JP2004194490A - Brushless motor controlling method - Google Patents

Brushless motor controlling method Download PDF

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Publication number
JP2004194490A
JP2004194490A JP2002363042A JP2002363042A JP2004194490A JP 2004194490 A JP2004194490 A JP 2004194490A JP 2002363042 A JP2002363042 A JP 2002363042A JP 2002363042 A JP2002363042 A JP 2002363042A JP 2004194490 A JP2004194490 A JP 2004194490A
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JP
Japan
Prior art keywords
sensor
rotor
phase
brushless motor
motor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2002363042A
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Japanese (ja)
Inventor
Yoichi Shindo
Kazuhiko Tachikawa
洋一 新藤
和彦 立川
Original Assignee
Mitsuba Corp
株式会社ミツバ
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Application filed by Mitsuba Corp, 株式会社ミツバ filed Critical Mitsuba Corp
Priority to JP2002363042A priority Critical patent/JP2004194490A/en
Publication of JP2004194490A publication Critical patent/JP2004194490A/en
Pending legal-status Critical Current

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Abstract

<P>PROBLEM TO BE SOLVED: To improve the reliability of a brushless motor, by providing redundancy to a failure of a rotor position detecting device. <P>SOLUTION: A first sensor group H1, that comprises a plurality of Hall sensors 10 (H1a, H1b, H1c) and detects a rotor rotational position by detecting the magnetism of a rotor magnet, and a second sensor group H2, that comprises a plurality of Hall sensors (H2a, H2b, H2c) arranged at an interval by a deflection angle X to each of the Hall sensors H1a, H1b, H1c are provided. When the Hall sensor H1a operates normally, an overlapped conducting control is performed with both sensor groups H1, H2. If any one of the Hall sensors fails, a square-wave control is performed using the sensor group that does not include the failed sensor. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control method of a brushless motor, and more particularly to a technique effective when applied to a brushless motor used in an electric power steering device and an electronically controlled throttle valve device.
[0002]
[Prior art]
In recent years, as the reliability of control circuits has been improved, brushless motors having good maintainability have been increasingly used as drive sources for electric power steering devices, electronically controlled throttle valve devices for engines, and the like. Generally, in a brushless motor, the rotation position of a rotor having a magnet is detected by a magnetic detection element such as a Hall IC, and based on the detection result, the armature coils on the stator side are sequentially excited to rotate the rotor. Further, there is a motor in which the rotor rotational position is precisely detected by using a resolver, an encoder, or the like, and a torque ripple is reduced by performing sine wave driving or the like.
[0003]
[Problems to be solved by the invention]
However, in such a brushless motor, a failure of the rotor position detecting device causes a serious obstacle. For example, in a three-phase brushless motor, if only one of the three magnetic detection elements fails, the rotor cannot be rotated. This is the same when a resolver or an encoder is used. Such a failure of the rotor position detecting device causes a malfunction in an electric power steering device, an electronically controlled throttle valve device, and the like, and an improvement thereof has been demanded.
[0004]
SUMMARY OF THE INVENTION It is an object of the present invention to provide redundancy for a failure of a rotor position detecting device and improve the reliability of a brushless motor.
[0005]
[Means for Solving the Problems]
A brushless motor control method according to the present invention is directed to controlling a brushless motor including a stator having a multi-phase armature coil and a rotor having a permanent magnet and rotatably disposed inside or outside the stator. A first sensor group comprising a plurality of magnetic detection elements arranged on the stator side, the first sensor group detecting a magnetism of the permanent magnet to detect a rotational position of the rotor, and the first sensor group. And a second sensor group comprising a plurality of magnetic detecting elements and a plurality of magnetic detecting elements arranged at predetermined intervals, and detecting a magnetism of the permanent magnet to detect a rotational position of the rotor. When the magnetic detection elements of the first and second sensor groups fail, the use of the sensor group including the failed magnetic detection element is stopped, and the sensor including no failed magnetic detection element is stopped. Based on the rotation position detection result of the rotor by sub group, and performing energization control of the armature coil.
