JPH087226B2 - Method of determining the direction of rotation of a rotating body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for determining a rotating direction of a rotating body, and in particular, based on the pulse level of one of two phase pulses generated with the rotation of the rotating body with respect to the other pulse edge. The present invention relates to a determination method for determining the rotation direction of a rotating body.

BACKGROUND ART A playing device for a recording medium on which video information is recorded, for example, a video tape recorder (VTR), is provided with a rotating body in an operating portion, and the rotating body is operated to rotate a tape in a tape traveling direction corresponding to a rotation direction and a rotation angle. There is one equipped with a video reproduction speed control device for controlling the reproduction direction and the reproduction speed by setting the traveling speed.

In order to determine the rotation direction of the rotating body in this video reproduction speed control device, generally, pulse generating means for generating two-phase pulses in accordance with the rotation of the rotating body is provided, and as shown in FIG. Depending on whether the level of one pulse (a) of the two-phase pulses supplied from the pulse generating means is the high level or the low level of the other pulse (b, c) with respect to the falling edge, for example, It is determined whether the rotation direction is the forward direction (hereinafter referred to as FWD direction) or the reverse direction (hereinafter referred to as REV direction).

By the way, there are a contact type and a non-contact type as the pulse generating means. Especially, in the contact type, as shown in FIG. Therefore, the rotation direction may be erroneously determined. Conventionally, this is dealt with by inserting a chattering absorption circuit on the output side of the pulse generation means, but since the chattering absorption circuit causes waveform distortion and changes the duty ratio, it is easy to make an erroneous determination especially at high speed rotation. There was a problem. That is, the duty ratio is 50%
If the chattering is too much, it is necessary to sufficiently dull the waveform, and the path duty after waveform shaping becomes long. At this time, there is no problem if the edge can be detected without fail, but when the edge is detected by the level detection by software, there is a possibility that the determination of the rotation direction may be erroneous due to the delay of the processing. Especially, when the rotating body is rotated at a high speed, this effect becomes remarkable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a rotation direction determination method for a rotating body that enables accurate direction determination without being affected by chattering.

The method for determining the rotation direction of a rotating body according to the present invention is to determine the number of pulses when the pulse level of one of the two-phase pulses generated with the rotation of the rotating body to the other pulse level is high within a predetermined time. The number of pulses at the low level is counted respectively, and the rotation direction of the rotating body is determined based on the pulse level with the larger count number.

Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a recording medium playing device, for example, a video disc player to which the method for determining the rotating direction of a rotating body according to the present invention is applied. In the figure, a video disk 1, which is a recording medium, is rotationally driven by a spindle motor 2, and the recorded information is read by an optical pickup 3. This pickup 3
Are a laser diode as a light source, an optical system including an objective lens, a four-division photodetector for receiving the light beam reflected by the video disc 1, and an optical axis direction of the objective lens with respect to the information recording surface of the video disc 1. A focus actuator for controlling the position of the optical disc, a tracking actuator for controlling the position of the main beam spot emitted from the pickup 3 in the radial direction of the disk with respect to the recording track, and the like are built in. The read output of the pickup 3 is
After passing through the RF amplifier 4, it is demodulated by the demodulation circuit 5 to be a video output.

A jog dial 6 which is a rotating body used for controlling a reproduction direction and a reproduction speed is rotatably provided on an operation unit of a player main body, a remote controller (remote operation device), or both. A substrate 7 is fixedly arranged coaxially with the jog dial 6. On this substrate 7, a large number of conductors are electrically connected to each other and provided concentrically around the rotation shaft 6a of the jog dial 6 so that the conductor width and the conductor intervals are equal at a constant angular interval. A
Phase conductor group 8 is formed, and the A-phase conductor group 8 is provided on the inner peripheral side.
A conductor group 9 of B phase is configured by electrically connecting the same number of conductors to each other and concentrically provided so that the conductor width and the conductor interval are equal at a constant angular interval.
A phase difference of an electrical angle of 90 ° is provided between the phase and B-phase conductor groups 8 and 9. The power supply voltage + Vcc is applied to the A-phase and B-phase conductor groups 8 and 9 via resistors R _A and R _B. An annular conductor 10 is further provided concentrically on the inner peripheral side of the B-phase conductor group 9, and the annular conductor 10 is grounded.

In addition, the brush 11 is fixed to the actuator 11 that is fixed to the rotary shaft 6a of the jog dial 6 and rotates integrally with the jog dial 6.
3, 14 are electrically connected to each other, and when the jog dial 6 rotates, the brushes 12, 13 intermittently contact the conductors of the A-phase and B-phase conductor groups 8, 9 to make the brush 14 Is in constant contact with the annular conductor 10. Therefore, when the jog dial 6 rotates, the brush 1 is attached to the output terminals 15 and 16 of the A phase and B phase respectively.
A waveform having a ground level is obtained during a period in which 2, 13 are in contact with each conductor of the A-phase and B-phase conductor groups 8, 9. These output waveforms are shaped by the waveform shaping circuits 17 and 18, and are supplied to the controller 19 as two-phase pulses having a phase difference of 90 °. With the above, pulse generating means for generating two-phase pulses in conjunction with the rotation of the jog dial 6 is configured.

