JPS63243703A - Count-check type detector for angle of rotation - Google Patents

Abstract

PURPOSE:To prevent the accumulation of count errors by a method wherein a count value of a pulse signal for detecting a rotation angle is subjected to division, the residual is calculated and compared with a value set beforehand, and whether a counter value is normal is checked up on the basis of the result of the comparison. CONSTITUTION:During the detection of a rotation angle, a count value of a pulse counter 6 is divided by a prescribed pulse number by a divider 8 and the residual is calculated every time when a Z-pulse signal from a pulse encoder 3 is outputted. When there is no count error, a count value obtained by counting in the counter 6 is due to be integral times as large as the prescribed pulse number, and the residual of the calculation should be zero. When there is the count error, however, the residual of calculation is a value other than zero. Accordingly, the residual produced in calculation by the divider 8 is compared in a comparator 9 with a value set by a setting unit 9a, and based on the difference between them, the result of the decision as to whether the counter value is normal is outputted from a decision unit 10.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device that detects the rotation angle of each rotating shaft in an NC control device, an industrial robot, etc. as a count value of a pulse signal from a pulse generator. In particular, the present invention relates to a count check type rotation angle detection device that is capable of checking the count value.

[Prior Art] Generally, when controlling an NC control device, an industrial robot, etc., a detection device is required to detect the rotation angle of each rotating shaft of the arm or the like with high precision.

Two types of rotation angle detection devices include an absolute type that connects a potentiometer or resolver to the rotation axis to detect the absolute angle, and another type that connects a pulse generator to the rotation axis and receives pulse signals from the pulse generator. There is an incremental type that detects the rotation angle by counting.

Absolute type detection devices detect absolute angles, so even if there is a power outage, the original detected value can be obtained immediately after the power is restored. However, incremental type detection devices are simpler and It is more commonly used because it has a low cost structure and a small number of control wires.

As this rotation angle detection device, there is conventionally one shown in FIGS. 2 and 3. In FIGS. 2 and 3, 1 is an arm of an industrial robot or the like, 2 is a motor that rotationally drives the arm 1 via a speed reducer (not shown), and 3 is a pulse encoder (PE) as a pulse generator. As shown in FIG. 4, this pulse encoder 3 is coupled to the rotating shaft of the motor 2, and as the motor 2 (arm 1) rotates, the pulse encoder 3
Z for setting the origin every one rotation of (pulse encoder 3)
A and B for outputting pulse signals and detecting rotation angle
It outputs a pulse signal. Here, the A and B pulse signals are output with a phase difference of 90', and these A and B pulse signals are output with a phase difference of 90'.
, B pulse signals are detected.

Further, 4 is a dog fixed to the arm 1, 5 is a limit switch arranged on the fixed side and is turned on and off by the dog 4 to detect that the arm 1 is in its original position, and 6 is a signal from the pulse encoder 3. A pulse counter 7 counts the number of A or B pulse signals and outputs the count value as a rotation angle, and 7 is a zero signal generator as an origin setter.

This zero signal generator 7 receives O from the limit switch 5.
This is for setting the origin of the pulse counter 6 in response to the N and OFF signals and the Z pulse signal from the pulse encoder 3.

With the above configuration, when detecting the rotation angle, when the arm 1 starts moving from its original position, as shown in FIG.
Pulse encoder 3 to Z, A.

As soon as the B pulse signal begins to be output, the limit switch 5 turns from ON to OFF. Then, after this limit switch 5 is turned OFF, the point in time when the Z pulse signal is first input to the zero signal generator 7 is set as the origin.
Zero signal generator 7 outputs a clear signal that resets pulse counter 6 at that point.

Thereafter, the pulse counter 6 determines the rotation direction based on the A and B pulse signals inputted from the pulse encoder 3, and counts up or down the A or B pulse signal depending on whether the rotation direction is forward or backward.

