CN115411996A - Method for detecting initial position of mechanical arm joint motor - Google Patents

Method for detecting initial position of mechanical arm joint motor Download PDF

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Publication number
CN115411996A
CN115411996A CN202211285441.1A CN202211285441A CN115411996A CN 115411996 A CN115411996 A CN 115411996A CN 202211285441 A CN202211285441 A CN 202211285441A CN 115411996 A CN115411996 A CN 115411996A
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signal
current pulse
controller
mechanical arm
axis
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CN115411996B (en
Inventor
徐炜
段冰
王激尧
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Southeast University
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Southeast University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
    • H02P21/14—Estimation or adaptation of machine parameters, e.g. flux, current or voltage
    • H02P21/18—Estimation of position or speed
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
    • H02P21/24—Vector control not involving the use of rotor position or rotor speed sensors
    • H02P21/32—Determining the initial rotor position
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P2203/00—Indexing scheme relating to controlling arrangements characterised by the means for detecting the position of the rotor
    • H02P2203/03—Determination of the rotor position, e.g. initial rotor position, during standstill or low speed operation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P2207/00—Indexing scheme relating to controlling arrangements characterised by the type of motor
    • H02P2207/05—Synchronous machines, e.g. with permanent magnets or DC excitation

Abstract

The invention provides a method for detecting the initial position of a joint motor of a mechanical arm, which comprises the following steps: randomly selecting d axis to establish dq coordinate system, and injecting basic current pulse signals into four vector angles
Figure 463209DEST_PATH_IMAGE001
Updating the d-axis position according to the duty ratio of the position signal corresponding to each vector angle to obtain an updated d-axis; injecting a first current pulse signal into the updated d-axis
Figure 652882DEST_PATH_IMAGE002
The position type PI controller utilizes the duty ratio of the position signal to carry out feedback control, and controls the output shaft of the mechanical arm joint motor reducer to move towards the nearest minimum resolution scale of the position sensor, so that the absolute value of the duty ratio of the position signal is increased and finally stabilized at the minimum resolution scaleA first predetermined value
Figure 959229DEST_PATH_IMAGE003
(ii) a The position-switched PI controller is an incremental PI controller, and injects a second current pulse signal
Figure 460093DEST_PATH_IMAGE004
To realize the position of d axis
Figure 230603DEST_PATH_IMAGE005
Offset from actual position of motor rotor
Figure 591177DEST_PATH_IMAGE006
Is estimated. The invention is suitable for the mechanical arm joint motor.

Description

Method for detecting initial position of mechanical arm joint motor
Technical Field
The invention belongs to the field of motor control, and particularly relates to a method for detecting an initial position of a joint motor of a mechanical arm.
Background
Compared with the traditional motor, the permanent magnet synchronous motor has the advantages of no need of excitation, small volume, high power density and the like, and is widely applied to occasions such as electric automobiles, numerical control machines, intelligent robots and the like. In the control of the permanent magnet synchronous motor, the motor can be prevented from reversing, the starting torque can be improved and the like by acquiring the accurate initial position of the rotor, and the method is an important step in the control of the motor.
The rotor of the mechanical arm joint motor may rotate after each power failure, when an incremental encoder is used as a position sensor, the initial position of the motor rotor needs to be determined again after each power-on, and the initial position detection scheme based on the incremental position sensor enables the motor rotor to rotate.
Disclosure of Invention
The technical problem is as follows: the invention provides a method for detecting an initial position of a joint motor of a mechanical arm, which aims to solve the problem that the initial position detection difficulty is high by utilizing an incremental encoder after the joint motor of the mechanical arm is restarted after power failure.
The invention has the advantages that the position sensor does not need to be additionally arranged on the output shaft of the joint motor; the detection algorithm is simple to realize; the detection precision is not influenced by the saliency of the motor.