The controller 19 is composed of, for example, a microcomputer, determines the rotation direction of the jog dial 6 based on the two-phase pulses, sets the reproduction direction corresponding to the rotation direction, and counts the pulses for each rotation direction, and counts this. The reproduction speed corresponding to the rotation angle of the jog dial 6 is set based on the number, and the drive control of the drive circuit 20 for driving the tracking actuator (not shown) incorporated in the pickup 3 is performed. In the video disc player, the reproduction direction and the reproduction speed are determined by the jump method of the main beam spot by the pickup 3, the jump timing and the number of tracks to jump. This jump method is well known, and a description of its specific operation is omitted here.

Next, the procedure of the rotation direction determination method according to the present invention executed by the processor of the controller 19 will be described in the second section.
A description will be given according to the flowcharts of FIGS. Note that FIG. 2 shows a pulse detection routine executed by interrupt processing every 500 μsec, and FIG. 3 shows 100 msec.
The rotation direction determination routine executed by each interrupt process is shown.

In FIG. 2, the processor first determines whether or not the level of the phase A pulse is high (step S
1) If the level is high, a level flag indicating that is set (step S2), and then the process returns to the main flow. When the level of the A-phase pulse is low, it is judged whether or not the previous level flag has already been set (step S3). If it has not been set, the A-phase pulse continues to be low. Since it is in the level state, it returns to the main flow.

On the other hand, if the level flag is set, A
Since the phase pulse level has changed from high level to low level, clear the level flag (step S
4) It is determined whether or not the level of the B-phase pulse is high (step S5). When the level of the B-phase pulse is high, the FWD direction counter is incremented (step S6), and when it is low, the REV direction counter is incremented (step S7). FW
As the counters in the D direction and the REV direction, counters built in the processor may be used, or dedicated counters provided outside may be used.

By repeating the above operation, the change point of the A phase pulse from the high level to the low level is detected every 500 μsec, and depending on the level of the B phase pulse at this change point, the FWD direction or R
By incrementing the counter in the EV direction, the number of pulses for each rotation direction is integrated for 100 msec in which the rotation direction determination routine of FIG. 3 is executed.

In FIG. 3, the processor determines whether or not the count values of the counters in the FWD direction and the REV direction in the preceding pulse detection routine are equal (step S12), and if they are different, compare the two count values. The rotation direction of the jog dial 6 is determined by (step S1
3). That is, if the count values in the FWD direction and the REV direction are equal, it is determined that the jog dial 6 is not moving, and the FW
If the count value in the D direction is larger than that in the REV direction, it is determined that the rotation direction of the jog dial 6 is the FWD direction, and if the count value in the REV direction is larger, it is the REV direction.

When the rotation direction of the jog dial 6 is determined to be the FWD direction, the value obtained by subtracting the value in the REV direction from the count value in the FWD direction is set as the effective pulse number (step S14), and then the effective pulse number is, for example, "4". Is larger than "4" (step S15), and if larger than "4", the number of effective pulses is fixed to "4" (step S16), and then the FWD direction flag is set (step S17). . Similarly, when it is determined to be the REV direction, a value obtained by subtracting the count value in the FWD direction from the count value in the REV direction is set as the effective pulse number (step S18),
Subsequently, it is determined whether or not the effective pulse number is larger than "4" (step S19), and if it is larger than "4", the effective pulse number is fixed to "4" (step S20). The rear REV direction flag is set (step S21). The number of effective pulses is limited to "4" because the reproduction speed set by the jog dial 6 is set to four stages in each direction, and the number is arbitrary.

Subsequently, it is determined whether or not the previous effective pulse number is "0" (step S22), and if it is not "0", it is determined whether or not the current effective pulse number is equal to the previous effective pulse number (step S22). S23). If they are equal, it can be considered that the jog dial 6 is rotating at a constant speed, so the effective pulse number at this time is decoded and stored in the output buffer (step S2).
Four). Decoded effective pulse number code is WFD or RE
A direction code based on the V direction flag is also included, and the relationship between the number of effective pulses, the effective pulse number code, and the reproduction speed is as shown in the table below, for example.

That is, the rotation direction and the rotation angle of the jog dial 6 can be known from this effective pulse number code, and therefore, the reproduction direction and the reproduction speed of the image can be set based on this code. The reading of the effective pulse number code from the output buffer and the setting of the video reproduction direction and reproduction speed based on this code are executed in another routine.