[0006]
According to the present invention, when the Hall sensor fails, rectangular wave control is performed using the sensor group that does not include the failure sensor. As long as it belongs, the motor is driven by the other remaining normal sensors and the motor function is maintained. For this reason, by using the motor of the present invention, in an electric power steering device, an electronically controlled throttle valve device, or the like, redundancy can be provided for a sensor abnormality, and product reliability is improved.
[0007]
In the brushless motor control method, when the magnetic detection element fails, the energization of the armature coil may be advanced or retarded. Further, in the brushless motor control method, when the magnetic detection element is normal, based on the rotational position detection result of the rotor by the first and second sensor groups, the excitation phase of the same polarity is formed while overlapping. When the commutation is performed and the magnetic detection element fails, the excitation phase is sequentially switched without overlapping the excitation phases based on the rotational position detection result of the rotor by one of the first and second sensor groups. You may make it perform commutation while doing.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing a configuration of a brushless motor 1 (hereinafter abbreviated as a motor 1) to which a control method of the present invention is applied. The motor 1 is used as a drive source of an electric power steering apparatus, and as shown in FIG. 1, a stator 4 is arranged around a rotor 3 having a rotor magnet 2 (permanent magnet, hereinafter abbreviated as magnet 2). Inner rotor type device configuration. When the driver operates the steering wheel, the motor 1 is controlled and driven in accordance with the steering angle, the traveling speed, and the like, and a steering assist force is supplied to the steering column shaft via a reduction gear (not shown).
[0009]
The rotor 3 includes a rotor core 6 mounted on a metal shaft 5 and a two-pole magnet 2 fixed to the outer periphery of the rotor core 6. The magnet 2 is formed so as to be divided into two segments each made of a ferrite magnet by 180 °. The stator 4 includes a housing 7, a stator core 8 fixed to the inner peripheral side of the housing 7, and an armature coil 9 wound around teeth of the stator core 8. The armature coil 9 forms a three-phase winding of U, V, and W.
[0010]
In the housing 7, a Hall sensor (magnetic detection element) 10 that detects a change in the magnetic pole of the magnet 2 and detects the rotational position of the rotor 3 is provided. FIG. 2 is an explanatory diagram showing an arrangement state of the Hall sensor 10. As shown in FIG. 2, the motor 1 is provided with two sensor groups each having three Hall sensors 10 (sensor groups H1 and H2). The hall sensors 10 are equally spaced at 120 ° intervals for each group, and the sensor group H1 (first sensor group) includes the hall sensors H1a, H1b, H1c, and the sensor group H2 (second sensor group). ) Is composed of Hall sensors H2a, H2b, H2c.
[0011]
The Hall sensors H2a, H2b, H2c of the sensor group H2 are arranged at intervals of X from the Hall sensors H1a, H1b, H1c of the sensor group H1, respectively, and the deviation angle X is within an electrical angle of 0 to 120 °. Is set. The detection signal of the Hall sensor 10 is sent to a controller (energization control means) 11, based on which the current to the armature coil 9 is appropriately switched to form a rotating magnetic field for driving the rotor 3 to rotate. The position of the Hall sensor in a general three-phase brushless motor is located at the center of the sensor groups H1 and H2 (P position in FIG. 2).
[0012]
FIG. 3 is a flowchart showing a motor control mode according to an embodiment of the present invention. As shown in FIG. 3, in the motor 1, the presence or absence of a failure of the Hall sensor 10 is determined (step S1), and if there is no sensor failure, overlap energization control described later is performed (step S2). On the other hand, if there is a failure in the Hall sensor 10, the process proceeds to step S3, and it is detected in which group the failure has occurred. Then, the use of the sensor group including the failed Hall sensor 10 is stopped (steps S4, S6), and the square wave control is performed by the remaining normal sensor group (steps S5, S7).
[0013]
Therefore, the case where the Hall sensor 10 is normal will be described first. FIG. 4 is a time chart showing a control mode when the motor 1 is normally driven when the Hall sensor deviation angle X between the sensor groups H1 and H2 is set to 30 °. In FIG. 4, the upper part shows the signal output of the Hall sensor 10 and the lower part shows the voltage waveform applied to the armature coil 9, in which (a) shows the control mode at the time of normal rotation and (b) shows the control mode at the time of reverse rotation. In addition, the half-moon-shaped figure described above the upper part of (a) schematically shows the position of the rotor 3.