The technical scheme is as follows: in order to realize the purpose, the technical scheme adopted by the invention is as follows:
a method for detecting the initial position of a joint motor of a mechanical arm comprises the following steps:
the detection method comprises the following steps that a position sensor is installed on an output shaft of a mechanical arm joint motor reducer, a motor control driver controls the output shaft of the mechanical arm joint motor reducer to rotate, the position sensor outputs a position signal by capturing the rotation of the output shaft, and based on the duty ratio of the position signal, initial position detection of a mechanical arm joint motor is carried out by using a position type PI controller, an incremental type PI controller and a current pulse signal, and the detection method comprises the following steps:
step S1: randomly selecting d axis to establish dq coordinate system, and injecting basic current pulse signals to four vector angle directions
Figure 278010DEST_PATH_IMAGE001
Updating the d-axis position according to the duty ratio of the position signal corresponding to each vector angle to obtain an updated d-axis
Figure 800258DEST_PATH_IMAGE002
；
S1-1, randomly selecting a d axis to establish a dq coordinate system, and sequentially selecting four vector angles under the dq coordinate system
Figure 108880DEST_PATH_IMAGE003
，
Figure 261644DEST_PATH_IMAGE004
；
Step S1-2, angle to the vector
Figure 22926DEST_PATH_IMAGE003
Injecting a basic current pulse signal
Figure 348866DEST_PATH_IMAGE001
Obtaining a signal of injecting a basic current pulse at each vector angle
Figure 511994DEST_PATH_IMAGE001
The duty cycle of the latter position signal, wherein,
Figure 632396DEST_PATH_IMAGE001
is defined as follows:
Figure 146554DEST_PATH_IMAGE005
，
in the formula (I), the compound is shown in the specification,
Figure 273255DEST_PATH_IMAGE006
is the d-axis initial current value;
Figure 25310DEST_PATH_IMAGE007
is a basic current pulse signal
Figure 582193DEST_PATH_IMAGE001
A period of (a);
step S1-3, updating d axis position to
Figure 318068DEST_PATH_IMAGE002
，
Figure 985810DEST_PATH_IMAGE008
In the formula (I), wherein,
Figure 857951DEST_PATH_IMAGE009
to achieve the corresponding vector angle at maximum duty cycle,
Figure 585735DEST_PATH_IMAGE010
is the maximum duty cycle;
Figure 808906DEST_PATH_IMAGE011
is a standard symbolic function, defined as
Figure 280339DEST_PATH_IMAGE012
；
Step S2: to the updated d-axis
Figure 272566DEST_PATH_IMAGE002
Injecting a first current pulse signal
Figure 171252DEST_PATH_IMAGE013
The position type PI controller carries out feedback control by measuring and calculating the duty ratio of the position signal, and controls the output shaft of the mechanical arm joint motor reducer to move towards the nearest minimum resolution scale of the position sensor, so that the absolute value of the duty ratio of the position signal is increased and finally stabilized at a first preset value
Figure 84981DEST_PATH_IMAGE014
；
Step S2-1, continuously updating the updated d axis
Figure 94525DEST_PATH_IMAGE002
Injecting a first current pulse signal
Figure 206838DEST_PATH_IMAGE013
Obtaining the injected first current pulse signal
Figure 10846DEST_PATH_IMAGE013
The duty cycle of the latter position signal, wherein,
Figure 35757DEST_PATH_IMAGE013
is defined as
Figure 583413DEST_PATH_IMAGE015
In the formula (I), wherein,
Figure 753495DEST_PATH_IMAGE016
for calculating the first current pulse signal
Figure 728404DEST_PATH_IMAGE013
The amount of time shift required;
s2-2, the position type PI controller takes the duty ratio as feedback quantity to carry out closed-loop control, and outputs and calculates a first current pulse signal
Figure 679042DEST_PATH_IMAGE013
The amount of time shift required
Figure 30389DEST_PATH_IMAGE016
To stabilize the duty cycle at a first predetermined value
Figure 851715DEST_PATH_IMAGE014
；
And step S3: the position-switching PI controller is an incremental PI controller, and the updated d-axis position is realized
Figure 263105DEST_PATH_IMAGE002
Offset from actual position of motor rotor
Figure 169881DEST_PATH_IMAGE017
Is estimated by
Figure 59339DEST_PATH_IMAGE018
；
S3-1, cutting off the position type PI controller and putting into an incremental type PI controller, and injecting the first current pulse signal
Figure 204013DEST_PATH_IMAGE013
Switching to the second current pulse signal
Figure 520725DEST_PATH_IMAGE019
In which
Figure 914797DEST_PATH_IMAGE019
Is defined as
Figure 607946DEST_PATH_IMAGE020
；
S3-2, the incremental PI controller performs closed-loop control by taking the duty ratio as a feedback quantity and outputs the position of the d axis
Figure 666514DEST_PATH_IMAGE021
Offset from actual position of motor rotor
Figure 419706DEST_PATH_IMAGE017
Is estimated by
Figure 301074DEST_PATH_IMAGE018
Until the duty cycle stabilizes at a second predetermined value
Figure 532336DEST_PATH_IMAGE022
And finishing the detection of the initial position of the motor rotor.
