Encoder device

Abstract

To obtain highly reliable multi-rotation information.SOLUTION: An encoder device includes: an optical detection unit (140) that optically detects rotation of a rotating disk (120) and generates an optical rotation detection signal; a magnetic detection unit (150) that magnetically detects rotation of the rotating disk and generates a magnetic rotation detection signal; and an encoder processing unit (170) that processes the optical rotation detection signal and the magnetic rotation detection signal to generate multi-rotation information. The encoder processing unit (170) generates the multi-rotation information based on at least one of the optical rotation detection signal and the magnetic rotation detection signal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an encoder device, and more particularly to an encoder device capable of obtaining highly reliable multi-rotation information.

Background Art

[0002] As encoders for detecting rotation, there are an optical encoder that detects optical information provided on a rotating disk by an optical detection unit, and a magnetic encoder that detects magnetic information provided on a rotating disk by a magnetic detection unit. There is also an encoder device that has both an optical encoder and a magnetic encoder. Encoder devices that combine a plurality of different sensors in this way have been proposed in Patent Documents 1 and 2.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 discloses an encoder device having a resolver that requires power to detect an angle, a magnetic sensor that detects rotation without power, and a switch that switches between the resolver and the magnetic sensor. In this encoder device, it is shown that according to the power supply state, one of a resolver and a magnetic sensor is switched and used by a switching switch. In the case of this encoder device, there are problems that an operation of switching the switch is necessary, and the resolver and the magnetic sensor are independent and not interlocked or coordinated. And, in the case of this encoder device, one of the resolver and the magnetic sensor is selected according to the power supply state, and consideration has not been given to obtaining highly reliable multi-rotation information.

[0005] Patent Document 2 discloses an encoder device that uses a first encoder for detecting the rotation of a rotating disk that rotates at a constant speed together with a rotating body, and a second encoder for detecting the rotation of a rotating disk that rotates at a low speed of about 1 / 100 to 1 / 1000 via a speed reduction mechanism. In this encoder device, the first encoder is responsible for angle information, and the second encoder is responsible for rotation information. In the case of this encoder device, since a speed reduction mechanism is used, there is a problem that the mechanical configuration and calculation become complicated. And, in the case of this encoder device, it is intended to obtain angle information and multi-rotation information, and no consideration has been given to obtaining highly reliable multi-rotation information.

[0006] In Patent Document 1 and Patent Document 2, it is possible to obtain multi-rotation information, but it has been difficult to surely obtain multi-rotation information due to various factors such as a sudden change in the rotation speed, poor power supply, and foreign matter intrusion. Therefore, in an encoder device, it has been desired to obtain highly reliable multi-rotation information. An object of the present invention is to provide an encoder device capable of obtaining highly reliable multi-rotation information.

Means for Solving the Problems

[0007] The encoder device according to the present invention optically detects the rotation of a rotating disk, Including multi-rotation information an optical detection unit that generates an optical rotation detection signal, magnetically detects the rotation of the rotating disk, Including multi-rotation informationA magnetic detection unit that generates a magnetic rotation detection signal, and an encoder processing unit that processes an optical rotation detection signal and the magnetic rotation detection signal to generate multi-rotation information, wherein the encoder processing unit generates multi-rotation information based on at least one of the optical rotation detection signal and the magnetic rotation detection signal.

[0008] In the encoder device according to the present invention, the encoder processing unit generates multi-rotation information based on the optical rotation detection signal when the rotation speed is less than a predetermined rotation speed, and generates multi-rotation information based on the magnetic rotation detection signal when the rotation speed is equal to or greater than the predetermined rotation speed. In the encoder device according to the present invention, The predetermined rotational speed is determined within a range where the occurrence frequency of errors in the optical detection unit and the occurrence frequency of errors in the magnetic detection unit are both low, referring to the rotational speed at the time of detection by the optical detection unit and the occurrence frequency of errors, and the rotational speed at the time of detection by the magnetic detection unit and the occurrence frequency of errors. In the encoder device according to the present invention, the encoder processing unit generates multi-rotation information based on any one of the optical rotation detection signal and the magnetic rotation detection signal that exists.

