JPS5941541B2 - Non-contact automatic rotation speed measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-contact automatic rotation speed measuring device.

In FIG. 1, a periodic irregular signal obtained from the surface of a rotating body 2 illuminated by a wrap 1 is received by a photoelectric element 3, and its output is converted into a square wave ei by an amplifying waveform shaper 4. , this square wave ei is applied to shift registers 5 and 6 simultaneously.

Shift registers 5 and 6 each consist of a delay element, and are driven by shift pulses P1 and P2 of the same frequency, respectively. Now, P1 and P2 occur or disappear depending on the control inputs A and B of the drive switching device 7 to which the clock pulse P is applied. That is, control input A
is 1, then P depending on whether B is o or 1
1 occurs or disappears, P2 disappears or occurs. Therefore, if we first set A to o, then set A to 1, we get
While A=0, both shift registers 5 and 6 are driven, but from the moment A=1, depending on the value of B, either one of shift registers 5 or 6 stops and the other is driven. The state will be as follows. On the other hand, shift registers 5 and 6 each have storage elements, and have outputs e6i and e6i (i=1, 2, ...).
are applied to each element of the exclusive OR element group 8 as shown in the figure, and their respective outputs ei are applied to the adder circuit 9, D, and output e.

will occur. This e. e to the waveform shaping device 10 to form a pulse train. ' is obtained, and by adding this to the T-flip flop circuit 11, B
The value of is alternately o or 1. Therefore, 5 and 6
are repeatedly stopped and driven, and the rotational speed is measured as described below. First, before measurement, first set A = 0, but in this case, the value of B is 1.
or shift pulses P and P2 regardless of the value of o.
occurs, and therefore shift registers 5 and 6 are both driven. On the other hand, these outputs e5i and e
For 6i, all ei's are always 0 since their counterparts are always the same, so e.
is also o. Next, to start the measurement, set A=1,
A=1 is maintained during the measurement.

Therefore, during this period, A21, B=1 and A=1, B
= 0, in the former case only P2 occurs, and in the latter case only P1 occurs. Let us now assume that the period of the clock pulse P is T, and as an example, the periodic irregular signal obtained from the surface of the rotating body has a waveform as shown in FIG.

First, consider the case where A=1 and B=1. In this case, shift register 5 stops, only shift register 6 is driven, and E5l
remains stopped, but only E6l is at time t=0,T,
2T, . . . change as shown in the figure, and at t228T, the contents of E and i match the contents of E6l. Therefore, Ei at each time changes as shown in FIG. 2b, and the output E of the adder circuit 9 at each time. is the sum of Ei at that time, and 1t=
0, T, 2T, ......, 27T, 28T become 0, 9, 18, ......, 8, 0, respectively.1 These are graphed over time. If expressed as , it becomes as shown in Figure 2c. That is, E at time t228T. becomes the minimum value, and the value of B changes due to the pulse generated at this moment, and the states of A-1 and B-1 become A-1 and B-1.
Transition to state 0. In this case, shift register 6
stops, only 5 is driven, and in Figure 2a, E5l and E6l are exchanged, and the graph in Figure 2c is obtained in exactly the same way as in the case of 1A21 and B21, t=5
A pulse is generated at time 6T, and the state of A=1, B=0 shifts again to the state of A21, B=1, and the same operation is repeated thereafter. Therefore, EO' becomes a pulse train with a period of 28T.1 From this pulse train, the rotational speed of the rotating body can be easily determined. The waveforms actually obtained are shown in Figures 3 and 4. Now, the above is a case where the rotational speed of the rotating body is constant, but next, a case where the rotational speed varies will be explained. As an example, consider a case where a periodic irregular signal obtained from the surface of a rotating body initially has the waveform shown in FIG. 2a with a period of 28T, and then the period changes to 28T. That is, in FIG. 5a, the thick solid line shows the case where the period is 28T, and the thick dashed line shows the case where the period is 28T. First, considering the case of A=1, B=1, that is, the case of the first step, E and i remain stopped as in the case of FIG. 2, but only E6l is at time t=0 and T ,...
... change as shown in the figure, and therefore Ei at these times also changes as shown in FIG. 5b, and E at each time changes. is t=0,T,...
... 0, 9, ... at 27T1 and 28T, respectively.
. . . 12, 11, 1 If these are expressed in a graph over time, the result will be as shown in Figure 5c. That is, E at time t-28T. becomes a minimum value, and due to the pulse generated at this moment. The state of A=1, B=1 transitions to the state of A=1, B20, ie, the second step. In this case, it is the case after t=29T, and the 1st 6th
As shown in Figure a, E6l maintains its state at t=28T, and E,i remains at time t=29T, 30T,
. . . changes as shown in the figure, and therefore Ei at these times also changes as shown in FIG. 6b, and E is calculated at each time. is t=29T, 30T
,..., 12 at 55T and 56T, respectively.
, 17, . That is, E at time t=56T. becomes the minimum value and 1 due to the pulse generated at this moment. A=1, B=O
The state shifts to the state of A-1, B=1, that is, the third step. In this case, it is after t=57T, and as shown in Figure 7a, E,i maintains the same state as when t=56T, and E6l is at time t=57T,
58T, .

is t-57T, 58T, 76T, 77
In T, respectively, 11, 22, ..., 18
. That is, t=77T
E at the time of. is the minimum value. Due to the pulse generated at this moment, the state of 1A=1, B=1 shifts to the state of A=1, B:0, that is, the fourth step. Thereafter, E changes over time from the states of each step obtained in the same manner. If expressed in a graph, it will be as shown in FIG. 8.1 In the third step, the period changes from 28T to 21T, and from the seventh step onwards, the same waveform with a new period of 21T is repeated. In other words, even if the rotation speed changes during measurement, it can automatically adapt to the new rotation speed, and
1 by increasing the storage element r of the shift register.
The non-contact automatic rotational speed measuring device according to the present invention, which can increase the rotational speed measurement range and improve the measurement accuracy, has the configuration and operation as described above. , has the following characteristics. 1)
Since automatic measurement over a wide range is possible and there is no need to change the speed range according to the slowness of one rotational speed, so-called one-tap type measurement is possible.

2) It is possible to sufficiently track sudden changes in rotational speed.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the configuration of the present invention, Figures 2 to 4 are waveform diagrams when the rotational speed is constant, and Figures 5 to 8 are waveform diagrams when the rotational speed is varied. Show 5. 1: Lamp, 2: Rotating body, 3: Lightning element, 4: Amplification waveform shaper, 5: Shift register, 6: Shift register, 7
: drive switching device, 8: exclusive OR element group, 9: addition circuit, 10: waveform shaping device, 1011: T-flip-flop circuit.

Claims (1)

[Claims] 1 Two shift registers, both of which are composed of r delay elements, receive periodic irregular signals obtained from the surface of the rotating body, and shift pulses P_1 and P_2 of the same frequency that drive each shift register are simultaneously transmitted. ,
Alternatively, a drive switching device that can generate only one of the signals, a group of exclusive OR elements provided so that an exclusive OR is formed between the outputs of mutually corresponding delay elements of both shift registers, and these an adder circuit that adds r outputs obtained from each element, a wave shaping device that converts the output of the adder circuit into a pulse train so as to generate one pulse per rotation, and a wave shaping device that converts this pulse train into one pulse. A non-contact type automatic rotation speed measurement device is equipped with a T-flip-flop circuit that alternately stops either P_1 or P_2 every time the pulse train occurs. Device.