JP2000055606A - Position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position detector capable of maintaining high absolute precision with inexpensive detector constitution, and excellent in operatability in the construction of the detector. SOLUTION: In this position transducer, a primary side (rotor 111) of a magnetic detecting part 101 is excited by a drive part 122 in an operation part 102, an output voltage of a secondary part (stators 112, 113) of the detecting part 101 is converted into a digital value by an A/D converter 123 therein, a positional data is calculated based on a converted result therein in a CPU 121, and then the positional data is corrected therein in reference to a position correcting data stored in an EEPROM 124 to be transmitted to the outside with a prescribed period as a position-detected result via serial interface 125.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device for detecting the position of an electric motor or the like by using the output of a magnetic position detecting means such as a resolver. The present invention relates to a position detecting device which maintains and is excellent in operability in terms of construction of the detecting device.

[0002]

2. Description of the Related Art Hitherto, various position detecting devices for detecting position information using the output of a magnetic position detecting means such as a resolver have been proposed. This resolver is of a rotary type or a linear type. For example, the rotary resolver is also called a two-phase synchro, and is a control transformer having two-phase windings orthogonal to each other on a stator. When the rotor winding is excited by an AC voltage, the stator winding is proportional to the sine (sin θ) and cosine (cos θ) of the position θ, respectively. Voltage. Since the voltage applied to the rotor winding is used as the amplitude and the two-dimensional vector having the angle θ given to the axis can be decomposed into two orthogonal components, the resolver is called a resolver. Using the output of a magnetic position detecting means such as a resolver,
As a position detecting device for detecting a rotation angle or the like in an electric motor or the like, a "amplitude servo type (tracking type)" in which a resolver is excited in one phase to take in a secondary-side two-phase voltage, or a secondary in which a resolver is excited in two phases. "Phase servo type" that takes in the voltage on the side
There is a detection device. Regardless of the type of detection device used, an R / D converter (resolver-to-digital converter) or the like is used to convert the resolver signal into a digital signal by converting it into a pulse train or parallel read data. Was getting.

[0003]

However, in such a conventional position detecting device, since the output of the resolver is directly digitized, the accuracy of the detecting device depends entirely on the accuracy of the resolver. There was a problem. Further, since the R / D converter used in the conventional position detecting device is expensive, there is also a problem in device cost.
Further, with respect to a cable for taking in a signal from a resolver, there is a problem that if the cable length changes, the system needs to be readjusted. The present invention has been made in view of the above-described conventional circumstances and problems, and has a lower cost in a position detecting device that detects the position of an electric motor or the like using the output of a magnetic position detecting means such as a resolver. It is an object of the present invention to provide a position detecting device which maintains a high absolute accuracy in the device configuration and is excellent in operability in terms of construction of the detecting device.

[0004]

According to a first aspect of the present invention, there is provided a position detecting apparatus comprising a magnetic position detecting means, wherein the magnetic position detecting means comprises: Drive means for exciting the primary side, conversion means for converting the secondary output voltage of the magnetic position detection means into a digital value, position information is calculated based on the conversion result of the conversion means, and stored in the storage means The arithmetic unit includes a calculating unit that corrects the position information with reference to the stored position correction data, and a serial interface that transmits the corrected position information at a predetermined cycle.
A position detecting device according to a second aspect of the present invention is the position detecting device according to the first aspect, wherein the magnetic position detecting means and the arithmetic means are always integrally connected, and the position correction data held in the storage means is provided. Is data unique to the magnetic position detecting means. Further, in the position detecting device according to claim 3, in the position detecting device according to claim 1 or 2, the magnetic position detecting means and the arithmetic means are always integrally connected via a signal transmission means of a fixed length. The arithmetic means can be installed in a favorable environment.