[0009] In the encoder device according to the present invention, the encoder processing unit generates optical rotation information based on the optical rotation detection signal, generates magnetic rotation information based on the magnetic rotation detection signal, determines whether the optical rotation information and the magnetic rotation information are each normal, and generates multi-rotation information based on at least one of the optical rotation information and the magnetic rotation information determined to be normal. Here, when neither the optical rotation information nor the magnetic rotation information exists, when both the optical rotation information and the magnetic rotation information are not normal, and when one of the optical rotation information and the magnetic rotation information does not exist and the other exists but is not normal, the encoder processing unit issues error information.

Advantages of the Invention

[0010] According to the present invention, the rotation of the rotating disk is optically detected to generate an optical rotation detection signal, the rotation of the rotating disk is magnetically detected to generate a magnetic rotation detection signal, and multi-rotation information is generated based on at least one of the optical rotation detection signal and the magnetic rotation detection signal. Therefore, an encoder device capable of obtaining highly reliable multi-rotation information can be provided.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the encoder device of the present invention will be described with reference to the drawings. In each figure, the same parts are denoted by the same reference numerals.

[0013] Embodiment 1. First, the basic configuration of the encoder device 100 in Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a configuration diagram showing the circuit configuration of the encoder device 100 in Embodiment 1. FIG. 2 is a perspective view showing the optical detection unit 140 and the magnetic detection unit 150 of the encoder device 100 in Embodiment 1 together with the rotating body 1 and the rotating disk 120.

[0014] [Configuration of Encoder Device 100] In FIG. 1, the encoder device 100 mainly includes a rotating disk 120, an optical detection unit 140, a magnetic detection unit 150, and an encoder processing unit 170. This encoder device 100 generates multi-rotation information corresponding to the rotation of the rotating body 1 based on the optical detection result and the magnetic detection result.

[0015] The rotating disk 120 is connected to the rotating body 1 via the rotating shaft 10 and rotates at the same rotational speed as the rotating body 1. The rotating shaft 10 is connected to a driven body (not shown). As shown in FIG. 2, optical information 130A and magnetic information 130B are formed on the rotating disk 120. The rotating body 1 is driven to rotate by a controller (not shown). FIG. 2 shows a specific example in which there is one rotating disk 120, but it is also possible to use two rotating disks 120 for the optical information 130A and the magnetic information 130B.

[0016] The optical information 130A is formed as annular optical information on the rotating disk 120, and may be formed either as a transmission slit or a reflection pattern. The optical information 130A may be either dedicated information for obtaining multi-rotation information or shared information for obtaining both angular information within one rotation and multi-rotation information. The magnetic information 130B is magnetized in any one of the radial direction, the circumferential direction, or the axial direction, and is magnetic information for obtaining multi-rotation information. Here, the direction along the axis of the rotating disk 120 is defined as the "axial direction", the direction along the radius of the rotating disk 120 is defined as the "radial direction", and the direction along the rotation direction of the rotating disk 120 is defined as the "circumferential direction". FIG. 2 schematically shows a state in which an N pole is formed at one end in the radial direction and an S pole is formed at the other end in the radial direction.

[0017] The optical detection unit 140 detects the optical information 130A formed on the rotating disk 120 as the light and dark of light by light transmission or reflection to generate an optical rotation detection signal, and supplies the generated optical rotation detection signal to the encoder processing unit 170. The optical detection unit 140 is a specific example of reading the optical information 130A formed as a slit on the rotating disk 120, and has a light emitting unit 141 and a light receiving unit 142 so as to sandwich the rotating disk 120.

[0018] The light receiving unit 142 is composed of, for example, a light receiving element group composed of a set of four light receiving elements. Here, the four light receiving elements constituting the light receiving element group are assigned a+, a-, b+, b-. By adding and subtracting the signals from each of these light receiving elements a+, a-, b+, b-, two-phase optical rotation detection signals having different phases are generated, and the generated two-phase optical rotation detection signals are supplied to the encoder processing unit 170.

