JP2011007658A - Encoder and signal processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encoder that improves the detection accuracy and has high accuracy even when the output of a magnetic detection element varies.SOLUTION: This encoder includes a first position data detection circuit for detecting first position data showing the angle position of an input shaft based on a first detection signal input from a first absolute position encoder, a second position data detection circuit for detecting second position data showing the angle position of an output shaft based on a second detection signal input from a second absolute position encoder, and a position data composing circuit for creating composite position data showing the multiple rotation amount of the input shaft and the angle position within one rotation by composing the first position data and the second position data. The first absolute position encoder or the second absolute position encoder is a magnetic encoder having a rotor rotating in response to the rotation of the input shaft or the output shaft and a plurality of magnetic detection elements arranged around the rotor.

Description

  The present invention relates to an encoder.

As a detection device for detecting the rotation angle, there are optical and magnetic rotation angle detection devices. The optical rotation angle detection device uses a photoelectric conversion element such as a photodiode for the detection unit, and can detect the rotation angle with high precision, but it is an environment where condensation or splash of oil is directly applied to the detection unit. Then it may be difficult to use. A magnetic rotation angle detection device (see, for example, Patent Document 1) uses a magnetic detection element such as a Hall element or a magnetoresistive element, and it is relatively difficult to achieve high detection accuracy. It can also be used in an environment where oil splashes are directly applied to the detection unit. Such a rotation angle detection device may be used for an encoder.
Patent Document 1 is known as a conventional technique.

JP 2004-20548 A

  By the way, in recent years, rotation angle detection devices have been applied to encoders for robots, industrial machine tools, etc., and encoders that have high accuracy and can be used in the harsh environment as described above have been required. Yes.

  Magnetic detection elements such as Hall elements and magnetoresistive elements are used as the detection elements of the magnetic rotation angle detection device described above, but the Hall elements are relatively widely used because of their small size and low price. . However, the Hall element has variations in detection sensitivity and variations in offset voltage variation due to environmental temperature. As described above, since the output of the magnetic detection element such as the Hall element varies, there is a problem that a highly accurate magnetic angle detection device cannot be obtained unless the variations of the magnetic detection elements to be used are uniform.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an encoder having improved accuracy and high accuracy.

  The encoder according to the present invention is a one-rotation type absolute encoder, which is a first absolute position encoder that outputs a first detection signal corresponding to the angular position of the rotated input shaft, and a one-rotation type absolute encoder. A second absolute position encoder that outputs a second detection signal corresponding to the angular position of the output shaft that is rotated at a predetermined transmission ratio according to the rotation of the input shaft, and the first absolute position encoder. A first position data detection circuit for detecting first position data indicating an angular position of the input shaft by a predetermined first signal processing based on the input first detection signal; Based on the second detection signal input from the second absolute position encoder, second position data indicating the angular position of the output shaft is obtained by predetermined second signal processing. A second position data detection circuit to be output; and the first position data and the second position data are combined to generate combined position data indicating an angular position within one rotation together with the multi-rotation amount of the input shaft. A position data synthesizing circuit that generates the first absolute position encoder or the second absolute position encoder around a rotor and a rotor that rotate as the input shaft or the output shaft rotates. A magnetic encoder having a plurality of magnetic detection elements arranged, wherein each magnetic detection element has a connection between an input terminal for supplying power to the magnetic detection element and an output terminal for outputting the detection signal from the magnetic detection element. And a switching circuit for switching to.

  In the signal processing method according to the present invention, the first absolute position is output by the first absolute position encoder, which is a one-rotation type absolute encoder, to output a first detection signal corresponding to the angular position of the rotated input shaft. A second detection signal corresponding to the angular position of the output shaft rotated at a predetermined transmission ratio according to the rotation of the input shaft by the output step and the second absolute position encoder which is a one-rotation type absolute encoder. A first absolute signal output step and a first signal processing set in advance on the basis of the first detection signal input from the first absolute position encoder by the first position data detection circuit. Thus, the second absolute position error is detected by the first position data detecting step for detecting the first position data indicating the angular position of the input shaft and the second position data detecting circuit. A second position data detection step of detecting second position data indicating the angular position of the output shaft by a predetermined second signal processing based on a second detection signal input from the coder; Position data for synthesizing the first position data and the second position data by a position data combining circuit to generate combined position data indicating an angular position within one rotation together with the multi-rotation amount of the input shaft The first absolute position encoder or the second absolute position encoder is disposed around the rotor and the rotor that rotate as the input shaft or the output shaft rotates. A magnetic encoder including a plurality of magnetic detection elements, wherein an output terminal supplies power to the magnetic detection element by a switching circuit and an output for outputting the detection signal from the magnetic detection element A switching step of switching the connection between the child for each of the magnetic detection element, wherein the.

  According to the present invention, an encoder having improved detection accuracy and high accuracy is provided.

It is a block diagram which shows the structure of the encoder by one Embodiment of this invention. 1 is a schematic configuration diagram illustrating an example of a magnetic rotation angle detection device according to a first embodiment of the present invention. It is a block diagram which shows the structure in the 1st connection state of the magnetic-type rotation angle detection apparatus by 1st Embodiment. It is a block diagram which shows the structure in the 2nd connection state of the magnetic-type rotation angle detection apparatus by 1st Embodiment. It is a block diagram which shows the structure of the equalization circuit of a Hall element in the 1st connection state by 1st Embodiment. It is a block diagram which shows the structure of the equalization circuit of a Hall element in the 2nd connection state by 1st Embodiment. In 1st Embodiment, when the input terminal and output terminal of a Hall element are replaced | exchanged periodically, it is an output figure which illustrates the signal output from a synthetic | combination amplifier circuit. In 1st Embodiment, it is an output figure which shows the voltage value before and behind averaging of the signal voltage output from the synthetic | combination amplifier circuit when environmental temperature is changed. In 1st Embodiment, it is a schematic block diagram which shows the structure of the encoder apparatus as an example which interchanges the input terminal and output terminal of a Hall element periodically. 4 is a timing chart illustrating timings at which output signals are converted into digital signals in the first embodiment. It is a block diagram which shows the structure of the signal processing circuit in the encoder apparatus by 1st Embodiment of FIG. It is a wave form diagram which shows waveforms, such as a two-phase signal as an example by this embodiment. It is the figure which showed the rotation angle error of the 1st encoder 3 of the input shaft with respect to the rotation angle of the 2nd encoder 4 of the output shaft by this embodiment. It is a block diagram which shows the structure of the encoder apparatus in the case of the 2nd method of obtaining the error correction value by this embodiment. 17 is a table for generating the table of FIG. 16 for correcting an error according to the present embodiment. It is a table | surface for correct | amending the error by this embodiment. It is a schematic block diagram which shows an example of the magnetic type rotation angle detection apparatus by 2nd Embodiment of this invention. It is a block diagram which shows the structure in the 1st connection state of the magnetic-type rotation angle detection apparatus by 2nd Embodiment. It is a block diagram which shows the structure in the 2nd connection state of the magnetic-type rotation angle detection apparatus by 2nd Embodiment. It is a schematic block diagram which shows an example of the magnetic type rotation angle detection apparatus by 3rd Embodiment of this invention. It is a block diagram which shows the structure in the 1st connection state of the magnetic type rotational angle detection apparatus by 3rd Embodiment. It is a block diagram which shows the structure in the 2nd connection state of the magnetic-type rotation angle detection apparatus by 3rd Embodiment. It is explanatory drawing explaining the synthesis | combining method of a Hall element, and the synthetic | combination Hall element in the magnetic-type rotation angle detection apparatus by this embodiment. In this embodiment, it is a block diagram which shows the structure of the constant current drive circuit which drives a Hall element. It is a block diagram which shows the structure of the differential output circuit in this embodiment. It is a block diagram which shows the structure of the abnormality detection circuit in this embodiment.

[First Embodiment]
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing a configuration of an encoder device (encoder) according to an embodiment of the present invention.

  The encoder device includes a motor 1, a power transmission device 2, a first encoder (first absolute position encoder) 3, a second encoder (second absolute position encoder) 4, an input shaft 10, And an output shaft 11. The controller 8 is a host device, the communication line 9 is a communication line between the controller 8 and the first encoder 3, and the motor control line 14 connects the controller 8 and the motor 1. . The first encoder 3 and the second encoder 4 are connected by a communication line 12 and a setting control line 13.

  The motor 1 rotates the input shaft 10. The power transmission device 2 rotates the output shaft 11 by decelerating at a predetermined transmission ratio (power transmission ratio) according to the rotation of the input shaft 10. That is, in this encoder device, the motor 1 rotates the input shaft 10, and the input shaft 10 rotates, whereby the output shaft 11 rotates through the power transmission device 2. The power transmission device 2 is configured by, for example, one or a plurality of gears, a belt device, a chain device, a drive shaft device, or a combination thereof.

  The first encoder 3 is a one-rotation type absolute encoder, and outputs a first detection signal corresponding to the angular position of the input shaft 10 (first absolute position output step). The first encoder 3 has a function of detecting the angular position of the input shaft 10 of the motor 1 and is a one-rotation type absolute encoder that can detect where the mechanical angle is 360 degrees. The single-rotation absolute encoder is an encoder that cannot detect so-called “multi-rotation data / multi-rotation information”, which is “how many rotations have been rotated” as the rotation information. Similar to the first encoder 3, the second encoder 4 is a one-rotation type absolute encoder, and outputs a second detection signal corresponding to the angular position of the output shaft 11 (second absolute position output step). ).

  The first encoder 3 and the second encoder 4 are, for example, a rotating disk having an N pole and an S pole that rotate according to the rotation of the corresponding shaft of the input shaft 10 or the output shaft 11, and this rotation. It is composed of two Hall elements as magnetic sensor devices arranged at predetermined positions so that the mutual angle is 90 degrees with respect to the rotation center axis of the disk. When the input shaft 10 or the output shaft 11 rotates, the rotating disk corresponding to this shaft rotates as a rotating magnet having N and S poles, so that one cycle per rotation from the Hall element. Sine wave signals are output. Since the Hall elements are arranged at an angle of 90 degrees to each other, a sine wave having a phase difference of 90 degrees, a so-called two-phase pseudo sine wave, is output as a sine wave signal.

  In this way, the first encoder 3 is, for example, two signals each having a sine wave of one cycle for one rotation of the input shaft 10 and having different phases by a predetermined phase. The two-phase sine wave signal is output as the first detection signal. Similarly to the first encoder 3, each of the second encoders 4 is, for example, a sine wave of one cycle for one rotation of the output shaft 11, and each other by a predetermined phase. A two-phase sine wave signal that is two signals having different phases is output as a second detection signal.

  Here, for example, the first encoder 3 outputs N signals in one rotation, the second encoder 4 outputs M signals in one rotation, and the power transmission device 2 is 1: N. The input shaft 10 and the output shaft 11 are connected at a ratio of In this case, since the second encoder 4 rotates by one digit every time the first encoder 3 makes one rotation, the rotation quantity of the input shaft 10 can be detected and the angular position of the input shaft 10 can be detected. Is possible. Therefore, this encoder apparatus can detect N × M rotational positions in the rotation of the input shaft 10, that is, absolute positions, until the output shaft 11 rotates M times.

  That is, this encoder apparatus uses a first encoder 3 that is a one-turn type absolute encoder and a second encoder 4 that is a one-turn type absolute encoder, and the encoder apparatus as a whole is a multi-turn type absolute encoder. Functions as an encoder.

  By the way, the encoder device has a first signal processing circuit 6 and a second signal processing circuit 5 (a second position data detection circuit 50 described later). For example, the first encoder 3 has a first signal processing circuit 6 inside. Further, the second encoder 4 has a second signal processing circuit 5 therein.

  The second detection signal detected by the second encoder 4 is input to the second signal processing circuit 5. The second signal processing circuit 5 is a second signal indicating the angular position of the output shaft 11 through predetermined signal processing based on the second detection signal input from the second encoder 4. Detect position data. That is, the second signal processing circuit 5 detects the second position data by interpolating the input second detection signal (second position data detection step).

  Then, the second signal processing circuit 5 outputs the detected second position data to the first encoder 3 via the communication line 12. When the second signal processing circuit 5 detects the second position data, for example, the second signal processing circuit 5 uses the second resolution with a predetermined resolution of at least twice the transmission ratio of the power transmission device 2. Detect position data. Note that the reason for at least doubling in this way is that it is possible to determine whether the rotation of the output shaft indicated by the second position data is the first half or the second half of the rotation, as will be described later. It is.

  The first encoder 3 has a first signal processing circuit 6 therein. The first position data detected by the second encoder 4 is input to the first signal processing circuit 6 via the communication line 12. Further, the first signal processing circuit 6 interpolates the first detection signal detected by the first encoder 3 to detect first position data indicating the angular position of the input shaft 10 (first Position data detection step).

  Based on the detected first position data and the input second position data, the first signal processing circuit 6 combines the rotation position of the input shaft 10 and the combined position data indicating the angular position within one rotation. Is detected. Then, the first signal processing circuit 6 outputs the detected combined position data to the controller 8 via the communication line 9.

  As a result, the controller 8 can detect the angular position within one rotation together with the number of rotations of the input shaft 10 from the encoder device as a multi-rotation type absolute encoder based on the combined position data. Then, the controller 8 controls the rotation of the motor 1 via the motor control line 14 based on the input composite position data.

  The first signal processing circuit 6 and the second signal processing circuit 5 are connected by a setting control line 13. The first signal processing circuit 6 changes a setting value stored in a later-described storage unit built in the second signal processing circuit 5 via the setting control line 13.