The four vector angles
Figure 917180DEST_PATH_IMAGE003
Sequentially differ by 90 °; one of the two vector angles is a randomly selected vector angle, and the other three vector angles are different from the randomly selected vector angles by 90 degrees, 180 degrees and 270 degrees respectively.
The basic current pulse signal
Figure 106853DEST_PATH_IMAGE001
Designed as positive and negative pulse signals, the average torque and average rotation angle of the current generated on the rotor of the motor
Figure 475518DEST_PATH_IMAGE023
Are all 0, and the position of the motor rotor in a static state is not changed.
The initial position detection, before the detection, the d-axis initial current value in the step S1-2
Figure 510470DEST_PATH_IMAGE006
And a basic current pulse signal
Figure 15401DEST_PATH_IMAGE001
Period of (2)
Figure 110396DEST_PATH_IMAGE007
Can pass through a relational expression
Figure 966356DEST_PATH_IMAGE024
Evaluating to obtain multiple reference value pairs<
Figure 539420DEST_PATH_IMAGE025
>In which J is electricityCombined moment of inertia of the machine and load;
Figure 164436DEST_PATH_IMAGE026
the transmission ratio of the mechanical arm joint motor reducer is obtained;
Figure 430333DEST_PATH_IMAGE027
resolution of the position sensor;
Figure 508010DEST_PATH_IMAGE028
the number of pole pairs of the permanent magnet of the motor;
Figure 150344DEST_PATH_IMAGE029
is a permanent magnet flux linkage.
The position signal is a jump signal of a square wave type formed by the shake of an output shaft of the mechanical arm joint motor reducer near the minimum resolution scale of the position sensor and captured by the position sensor;
according to different movement directions of the motor, the value range of the square wave type jump signal is { x, x +1} or { x, x-1}, wherein x is an initial detection value of the position sensor; the proportion of x +1 or x-1 in the jump signal of the square wave type is defined as the duty ratio of a position signal;
when the value of the jumping signal of the square wave type is x +1, the jumping signal is defined as the positive direction of the duty ratio, and the duty ratio takes the positive value at the moment; and when the value of the hopping signal of the square wave type is x-1, defining the duty ratio at the moment as a negative direction and taking a negative value.
In the step S2-2, the output calculates a first current pulse signal
Figure 632796DEST_PATH_IMAGE013
The amount of time shift required
Figure 69594DEST_PATH_IMAGE016
Will be
Figure 837830DEST_PATH_IMAGE016
Is limited to
Figure 752696DEST_PATH_IMAGE030
。
In the step S2-2, the first predetermined value
Figure 352305DEST_PATH_IMAGE014
Is provided with
Figure 960004DEST_PATH_IMAGE031
，
Figure 12273DEST_PATH_IMAGE032
Defaults to 0.05; the control deviation of the position type PI controller is
Figure 730831DEST_PATH_IMAGE033
Wherein, in the process,
Figure 184946DEST_PATH_IMAGE034
is the duty cycle of the position signal; along with the output shaft of the mechanical arm joint motor reducer continuously moves to the minimum resolution scale of the nearest position sensor, the control deviation of the position type PI controller is continuously reduced, and the absolute value of the duty ratio of the position signal is finally stabilized at a first preset value
Figure 963546DEST_PATH_IMAGE014
。
In the step S3-2, the d-axis position is output at the k iteration
Figure 503112DEST_PATH_IMAGE035
Offset from actual position of motor rotor
Figure 290939DEST_PATH_IMAGE036
Is estimated by
Figure 599561DEST_PATH_IMAGE037
Update the d-axis position as
Figure 549062DEST_PATH_IMAGE038
(ii) a The incremental PI controlIntegration of the output of the generator
Figure 310345DEST_PATH_IMAGE039
Will be limited to
Figure 633354DEST_PATH_IMAGE040
And the operation of magnetic pole detection on the motor rotor is omitted.