[0019] The magnetic detection unit 150 detects the magnetic information 130B formed on the rotating disk 120 as a change in the magnetic field by the magnetic sensor 151, generates a magnetic rotation detection signal from the detected change in the magnetic field, and supplies the generated magnetic rotation detection signal to the encoder processing unit 170.

[0020] The encoder processing unit 170 is provided with a rotation detection unit 171, a presence confirmation unit 172, a determination unit 173, an information update unit 174, an error detection unit 175, and a communication unit 176. The encoder processing unit 170 is driven by a normal operation power supply during power-on and is driven by a backup power supply such as a battery during a power outage. The driving power supply is supplied from the encoder processing unit 170 to the optical detection unit 140.

[0021] The rotation detection unit 171 generates optical rotation information indicating one rotation of the rotating disk 120 based on the optical rotation detection signal from the optical detection unit 140, and generates magnetic rotation information indicating one rotation of the rotating disk 120 based on the magnetic rotation detection signal from the magnetic detection unit 150. The rotation detection unit 171 supplies the generated optical rotation information and magnetic rotation information to the presence confirmation unit 172 and the determination unit 173.

[0022] The presence confirmation unit 172 confirms the presence of each of the optical rotation information and the magnetic rotation information, and generates non-existence information when one of the optical rotation information and the magnetic rotation information does not exist, and when both the optical rotation information and the magnetic rotation information do not exist, and supplies the non-existence information to the error detection unit 175.

[0023] The determination unit 173 determines whether the optical rotation information and the magnetic rotation information are normal, and supplies determination information indicating abnormality to the error detection unit 175 when both the optical rotation information and the magnetic rotation information are not normal. Note that the determination unit 173 determines that the non-existent one is also abnormal when at least one of the optical rotation information and the magnetic rotation information does not exist. On the other hand, when the determination unit 173 determines that at least one of the optical rotation information and the magnetic rotation information is normal, the determination unit 173 supplies the information update unit 174 with the one determined to be normal among the optical rotation information and the magnetic rotation information as the rotation information.

[0024] Based on the rotation information determined to be normal by the determination unit 173, the information update unit 174 increments the stored cumulative rotation value (hereinafter referred to as the rotation cumulative value), and supplies the incremented new rotation cumulative value to the communication unit 176 as the multi-rotation information.

[0025] Receiving the non-existence information from the existence confirmation unit 172 and the determination information from the determination unit 173, when any of the following cases applies: neither the optical rotation information nor the magnetic rotation information exists; both the optical rotation information and the magnetic rotation information are not normal; one of the optical rotation information and the magnetic rotation information does not exist while the other exists but is not normal, the error detection unit 175 supplies error information to the communication unit 176.

[0026] The communication unit 176 transmits the multi-rotation information from the information update unit 174 to an external controller at a predetermined fixed period. Further, the communication unit 176 transmits the error information generated by the error detection unit 175 to the external controller.

[0027] [Operation of the Encoder Device 100] Next, with reference to FIG. 3, the process for the encoder device 100 to detect the optical information 130A and the magnetic information 130B of the rotating disk 120 to obtain highly reliable multi-rotation information will be described. FIG. 3 is a flowchart showing the processing procedure of the encoder device 100 in the first embodiment.

[0028] As a premise, the rotating disk 120 on which the optical information 130A and the magnetic information 130B are formed is connected to the rotating body 1 via the rotating shaft 10 and rotates at the same speed as the rotating body 1. The rotating body 1 is driven by a controller (not shown) and drives a driven body (not shown) through the rotating shaft 10.

