JPS6231382A - Braking device - Google Patents

Abstract

PURPOSE:To stably and rapidly stop a moving boyd by detecting the variation of a moving state due to a braking force applied to the body, and predicting the variation of a future moving state on the basis of the detcted signal to further apply a suitable braking force. CONSTITUTION:When a controller 10 enters an operation for stopping the rotation of a disc 1 on the basis of a command from an exterior, the movable piece 91 of a switching circuit 9 is switched from a contact 92 to a contact 94 to apply a control voltage to become reverse rotation to the regenerative state through an amplifier 11 to a motor 12.l The pickup rate of a regenerated digital signal obtained from a pickup 2 decreases due to the deceleration of the rotation of the disc 1. Thus, the counted value of a counter 5 is sequentially decreased, and when the counter value becomes the prescribed value, the output of a comparator 7 shifts from L level to H level. After the output of the comparator 7 shifted to the H level, the controller 10 controls the circuit 9 to further apply a braking voltage to the motor 12 for the prescribed period.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an improved braking device for stopping a moving body.
[Prior Art] A conventional device of this type is also disclosed in Japanese Patent Application Laid-Open No. 58-208970. This relates to a disc rotation control device for a Funpact disc player, and particularly relates to stop control of a disc on which digital signals are recorded at a constant recording density. Then, the maximum y paper interval (the maximum interval between two adjacent inversion parts of signal levels) Tmax on the disk is 5.5.
T (- However, T is the period of 4 pulses of input data)
The case where a digital signal is recorded is explained. Then, when the disc rotates and the playback device is in normal playback mode, 1! In this case, the maximum reversal interval of the playback signal is the same as that during recording, and when the playback is completed, a voltage opposite to that in the normal playback state is applied so that the motor that drives the rotation of the disk generates braking torque. is applied. The rotational speed of the disk decreases due to the braking torque, and the paper interval also becomes longer when the reproduction signal is at its maximum. next,
Since no reproduction signal can be obtained when the disk is stopped, if the application of the reverse voltage is stopped when the maximum inversion interval is long enough, the disk will stop.

[Problem that the invention seeks to solve]

The above-mentioned conventional apparatus has been described on the premise that the signal reading means can stably reproduce signals recorded on the disk, regardless of the number of rotations of the disk. However, when the rotation of the disk decreases, the control signal of the signal reading means obtained from the disk becomes longer, and the reversal interval of the reproduced signal, which is recorded information, becomes longer, and the signal contains a strong low frequency component.

Since this low frequency component is superimposed on the signal as noise, stable signal reading cannot be performed. Furthermore, since the signal obtained from the disk is weak, it is usually amplified by an AC coupling circuit.

When this ninth reversal interval becomes longer, waveform distortion occurs and measurement of the maximum reversal interval becomes unstable.

Therefore, in the above-mentioned conventional device, the application of the braking voltage must be released without waiting for the rotation of the disk to sufficiently decrease, which has the disadvantage that it takes a long time from the time when the application of the braking voltage is released until the rotation stops. was there.

The present invention has been made in order to eliminate the drawbacks of the conventional apparatus described above, and provides an apparatus that can quickly and stably stop the rotation even if the reproduced signal becomes unstable due to a decrease in the rotation of the disk. Note that, although an example of a reproducing apparatus for a disc on which digital signals are recorded will be described below, the present invention is not limited thereto.

[Failure to resolve the ode]

This invention detects a change in the motion state due to a braking force applied to a moving body, predicts a future change in the motion state based on the detected signal, further applies an appropriate braking force, and further applies an appropriate braking force to the moving body. This is to stop the operation immediately.

[For production]

The control means in this invention controls the moving speed V of the moving body by braking. is V. /a (where a>1) The braking force is applied for a period T1 up to K, and then for a period of approximately T1×(a-t).