In the step S3-2, the second predetermined value
Figure 796482DEST_PATH_IMAGE022
Is provided with
Figure 916885DEST_PATH_IMAGE041
，
Figure 431043DEST_PATH_IMAGE042
Defaults to 0.05; the control deviation of the incremental PI controller is
Figure 498356DEST_PATH_IMAGE043
Wherein, in the step (A),
Figure 515991DEST_PATH_IMAGE034
is the duty cycle of the position signal; when the duty cycle of the position signal is close
Figure 72874DEST_PATH_IMAGE022
Time of second current pulse signal
Figure 605486DEST_PATH_IMAGE019
The amplitude of the induced motor rotor rotation approximates the range size of the position sensor hysteresis characteristics.
The incremental PI controller adopts a variable coefficient method to exponentially amplify or reduce the control coefficient so as to meet the precision requirement of position detection.
Has the beneficial effects that: the beneficial effects of the invention are embodied in the following aspects:
(a) The invention belongs to a static motor rotor initial position detection method, which ensures that a motor rotor is in a quasi-static state by limiting the maximum rotation angle of the motor rotor to be less than 2 times of the resolution of a position sensor, and completes the detection of the initial position of the motor rotor.
(b) Compared with the conventional method, the method is the motor rotor initial position detection method based on the position signal duty ratio, the method does not depend on the saliency of the motor, and the detection precision is not influenced by the saliency.
(c) According to the invention, the estimation value of the initial position of the motor rotor is preliminarily limited by updating the initial randomly selected dq coordinate system, so that the controller can only converge to the correct rotor magnetic pole direction in the subsequent detection process, the rotor magnetic pole does not need to be distinguished, and the detection process is simplified.
Drawings
FIG. 1 is a flow chart of a method of detecting an initial position of a motor;
FIG. 2 is a schematic diagram of four random vector angles and a d-axis initial position;
fig. 3 is a schematic diagram of a position PI controller and an incremental PI controller.
The drawing comprises the following steps: the controller comprises a current pulse signal 10, a position type PI controller 20, an incremental type PI controller 30, a motor control driver 40, a mechanical arm joint motor reducer 50 and a position sensor 60.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.
As shown in fig. 1, the method for detecting the initial position of the mechanical arm joint motor according to the embodiment of the present invention includes the following steps:
s1: determining the d-axis position: randomly selecting d axis to establish dq coordinate system, and injecting basic current pulse signals to four vector angle directions
Figure 7649DEST_PATH_IMAGE001
And updating the d-axis position according to the duty ratio of the position signal corresponding to each vector angle.
The step S1 specifically includes:
(1) Randomly selecting d-axis to establish dq coordinate system, under the dq coordinate system, four vector angles are selected in turn
Figure 145369DEST_PATH_IMAGE003
(n=1,2,3,4)；
(2) To the vector angle
Figure 76416DEST_PATH_IMAGE003
Injecting a basic current pulse signal
Figure 34008DEST_PATH_IMAGE001
Obtaining a signal of injecting a basic current pulse at each vector angle
Figure 505440DEST_PATH_IMAGE001
The duty cycle of the latter position signal, wherein,
Figure 497667DEST_PATH_IMAGE001
is defined as follows:
Figure 130774DEST_PATH_IMAGE005
，
in the formula (I), the compound is shown in the specification,
Figure 832452DEST_PATH_IMAGE006
is the d-axis initial current value;
Figure 841996DEST_PATH_IMAGE007
is a basic current pulse signal
Figure 688729DEST_PATH_IMAGE001
A period of (a);
(3) Update d-axis position to
Figure 758317DEST_PATH_IMAGE002
，
Figure 159342DEST_PATH_IMAGE008
In the formula (I), the reaction is carried out,
Figure 972577DEST_PATH_IMAGE009
to achieve the corresponding vector angle at maximum duty cycle,
Figure 939396DEST_PATH_IMAGE010
is the maximum duty cycle;
Figure 914306DEST_PATH_IMAGE011
is a standard symbolic function and is defined as
Figure 599365DEST_PATH_IMAGE012
