JPS62291516A - Rotating encoder - Google Patents

Abstract

PURPOSE:To detect the absolute position of electric source disconnection time, by executing position detection in the entire stroke at the end of operation with a rotating encoder provided with a magnetic circular disc. CONSTITUTION:A magnetic-scale rotating encoder 21 directly connected to a driving electric motor 1 takes records finely divided magnetic division 5 and origin magnetic division 6 on a circular disc 4 mounted on a rotating shaft. The division 5 is detected by magnetic detecting elements 7, 7' and the origin magnetic division detecting element 8 generates a pulse per each revolution of the circular disc 4. Outputs of the elements 7, 7' a rotating direction identifying signal by a rotating direction identifying circuit 9 and control simultaneously addition and subtraction of the origin magnetic division reading-out up-down counter 10 and finely divided magnetic division reading-out up- down counter 11 and the counter 11 counts the absolute rotating angle per each revolution of the rotating shaft and the counter 10 the absolute number of revolutions of the rotating shaft. An arithmetic operation circuit 12 combines counted values of the counters 10, 11 for calculation of the absolute rotation angle of the rotating shaft. By this arrangement, as an integrated battery 15 supplies an electric current to counters 10, 11, elements 7, 7', 8 and circuits 9, 12, the absolute rotating angle can be issued out even if the electric source is disconnected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is attached to an electric motor that drives the working end of a robot or NC machine, and is used to control the rotation speed and rotation angle within one revolution of a final stage drive shaft near the working end. This relates to a high-precision rotary encoder that detects and constantly outputs the absolute rotation angle of a rotating shaft.

Conventional technology When controlling the electric motor of conventional robots and NC machines, a reduction gear is interposed between the shaft end of the motor and the working end, so it is difficult to detect the absolute position of the working end on the motor shaft side. ,
Further, one reducer having the same reduction ratio as the reducer driving the working end is provided to drive the potentiometer, and the output is detected by the potentiometer, or an encoder is provided at the shaft end of the motor to detect the rotation angle within one rotation. Alternatively, detection was performed by combining a code plywood and an encoder or code plate that detects the number of revolutions.

Problems to be Solved by the Invention In the prior art described above, the former employs a mechanical storage method in which the potentiometer is driven via a deceleration mechanism different from the working end drive system to store the absolute position of the working end. Therefore, play in mechanical parts and backlash in gears can cause errors. In addition, in the latter case, it is not only necessary to use two encoders or code plates, but also the detected position information disappears in the event of a power outage or interruption, and when the power is restored, the absolute position is returned to the origin position of the working end. It was necessary to carry out calibration work, which caused a big problem in the operation of the machine.

The present invention was devised as a conventional storage device for the absolute position of the working end, and detects the position of the working end over the entire stroke using one rotary encoder (
In this way, the absolute position of the working end is always detected and stored even in the event of a power outage or power interruption.

Structure of the Invention The rotary encoder of the present invention has a rotating shaft made of a magnetic material.
Two discs are attached concentrically, and the outer circumference of the disc has a set of subdivided magnetic scales equally divided over the circumference, and the inner circumference has a magnetic origin at one location on the circumference. Record the scale,
The former makes it possible to measure the rotation angle within one rotation, and the latter makes it possible to measure the rotational speed of the rotating shaft. Each magnetic scale is detected by a magnetic detection element, such as a magnetoresistive element, which requires extremely low driving power. In detecting the subdivision magnetic scale, two magnetic detection elements are placed on the same circumference at a constant interval so that the phase difference of the output voltage is 90 degrees electrical angle. The output signal of the element is input to a rotational direction discrimination circuit to obtain a rotational direction discrimination signal, and the signal is used to connect a subdivision magnetic scale reading up/down counter connected to a subdivision magnetic scale detection element and an origin magnetic scale detection element. The up-down counter that reads the origin magnetic scale is controlled at the same time, and the subdivided magnetic scale read up-down counter measures the absolute rotation angle during one rotation of the rotating shaft, and the origin magnetic scale read up-down counter measures the absolute rotational speed of the rotating shaft. The calculation circuit calculates and stores the sum of the counts of both up and down counters, but the above counting circuit and calculation circuit are consumed? It is composed of a CMO3 integrated circuit with extremely low L force, and is powered by a built-in encoder battery that is floatingly connected to an external power supply along with the aforementioned magnetic detection element.
The present invention provides a rotary encoder device that constantly outputs the absolute rotation angle of a rotating shaft even during a power outage or power interruption.