[0014]
In the motor 1, one of the signals from the six Hall sensors H1a, H1b, H1c, H2a, H2b, H2c rises (hereinafter, referred to as ON) or falls (hereinafter, referred to as OFF) during one rotation of the rotor 3. The control mode is divided into 12 stages as shown in FIG. Here, after the Hall sensor H1a (hereinafter, each Hall sensor is indicated only by a symbol like H1a) is turned on, H2a is turned on when the rotor 3 rotates 30 °, and H1c is turned off when the rotor 3 further rotates 30 °. Become. As described above, when X = 30 °, any one of the Hall sensors is turned ON / OFF at intervals of 30 ° with the rotation of the rotor 3, and 12 stages are equally formed. Since the motor 1 is used in forward and reverse rotation, as shown by hatching in FIG. 4, the center of the stage (3) is used as a reference and it is arranged at the center of the U-phase magnetic pole.
[0015]
Here, when the brushless motor is controlled without performing the overlap energization by the three Hall sensors, the coils of each phase are energized in the positive direction of 120 ° → non-energized in 60 ° → energized in the negative direction of 120 ° → non-energized in the direction of 60 °. Repeat the energization. On the other hand, in the motor 1, the armature coil 9 of each phase repeats 150 ° positive direction energization → 30 ° non-energization → 150 ° negative direction energization → 30 ° non-energization, as shown in FIG. The beginning and the end overlap with other phases. That is, in the motor 1, the above-described overlap energization is performed. Thus, a control mode of the motor 1 in a normal state will be described with reference to FIG.
[0016]
First, when the N pole of the rotor 3 is applied to H1a during normal rotation and H1a is turned ON, the U phase is energized in the + direction (hereinafter abbreviated as + energized). At this time, in the W phase, as shown in FIG. 4A, the + energization accompanying the ON of H1c is continued, and the overlap energization is performed when switching from the W phase to the U phase. Such an overlapping energization state of the same polarity is continued until the N pole of the rotor 3 rotates by 30 ° and H2a is turned on (stage (1)). That is, during normal rotation, the overlap time is controlled by H2a, H2b, and H2c while the rotational position of the rotor 3 is detected by H1a, H1b, and H1c. On the other hand, in the stages (1) and (2), only the V phase is energized in the-direction (hereinafter, abbreviated as-energized), and in the stage (1), the U and W phases are + energized and the V phase is energized. In the-energized state, in the stage (2), the U phase is + energized and the V phase is-energized.
[0017]
When the rotor 3 further rotates and becomes the stage (3), H1c is turned off and the W phase is negatively energized. At this time, the-energization of the V phase is continued, and the overlap energization of-is continued until H2c is turned off. When H2c is turned off and the V-phase is de-energized and enters the stage (4), the U-phase is energized and the W-phase is energized. When H1b turns ON and proceeds to stage (5), the V-phase is energized by +. At this time, + energization of the U phase is continued, and overlap energization of + is continued until H2b is turned ON. When H2b is turned on, the U phase is de-energized, the V phase is + energized, the W phase is -energized (stage (6)), and the + energized phase is switched from the U phase to the V phase. . Hereinafter, similarly, the energization state of each phase is switched according to ON / OFF of each of the Hall sensors H1a to H2c, and the normal rotation operation of the rotor 3 is performed.
[0018]
On the other hand, when the rotor 3 rotates in the reverse direction, as shown in FIG. 4B, the control is performed in such a manner that the polarity of the applied voltage is reversed from that in the normal rotation, and the rotation position of the rotor 3 is detected by H2a, H2b, and H2c. Meanwhile, the overlap time is controlled by H1a, H1b, and H1c. For example, when H1a is turned on in stage (6), the U phase is in a non-energized state, and at this time, the W phase is in a positive state and the V phase is in a negative state. When the rotor 3 rotates to the stage (5), H2b is turned off, and the U phase is negatively energized. At this time, in the V phase,-energization (stage (9)) accompanying H2c OFF is continued, and-overlap energization is performed. This state is continued until the rotor 3 is further rotated by 30 ° and H1b is turned off.
