JP7085851B2 - Position detection device and position detection method - Google Patents

Description

The present invention relates to a position detection device that detects the position of a magnetic scale that moves relative to each other by a magnetic sensor device, and a position detection method of the position detection device.

As a position detection device that outputs an absolute value, a magnetic sensor device and a magnetic scale that moves relative to the magnetic sensor device are known. The magnetic scale includes an absolute track in which an absolute pattern is formed at a predetermined pitch in a relative moving direction, and an incremental track in which an incremental pattern is formed at a pitch corresponding to the absolute pattern in parallel with the absolute track. The magnetic sensor device has an absolute value output unit that reads the absolute track and outputs the absolute value, an incremental signal output unit that reads the incremental track and outputs a periodic incremental signal, and a magnetic scale based on the absolute value and the incremental signal. It is provided with a calculation unit for calculating the absolute position of. The absolute value output unit includes a magnetic sensory element for acquiring an absolute signal for reading the absolute pattern, and the incremental signal output unit includes a magnetic sensory element for acquiring an incremental signal for reading the incremental pattern.

The absolute pattern is an arrangement of a magnetized region and a non-magnetized region in a non-repeating pattern with a constant pitch. The magnetic sensing element for acquiring the absolute signal includes a plurality of magnetoresistive elements whose magnetic sensing direction is directed to the relative moving direction. The plurality of magnetoresistive elements are arranged in the relative movement direction at the same pitch as the non-repetitive pattern, and detect a magnetic field in a plurality of regions when the magnetic scale and the magnetic sensor move relative to each other. The absolute value output unit is a multi-bit M-series irregularity in which the logical value in the region where the signal output from each magnetoresistive element is equal to or higher than a predetermined threshold value is 1 and the logical value is 0 in a region where the signal does not exceed a predetermined threshold value. Output a circular random code. The calculation unit calculates the absolute position of the magnetic scale or the magnetic sensor device based on the phase and absolute value of the incremental signal.

The position detection device of Patent Document 1 has an absolute track on the absolute track in order to accurately acquire the output near the boundary of each pattern region (magnetized region or non-magnetized region) of the absolute pattern existing at a predetermined pitch. It includes a first track having a pattern and a second track having a magnetized pattern provided in parallel with the first track and having a magnetized region and a non-magnetized region arranged opposite to the absolute pattern. Further, as the absolute value output unit, a first signal output unit that reads the absolute pattern of the first track and outputs the first signal, and a second signal output unit that reads the magnetism pattern of the second track and outputs the second signal. It is equipped with a department. The calculation unit acquires an absolute value based on the differential signal between the first signal and the second signal, and calculates the absolute position based on the acquired absolute value and the value (phase) of the incremental signal. In the configuration of Patent Document 1, the differential signal between the first signal and the second signal is equal to or higher than the reference potential in the magnetized region of the absolute pattern and equal to or lower than the reference potential in the non-magnetized region. Therefore, if the reference potential is used as the threshold value, the absolute value near the boundary between the magnetized region and the non-magnetized region can be accurately obtained in the pattern portion of the absolute pattern in which the magnetized region and the non-magnetized region are adjacent to each other.

Japanese Unexamined Patent Publication No. 2017-102089

In the technique of Patent Document 1, in the pattern portion of the absolute pattern in which the magnetized region and the magnetized region are adjacent to each other, the differential signal becomes the reference potential at the boundary between the two pattern regions (magnetized region and magnetized region). Therefore, when the reference potential is used as the threshold value, the absolute value may not be obtained accurately. If an accurate absolute value cannot be obtained, it will be difficult for the calculation unit to calculate the absolute position.

In view of the above points, an object of the present invention is to provide a position detecting device capable of calculating an absolute position based on an accurate absolute value. Another object of the present invention is to propose a position detection method of a position detection device capable of calculating an absolute position based on an accurate absolute value.

In order to solve the above problems, in the present invention, the absolute track having an absolute pattern in which the magnetized region and the non-magnetized region are arranged at the first pitch, and the magnetized region and the non-magnetized region alternate with each other. A magnetic scale having an arranged incremental pattern and having an incremental track provided in parallel with the absolute track, an absolute value output unit that reads the absolute track of the magnetic scale that moves relative to each other and outputs an absolute value, and a relative movement. An incremental signal output unit that reads the incremental track of the magnetic scale and outputs a periodic incremental signal that changes from zero to a predetermined maximum value, and calculates an absolute position based on the absolute value and the incremental signal. In a position detecting device having a magnetic sensor device including a calculation unit, the absolute track is a second of the first track having the absolute pattern and half of the first pitch in a movement direction relative to the first track. A second track having the absolute pattern shifted by two pitches and provided in parallel with the first track is provided, and the absolute value output unit reads the first track and outputs the first absolute value. The first absolute value output unit is provided with a first absolute value output unit and a second absolute value output unit that reads the second track and outputs the second absolute value. The value output unit is set at the time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time of the first absolute value output in which the new absolute value is output. The calculation unit uses the first absolute value to calculate the absolute position in the first period from the time when the incremental signal becomes 0 to the time when the incremental signal reaches the central value between zero and the maximum value. In the second period from the time when the incremental signal reaches the median value to the time when the incremental signal reaches the maximum value, the second absolute value is used to calculate the absolute position, and the incremental signal correction unit corrects the incremental signal. The incremental signal correction unit has 1/4 of the first pitch from the time of the first absolute value output. The time point at which the magnetic scale and the magnetic sensor device move relative to each other by the pitch is set as the reference increment start time point, and the deviation amount in which the incremental start time point of the actual incremental signal is deviated from the reference increment start time point is acquired. A corrected incremental signal that corrects the phase shift of the incremental signal is generated based on the deviation amount, and the calculation unit uses the corrected incremental signal to calculate the absolute position, and the corrected incremental signal becomes 0. The first absolute value is used to calculate the absolute position from a time point until the corrected incremental signal reaches the center value between zero and the maximum value, and the correction is made from the time when the corrected incremental signal reaches the center value. The second absolute value is used for calculating the absolute position until the incremental signal reaches the maximum value, and the incremental signal correction unit has a value in which the first absolute value and the second absolute value are different from the same value. The first value of the incremental signal at the first time point changed to, and the incremental signal at the second time point in which the first absolute value and the second absolute value return to the same value after the first time point. It is characterized in that the deviation amount is acquired based on the second value .

According to the present invention, in the absolute track, the absolute pattern of the first track for acquiring the first absolute value and the absolute pattern of the second track for acquiring the second absolute value are a magnetic scale and a magnetic sensor. It is off by a half pitch (second pitch) in the relative movement direction with the device. Further, the incremental signal output by the incremental signal output unit includes a magnetic scale and a magnetic sensor device for only 1/4 pitch of the first pitch from the time of the first absolute value output in which the first absolute value output unit outputs a new absolute value. Starts incrementing from the point when is moved relative to each other. Further, the calculation unit that calculates the absolute position based on the absolute value and the incremental signal uses the first absolute value for calculating the absolute position in the first period from the start of incrementing the incremental signal to the time when the incremental signal reaches the median. In the second period from the time when the incremental signal reaches the median value to the time when the incremental signal reaches the maximum value, the second absolute value is used for calculating the absolute position. As a result, when calculating the absolute position, the calculation unit can use the first absolute value obtained by detecting the boundary of each pattern region existing for each first pitch in the absolute pattern of the first track. Therefore, the second absolute value obtained by detecting the boundary of each pattern region existing at each first pitch in the absolute pattern of the second track is not used. Therefore, the calculation unit can use an accurate absolute value (first absolute value or second absolute value) for calculating the absolute position. By doing so, the increment signal actually output from the incremental signal output unit starts incrementing due to the fact that the installation posture of the magnetic sensor device is tilted with respect to the relative movement direction of the magnetic scale. When the time point shifts from the predetermined reference increment start time point, the incremental signal correction unit generates a corrected incremental signal that corrects the phase shift of the incremental signal based on the shift amount. Further, the calculation unit uses the correction incremental signal to calculate the absolute position. As a result, the absolute position calculated by the calculation unit becomes a correct value. By doing so, the amount of deviation can be easily obtained, so that the incremental signal correction unit can easily generate the corrected incremental signal.