To summarize the above procedure, as shown in FIG. 6, the B-phase pulse (b) with respect to the falling edge of the A-phase pulse (a) at a certain fixed time t (for example, 100 msec).
Pulses are counted according to the direction determined by the level of, the absolute value of the difference is used as the number of pulses, and the direction with the larger number of pulses is used as the direction. In the case of the example shown in FIG. 6, the FWD direction has 1 pulse and the REV direction has 7 pulses, so the direction is R
EV direction, the number of pulses is 6 pulses. The number of effective pulses is fixed at "4". By doing this, even if there is chattering, the direction determination will not be erroneous,
Even if the jog dial 6 suddenly changes in direction (for example, it is alternately rotated at high speed in both forward and reverse directions), a natural feeling is obtained as an operation. Further, when the chattering is small, the chattering absorption circuit is not necessary, and even when the chattering is large to some extent, the waveform does not have to be extremely rounded, so that the duty change can be suppressed to be small and the accurate direction determination can be performed.

If it is determined in step S22 that the previous effective pulse number is "0", it means that the jog dial 6 was not rotating last time, so the process directly proceeds to step S24 and the effective pulse number code of this time is set. Store in output buffer.
After storing the effective pulse number code of this time in the output buffer, the effective pulse number of this time is set as the previous effective pulse number (step S25), and each counter of the FWD direction and the REV direction is initialized (steps S26, S27), Then return to the main flow.

If it is determined in step S23 that the effective pulse number of this time is different from that of the previous time, it can be considered that the rotation speed of the jog dial 6 is not constant. Therefore, the process directly proceeds to step S25 to output the effective pulse number code of this time to the output buffer. Stop storing and use the previous effective pulse number code to set the video playback direction and playback speed.
That is, if the effective pulse number of the previous time and the current effective pulse number are different once, the previous pulse code is used without updating the effective pulse number code of the output buffer, and the effective pulse number of the output buffer is determined only when it is determined that they are equal twice consecutively. Update the number code. By doing so, even if the effective pulse number code obtained every 100 msec is different due to the fact that the jog dial 6 cannot be rotated at a constant speed, the reproduction direction and the reproduction speed of the image corresponding to this effective pulse number code are changed each time. Since it is not set, there is no unnatural feeling in double-sided feeding. Fig. 4 shows A in the FWD direction.
Phase pulse (a), current effective pulse number code (b), and effective pulse number code (c) stored in the output buffer
Shows the relationship.

If it is determined in step S12 that both count values in the FWD direction and the REV direction are equal, it is considered that the jog dial 6 has not moved, or the jog dial 6 has been alternately rotated in both directions. Is set to "0" (step S28), and the process returns to the main flow through steps S26 and S27.

In addition, in the above-described embodiment, the case where the invention is applied to the determination of the rotation direction of the jog dial 6 in the video disc player has been described, but the invention is not limited to this.
It can also be applied to the determination of the rotation direction of a general rotating body. Further, the pulse generating means for generating the two-phase pulse is not limited to the contact type, but may be a non-contact type such as an optical type, but the present invention is a contact type that easily causes chattering. It is especially effective when applied to.

EFFECTS OF THE INVENTION As described above, according to the rotation direction determination method of the present invention, the pulse level of one of the two-phase pulses generated with the rotation of the rotating body to the other pulse level within the predetermined time The number of pulses at high level and the number of pulses at low level are each counted, and the rotation direction of the rotating body is determined based on the pulse level with the larger count, so rotation is not affected by chattering. Stable and accurate direction determination is possible from low speed to high speed rotation of the body.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a video disc player to which the method for determining the rotation direction of a rotating body according to the present invention is applied, FIG. 2 is a flow chart of a pulse detection routine executed by a processor, and FIG. 3 is executed by the processor. FIG. 4 is a flowchart showing the procedure of the rotation direction determination method according to the present invention. FIG. 4 is a pulse (a) of phase A in the FWD direction, effective pulse number code (b) of this time, and effective pulse number code stored in the output buffer. FIG. 5 is a waveform diagram for explaining the principle of rotation direction determination based on two-phase pulses, and FIG. 6 is a waveform diagram for explaining the operating principle of the present invention. is there. Explanation of symbols of main parts 1 ... Video disc 3 ... Optical pickup 6 ... Jog dial 8 ... A phase conductor group, 9 ... B phase conductor group 12 to 14 ... Brush, 19 ... Controller

Claims (1)

[Claims] 1. A determination method for determining a rotation direction of a rotating body based on a pulse level of one pulse edge of a two-phase pulse generated with the rotation of the rotating body, the pulse direction being within a predetermined time. The pulse number when the other pulse level with respect to the one pulse edge in is high level and the pulse number when the other pulse level is low level are respectively counted, and the rotation of the rotating body is based on the pulse level with the larger count number. A determination method characterized by determining a direction.