[0019]
When the stage (4) is reached, the V phase is de-energized, the W phase is + energized, and the U phase is -energized. In the stage (3), the V-phase is energized with the H2c ON, and the W-phase is energized continuously, and the + overlap energization is continued until the H1c is turned ON. In the stage (2), the W phase is de-energized, the V phase is + energized, the U phase is-energized, and the + energized phase is switched from the W phase to the V phase. In stage (1), the W-phase is energized in accordance with the turning off of H2a. At this time, the energization of the U phase is continued, and the overlap energization of-is continued until H1b is turned off. Hereinafter, similarly, the energization state of each phase is switched according to ON / OFF of each of the Hall sensors H1a to H2c, and the reverse rotation operation of the rotor 3 is performed.
[0020]
The width of the overlap can be changed by appropriately changing the deviation angle X. The overlap amount can be adjusted by setting the deviation angle X. Overlap amount R 1 in FIG. 4 is correlated with the value of X, the overlap amount becomes larger as deviation angle X is greater. Therefore, by adjusting the amount of overlap, it is possible to adopt an optimal control form according to the specifications, and the motor 1 can be applied not only to the electric power steering device but also to a wide range of applications. When the induced voltage waveform of the motor 1 is sinusoidal, the torque ripple becomes a minimum value when the deviation angle X is 30 °.
[0021]
As described above, in the motor 1, overlap energization is performed in the odd-numbered stages, and phase switching, that is, commutation is performed there. Therefore, the commutation is not performed abruptly, and the phase switching is smooth, thereby reducing the torque ripple. In addition, since the control mode, which normally has only six stages, can be changed to 12 stages without adding an estimation, the rotor position detection accuracy is improved, the forward / reverse rotation is severely switched as in an electric power steering device, and the change in acceleration is very large. Overlap current can be adopted in the environment. For this reason, even in an electric power steering device or the like, the drive control of the brushless motor can be performed by an inexpensive Hall sensor without using a resolver or an R / D converter, and the product cost can be reduced.
[0022]
As described above, in the motor 1, when the Hall sensors H1a and the like of the sensor groups H1 and H2 are normal, the overlap energization is performed. On the other hand, if any of the Hall sensors 10 fails, the control mode is changed to the following control mode. That is, taking advantage of the existence of the two sensor groups H1 and H2 in the rotor position detecting device, the sensor group including the faulty sensor is excluded from the control, and the three-phase rectangular wave drive control is performed by the remaining sensor groups. FIG. 5 is a time chart showing a control mode of the motor 1 when H2a fails, for example. The symbols HPa to HPc in the figure indicate the positions of the Hall sensors in a general three-phase brushless motor.
[0023]
When H2a breaks down, the use of the sensor group H2 including this sensor is stopped first. Then, rectangular wave control using H1a to H1c as shown in FIG. 5 is performed by the sensor group H1 not including the failed H2a. In this case, as shown in FIG. 5, the U-phase is energized by turning on H1a, and becomes 0 when H1b is turned on. In the meantime, when H1a and H1c are ON, the V-phase is energized negatively, and when only H1a is ON, the W-phase is energized in the negative direction. When the U-phase becomes 0, the V-phase is energized at the same time, and when H1c turns ON, the V-phase becomes 0 and the W-phase is energized. As described above, the respective phases of the armature coils are sequentially switched and commutated in accordance with ON / OFF of H1a to H1c without overlapping the excitation phases.
[0024]
As shown in FIG. 2, the arrangement of the sensor group H1 is shifted by an angle X / 2 with respect to the sensor arrangement P in a normal three-phase brushless motor. Therefore, as shown in FIG. 5, the signal obtained by the sensor group H1 is also in a state of being advanced (at the time of normal rotation) or retarded (at the time of reverse rotation) by the angle X / 2. Therefore, in the rectangular wave control at the time of failure, the motor is in an advanced or retarded state when the motor is started, but the retarding or advanced angle control is introduced during the rated operation to adjust the control mode of the motor. If the Hall sensor of the sensor group H1 fails, the sensor group H2 is used. In this case, the sensor group is retarded (forward rotation) or advanced (reverse rotation) by the angle X / 2. Is controlled to be advanced or retarded.
