JPH0622182A - Drive controller for small sized panhead - Google Patents

Abstract

PURPOSE:To drive the panhead accurately at a speed of a drive command at all times even when a load changes. CONSTITUTION:A small sized panhead having two drive motors 17, 18 driving two orthogonal drive shafts 13, 14 and position sensors 22, 25 is provided with an MPU 30. The MPU 30 obtains the displacement quantity D of the drive shafts 13, 14 per unit time from the detected values of the position sensors 22, 25. Whether or not a difference between an expected displacement quantity T from a drive command signal and the displacement D is within a permissible limit S is discriminated and when the difference is outside of the permissible limit S, a PWM voltage pattern (drive power) is revised and the motor is driven by the drive power. In this case, the revised PWM pattern is revised for storage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a small pan head, and more particularly to a drive control arrangement for a pan head for remotely directing a photographing camera or the like in an arbitrary direction.

[0002]

2. Description of the Related Art ITV (Industrial Television), C
In shooting with a TV camera in CTV (Closed-Circuit Television), TV broadcasting, etc., the shooting camera is remotely operated in order to properly project a target subject or to capture a video in a predetermined area. A pan head is used to change the direction of this shooting camera.

FIG. 6 shows the structure of a pan head device used in a conventional ITV. The pan head 1 has support disks 2 and 3 connected internally to two drive shafts orthogonal to each other. Is provided. For example, when the support disk 2 is attached to the support wall (stand) side, and the photographing camera is attached to the support disk 3 with a dedicated bracket toward the front of the drawing, the photographing camera tilts due to rotation of the drive shaft of the support disk 2. In the (vertical direction), the drive shaft of the support disk 3 rotates to move in the pan (horizontal direction).

Further, the platform 1 is provided with a control unit 5 via a cable 4. The control unit 5 is provided with a joystick 6 for directing and operating the camera in a desired direction. A speed knob 7 for setting the driving speed is arranged. Therefore, in the camera platform 1 of this example, the drive speed of the camera platform 1 can be changed by operating the speed knob 7.

[0005]

By the way, the platform 1 described above is used.
Is relatively large (about 10 cm in length and width) and heavy in weight, but since recent photography cameras have become smaller, lighter, and simpler, the applicant has been downsized. We propose a pan head device. Therefore, the motor itself is downsized as the platform 1 is made smaller.

However, due to the downsizing of the platform 1 and the motor, if the load of the platform 1 changes due to the weight change of the attached photographing camera, the change of the factors over time or the change of temperature or climate, the driving speed changes. There is a problem that it may happen. Therefore, in the case of FIG. 6 described above, the drive cannot be satisfactorily driven at the speed set by the speed control 7, and when the drive is performed at a constant speed without the speed control 7, the speed may extremely slow down.

The present invention has been made in view of the above problems, and an object thereof is to drive a small pan head which can always move a pan head accurately at a speed according to a drive command even when a load changes. It is to provide a control device.

[0008]

In order to achieve the above object, the invention according to the first aspect of the present invention is directed to a motor for driving two drive shafts orthogonal to each other and a position detector for detecting the rotational position of the drive shafts. It is determined whether or not the drive shaft is being driven at the rotation speed set by the drive command signal based on the detection value of the position detector in the small pan head having In this case, a microcomputer for changing the motor drive power according to the drive command signal is provided. Further, the invention according to the second aspect is characterized in that the information on the changed driving power is updated and stored.

[0009]

According to the above construction, the rotational displacement amount of the drive shaft per unit time is obtained based on the output of the position detector, and whether the drive shaft is rotating at the speed according to the drive command is obtained from this displacement amount. To be judged. If the speed is not the drive command, the power supplied to the motor, that is, the drive power is converted to the speed as the drive command, and the motor is rotationally driven by this drive power. Therefore, even if the load changes for some reason, the drive speed of the platform can be stabilized.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the circuit configuration of a drive control device for a small pan head according to an embodiment, and FIG. 2 shows the internal construction of a small pan head. First, in FIG. 2, the platform 10 is configured by connecting a pipe-shaped main chassis 11 made of aluminum extruded material to a sub-chassis 12 which is a wall piece.
The thickness is about 3 cm to 5 cm.
Therefore, the platform 10 of the embodiment is about 1/5 of the size of the conventional apparatus shown in FIG. And
The first storage portion 100 is formed inside the main chassis 11, and the protruding piece of the main chassis 11 and the sub chassis 12 form the second storage portion 200. This first storage section 10
Drive shafts 13 and 14, gear trains 15 and 16 and motors 17 and 18 are arranged at 0, and support discs 20 and 21 for connecting a photographing camera or a support wall are attached to the drive shafts 13 and 14. To be Further, in the second storage section 200, a control circuit board 24 having a position sensor 22 and a control circuit 23, each of which comprises a rotary variable resistor, corresponding to each of the drive shafts 13 and 14, a position sensor 25 and a control circuit. A control circuit board 27 having 26 is arranged.