[0029] In step S101A, the optical detection unit 140 irradiates the optical information 130A of the rotating disk 120 with light from the light emitting unit 141, and receives the transmitted light that has transmitted the optical information 130A in accordance with the rotation of the rotating disk 120 by the light receiving unit 142 to generate an optical rotation detection signal. The optical detection unit 140 supplies the generated optical rotation detection signal to the encoder processing unit 170. After this, the process proceeds to step S102A. In step S101B, the magnetic detection unit 150 detects the magnetic information 130B formed on the rotating disk 120 as a change in the magnetic field according to the rotation of the rotating disk 120 by the magnetic sensor 151, and generates a magnetic rotation detection signal from the detected change in the magnetic field. The magnetic detection unit 150 supplies the generated magnetic rotation detection signal to the encoder processing unit 170. After this, the process proceeds to step S102B.

[0030] The encoder processing unit 170 is supplied with the optical rotation detection signal and the magnetic rotation detection signal, and generates highly reliable multi-rotation information as follows.

[0031] In step S102A, the rotation detection unit 171 processes the optical rotation detection signal from the optical detection unit 140 to generate optical rotation information. In step S102B, the rotation detection unit 171 processes the magnetic rotation detection signal from the magnetic detection unit 150 to generate magnetic rotation information. As will be described later, the rotation detection unit 171 may generate only at least one of the optical rotation detection signal and the magnetic rotation detection signal according to the situation.

[0032] Since the magnetic detection unit 150 detects the magnetic information 130B as a change in the magnetic field, the level of the detection signal decreases as the rotation speed of the rotating disk 120 decreases. However, it can easily follow the change in the magnetic field during sudden acceleration or high-speed rotation of the rotating disk 120. On the other hand, since the optical detection unit 140 optically detects the optical information 130A by transmission or reflection, it can perform stable reading during low-speed rotation of the rotating disk 120. However, during sudden acceleration or high-speed rotation of the rotating disk 120, reading may exceed adjacent quadrants, which may cause difficulties in continuing the detection.

[0033] Therefore, the rotation detection unit 171 may determine the rotation speed of the rotation disk 120 based on either the magnetic rotation detection signal or the optical rotation detection signal, and then stop generating magnetic rotation information and generate optical rotation information when the rotation speed is lower than a predetermined rotation speed, and stop generating optical rotation information and generate magnetic rotation information when the rotation speed is higher than the predetermined rotation speed. Here, it is desirable to set the "predetermined rotation speed" near the middle of the overlapping range between the rotation speed that can be stably detected by the optical detection unit 140 and the rotation speed that can be stably detected by the magnetic detection unit 150. Also, the "predetermined rotation speed" may be determined within a range where the occurrence frequencies of errors are both low with reference to the rotation speed and the occurrence frequency of errors during detection by the optical detection unit 140, and the rotation speed and the occurrence frequency of errors during detection by the magnetic detection unit 150. When the generation of the optical rotation detection signal in the optical detection unit 140 and the generation of the magnetic rotation detection signal in the magnetic detection unit 150 can be stably performed, the rotation detection unit 171 generates both magnetic rotation information and optical rotation information. After that, the process proceeds to step S103.

[0034] In step S103, the presence confirmation unit 172 confirms the presence of the optical rotation information and the magnetic rotation information. When either the optical rotation information or the magnetic rotation information does not exist, or when neither the optical rotation information nor the magnetic rotation information exists, the presence confirmation unit 172 generates non - existence information. Here, "does not exist" includes not only the case where the non - existence period is continuous, but also the state where it is momentarily interrupted or an error occurs. When the error - correction code can eliminate the interruption or the error, it can be treated as existing. The presence confirmation unit 172 can also determine whether it exists or not based on the error rate calculated digitally as the confirmation of existence. When the presence confirmation unit 172 generates non - existence information, it supplies the generated non - existence information to the error detection unit 175. After that, the process proceeds to step S104.

[0035] In step S104, the determination unit 173 determines whether the optical rotation information and the magnetic rotation information from the rotation detection unit 171 are normal or not. For example, the determination unit 173 compares the optical rotation information with the rotation cumulative value stored in the information update unit 174. If the determination formula "optical rotation information = rotation cumulative value + 1" is satisfied, it determines that the optical rotation information is normal; otherwise, it determines that the optical rotation information is abnormal. Similarly, the determination unit 173 compares the magnetic rotation information with the rotation cumulative value stored in the information update unit 174. If the determination formula "magnetic rotation information = rotation cumulative value + 1" is satisfied, it determines that the magnetic rotation information is normal; otherwise, it determines that the magnetic rotation information is abnormal.