In the present invention, the incremental track may include an incremental pattern in which N poles and S poles are alternately magnetized at the second pitch in the relative moving direction. By doing so, it is easy to match the period in which the absolute value is acquired with the period in which the incremental signal is acquired.

Further, the present invention provides an absolute track having an absolute pattern in which magnetized regions and non-magnetized regions are arranged at the first pitch, and an incremental pattern in which magnetized regions and non-magnetized regions are alternately arranged. An absolute value output that reads the absolute track of the magnetic scale that moves relative to the magnetic scale that has an incremental track provided in parallel with the absolute track and outputs the absolute value.
Based on the force unit, the incremental signal output unit that reads the incremental track of the magnetic scale that moves relative to each other and outputs a periodic incremental signal that changes from zero to a predetermined maximum value, and the absolute value and the incremental signal. In a position detecting device including a magnetic sensor device including a calculation unit for calculating an absolute position, the absolute track is the first track having the absolute pattern and the first track in a movement direction relative to the first track. The absolute value output unit has a second track provided in parallel with the first track and has the absolute pattern deviated by the second pitch by half of the pitch, and the absolute value output unit reads the first track and first. A first absolute value output unit that outputs an absolute value and a second absolute value output unit that reads the second track and outputs a second absolute value are provided, and the increment start time point at which the incremental signal starts incrementing is , Set at the time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time when the first absolute value output unit outputs a new absolute value. In the first period from the time when the incremental signal becomes 0 to the time when the incremental signal reaches the center value between zero and the maximum value, the calculation unit calculates the absolute position. In the second period from the time when the incremental signal reaches the median value to the time when the incremental signal reaches the maximum value, the second absolute value is used to calculate the absolute position, and the incremental signal is corrected. The incremental signal correction unit has an incremental signal correction unit, and the incremental signal correction unit is based on a time point when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time point of the first absolute value output. As the increment start time point, a correction incremental is obtained by acquiring a deviation amount in which the incremental start time point of the actual incremental signal is deviated from the reference increment start time point, and correcting the phase shift of the incremental signal based on the deviation amount. The signal is generated, and the calculation unit uses the correction incremental signal to calculate the absolute position, and the correction ink. From the time when the remental signal becomes 0 until the corrected incremental signal reaches the median of zero and the center of the maximum value, the first absolute value is used for calculating the absolute position, and the corrected incremental signal is the median. The second absolute value is used for calculating the absolute position from the time when the corrected incremental signal reaches the maximum value, and the incremental signal correction unit has the first absolute value and the second absolute value. The third value of the incremental signal at the third time point that changed from a different value to the same value, and the fourth time point when the first absolute value and the second absolute value return to different values after the third time point. It is characterized in that the deviation amount is acquired based on the fourth value of the incremental signal of. By doing so, the amount of deviation can be easily obtained, so that the incremental signal correction unit can easily generate the corrected incremental signal.

Next, the present invention has an absolute track having an absolute pattern in which the magnetized region and the non-magnetized region are arranged at the first pitch, and an incremental pattern in which the magnetized region and the non-magnetized region are alternately arranged. A magnetic scale having an incremental track provided in parallel with the absolute track, an absolute value output unit that reads the absolute track of the magnetic scale that moves relative to each other and outputs an absolute value, and the magnetism that moves relative to each other. It has a magnetic sensor device including an incremental signal output unit that reads the incremental track of the scale and outputs a periodic incremental signal that changes from zero to a predetermined maximum value, and is absolute based on the absolute value and the incremental signal. In the position detection method of the position detecting device for calculating the position, the first track having the absolute pattern and the second track, which is half of the first pitch in the relative movement direction with respect to the first track, are previously used as the absolute track. It has the absolute pattern with a pitch shift, and includes a second track provided in parallel with the first track, and as the absolute value output unit, reads the first track and outputs the first absolute value. The first absolute value output unit is provided with a first absolute value output unit and a second absolute value output unit that reads the second track and outputs a second absolute value, and sets an increment start time point at which the incremental signal starts incrementing. The magnetic scale and the magnetic sensor device are set at a time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time when the value output unit outputs a new absolute value from the first absolute value. In the first period from the time when the incremental signal becomes 0 to the time when the incremental signal reaches the center value between zero and the center of the maximum value, the first absolute value is used for calculating the absolute position, and the incremental signal is the center. In the second period from the time when the value is reached until the incremental signal reaches the maximum value, the second absolute value is used for calculating the absolute position, and 1 / of the first pitch from the time when the first absolute value is output. The reference is defined as the reference increment start time when the magnetic scale and the magnetic sensor device move relative to each other by 4 pitches. An amount of deviation in which the actual incremental start time of the incremental signal is deviated from the increment start time is acquired, and a corrected incremental signal is generated in which the phase shift of the incremental signal is corrected based on the deviation amount, and the absolute signal is generated. The corrected incremental signal is used for calculating the position, and the first absolute position is calculated from the time when the corrected incremental signal becomes 0 until the corrected incremental signal reaches the median center of zero and the maximum value. Using the absolute value, the second absolute value is used to calculate the absolute position from the time when the corrected incremental signal reaches the median until the corrected incremental signal reaches the maximum value, and the first absolute value is used. The first value of the incremental signal at the first time point when the second absolute value changes from the same value to a different value, and the first absolute value and the second absolute value after the first time point are It is characterized in that the deviation amount is acquired based on the second value of the incremental signal at the second time point when the value returns to the same value .

According to the present invention, in the absolute track, the absolute pattern of the first track for acquiring the first absolute value and the absolute pattern of the second track for acquiring the second absolute value are a magnetic scale and a magnetic sensor. It is off by a half pitch (second pitch) in the relative movement direction with the device. Further, the incremental signal is incremented from the time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time when the first absolute value is output. When calculating the absolute position, the first absolute value is used to calculate the absolute position in the first period from the start of incrementing the incremental signal until the incremental signal reaches the median, and the incremental signal becomes the median. In the second period from the time when the incremental signal reaches the maximum value, the second absolute value is used for calculating the absolute position. Therefore, when calculating the absolute position, the first absolute value obtained by detecting the boundary of each pattern region existing for each first pitch in the absolute pattern of the first track is not used, and the second is not used. The second absolute value obtained by detecting the boundary of each pattern region existing for each first pitch in the absolute pattern of the track is not used either. Therefore, an accurate absolute value (first absolute value or second absolute value) can be obtained, and the absolute position can be reliably calculated. By doing so, the increment signal actually output from the incremental signal output unit starts incrementing due to the fact that the installation posture of the magnetic sensor device is tilted with respect to the relative movement direction of the magnetic scale. When the time point deviates from the predetermined reference increment start time point, a corrected incremental signal that corrects the phase shift of the incremental signal is generated based on the amount of the deviated time, and the corrected incremental signal is used to calculate the absolute position. Is used. Therefore, the absolute position calculated by the calculation unit is a correct value. By doing so, the amount of deviation can be easily obtained, so that the correction incremental signal can be easily generated.

In the present invention, the incremental track may be provided with an incremental pattern in which N poles and S poles are alternately magnetized at the second pitch in the relative moving direction. By doing so, it is easy to match the period in which the absolute value is acquired with the period in which the incremental signal is acquired.