For example, the first absolute position encoder 3 (17-bit resolution) is attached to one of the rotating shafts 10 of the motor 1, and the power transmission device 2 of the first absolute position encoder 3 is attached to the other of the rotating shafts 10. Is done. The power transmission device 2 has a reduction ratio of 30 to 200. Here, the description will be made assuming that the reduction ratio is 100. A second absolute position encoder 4 (11-bit resolution) is mounted on the output shaft 11 of the power transmission device 2, and the first position data detection circuit 5 and the second position data detection circuit 6 obtain the first absolute position encoder 4. From the position data of 1 and the second position data, the position data synthesis circuit (position data synthesis circuit 63 described later) obtains absolute position information for one rotation of the output shaft. The resolution is 2 ¹⁷ (131072) × 100 = 13,107,200. The second position data is generated by detecting the magnetic field intensity from the two-pole magnets of the N pole and the S pole attached to the output shaft 10 by the Hall element.

[Configuration of Magnetic Rotation Angle Detection Device 100 in First Embodiment]
Next, the configuration of the first encoder 3 or the second encoder 4 will be described. Here, the first encoder 3 or the second encoder 4 will be described as the magnetic rotation angle detection device 100.

  FIG. 2 is a schematic block diagram showing the configuration of the magnetic rotation angle detection device 100 according to the first embodiment of the present invention. As shown in FIG. 2 (a), the magnetic rotation angle detection device 100 includes a rotor 106 having a magnet 105, a plurality of magnetic detection elements H1 and H2 arranged around the rotor 106, and the magnetism thereof. It comprises a substrate set 109 on which the detection elements H1 and H2 and other control components are mounted. The magnet 105 is a permanent magnet, for example. The magnetic detection elements H1 and H2 are, for example, Hall elements, respectively. Hereinafter, the magnetic detection elements H1 and H2 will be referred to as Hall elements H1 and H2.

  In FIG. 2A, when the rotor 106 rotates about a rotation axis that is perpendicular to the paper surface, the magnet 105 rotates as the rotor 106 rotates and is detected by the Hall elements H1 and H2. The magnetic field from the magnet 105 changes. The magnetic rotation angle detection device 100 detects the change of the magnetic field by two Hall elements, Hall elements H1 and H2, and detects the rotation angle of the rotor 106 from the detected change amount of the magnetic field.

  Note that the four Hall elements H1 and H2 described with reference to FIG. 2A have, for example, the same detection sensitivity, and each have the same output level. The two Hall elements H1 and H2 are arranged on the plane of the substrate set 109, for example, on the plane having the same direction as the rotation axis of the rotor 106 and the normal vector. It arrange | positions on the periphery so that the angle of Hall element H1 and H2 with respect to the rotating shaft of the rotor 106 may become a predetermined angle. This predetermined angle is, for example, 90 degrees.

  Hall elements H1 and H2 have two output terminals (+ and-), respectively. These two output terminals are connected to input terminals of later-described synthesis amplifier circuits 81 and 82 (see FIG. 2B). Symbol “H1-” in FIG. 2B indicates a signal output from the output terminal − of the Hall element H1 in FIG. Hereinafter, for example, a signal output from the output terminal + of the Hall element H1 is referred to as “signal H1 +”, and a signal output from the output terminal − of the Hall element H1 is referred to as “signal H1-”. The signal output from the Hall element 2 is also referred to as the signal output from the Hall element H1.

  Next, referring to FIG. 2B, the configuration of the magnetic rotation angle detection device 100 that detects the rotation angle of the rotor 106 from the amount of change in the magnetic field detected by the two Hall elements, that is, each Hall element. Synthesis amplifier circuits 81 and 82 (first synthesis circuit and second synthesis circuit) that synthesize and amplify detection signals detected by H1 and H2 will be described.

  The synthesis amplification circuit 81 constitutes a differential addition / subtraction amplification circuit, and includes a resistor RX41 (third synthesis circuit), a resistor RX42 (fourth synthesis circuit), and an addition / subtraction amplification circuit 713 (first differential amplification circuit). ). The signal H1- output from the Hall element H1 is input as a subtraction signal to the first input terminal of the addition / subtraction amplification circuit 713 via the resistor RX41. The signal H1 + output from the Hall element H1 is input as an addition signal to the second input terminal of the addition / subtraction amplification circuit 713 via the resistor RX42.

  As will be described later, the resistor RX41 forms a combining unit 711, and the resistor RX42 forms a combining unit 712. The signals synthesized by the synthesizing unit 711 and the synthesizing unit 712 are added / subtracted and amplified by the addition / subtraction amplification circuit 713 and amplified, and output from the output terminal of the addition / subtraction amplification circuit 713 as an A channel (A phase) approximate sine wave output signal. Is output.

  The input terminal to which the addition signal of the addition / subtraction amplification circuit 713 is input is grounded via the resistor R12. The output terminal of the addition / subtraction amplification circuit 713 is grounded via a series connection of a resistor R13 and a resistor R14. The input terminal to which the subtraction signal of the addition / subtraction amplification circuit 713 is input is connected to a connection point between the resistor R13 and the resistor R14 via the resistor R11.

  Note that in order for the combined amplifier circuit 81 to function as a differential amplifier circuit, it is desirable that the resistor RX41 and the resistor RX42 have the same resistance value, and the resistor R11 and the resistor R12 have the same resistance value.

  The synthetic amplifier circuit 82 has the same configuration as the synthetic amplifier circuit 81, but the Hall elements connected to the synthetic amplifier circuit 81 are different between the Hall elements H1 and H2. Only the differences will be described here. In the composite amplifier circuit 82, the signal H2- is input as a subtraction signal to the addition / subtraction amplifier circuit 723 via the resistor RX41. The signal H2 + is input as an addition signal to the addition / subtraction amplification circuit 723 via the resistor RX42.

  As will be described later, the resistor RX41 constitutes a synthesizer 721, and the resistor RX42 constitutes a synthesizer 722. The signals synthesized by the synthesizing unit 721 and the synthesizing unit 722 are added / subtracted and amplified by the addition / subtraction amplification circuit 723 and amplified, and output from the output terminal of the addition / subtraction amplification circuit 723 as an approximate sine wave output signal of the B channel (B phase). Is output.

  The B channel approximate sine wave output signal is a signal that is electrically 90 degrees out of phase with the A channel approximate sine wave output signal described above. As described with reference to FIG. 2A, the Hall elements H1 and H2 are arranged so that the angle between the Hall elements H1 and H2 is 90 degrees with respect to the rotation axis of the rotor 106. This is because is arranged on the circumference.

  In general, there is an offset in the output of the Hall element. This offset may depend on the temperature change of the environment where the Hall element is placed. For this reason, the output of the Hall element may fluctuate depending on changes in the environmental temperature. Next, the configuration of the magnetic rotation angle detection device 100 that can cancel the offset between the Hall elements H1 and H2 described with reference to FIG. 2 will be described with reference to FIGS.

  First, the configuration of the magnetic rotation angle detection device 100 that can cancel the offset between the Hall elements H1 and H2 in the first embodiment will be described with reference to FIG. The configuration of the magnetic rotation angle detection device 100 shown in FIG. 3 further includes a switching circuit (switching circuit) 20-1 in addition to the configuration of the magnetic rotation angle detection device 100 described above with reference to FIG. 20-2 is added.

  Further, in order to drive the switching circuits 20-1 and 20-2, constant current driving circuits 101 and 102 for supplying a constant current to the switching circuits 20-1 and 20-2 are added. Further, a switching circuit control unit (switching control circuit) 112 for controlling the switching circuits 20-1 and 20-2 is added.

  In FIG. 3, the switching circuits 20-1 and 20-2 have an 8-contact 4-circuit configuration for one Hall element, and the configuration in the case where an analog switch is used is illustrated. This analog switch is, for example, a transistor switch.

  The switching circuits 20-1 and 20-2 each have an S terminal, and the input of the associated Hall element depends on whether the signal input to the S terminal is at the H level or the L level. The connection between the terminal and the output terminal is changed (switching process). The output terminal of the switching circuit control unit 112 is connected to the S terminal of each of the switching circuits 20-1 and 20-2, and the switching circuit control unit 112 outputs an H level or L level control signal from this output terminal. .

  A control signal is input to the T terminal of the switching circuit control unit 112 from the outside. The switching circuit control unit 112 controls which of the H level and L level the voltage output from the S terminal is output based on a control signal input from the outside to the T terminal. Further, in the constant current drive circuit 101, the constant current drive circuit 102, and the switching circuit control unit 112, the power supply voltage + V is input to each power supply terminal.

  Next, the input terminal and output terminal of the Hall element will be described. The Hall elements H1 and H2 described with reference to FIG. 2 each have two input terminals and two output terminals (output terminals + and −). The input terminal of the Hall element is a terminal to which power is supplied to the Hall element. The two input terminals are connected to the corresponding constant current drive circuit (101 or 102), the input terminals of the Hall elements connected in series, or grounded via a resistor. That is, the two input terminals are connected so that power is supplied. On the other hand, the two output terminals are connected to the input terminals of a synthetic amplifier circuit (eg, synthetic amplifier circuit 81).

  The switching circuits 20-1 and 20-2 are connected so that power is supplied to the two input terminals of the corresponding Hall elements, and the two output terminals are connected to the input terminals of the synthesis amplifier circuit. Switching between the first connection state and the second connection state in which power is supplied to the two output terminals and the two input terminals are connected to the input terminals of the synthesis amplifier circuit. Thus, the connection between the output terminal and the output terminal of the Hall element is changed. In this way, each of the switching circuits 20-1 and 20-2 switches the connection between the two input terminals and the two output terminals of the corresponding Hall element.

  FIG. 3 is a diagram when the level input to the S terminals of the switching circuits 20-1 and 20-2 is the H level (in the case of the first connection state described above), for example, and FIG. It is a figure in case the level input into the S terminal of the circuits 20-1 and 20-2 is L level (in the case of the 2nd connection state mentioned above).

  Next, an example of the connection between the input terminal and the output terminal of the Hall element by the switching circuits 20-1 and 20-2 will be described in detail when the signal input to the S terminal is at the H level and at the L level. .

When the signal input to the S terminal is at the H level (in the case of the first connection state described above), the connection of the Hall elements is as shown in FIG. 3, and the constant current drive circuit is provided in the Hall element H1. The output terminal 101 is connected to the first input terminal of the Hall element H1 via the switching circuit 20-1. The second input terminal of the hall element H1 is grounded through the switching circuit 20-1.
Further, the output terminals + and − of the Hall element H1 are connected to the input terminal of the synthesis amplifier circuit 81 through the switching circuit 20-1, as described with reference to FIG. The Hall element H2 connection is the same as the connection of the Hall element H1.

  On the other hand, when the signal input to the S terminal is at the L level (in the second connection state described above), the connection of the Hall element is as shown in FIG. 4, and the constant current is applied to the Hall element H1. The output terminal of the drive circuit 101 is connected to the output terminal − of the Hall element H1 through the switching circuit 20-1. The output terminal + of the hall element H1 is grounded through the switching circuit 20-1. Further, the signal H1 + is output from the first input terminal of the Hall element H1, and the signal H1- is output from the second input terminal of the Hall element H1. These signals are input to the input terminal of the synthesis amplifier circuit 81 through the switching circuit 20-1 as described with reference to FIG. The connection of the Hall element H2 is the same as the connection of the Hall element H1.

  As shown in FIGS. 3 and 4, the connection state between the switching circuits 20-1 and 20-2 is that the voltage level input to the S terminal is H level and L level, that is, the first connection The case of the state and the case of the second connection state are reversed.

  In the following, in the case of the first connection state as shown in FIG. 3, the voltage value of the approximate sine wave output signal of the A channel output from the output terminal of the addition / subtraction amplification circuit 713 is the voltage V1A, as shown in FIG. In the case of the second connection state, the voltage value of the approximate sine wave output signal of the A channel output from the output terminal of the addition / subtraction amplification circuit 713 will be described as the voltage V2A. Similarly, in the case of the first connection state as shown in FIG. 3 described above, the voltage value of the approximate sine wave output signal of the B channel output from the output terminal of the addition / subtraction amplification circuit 723 is set to the voltage V1B, as shown in FIG. In the case of such a second connection state, the voltage value of the B channel approximate sine wave output signal output from the output terminal of the addition / subtraction amplification circuit 723 will be described as the voltage V2B. In the following description, the voltage V1A or the voltage V1B is the voltage V1, and the voltage V2A or the voltage V2B is the voltage V2.

  Next, a method for canceling the offset of the Hall element will be described. An equivalent circuit of the Hall element is shown in the bridge circuit shown in FIG. In this equivalent circuit, the voltage at the input terminal is defined as voltage Vi (+) and voltage Vi (−), and the voltage at the output terminal is defined as voltage Vo (+) and voltage Vo (−). Here, when the magnetic field is zero, the voltage Vu generated at the output terminal in FIG. 5 and the voltage Vu generated at the output terminal when the input / output terminal and the output terminal are switched as shown in FIG. When calculating the sum with ', it is almost zero.

  The voltage Vu and the voltage Vu ′ used in the description of FIGS. 5 and 6 correspond to the voltages V1 and V2 described above. When the change due to the change of the magnetic field is “proportional to magnetic intensity” and the change due to the offset is “X (offset)”, the voltages V1 and V2 are expressed by the following equations 1 and 2. .