；
Fig. 2 shows the positional relationship between the four vector angles and the rotor of the motor in the dq coordinate system before and after the step S1 is performed,
Figure 950712DEST_PATH_IMAGE044
for randomly selected vector angles, four vector angles
Figure 772037DEST_PATH_IMAGE003
Corresponding to four directions
Figure 183427DEST_PATH_IMAGE045
Satisfy the relation of 90 degrees difference in sequence. Injecting basic current pulse signals into four vector angles respectively
Figure 90203DEST_PATH_IMAGE001
Taking fig. 2 as an example, assuming that the actual position of the rotor coincides with the d-axis, the randomness of the initial position of the output shaft of the encoder is considered
Figure 979662DEST_PATH_IMAGE046
、
Figure 655494DEST_PATH_IMAGE047
Wherein the maximum duty ratio is obtained under one vector angle according to the calculation formula
Figure 500434DEST_PATH_IMAGE008
Can be obtained in
Figure 628927DEST_PATH_IMAGE048
When the maximum duty ratio is obtained, the initial position of the d axis is updated
Figure 587656DEST_PATH_IMAGE002
Is composed of
Figure 117994DEST_PATH_IMAGE049
(ii) a In that
Figure 136766DEST_PATH_IMAGE047
When the maximum duty ratio is obtained, the initial position of the d axis is updated
Figure 486976DEST_PATH_IMAGE002
Is composed of
Figure 249396DEST_PATH_IMAGE050
。
In one embodiment, according to a formula
Figure 899820DEST_PATH_IMAGE024
Estimating and selecting a pair<
Figure 823913DEST_PATH_IMAGE025
>Is composed of<10A, 0.01s>. By using the edge detection function of the STM32F407 micro-control unit, the jump edge of the position signal is recorded and then the basic current pulse signal is used
Figure 192578DEST_PATH_IMAGE001
Period of (2)
Figure 227530DEST_PATH_IMAGE007
The duty cycle of the position signal can be calculated.
S2: special positioning of the rotor: the position type PI controller performs feedback control by using the duty ratio of the position signal, and controls the output shaft of the mechanical arm joint motor reducer to move towards the nearest minimum resolution scale of the position sensor, so that the absolute value of the duty ratio of the position signal is increased and finally stabilized at a first preset value
Figure 732461DEST_PATH_IMAGE014
。
The step S2 specifically includes:
(1) Continuously to the updated d-axis
Figure 827456DEST_PATH_IMAGE002
Injecting a first current pulse signal
Figure 417837DEST_PATH_IMAGE013
Obtaining the injected first current pulse signal
Figure 256480DEST_PATH_IMAGE013
The duty cycle of the latter position signal, wherein,
Figure 881496DEST_PATH_IMAGE013
is defined as
Figure 150322DEST_PATH_IMAGE015
In the formula (I), wherein,
Figure 228000DEST_PATH_IMAGE016
for calculating the first current pulse signal
Figure 604754DEST_PATH_IMAGE013
The amount of time shift required;
(2) The position PI controller performs closed-loop control by using the duty ratio as a feedback quantity, and outputs and calculates a first current pulse signal
Figure 84277DEST_PATH_IMAGE013
The amount of time shift required
Figure 521075DEST_PATH_IMAGE016
Stabilizing the duty cycle at a first predetermined value
Figure 86048DEST_PATH_IMAGE014
；
As shown in fig. 3, includes: current pulse signal 10 and position type PI controller20. An incremental PI controller 30, a motor control driver 40, a mechanical arm joint motor reducer 50 and a position sensor 60; when the position type PI controller works, the incremental PI controller is not connected into the initial position detection system, and the position type PI controller calculates a first current pulse signal through output
Figure 266494DEST_PATH_IMAGE013
The amount of time shift required
Figure 866103DEST_PATH_IMAGE016
Controlling the first current pulse signal
Figure 473801DEST_PATH_IMAGE013
The average torque which is not 0 and is generated on the motor rotor is further controlled to move the minimum resolution scale of the position sensor closest to the output shaft of the mechanical arm joint motor reducer, so that the absolute value of the duty ratio of the position signal is increased and finally stabilized at a first preset value
Figure 260492DEST_PATH_IMAGE014
In one embodiment, the first predetermined value
Figure 244628DEST_PATH_IMAGE014
Set to 0.95.