In this way, the count value counted by the pulse counter 6 is output as the rotation angle to be detected.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional rotation angle detection device, A.
Since the counter value corresponding to the rotation angle is obtained by counting up or down the B pulse signal, the count value of the pulse counter 6 may deviate from the normal value due to noise or other causes, resulting in a counting error.
This may cause misalignment of control devices and industrial robots.

This possibility can be made almost non-problematic by taking noise countermeasures, but in the unlikely event that a counting error occurs, there is no way to detect the error, so the counting error will accumulate. This may lead to a runaway situation.

The present invention aims to solve these problems by making it possible to check the accuracy of the pulse counter, thereby preventing the accumulation of counting errors, and improving the reliability of rotation angle detection accuracy. It is an object of the present invention to provide an improved count check type rotation angle detection device.

[Means for solving the problem] Therefore, the count check type rotation angle detection device of the present invention uses a pulse counter to count the rotation angle detection pulse signal every time the origin setting pulse signal is output from the pulse generator. A calculating means for calculating a remainder by dividing a value by a predetermined number of pulses, a comparing means for comparing the calculated remainder with a preset value, and checking the count value by the pulse counter based on the comparison result. A determination means is provided.

[Function] In the count check type rotation angle detection device of the present invention described above, the count value obtained by counting the rotation angle detection pulse signal by the pulse counter is as follows.

It is checked as follows. That is, each time the pulse signal for setting the origin is output from the pulse generator, the count value of the pulse signal for rotation angle detection by the pulse counter is divided by a predetermined number of pulses in the calculation means, and the remainder is calculated and compared. The means compares the remainder with a preset value, and then, based on the comparison result, the determining means checks whether the counter value of the pulse counter is normal.

[Embodiments of the Invention] Hereinafter, a count check type rotation angle detection device as an embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram thereof, and in this FIG. Since the same parts indicate the same parts, the explanation thereof will be omitted.

In FIG. 1, 8 is a divider as calculation means, 9 is a comparator as comparison means, 9a is a setting device, and 10 is a judge as judgment means. Each time a pulse signal is received, the count value of the A and B pulse signals by the pulse counter 6 is divided by a predetermined number of pulses to calculate the remainder. Here, the predetermined number of pulses is determined by the pulse encoder 3 because the Z pulse signal is output for each rotation of the pulse encoder 3.
This is the number of pulses of the A and B pulse signals that should be output during one rotation of the Z pulse signal (within the output interval of the Z pulse signal).

Further, the comparator 9 compares the remainder calculated by the divider 8 with a set value inputted in advance by the setter 9, and outputs the difference. 1
0 is for checking whether the counter value by the pulse counter 6 is normal or abnormal, depending on the difference between the comparison result from the comparator 9 and the set value.

In this embodiment, the pulse counter 6 is configured as a 16-bit binary counter that outputs the counter value in binary, and the Z pulse signal from the pulse encoder 3 is used only for setting the origin. It is also used as a timing signal for divider 8 and comparator 9.

Since the count check type rotation angle detection device as an embodiment of the present invention is configured as described above, the pulse counter 3. Limit switch5. The rotation angle detection operation by the pulse counter 6, zero signal generator 7, etc. is performed in exactly the same manner as in the conventional system. On the other hand, during rotation angle detection,
The Z pulse signal from the pulse encoder 3 is used as a timing signal, and each time this Z pulse signal is output, the counter value of the pulse counter 6 at that time is input to the divider 8.
Then, the pulse is divided by the predetermined number of pulses mentioned above (for example, 1000 pulses) and the remainder is calculated.

If there is no counting error, the count value counted by the pulse counter 6 should be an integral multiple of the predetermined number of pulses, so the calculated remainder should be zero. If so, the remainder will be a non-zero value. The present invention uses this to check the count value, and the remainder calculated by the divider 8 is sent to the comparator 9.

It is compared with the setting value set by the setting device 9a, and based on the difference, the judgment device 10 outputs a judgment result as to whether or not the counter value is normal. Here, the output signal of the determination result from the determiner 1o may be outputted to an alarm device or the like so that an abnormality in the counter value can be reported to an operator or the like by the alarm device or the like.