Note that the finely divided magnetic scale may use two sets of equally divided magnetic scales in which the inner scale and the outer scale are shifted by y@9 scales, but in this case, the scales of the two magnetic detection probes are as follows. They may be arranged at regular intervals on the same radius so that the phase difference between the output voltages is 90 degrees electrical angle.

Embodiment As shown in Fig. 1, the magnetic scale rotary encoder 2 directly connected to the drive motor 1 is subdivided into the outer peripheral part of a circle &4) from a magnetic material attached concentrically to its rotating shaft 3.
ii Ki scale 5'? ! : The origin magnetic scale 6 is recorded at one location on the inner circumference of the same disk.

The θ11-division Gii scale on the outer circumference is subdivided by a certain amount of 1 A and *! The i'l Mi magnetic scale is detected by two magnetic detection probes I and 1' arranged in opposition to each other, and the output voltages of the respective detection elements have a phase difference of 90 degrees electrical angle.

There is one origin magnetic scale detection element 8 on the inner circumference, and one
Generates one pulse per revolution.

The outputs of the subdivision magnetic scale detection elements 7 and 7' generate a rotation direction discrimination signal by the rotation direction discrimination circuit 9, and simultaneously add/subtract the origin magnetic scale reading up/down counter 10 and the subdivision magnetic scale reading up/down counter 11. The subdivision magnetic scale reading up/down counter counts the absolute rotation angle during one rotation of the rotating shaft, and the origin magnetic scale reading up/down counter counts the absolute rotation number of the rotating shaft. The arithmetic circuit 12 combines the counts of the up/down counters 10 and 11 and calculates the absolute rotation angle of the rotating shaft.

The built-in M15 is rechargeable and supplies power to the up/down counter IL1.11, rotational direction discrimination circuit 9.3 magnetic scale detection probes γ, r', s, and arithmetic circuit, as well as the AC power supply 13 and rectifier. 70-ting connection via 14.

With the above configuration, the built-in battery 15 is always connected to the up/down counter 0.11 and the three magnetic scale detection elements 7, 7'.
, 8, the rotational direction discrimination circuit, and the arithmetic circuit, this rotary encoder device can always output the absolute rotational angle even if it is interrupted during a power outage or power interruption.

Here, if a magnetoresistive element is used as the magnetic scale detection element, 5
Although it is possible to detect the magnetic scale with an applied voltage of 5 Ω and a resistance value of 5 Ω, the current consumption per rope is 1 = 5 ooo = 0.001 A = 1 mA up/down counter 0.11. If a CMOS integrated circuit is used for the rotation direction discrimination circuit and arithmetic circuit, the current output will be 100 μA (0,1
mA) or less, and the consumption of the circuit part can be ignored.

Therefore, if an IAHV (Ni Cd) battery is used as the built-in battery, it can operate even if the external power supply is cut off.

Furthermore, what is shown in Fig. 2 shows the case of recording by subdividing a magnetic disc, and the two magnetic scale detection elements T and 1' have a phase difference of 90 degrees electrical angle between the output voltages. The inner and outer scales are arranged on the same radius of each scale at regular intervals so that the inner and outer scales face each other.