S3: estimating the initial position of the motor: the position-switching PI controller is an incremental PI controller, and feedback control is performed by using the duty ratio of the position signal to control the position of the d-axis
Figure 698744DEST_PATH_IMAGE021
Offset from actual position of motor rotor
Figure 477344DEST_PATH_IMAGE017
And (6) estimating.
Step S3 specifically includes:
(1) Cutting off the position PI controller and putting into the incremental PI controller to inject the first current pulse signal
Figure 751330DEST_PATH_IMAGE013
Switching to the second current pulse signal
Figure 273578DEST_PATH_IMAGE019
Wherein
Figure 582200DEST_PATH_IMAGE019
Is defined as
Figure 528772DEST_PATH_IMAGE020
；
(2) The incremental PI controller performs closed-loop control by using the duty ratio as a feedback quantity and outputs the position of the d axis
Figure 555634DEST_PATH_IMAGE021
Offset from actual position of motor rotor
Figure 615993DEST_PATH_IMAGE017
Is estimated by
Figure 44701DEST_PATH_IMAGE018
Until the duty cycle stabilizes at a second predetermined value
Figure 165104DEST_PATH_IMAGE022
And finishing the detection of the initial position of the motor rotor.
As shown in FIG. 3, the incremental PI controller outputs the offset between the d-axis and the actual position of the motor rotor
Figure 413682DEST_PATH_IMAGE017
Is estimated by
Figure 277733DEST_PATH_IMAGE018
. After step S1 is executed, the d-axis initial position
Figure 560947DEST_PATH_IMAGE002
Offset from actual position of motor rotor
Figure 852251DEST_PATH_IMAGE051
Therefore, the integral value output by the incremental PI controller is
Figure 588126DEST_PATH_IMAGE052
In one embodiment, the second predetermined value
Figure 255867DEST_PATH_IMAGE022
Set to 0.5.

Claims (10)

1. The method for detecting the initial position of the mechanical arm joint motor is characterized in that a position sensor (60) is mounted on an output shaft of a mechanical arm joint motor reducer (50), a motor control driver (40) controls the rotation of the output shaft of the mechanical arm joint motor reducer (50), the position sensor (60) outputs a position signal by capturing the rotation of the output shaft, and based on the duty ratio of the position signal, the initial position detection method of the mechanical arm joint motor is carried out by using a position type PI controller (20), an incremental type PI controller (30) and a current pulse signal (10), and the method specifically comprises the following steps:
step S1: randomly selecting d axis to establish dq coordinate system, and injecting basic current pulse signals to four vector angle directions
Figure 155710DEST_PATH_IMAGE001
Updating the d-axis position according to the duty ratio of the position signal corresponding to each vector angle to obtain an updated d-axis
Figure 194686DEST_PATH_IMAGE002
；
S1-1, randomly selecting a d axis to establish a dq coordinate system, and sequentially selecting four vector angles under the dq coordinate system
Figure 85281DEST_PATH_IMAGE003
，
Figure 554440DEST_PATH_IMAGE004
；
Step S1-2, angle to the vector
Figure 897697DEST_PATH_IMAGE005
Injecting a basic current pulse signal
Figure 743293DEST_PATH_IMAGE006
Obtaining a basic current pulse signal injected at each vector angle
Figure 691657DEST_PATH_IMAGE006
The duty cycle of the latter position signal, wherein,
Figure 331717DEST_PATH_IMAGE006
is defined as follows:
Figure 162270DEST_PATH_IMAGE007
，
in the formula (I), the compound is shown in the specification,
Figure 545978DEST_PATH_IMAGE008
is the d-axis initial current value;
Figure 145586DEST_PATH_IMAGE009
is a basic current pulse signal
Figure 959477DEST_PATH_IMAGE006
A period of (c);
step S1-3, updating d axis position to
Figure 277326DEST_PATH_IMAGE010
，
Figure 464725DEST_PATH_IMAGE011
In the formula (I), wherein,
Figure 653261DEST_PATH_IMAGE012
to achieve the corresponding vector angle at maximum duty cycle,
Figure 697440DEST_PATH_IMAGE013