Further, the present invention provides an absolute track having an absolute pattern in which magnetized regions and non-magnetized regions are arranged at the first pitch, and an incremental pattern in which magnetized regions and non-magnetized regions are alternately arranged. A magnetic scale having an incremental track provided in parallel with the absolute track, an absolute value output unit that reads the absolute track of the magnetic scale that moves relative to each other and outputs an absolute value, and the magnetic scale that moves relative to each other. It has a magnetic sensor device provided with an incremental signal output unit that reads the incremental track and outputs a periodic incremental signal that changes from zero to a predetermined maximum value, and has an absolute position based on the absolute value and the incremental signal. In the position detection method of the position detecting device for calculating the above, the first track having the absolute pattern and the second pitch, which is half of the first pitch in the relative movement direction with respect to the first track, are previously used as the absolute track. A second track having the displaced absolute pattern and provided in parallel with the first track, and as the absolute value output unit, the first track is read and the first absolute value is output. The first absolute value is provided with a 1 absolute value output unit and a second absolute value output unit that reads the second track and outputs a second absolute value, and sets an increment start time point at which the incremental signal starts incrementing. It is set at the time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time when the output unit outputs a new absolute value, and the incremental value is described. In the first period from the time when the signal becomes 0 to the time when the incremental signal reaches the center value between zero and the maximum value, the first absolute value is used for calculating the absolute position, and the incremental signal is the center value. In the second period from the time when the mark becomes Only the pitch with the magnetic scale
The time point at which the magnetic sensor device moves relative to the magnetic sensor device is set as the reference increment start time point, and the deviation amount at which the incremental start time point of the actual incremental signal is deviated from the reference increment start time point is acquired, and the deviation amount is obtained based on the deviation amount. A corrected incremental signal that corrects the phase shift of the incremental signal is generated, the corrected incremental signal is used for calculating the absolute position, and the corrected incremental signal becomes zero and the maximum from the time when the corrected incremental signal becomes 0. The first absolute value is used to calculate the absolute position until the center value of the center of the values is reached, and from the time when the corrected incremental signal reaches the center value until the corrected incremental signal reaches the maximum value. The second absolute value is used to calculate the absolute position , and the third value of the incremental signal at the third time point in which the first absolute value and the second absolute value change from different values to the same value, and the above-mentioned It is characterized in that the deviation amount is acquired based on the fourth value of the incremental signal at the fourth time point in which the first absolute value and the second absolute value return to different values after the third time point. By doing so, the amount of deviation can be easily obtained, so that the correction incremental signal can be easily generated.

According to the present invention, the absolute value referred to by the calculation unit at the start of increment when the incremental signal becomes zero is acquired by detecting the boundary of each pattern region existing at each first pitch in the absolute pattern of the first track. It is not obtained by detecting the boundary of each pattern region existing at each first pitch in the absolute pattern of the second track. Therefore, an accurate absolute value (first absolute value or second absolute value) can be obtained, and the absolute position can be reliably calculated.

It is explanatory drawing of the magnetic encoder device to which this invention is applied. It is explanatory drawing of the magnetic track of a magnetic scale and the sensor board of a magnetic sensor device. It is a block diagram of the control system of a magnetic encoder device. It is explanatory drawing of each signal and value acquired by a magnetic sensor device. It is a flowchart of the calculation operation of an absolute position. It is a block diagram of the control system of the magnetic encoder device of a modification. It is explanatory drawing of each signal and value acquired by the magnetic sensor device of a modification. It is a flowchart of the calculation operation of the absolute position of a modification.

Hereinafter, a magnetic encoder device according to an embodiment of the position detection device to which the present invention is applied will be described with reference to the drawings.

FIG. 1 is an explanatory diagram of a magnetic encoder device to which the present invention is applied. FIG. 2A is an explanatory diagram of a magnetic track provided on the magnetic scale, and FIG. 2B is an explanatory diagram of a sensor substrate of a magnetic sensor device that reads the magnetic track.

As shown in FIG. 1, the magnetic encoder device 1 (position detection device) of this example includes a magnetic scale 2 and a magnetic sensor device 3 for reading the magnetic scale 2. The magnetic scale 2 includes a magnetic track 5 that extends to the relative movement method of the magnetic scale 2 and the magnetic sensor device 3. The magnetic sensor device 3 detects a change in the magnetic field formed on the surface of the magnetic scale 2 when the magnetic scale 2 moves relative to the magnetic scale 2, and outputs the absolute moving position of the magnetic scale 2 or the magnetic sensor device 3. In the following description, the relative movement direction between the magnetic scale 2 and the magnetic sensor device 3 is the X direction, and the orthogonal direction orthogonal to the X direction is the Y direction.

The magnetic sensor device 3 includes a holder 7 made of a non-magnetic material and a cable 8 extending from the holder 7. The holder 7 includes a facing surface 9 facing the magnetic scale 2. An opening 9a is provided on the facing surface 9. A magnetic sensor 10 is arranged in the opening 9a. As shown in FIG. 2B, the magnetic sensor 10 includes a sensor substrate 11 such as a silicon substrate or a ceramic grace substrate, and a plurality of magnetic sensing elements 12 formed on the substrate surface of the sensor substrate 11 facing the magnetic scale 2. , 13, and. The magnetic sensing elements 12 and 13 have, for example, a magnetoresistive element provided with a permalloy film as a magnetic sensing film. The magnetic sensing elements 12 and 13 face each other with the magnetic scale 2 via a predetermined gap.

In the magnetic encoder device 1, one of the magnetic scale 2 and the magnetic sensor device 3 is arranged on the side of the fixed body, and the other is arranged on the side of the moving body. In this example, the magnetic scale 2 is arranged on the side of the moving body, and the magnetic sensor device 3 is arranged on the side of the fixed body.

(Magnetic scale)
As shown in FIG. 2A, the magnetic track 5 includes an absolute track 15 extending in the X direction, which is a relative movement direction between the magnetic scale 2 and the magnetic sensor device 3, and an incremental track 16. The absolute track 15 and the incremental track 16 are provided in parallel and extend in parallel in the X direction. The absolute track 15 includes a first absolute track 21 (first track) and a second absolute track 22 (second track) provided in parallel. The incremental track 16 includes a first incremental track 17 and a second incremental track 18 provided in parallel.

The first absolute track 21 has a first absolute pattern 21a formed by the first pitch P1. The first absolute pattern 21a is an arrangement of a magnetized magnetized region and a non-magnetized non-magnetized region in a non-repeating pattern (pseudo-random pattern) of the first pitch P1. Each magnetized region constituting one pattern region has an N pole and an S pole in the X direction. The second absolute track 22 of the absolute track 15 has a second absolute pattern 22a displaced by a second pitch P2, which is half of the first pitch P1 in the relative movement direction with respect to the first absolute pattern 21a of the first absolute track 21. In this example, the first pitch P1 is 0.8 mm and the second pitch P2 is 0.4 mm.

Here, the first absolute pattern 21a and the second absolute pattern 22a are irregular M-sequences indicating absolute positions on the magnetic scale 2 by the arrangement of the magnetized region and the non-magnetized region in the pattern region for continuous n pitches. Represents a circular random number code. More specifically, when the magnetized region is set to the logical value of 1 and the non-magnetized region is set to the logical value of 0, an irregularly circulating random number of M series is obtained by an array of 1 and 0 in continuous n regions. The code is shown as a value. In this example, n is 6.

The first incremental track 17 has a first incremental pattern 17a formed by a second pitch P2 which is half of the first pitch P1. The first incremental pattern 17a is obtained by alternately magnetizing the N pole and the S pole in the X direction at the second pitch P2. The second incremental track 18 has a second incremental pattern 18a formed by the second pitch P2. The second incremental pattern 18a is obtained by alternately magnetizing the N pole and the S pole in the X direction at the second pitch P2, and the order of magnetism of the N pole and the S pole is opposite to that of the first incremental pattern 17a. Is. Therefore, in the Y direction, the north pole of the first incremental pattern 17a and the south pole of the second incremental pattern 18a are adjacent to each other. Further, in the Y direction, the S pole of the first incremental pattern 17a and the N pole of the second incremental pattern 18a are adjacent to each other.

