JPH05334799A - Motor controller for still video device - Google Patents

Abstract

PURPOSE:To inexpensively obtain the motor controller for the still video device capable of optimally controlling the rotation of a spindle motor in spite of position in the radial direction of a magnetic head at an FD without complicat ing or enlarging the conventional controller and system. CONSTITUTION:This controller is constituted so that the loop gain of a spindle motor 1 is corrected in accordance with the radial direction position of a magnetic heat 12 to detect that the position in the radial direction of the magnetic head is at a reference place and a counting is carried out by an up-down counter 19 for every time of moving the magnetic head. Thus, the radial direction position of the magnetic head is detected by a simple constitution, a gain correction is carried out for the load fluctuation due to this position and thus, without enlarging or complicating the controller the rotation of the spindle motor is optimally controlled and a cost is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a still video device for recording an image of an object received by a light receiving element as an image signal on a flexible disk or reproducing the image.
In particular, the present invention relates to a motor control device of a still video device for feedback controlling a spindle motor for rotating this flexible disk.

[0002]

2. Description of the Related Art Recently, a flexible disk (hereinafter, referred to as FD in this specification) is used to capture an image taken in the same manner as an ordinary camera.
Is abbreviated. A still video system for magnetically recording and reproducing an image by using a still video camera for recording in (1) and a device for reproducing the image from the FD has been developed and commercialized.

The FD in such a still video system is usually divided into 52 tracks, and the screen and audio data are recorded on each of the first to 50th tracks. The 51st track is an empty track and the 52nd track is an optional cue track. Set this FD in a still video camera or playback device, and in the case of NTSC system, 3
The magnetic head is made to access a desired track by constant rotation at 600 rpm to actually record and reproduce an image.

Here, the phase of the FD as described above must be always matched with the image signal when the image is recorded, for example. Conventionally, the speed is obtained by comparing the FG pulse detected several times in one rotation with a reference clock with marks provided on the FD rotary table at equal intervals in the circumferential direction, and a specific position near the center of the FD. PG obtained by detecting one PG yoke provided in
The phase is obtained by comparing the pulse and the vertical synchronizing signal (V sync) obtained from the image signal, and the motor is feedback-controlled from these data.

[0005]

However, in the conventional method as described above, the sliding resistance generated by the contact of the magnetic head with each track of the FD, that is, the load of the spindle motor is not on the outer peripheral side of the FD. Since it greatly differs from the inner circumference side, it is difficult to secure the gain margin of the control loop when the load variation due to the track position of the magnetic head and other load variation such as environmental change and FD type are combined, and proper rotation is ensured. It was difficult to control. Therefore, it is possible to change the rotation control loop according to the track position of the magnetic head, but if an expensive position sensor such as a position meter or a linear sensor is provided to detect the track position of the magnetic head, the device will be There is a problem that the structure becomes complicated as the size increases, and the cost further rises.

In view of the above problems of the prior art, the main object of the present invention is to make the spindle independent of the radial position of the magnetic head in the FD without complicating or increasing the size of the conventional apparatus or system. (EN) It is an object to provide a motor control device of a still video device, which can appropriately control the rotation of a motor, at low cost.

[0007]

According to the present invention, there is provided a still video device for receiving an image of a subject by a light receiving element and recording the image signal on a flexible disk or reproducing the image signal. In a motor controller for feedback controlling a spindle motor for rotating the flexible disk, the radial position of the magnetic head for exchanging image information with the flexible disk is detected. And a means for changing the loop gain of the control according to the radial position of the magnetic head, and the radial position detecting means of the magnetic head detects that the magnetic head is at the reference position. Means and an up / down counter that counts each time the magnetic head moves in a predetermined unit in the radial direction. This is achieved by providing a motor control device for a still video device, which is characterized in that the radial position is detected from the count value of the up-down counter.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of a motor control device in a still video device to which the present invention is applied.

A spindle motor 1 for driving an FD (not shown) is drive-controlled by a motor control circuit 2 composed of a microcomputer via a variable gain amplifier 3 and a drive circuit 4. In this motor control circuit 2,
F through the comparator 5 and the amplifier 6 to which the reference voltage is supplied
The G sensor 7 is connected, and the PG sensor 11 is connected via the comparator 9 and the amplifier 10 to which the reference voltage is also supplied.

Here, the FG sensor 7 is a sensor for providing, for example, 16 marks at equal intervals on the rotating body in the circumferential direction, and sequentially reading the marks. The FG pulse from the FG sensor 7 controls the motor. The circuit 2 detects the rotational speed and controls the speed based on the detected rotational speed.
Further, the PG sensor 11 detects a PG core provided at only one position in the circumferential direction on the FD and inputs a PG pulse to the motor control circuit 2. Then, the motor control circuit 2 detects the phase, and the phase control is performed based on the detected phase.

A system controller 15 is connected via a drive circuit 14 to a step motor 13 for driving the magnetic head 12 for accessing and recording and reproducing an image in the FD in the tracking direction. The system controller 15 includes a photo coupler 16 for detecting that the magnetic head 12 is at the reference position.
7 and the amplifier 18 are connected. Further, the system controller 15 is connected to an up / down counter 19 for adding / subtracting the moving direction and the moving amount of the magnetic head 12 when the magnetic head 12 is at the reference position as a starting point (0). The up / down counter 19 is adapted to correct the gain of the variable gain amplifier 3 to the spindle motor 1 according to the track position of the magnetic head 12 via the resistance ladder 20 as a D / A converter.

[0013]

As is apparent from the above description, according to the motor control device of the still video device of the present invention,
The loop gain of the spindle motor is corrected according to the radial position of the magnetic head, the radial position of the magnetic head is detected to be at the reference position, and the up / down counter is used each time the magnetic head moves. With the counting configuration, the radial position of the magnetic head can be detected with a simple configuration, and gain correction can be performed for load fluctuations due to this position, so that the device does not become large or the structure does not become complicated, and the spindle The rotation of the motor can be controlled appropriately and the cost is reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a video still camera to which the present invention is applied.

[Explanation of symbols]

 1 spindle motor 2 motor control circuit 3 variable gain amplifier 4 drive circuit 5 comparator 6 amplifier 7 FG sensor 9 comparator 10 amplifier 11 PG sensor 12 magnetic head 13 step motor 14 drive circuit 15 system controller 16 photocoupler 17 comparator 18 amplifier 19 Up-down counter 20 Resistance ladder

Claims (1)

[Claims] 1. In a still video device for receiving an image of an object by a light receiving element and recording or reproducing the image signal on a flexible disk, a spindle motor for rotating the flexible disk is fed back. A motor control device for controlling, which detects a radial position of a magnetic head for transmitting and receiving image information to and from the flexible disk, and the control according to the radial position of the magnetic head. And a means for changing the loop gain of the magnetic head, the means for detecting the position in the radial direction of the magnetic head detects that the magnetic head is at the reference position, and the magnetic head moves in a predetermined unit in the radial direction. An up-down counter that counts each time, and the radial direction is calculated from the count value of the up-down counter. A motor control device for a still video device, which is characterized by detecting a position.