[Embodiments of the invention]

A braking device according to an embodiment of the present invention will be described below with reference to the block diagram of FIG. In the figure, (1) is a disk on which digital signals are recorded, and (2) is this disk (
1) A pickup that reads the recorded signal from the disc (1) by inputting a laser beam and converting the emitted light into an electric signal, and (3) bit synchronization with the reproduced digital signal from the pickup (2). clock signal (PL
CK)e generates PI, L (phase locked loop) circuit, (4) is the signal (PLCK) and pickup (
2) is a signal processing circuit that receives the reproduced digital signal and performs signal processing, and (5) is the reference signal R, FCK from the clock generation circuit (6) (this eyebrow wave number is 7.35kHz).
(7) is a comparator; (8) is a servo circuit that prevents the rotation of the disk (1) in the normal playback state; (9)
is a switching circuit that switches between the Sanibo circuit (8) and the control 61U redundant voltage (-Vcc), (to is a control circuit, aυ is an increase d!
! 1, az is a motor that provides rotational force to the disk (1). Here, the comparator (7) compares the count output value of the counter (5) with a reference value (294 in this case), and when the count value exceeds the cutoff reference value, the output signal becomes low.
A high level ([lK rises from
) from the contact (92) on the servo circuit (8) side to the control voltage (
-Vcc ) side contact (94), the period (T, )K until the output of the comparator (7) rises at time (t2), and the subsequent period (T2) of the contact The movable piece (91) maintains the state and moves at a later time (t,).
This is to switch to the contact (93) on the t-ground side.

In addition, during normal reproduction, the movable piece (91) 1 is in contact with the contact point (92) K on the servo circuit (8) side so that the motor α force is controlled by the output of the servo circuit (8).

Next, the operation of the apparatus shown in FIG. 1 will be explained with reference to the timing diagram of FIG. 2, which shows the operating state of the disk (1) from normal playback to stop.

In the normal playback state, the disk (1) is rotating stably with the servo circuit (8) K, and the digital signal recorded on the disk (1) is transmitted from the pickup (2) to the correct bits.・Leh) fcho=4.321
It is played back at a rate of 8x10'C bits/sec). At this time, the iPLL circuit (3) outputs a bit clock signal (PLCK) synchronized with this. Therefore, the frequency (fplcko) of the output signal (PLCK') is equal to the normal bit rate (fcho). next,
The control circuit α starts to stop the rotation of the disk (1) at time (tl) based on an instruction from an outside (not shown). That is, the switching circuit (9) is the control circuit (11)
Based on the command from the movable piece (91), the contact point (92)
The contact (94) is switched from to the control yjJ voltage (-Vcc) side. Accordingly, the motor a21 has an amplifier α
A controlling voltage (-Vcc) is applied via υ to cause rotation in the opposite direction to that in the normal reproduction state. It should be noted that the counter (5) in the normal playback state performs a count value of the signal (PLCK) in synchronization with the reference signal (RFCK) from the clock generating circuit (6) as described above.

Next, the motor α2 applies the control voltage (-Vcc) to give a torque in the stopping direction to the disc (1), thereby decreasing the rotation of the disc (1). The 0 signal (PLCK'), which also reduces the bit rate (fch) of the reproduced digital signal, outputs a clock signal synchronized with the reproduced digital signal, so its frequency (, fplck) is equal to the bit rate) (
fch), which decreases as the rotation of the sea urchin disk (1) decreases as shown in Fig. 2. Therefore, the count value of the counter (5) also decreases sequentially from the value 588 in the normal playback state. After the busy control voltage (-Vcc) of 0 motor (I) is applied at time (t,), the above count value is counted at time (t2). When the value reaches 294, the output of the comparator (7) changes from low level (G) to high level [F].

On the other hand, the control circuit α [is the movable piece (91) of the switching circuit (9)
to the contact (94) on the voltage (-Vcc) side (time 1
．． ), then start time measurement, and then use the comparator (7)
The moment when the output from (g to l level (time 1)
2) Interrupt time measurement once.

Let the period from this time (t,) to (t2) be (T,). At this time (t2), the count value of the counter (5) has reached 294, which means that the value in the normal playback state is 588, so the rotation speed of the disk (1) has reached % of the normal playback state. It shows that Next, we calculate the reverse torque (-'I'b newton m
) (however, the negative sign indicates braking). Here, the rotational speed of the disc (1) and motor α2 in the normal playback state is (No), and the rotational moment is I (Pc9・5ec2
), their momentum is expressed as (NOx). This momentum is reduced by the reverse torque (-Tb), and after the period (T,) the number of rotations of the disk (1) is (N
o/2). That is, I X (N0/2)
=No.I-Tb-t.