(Magnetic sensor device)
As shown in FIG. 2B, the sensor substrate 11 of the magnetic sensor 10 has a magnetic sensing element 12 for acquiring an absolute signal, a magnetic sensing element 13 for acquiring an incremental signal, and a magnetic sensing element 13 for acquiring an absolute signal on a substrate surface facing the magnetic scale 2. To prepare for. The magnetic sensing element 12 for acquiring the absolute signal and the magnetic sensing element 13 for acquiring the incremental signal are arranged in the Y direction.

The magnetic sensing element 12 for acquiring the absolute signal includes a first magnetic resistance pattern 31 for acquiring the first absolute signal from the first absolute pattern 21a of the first absolute track 21 and a second absolute pattern of the second absolute track 22. A second magnetic resistance pattern 32 for acquiring a second absolute signal from 22a is provided. The first magnetoresistance pattern 31 and the second magnetoresistance pattern 32 are arranged in the Y direction and extend in parallel in the X direction. When the magnetic sensor device 3 faces the magnetic scale 2, the first magnetoresistive pattern 31 faces the first absolute track 21, and the second magnetoresistive pattern 32 faces the second absolute track 22.

The first magnetic resistance pattern 31 and the second magnetic resistance pattern 32 each include a plurality of magnetic resistance elements arranged in the X direction in a posture in which the magnetic sensing direction is directed in the X direction. The plurality of magnetoresistive elements are arranged at the first pitch P1. The first magnetoresistive pattern 31 sequentially detects the magnetic fields of each of the six regions of the first absolute pattern 21a continuous in the X direction, and outputs the first absolute signals of the six systems. Similarly, the second magnetoresistance pattern 32 sequentially detects the magnetic fields of the respective regions of the second absolute pattern 22a continuous in the X direction, and outputs the second absolute signal of six systems.

The magnetic resistance element 13 for acquiring the incremental signal includes a magnetoresistance pattern 34 (+ a) for SIN + signal detection, a magnetoresistance pattern 34 (+ b) for COS + signal detection, and a magnetoresistance pattern 34 (−a) for SIN− signal detection. ), COS-Magnetic resistance pattern 34 (-b) for signal detection. In this embodiment, the magnetoresistance pattern 34 (+ a) for SIN + signal detection and the magnetoresistance pattern 34 (−b) for COS − signal detection are arranged in the X direction. Further, the reluctance pattern 34 (+ b) for COS + signal detection and the reluctance pattern 34 (-a) for SIN- signal detection are arranged in the X direction. The reluctance pattern 34 (+ a) for SIN + signal detection and the reluctance pattern 34 (+ b) for COS + signal detection are adjacent to each other in the Y direction. The reluctance pattern 34 (-b) for COS-signal detection and the magnetoresistance pattern 34 (-a) for SIN- signal detection are adjacent to each other in the Y direction. When the magnetic sensor device 3 is opposed to the magnetic scale 2, the reluctance pattern 34 (+ a) for SIN + signal detection and the reluctance pattern 34 (-b) for COS-signal detection are the first incremental track 17. The reluctance pattern 34 (+ a) for SIN + signal detection and the reluctance pattern 34 (−b) for COS − signal detection face the second incremental track 18.

Here, when the magnetic scale 2 moves with respect to the magnetic sensor device 3, the magnetic resistance pattern 3
The signal output from 4 (+ a) and the signal output from the magnetoresistance pattern 34 (+ b) have a phase difference of 90 ° from each other. The signal output from the magnetoresistance pattern 34 (−a) and the signal output from the magnetoresistance pattern 34 (−b) have a phase difference of 90 ° from each other. The signal output from the magnetoresistance pattern 34 (+ a) and the signal output from the magnetoresistance pattern 34 (−a) have a phase difference of 180 °. The signal output from the magnetoresistance pattern 34 (+ b) and the signal output from the magnetoresistance pattern 34 (−b) have a phase difference of 180 °.

FIG. 3 is a schematic block diagram showing a control system of the magnetic encoder device 1. FIG. 4 is an explanatory diagram of each signal and value acquired by the magnetic sensor device 3 by reading the magnetic scale 2. FIG. 4A is an explanatory diagram of an M-sequence irregularly circular random number code acquired by the first absolute value acquisition unit and the second absolute value acquisition unit. FIG. 4B is an explanatory diagram of the absolute value output by the first absolute value output unit and the second absolute value output unit based on the irregularly circulating random number code of the M sequence. FIG. 4C is an explanatory diagram of an incremental signal output by the incremental signal output unit. FIG. 5 is a flowchart of the absolute position calculation operation.

As shown in FIG. 3, the control system of the magnetic sensor device 3 includes an arithmetic processing unit 40 including a CPU, ROM, RAM, and the like. In this example, the arithmetic processing unit 40 is mounted on the sensor board 11. A magnetic sensing element 12 for acquiring an absolute signal and a magnetic sensing element 13 for acquiring an incremental signal are connected to the input side of the arithmetic processing unit 40. The arithmetic processing unit 40 includes an absolute value acquisition unit 41, an incremental signal acquisition unit 42, and a calculation unit 44 for calculating an absolute position. The absolute value acquisition unit 41 includes a first absolute value acquisition unit 45 and a second absolute value acquisition unit 46.

Here, the first magnetic resistance pattern 31 of the magnetic sensing element 12 for acquiring the absolute signal and the first absolute value acquisition unit 45 read the first absolute track 21 and output the first absolute value ABS1. The output unit 37 is configured. The second magnetic resistance pattern 32 and the second absolute value acquisition unit 46 of the magnetic sensing element 12 for acquiring the absolute signal are the second absolute value output unit 38 that reads the second absolute track 22 and outputs the second absolute value ABS2. To configure. The magnetic sensory element 13 for acquiring the incremental signal and the incremental signal acquisition unit 42 constitute an incremental signal output unit 39 that reads the incremental track 16 and outputs the incremental signal INC.

As shown in FIG. 4A, the first absolute value acquisition unit 45 first has a 6-bit first irregularly circulating random number based on the first absolute signals of the six systems output from the first magnetoresistive pattern 31. Get the code CORD1. Next, as shown in FIG. 4B, the first absolute value acquisition unit 45 replaces the acquired first irregularly circulating random number code CORD1 with a sequence of integers to acquire the first absolute value ABS1. When the first absolute value acquisition unit 45 acquires the first absolute value ABS1, the first absolute value output unit 37 outputs the first absolute value ABS1.

As shown in FIG. 4A, the second absolute value acquisition unit 46 has a 6-bit second irregularly circulating random number code CORD2 based on the second absolute signals of the six systems output from the second magnetoresistance pattern 32. To get. Then, as shown in FIG. 4B, the second absolute value acquisition unit 46 replaces the acquired second irregularly circulating random number code CORD2 with a sequence of integers to acquire the second absolute value ABS2. When the second absolute value acquisition unit 46 acquires the second absolute value ABS2, the second absolute value output unit 38 outputs the second absolute value ABS2. As shown in FIG. 4B, the first absolute value ABS1 from the first absolute value output unit 37 and the second absolute value ABS2 from the second absolute value output unit 38 are a magnetic scale 2 and a magnetic sensor device. When the 3 and the 3 move relative to each other, the output is made when the movement distance of the second pitch P2 is deviated.

The incremental signal acquisition unit 42 acquires a sinusoidal signal based on the signal from the magnetoresistance pattern 34 (+ a) for SIN + signal detection and the signal from the magnetoresistance pattern 34 (−a) for SIN− signal detection. Further, the incremental signal acquisition unit 42 acquires a chord wave signal based on the signal from the magnetoresistance pattern 34 (+ b) for COS + signal detection and the signal from the magnetoresistance pattern 34 (−b) for COS − signal detection. .. Further, the incremental signal acquisition unit 42 performs interpolation division processing based on the sine wave signal and the cosine wave signal, and as shown in FIG. 4C, a periodic incremental signal that changes from zero to a predetermined maximum value. Generate an INC. When the incremental signal INC is generated by the incremental signal acquisition unit 42, the incremental signal output unit 39 outputs the incremental signal INC.

