P0 is stored in the data area (2) of the memory 20 together with the shot number.
[0029]
The state at this time is shown in FIG. 7C, and if the operation direction at the time of preset is the left direction as indicated by arrow L, the shot position data Q2 of the same left direction operation is Is coincident with the shot position Q. Accordingly, only the shot position data Q1 for the leftward movement is set to a position before the position Q2 by a deviation PO, so that in the actual rightward movement, as indicated by the solid arrow R, It is possible to stop at the target shot position Q.
[0030]
FIG. 6 shows an actual shot operation. FIG. (A) shows the operation itself, FIG. (B) shows the operation on the controller side, and FIG. 6 (C) shows the operation on the head side. First, when a shot button 11 with a certain number is pressed (step 131), the controller (step 231) outputs the shot number to the head. Then, the head inputs the shot number in step 331, loads the shot position data Q1 for the rightward movement of the shot number (step 332), and loads the shot position data Q2 for the leftward movement (step 333). .
[0031]
In the next step 334, it is determined whether the shot position data Q1 is in the right direction from the current position. If the shot position data Q1 is in the right direction (Y), the motor 25 is driven to the shot position Q1 in step 335. On the other hand, if it is determined in step 334 that the direction is leftward (N), the motor 25 is driven to the shot position Q2 in step 336. According to this, as described with reference to FIGS. 7B and 7C, the shift amount in either direction is adjusted and the object position Q is accurately stopped.
[0032]
FIG. 8 shows a comparison with the conventional FIG. 9, and in the operation of the above example, both directions of operation are controlled to the front position as shown by the control signal in FIG. become. Therefore, even when the hysteresis characteristic as shown in FIG. (B) occurs in the potentiometer, as shown in FIG. (C), in the actual drive, the target shot is obtained in both the right direction operation R and the left direction operation L. It is possible to accurately stand still at the position Q.
[0033]
In the above embodiment, both the shot position data Q1 for the rightward movement and the shot position data Q2 for the leftward movement are stored in the memory 20, but one of these data Q1 and Q2 is stored and shot. At the time of execution, the other position may be calculated from the deviation amount PO and output. Also, the initial setting data area (1) of the memory 20 for recording data relating to the deviation amount PO is incorporated in the form of a ROM, and a large number of PO values are written in the ROM, and one PO value is set at the initial setting. It may be selected and used, or various PO values may be written in different ROMs, and the ROMs may be selected and incorporated.
[0034]
Furthermore, the CPU 19 of the head may output a control signal at a position before the shot position by an amount equal to ½ of the above-described deviation amount regardless of the operation direction. That is, for example, in the pan driving described above, a control signal at a position before the amount of (1/2) PO is output in both the leftward movement and the rightward movement with respect to the preset shot position (Q3). The motor 25 may be driven by the above.
[0035]
According to this, at least about 1/2 of the shift amount is improved, and a shift of about 1/2 from the shot position at the time of presetting occurs, but there is no shift due to the direction, and the shot is always stopped at the same position. Therefore, position reproducibility is improved. Further, since there is no need to perform control for each operation direction, there is an advantage that the setting operation and the control configuration can be simplified.
[0036]
In addition, when the backlash amount from the position detector to the driving target is different in each place of the operation range, the operation range is divided into several, for example, when divided into three sections, every three areas. It is also possible to store and set the shift amount (PO). Therefore, in the shot operation in this case, the region of the target position is determined, and the drive target is operated by adjusting the shift amount of the region.
[0037]
【The invention's effect】
As described above, according to the first aspect of the invention, the deviation amount between the target position of the television camera operation to be executed and the actual operation position is calculated based on the output of the position detector, and the deviation amount is calculated. Is stored in the memory and a control signal for the shot position with the deviation amount adjusted is output during a shot operation, so that even if a non-high-precision potentiometer is used, the drive target can be stopped with high precision. This makes it possible to avoid an increase in cost. In addition, when a highly accurate position detector is used, the stationary accuracy can be further improved.
[0038]
According to the second aspect of the invention, when the shot position is preset, the shot position in which the shift amount is adjusted for each different operation direction is calculated, and the drive control is performed based on the shot position data. Exactly done.
[0039]
According to the third aspect of the present invention, the control signal at the position before the shot position by a half of the shift amount obtained by the shift amount calculation means is output regardless of the operation direction. This also has the advantage that the stationary accuracy can be improved and the control of the shift amount can be simplified.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a pan head servo circuit as an example of an embodiment of the present invention;
FIG. 2 is a flowchart showing an operation in an initial setting mode (deviation amount setting mode) in the embodiment. FIG. (A) is an operation itself, FIG. (B) is an operation of a controller, and FIG. (C) is an operation on the head side. FIG.
FIG. 3 is a flowchart showing a continuation of the operation of FIG. 2 in the initial setting mode of the embodiment.
FIGS. 4A and 4B are flowcharts illustrating operations at the time of presetting shot positions according to the exemplary embodiment. FIG. 4A is an operation itself, and FIG.
FIG. 5 is a flowchart showing the operation at the time of presetting the shot position in the embodiment, and is a diagram of the operation on the head side.
6A and 6B are flowcharts illustrating a shot operation according to an exemplary embodiment. FIG. 6A illustrates an operation itself, FIG. 6B illustrates a controller operation, and FIG. 6C illustrates a head-side operation.
7 shows an operation state in the servo circuit of FIG. 1, in which FIG. (A) is an operation state at initial setting, and FIGS. (B) and (C) are operation states at presetting.
FIG. 8 shows the control state in the servo circuit of FIG. 1, where FIG. (A) is the relationship between the output of the control signal and position, FIG. (B) is the relationship between the output of the potentiometer and position, and FIG. It is a figure of an operation state.
9A and 9B show control states in a conventional servo circuit, FIG. 9A shows the relationship between the output of the control signal and the position, FIG. 9B shows the relationship between the output of the potentiometer and the position, and FIG. It is a figure of a state.
[Explanation of symbols]
10 ... Joystick,
11 ... Shot button,
15, 19 ... CPU,
20 ... memory,
24 ... Servo amplifier,
25 ... motor,
26: Potentiometer.

Claims (3)

A position sensor is provided in each drive section of the TV camera, and the above-mentioned drive section is driven and controlled based on the output of the position detector, and a pan head servo circuit that performs a shot operation at a preset shot position of the TV camera. In
A memory for storing data on the shot position and data on drive control;
A deviation amount calculating means for calculating a deviation amount between a target position of the television camera operation executed based on an output of the position detector and an actual operation position, and storing the deviation amount in the memory;
A pan head servo circuit comprising drive control means for outputting a shot position control signal in which the shift amount stored in the memory is adjusted during the shot operation. Said deviation amount calculating means, the time setting of the shot position, calculates the shot position adjusted amount deviation for different operation directions, the first claim, wherein the storing the shot position data in the memory Servo circuit for pan head. It said drive control means, regardless of the direction of movement, than the shot position, and outputs a control signal of position before by the amount of 1/2 of the displacement amount obtained in the displacement amount calculation means A servo circuit for a pan head as set forth in claim 1.

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