Note that since the Z pulse signal output from the pulse encoder 3 generally has a wider pulse width than the A and B pulse signals, it is unstable in timing with respect to the least significant bit output from the pulse counter 6. Therefore, the lowest 1 and 2
It is desirable to ignore the beep 1-, so setter 9
The setting value a may be exactly 0, but it has a range of -2 to +2, for example.

Also, when inputting the clear signal to the pulse counter 6,
If the pulse counter 6 is not reset to zero but is given an initial value, the setting device 9
Determine the setting value using a.

As described above, according to this embodiment, the count value in the pulse counter 6 can be checked from the remainder calculated by the divider 8, and the accumulation of counting errors is reliably prevented, and the rotation of the robot arm, etc. It is possible to prevent the member from running out of control, and the reliability of rotation angle detection accuracy is greatly improved.

In addition, in recent years, arm 1 of industrial robots (see Figure 2)
In order to omit the origin adjustment operations such as 1. As in this embodiment, the divider 8. By providing the comparator 92, judger 10, etc., it is possible to eliminate concerns (such as instantaneous power outage or malfunction of backup power supply, etc.) under conditions where it is difficult for operators to perform monitoring, such as at night. There are some advantages to doing so.

In the above embodiment, the pulse encoder 3 is used as the pulse generator, but the resolver is connected to the motor 2 (second
(see figure) and connect the output of the resolver to R-P (resolver
A pulse converter that performs pulse conversion may also be used, and the same effects as in the above embodiment can be obtained.

Further, in the above embodiment, the divider 8 is separately provided as a calculation means, but the divider 8 can be implemented by providing this function to a calculation unit for controlling an NC control device or an industrial robot, etc. May be omitted.

Furthermore, in the above embodiment, 1000 pulses corresponding to one rotation of the pulse encoder 3 are used for division as the predetermined number of pulses, but the predetermined number of pulses may be a factor such as 500 pulses or 200 pulses; in this case, , the settings WII 9a can be simplified.

[Effects of the Invention] As detailed above, according to the count check type rotation angle detection device of the present invention, the calculation means, the comparison means, and the determination means are provided, and the remainder of the counter value of the pulse counter calculated by the calculation means is Since the configuration is configured such that the same count value can be checked from the beginning, it is possible to reliably prevent the accumulation of counting errors, prevent the rotating member from running out of control, and significantly improve the reliability of rotation angle detection accuracy.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a count check type rotation angle detection device as an embodiment of the present invention, Fig. 2-3 shows a conventional rotation angle detection device, and Fig. 2 is a perspective view thereof. FIG. 3 is a block diagram thereof, and FIG. 4 is a timing chart 1 for explaining the pulse signal output from the pulse encoder and the origin setting means. In the figure, 1-arm as a rotating member, 2-motor, 3-pulse encoder (PE), 4-dog, 5-limit switch, 6--pulse counter, 7--
Zero signal generator as origin setter, 8-Divider as calculation means, 9...-Comparator as comparison means, 9a-
Setting device, 10--Determining device as determining means. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A pulse generator that outputs a pulse signal for setting the origin at each predetermined rotation angle as the rotating member rotates, and outputs a pulse signal for detecting the rotation angle a predetermined number of pulses within an output interval of the pulse signal for setting the origin. , a pulse counter that counts the rotation angle detection pulse signal from the pulse generator and outputs the count value as the rotation angle of the rotating member; and a pulse counter that receives the origin setting pulse signal and resets the pulse counter. a rotation angle detection device comprising an origin setting device, a calculation means for calculating a remainder by dividing the count value counted by the pulse counter by a predetermined number of pulses each time the origin setting pulse signal is output; A comparison means for comparing the remainder calculated by the calculation means with a preset value, and a determination means for checking the count value of the pulse counter based on the comparison result by the comparison means. Count check type rotation angle detection device.