Here, as shown in FIG. 4C, the incremental signal INC is 1 / of the first pitch P1 from the first absolute value output time point At0 at which the first absolute value output unit 37 outputs a new first absolute value ABS1. It is preset to start incrementing from the time when the magnetic scale 2 and the magnetic sensor device 3 move relative to each other by 4 pitches. In this example, in the magnetic scale 2, the incremental patterns 17a and 18a of the incremental track 16 are provided so as to be offset by 1/4 pitch from the first absolute pattern 21a of the first absolute track 21. As a result, the increment start time of the incremental signal INC is set to the time when the magnetic scale 2 and the magnetic sensor device 3 move relative to each other by 1/4 pitch of the first pitch P1 from the first absolute value output time point At0. Further, in this example, the maximum value is 8000, and the incremental signal INC counts from zero to 8000.

The calculation unit 44 calculates the absolute position based on the first absolute value ABS1 and the second absolute value ABS2, and the incremental signal INC. Here, the calculation unit 44 uses the first absolute value ABS1 for calculating the absolute position in the first period T1 from the time when the incremental signal INC becomes 0 to the time when the incremental signal INC reaches the median center of zero and the maximum value. In the second period T2 from when the incremental signal INC reaches the median value to when the incremental signal INC reaches the maximum value, the second absolute value ABS2 is used for calculating the absolute position.

In this example, the maximum value of the incremental signal INC is 8000. Therefore, the median is 4000. Therefore, as shown in FIG. 5, the calculation unit 44 monitors the value of the incremental signal INC when calculating the absolute position (step ST1), and in the first period T1 until the value of the incremental signal INC reaches 0 to 4000. (Step ST1: Yes), the first absolute value ABS1 acquired from the first absolute pattern 21a of the first absolute track 21 is used, and the absolute position is based on the first absolute value ABS1 and the value (phase) of the incremental signal INC. Is calculated (step ST2). On the other hand, in the second period T2 (step ST1: No) from when the value of the incremental signal INC becomes 4000 to when the value of the incremental signal INC reaches 8000 (step ST1: No), the calculation unit 44 uses the second absolute of the second absolute track 22. Using the second absolute value ABS2 acquired from the pattern 22a, the absolute position is calculated based on the second absolute value ABS2 and the value (phase) of the incremental signal INC (step ST3). That is, as shown by an arrow in FIG. 4B, the calculation unit 44 alternately switches between the first absolute value ABS1 and the second absolute value ABS2 at the second pitch P2 when calculating the absolute position.

Here, in the absolute patterns 21a and 22a of the first absolute track 21 and the second absolute track 22, the boundary B of each pattern region existing for each first pitch P1 (see FIGS. 4A and 4B). Then, the magnetic field is unstable. Therefore, when the calculation unit 44 calculates the absolute position, if the absolute value obtained by detecting the boundary B of each pattern region by the magnetoresistive element is used as the absolute value, the absolute value is not accurate and is absolute. In some cases, the position cannot be calculated accurately.

In response to such a problem, in this example, in the absolute track 15, the first absolute pattern 21a of the first absolute track 21 for acquiring the first absolute value ABS1 and the second absolute value ABS2 for acquiring the first absolute value ABS2 are obtained. The second absolute pattern 22a of the second absolute track 22 is deviated by a half pitch (second pitch P2) in the X direction between the magnetic scale 2 and the magnetic sensor device 3. Further, the incremental signal INC is a magnetic scale 2 and a magnetic sensor device for only 1/4 pitch of the first pitch P1 from the first absolute value output time point At0 where the first absolute value output unit 37 outputs a new first absolute value ABS1. The increment starts from the time when 3 and the relative move. Then, in the calculation of the absolute position, the calculation unit 44 receives the first absolute from the first absolute pattern 21a of the first absolute track 21 in the first period T1 from 0 to 4000 when the value of the incremental signal INC reaches. Using the value ABS1, the absolute position is calculated based on the first absolute value ABS1 and the value (phase) of the incremental signal INC. On the other hand, in the second period T2 from when the value of the incremental signal INC becomes 4000 to when the value of the incremental signal INC reaches 8000, the calculation unit 44 is acquired from the second absolute pattern 22a of the second absolute track 22. The second absolute value ABS2 is used.

Therefore, as shown in FIGS. 4 (b) and 4 (c), the calculation unit 44 exists for each first pitch P1 in the first absolute pattern 21a of the first absolute track 21 when calculating the absolute position. The first absolute value ABS1 obtained by detecting the boundary B of each pattern region is not used. Similarly, when calculating the absolute position, the calculation unit 44 is acquired by detecting the boundary B of each pattern region existing for each first pitch P1 in the second absolute pattern 22a of the second absolute track 22. The second absolute value ABS2 is not used either. Therefore, the calculation unit 44 uses an accurate absolute value (first absolute value ABS1 or second absolute value ABS2) regardless of the order of arrangement of the magnetized region and the non-magnetized region in each of the absolute patterns 21a and 22a. The absolute position can be calculated. Therefore, the calculation unit 44 can reliably calculate the absolute position.

(Action effect)
In this example, when calculating the absolute position, the absolute value at the time when the boundary B of each pattern region of the first absolute pattern 21a of the first absolute track 21 is detected is not adopted. Further, when calculating the absolute position, the absolute value at the time when the boundary B of each pattern region of the second absolute pattern 22a of the second absolute track 22 is detected is not adopted. Therefore, the absolute value (first absolute value ABS1 or second absolute value ABS2) is accurate, and the calculated absolute position is accurate.

Further, in this example, the first and second incremental tracks 17 and 18 include incremental patterns 17a and 18a in which the N pole and the S pole are alternately magnetized at the second pitch P2 in the X direction, respectively. Therefore, it is easy to match the cycle of newly acquiring the absolute value with the cycle of the incremental signal INC.

(Modification example)
In the above example, the arithmetic processing unit 40 of the magnetic sensor device 3 may be provided with an incremental signal correction unit that corrects the incremental signal INC. The incremental signal correction unit 43 starts the reference increment by setting the time when the magnetic scale 2 and the magnetic sensor device 3 move relative to each other by 1/4 pitch from the first absolute value output time point At0 to the first pitch P1 as the reference increment start time point I0. When the increment start time It0 of the actual incremental signal INC is deviated from the time point I0, the incremental signal INC is corrected.

FIG. 6 is a block diagram of a control system of a modified magnetic encoder device including an incremental signal correction unit. FIG. 7 is an explanatory diagram of each signal and value acquired by the magnetic sensor device 3 by reading the magnetic scale 2 in the magnetic encoder device of this example. FIG. 7A is an explanatory diagram of an M-sequence irregularly circulating random number code acquired by the first absolute value acquisition unit 45 and the second absolute value acquisition unit 46. FIG. 7B is an explanatory diagram of the absolute value output by the first absolute value output unit 37 and the second absolute value output unit 38 based on the irregularly circulating random number code of the M sequence. FIG. 7C is an explanatory diagram of an incremental signal actually output by the incremental signal output unit 39. FIG. 7D is an explanatory diagram of the correction incremental signal generated by the incremental signal correction unit. FIG. 7 is a flowchart of the absolute position calculation operation. The magnetic encoder device 1A of this example is different from the magnetic encoder device 1 in the configuration and processing of the arithmetic processing unit 40, but the other configurations are the same as those of the magnetic encoder device 1. Therefore, the description of the corresponding configuration will be omitted.