In FIG. 1, in the above-described platform 10,
A microcomputer (MPU) 30 is provided which executes drive control and controls the rotational speeds of the drive shafts 13 and 14. The MPU 30 is provided with a driver 31 for driving the motor 17 and a driver 32 for driving the motor 18, and the outputs of the position sensors 22, 25 for detecting the rotational positions of the drive shafts 13, 14 are supplied. . In addition, the MPU 30 is provided with an EEPROM 33 in which various information for control is stored.
P for driving the motors 17 and 18 in the EPROM 33
A WM (Pulse Width Modulation) voltage pattern and an expected displacement amount of the drive shafts 13 and 14 corresponding to a command speed, which will be described later, are stored. Further, a driver / receiver (D / R) 34 that transmits and receives control signals is connected to the MPU 30.

On the other hand, a control unit 36 is connected to the platform 10 via a cable, and a microcomputer (MPU) 3 for inputting an operation signal of an operation switch 37 is input into the control unit 36.
8. A driver / receiver (D / R) 39 for transmitting and receiving control signals to and from the platform 10 and a power supply 40 for supplying power to the platform 10 as well as the control unit 36 are provided. In the embodiment, the control signal is serially transmitted between the control unit 36 and the platform 10, and the control unit 36 supplies the control signal based on the operation of the operation switch 37 to the platform 10. .

Therefore, the direct control signal for driving the two drive shafts 13 and 14 is generated by the MPU 30 in the platform 10, and in this MPU 30, the output from the position sensors 22 and 25 is output. Based on the drive shaft 13,1
The displacement amount per unit time of 4 is obtained, and it is determined whether this displacement amount is within the allowable limit of the displacement amount according to the drive command signal transmitted from the control unit 36. Then, when it is determined that the displacement amount is not within the allowable range, a new PWM pattern is formed.

3 to 4, the MPU 3 of the platform 10 is shown.
The control operation at 0 is shown. First, according to the main routine of FIG. 3, the system is initialized at step 301, variables are cleared, mode setting and the like are executed. In the next step 302, all interrupt routines are permitted in a wait loop, and in the embodiment, a timer interrupt routine B, which will be described later, is executed every predetermined time.

FIG. 4 shows a timer interrupt routine B executed when the motor is driven. This timer interrupt routine B is a timer interrupt routine A (not shown) executed when the motor is driven. Is executed by interruption. In FIG. 4, the MPU 30 of the platform 10 is randomly and most preferentially interrupted by the operation command from the control unit 36 (hereinafter referred to as an external interrupt). Directives such as are arranged. Then, in step 402, the displacement amount of the drive shafts 13 and 14 from the time of the check is obtained, but in the embodiment, the position sensor 2 of the drive shafts 13 and 14 is determined.
The displacement amount per unit time is calculated by subtracting the detection value at the time of the previous check from the current detection value based on the detection values (voltage value, pulse value, etc.) of 2,25. At the same time, the current detection value detected at this time of checking is updated and stored as a position value instead of the previous detection value.

In the next step 403, the motors 17, 1 are
It is determined whether or not the wait counter, which is a time setting counter until 8 becomes a steady state, is "N".
If (NO) ", the process proceeds to step 404 to perform decrement, and if" Y (YES) ", step 405.
Then, it is determined whether or not the vehicle is being driven at the speed as instructed. That is, a value obtained by subtracting the predicted displacement amount (T) of the drive shafts 13 and 14 corresponding to the operation (request) command speed from the displacement amount (D) from the previous check obtained in step 402 above. Is the allowable limit value (S)
In other words, it is determined whether or not DT <S, and when the allowable limit value S is exceeded (“N”), the process proceeds to step 406. The predicted displacement amount T is stored in the EEPROM 33 in correspondence with the drive command speed.