In the position detecting device according to the first aspect of the present invention, in the calculating means, the primary side of the magnetic position detecting means is excited by the driving means, and the output voltage on the secondary side of the magnetic position detecting means is converted. The calculation means calculates the position information based on the conversion result of the conversion means, and then corrects the position information with reference to the position correction data held in the storage means. The position detection result is transmitted to the outside via the serial interface at a predetermined cycle. Therefore, in a position detecting device that detects the position of an electric motor or the like using the output of a magnetic position detecting means such as a resolver, the position can be captured as a digital value without using an expensive R / D converter or the like as in the related art. Therefore, it is possible to reduce the cost of the apparatus, and to use a magnetic type position detecting means having repetition accuracy and to correct the position information which is a calculation result. A detection device can be realized. Furthermore, if the data is transmitted to the external device (a higher-level controller or the like as a control system) at a predetermined cycle via the serial interface, the processing by the arithmetic means can be performed during the sampling time in the sampling control performed by the external device. The real-time property required in the pulse dispensing process of the conventional R / D converter is unnecessary. In the position detecting device according to the second aspect, the magnetic position detecting means and the arithmetic means are always integrally connected, and the position correction data held in the storage means is data unique to the magnetic position detecting means. desirable. Further, in the position detecting device according to the third aspect, the magnetic position detecting means and the calculating means are always integrally connected via a fixed length signal transmitting means, and the calculating means can be installed in a favorable environment. It is desirable. This eliminates the need for conventional system readjustment each time the cable length changes. In addition, the correction process based on the data unique to the magnetic position detection means requires that the magnetic position detection means have repetition accuracy, so that absolute accuracy is not required. As a result, excellent operability can be realized in terms of construction of the position detection device.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a position detecting device according to the present invention will be described below in detail with reference to the drawings in the order of [first embodiment] and [second embodiment]. [First Embodiment] FIG. 1 is a block diagram of a position detecting device according to a first embodiment of the present invention. In the figure, a position detecting device according to the present embodiment includes a rotating rotor (primary side) 11.
A magnetic detection unit (magnetic position detection unit) 101 using a rotary resolver including a 1 and two-phase stators (secondary sides) 112 and 113; and a calculation unit (calculation unit) 102 It is configured. The position detecting device of the present embodiment is an “amplitude servo type (tracking type) position detecting device that excites the rotor 111 of the magnetic detection unit 101 by one phase and takes in the two-phase voltages of the secondary sides (stators) 112 and 113. It is. The calculation unit 102 includes a drive unit (drive unit) 122 that outputs an excitation signal DRV for exciting the rotor 111 of the magnetic detection unit 101 based on a control signal from the CPU 121, and outputs 151 and 151 of the stators 112 and 113 of the magnetic detection unit 101.
A / D converter (conversion means) 123 for converting each of these 152 into digital values, EEPROM (storage means; electrically rewritable nonvolatile memory) 124 for holding position correction data, and conversion results of A / D converter 123 CPU (calculating means) 121 that calculates position information based on the position information and corrects the position information with reference to position correction data held in the EEPROM 124, and uses the corrected position information as a detection result of the position detection device. A serial interface (SIU) 125 for transmitting data at a predetermined cycle. Here, the position correction data held in the EEPROM 124 is, for example, connected to another position detecting device having high measurement accuracy and the position detecting device to a personal computer or the like in an adjustment stage when the position detecting device is configured. Then, an error of the position detecting device is measured by comparing the position information detected by the two, and the error data is written to the EEPROM 124 from the personal computer via the serial interface 125 as the position correction data. Therefore, the position correction data is data unique to the position detection device (magnetic detection unit 101), and is already held when the position detection device is operated. As described above, by performing the correction process using the data unique to the magnetic detection unit 101, it is sufficient that the magnetic detection unit 101 has the repetition accuracy, and the absolute accuracy is not required. The CPU 121, the A / D converter 123, the EEPROM 124, and the serial interface 125 in the arithmetic unit 102 are connected to each other via a bus (BUS) 150. Here, the bus 150 is a system bus including a data bus, an address bus, and other control signals. Also, from the serial interface 125,
Via the transmission path 105, the corrected position information is transmitted as serial data of a predetermined cycle to an external device (such as a higher-order servo or controller in the control system).

Next, the operation of the position detecting device of this embodiment will be described with reference to the voltage waveform chart of each signal shown in FIG. First, when the CPU 121 outputs an excitation pulse (see FIG. 2A) based on the excitation signal DRV to the magnetic detection unit 101 via the drive unit 122 to excite the rotor 111, the stators 112 and 113 detect detection pulses, respectively. The unit outputs 151 and 152 are output to the A / D converter 123. That is, the magnetism detection unit 101 is a multiplication type pulse transformer, and the detection unit outputs 151 and 152 output the excitation signal DRV as shown in FIGS. 2B and 2C, respectively.
Rotation angle θ with respect to the peak value Er of the (excitation pulse)
Are obtained by multiplying the sine value (sin θ) and the cosine value (cos θ) by the peak values Es and Ec. These detection unit outputs 151 and 152 are converted into digital values in the A / D converter 123 and are sent to the CPU 1 via the bus 150.
21. In the CPU 121, the peak values Es, E
c (Es / Ec), that is, (si
nθ / cos θ = tan θ), and further, arctan θ is obtained by referring to a function table or the like to obtain position information. Further, the position information is subjected to error correction with reference to the position correction data held in the EEPROM 124. The position information finally obtained by the error correction is transmitted to an external device (such as a higher-order servo or controller in the control system) as serial data of a predetermined cycle via the serial interface 125 and the transmission path 105.

