SU1517006A1 - Tv camera lens actuator - Google Patents

Abstract

The invention relates to automatic control systems of film and television equipment and can be used to control video camera lenses. The aim of the invention is to increase the reliability of the drive. The start of rotation of the drive is set by the voltage from the setpoint potentiometer, which is amplified by the power amplifier and drives the motor. The rotational speed of the electric motor is stabilized by differentiating feedback connected in series with the feedback potentiometer. When the load moves to the extreme position, the transistor switch disconnects the power from the setpoint potentiometer and the electric motor is stopped due to the differential organization of differentiating feedback. The movement of the motor in the other direction can be set by moving the slider of the setting potentiometer to the feed area of the opposite polarity. 3 il.

Description

The invention relates to automatic control systems of film and television equipment and can be used to control zoom lenses of television and movie cameras.

The purpose of the invention is to improve reliability.

FIG. 1 is a functional diagram of the proposed drive; FIG. 2 shows diagrams explaining the operation of the drive; FIG. 3 - electric drive circuit concept.

The television camera lens drive includes power source 1.

feedback potentiometer 2, electric motor 3, setting potentiometer 4, power amplifier 5, differential amplifier 6, integrating an RC circuit 7, first 8 and second 9 keys.

The drive works as follows

When a signal appears at the output of the amplifiers 5 (Fig. 3) of power due to the amplification of the signal from the setpoint potentiometer 4, the electric motor 3 and the feedback potentiometer connected to the IIHM begin to rotate. On the engine potential

about about a:

2 meter and at the first input of the differential amplifier 6 (Fig. 3), a linearly increasing (or incident, depending on the direction of rotation of the electric motor) voltage 10 appears. The second input of the differential amplifier 6 (Fig. 3) (FIG. 2) enters after passing through the integrating JQ RC circuit 7 (FIG. 3). The passage of a linearly varying signal through an integrating RC circuit is described by the following expressions.

From the feedback potentiometer 2 ij, the signal is removed

and

in

 Kt,

input voltage of the integrating circuit (diagram 20, 10; figure 2); coefficient of proportionality; current time

e integrating RC circuit 7 25 signal

-t / r

RTt-TO-e)

where U. is the output voltage of the integrating circuit (bottom II, FIG. 2) T is the time constant of the integrating circuit, e is the natural basis

logarithm, When t ST can be considered with sufficient accuracy

and

BU

K. (t-T)

In this case, the output of the differential amplifier 6 (Fig. 3), the inputs of which receive signals 10 and 11 (Fig. 2), has a signal 12, which is the difference of these two signals:

and and ,,, -Kt + K (t-T). -KG,

where and is the output voltage of the differential amplifier (Fig. 2, diagram 12). Thus, the output voltage of the differential amplifier is proportional to the coefficient K, i.e. rotation speeds of feedback potentiometer 2 (Fig. 3).

This assignment is used as a feedback signal in the system for speed sensing of the enemy power generator 3, supplied by the first input of the power amplifier 5, the second input of which is supplied by the signal from the reference meter 2.

The speed of the sweep (the motor 3 and the feedback potentiometer 2 associated with it is proportional to the rotation angle of the set potentiometer 4. When the feedback potentiometer 2 slider approaches, the edges of the voltage value at the base and emitter of transistor switches 8 or 9 approach each at a voltage difference of about 0.5 V, the tracer of the corresponding key (8 or 9) closes. Power is removed from one of the stator electrodes of the setpoint potentiometer A, the voltage on the slider of this potentiometer becomes equal to the voltage of the schum, and the drive stops,

In the proposed drive, the reliability is increased by reducing the load on the electric motor (by at least 50%) and by reducing the number of electromechanical devices that have lower reliability than electronic devices. In addition, the drive has a reduced weight and overall dimensions. Decrease of size and weight of the drive, i.e. The reduction in weight and volume of the television camera generally has a positive effect on the operating conditions of the operator, which ultimately affects the quality of the footage.

Claims (1)

Invention Formula A television camera lens drive containing a power source, a feedback potentiometer, an electric motor, a setting potentiometer and a power amplifier, the first input of which is connected to the engine of the setting potentiometer, and the output is connected to an electric motor, the stator of the feedback potentiometer is connected to the power source, and the electric motor is kinematically associated with the motion of a feedback potentiometer, characterized in that, in order to increase reliability, a differential amplifier is inserted into it, integrating H 1 and