  V1 = (Magnetic proportionality) + X (Offset) (Equation 1)

  V2 = (proportional to magnetic intensity) −X (offset) (Formula 2)

  As described above with reference to FIGS. 5 and 6, when the average of the voltage V <b> 1 and the voltage V <b> 2 is taken, “X (offset)” is canceled (see the following Expression 3).

  (V1 + V2) / 2 = (proportional to magnetic intensity) (Equation 3)

  Therefore, for example, the average of the measured values obtained by switching the input terminal and the output terminal of the Hall element, that is, the average of the voltage V1 and the voltage V2, is used as the output from the Hall element. Thereby, the offset of the Hall element can be canceled and the magnetic field can be measured using the Hall element. That is, using the Hall element, the offset of the Hall element can be canceled and the rotation angle of the rotor 106 can be detected.

  The offset cancellation of the Hall element described above has been described for the case where the magnetic field has not changed, that is, the rotor 106 has not rotated. However, even when the rotor 106 rotates, if the rotor 106 can be regarded as substantially not rotating during the period in which the switching circuits 20-1 to 20-4 are switched, there is almost no change in the magnetic field. In addition, the offset of the Hall element can be canceled as in the case where the magnetic field has not changed.

  Next, an example of a signal output from the synthetic amplifier circuit 81 or 82 when the input terminal and the output terminal of the Hall element are periodically exchanged will be described with reference to FIG. In the following, switching between the input terminal and the output terminal of the Hall element will be referred to as switching. Here, description will be made assuming that switching is performed every predetermined period T1.

  In response to switching at intervals of the period T1, the output voltage output from the composite amplifier circuit 81 or 82 alternately repeats the voltage V1 and the voltage V2 in the period T1. Note that when switching is performed at intervals of the period T1, the signal output from the synthesis amplifier circuit 81 or 82 is output with noise caused by switching. However, the noise generated by this switching disappears after a predetermined period (for example, about several tens of ns) has elapsed since switching. Therefore, after switching, data after a predetermined time T2 longer than a period in which noise is generated by switching is measured as an output from the synthesis amplifier circuit 81 or 82. Thereafter, when new data is determined by switching, the value is measured as new data.

  In this way, the voltages V1 and V2 can be measured alternately. Further, by taking the average of the measured voltage and the latest measured voltage, that is, the latest voltages V1 and V2, the offset of the Hall element can be canceled and the rotation angle of the rotor 106 can be detected.

  The period T1 described above may be longer than the time T2 determined in this way. Therefore, the period T1 can be shortened to a period during which noise due to switching occurs. As described above, it is desirable that the measurement of the voltage V1 and the voltage V2 be performed in such a short time that the rotor 106 can be regarded as not rotating. Therefore, it is preferable that the period T1 corresponding to the measurement time interval between the voltage V1 and the voltage V2 can be shortened to a period during which noise due to switching occurs.

  The time T2 can be shortened to a time until noise generated by switching disappears. The time until the noise caused by switching disappears can be determined in advance by simulation or experiment based on the resistance values shown in FIGS. Therefore, the time T2 can be shortened based on the resistance value and the like, and the period T1 can be determined based on the time T2 set in advance so as to be short.

  Next, FIG. 8 shows the voltage value of the signal output from the synthesis amplifier circuit 81 or 82 when the environmental temperature is changed (see reference signs V1 and V2) and the average voltage value (reference sign (V1 + V2). ) / 2). When the environmental temperature changes, the offset fluctuates as the environmental temperature changes, so that the voltage V1 and the voltage V2 fluctuate as shown in FIG. However, the offset of the average (V1 + V2) / 2 of the voltage V1 and the voltage V2 output according to the switching in the period T1 is canceled as described above. Therefore, even if the environmental temperature changes, the average (V1 + V2) / 2 becomes a constant voltage value.

  Next, as described above with reference to FIG. 9, an encoder apparatus as an example in the case where the offset of the Hall element is canceled by periodically exchanging the input terminal and the output terminal of the Hall element. The configuration will be described.

  This encoder device includes a magnetic rotation angle detection device 100 and an arithmetic circuit 200. The magnetic rotation angle detection device 100 has the same configuration as the magnetic rotation angle detection device 100 described above. The magnetic rotation angle detection device 100 outputs approximate sine wave output signals of the A channel and the B channel while switching the Hall element. The arithmetic circuit 200 controls the switching of the Hall element included in the magnetic rotation angle detection device 100 and calculates the average (V1 + V2) / 2 from the signal output from the magnetic rotation angle detection device 100 as described above. Calculated for each channel and B channel. The arithmetic circuit 200 calculates the rotation angle of the rotor 106 based on the average (V1 + V2) / 2 calculated for each of the A channel and the B channel.

  The arithmetic circuit 200 includes an AD converter 201 (conversion circuit) and an arithmetic control unit 202 (rotation angle detection circuit). The arithmetic control unit 202 may be any one of a microcomputer, a DSP (Digital Signal Processor), a dedicated logic circuit, or a combination thereof.

  The arithmetic control unit 202 periodically transmits a clock signal (see reference numeral T1 in FIG. 9) indicating the timing of the above-described period T1 to the magnetic rotation angle detection device 100 in the period T1. Hereinafter, this signal will be described as a T1 signal. The T1 signal is input to the T terminal of the switching circuit control unit 112 included in the magnetic rotation angle detection device 100.

  In addition, the arithmetic control unit 202 periodically outputs to the AD converter 201 a signal having the same frequency as the T1 signal and having a phase shifted by half from the T1 signal in the period T1. This signal corresponds to the signal indicating the time T2 described above, and will be described as a T2 signal hereinafter. Here, the T2 signal is a signal whose phase is half shifted from the T1 signal. However, as described above, this phase shift is a phase corresponding to a time longer than the time until the noise caused by switching disappears. May be.

  Based on the T1 signal input to the T terminal, the switching circuit control unit 112 of the magnetic rotation angle detection device 100 alternately outputs a signal having a voltage of H level and L level from the output terminal in the period T1. . As a result, the switching circuits 20-1 and 20-2 control the switching of the Hall elements, and the analog amplification circuit 81 or 82 of the magnetic rotation angle detection device 100 receives analog signals as shown in FIG. Is output.

  2 to 8, the resistors R12 and R14 of the combined amplifier circuits 81 and 82 are described as being grounded. However, as shown in FIG. 9, the resistors R12 of the combined amplifier circuits 81 and 82 are connected. And R14 may be commonly connected to the reference potential REF. The reference potential REF of the composite amplifier circuits 81 and 82 is input to the AD converter 201 of the arithmetic circuit 200.

  The AD converter 201 corresponds to an analog signal output from the combined amplifier circuit 81 or 82 of the magnetic rotation angle detection device 100 in accordance with the T2 signal input from the arithmetic control unit 202, to the combined amplifier circuits 81 and 82. Each channel is converted into a digital signal and output to the arithmetic control unit 202. Further, the AD converter 201 converts the reference potential REF of the synthesis amplifier circuits 81 and 82 into a digital signal according to the T2 signal input from the arithmetic control unit 202 and outputs the digital signal to the arithmetic control unit 202.

  The arithmetic control unit 202 reads the analog signal for each channel converted into the digital signal output from the AD converter 201 for each period T1, and for each channel, calculates the average of the value read this time and the value read immediately before. Take. In addition, the arithmetic control unit 202 calculates the rotation angle of the rotor 106 by, for example, interpolation processing based on the average for each channel.

  Further, the arithmetic control unit 202 reads the reference potential REF converted into a digital signal output from the AD converter 201 for each period T1. Based on the reference potential REF converted into the digital signal, the arithmetic control unit 202 removes the fluctuation of the reference potential REF from the analog signal for each channel converted into the digital signal output from the AD converter 201. It may be corrected. For example, the arithmetic control unit 202 subtracts the reference potential REF converted into a digital signal from each analog signal converted into a digital signal output from the AD converter 201 and converted into a digital signal. The analog signal for each channel.

  Since the encoder device described with reference to FIG. 9 can read the output from the Hall element without depending on the offset by using the switching circuit 20, the rotation angle of the rotor 106 does not depend on the environmental temperature. It is possible to improve the stability of the accuracy of detecting.

  Next, referring to FIG. 10, the AD converter 201 described with reference to FIG. 9 receives the T2 signal input from the arithmetic control unit 202 from the combination amplification circuits 81 and 82 of the magnetic rotation angle detection device 100. The timing for converting each of the output analog signal (corresponding to the A phase and the B phase) and the reference potential REF into a digital signal will be described.

  Here, a case where the control signal rises at time t1, falls at time t11, and rises at time t21 will be described. In addition, the A phase, the B phase, and the reference potential REF are sequentially converted, and the average is obtained by converting the control signal three times in the period from the rising edge to the falling edge or from the falling edge to the rising edge. explain.

  According to the control signal, the connection state between the switching circuits 20-1 and 20-2 is changed. As shown in FIG. 10, at the timing when the connection state between the switching circuits 20-1 and 20-2 is changed, an analog signal is changed. Noise may occur in the A phase, the B phase, and the reference potential REF.

  Therefore, after the connection state between the switching circuits 20-1 and 20-2 is changed, the AD converter 201 performs the A phase three times at a predetermined first continuous timing when the signal becomes stable. Data is acquired for the B phase three times at a predetermined second consecutive timing and for the reference potential REF three times at a predetermined third consecutive timing. As shown in FIG. 10, after the control signal rises at time t1, the AD converter 201 acquires the A phase three times at times t2, t3, and t4. At the subsequent timings t5, t6, and t7, the B phase is acquired three times. At the subsequent timings t8, t9, and t10, the reference potential REF is acquired three times. The reason for acquiring three times in this way is that the arithmetic control unit 202 averages the values acquired three times.

  For example, assuming that the time interval is every 1 ms and the falling edge of the control signal is a reference, the first A phase is acquired from 1 ms to 3 times, the B phase is acquired from 2 ms to 3 times, and the reference potential REF is acquired from 3 ms to 3 times. Is done. Then, the trailing edge of the control signal is 4 ms, the reference signal REF is acquired from 5 ms to 3 times, the B phase is acquired from 6 ms to 3 times, and the A phase is acquired from 7 ms to 3 times.

  At the rising edge of the control signal, the A phase, the B phase, and the reference signal REF are acquired in this order. At the falling edge of the control signal, the reference signal REFB phase and the A phase are acquired in reverse order. Yes. This is based on the falling edge of the control signal, and the timing for acquiring the first time of each signal in one cycle of the falling edge and the falling edge of the control signal is A phase (1 + 7) / 2 = 4 ms, B phase ( 2 + 6) / 2 = 4 ms and the reference signal REF (3 + 5) / 2 = 4 ms, and all are 4 ms in calculation. The reason for acquiring in this way is that if there is a time difference in the signals used to calculate the position to be acquired, the position to be detected will not be an accurate position. Here, it is assumed that there is no speed change during this 10 ms.

  Note that the time difference between the A phase, the B phase, and the reference signal REF is due to the specifications of the AD converter, and in this embodiment, a case where a 3-input 1-ch AD converter is used is assumed. In calculating the position, if there is a time difference between the timing for acquiring the A phase and the timing for acquiring the B phase, an error may occur when the rotating shaft rotates. In order to maintain the simultaneity in calculation, as shown in FIG. 10 and as described above, the signal of each phase is reversed at the falling edge of the control signal and the rising edge of the control signal with reference to the rising edge of the control signal. In this order, and average the values of each phase (in this case, the average of 6 times of each signal). As a result, the values obtained from the average of the A phase, the B phase, and the reference signal REF correspond to the values acquired at the timing of the fall of the control signal (time t11) as the time positions.

  If the AD converter 201 is a 3-input 3-channel AD converter capable of acquiring 3 channels in parallel, the processing described with reference to FIG. 10 is unnecessary.

  Next, the configuration of the encoder device described with reference to FIG. 1, particularly the configuration of the second signal processing circuit 5 and the first signal processing circuit 6, will be described with reference to FIG. 11. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

<Configuration of Second Signal Processing Circuit 5 and First Signal Processing Circuit 6>
The second signal processing circuit 5 has a second position data detection circuit 50. The second position data detection circuit 50 includes a second interpolation circuit 51, a second position detection circuit 52, a transmission signal generation output unit 53, a transmission ratio information storage unit 56, and a first resolution storage. Part 57 and a second resolution storage part 58. On the other hand, the first signal processing circuit 6 includes a first position data detection circuit 61, a second position data correction circuit 62, a position data synthesis circuit 63, a rotation quantity storage unit 64, and an external communication circuit 65. , A transmission ratio information storage unit 66, a first resolution storage unit 67, and a second resolution storage unit 68.

  As described with reference to FIG. 1, the first encoder 3 and the second encoder 4 generate a two-phase pseudo sine wave of the A phase and the B phase of the magnetic rotation angle detection device 100 of FIG. Output as follows. Then, the first position data detection circuit 61 included in the first signal processing circuit 6 or the second position data detection circuit 50 (second interpolation circuit 51) included in the second signal processing circuit 5 is: It has a configuration corresponding to the arithmetic circuit 200 of FIG.

<Each configuration of the second signal processing circuit 5>
Returning to the description of FIG. 11, first, each configuration of the second position data detection circuit 50 included in the second signal processing circuit 5 will be described. In the transmission ratio information storage unit 56, information indicating a predetermined transmission ratio value of the power transmission device 2 connecting the first encoder 3 and the second encoder 4 is stored in advance as transmission ratio information. ing. In the first resolution storage unit 57, the resolution of the first position data detection circuit 61 is stored in advance as the first resolution. In the second resolution storage unit 58, the resolution of the second position data detection circuit 50 is stored in advance as the second resolution.