As described above, in the position detecting device of the present embodiment, the position detecting device for detecting the position of the electric motor or the like using the output of the magnetic position detecting unit 101 such as a resolver is expensive as in the prior art. Since digital values can be captured by the A / D converter 123 without using an R / D converter or the like, an inexpensive R / S converter (resolver-serial converter) can be realized, and a lower-cost device configuration It can be. In addition, since the magnetic detection unit 101 having the repetition accuracy is used, and the CPU 121 refers to the position correction data held in the EEPROM 124 to correct the position information, an error is detected. The device can be realized. Further, since the data is transmitted to the external device (a higher-order servo or controller as a control system) at a predetermined cycle via the serial interface 125, the arithmetic unit 102 (CPU 121) performs the sampling time in the sampling control performed by the external device. The processing may be performed, and the real-time property (processing performance of about several microseconds) required in the pulse delivery processing of the conventional R / D converter is unnecessary. For example, if the interval of the sampling control performed by the host controller is about 125 μsec, the arithmetic unit 1
It is sufficient for the 02 (CPU 121) to perform processing within this time or less.

Next, the position detecting device of the present embodiment is shown in FIG.
Is realized by the external configuration as shown in FIG. That is, the magnetic detection unit 101 and the arithmetic unit 102 are always integrally connected via a cable (signal transmission means) 103 having a fixed length of about 1 m.
A cable or the like forming the transmission path 105 is connected to the connector 126 coupled to the connector 25, and transmits the position information of the detection result to an external device (upper controller or the like). Also, without using an optical encoder, a magnetic detection unit (resolver) 1
01 is selected and used by the magnetic detection unit (resolver) 1
01 is a detection means for robust environment resistance such as heat resistance, vibration resistance, impact resistance, and the like. On the other hand, since the optical encoder has an optical disk and electronic components therein, the environment resistance is improved. Due to not having. That is, since the magnetism detecting unit (resolver) 101 has substantially the same manufacturing method as that of the motor and thus has excellent environmental resistance, it can be installed in the motor and used even in a high temperature or a place with a lot of vibration. However, since the arithmetic unit 102 is configured by an electronic circuit, if it is installed at the rear end of the motor or the like, the arithmetic unit 102 will be broken due to heat generation of the motor. Further, when the wiring length of the cable 103 changes, the magnetic detection unit (resolver) 101 needs to be readjusted each time. Therefore, in the present embodiment, the magnetic detection unit 101 and the calculation unit 102 are always integrally connected by a fixed-length cable 103, and the calculation unit 102 is installed in a favorable environment. This eliminates the need for readjustment of the device each time the cable length changes, thereby achieving excellent operability in terms of constructing the position detection device.