[0036] When the determination unit 173 determines that both the optical rotation information and the magnetic rotation information are abnormal, it does not supply the optical rotation information and the magnetic rotation information to the information update unit 174, but supplies the determination information to the error detection unit 175. After that, the process proceeds to step S105.

[0037] In step S105, the error detection unit 175 performs error detection based on the non-existence information from the existence confirmation unit 172 and the determination information from the determination unit 173. When an error is detected, it supplies the error information to the communication unit 176.

[0038] When any of the following conditions is met, the error detection unit 175 generates error information as if an error has been detected and supplies the generated error information to the communication unit 176. · Neither the optical rotation information nor the magnetic rotation information exists. · Both the optical rotation information and the magnetic rotation information are abnormal. · One of the optical rotation information and the magnetic rotation information does not exist, while the other exists but is abnormal. Therefore, if at least one of the optical rotation information and the magnetic rotation information is normal, the error detection unit 175 does not generate error information.

[0039] In step S105, when the error detection unit 175 generates error information, the process proceeds to step S106. In step S106, the communication unit 176 transmits the error information supplied from the error detection unit 175 by including it in communication directed to an external controller or the like. After this, the process proceeds to step S110.

[0040] When it is determined by the determination unit 173 that at least one of the optical rotation information and the magnetic rotation information from the rotation detection unit 171 is normal, and when the error detection unit 175 does not generate error information in step S105, the process proceeds to step S107. In step S107, the determination unit 173 outputs as rotation information that which is determined to be normal among the optical rotation information and the magnetic rotation information, and supplies it to the information update unit 174. After this, the process proceeds to step S108.

[0041] In step S108, the information update unit 174 increments the rotation cumulative value stored until then by the rotation information supplied from the determination unit 173. The information update unit 174 supplies the incremented new rotation cumulative value as multi-rotation information to the communication unit 176. After this, the process proceeds to step S109.

[0042] In step S109, the communication unit 176 transmits the multi-rotation information supplied from the information update unit 174 toward an external controller or the like. After this, the process proceeds to step S110.

[0043] In step S110, when the rotation of the rotation disk 120 continues, the encoder device 100 returns the process to step S101 and repeats the series of processes described above. On the other hand, when the rotation of the rotation disk 120 stops, the encoder device 100 ends the process.

[0044] [Features of the operation of the encoder device 100] Here, the features of the operation of the encoder device 100 will be described in detail. The encoder processing unit 170 in Embodiment 1 generates multi-rotation information based on at least one of an optical rotation detection signal and a magnetic rotation detection signal obtained by detecting the rotation of the rotating disk 120. That is, in the encoder processing unit 170 of Embodiment 1, rotation information is generated based on at least one of the optical rotation information generated from the optical rotation detection signal and the magnetic rotation information generated from the magnetic rotation detection signal, and the rotation cumulative value is updated with the rotation information to generate multi-rotation information.

[0045] When foreign matter enters near the optical information 130A of the rotating disk 120, the optical detection unit 140 is affected by the entry of the foreign matter and it becomes difficult to detect the optical information 130A. On the other hand, even if foreign matter enters near the magnetic information 130B of the rotating disk 120, the magnetic detection unit 150 can continue to detect the magnetic information 130B due to the change in the magnetic field. In such a case, multi-rotation information can be generated using the magnetic rotation detection signal from the magnetic detection unit 150.

[0046] The optical detection unit 140 may be affected by power supply problems such as momentary power interruption or voltage fluctuation, making it difficult to detect the optical information 130A. On the other hand, the magnetic detection unit 150 configured in a non-powered manner can continue to detect the magnetic information 130B without being affected by power supply problems. In such a case, multi-rotation information can be generated using the magnetic rotation detection signal from the magnetic detection unit 150.