[0025]
As described above, in the motor 1, when the Hall sensor is normal, the overlap energization control using the sensor groups H1 and H2 is performed, and when the Hall sensor fails, the sensor group not including the failure sensor is used. Is performed. Therefore, even if the Hall sensor fails, the motor 1 is driven by the remaining remaining normal sensor group as long as it belongs to the same group, so that the motor function is not impaired. For this reason, by using the motor of the present invention, in an electric power steering device, an electronically controlled throttle valve device, and the like, it is possible to provide redundancy for sensor abnormalities, and to improve product reliability. Become.
[0026]
The present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the scope of the invention.
For example, in the above-described embodiment, the configuration has been described in which the sensor groups H1 and H2 are arranged at positions X / 2 apart with respect to the position P of the Hall sensor in a general three-phase brushless motor. Is arbitrary and is not limited to the above-described embodiment. For example, a configuration in which the sensor group H1 (or H2) is arranged at the position P and the sensor group H2 (or H1) is deviated by the angle X is also possible.
[0027]
In the above embodiment, the present invention is applied to a three-phase brushless motor. However, the present invention is applied to other polyphase brushless motors such as a five-phase motor composed of U, V, W, X, and Y. It is also possible to apply Further, in the above-described embodiment, the case where all the three deviation angles X are the same is shown, but various settings such as setting some or all of them to different values are possible. Furthermore, the configuration in which two sets (H1, H2) of the sensor groups are arranged is shown, but three or more sensor groups can be provided.
[0028]
In addition, although the motor 1 is an inner rotor type brushless motor, the present invention can be applied to an outer rotor type brushless motor. Further, the present invention can be applied to a brushless motor that rotates only in one direction without performing forward / reverse rotation. In this case, a proper angle is provided between the center of the stage (3) and the center of the U-phase magnetic pole to advance. Angle control is possible.
[0029]
On the other hand, the above-described embodiment shows an example in which the present invention is applied to a column-assist type electric power steering device. However, the present invention is also applicable to another type of electric power steering device such as a rack assist type. Further, the present invention can be applied to not only an electric power steering device but also an electronically controlled throttle valve device for an engine as disclosed in JP-A-10-184401 and JP-A-10-252510.
[0030]
Further, the brushless motor of the present invention can be applied to uses other than the electric power steering device and the electronically controlled throttle valve device, for example, industrial machines such as robots and IT devices such as personal computers.
[0031]
【The invention's effect】
According to the present invention, in the brushless motor having the first and second sensor groups, when the magnetic detection element fails, the use of the sensor group including the failed magnetic detection element is stopped, and the failed magnetic detection element is included. Since the drive control is performed by another sensor group that does not exist, even if the Hall sensor fails, as long as it belongs to the same group, the motor is driven by the other remaining normal sensor group and the motor function is maintained. It becomes possible. Therefore, by using the motor of the present invention, the electric power steering device, the electronically controlled throttle valve device, and the like can also have redundancy with respect to the sensor abnormality and can improve the reliability of the product. It becomes.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of a brushless motor to which a control method of the present invention is applied.
FIG. 2 is an explanatory diagram showing an arrangement state of a Hall sensor.
FIG. 3 is a flowchart showing a control mode of a brushless motor according to an embodiment of the present invention.
FIG. 4 is a time chart showing a control mode at the time of normal driving of the motor when the Hall sensor deviation angle X between the sensor groups H1 and H2 is set to 30 °, wherein the upper part shows the signal output of the Hall sensor, and the lower part shows the electric motor. 7A and 7B show waveforms of voltages applied to a child coil, wherein FIG. 7A shows a control mode at the time of normal rotation and FIG.
FIG. 5 is a time chart showing a control form of the motor when the Hall sensor H2a fails.