Tb −t, = IX (No/2)
-----------...The formula [2] is obtained. this〔
2] Expression is expressed as when the count value of the counter (5) reaches 294, that is, when the number of revolutions of the disk (1) is (, N0/2
), the reverse torque (-Tb) is further increased from the time (t2) when
is applied to the disk (1) for a period (T2) (however, if the decrease in rotational speed is a linear function with respect to time, then T
=== lil 2) It can be seen that the momentum is zero and the rotation stops. When the count value of the counter (5) reaches 294, the pickup (2) will move the disc (
1) Stop the playback reading. As a result, a reproduced signal cannot be obtained, and the operation of the PLL circuit (3) becomes unstable. Therefore, after the output of the comparator (7) changes from (υ to level) at time (t2), the control circuit a1 applies a control voltage (-Vcc) to the controller α2 for an additional period (T2). Controls the switching circuit (9). This gives the disc (1) a braking momentum of (-Tb-T, ), and the disc (1) stops rotating at time (t, ). At this time (t3), the control circuit αI/fi switching circuit (
The movable piece (91) of 9) is controlled by the control voltage (-Vcc) m
om point (94) empty ground (lAf) 'il1 point (93
) and make contact. As a result, the voltage application to the motor αa is stopped, and the application of the reverse torque to the disk (1) is stopped.

As described above, according to the present invention, the reproduction state becomes unstable! By predicting the time until the stop based on the rotational change of the a, it is possible to obtain a device that can stop the work stably.

In the above embodiment, the rotation speed varies from (No) to (No/
2) We measured the period (T,) until N0/
The period until a (where a>1) is reached is T.

Then, ■・(No/a)=N0・Knee Tb-T.

TbT□=NO-I(a 1)/a No ・I ・(1/a) ='rb H'ro+
1/ (a 1 ) "..." (3) is obtained, and after the rotating machine reaches (No/a ), T. /(a
If braking is applied during -1), the rotation will stop. In addition, in the case where there is friction, the torque e(
Ts), and (Tb+Ts) is (Tb
), the same effect as in the case of formula [2] can be obtained.

Although the above embodiments have been described using a rotating body as an example, the present invention exhibits the desired effect on any type of hitting device whose speed of movement can be detected. Also, part of the process may be performed by software processing, without relying on the above embodiment.

〔Effect of the invention〕

As described above, according to the present invention, a change in speed is detected in a state where the speed can be detected stably, and the time until stopping is predicted, so that an apparatus capable of stably stopping a moving body can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a reproducing device equipped with a braking device according to an embodiment of the present invention, and FIG. M2 is a timing chart of various parts showing the operating state of FIG. 1. In the figure, (1) is the disk, (2) is the pickup, (3
) is a PLL circuit, (5) is a counter, (7) is a comparator,
(9) is a switching circuit, Ql is a control circuit, and α2 is a motor. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Patent Attorney Tadashi Sato Year 1 BI Figure 2 T Continued Amendment Branch: (Voluntary) 1986 1'-5J] 28th and 15 days 5 To the Commissioner of the Agency 1, Indication of the case Patent Application No. 165918-1983 2,
Name of the invention: Braking device 3. Person making the amendment: 10. Agent: Moriya Shiki. (2) "TlX (a 1)" on page 4, line 15 of the specification
Correct J as rTtxi/(a-1)J. (3) "Control voltage" on page 6, line 2 and page 7, lines 7 to 8 of the specification is corrected to "braking voltage." (4) [[2]J [)2] on page 11, line 10 of the specification
Also; correct it as ``31''. The appended claims (Amendment) ``(1) comprising a speed detection means for detecting the speed of motion of a moving body and outputting a speed signal, and a braking means for applying braking to the moving body; For the period T during which the motion velocity V becomes ■./a (however, a>1) due to the braking force, in order to further apply the braking force for the period T1 A braking device characterized in that the braking means is controlled.

Claims (2)

[Claims] (1) It is equipped with a speed detection means that detects the motion speed of a moving body and outputs a speed signal, and a braking means that applies braking to the moving body, and upon receiving the speed signal, the motion speed V_0 is changed to V_0/V_0/ by a braking force. Period T_ until a (however, a>1)
1, the braking device is configured to control the braking means to further apply braking force for a period of approximately T_1×1(a-1) thereafter. (2) The braking device according to claim 1, wherein the value of a is set to 2.