[Second Embodiment] FIG. 4 is a block diagram of a position detecting device according to a second embodiment of the present invention. In the figure, a position detecting device of the present embodiment includes a rotating rotor (secondary side) 211 and a two-phase stator (primary side) 21.
2 and 213, a magnetic detection unit (magnetic position detection unit) 201 using a rotary resolver and a calculation unit (calculation unit) 202. The position detection device of the present embodiment includes a stator 212 of the magnetic detection unit 201,
This is a “phase servo type” position detection device that excites the two-phase voltage of the secondary side (rotor) 211 by exciting the two-phase 213.
The arithmetic unit 202 includes drive units (drive units) 222C and 222S that output excitation signals DRVC and DRVS for exciting the stators 212 and 213 of the magnetic detection unit 201 based on a control signal from the CPU 221; A / D converter (conversion means) 223 for converting the output 251 into a digital value, an EEPROM (storage means; electrically rewritable nonvolatile memory) 224 for holding position correction data, and conversion of the A / D converter 223 A CPU (calculating means) 221 for calculating position information based on the result and referring to position correction data held in the EEPROM 224 to correct the position information; And a serial interface (SIU) 225 for transmitting at a predetermined period. Here, similarly to the first embodiment, the position correction data held in the EEPROM 224 is data unique to the position detection device (magnetic detection unit 101) in which error data measured in advance is written as position correction data. Yes, they are already stored when the position detecting device is operated. Further, the CPUs 221 and A in the arithmetic unit 202
The / D converter 223, the EEPROM 224, and the serial interface 225 are also connected to each other via a bus (BUS) 250 as in the first embodiment.
Also, from the serial interface 225, the transmission path 2
The corrected position information is transmitted to an external device (such as a higher-order servo or controller in the control system) as serial data of a predetermined cycle via the control unit 05. As described above, the position detection device of the present embodiment is an application of the present invention to a “phase servo type”. Although the specific configuration is different from the first embodiment in which the present invention is applied to the "amplitude servo type (tracking type)", the operation can be easily analogized from the first embodiment. The detailed description of the operation is omitted. As a matter of course, the same effects as those of the first embodiment can be obtained. Further, in the first and second embodiments, a rotary resolver has been described as the magnetic detection unit (magnetic position detecting means). However, even if a linear resolver is used, the same effects as those of the embodiments can be obtained. be able to.

[0011]

As described above, according to the position detecting device of the present invention, in the calculating means, the primary side of the magnetic position detecting means is excited by the driving means, and the secondary side of the magnetic position detecting means is excited. The output voltage is converted to a digital value by the conversion means, and the calculation means calculates the position information based on the conversion result of the conversion means, and then refers to the position correction data held in the storage means to calculate the position information. Since the correction is performed and transmitted as a position detection result to the outside at a predetermined cycle via the serial interface, the apparatus can be configured at a lower cost. Since the resulting position information is corrected, a digitized position detecting device that maintains high absolute accuracy can be realized. If to transmit to the external device (host controller or the like) at a predetermined period Te may real time by performing the processing by the arithmetic unit during the sampling period in the sampling control performed by the external device is not required. Further, according to the position detecting device of the present invention, the magnetic position detecting means and the arithmetic means are always integrally connected via a fixed length signal transmitting means, and the position correction data held in the storage means is a magnetic position detecting means. Since the data is unique to the means and the calculation means can be installed in a favorable environment, system readjustment is not required.Also, it is sufficient if the magnetic position detection means has repetition accuracy by correction processing. Accuracy becomes unnecessary, and as a result, excellent operability can be realized in terms of construction of the position detection device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a position detection device according to a first embodiment of the present invention.

FIG. 2 is a voltage waveform diagram of each signal for explaining an operation of the position detection device of the first embodiment.

FIG. 3 is an external configuration diagram of the position detection device according to the first embodiment.

FIG. 4 is a configuration diagram of a position detection device according to a second embodiment of the present invention.

[Explanation of symbols]

 101, 201 Magnetic detection unit (magnetic position detection unit) 102, 202 Operation unit (operation unit) 102 103 Cable (signal transmission unit) 105, 205 Transmission line 111, 211 Rotor 112, 113 Stator 121, 221 CPU (calculation unit) 122, 222C, 222S Driving unit (driving means) 123.223 A / D converter (conversion means) 124, 224 EEPROM (storage means) 125, 225 Serial interface (SIU) 126 Connector DRV, DRVC, DRVS excitation signal 150, 250 bus (BUS) 151, 152, 251 Detector output

Claims (3)

[Claims] 1. A position detecting device comprising magnetic position detecting means, wherein: a driving means for exciting a primary side of the magnetic position detecting means; and a digital output value of a secondary side output voltage of the magnetic position detecting means. Conversion means for calculating the position information based on the conversion result of the conversion means, and calculating means for correcting the position information by referring to the position correction data held in the storage means, A position detecting device, comprising: a calculating means having a serial interface for transmitting position information at a predetermined cycle. 2. The method according to claim 1, wherein the magnetic position detecting means and the calculating means are always integrally connected, and the position correction data held in the storage means is data unique to the magnetic position detecting means. The position detecting device according to claim 1. 3. The magnetic position detecting means and the calculating means are always integrally coupled via a fixed length signal transmitting means.
The position detecting device according to claim 1, wherein the calculation unit can be installed in a favorable environment.