[0047] When an external magnetic force acts on the optical detection unit 140 and the magnetic detection unit 150, or when a magnetic body exists on the rotating disk 120, it becomes difficult for the magnetic detection unit 150 to continue detecting the magnetic information 130B. On the other hand, the optical detection unit 140 can continue to detect the optical information 130A without being affected by the magnetic force. In such a case, multi-rotation information can be generated using the optical rotation detection signal from the optical detection unit 140.

[0048] When noise is externally mixed into the optical detection unit 140 and the magnetic detection unit 150, there is a possibility that either the optical detection unit 140 or the magnetic detection unit 150 with different detection methods is not affected by the noise. Therefore, multi-rotation information can be generated using the rotation detection signal from either the optical detection unit 140 or the magnetic detection unit 150.

[0049] The magnetic detection unit 150 causes a decrease in the amplitude of the detection signal during low-speed rotation, but can easily follow changes in the magnetic field during rapid acceleration or high-speed rotation. On the other hand, the optical detection unit 140 is likely to cause reading failures during rapid acceleration or high-speed rotation, but can perform stable reading during low-speed rotation. For this reason, multi-rotation information can be generated using the magnetic rotation detection signal from the magnetic detection unit 150 during low-speed rotation below a predetermined rotation speed, and multi-rotation information can be generated using the optical rotation detection signal from the optical detection unit 140 during high-speed rotation exceeding the predetermined rotation speed. In this case, it is desirable to generate multi-rotation information using both the optical rotation detection signal and the magnetic rotation detection signal near the predetermined rotation speed.

[0050] As described above, the encoder processing unit 170 according to the first embodiment uses rotation detection signals with different detection methods, such as the optical rotation detection signal obtained from the optical detection unit 140 and the magnetic rotation detection signal obtained from the magnetic detection unit 150, so that multi-rotation information can be generated using the rotation detection signal from at least one of them in various situations. Therefore, it is possible to obtain highly reliable multi-rotation information compared to a redundant system method in which a plurality of sensors of the same type are provided.

[0051] [Other Embodiments] In addition to making the optical information 130A a dedicated pattern for obtaining multi-rotation information, it can be a pattern corresponding to both obtaining angle information regarding the angle within one rotation and obtaining multi-rotation information. In this case, by applying Embodiment 1 to an existing encoder device that optically obtains angle information and magnetically obtains multi-rotation information, it becomes possible to obtain highly reliable multi-rotation information without adding mechanical parts and without changing the device size. In Embodiment 1, the single rotation disk 120 may be constituted by two disks, namely, a first rotation disk on which the optical information 130A is formed and a second rotation disk on which the magnetic information 130B is formed. In this case, since the first rotation disk and the second rotation disk rotate at a constant speed together with the rotation axis 10, there is no need to modify the encoder processing unit 170.

[0052] [Effects of the Embodiment] The encoder device 100 of Embodiment 1 includes an optical detection unit 140 that optically detects the rotation of the rotation disk and generates an optical rotation detection signal, a magnetic detection unit 150 that magnetically detects the rotation of the rotation disk and generates a magnetic rotation detection signal, and an encoder processing unit 170 that processes the optical rotation detection signal and the magnetic rotation detection signal and generates multi-rotation information. The encoder processing unit 170 generates multi-rotation information based on at least one of the optical rotation detection signal and the magnetic rotation detection signal, so that it can generate multi-rotation information without being affected by the intrusion of foreign matter, magnetic force, or noise, power supply failure, or change in the rotation speed of the rotation disk 120, and it becomes possible to obtain highly reliable multi-rotation information.

[0053] In the encoder device 100 of Embodiment 1, the encoder processing unit 170 generates multi-rotation information based on the optical rotation detection signal when the rotation speed is less than a predetermined rotation speed, and generates multi-rotation information based on the magnetic rotation detection signal when the rotation speed is greater than or equal to the predetermined rotation speed. By doing so, it is possible to generate normal multi-rotation information in respective suitable situations of the optical detection unit 140 and the magnetic detection unit 150, and it becomes possible to obtain highly reliable multi-rotation information.