  The second interpolation circuit 51 detects the second position data by interpolating the second detection signal input from the second encoder 4. The second position detection circuit 52 uses a value obtained by multiplying the second position data detected by the second interpolation circuit 51 and the transmission ratio information read from the transmission ratio information storage unit 56, as a second resolution storage unit. The value of the integer part of the value divided by the second resolution value read from 58 is calculated as the rotation quantity, and the first value read from the first resolution storage unit 57 to the value of the decimal part of this divided value is calculated. A value obtained by multiplying the resolution value is calculated as an estimated value. The estimated value is position data that is calculated and estimated based on the second detection signal detected by the second encoder 4 from the first position data that is accurately detected by the first encoder 3.

  For example, the second position detection circuit 52 calculates the rotation quantity m and the estimated value s by the following formula.

  m = INT (n (P2 / R2)) (Formula 4)

  s = R1 × (n (P2 / R2) −m) (Formula 5)

  In the above equations 4 and 5, P2 is the second position data detected by the second interpolation circuit 51, and R1 is the first resolution stored in the first resolution storage unit 57. , R2 is the second resolution stored in the second resolution storage unit 58, and n is the transmission ratio information read from the transmission ratio information storage unit 56. Note that INT is an operator that cuts off the decimal part and extracts only the integer part.

  As described above, the second position data detection circuit 50 performs the interpolation process on the second detection signal detected by the second encoder 4 by the second interpolation circuit 51 and the second position detection circuit 52. Based on the obtained value and the transmission ratio information read from the transmission ratio information storage unit 56, the rotation quantity of the first encoder 3 is calculated and the position data corresponding to the first position data is calculated as an estimated value.

  The transmission signal generation output unit 53 generates a transmission signal indicating the rotation quantity value of the input shaft 10 based on the estimated value calculated by the second position detection circuit 52 and outputs the transmission signal to the second position data correction circuit 62. To do. The transmission signal generation output unit 53, for example, converts the transmission signal into a two-phase signal that is a multi-rotation A signal that is a first rectangular wave signal having a phase difference of 90 degrees and a multi-rotation B signal that is a second rectangular wave signal. It produces | generates and outputs as a signal (refer FIG. 12). Note that the two-phase signal is preferably a two-phase rectangular wave signal having a waveform of a rectangular wave in order to have resistance against external noise and the like.

  In FIG. 12, in response to one rotation of the input shaft, that is, in response to the value of the first position data ranging from 0 to 131071, the multi-rotation A signal and the multi-rotation B signal are expressed as H And L, H and H, L and H, and L and L. Here, H and L are, for example, a high level and a low level that are predetermined by the electric signal potential. Each time the input shaft makes one revolution, the multi-rotation A signal and the multi-rotation B signal repeat the above signal pattern.

  The multi-rotation A signal and the multi-rotation B signal generated by the transmission signal generation output unit 53 have the following relationship depending on the transmission ratio n and the resolution R2 of the second position data detection circuit 50 in one rotation of the input shaft. It becomes.

  The multi-rotation A signal is H when the remainder of R2 / 4n is 0 to 2n, and L otherwise. On the other hand, the multi-rotation B signal is H when the remainder of R2 / 4n is n to 3n, and is L otherwise.

  The transmission signal generation output unit 53 generates the multi-rotation A signal and the multi-rotation B signal described above, for example, as follows. The transmission signal generation / output unit 53 calculates a value obtained by dividing the estimated value calculated by the second position detection circuit 52 by the resolution R2 of the second position data detection circuit 50 by 4n from 0. If 2n, the multi-rotation A signal is output as H, and otherwise, the multi-rotation A signal is output as L. Further, the transmission signal generation output unit 53 has a value obtained by dividing the estimated value calculated by the second position detection circuit 52 by the resolution R2 of the second position data detection circuit 50 by 4n, If 1n to 3n, the multi-rotation B signal is output as H; otherwise, the multi-rotation B signal is output as L.

<Each configuration of the first signal processing circuit 6>
Next, each configuration of the first signal processing circuit 6 will be described. Similar to the transmission ratio information storage unit 56, the transmission ratio information storage unit 66 indicates a predetermined transmission ratio value of the power transmission device 2 that connects the first encoder 3 and the second encoder 4. Information is stored in advance as transmission ratio information. Similar to the first resolution storage unit 57, the first resolution storage unit 67 stores in advance the resolution of the first position data detection circuit 61 as the first resolution. Similar to the second resolution storage unit 58, the second resolution storage unit 68 stores in advance the resolution of the second position data detection circuit 50 as the second resolution.

  The first position data detection circuit 61 performs an angle of the input shaft 10 by a predetermined first signal process (interpolation process) based on the first detection signal input from the first encoder 3. First position data indicating a position is detected.

  The second position data correction circuit 62 converts the second position data detected by the second position data detection circuit 50 into the first position detected by the second position data and the first position data detection circuit 61. Correction is performed by a predetermined correction process based on the data.

  The position data synthesis circuit 63 converts the rotation quantity value of the first encoder 3 corrected by the second position data correction circuit 62 and the first position data value detected by the first position data detection circuit 61. Based on this, combined position data is generated (position data combining step). The position data combining circuit 63 combines the first position data detected by the first position data detecting circuit 61 and the second position data detected by the second position data detecting circuit 50. The synthesized position data is synthesized based on the transmission ratio information read from the transmission ratio information storage unit 66.

  Further, the position data synthesis circuit 63 specifically includes the first position data detected by the first position data detection circuit 61 and the second position data detected by the second position data detection circuit 50. When combining, the transmission ratio information read from the transmission ratio information storage unit 66, the first resolution read from the first resolution storage unit 67, and the second resolution read from the second resolution storage unit 68. Based on this, the synthesized position data is synthesized by a predetermined calculation method.

  For example, the position data synthesizing circuit 63 calculates the synthesized position data by the following equation 6.

  Composite position data = P1 + R1 × INT (n × P2 / R2) (Formula 6)

  Here, P1 is first position data, P2 is second position data, and n is a gear ratio. R1 is the resolution of the first position data detection circuit 61, and R2 is the resolution of the second position data detection circuit 50. Note that INT is an operator that cuts off the decimal part and extracts only the integer part.

  The position data synthesizing circuit 63 calculates the integer part (INT) of the value obtained by multiplying the position ratio (P2 / R2) in one rotation of the second position data detection circuit 50 by the gear ratio (n) according to this equation 4. Then, a value obtained by multiplying the calculated integer part value by the resolution value (R1) of the first position data detection circuit 50 and the value of the first position data (P1) is added as the synthesized position data. calculate.

  Further, the position data synthesis circuit 63 outputs the synthesized position data generated by the position data synthesis circuit 63 to the controller 8 through the communication line 9 via the external communication circuit 65.

  Further, the external communication circuit 65 executes communication processing with the controller 8 through the communication line 9. For example, the external communication circuit 65 stores the transmission ratio information received from the controller 8 through the communication line 9 in the transmission ratio information storage unit 66 and also stores it in the transmission ratio information storage unit 56 through the setting control line 13.

  In addition, the external communication circuit 65 stores the first resolution received from the controller 8 through the communication line 9 in the first resolution storage unit 67 and also stores the first resolution in the first resolution storage unit 57 via the setting control line 13. Remember me. The external communication circuit 65 stores the second resolution received from the controller 8 through the communication line 9 in the second resolution storage unit 68 and also stores the second resolution in the second resolution storage unit 58 via the setting control line 13. Remember.

  Each of the transmission ratio information storage unit 66 and the transmission ratio information storage unit 56 is, for example, a nonvolatile memory. Therefore, once the value of the transmission ratio information stored in the transmission ratio information storage unit 66 is set, it will not disappear even if the power of the encoder device is turned off. With this configuration, it is possible to expand the options of the power transmission device 2 that can be used in the encoder device and the transmission ratio of the power transmission device 2.

  In addition, the first resolution storage unit 57, the first resolution storage unit 67, the second resolution storage unit 58, and the second resolution storage unit 68 are also connected to the transmission ratio information storage unit 66 and the transmission ratio information storage unit 56. Similarly, for example, each is a non-volatile memory. Therefore, similarly, the options for the resolution values of the first position data detection circuit 61 and the second position data detection circuit 50 that can be used in the encoder device can be expanded.

  The rotation quantity storage unit 64 stores the value of the rotation quantity of the input shaft 10 detected by the second encoder 4. Then, the second position data correction circuit 62 increases or decreases the value of the rotation quantity stored in the rotation quantity storage unit 64 by 1 in response to reception of the transmission signal from the second signal processing circuit 5. Thus, the value of this rotation quantity is detected.

  The rotation quantity storage unit 64 stores the value of the rotation quantity of the input shaft 10 detected by the second encoder 4 when the encoder device is activated. For example, when the encoder device is activated, the transmission signal generation / output unit 53 of the second signal processing circuit 5 uses the signal pattern of the multi-rotation A signal and the multi-rotation B signal described with reference to FIG. It repeats for the number of rotations, and outputs a multi-rotation signal for the number of rotations as an initial value setting signal. Then, the second position data correction circuit 62 causes the rotation quantity storage unit 64 to store a value corresponding to the initial value setting signal received from the transmission signal generation output unit 53 of the second signal processing circuit 5. As a result, the rotation quantity storage unit 64 stores information on the rotation quantity.

  Thereafter, the second position data correction circuit 62 increases or decreases the value of the rotation quantity stored in the rotation quantity storage unit 64 in response to reception of the transmission signal from the second signal processing circuit 5. . The error correction circuit 621 corrects the angle error of the power transmission device. In this manner, the value of the rotation quantity of the input shaft 10 is detected from the rotation of the output shaft 11.

<Details of Second Position Data Correction Circuit 62>
Next, the configuration of the second position data correction circuit 62 will be described more specifically. For example, there may be a deviation between the first position data indicating the rotational position of the input shaft 10 and the second position data indicating the rotational position of the output shaft 11. This is, for example, a shift caused by the meshing between the input shaft 10 and the power transmission device 2 and between the power transmission device 2 and the output shaft 11, and is physically caused.

  Therefore, as shown in FIG. 13, the timing varies between the rotation quantity (m) calculated from the second position data and the first position data (P1) indicating the rotation position of the input shaft 10. In this case, there is a possibility of deviation. If such a deviation occurs, the position data combining circuit 63 cannot normally generate the combined position data. Therefore, as shown in FIG. 14, the second position data correction circuit 62 is configured so that the position data synthesis circuit 63 can normally generate the synthesized position data even when there is such a deviation. A correction value Δm is calculated, and the calculated correction value Δm is added to the rotation quantity (m) to be corrected.

  Here, a method of correcting the rotation quantity by the second position data correction circuit 62 will be described with reference to FIGS. 13 and 14. Here, a case where the value of the first position data is 17 bits will be described.

As shown in FIG. 13, the output shaft 11 rotates as the input shaft 10 rotates, and the rotation quantity m is calculated based on the value P2 of the second position data. Further, the value P1 of the first position data repeats a value from 0 to 131071 (= 2 ¹⁷ −1). That is, as the value P1 of the first position data repeats a value from 0 to 131071 (= 2 ¹⁷ −1), for example, the rotation quantity m changes in order of 10, 11, and 12, for example. Between the change position of the input shaft rotation quantity detected by the value P1 of the first position data (for example, the timing at which the value P1 of the first position data becomes 0) and the timing at which the rotation quantity m changes. There is a gap.

As shown in FIG. 14, in the second position data correction circuit 62, for example, the value P1 of the first position data is in the range of 0 to 32767 (= 2 ¹⁷ × 1 / 4-1). If the calculated rotation quantity m is the latter half, the correction value Δm (= 1) is added to the rotation quantity m value to correct the rotation quantity m value. Here, that the calculated rotation quantity m is the latter half means that the calculated rotation quantity m is m, but close to m + 1.

Further, as shown in FIG. 14, the second position data correction circuit 62 is configured such that, for example, the value P1 of the first position data is changed from 98304 (= 2 ¹⁷ × 3 / 4-1) to 131071 (= 2). in the range of ^{17 -1),} and when the rotation number m that is calculated is the first half, the value in the correction value Δm of the rotation quantity m (= - 1) by adding a value of the rotation quantity m to correct. Here, the calculated rotation quantity m being in the first half means that the calculated value of the rotation quantity m is m but close to m−1.

  By the way, the determination as to whether the calculated rotation quantity m is the second half or the first half is made based on the estimated value. For example, the second position data correction circuit 62 determines that the estimated value calculated by the second position detection circuit 52 is the first half when the estimated value is smaller than 0.5 (half circle), and the estimated value If the value is 0.5 (half circle) or more, it is determined to be the second half.

  In FIG. 14, the rotational position of the input shaft 10 detected by the value of the rotational quantity detected by the first encoder 3 is the first quarter of the rotation in one rotation of the input shaft 10 (from 0 to 32767). ) Or the latter quarter of the region (98304 to 131071). However, in order to detect the deviation, the rotational position of the input shaft 10 detected by the value of the rotation quantity detected by the first encoder 3 is the first half of the rotation or the second half of the rotation in one rotation of the input shaft 10. It may be determined whether it is the area.

  Therefore, the second position data correction circuit 62 is configured such that the rotational position of the input shaft 10 estimated by the estimated value calculated by the second position detection circuit 52 is in the first half region of rotation in one rotation of the input shaft 10. The rotation position of the input shaft 10 detected based on the rotation quantity value detected by the first encoder 3 is the first half region or the second half region of rotation in one rotation of the input shaft 10. You may make it determine. The second position data correction circuit 62 may correct the value of the rotation quantity calculated by the second position detection circuit 52 when the two determination results are different.