Effects of the Invention The rotary encoder of the present invention has a subdivision magnetic scale and an origin magnetic scale recorded on one magnetic disk, thereby making it possible to replace the conventional rotary speed encoder or code plate and rotation angle encoder or code. Instead of using two boards, it can now be configured with a single rotary encoder, making it extremely compact compared to conventional optical encoders, and reducing gravity consumption. Even when the power is cut off or the power is turned off, the built-in compact battery can record, display, and output the absolute rotation angle of the encoder rotation axis for a long period of time. can. Therefore, this rotary encoder is installed on the rotary shaft of the electric motor, and the rotary encoder is connected to the robot or the robot via the reduction gear.
If you connect it to the working end of a C machine, etc., and set the working end and each zero point of the rotary encoder to match, the working end and ? 4i Unless there is a change in the mechanical connection of the mower9, the rotary encoder will always output the absolute position of the working end over the entire stroke, and the operator will be able to determine the origin of the working end at the start of work or after power is restored. Calibration work such as making adjustments becomes unnecessary.

In addition, as mentioned above, the dud 1/1 encoder has a magnetic scale on a magnetic disc, and compared to conventional optical encoders, it is possible to manufacture ultra-compact, high-resolution rotary encoders. It offers great features that can be realized in NC machines, robots, etc. in an extremely small space.

[Brief explanation of drawings]

Figure 1 shows a counting cycle W: 6 rib block diagram including the one-stroke scale disc and scale detection probe of the rotary encoder of the present invention, and Figure 2 shows a subdivided magnetic scale with a phase difference of 90 degrees. This is an example in which the scale and the outer scale are recorded independently. DESCRIPTION OF SYMBOLS 1... Drive motor, 2... Magnetic scale rotary encoder, 3... Rotating shaft, 4... Same root made of magnetic material, End... Subdivision magnetic scale, 6... Origin magnetic scale, 7
, 7'... Subdivision magnetic scale detection element, 8... Origin magnetic scale detection element, 9... Rotation direction discrimination circuit, 10...
・Up-down counter for origin magnetic scale, 11...
Up-down counter for subdivision magnetic scale, 12...
Arithmetic circuit, 13... AC power supply, 14... Rectifier, 1
5...Internal battery

Claims (1)

[Claims] A disk made of magnetic material is attached concentrically to the rotating shaft,
The outer circumferential portion of the disk has 1 equal parts divided over the circumference.
A set of finely divided magnetic scales or two sets of the same finely divided magnetic scales with the inner and outer scales shifted by 1/4 scale are recorded, and the inner circumference of the disc is also marked with an origin at one location on the circumference. Records the magnetic scale and outputs two magnetic detection elements on the same circumference for one set of finely divided magnetic scales, and on the same radius of each scale for two sets of finely divided magnetic scales. They are arranged at regular intervals so that the voltage phase difference is 90 degrees electrical angle, one magnetic detection element is arranged with respect to the origin magnetic scale, and the output of the two subdivided magnetic detection elements is rotated. A direction discrimination signal is inputted to the direction discrimination circuit to obtain a rotation direction discrimination signal, and the signal is used to detect the subdivision magnetic scale reading up/down counter connected to the subdivision magnetic scale detection element and the origin magnetic scale reading up/down counter connected to the origin magnetic scale detection element. The down counter is controlled at the same time, and the subdivided magnetic scale reading up/down counter counts the absolute rotation angle during one revolution of the rotating shaft, and the origin magnetic scale reading up/down counter counts the absolute rotational speed of the rotating shaft, and the arithmetic circuit calculates both. Calculates and stores the total count value of the up/down counter, and uses a built-in battery floatingly connected to an external power supply to perform subdivision magnetic detection element, origin magnetic detection element, rotation direction discrimination circuit, subdivision magnetic scale reading up/down counter, and origin magnetism. A rotary encoder device that supplies power to a scale reading counter and arithmetic circuit, and constantly outputs the absolute rotation angle of the rotating shaft even during a power outage or power outage.