[0054] In the encoder device 100 according to the first embodiment, the encoder processing unit 170 generates multi-rotation information based on either the optical rotation detection signal or the magnetic rotation detection signal that exists, so that it is possible to obtain highly reliable multi-rotation information without omission.

[0055] In the encoder device 100 according to the first embodiment, the encoder processing unit 170 generates optical rotation information based on the optical rotation detection signal, generates magnetic rotation information based on the magnetic rotation detection signal, determines whether the optical rotation information and the magnetic rotation information are normal respectively, and generates multi-rotation information based on at least one of them determined to be normal. Therefore, it is possible to generate multi-rotation information without being affected by the intrusion of foreign matter, magnetic force, or noise, poor power supply, or change in the rotation speed of the rotating disk 120, and it is possible to obtain highly reliable multi-rotation information.

[0056] In the encoder device 100 according to the first embodiment, when neither the optical rotation information nor the magnetic rotation information exists, or when both the optical rotation information and the magnetic rotation information are not normal, the encoder processing unit 170 transmits error information to the controller. Therefore, it is possible to clarify the situation where multi-rotation information cannot be obtained.

Description of Reference Numerals

[0057] 1 Rotating body, 10 Rotating shaft, 100 Encoder device, 120 Rotating disk, 130A Optical information, 130B Magnetic information, 140 Optical detection unit, 141 Light emitting unit, 142 Light receiving unit, 150 Magnetic detection unit, 151 Magnetic sensor, 170 Encoder processing unit, 171 Rotation detection unit, 172 Existence confirmation unit, 173 Determination unit, 174 Information update unit, 175 Error detection unit, 176 Communication unit.

Claims

1. An optical detection unit (140) that optically detects the rotation of a rotating disk (120) and generates an optical rotation detection signal including multi-rotation information; A magnetic detection unit (150) that magnetically detects the rotation of the rotating disk (120) and generates a magnetic rotation detection signal including the multi-rotation information; An encoder processing unit (170) that processes the optical rotation detection signal and the magnetic rotation detection signal to generate the multi-rotation information, wherein the encoder processing unit (170) When generating the multi-rotation information based on either the optical rotation detection signal or the magnetic rotation detection signal, After obtaining the rotation speed of the rotating disk (120) by either the magnetic rotation detection signal or the optical rotation detection signal, Generates the multi-rotation information based on the optical rotation detection signal when the rotation speed is less than a predetermined rotation speed, Generates the multi-rotation information based on the magnetic rotation detection signal when the rotation speed is equal to or greater than the predetermined rotation speed, Encoder device.

2. The predetermined rotation speed refers to the rotation speed and error occurrence frequency during detection by the optical detection unit (140), and the rotation speed and error occurrence frequency during detection by the magnetic detection unit (150), and is determined within a range where the error occurrence frequency in the optical detection unit (140) and the error occurrence frequency in the magnetic detection unit (150) are both low. The encoder device according to claim 1.

3. The encoder processing unit (170) generates the multi-rotation information based on any one of the optical rotation detection signal and the magnetic rotation detection signal that exists. The encoder device according to claim 1.

4. The encoder processing unit (170) Generates optical rotation information based on the optical rotation detection signal, Generates magnetic rotation information based on the magnetic rotation detection signal, Determines whether the optical rotation information and the magnetic rotation information are each normal, Generates the multi-rotation information based on at least one of the optical rotation information and the magnetic rotation information determined to be normal. The encoder device according to any one of claims 1 to 3.

5. The encoder processing unit (170) issues error information when neither the optical rotation information nor the magnetic rotation information exists, when both the optical rotation information and the magnetic rotation information are not normal, and when one of the optical rotation information and the magnetic rotation information does not exist and the other exists but is not normal. The encoder device according to claim 4.

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