First, the phenomenon that the incremental signal INC actually output from the incremental signal output unit 39 deviates from the preset reference increment start time point I0 is that the installation posture of the magnetic sensor device 3 is the relative movement direction of the magnetic scale 2. It occurs when it is tilted with respect to the X direction. That is, the magnetic encoder device 1 includes an absolute track 15 arranged in the Y direction and extending in the X direction and an incremental track 16 on the magnetic scale 2. On the other hand, the magnetic sensor device 3 includes a magnetic sensing element 12 for acquiring an absolute signal and a magnetic sensing element 13 for acquiring an incremental signal arranged in the Y direction. Therefore, when the installation posture of the magnetic sensor device 3 is tilted in the relative movement direction of the magnetic scale 2 from the reference posture, the magnetic resistance pattern (first magnetic resistance pattern 31 and second magnetic resistance pattern 31) of the magnetic sensing element 12 for acquiring the absolute signal is obtained. Magnetic resistance pattern 32) and magnetic resistance pattern of magnetically sensitive element 13 for incremental signal acquisition (SIN + magnetic resistance pattern 34 (+ a) for signal detection, COS + magnetic resistance pattern 34 (+ b) for signal detection, SIN- signal The arrangement of the magnetic resistance pattern 34 (-a) for detection and the magnetic resistance pattern 34 (-b) for COS-signal detection is displaced in the X direction. As a result, the increment start time It0 of the actual incremental signal INC deviates from the reference increment start time I0.

Here, if the increment start time It0 of the actual incremental signal INC deviates from the reference increment start time I0, there is a problem that the absolute position calculated by the calculation unit 44 becomes an erroneous value. In order to deal with such a problem, the incremental signal correction unit 43 generates a correction incremental signal C_INC that corrects the phase shift of the incremental signal INC.

As shown in FIG. 6, the incremental signal correction unit 43 is provided between the incremental signal output unit 39 and the calculation unit 44. A first absolute value output unit 37, a second absolute value output unit 38, and an incremental signal output unit 39 are connected to the input side of the incremental signal correction unit 43. A calculation unit 44 is connected to the output side of the incremental signal correction unit 43.

As shown in FIG. 8, the incremental signal correction unit 43 first acquires a deviation amount E in which the increment start time It0 of the actual incremental signal INC is deviated from the reference increment start time I0 (step ST11). In other words, in the incremental signal correction unit 43, the increment start time It0 of the actual incremental signal INC is the magnetic scale 2 and the magnetic sensor device 3 by 1/4 pitch from the first absolute value output time point At0 to the first pitch P1. Acquires the phase shift amount E deviated from the time point at which the relative movement is performed (reference increment start time point I0).

Next, the incremental signal correction unit 43 generates a corrected incremental signal C_INC that corrects the phase shift of the incremental signal INC based on the acquired deviation amount E (step ST12). The incremental start time point in the correction incremental signal C_INC coincides with the reference increment start time point I0.

Here, when the correction incremental signal C_INC is generated, the calculation unit 44 calculates the absolute position using the correction incremental signal C_INC (step ST13).

More specifically, as shown in FIG. 7 (c), the incremental signal correction unit 43 has a first time point t0 in which the first absolute value ABS1 and the second absolute value ABS2 change from the same value to different values. The first value INC1 of the incremental signal INC and the second value INC2 of the incremental signal INC of the second time point t2 where the first absolute value ABS1 and the second absolute value ABS2 return to the same value after the first time point t0. Based on this, the deviation amount E is acquired.

That is, the increment start time It0 coincides with the reference increment start time I0 (when the magnetic scale 2 and the magnetic sensor device 3 move relative to each other by 1/4 pitch of the first pitch P1 from the first absolute value output time At0). If so, the time points when the first absolute value ABS1 is newly acquired are the first time point t0 in which the first absolute value ABS1 and the second absolute value ABS2 change from the same value to different values, and the first time point t0. After the time point t0, the first absolute value ABS1 and the second absolute value ABS2 return to the same value, which is the central time point with the second time point t2. Therefore, the difference (distance D1) between the first value INC1 and the maximum value of the incremental signal INC of the first time point t0 in which the first absolute value ABS1 and the second absolute value ABS2 change from the same value to different values, and the first value. The first absolute value ABS1 and the second absolute value ABS2 return to the same value after the first time point t0. The second value INC2 of the incremental signal INC of the second time point t2 (distance D2 from zero to the second value INC2). Is consistent with.

On the other hand, as shown in FIGS. 7 (b) and 7 (c), the increment start time It0 is a magnetic scale of the reference increment start time I0 (1/4 pitch from the first absolute value output time At0 to the first pitch P1). When the distance between 2 and the magnetic sensor device 3 is deviated from the relative movement), the incremental signal at the first time point t0 in which the first absolute value ABS1 and the second absolute value ABS2 change from the same value to different values. The difference (distance D1) between the first value INC1 and the maximum value of INC, and the incremental signal at the second time point t2 where the first absolute value ABS1 and the second absolute value ABS2 return to the same value after the first time point t0. The value is different from the second value INC2 (distance D2) of INC. Further, the difference between the difference (distance D1) between the first value INC1 and the maximum value of the incremental signal INC and the second value INC2 (distance D2 from zero to the second value INC2) is the time when the first absolute value is output. It corresponds to the amount of deviation E between At0 and the phase of the incremental signal INC.

Therefore, as shown by the arrow in FIG. 7D, the incremental signal correction unit 43 generates the correction incremental signal C_INC in which the phase of the incremental signal INC is shifted by the amount corresponding to the deviation amount E. As a result, the incremental start time point in the correction incremental signal C_INC coincides with the reference increment start time point I0. The incremental signal INC and the correction incremental signal C_INC both count from zero to the maximum value (8000) only in phase shift.

If the increment start time It0 does not deviate from the reference increment start time I0, the deviation amount E is zero. Therefore, the incremental signal correction unit 43 sets the incremental signal INC as the correction incremental signal C_INC as it is without shifting the phase of the incremental signal INC.

Here, the acquisition of the deviation amount E by the incremental signal correction unit 43 is performed at the time of installing the magnetic encoder device 1 in which the magnetic sensor device 3 is arranged on the side of the fixed body and the magnetic scale 2 is arranged on the side of the moving body. .. That is, when the moving body is moved with respect to the fixed body to move the magnetic scale 2 and the magnetic sensor device 3 relative to each other at the time of installation, the incremental signal correction unit 43 has the first value of the incremental signal INC at the first time point t0. The difference (distance D1) between INC1 and the maximum value and the second value INC2 (distance D2 from zero to the second value INC2) of the incremental signal INC at the second time point t2 are acquired to calculate the deviation amount E. do. After that, the incremental signal correction unit 43 generates the correction incremental signal C_INC based on the deviation amount E acquired at the time of installation.

Next, in step ST13 of FIG. 8 for calculating the absolute position, the calculation unit 44 monitors the value of the correction incremental signal C_INC (step ST21), and the correction incremental signal C_INC becomes 0 from the time when the correction incremental signal C_INC becomes 0. In the first period T1 (step ST21: Yes), which reaches the median value (4000) between zero and the maximum value, the absolute position is calculated based on the first absolute value ABS1 and the correction incremental signal C_INC (step ST22). On the other hand, in the second period T2 (step ST21: No) where the corrected incremental signal C_INC reaches the maximum value (8000) from the time when the corrected incremental signal C_INC reaches the median value, the calculation unit 44 corrects the corrected incremental value ABS2. The absolute position is calculated based on the incremental signal C_INC (step ST22). That is, as shown by an arrow in FIG. 7B, the calculation unit 44 alternately moves the first absolute value ABS1 and the second absolute value ABS2 every time the second pitch P2 is moved in calculating the absolute position. Switch and use.

According to this example, the increment start time It0 of the incremental signal INC is set in advance due to the fact that the installation posture of the magnetic sensor device 3 is tilted with respect to the relative movement direction (X direction) of the magnetic scale 2. When the deviation is made with respect to the reference increment start time point I0, the corrected incremental signal C_INC is generated by correcting the phase shift of the incremental signal INC based on the deviation amount E. Further, the correction incremental signal C_INC is used to calculate the absolute position. Therefore, the absolute position calculated by the calculation unit 44 is a correct value.