  Specifically, the second position data correction circuit 62 is configured such that the rotational position of the input shaft 10 estimated by the value of the estimated value calculated by the second position detection circuit 52 is rotated in one rotation of the input shaft 10. The rotation position of the input shaft 10 detected by the value of the first position data detected by the first position data detection circuit 61 is the first half region of rotation in one rotation of the input shaft 10. In this case, 1 is added to the value of the rotation quantity calculated by the second position detection circuit 52 for correction.

  On the other hand, the second position data correction circuit 62 reverses the rotational position of the input shaft 10 estimated by the estimated value calculated by the second position detection circuit 52 in the first half of the rotation of the input shaft 10. And the rotation position of the input shaft 10 detected by the value of the first position data detected by the first position data detection circuit 61 is the second half of the rotation in one rotation of the input shaft 10. Is corrected by adding -1 to the value of the rotation quantity calculated by the second position detection circuit 52, that is, subtracting one.

  By the way, the second position data correction circuit 62 determines the rotational position of the input shaft 10 of the rotation quantity of the input shaft 10 based on the transmission signal input from the transmission signal generation output unit 53 of the second position data detection circuit 50. It is determined whether the rotation is in the first half region or the second half region in one rotation, and the value of the rotation quantity is corrected.

  Here, the case where the signal input to the second position data correction circuit 62 is a two-phase rectangular wave of a multi-rotation A signal and a multi-rotation B signal as shown in FIG. 12 will be described.

  For example, as shown in FIG. 12, the multi-rotation A signal and the multi-rotation B signal are signals of H and L, H and H, L and H, and L and L every time the input shaft makes one revolution. It changes with the pattern. As a result, the second position data correction circuit 62 determines that the first half region of rotation is one rotation of the input shaft when the multi-rotation A signal and the multi-rotation B signal are H and L or H and H. To do. On the contrary, the second position data correction circuit 62 determines that it is the latter half of the rotation in one rotation of the input shaft when L and H or L and L.

  More specifically, the second position data correction circuit 62 is a region where rotation starts at a quarter of one rotation of the input shaft when the multi-rotation A signal and the multi-rotation B signal are H and L, respectively. Is determined. In addition, when the multi-rotation A signal and the multi-rotation B signal are L and L, the second position data correction circuit 62 determines that the rotation is a quarter of the end of rotation in one rotation of the input shaft. .

  The second position data correction circuit 62 sequentially inputs the multi-rotation A signal and the multi-rotation B signal in the signal pattern of H and L, H and H, L and H, and L and L. By detecting the change, it is detected that the input shaft has made one rotation. On the contrary, the second position data correction circuit 62 receives the signals that the input multi-rotation A signal and multi-rotation B signal are L and L, L and H, H and H, and H and L. By detecting changes in order in the pattern, it is detected that the input shaft has made one rotation in the reverse direction, that is, -1 rotation.

  In the above description, the case where the signal input to the second position data correction circuit 62 is a two-phase rectangular wave of a multi-rotation A signal and a multi-rotation B signal as shown in FIG. The signal processing in the second position data correction circuit 62 is the same when the two-phase rectangular wave is a two-phase sine wave signal.

  For example, in the case of a two-phase sine wave signal, the second phase data correction circuit 62 converts the two-phase sine wave signal into a two-phase rectangular wave, and based on the converted two-phase rectangular wave, The position data correction circuit 62 may execute the signal processing described above with reference to FIGS. 13 and 14.

  Further, the two-phase sine wave signal may be the same as the signal when the estimated value s is output from the second signal processing circuit 5 to the first signal processing circuit 6. Even in this case, the position data combining circuit 63 can generate combined position data using the values corrected by the failure detection circuit 622 and the second position data correction circuit 62.

  In the case of a two-phase sine wave signal, since the estimated value s can be output from the second signal processing circuit 5 to the first signal processing circuit 6, the first position data becomes an abnormal value. Even so, the position data synthesizing circuit 63 can generate the synthesized position data using the estimated value s instead of the first position data according to the above-described Expression 5.

  As described above, the second position data is transmitted as serial data to the position data synthesis circuit. On the other hand, the first position data obtained from the first detection signal representing the rotational position of the output shaft of the motor is also input to the position data synthesis circuit. The position data synthesis circuit performs a process of matching the position of the motor input shaft with the changing point of the rotation quantity.

  This process will be described with reference to the table shown in FIG. In FIG. 15, the first position data (rotation angle of the motor) is described in a column, and the second position data (rotation angle of the output shaft) is represented in a row. Since the reduction ratio of the reduction gear is 100, the numerical value in the second column from the left increases by 1 every 3.6 degrees. The unit is degrees. The multi-rotation value obtained from the second position data is the third column from the left. Numerical values 0, -1, +1, and ERROR obtained from the relationship between this value and the first position data are summarized in the table of FIG.

  For example, this table may be stored in advance in the correction value storage unit. For example, the correction value storage unit stores in advance a correction value for correcting the counted rotation quantity in association with the counted rotation quantity and the first position data detected by the first position data detection circuit. You may do it. Then, the second position data correction circuit reads the correction value associated with the counted rotation quantity and the first position data detected by the first position data detection circuit from the correction value storage unit, and reads the read value. The correction value may be added to the counted number of rotations to correct the counted number of rotations.

[Second Embodiment]
Next, the configuration of the magnetic rotation angle detection device 100 according to the second embodiment of the present invention will be described with reference to FIG. The same components as those of the magnetic rotation angle detector 100 according to the first embodiment described above with reference to FIGS. 2 to 4 are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 17A, the magnetic rotation angle detection device 100 according to the second embodiment is further compared to the magnetic rotation angle detection device 100 according to the second embodiment shown in FIG. Hall elements H3 and H4 are provided. That is, the magnetic rotation angle detection device 100 according to the second embodiment has a total of four Hall elements, that is, the Hall elements H1, H2, H3, and H4.

  In FIG. 17A, when the rotor 106 rotates about the rotation axis perpendicular to the paper surface, the magnet 105 rotates with the rotation of the rotor 106, and the Hall elements H1, H2, H3, H4 The magnetic field from the detected magnet 105 changes. The magnetic rotation angle detection device 100 detects the change of the magnetic field by four Hall elements H1, H2, H3, and H4, and determines the rotation angle of the rotor 106 from the detected change amount of the magnetic field. To detect.

  The four Hall elements H1, H2, H3, and H4 described with reference to FIG. 17A have, for example, the same detection sensitivity, and each have the same output level. Yes. The four Hall elements H1, H2, H3, and H4 are arranged on the plane of the substrate set 109, for example, on the plane that has the same direction as the rotation axis of the rotor 106 and the normal vector. And arranged on a circumference equidistant from the rotation axis of the rotor 106. The Hall elements H1, H2, H3, and H4 are arranged at equal intervals (in this case, an equal angle of 90 degrees with the rotation axis of the rotor 106 as the center). The hall elements H1 and H3 and the hall elements H2 and H4 that are paired with each other are arranged so as to face each other with the rotation axis of the rotor 106 as a center, and are 180 degrees around the rotation axis of the rotor 106. They are arranged at an angle.

  Next, referring to FIG. 17B, the configuration of the magnetic rotation angle detection device 100 that detects the rotation angle of the rotor 106 from the amount of change in the magnetic field detected by the four Hall elements, that is, each Hall element. Synthesis amplifier circuits 81 and 82 (first synthesis circuit and second synthesis circuit) that synthesize and amplify detection signals detected by H1, H2, H3, and H4 will be described.

  The synthesis amplification circuit 81 constitutes a differential addition / subtraction amplification circuit, and a synthesis unit 711 (third synthesis circuit) and a synthesis unit 712 (fourth synthesis) that synthesize signals output from the four Hall elements. Circuit) and an addition / subtraction amplifier circuit 713 (first differential amplifier circuit). The combining unit 711 includes two resistors RX41. The combining unit 712 includes two resistors RX42. The output terminals of the corresponding Hall elements H1 and H3 are connected to the first terminals of the two resistors RX41, respectively, and the second terminals of the two resistors RX41 are combined to add / subtract amplification circuit 713. Are connected to the first input terminal. The connection of the two resistors RX42 is the same as the connection of the two resistors RX41.

  The synthesizer 711 synthesizes two signals, the signal H1− and the signal H3 +. For example, two signals of the signal H1− and the signal H3 + are input to the first terminal of the resistor RX41 included in the combining unit 711 corresponding to each signal. And the signal output from the 2nd terminal of each resistance RX41 is synthesize | combined in the connection point of the 2nd terminal of each resistance RX41. The synthesized signal is input to the addition / subtraction amplification circuit 713 as a subtraction signal.

  On the other hand, the synthesizer 712 synthesizes the two signals of the signal H1 + and the signal H3-. For example, two signals of the signal H1 + and the signal H3- are input to the first terminal of the resistor RX42 included in the combining unit 712 corresponding to each signal. And the signal output from the 2nd terminal of each resistance RX42 is synthesize | combined in the connection point of the 2nd terminal of each resistance RX41. The synthesized signal is input to the addition / subtraction amplification circuit 713 as an addition signal.

  The signals synthesized by the synthesis unit 711 and the synthesis unit 712 are added / subtracted by the addition / subtraction amplification circuit 713 in the same manner as the synthesis amplification circuit 81 of the magnetic rotation angle detection device 100 according to the first embodiment shown in FIG. And amplified and output from the output terminal of the addition / subtraction amplification circuit 713 as an A channel (A phase) approximate sine wave output signal.

  The synthetic amplifier circuit 82 has the same configuration as the synthetic amplifier circuit 81, but is different from the synthetic amplifier circuit 81 in the connection method with the Hall element. Only the differences will be described here.

  In the combined amplifier circuit 82, the two signals H2- and H4 + are input to the first terminal of the resistor RX41 included in the combining unit 721 corresponding to each signal. Then, by combining the signals output from the second terminals of the resistors RX41, the combining unit 721 combines the two signals H2- and H4 +. The synthesized signal is input to the addition / subtraction amplification circuit 723 as a subtraction signal.

  On the other hand, two signals of the signal H2 + and the signal H4- are input to the first terminal of the resistor RX42 included in the combining unit 722 corresponding to each signal. Then, by combining the signals output from the second terminals of the resistors RX42, the combining unit 722 combines the two signals H2 + and H4-. Then, the synthesized signal is input to the addition / subtraction amplification circuit 723 as an addition signal.

  The signals synthesized by the synthesis unit 721 and the synthesis unit 722 are added / subtracted and amplified by the addition / subtraction amplification circuit 723 and amplified, and output from the output terminal of the addition / subtraction amplification circuit 723 as an approximate sine wave output signal of the B channel (B phase). Is done. The B channel approximate sine wave output signal is a signal that is electrically 90 degrees out of phase with the A channel approximate sine wave output signal described above.

  According to the second embodiment described above, the output signal can be increased by detecting the north and south poles of the magnet 105 by the opposing hall elements. Moreover, detection accuracy can be improved by detecting the N pole and the S pole.

  Next, a magnetic rotation angle detection device 100 capable of canceling the offset of the Hall element will be described with reference to FIGS. 18 and 19 in the case of the second embodiment.

  First, the configuration of the magnetic rotation angle detection device 100 used in the second embodiment will be described with reference to FIG. The configuration of the magnetic rotation angle detection device 100 according to the second embodiment shown in FIG. 18 is further different from the configuration of the magnetic rotation angle detection device 100 according to the first embodiment described above with reference to FIG. Switching circuits (switching circuits) 20-3 to 20-4 are added.

  In FIG. 18, the switching circuits 20-1 to 20-4 have a configuration of eight contacts and four circuits for one Hall element, and a configuration in the case where an analog switch is used is illustrated. This analog switch is, for example, a transistor switch.

  Each of the switching circuits 20-1 to 20-4 has an S terminal, and the input of the associated Hall element depends on whether the signal input to the S terminal is at the H level or the L level. Change the connection between the terminal and the output terminal. The output terminal of the switching circuit control unit 112 is connected to the S terminal of each of the switching circuits 20-1 to 20-4, and the switching circuit control unit 112 outputs an H level or L level control signal from this output terminal. .

  A control signal is input to the T terminal of the switching circuit control unit 112 from the outside. The switching circuit control unit 112 controls which of the H level and L level the voltage output from the S terminal is output based on a control signal input from the outside to the T terminal. Further, in the constant current drive circuit 101, the constant current drive circuit 102, and the switching circuit control unit 112, the power supply voltage + V is input to each power supply terminal.

  The switching circuits 20-1 to 20-4 are connected so that power is supplied to the two input terminals for the corresponding Hall elements, and the two output terminals are connected to the input terminals of the synthesis amplifier circuit. Switching between the first connection state and the second connection state in which power is supplied to the two output terminals and the two input terminals are connected to the input terminals of the synthesis amplifier circuit. Thus, the connection between the output terminal and the output terminal of the Hall element is changed. In this way, each of the switching circuits 20-1 to 20-4 switches the connection between the two input terminals and the two output terminals of the corresponding Hall element.

  18 is a diagram when the level input to the S terminals of the switching circuits 20-1 to 20-4 is H level (in the case of the first connection state described above), for example, and FIG. It is a figure in case the level input into the S terminal of the circuits 20-1 to 20-4 is L level (in the case of the 2nd connection state mentioned above).