[Explanation of symbols]
Reference Signs List 1 brushless motor 2 rotor magnet 3 rotor 4 stator 5 shaft 6 rotor core 7 housing 8 stator core 9 armature coil 10 Hall sensor H1 first sensor group H2 second sensor group
H1a ~ H1c Hall sensor
H2a to H2c Hall sensor R 1 Overlap amount X Hall sensor deviation angle

Claims (3)

  1. A method for controlling a brushless motor, comprising: a stator having a multi-phase armature coil; and a rotor having a permanent magnet and rotatably disposed inside or outside the stator.
    A first sensor group comprising a plurality of magnetic detection elements arranged on the stator side, detecting a magnetism of the permanent magnet to detect a rotational position of the rotor;
    A second sensor for detecting the rotation of the rotor by detecting the magnetism of the permanent magnet, comprising a plurality of the magnetic detection elements of the first sensor group and a plurality of magnetic detection elements arranged at predetermined intervals. And a sensor group of
    When the magnetic detection elements of the first and second sensor groups fail, the use of the sensor group including the failed magnetic detection element is stopped, and the rotor by the sensor group not including the failed magnetic detection element is used. Controlling the energization of the armature coil based on the rotational position detection result of the above.
  2. 2. The brushless motor control method according to claim 1, wherein when the magnetic detection element fails, the energization of the armature coil is advanced or retarded.
  3. 3. The brushless motor control method according to claim 1, wherein when the magnetic detection element is normal, an excitation phase having the same polarity is set based on a rotation position detection result of the rotor by the first and second sensor groups. 4. When the commutation is performed while forming the overlap, and the magnetic detection element fails, the excitation phase is formed based on the rotational position detection result of the rotor by one of the first and second sensor groups. A brushless motor control method characterized by performing commutation while sequentially switching without switching.
JP2002363042A 2002-12-13 2002-12-13 Brushless motor controlling method Pending JP2004194490A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100440079C (en) * 2007-01-16 2008-12-03 北京航空航天大学 Finite angle driving controller of direct-drive triple redundant brushless DC torque motor
CN102013861A (en) * 2010-09-14 2011-04-13 成都芯源系统有限公司 Direct current (DC) brushless motor system and driving method thereof
CN102826116A (en) * 2011-06-15 2012-12-19 现代摩比斯株式会社 Control method of electric power steering device
CN104029717A (en) * 2013-03-04 2014-09-10 福特环球技术公司 Electric power assist steering motor sensor redundancy
WO2016042607A1 (en) * 2014-09-17 2016-03-24 日本精工株式会社 Electric power steering device
CN105915127A (en) * 2016-06-01 2016-08-31 同济大学 Motor rotor position redundant measuring method and system and electronic device
WO2018132291A1 (en) * 2017-01-10 2018-07-19 Woodward, Inc. Force feel using a brushless dc motor

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100440079C (en) * 2007-01-16 2008-12-03 北京航空航天大学 Finite angle driving controller of direct-drive triple redundant brushless DC torque motor
CN102013861A (en) * 2010-09-14 2011-04-13 成都芯源系统有限公司 Direct current (DC) brushless motor system and driving method thereof
CN102826116A (en) * 2011-06-15 2012-12-19 现代摩比斯株式会社 Control method of electric power steering device
CN104029717A (en) * 2013-03-04 2014-09-10 福特环球技术公司 Electric power assist steering motor sensor redundancy
WO2016042607A1 (en) * 2014-09-17 2016-03-24 日本精工株式会社 Electric power steering device
US9932067B2 (en) 2014-09-17 2018-04-03 Nsk Ltd. Electric power steering apparatus
EP3196096A4 (en) * 2014-09-17 2018-04-18 NSK Ltd. Electric power steering device
CN105915127A (en) * 2016-06-01 2016-08-31 同济大学 Motor rotor position redundant measuring method and system and electronic device
WO2018132291A1 (en) * 2017-01-10 2018-07-19 Woodward, Inc. Force feel using a brushless dc motor
US10074245B2 (en) 2017-01-10 2018-09-11 Woodward, Inc. Force feel using a brushless DC motor

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