Further, also in this example, when calculating the absolute position, the absolute value at the time when the boundary B of each pattern region of the first absolute pattern 21a of the first absolute track 21 is detected is not adopted. Further, when calculating the absolute position, the absolute value at the time when the boundary B of each pattern region of the second absolute pattern 22a of the second absolute track 22 is detected is not adopted. Therefore, the absolute value (first absolute value ABS1 or second absolute value ABS2) used for calculating the absolute value is accurate, and the calculated absolute position is accurate.

Further, in the magnetic encoder device 1A of this example, the incremental signal INC increment start time point due to the fact that the installation posture of the magnetic sensor device 3 is tilted with respect to the relative movement direction (X direction) of the magnetic scale 2. When It0 deviates from the preset reference increment start time point I0, a correction incremental signal C_INC that corrects the phase shift of the incremental signal INC is generated based on the deviation amount E, and the correction incremental signal C_INC is generated. The absolute position is calculated using. Therefore, when installing the magnetic encoder device 1A, it is not necessary to strictly define the positional relationship between the magnetic scale 2 and the magnetic sensor device 3. Therefore, the installation work of the magnetic encoder device 1A is easy.

As shown in FIG. 7 (c), the incremental signal correction unit 43 is the third incremental signal INC of the third time point t3 in which the first absolute value ABS1 and the second absolute value ABS2 change from different values to the same value. The amount of deviation E is based on the trivial INC3 and the fourth value INC4 of the incremental signal INC of the fourth time point t4 in which the first absolute value ABS1 and the second absolute value ABS2 return to different values after the third time point t3. Can also be obtained.

In this case, the difference between the first value INC1 and the median of the incremental signal INC of the first time point t0 in which the first absolute value ABS1 and the second absolute value ABS2 change from different values to the same value (distance D3). And the difference (distance D4) between the second value INC2 and the median of the incremental signal INC of the second time point t2 in which the first absolute value ABS1 and the second absolute value ABS2 return to different values after the first time point t0. The difference between the two corresponds to the deviation amount E between the first absolute value output time point At0 and the phase of the incremental signal INC.

(Other embodiments)
In the magnetic encoder devices 1 and 1A, the incremental signal output unit 39 detects two incremental tracks 17 and 18 and outputs an incremental signal, but outputs an incremental signal from one incremental track. The configuration may be adopted.

Further, in the above examples of the magnetic encoder devices 1 and 1A, the incremental signal output by the incremental signal output unit 39 may be a vernier signal. In this case, two incremental tracks having different pitch incremental patterns are provided on the magnetic scale, and two incremental signals having different wavelengths are transmitted by the magnetic sensing element 13 for acquiring the incremental signal of the magnetic sensor device. get. Then, the incremental signal output unit 39 generates and outputs a vernier signal longer than the period of these incremental signals based on the two acquired incremental signals.

Here, the period of the vernier signal is the period corresponding to the first pitch P of the absolute pattern. Further, the vernier signal includes the magnetic scale 2 and the magnetic sensor device 3 by 1/4 pitch of the first pitch P from the time of the first absolute value output in which the first absolute value output unit 37 outputs a new first absolute value ABS1. It is assumed that the increment starts from the time when the relative movement is performed.

1.1A ... Magnetic encoder device (position detection device), 2 ... Magnetic scale, 3 ... Magnetic sensor device, 5 ... Magnetic track, 7 ... Holder, 8 ... Cable, 9 ... Facing surface, 9a ... Opening, 10 ... Magnetic sensor, 11 ... Sensor board, 12 ... Magnetic element for acquiring absolute signal, 13 ... Magnetic element for acquiring incremental signal, 15 ... Absolute track, 16 ... Incremental track, 17 ... First incremental track, 18 ... No. 2 Incremental track, 17a ... 1st incremental pattern, 18a ... 2nd incremental pattern, 21 ... 1st absolute track, 21a ... 1st absolute pattern, 2
2 ... 2nd absolute track, 22a ... 2nd absolute pattern, 31 ... 1st magnetic resistance pattern, 32 ... 2nd magnetic resistance pattern, 34 ... magnetic resistance pattern, 34 ... magnetic resistance pattern for SIN-signal detection, 34 ... COS + magnetic resistance pattern for signal detection, 34 ... COS-magnetic resistance pattern for signal detection, 34 ... magnetic resistance pattern for SIN + signal detection, 37 ... first absolute value output unit, 38 ... second absolute value output unit, 39 ... Incremental signal output unit, 40 ... Arithmetic processing unit, 41 ... Absolute value acquisition unit, 42 ... Incremental signal acquisition unit, 43 ... Incremental signal correction unit, 44 ... Calculation unit, 45 ... First absolute value acquisition unit, 46 ... 2nd absolute value acquisition unit, ABS1 ... 1st absolute value, ABS2 ... 2nd absolute value, CORD1 ... 1st irregular circulation random number code, CORD2 ... 2nd irregular circulation random number code, INC1 ... 1st value of incremental signal INC , INC2 ... Incremental signal INC 2nd value, INC3 ... Incremental signal INC 3rd value, INC4 ... Incremental signal INC 4th value, P1 ... 1st pitch, P2 ... 2nd pitch, T1 ... 1st period, T2 … Second period

Claims (6)