  Next, an example of connection between the input terminal and the output terminal of the Hall element by the switching circuits 20-1 to 20-4 will be described in detail when the signal input to the S terminal is at the H level and at the L level. .

  When the signal input to the S terminal is at the H level (in the first connection state described above), the connection of the Hall elements is as shown in FIG. 18, and in the combination of the Hall elements H1 and H3, The output terminal of the constant current drive circuit 101 is connected to the first input terminal of the Hall element H1 through the switching circuit 20-1. The second input terminal of the Hall element H1 is connected to the first input terminal of the Hall element H3 via the switching circuit 20-1 and the switching circuit 20-3. The second input terminal of the hall element H3 is grounded via the switching circuit 20-3. Further, the output terminals + and − of the Hall element H1 and the output terminals + and − of the Hall element H3 are connected to the input terminals of the synthesis amplifier circuit 81 as described in the second embodiment of FIG. . The connection of the set of Hall elements H2 and H4 is the same as the connection of the set of Hall elements H1 and H3.

  On the other hand, when the signal input to the S terminal is at the L level (in the case of the second connection state described above), the connection of the Hall elements is as shown in FIG. 19, and the combination of the Hall elements H1 and H3. , The output terminal of the constant current drive circuit 101 is connected to the output terminal − of the Hall element H1 through the switching circuit 20-1. The output terminal + of the Hall element H1 is connected to the output terminal − of the Hall element H3 through the switching circuit 20-1 and the switching circuit 20-3. The output terminal + of the hall element H3 is grounded through the switching circuit 20-3. Further, the signal H1 + is output from the first input terminal of the Hall element H1, and the signal H1- is output from the second input terminal of the Hall element H1. A signal H3 + is output from the first input terminal of the Hall element H3, and a signal H3- is output from the second input terminal of the Hall element H3. These signals are input to the input terminal of the synthesis amplifier circuit 81 as described in the second embodiment of FIG. The connection of the set of Hall elements H2 and H4 is the same as the connection of the set of Hall elements H1 and H3.

  As shown in FIGS. 18 and 19, the connection state of the switching circuits 20-1 to 20-4 is reversed when the voltage level input to the S terminal is H level and L level.

[Third Embodiment]
Next, the configuration of the magnetic rotation angle detection device 100 according to the third embodiment of the present invention will be described with reference to FIG. The configuration of the magnetic rotation angle detection device 100 according to the first embodiment described above with reference to FIGS. 2 to 4 or the configuration of the magnetic rotation angle detection device 100 according to the second embodiment described above with reference to FIGS. The same reference numerals are given to the same configurations as the configurations, and the description thereof is omitted.

  The magnetic rotation angle detection device 100 according to the third embodiment shown in FIG. 20 (a) has four holes as compared with the magnetic rotation angle detection device 100 according to the second embodiment shown in FIG. 17 (a). The connection methods of the elements H1, H2, H3, and H4 and the synthetic amplifier circuits 81 and 82 are different. Hereinafter, differences will be described.

  First, referring to FIG. 20B, the configuration of the magnetic rotation angle detection device 100 that detects the rotation angle of the rotor 106 from the amount of change in the magnetic field detected by the four Hall elements described above, that is, each Hall element. Synthesis amplifier circuits 81 and 82 (first synthesis circuit and second synthesis circuit) that synthesize and amplify detection signals detected by H1, H2, H3, and H4 will be described.

  The synthesis amplification circuit 81 constitutes a differential addition / subtraction amplification circuit, and a synthesis unit 711 (third synthesis circuit) and a synthesis unit 712 (fourth synthesis) that synthesize signals output from the four Hall elements. Circuit) and an addition / subtraction amplifier circuit 713 (first differential amplifier circuit). The synthesizing unit 711 includes four resistors RX41. The combining unit 712 includes four resistors RX42. The output terminals of the corresponding Hall elements H1, H2, H3, and H4 are connected to the first terminals of the four resistors RX41, respectively, and the second terminals of the four resistors RX41 are combined to perform addition / subtraction. The amplifier circuit 713 is connected to the first input terminal. The connection of the four resistors RX42 is the same as the connection of the four resistors RX41.

  The synthesizer 711 synthesizes four signals of the signal H1-, the signal H2-, the signal H3 +, and the signal H4 +. For example, four signals of the signal H1-, the signal H2-, the signal H3 +, and the signal H4 + are input to the first terminal of the resistor RX41 included in the combining unit 711 corresponding to each signal. And the signal output from the 2nd terminal of each resistance RX41 is synthesize | combined in the connection point of the 2nd terminal of each resistance RX41. The synthesized signal is input to the addition / subtraction amplification circuit 713 as a subtraction signal.

  On the other hand, the synthesizing unit 712 synthesizes four signals of the signal H1 +, the signal H2 +, the signal H3-, and the signal H4-. For example, four signals of signal H1 +, signal H2 +, signal H3-, and signal H4- are input to the first terminal of the resistor RX42 included in the combining unit 712 corresponding to each signal. And the signal output from the 2nd terminal of each resistance RX42 is synthesize | combined in the connection point of the 2nd terminal of each resistance RX41. The synthesized signal is input to the addition / subtraction amplification circuit 713 as an addition signal.

  The signals synthesized by the synthesizing unit 711 and the synthesizing unit 712 are added / subtracted and amplified by the addition / subtraction amplification circuit 713 and amplified, and output from the output terminal of the addition / subtraction amplification circuit 713 as an A channel (A phase) approximate sine wave output signal. Is output.

  The input terminal to which the addition signal of the addition / subtraction amplification circuit 713 is input is grounded via the resistor R12. The output terminal of the addition / subtraction amplification circuit 713 is grounded via a series connection of a resistor R13 and a resistor R14. The input terminal to which the subtraction signal of the addition / subtraction amplification circuit 713 is input is connected to a connection point between the resistor R13 and the resistor R14 via the resistor R11.

  Note that, since the combined amplifier circuits 81 and 82 each function as a differential amplifier circuit, the four resistors RX41 and the four resistors RX42 have the same resistance value, and the resistor R11 and the resistor R12 have the same resistance value. It is desirable to be a value.

  The synthetic amplifier circuit 82 has the same configuration as that of the synthetic amplifier circuit 81, but is different from the synthetic amplifier circuit 81 in the method of connecting the four Hall elements H1, H2, H3, and H4. Only the differences will be described here.

  In the combined amplifier circuit 82, the four signals of the signal H2-, the signal H3-, the signal H4 +, and the signal H1 + are input to the first terminal of the resistor RX41 included in the combining unit 721 corresponding to each signal. Then, by synthesizing the signals output from the second terminals of the resistors RX41, the synthesizing unit 721 synthesizes four signals of the signal H2-, the signal H3-, the signal H4 +, and the signal H1 +. The synthesized signal is input to the addition / subtraction amplification circuit 723 as a subtraction signal.

  On the other hand, four signals of signal H2 +, signal H3 +, signal H4-, and signal H1- are input to the first terminal of the resistor RX42 included in the combining unit 722 corresponding to each signal. Then, by synthesizing signals output from the second terminals of the resistors RX42, the synthesizing unit 722 synthesizes the four signals H2 +, H3 +, H4-, and H1-. Then, the synthesized signal is input to the addition / subtraction amplification circuit 723 as an addition signal.

  The signals synthesized by the synthesis unit 721 and the synthesis unit 722 are added / subtracted and amplified by the addition / subtraction amplification circuit 723 and amplified, and output from the output terminal of the addition / subtraction amplification circuit 723 as an approximate sine wave output signal of the B channel (B phase). Is done. The B channel approximate sine wave output signal is a signal that is electrically 90 degrees out of phase with the A channel approximate sine wave output signal described above. This phase relationship will be described later with reference to FIG.

  FIG. 6 is a diagram when the level input to the S terminals of the switching circuits 20-1 to 20-4 is H level (in the case of the first connection state described above), for example, and FIG. It is a figure in case the level input into the S terminal of the circuits 20-1 to 20-4 is L level (in the case of the 2nd connection state mentioned above).

  Next, an example of connection between the input terminal and the output terminal of the Hall element by the switching circuits 20-1 to 20-4 will be described in detail when the signal input to the S terminal is at the H level and at the L level. .

  When the signal input to the S terminal is at the H level (in the first connection state described above), the connection of the Hall elements is as shown in FIG. 21, and in the combination of the Hall elements H1 and H3, The output terminal of the constant current drive circuit 101 is connected to the first input terminal of the Hall element H1 through the switching circuit 20-1. The second input terminal of the Hall element H1 is connected to the first input terminal of the Hall element H3 via the switching circuit 20-1 and the switching circuit 20-3. The second input terminal of the hall element H3 is grounded via the switching circuit 20-3. Further, the output terminals + and − of the Hall element H1 and the output terminals + and − of the Hall element H3 are connected to the input terminals of the synthesis amplifier circuit 81 as described in the first embodiment. The connection of the set of Hall elements H2 and H4 is the same as the connection of the set of Hall elements H1 and H3.

  On the other hand, when the signal input to the S terminal is at L level (in the case of the second connection state described above), the connection of the Hall elements is as shown in FIG. 22, and the combination of the Hall elements H1 and H3. , The output terminal of the constant current drive circuit 101 is connected to the output terminal − of the Hall element H1 through the switching circuit 20-1. The output terminal + of the Hall element H1 is connected to the output terminal − of the Hall element H3 through the switching circuit 20-1 and the switching circuit 20-3. The output terminal + of the hall element H3 is grounded through the switching circuit 20-3. Further, the signal H1 + is output from the first input terminal of the Hall element H1, and the signal H1- is output from the second input terminal of the Hall element H1. A signal H3 + is output from the first input terminal of the Hall element H3, and a signal H3- is output from the second input terminal of the Hall element H3. These signals are input to the input terminal of the synthesis amplifier circuit 81 as described in the first embodiment. The connection of the set of Hall elements H2 and H4 is the same as the connection of the set of Hall elements H1 and H3.

  As shown in FIGS. 21 and 22, the connection state of the switching circuits 20-1 to 20-4 is reversed when the voltage level input to the S terminal is H level and L level.

  Next, the relationship between the plurality of Hall elements H1, H2, H3, and H4 described in FIG. 20 and the combined amplifier circuits 81 and 82 will be described with reference to FIG.

  Among the plurality of Hall elements H1, H2, H3, and H4, Hall elements included in the first region divided by the first plane including the rotation center axis of the rotor 106 are defined as a first Hall element group. A Hall element included in the second region divided by one plane is defined as a second Hall element group. In addition, among the plurality of Hall elements H1, H2, H3, and H4, the second plane is divided by a second plane that includes the rotation center axis and that forms a predetermined angle with the first plane. Hall elements included in the third region are defined as a third Hall element group, and Hall elements included in the fourth region divided by the second plane are defined as a fourth Hall element group. This predetermined angle is, for example, 90 degrees.

  As shown in FIG. 23, an axis that is the rotation center axis of the rotor 106 and is perpendicular to the paper surface is defined as a Z axis. Two axes that are perpendicular to the Z-axis and that are horizontal and perpendicular to the paper surface are defined as an X-axis and a Y-axis. Here, for the sake of explanation, as the rotation center axis of the rotor 106, the angular position of the Hall element H1 is 0 degree, the angular position of the Hall element 2 is 90 degrees, the angular position of the Hall element 3 is 180 degrees, The angular position of the element 4 is 270 degrees.

  For example, as indicated by reference numeral 301, the first plane is assumed to be a plane that is at an angular position of 135 degrees and 315 degrees with respect to the rotation center axis of the rotor 106 and is perpendicular to the paper surface. In this case, the first Hall element group is Hall elements H1 and H2, and the second Hall element group is Hall elements H3 and H4. Further, as indicated by reference numeral 302, the second plane is assumed to be a plane perpendicular to the paper surface at angular positions of 45 degrees and 225 degrees with respect to the rotation center axis of the rotor 106. In this case, the third Hall element group is Hall elements H2 and H3, and the fourth Hall element group is Hall elements H4 and H1.

  The synthesis amplifier circuit 81 synthesizes detection signals detected by the first hall element group and the second hall element group, respectively. As shown in FIG. 20B, in the synthesis amplifier circuit 81, the signal H1-, the signal H2-, the signal H3 +, and the signal H4 + are input to the synthesis unit 711, and the signal H1 +, Signal H2 +, signal H3-, and signal H4- are input.

  The input of this signal will be described by dividing it into a first Hall element group and a second Hall element group. For the first Hall element group, the signal H1- The signal H2- is input, and the signal H1 + and the signal H2 + are input to the combining unit 712. Then, the addition / subtraction amplification circuit 713 outputs a signal corresponding to the difference between the signal H1- and the signal H2- synthesized by the synthesis unit 711 and the signal H1 + and the signal H2 + synthesized by the synthesis unit 712. Therefore, the combined amplifier circuit 81 for the first Hall element group is configured to be a Hall element (first combined magnetic detection element) in which Hall elements H1 and H2 included in the first Hall element group are combined. The approximate sine wave output signal of the A channel is output.

  The Hall element obtained by combining the Hall elements H1 and H2 described above is a position between the Hall elements H1 and H2, for example, a position indicated by reference numeral A1 in FIG. This corresponds to a synthetic Hall element located at 45 degrees as the center.

  Similarly, the combined amplification circuit 81 outputs an approximate sine wave of the A channel so as to become a Hall element (second combined magnetic detection element) obtained by combining Hall elements H3 and H4 included in the second Hall element group. A signal is output. The Hall element obtained by combining the Hall elements H3 and H4 described above is a position that is intermediate between the Hall elements H3 and H4, for example, a position indicated by reference numeral A2 in FIG. This corresponds to a synthetic Hall element located at a position of 225 degrees as the center.