In the next step 406, it is judged whether or not the learning counter, which is a time counter for speed learning matching, is larger than β (speed learning matching allowable limit value), and if "Y", Even if the predetermined time has elapsed, the displacement amount is out of the allowable limit value S and the control is impossible. Therefore, in step 407, a warning signal indicating that is output.
On the other hand, if "N", the learning counter is incremented in step 408, and in the next step 409, the displacement amount D from the previous check and the predicted displacement amount T are compared. Then, when D> T, it means that the load is small and becomes faster than the drive command speed, so step 410
And the PWM voltage pattern with a small duty ratio is EEP
It is output based on the information in the ROM 33. For example, in FIG.
As shown in FIG. 7, the pulse width signal shown in FIG. 7B is converted into the pulse width signal shown in FIG. 9A, and the driving power to the motors 17 and 18 is reduced. Also, D <T
In this case, since the load is large and the speed is slower than the drive command speed, a PWM voltage pattern with a large duty ratio is output in step 411, and for example, FIG.
Since the signal having the pulse width of is converted into the signal having the pulse width shown in FIG. 7C, the driving power to the motors 17 and 18 is increased.

In this way, in the embodiment, the error between the drive command speed and the actual displacement speed is constantly checked, and the PWM voltage pattern that is in accordance with the command speed is output from the MPU 30 and the drive power to the motors 17 and 18 is supplied. By changing it, the drive shafts 13 and 14 can be rotated at a stable speed. The drive speed of the platform 10 may be constant at all times, or may be variable by providing a speed setting knob.

If the displacement amount D from the previous check does not exceed the allowable limit value S ("Y") in step 405, the EEPROM 33 is determined in step 412.
The PWM rate within is updated and stored to the current PWM rate. Therefore, when a PWM voltage pattern different from the previous time is output by the above operation, the rate of this newly set PWM pattern is stored, and the drive power value for driving according to the drive command is always learned. become.

In the environment where the platform 10 is used,
The load on the motors 17 and 18 may change due to conditions such as climate or temperature, or due to changes over time, and as described above, by correcting the speed error and learning the accurate drive power value, Accurate drive control is possible.

[0021]

As described above, according to the invention of the first aspect, the microcomputer drives the drive shaft at the rotational speed set by the drive command signal based on the detection value of the position detector. If it is not according to the command, the motor drive power is changed according to the drive command signal, so the pan head is always accurately driven at the speed according to the drive command signal. be able to. Therefore,
When different photographing cameras are attached, the platform can be driven at a stable speed even when the load changes due to changes in temperature or climate, and changes over time.

Further, in the invention according to the second aspect, since the information on the changed driving power is updated and stored, it is possible to newly set the required driving power by learning when the load changes. There is an advantage that you can.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of a drive control device for a small platform according to an embodiment of the present invention.

FIG. 2 is a diagram showing an internal configuration of a camera platform according to an embodiment.

FIG. 3 is a flowchart showing a main routine in a microcomputer operation of the camera platform of the embodiment.

FIG. 4 is a flowchart showing a timer interrupt routine B at the time of motor operation in the microcomputer operation of the platform of the embodiment.

FIG. 5 is a waveform diagram for explaining a PWM voltage pattern used in the example.

FIG. 6 is a diagram showing a configuration of a conventional platform device.

[Explanation of symbols]

 1, 10 ... Platform, 2, 3, 20, 21 ... Support disk, 13, 14 ... Drive shaft, 17, 18 ... Motor, 22, 25 ... Position sensor, 30 ... MPU (microcomputer), 36 ... Control unit .

Claims (2)

[Claims] 1. A small pan head having a motor for driving two drive shafts orthogonal to each other and a position detector for detecting the rotational position of the drive shaft, and the drive based on the detection value of the position detector. A small size equipped with a microcomputer that determines whether or not the axis is driving at the rotation speed set by the drive command signal, and if it is determined that it is not according to the command, changes the motor drive power according to the drive command signal. Drive controller for the platform. 2. The drive control device for a small platform according to claim 1, wherein the changed drive power information is updated and stored.