The absolute track having an absolute pattern in which the magnetized region and the non-magnetized region are arranged at the first pitch, and the absolute track having an incremental pattern in which the magnetized region and the non-magnetized region are alternately arranged. A magnetic scale having an incremental track provided in parallel, an absolute value output unit that reads the absolute track of the magnetic scale that moves relative to each other and outputs an absolute value, and a zero that reads the incremental track of the magnetic scale that moves relative to each other. A position having an incremental signal output unit that outputs a periodic incremental signal that changes from to a predetermined maximum value, and a magnetic sensor device including a calculation unit that calculates an absolute position based on the absolute value and the incremental signal. In the detector
The absolute track has a first track having the absolute pattern and the absolute pattern deviated by a second pitch by half of the first pitch in a relative movement direction with respect to the first track. With a second track installed in parallel,
The absolute value output unit includes a first absolute value output unit that reads the first track and outputs the first absolute value, and a second absolute value output unit that reads the second track and outputs the second absolute value. , Equipped with
The increment start time when the incremental signal starts incrementing is the magnetic scale of 1/4 pitch of the first pitch from the first absolute value output time when the first absolute value output unit outputs a new absolute value. It is set at the time when the magnetic sensor device and the magnetic sensor device move relative to each other.
The calculation unit uses the first absolute value to calculate the absolute position in the first period from the time when the incremental signal becomes 0 to the time when the incremental signal reaches the median of zero and the center of the maximum value. In the second period from the time when the incremental signal reaches the median value to the time when the incremental signal reaches the maximum value, the second absolute value is used for calculating the absolute position.
It has an incremental signal correction unit that corrects the incremental signal.
The incremental signal correction unit starts the reference increment with the time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time when the first absolute value is output as the reference increment start time. The amount of deviation in which the incremental start time point of the actual incremental signal is deviated from the time point is acquired and before.
A corrected incremental signal is generated by correcting the phase shift of the incremental signal based on the amount of deviation.
The calculation unit uses the correction incremental signal to calculate the absolute position, and from the time when the correction incremental signal becomes 0 until the correction incremental signal reaches the median center of zero and the maximum value, the absolute value is reached. The first absolute value is used for calculating the position, and the second absolute value is used for calculating the absolute position from the time when the corrected incremental signal reaches the median until the corrected incremental signal reaches the maximum value. ,
The incremental signal correction unit is a first value of the incremental signal at the first time point in which the first absolute value and the second absolute value are changed from the same value to different values, and next to the first time point. A position detecting device characterized in that the deviation amount is acquired based on the second value of the incremental signal at a second time point in which the first absolute value and the second absolute value return to the same value . The absolute track having an absolute pattern in which the magnetized region and the non-magnetized region are arranged at the first pitch, and the absolute track having an incremental pattern in which the magnetized region and the non-magnetized region are alternately arranged. A magnetic scale having an incremental track provided in parallel, an absolute value output unit that reads the absolute track of the magnetic scale that moves relative to each other and outputs an absolute value, and a zero that reads the incremental track of the magnetic scale that moves relative to each other. A position having an incremental signal output unit that outputs a periodic incremental signal that changes from to a predetermined maximum value, and a magnetic sensor device including a calculation unit that calculates an absolute position based on the absolute value and the incremental signal. In the detector
The absolute track has a first track having the absolute pattern and the absolute pattern deviated by a second pitch by half of the first pitch in a relative movement direction with respect to the first track. With a second track installed in parallel,
The absolute value output unit includes a first absolute value output unit that reads the first track and outputs the first absolute value, and a second absolute value output unit that reads the second track and outputs the second absolute value. , Equipped with
The increment start time when the incremental signal starts incrementing is the magnetic scale of 1/4 pitch of the first pitch from the first absolute value output time when the first absolute value output unit outputs a new absolute value. It is set at the time when the magnetic sensor device and the magnetic sensor device move relative to each other.
The calculation unit uses the first absolute value to calculate the absolute position in the first period from the time when the incremental signal becomes 0 to the time when the incremental signal reaches the median of zero and the center of the maximum value. In the second period from the time when the incremental signal reaches the median value to the time when the incremental signal reaches the maximum value, the second absolute value is used for calculating the absolute position.
It has an incremental signal correction unit that corrects the incremental signal.
The incremental signal correction unit starts the reference increment with the time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time when the first absolute value is output as the reference increment start time. An amount of deviation in which the actual incremental start time of the incremental signal is deviated from the time point is acquired, and a corrected incremental signal is generated by correcting the phase shift of the incremental signal based on the amount of deviation.
The calculation unit uses the correction incremental signal to calculate the absolute position, and from the time when the correction incremental signal becomes 0 until the correction incremental signal reaches the median center of zero and the maximum value, the absolute value is reached. The first absolute value is used to calculate the position, and the correction a is performed from the time when the correction incremental signal reaches the median value.
Until the incremental signal reaches the maximum value, the second absolute value is used to calculate the absolute position.
The incremental signal correction unit is a third value of the incremental signal at a third time point in which the first absolute value and the second absolute value change from different values to the same value, and next to the third time point. A position detecting device characterized in that the deviation amount is acquired based on the fourth value of the incremental signal at a fourth time point in which the first absolute value and the second absolute value return to different values . The position detecting device according to claim 1 or 2 , wherein the incremental track includes an incremental pattern in which N poles and S poles are alternately magnetized at the second pitch in the relative moving direction. The absolute track having an absolute pattern in which the magnetized region and the non-magnetized region are arranged at the first pitch, and the absolute track having an incremental pattern in which the magnetized region and the non-magnetized region are alternately arranged. A magnetic scale having an incremental track provided in parallel, an absolute value output unit that reads the absolute track of the magnetic scale that moves relative to each other and outputs an absolute value, and an incremental track of the magnetic scale that moves relative to each other are read. A magnetic sensor device including an incremental signal output unit that outputs a periodic incremental signal that changes from zero to a predetermined maximum value, and a position detection device that calculates an absolute position based on the absolute value and the incremental signal. In the position detection method of
As the absolute track, the first track having the absolute pattern and the absolute pattern having the second pitch deviated by half of the first pitch in the relative movement direction with respect to the first track are provided in advance. A second track provided in parallel with the track is provided, and as the absolute value output unit, a first absolute value output unit that reads the first track and outputs the first absolute value and the second track are provided. A second absolute value output unit that reads and outputs a second absolute value is provided, and the first absolute value output unit outputs a new absolute value at an increment start time point when the incremental signal starts incrementing. It is set at the time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time when 1 absolute value is output.
In the first period from the time when the incremental signal becomes 0 to the time when the incremental signal reaches the median of zero and the center of the maximum value, the first absolute value is used for calculating the absolute position, and the incremental signal is the incremental signal. In the second period from the time when the median value is reached until the incremental signal reaches the maximum value, the second absolute value is used to calculate the absolute position.
The time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time when the first absolute value is output is set as the reference increment start time, and the actual time with respect to the reference increment start time is described. Obtain the amount of deviation that the incremental start point of the incremental signal is off, and
A corrected incremental signal that corrects the phase shift of the incremental signal based on the shift amount is generated.
The corrected incremental signal is used for calculating the absolute position, and the absolute position is calculated from the time when the corrected incremental signal becomes 0 until the corrected incremental signal reaches the median center of zero and the maximum value. Using the first absolute value, the second absolute value is used to calculate the absolute position from the time when the corrected incremental signal reaches the median until the corrected incremental signal reaches the maximum value.
The first value of the incremental signal at the first time point in which the first absolute value and the second absolute value change from the same value to different values, and the first value next to the first time point.
A position detection method comprising acquiring the deviation amount based on the second value of the incremental signal at a second time point in which the first absolute value and the second absolute value return to the same value . The absolute track having an absolute pattern in which the magnetized region and the non-magnetized region are arranged at the first pitch, and the absolute track having an incremental pattern in which the magnetized region and the non-magnetized region are alternately arranged. A magnetic scale having an incremental track provided in parallel, an absolute value output unit that reads the absolute track of the magnetic scale that moves relative to each other and outputs an absolute value, and an incremental track of the magnetic scale that moves relative to each other are read. A magnetic sensor device including an incremental signal output unit that outputs a periodic incremental signal that changes from zero to a predetermined maximum value, and a position detection device that calculates an absolute position based on the absolute value and the incremental signal. In the position detection method of
As the absolute track, the first track having the absolute pattern and the absolute pattern having the second pitch deviated by half of the first pitch in the relative movement direction with respect to the first track are provided in advance. A second track provided in parallel with the track is provided, and as the absolute value output unit, a first absolute value output unit that reads the first track and outputs the first absolute value and the second track are provided. A second absolute value output unit that reads and outputs a second absolute value is provided, and the first absolute value output unit outputs a new absolute value at an increment start time point when the incremental signal starts incrementing. It is set at the time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time when 1 absolute value is output.
In the first period from the time when the incremental signal becomes 0 to the time when the incremental signal reaches the median of zero and the center of the maximum value, the first absolute value is used for calculating the absolute position, and the incremental signal is the incremental signal. In the second period from the time when the median value is reached until the incremental signal reaches the maximum value, the second absolute value is used to calculate the absolute position.
The time when the magnetic scale and the magnetic sensor device move relative to each other by 1/4 pitch of the first pitch from the time when the first absolute value is output is set as the reference increment start time, and the actual time with respect to the reference increment start time is described. Obtain the amount of deviation that the incremental start point of the incremental signal is off, and
A corrected incremental signal that corrects the phase shift of the incremental signal based on the shift amount is generated.
The corrected incremental signal is used for calculating the absolute position, and the absolute position is calculated from the time when the corrected incremental signal becomes 0 until the corrected incremental signal reaches the median center of zero and the maximum value. Using the first absolute value, the second absolute value is used to calculate the absolute position from the time when the corrected incremental signal reaches the median until the corrected incremental signal reaches the maximum value .
The third value of the incremental signal at the third time point in which the first absolute value and the second absolute value change from different values to the same value, and the first absolute value and the above after the third time point. A position detection method comprising acquiring the deviation amount based on the fourth value of the incremental signal at the fourth time point in which the value returns to a value different from the second absolute value. The position detection method according to claim 4 or 5 , wherein the incremental track is provided with an incremental pattern in which N poles and S poles are alternately magnetized at the second pitch in the relative moving direction.

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