  The synthetic amplifier circuit 81 synthesizes the synthetic amplifier circuit 81 for the first Hall element group and the synthetic amplifier circuit 81 for the second Hall element group with the signs reversed. This is because the synthetic amplifier circuit 81 for the first Hall element group and the synthetic amplifier circuit 81 for the second Hall element group are at a position of 180 degrees around the rotation center axis of the rotor 106, and The N pole and S pole of the magnet 105 included in the rotor 106 are positioned 180 degrees around the rotation center axis of the rotor 106. Therefore, for example, when the synthetic amplifier circuit 81 for the first Hall element group described above detects the N pole, the synthetic amplifier circuit 81 for the second Hall element group detects the S pole. This is because the sign of the detected signal is reversed.

  In this manner, the synthesis amplifier circuit 81 synthesizes the detection values from the plurality of Hall elements included in the first Hall element group to increase the output value of the synthesis amplifier circuit 81 and the second Hall element. Detection values from a plurality of Hall elements included in the element group are combined to increase the output value of the combined amplifier circuit 81.

  Further, the synthesis amplifier circuit 81 generates an output value obtained by synthesizing detection values from a plurality of Hall elements included in the first Hall element group, and a plurality of Hall elements included in the second Hall element group. The output value of the synthesis amplifier circuit 81 is further increased by synthesizing the output value obtained by synthesizing the detected values with the opposite signs.

  The synthetic amplifier circuit 81 is, for example, the rotational position of the rotor 106 detected by the synthetic Hall element at the position indicated by reference numeral A1 in FIG. Is equivalent to or equivalent to outputting a signal indicating. In addition, since this synthetic Hall element outputs an output value obtained by synthesizing four Hall elements H1, H2, H3, and H4, the synthetic amplifier circuit 81 outputs a single Hall element. In contrast to this, a large signal can be output.

  As in the case of the first Hall element group and the second Hall element group, this synthetic amplifier circuit 82 is connected to, for example, the reference B1 in FIG. 23 by the third Hall element group and the fourth Hall element group. Is equivalent to or equivalent to outputting a signal indicating the rotational position of the rotor 106 detected by the synthetic Hall element located at a position of 135 degrees around the rotational center axis of the rotor 106. In addition, since this synthetic Hall element outputs an output value obtained by synthesizing four Hall elements H1, H2, H3, and H4, the synthetic amplifier circuit 82 outputs a single Hall element. In contrast to this, a large signal can be output.

  Further, as described above, the synthetic amplification circuit 81 is detected by, for example, the synthetic Hall element located at the position indicated by the symbol A1 in FIG. A signal indicating the rotation position of the rotor 106 is output, and the synthesis amplification circuit 82 is, for example, the position indicated by reference numeral B1 in FIG. 23 and at a position that is 135 degrees around the rotation center axis of the rotor 106. A signal indicating the rotational position of the rotor 106 detected by the synthetic Hall element is output. That is, the combined Hall element of the combined amplifier circuit 81 and the combined amplifier circuit 82 has a positional relationship of 90 degrees around the rotation center axis. Therefore, the synthetic amplifier circuit 81 and the synthetic amplifier circuit 82 can output an A-channel approximate sine wave output signal and a B-channel approximate sine wave output signal, which are 90 degrees out of phase, respectively.

  In this way, the synthesis amplifier circuit 81 synthesizes the detection signals detected by the plurality of Hall elements H1, H2, H3, and H4 so as to be the first synthesized magnetic detection element that detects the rotational position of the rotor 106. A channel approximate sine wave output signal is output. The synthetic amplification circuit 82 is a second synthetic magnetic detection element that detects the rotational position of the rotor 106, and has a predetermined angular position (for example, 90 degrees) with respect to the synthetic amplification circuit 81 around the rotation center axis. The detection signals detected by the plurality of Hall elements H1, H2, H3, and H4 are combined to output a B channel approximate sine wave output signal so as to be the second combined magnetic detection element.

  According to the third embodiment described above, between the Hall elements (Hall element H1 and Hall element H3, Hall element H2 and Hall element H4) that simply face the four Hall element signals as in the second embodiment. Rather than being amplified, all detection signals from the Hall element H1 to the Hall element H4 are used and input to the composite amplifier circuit 81 or 82, so that the offset voltage due to variations in sensitivity of each Hall element and changes in environmental temperature. Variation variation can be averaged.

  The signals of the Hall elements H1, H2, H3, and H4 are input to the synthesis amplifier circuit so as to add and subtract the signals of the opposing Hall elements having an angle of 180 degrees around the rotation center axis of the rotor 106. Yes. Therefore, even if the rotor 106 is eccentric, the rotation angle error due to this eccentricity can be canceled.

  By adopting such a method, the detection signal of the approximate sine wave generated by synthesis is increased, and as a result, the offset voltage fluctuation value is apparently decreased (relative to the detection signal). effective. For example, detection values are output from the respective Hall elements H1, H2, H3, and H4. The detection values are at a predetermined output level, and variations with respect to the output level cannot be ignored. However, as described above, the variation is relative to the value obtained by combining the detection values output from the plurality of Hall elements H1, H2, H3, and H4, that is, the output level of the detection value output from the combined Hall element. Therefore, the variation can be ignored. Therefore, the magnetic rotation angle detection device 100 according to the present embodiment can improve detection accuracy and achieve high accuracy and high resolution even when the outputs of the plurality of Hall elements vary.

  FIG. 24 is a diagram showing a configuration of a circuit for driving the Hall elements H1 to H4. The Hall elements H1 to H4 are each composed of two Hall elements (for example, the Hall element H1 and the Hall element H3, and the Hall element H2 and the Hall element H4) facing each other at 180 degrees around the rotation center axis of the rotor 106. It is driven by one constant current drive circuit. For example, as shown in FIG. 24, Hall element H1 and Hall element H3 are connected in series and driven by constant current drive circuit 101, and Hall element H2 and Hall element H4 are connected in series, and constant current drive circuit 102 is connected. It is driven by.

  By adopting such a drive circuit, for example, even when the current value of the constant current changes, the current values of the Hall elements facing each other influence each other. The change in the magnitude of the signal is the same, and there is a feature that the influence of the angle error is reduced when the two approximate sine wave signals are decomposed (multiplied) into smaller angles.

  There are two types of Hall element driving methods, a constant voltage driving method and a constant current driving method. The constant current driving method has a characteristic that variation in offset voltage variation due to changes in environmental temperature is reduced. is there. Therefore, by using the constant current driving method as described above, there is an effect that the variation in the offset voltage variation due to the change in the environmental temperature is smaller than when the constant voltage driving method is used.

  FIG. 25 is a configuration diagram in the case where the outputs of the combined amplifier circuits 81 and 82 shown in FIG. 20B are changed to the differential output system. The differential input-differential output type composite amplifier circuit 811 of FIG. 25 corresponds to the composite amplifier circuit 81 shown in FIG. 20B, and the differential input-differential output type composite amplifier circuit 821 of FIG. Corresponds to the synthetic amplifier circuit 82 shown in FIG. In FIG. 25, the same components as those in FIG. 20B are denoted by the same reference numerals, and only different points will be described.

  First, the configuration of the synthesis amplifier circuit 811 will be described. In the synthesis amplifier circuit 811, the synthesis unit 711 and the synthesis unit 712 are the same as the synthesis amplification circuit 81 shown in FIG. The output of the synthesis unit 711 is input as a subtraction signal to the addition / subtraction amplification circuit 714, and the output of the synthesis unit 712 is input to the addition / subtraction amplification circuit 715 as a subtraction signal. The power supply voltage V is input to the addition / subtraction amplification circuit 714 and the addition / subtraction amplification circuit 715 as an addition signal. The approximate sine wave output signal of the A (−) channel is output from the output terminal of the addition / subtraction amplification circuit 714, and the approximate sine wave output signal of the A (+) channel is output from the output terminal of the addition / subtraction amplification circuit 715.

  The output terminal of the addition / subtraction amplification circuit 714 and the output terminal of the addition / subtraction amplification circuit 715 are connected through a series connection of a resistor R51, a resistor R6, and a resistor R52. The input terminal to which the subtraction signal of the addition / subtraction amplification circuit 714 is input is connected to a connection point between the resistor R51 and the resistor R6 via the resistor R41. The input terminal to which the subtraction signal of the addition / subtraction amplification circuit 715 is input is connected to a connection point between the resistor R52 and the resistor R6 via the resistor R42. Since the combined amplifier circuits 811 and 821 function as a differential amplifier circuit in which each output is a differential output system, for example, the resistance values of the resistor R41 and the resistor R42 are the same, and the resistor R51 and the resistor R52 It is desirable that the resistance values of are the same.

  Next, the configuration of the synthesis amplifier circuit 821 will be described. Similar to the synthetic amplification circuit 82 and the synthetic amplification circuit 81 described with reference to FIG. 20B, the synthetic amplification circuit 821 is a method of connecting the synthetic amplification circuit 811 and the four Hall elements H1, H2, H3, and H4. Only the difference.

  Similarly to the synthesis amplification circuit 82 and the synthesis amplification circuit 81 described with reference to FIG. 20B, the B (−) channel output from the synthesis amplification circuit 821 and the A (−) output from the synthesis amplification circuit 811. ) The channel is a signal having a phase difference of 90 degrees. Further, the B (+) channel output from the synthesis amplifier circuit 821 and the A (+) channel output from the synthesis amplifier circuit 811 are signals having a phase difference of 90 degrees.

  The input of the composite amplifier circuits 811 and 821 described above with reference to FIG. 25 is the same as that of the composite amplifier circuits 81 and 82 of FIG. 20B, but the output is A (−) (or B (− )) Channel, two signals of the A (−) (or B (−)) channel and the A (+) (or B (+)) channel whose phase is inverted by 180 degrees are output.

  When the output method of the synthetic amplifier circuits 81 and 82 in FIG. 20B is changed to a differential output method like the synthetic amplifier circuits 811 and 821 in FIG. 25, noise components are superimposed on the differential output signal. Even so, by taking the difference between the two signals (A (−) and A (+) or B (−) and B (+)) in the receiving circuit (not shown), this noise component is reduced. It can be removed.

  In other words, since the two signals are 180 degrees out of phase, the magnitude of the signal is doubled before and after the difference between the two signals, but the noise component is an in-phase signal. Therefore, by taking the difference between the two signals in the receiving circuit, the noise component can be removed even when the noise component is superimposed on the differential output signal. Therefore, by using the above-described differential output method, a more reliable detection signal can be received and output to the side circuit.

  FIG. 26 is a configuration diagram showing a circuit configuration for detecting an abnormality in the Hall elements H1, H2, H3, and H4. The same components as those in FIG. 24 are denoted by the same reference numerals, description thereof will be omitted, and only differences will be described. In FIG. 26, the abnormality detection circuit 111 detects whether or not the current flowing through the hall elements H1, H2, H3, and H4 is appropriate.

  As shown in FIG. 26, the output terminal of the constant current drive circuit 101 is grounded via Hall elements H1 and H3 and a resistor R71 connected in series. The output terminal of the constant current drive circuit 102 is grounded via Hall elements H2 and H4 and a resistor R72 connected in series. A power supply voltage V is input to power supply terminals of the constant current drive circuit 101 and the constant current drive circuit 102.

  As described with reference to FIG. 24, since a constant current is output from the constant current driving circuit 101, a constant voltage is generated across the resistor R71. Specifically, a constant voltage is generated at the connection point between the resistor R71 and the Hall element H3. The abnormality detection circuit 111 measures the voltage generated at the resistor R72, that is, the voltage at the connection point between the resistor R71 and the Hall element H3, and determines whether or not the measured voltage is within a predetermined range. If it is not within the range, it is determined as abnormal.

  For example, if a current of 1 mA flows from the constant current drive circuit 101 and the resistance R71 is 100Ω, the voltage that is normally measured by the abnormality detection circuit 111 is 0.1V. If the measured voltage is 0.09 V or less or 0.11 V or more, the abnormality detection circuit 111 determines that an abnormality has occurred and outputs a signal indicating the abnormality. Thereby, the abnormality detection circuit 111 can detect, for example, an abnormality such as disconnection or short-circuit between the Hall elements H1 and H3, or an abnormality in the current value output from the constant current drive circuit 101.

  Similar to the constant current drive circuit 101, a constant current is also output from the constant current drive circuit 102, so that a constant voltage is generated across the resistor R72. As in the case of the resistor R71, the abnormality detection circuit 111 measures the voltage generated at the resistor R72, determines whether or not the measured voltage is within a predetermined range, and is not within the range. Is determined to be abnormal.

  In this way, the abnormality detection circuit 111 detects the abnormality of the Hall elements H1 and H3 and the constant current drive circuit 101 by measuring the voltage of the resistor R71, and measures the voltage of the resistor R72 to measure the Hall elements H2 and H4. Then, the abnormality of the constant current drive circuit 102 is detected. That is, the abnormality detection circuit 111 detects, for each set of Hall elements, a current that conducts two Hall elements that are set as a set of Hall elements, and an abnormality of a plurality of Hall elements based on the detected current, or An abnormality in the drive circuit that drives the plurality of Hall elements is detected.

  In addition, the abnormality detection circuit 111 outputs a signal indicating the detected abnormality to, for example, a host control device that controls the magnetic rotation angle detection device 100. As a result, even in the host control device, it is possible to detect, for example, an abnormality such as a disconnection or a short circuit or an abnormality in the drive circuit that drives the grouped Hall element for each grouped Hall element. .

