JPH0398484A - Speed controller - Google Patents

Abstract

PURPOSE:To eliminate the necessity for adjusting a servo control device and to facilitate switching and changing a characteristic curve by providing a means for digitally converting the displacement amount of a slider, means for storing plural quantities of output characteristic curves for the displacement amount and a means for enabling a desired characteristic curve to be selected out of the above-mentioned characteristic curves. CONSTITUTION:Plural displacement and output characteristic curve data, assigned by a selecting circuit 6 with the digital displacement amount of a slider 2a serving as an address, are stored in a ROM5. A CPU4 reads the displacement amount of the slider 2a as a digital value from an A/D converter while it reads displacement amount and output characteristic curves, assigned by a user, also from the selecting circuit 6. Address data, determined by both the slider 2a and the selecting circuit 6, are input as a speed command to a D/A converter 7 to perform a fine control of a servo motor M.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a servo control device for, for example, a pan head device of a television camera, and in particular, the present invention relates to a servo control device for controlling the speed of a controlled mechanism. This article relates to a servo control device that allows easy low-speed control. [Prior Art] Conventionally, a technology that allows a speed servo control device to easily perform low-speed control of controlled mechanisms such as pan angle, tilt angle, or zoom lens is disclosed in Japanese Patent Publication No. 57-84, for example.
It is known as No. 85. As shown in Fig. 4, a power supply device 1 whose positive and negative supply voltages have the same absolute value and a speed control potentiometer 2 connected between the positive and negative electrodes of the power supply device 1
And variable resistor old], R14, 1? +5, Rl6. Fixed resistor old 1, Rl2, amplifier 11. Servo amplifier 7
, a motor 9, and a tachogenerator lO, and the relationship between the displacement 0 of the slider 2a that slides by rotational operation and the output voltage of the amplifier 11 is made non-linear as shown in FIG. The operability at low speeds, that is, the minute movement of the slider 2a, allows for more precise control.
I'm letting you do it. In addition, the non-linear characteristic curve is the variable resistor R13.
, 114, 115, II+6.

For example, by changing the variable resistors R13 and Rlfl, the fifth
The characteristic curve in the figure changes from curve βl to curve β2, and changes from curve β3 to curve β4 by changing the variable resistor R15,816. [Problem to be solved by the invention] However, in the conventional example described above, a relatively large number of variable resistors must be adjusted in order to obtain a predetermined characteristic curve of the output voltage with respect to the desired slider displacement. However, the adjustment operation becomes complicated. Furthermore, if the characteristic curve of the servo device is changed according to the preference of the person operating the servo device, the variable lever must be readjusted or replaced, which requires a great deal of effort and time. .

An object of the present invention is to provide a device that solves these problems. [Means and operations for solving the problems] The present invention is characterized by a speed control device that controls the speed of a controlled member whose speed rtI4 is controlled by the amount of displacement of a slider for speed control. a conversion means for converting the amount of displacement of the slider into a digital value; a storage means for storing a plurality of characteristic curves of output voltage that change according to the amount of displacement; The present invention includes a selection means capable of selecting a speed of the controlled member, and controls the speed of the controlled member according to a characteristic curve selected by the selection means and an output of the conversion means.

[Examples] Hereinafter, the present invention will be described in detail based on illustrated examples.

FIG. 1 is a block diagram showing an embodiment of the present invention, in which l is a power supply device whose positive and negative supply voltages are equal in absolute value, and 2 is a power supply device connected between the positive and negative electrodes of the power supply device l. A potentiometer 3 is connected to the slider 2a of the potentiometer 2 for position detection, and converts the analog displacement amount of the slider 2a into a digital value. D converter 4 inputs and outputs digital data, and performs logical operation processing. CP0.5 is the displacement angle θ.
6 is a ROM that stores data corresponding to the output voltage of the characteristic curve corresponding to the voltage applied to the motor, that is, the voltage applied to the motor that changes the bang angle, in tab Ie as multiple digital data.
A selection circuit that specifies and selects one from several types of characteristic curve tables stored in the OM, 7 a D/A converter that converts the digital value of the output voltage into an analog speed command voltage, and 8 a selection circuit that selects one from several types of characteristic curve tables stored in the OM. A servo amplifier that drives a servo motor 9 according to a command voltage from a D/A converter 7; 9 is a servo motor that changes the tilt angle or tilt angle of the TV head; 1;
0 is a tachogenerator which is interlocked with the servo motor 9 and controls the servo motor 9 via the servo amplifier 7.

A case will be described in which servo control is performed in the J2 configuration.

The CPU 4 reads the displacement 0 of the slider 2a, which is the operating member of the potentiometer 2, as a digital value from the A/D converter 3.

Next, the CPU 4 reads the setting value of the selection circuit 6 selected by the user, and determines one of the plurality of characteristic curve tables stored in the ROM 5 according to this setting value. As described above, the ROM 5 stores data on voltages to be output according to a plurality of characteristic curves, using the displacement θ as an address, as shown in FIG. FIG. 3 is a graph of the characteristic curve in the table, with the horizontal axis representing the displacement of the slider 2a and the vertical axis representing the output voltage. Let's now assume that the movable range of the slider 2a is θ=-100 to +100 using the digital value of the A/D converter.
Assume that three types of characteristic curve tables A, B, and C have been created in the ROMS. Is it the current displacement θ read by the CPU 4 from the A/D converter 3?

Assume that in step 12, the designation of the selection circuit 6 is selected from the characteristic table B shown in FIG. Then CPU4 reads from ROM5.
Read the data at address E[2.2] and write it to the D/A converter 7 as a speed command signal. Then, the servo motor M is controlled by the output voltage of the D/A converter 7. The selection circuit 6 is composed of, for example, a plurality of switches, and the designation of the characteristic table in the ROMS can be easily changed by turning the switches ON and OFF. Therefore,
The angular movement control of the van angle can freely change the speed of the controlled member as necessary, for example, in accordance with the operation of the operating member or the selection of the selection means. control is possible.

[Effects of the Invention] As explained above, according to the present invention, there is provided a means for converting the amount of displacement of a slider into a digital value, a means for storing a plurality of characteristic curve tables, and a means for storing a plurality of characteristic curve tables. Providing a means for selecting , there is the effect of eliminating the need for circuit adjustment and making it easier to change the characteristics.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing a characteristic curve table stored in the ROM in the embodiment of Fig. 1, and Fig. 3 is a characteristic table shown in Fig. 2. Figure 4 is a block diagram showing a conventional speed servo control device; Figure 5 is a diagram showing the relationship between the displacement amount of the slider and the data value. It is a diagram showing the relationship between the displacement amount of the slider of the servo control device and the output voltage. 1 is a power supply device 2, a speed control potentiometer 3 is an A/D converter 4, a CPU 5 is a ROM, 6 is a selection circuit 7, a D/A converter 8, a servo amplifier 9 is a servo motor, and 1O is a tachogenerator. Figure 3 e Crane, 4-(2)

Claims (1)

[Scope of Claims] In a speed control device that controls the speed of a controlled member whose speed is controlled by the amount of displacement of a slider for speed control, a conversion means converts the amount of displacement of the slider into a digital value. and a storage means for storing a plurality of characteristic curves of output voltage that change according to the amount of displacement, and a selection means capable of selecting a desired characteristic from the plurality of characteristic curves,
A speed control device, characterized in that the speed of the controlled member is controlled according to the characteristic curve selected by the selection means and the output of the conversion means.