JPH0667729A - Pulse counting device - Google Patents

Abstract

PURPOSE:To control a position or a rotation angle of an object to be controlled with high accuracy and with high throughput by constituting the device so that a split rate of an interpolating means is varied in accordance with a specific expression by using a detecting means and a counter, and the lower bit of an output is not used by synchronizing with a variation of this split rate. CONSTITUTION:An incremental encoder 1 generates a sine wave-like signal in accordance with a displacement amount of position information or a rotation angle information. An interpolator (N-th power folds of 2) generates a pulse signal by splitting this sine wave, and a second counter 4 counts a pulse from this interpolator 2, and outputs a position signal by a binary bit train. According to this invention, a split rate of the interpolator 2 is varied to an N-the power (N: a natural number) of 2, and it is possible to constitute it so that th lower bit of an output is not used by synchronizing with a variation of this split rate. By setting the split rate of the interpolator 2 to N-th power folds of 2, and executing a variation of the split rate and a shift of the output, a moving speed can be increased, while holding high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse counting device suitable for detecting the position of a positioning device.

[0002]

2. Description of the Related Art Conventionally, in order to perform positioning control,
This kind of pulse counting device is used.

A pulse counting device having an interpolator is shown in FIG.
It is configured like. Where 1 is the detector, 2 is the interpolator,
3 is a pulse counter. Further, FIG. 6 shows signals at respective points in FIG. 5, where (a) is a sine wave signal having a phase difference of 90 degrees, (b) is a pulse divided by an interpolator, and (c) is It is a bit string of the counting result.

Here, the interpolator 2 is fixed in advance how many times the pulse of the original signal should be output, and cannot be changed.

[0005]

However, in the above conventional example, since the division ratio of the interpolator is fixed, there are the following drawbacks.

That is, when performing highly accurate positioning, the resolution of the detector itself is increased and the division rate of the interpolator is increased to improve the detection accuracy. As a result, the number of pulses per displacement amount increases.

On the other hand, in order to increase the throughput as a positioning device using a pulse counting device, it is necessary to increase the moving speed and shorten the moving time. For example, when the precision is doubled, the pulse count speed must be doubled in order to make the movement time the same.

Therefore, high accuracy and high throughput are required.
In order to achieve one of the two goals, the pulse count speed of the counter becomes a bottleneck, and there is a drawback in that there is a trade-off between emphasis on accuracy and throughput.

Therefore, in view of the above points, an object of the present invention is to provide a counter device configured to control the position or rotation angle of a controlled object with high accuracy and high throughput.

[0010]

In order to achieve the above object, the present invention divides the sine wave by a detecting means for generating a sine wave signal according to a displacement amount of position information or rotation angle information. An interpolation means for generating a pulse signal and a counter for counting the pulses from the interpolation means and outputting a position signal as a binary bit string are provided, and the division ratio of the interpolation means is 2 N (N). : Natural number), and the lower bits of the output are not used in synchronization with the change of the division ratio.

[0011]

In the present invention, by changing the division ratio by the interpolating means, it is possible to improve the positioning accuracy and shorten the moving time of the controlled object, and it is necessary to perform highly accurate positioning and high throughput. It can be used for position detection of positioning devices and the like.

That is, in order to solve the above-mentioned problems, the present invention utilizes the fact that the accuracy requirement for the speed of the controlled object during movement is lower than the accuracy requirement for the position, and the interpolation means is adapted according to the moving speed. The dividing ratio is made variable and the accuracy is low at high speed to reduce the limitation of the pulse count speed to shorten the moving time, and at low speed, counting is performed with high accuracy to maintain the positioning accuracy. As a result, the contradictory goals of high accuracy and high throughput are realized together. Furthermore, if the division ratio of the interpolation means is set to the Nth power of 2, the change in the division ratio can be absorbed by not using the lower bits in the binary output bit string. Therefore, for the side using the information of the counter. There is no need to consider changes in the division ratio.

[0013]

EXAMPLES Examples of the present invention will be described in detail below.

Embodiment 1 FIG. 1 shows an embodiment of the present invention in which an incremental encoder is used as a detector. In this figure, 1 is an incremental encoder, 2 is an interpolator (2 times the Nth power),
3 is a first counter for counting the output of the interpolator, 4 is a second counter for counting the original signal of the encoder output, 5 is an output register (N bits) of the first counter,
6 is the output register of the second counter (the hatched portion in 5, 6 is for indicating the length of the entire bit string and does not actually exist), and 7 is the sum of the first output register and the second output register. , 8 is an output register of this pulse counting device, 9 is a switcher which checks the time change rate of the pulse and generates a switching signal, and 10 is a signal from the switcher 9 which indicates the count result of the first counter. This is a switch for determining whether to add to the adder 7.

Next, the operation of this embodiment will be described with reference to FIG. Here, it is considered to perform acceleration and deceleration from A to B for movement and positioning. The speed changes with time as in a). At the speed of A, the switch 9 outputs a switching signal, and at a speed faster than A, the switch 10 is opened (lower side in the figure),
Do not use the first counter output. Therefore, only the second counter output is used from a to u. Figure 2
B) indicates the position change at this time. Between A and C, a high-precision region using the first and second counter outputs, C to D
During the period, the moving speed is high, and thus the low-accuracy region uses only the second counter output. Since the switch 10 is switched by c, the final positioning between D and A is performed in the high precision area.

Embodiment 2 FIG. 3 shows a second embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 3, reference numeral 11 is a switcher which changes the division ratio of the interpolator 2 and the shift amount of the output of the first counter 3 according to the change of the pulse time. The interpolator 2 is composed of a unit that divides the original signal by two as shown in the figure, and the number of units from the input to the output can be changed by one unit by the signal from the switcher 11.

As a result, the division ratio (magnification as a whole) between CDs in FIG. 2 can be divided into several stages, and the accuracy of speed control during movement can be increased.

Embodiment 3 FIG. 4 shows a third embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. With this configuration, the second counter 4 and the adder 7 are unnecessary while having the characteristics of the second embodiment.

[0019]

As described above, according to the present invention, the division ratio of the interpolating means is set to the N-th power of 2, and the accuracy of the position detector is impaired by changing the division ratio and shifting the count output. You can increase the moving speed without
It is possible to meet the requirements of high accuracy and high throughput. Further, since the change in magnification is absorbed by the bit shift of the output, it is not necessary for the side receiving this signal to consider the change in magnification.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the embodiment of the present invention.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a third embodiment of the present invention.

FIG. 5 is an explanatory diagram of a conventional technique.

FIG. 6 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

1 Incremental encoder 2 Interpolator (N 2 times) 3 First counter for counting output of interpolator 4 Second counter for counting original signal of encoder output 5 Output register of first counter (N (Bit) 6 Output register of the second counter (the hatched portion is for indicating the length of the entire bit string and does not actually exist) 7 Adder for taking the sum of the first output register and the second output register 8 Output register 9 of pulse counting device 9 Switch for checking the time change rate of pulses and generating a switching signal 10 Switch for deciding whether to add the count result of the first counter to the adder 7 by the signal from the switch 9

Claims (1)

[Claims] 1. A detection means for generating a sine wave signal according to a displacement amount of position information or rotation angle information, an interpolation means for dividing the sine wave to generate a pulse signal, and the interpolation means. The position signal is counted by counting 2 pulses
And a counter for outputting a binary bit string, changing the division ratio of the interpolation means to the Nth power of 2 (N: natural number), and not using the lower bit of the output in synchronization with the change of the division ratio. A pulse counting device characterized in that