  Here, although it has been described that one abnormality detection circuit 111 detects abnormality of all the hall element sets, this abnormality detection circuit 111 may be provided for each hall element group. .

  Each configuration described above with reference to FIGS. 24 to 26 can be applied not only to the third embodiment but also to the first embodiment and the second embodiment in the same manner, and the same effect can be obtained. Obtainable.

  According to the encoder according to the present embodiment described above, the following effects can be obtained.

  Since the Hall element is controlled by an analog switch (for example, the switching circuits 20-1 to 20-4), the temperature drift of the Hall element can be canceled, and a more accurate angle detection signal can be obtained. You can control.

  Since the second encoder 4 is decelerated by the power transmission device 2 and rotates at a low speed, the detection signal becomes a low-frequency sine wave signal or cosine wave signal. Therefore, since the control speed of the analog switch may be slow, a control resistant to noise can be configured.

  By controlling the analog switch control signal of the second encoder 4 with a signal control circuit mounted on the first encoder 3, it is possible to control with the control signal optimum for the frequency of the rotation detection signal of the second encoder 4. it can.

  By converting the output signal of the second encoder 4 to a differential output signal and subtracting it on the first encoder 3 side, noise on the way can be removed, and a more accurate rotation detection signal can be obtained. I can do it.

  By synchronizing the analog / digital conversion circuit (AD converter 201) mounted on the first encoder 3 side with the analog switch control signal at a certain ratio, the analog / digital conversion circuit can be used within a period other than noise caused by switching of the analog switch. Therefore, it is possible to obtain a highly accurate detection signal that is not affected by noise.

One of the first encoder 3 and the second encoder 4 may be a magnetic encoder as described above, and the other may be an optical encoder. For example, in the case of a magnetic encoder, if a magnetic field is generated due to disturbance, there is a possibility that position data cannot be detected normally. Even in such a case, the optical encoder can normally detect the position data.
Therefore, even when a magnetic field is generated due to disturbance, an encoder in which one of the first encoder 3 and the second encoder 4 is a magnetic encoder as described above and the other is an optical encoder is With the optical encoder, the position data can be normally detected as the whole encoder.

Also, in an environment where there are dust and oil droplets as an external environment, there is a possibility that the optical encoder cannot detect position data normally. Even in such a case, the position data can be normally detected with a magnetic encoder.
Therefore, even in an environment where dust or oil droplets exist as an external environment, one of the first encoder 3 and the second encoder 4 is a magnetic encoder as described above, and the other is an optical encoder. The encoder can detect position data normally by the magnetic encoder as a whole.

  Furthermore, since one of the first encoder 3 and the second encoder 4 is the magnetic encoder according to the above-described embodiment, the detection accuracy can be improved even when the output of the magnetic detection element varies. It is possible to improve and achieve high accuracy. Furthermore, even when there is a temperature change, the detection accuracy can be improved and high accuracy can be achieved.

Therefore, one of the first encoder 3 and the second encoder 4 is a magnetic encoder as described above, the other is an optical encoder, and this magnetic encoder is also used in the present embodiment described above. Even if a magnetic field is generated by a disturbance due to a magnetic encoder according to the form, even if there is dust or oil droplets as an external environment, the output of the magnetic detection element varies. Even if there is a case where there is a change in temperature, the encoder as a whole can detect position data normally, improve detection accuracy, and achieve high accuracy. .
Further, this encoder can function as a multi-rotation encoder while being battery-less.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within a scope not departing from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Motor, 2 ... Power transmission device, 3 ... 1st encoder, 4 ... 2nd encoder, 5 ... 2nd signal processing circuit, 6 ... 1st signal processing circuit, 8 ... Controller, 9 ... Communication line DESCRIPTION OF SYMBOLS 10 ... Input shaft, 11 ... Output shaft, 12 ... Communication line, 13 ... Setting control line, 14 ... Motor control line, 20-1-20-4 ... Switching circuit, 50 ... 2nd position data detection circuit, 51 ... second interpolation circuit, 52 ... second position detection circuit, 53 ... transmission signal generation output unit, 56, 66 ... transmission ratio information storage unit, 57, 67 ... first resolution storage unit, 58, 68 ... Second resolution storage unit 61... First position data detection circuit 62. Second position data correction circuit 63. Position data synthesis circuit 65 65 External communication circuit 81, 82, 811, 821. Circuit, 100 ... Magnetic rotation angle detection device, 101, DESCRIPTION OF SYMBOLS 02 ... Constant current drive circuit, 105 ... Magnet, 106 ... Rotor, 109 ... Board set, 111 ... Abnormality detection circuit, 112 ... Switching circuit control part, 200 ... Arithmetic circuit, 201 ... AD converter, 202 ... Arithmetic control part, 711, 712, 721, 722 ... Synthesizer, 713, 714, 715, 723, 724, 725 ... Addition / subtraction amplifier circuit, H1, H2, H3, H4 ... Hall element, n ... Transmission ratio, m ... Number of rotations, P1 ... First position data value, P2 ... second position data value, R2 ... second position data detection circuit 50 resolution

Claims (20)

A first-rotation type absolute encoder that outputs a first detection signal corresponding to an angular position of a rotated input shaft;
A second absolute position encoder that outputs a second detection signal corresponding to an angular position of an output shaft that is rotated at a predetermined transmission ratio according to the rotation of the input shaft;
First position data indicating an angular position of the input shaft is detected by first predetermined signal processing based on a first detection signal input from the first absolute position encoder. Position data detection circuit of
Second position data for detecting second position data indicating the angular position of the output shaft by a predetermined second signal processing based on a second detection signal input from the second absolute position encoder. Position data detection circuit of
A position data combining circuit that combines the first position data and the second position data to generate combined position data indicating an angular position within one rotation together with the multi-rotation amount of the input shaft;
With
The first absolute position encoder or the second absolute position encoder includes a rotor that rotates as the input shaft or the output shaft rotates, and a plurality of magnetic detection elements arranged around the rotor. A magnetic encoder, comprising a switching circuit for switching the connection between an input terminal for supplying power to the magnetic detection element and an output terminal for outputting the detection signal from the magnetic detection element for each magnetic detection element;
An encoder characterized by that. A switching control circuit that controls the switching circuit to periodically switch the connection between the input terminal and the output terminal of the magnetic detection element at a first time interval;
The encoder according to claim 1, further comprising: The first absolute position encoder or the second absolute position encoder;
A synthesis circuit that synthesizes a detection signal detected by the magnetic detection element and is switched by the switching circuit, and outputs the first detection signal or the second detection signal;
The encoder according to claim 2, further comprising: A conversion circuit that performs analog-to-digital conversion on the first detection signal or the second detection signal;
The encoder according to claim 2, further comprising: The conversion circuit includes:
After a second time shorter than the first time interval has elapsed since the switching control circuit switched the connection between the input terminal and the output terminal of the magnetic detection element, the first detection signal or the first Convert the detection signal of 2 to analog to digital,
The encoder according to claim 4. The first position data detection circuit or the second position data detection circuit is
The first position data or the second position data is detected based on an average of the first detection signal after the analog-digital conversion or an average of the second detection signal after the analog-digital conversion. To
The encoder according to claim 4 or 5, characterized by the above. The synthesis circuit is:
A first synthesis circuit that synthesizes detection signals detected by the mutually facing magnetic detection elements for each of the magnetic detection elements facing each other about the rotation center axis of the rotor among the plurality of magnetic detection elements; A second synthesis circuit;
The encoder according to any one of claims 3 to 6, further comprising: The synthesis circuit is:
A first synthesis circuit that synthesizes detection signals detected by the plurality of magnetic detection elements and outputs the first detection signal so as to be a first synthetic magnetic detection element that detects a rotational position of the rotor. When,
A second synthetic magnetic sensing element for detecting a rotational position of the rotor, wherein the second synthetic magnetic sensing element is located at a predetermined angular position with respect to the first synthetic magnetic sensing element about a rotational center axis of the rotor; A second combining circuit that combines the detection signals detected by the plurality of magnetic detection elements to output the second detection signal so as to be a combined magnetic detection element;
The encoder according to any one of claims 3 to 6, further comprising: Among the plurality of magnetic detection elements, a magnetic detection element included in a first region divided by a first plane including the rotation center axis is defined as a first magnetic detection element group, and is divided by the first plane. The magnetic detection elements included in the second region to be set as a second magnetic detection element group,
Among the plurality of magnetic detection elements, included in a third region divided by a second plane that includes the rotation center axis and that forms a predetermined angle with the first plane. And the magnetic detection elements included in the fourth region divided by the second plane as the fourth magnetic detection element group.
The first synthesis circuit includes:
Combining detection signals respectively detected by the first magnetic detection element group and the second magnetic detection element group;
The second synthesis circuit includes:
Combining detection signals respectively detected by the third magnetic detection element group and the fourth magnetic detection element group;
The encoder according to claim 8. The plurality of magnetic detection elements respectively output a first detection signal and a second detection signal as the detection signals,
The first synthesis circuit includes:
The first detection signal output from the magnetic detection element of the first magnetic detection element group and the second detection signal output from the magnetic detection element of the second magnetic detection element group respectively. A third synthesizing circuit that synthesizes as a detection signal of 3;
The second detection signals output from the magnetic detection elements of the first magnetic detection element group and the first detection signals output from the magnetic detection elements of the second magnetic detection element group respectively. A fourth synthesizing circuit that synthesizes as the four detection signals;
A first differential amplifier circuit that generates the first detection signal based on a difference between the third detection signal and the fourth detection signal;
The encoder according to claim 9, further comprising: The second synthesis circuit includes:
The first detection signal output from the magnetic detection element of the third magnetic detection element group and the second detection signal output from the magnetic detection element of the fourth magnetic detection element group respectively. A fifth synthesizing circuit that synthesizes as a detection signal of 5;
The second detection signal output from the magnetic detection element of the third magnetic detection element group and the first detection signal output from the magnetic detection element of the fourth magnetic detection element group are A sixth synthesizing circuit for synthesizing the detection signals of 6;
A second differential amplifier circuit that generates the second combined signal based on a difference between the fifth detection signal and the sixth detection signal;
The encoder according to claim 10, further comprising: The plurality of magnetic detection elements are composed of two magnetic detection elements that are arranged opposite to each other with respect to the rotation center axis of the rotor. It is configured,
The encoder according to any one of claims 1 to 11, characterized in that: The plurality of magnetic detection elements are:
Power is connected in series for each of the two magnetic detection elements in the set of magnetic detection elements,
The encoder according to claim 12. A current that conducts two magnetic detection elements that constitute the magnetic detection element is detected for each set of the magnetic detection elements, and abnormality of the plurality of magnetic detection elements is detected based on the detected current. Anomaly detection circuit,
The encoder according to claim 12 or 13, further comprising: The number of rotations of the input shaft is counted, and the counted number of rotations is corrected in advance based on the counted number of rotations and the first position data detected by the first position data detection circuit. A second position data correction circuit to correct by
Have
The position data synthesis circuit includes:
Combining the rotation quantity corrected by the second position data correction circuit and the first position data detected by the first position data detection circuit to generate the combined position data;
The encoder according to any one of claims 1 to 12, characterized in that: In association with the counted number of rotations and the first position data detected by the first position data detection circuit, a correction value storage unit in which a correction value for correcting the counted number of rotations is stored in advance is provided. ,
The second position data correction circuit comprises:
A correction value associated with the counted number of rotations and the first position data detected by the first position data detection circuit is read from the correction value storage unit, and the read correction value is counted as the counted rotation. Add to the quantity to correct the counted rotation quantity,
The encoder according to claim 15. The first synthesis circuit outputs the first detection signal as a differential signal,
The second synthesis circuit outputs the second detection signal as a differential signal.
The encoder according to any one of claims 7 to 16, characterized in that: The magnetic detection element is a Hall element.
The encoder according to any one of claims 1 to 17, characterized in that: One of the first absolute position encoder or the second absolute position encoder is a magnetic encoder,
The other of the first absolute position encoder or the second absolute position encoder is an optical encoder.
The encoder according to any one of claims 1 to 18, characterized in that: A first absolute position output step of outputting a first detection signal corresponding to the angular position of the input shaft rotated by a first absolute position encoder which is a one-rotation type absolute encoder;
A second absolute position encoder, which is a one-rotation type absolute encoder, outputs a second detection signal corresponding to the angular position of the output shaft rotated at a predetermined transmission ratio according to the rotation of the input shaft. Absolute position output process,
Based on the first detection signal input from the first absolute position encoder by the first position data detection circuit, a first signal processing that is determined in advance indicates the angular position of the input shaft. A first position data detecting step of detecting position data of one;
The second position data detection circuit indicates the angular position of the output shaft by a predetermined second signal processing based on the second detection signal input from the second absolute position encoder. A second position data detecting step for detecting position data of 2;
A position data synthesis circuit that synthesizes the first position data and the second position data by a position data synthesis circuit, and generates synthesized position data indicating an angular position within one rotation together with the multi-rotation amount of the input shaft. Process,
Have
The first absolute position encoder or the second absolute position encoder includes a rotor that rotates as the input shaft or the output shaft rotates, and a plurality of magnetic detection elements that are arranged around the rotor. A magnetic encoder,
A switching step of switching a connection between an input terminal for supplying power to the magnetic detection element and an output terminal for outputting the detection signal from the magnetic detection element for each magnetic detection element by a switching circuit;
And a signal processing method.

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