is the maximum duty cycle;
Figure 440268DEST_PATH_IMAGE014
is a standard symbolic function, defined as
Figure 228096DEST_PATH_IMAGE015
；
Step S2: to the updated d-axis
Figure 536717DEST_PATH_IMAGE010
Injecting a first current pulse signal
Figure 955060DEST_PATH_IMAGE016
The position type PI controller (20) carries out feedback control by measuring and calculating the duty ratio of the position signal, and controls the output shaft of the mechanical arm joint motor reducer (50) to move towards the minimum resolution scale of the nearest position sensor, so that the absolute value of the duty ratio of the position signal is increased and finally stabilized at a first preset value
Figure 981922DEST_PATH_IMAGE017
；
Step S2-1, continuously updating the updated d axis
Figure 245544DEST_PATH_IMAGE010
Injecting a first current pulse signal
Figure 674252DEST_PATH_IMAGE016
Obtaining the first current pulse signal
Figure 260566DEST_PATH_IMAGE016
The duty cycle of the latter position signal, wherein,
Figure 509145DEST_PATH_IMAGE016
is defined as
Figure 638775DEST_PATH_IMAGE018
In the formula (I), wherein,
Figure 125251DEST_PATH_IMAGE019
for calculating the first current pulse signal
Figure 682135DEST_PATH_IMAGE016
The amount of time shift required;
s2-2, the position type PI controller (20) performs closed-loop control by using the duty ratio as a feedback quantity, and the position type PI controller (20) outputs and calculates a first current pulse signal
Figure 418009DEST_PATH_IMAGE016
The amount of time shift required
Figure 289013DEST_PATH_IMAGE019
Stabilizing the duty cycle at a first predetermined value
Figure 426734DEST_PATH_IMAGE017
；
And step S3: the position switching type PI controller (20) is an incremental PI controller (30) and realizes the position of the d shaft
Figure 154518DEST_PATH_IMAGE020
Offset from actual position of motor rotor
Figure 377689DEST_PATH_IMAGE021
Is estimated by
Figure 583543DEST_PATH_IMAGE022
；
S3-1, cutting off the position type PI controller (20) and putting in an incremental type PAn I controller (30) for injecting the first current pulse signal
Figure 310190DEST_PATH_IMAGE016
Switching to the second current pulse signal
Figure 474455DEST_PATH_IMAGE023
Wherein
Figure 176133DEST_PATH_IMAGE023
Is defined as
Figure 920098DEST_PATH_IMAGE024
；
S3-2, the incremental PI controller (30) performs closed-loop control by taking the duty ratio as a feedback quantity and outputs the position of the d axis
Figure 32411DEST_PATH_IMAGE020
Offset from actual position of motor rotor
Figure 836419DEST_PATH_IMAGE021
Is estimated by
Figure 34182DEST_PATH_IMAGE022
Until the duty cycle stabilizes at a second predetermined value
Figure 581838DEST_PATH_IMAGE025
And finishing the detection of the initial position of the motor rotor.
2. The method for detecting the initial position of the mechanical arm joint motor according to claim 1, wherein in the step S1-1, the four vector angles
Figure 548657DEST_PATH_IMAGE005
Sequentially differ by 90 °; one is a randomly selected vector angle, and the other three are respectively the randomly selected vector anglesThe difference is 90 degrees, 180 degrees and 270 degrees.
3. The method for detecting the initial position of a robot arm joint motor according to claim 1, wherein the basic current pulse signal is a basic current pulse signal
Figure 789145DEST_PATH_IMAGE006
Designed as positive and negative pulse signals, the average torque and average rotation angle of the current generated on the rotor of the motor
Figure 208625DEST_PATH_IMAGE026
All are 0, and the position of the motor rotor in a static state is not changed.
4. The method for detecting the initial position of the mechanical arm joint motor according to claim 1, wherein the initial position is detected, and before the detection, the d-axis initial current value in the step S1-2 is detected
Figure 559972DEST_PATH_IMAGE008
And a basic current pulse signal
Figure 381298DEST_PATH_IMAGE006
Period of (2)
Figure 792688DEST_PATH_IMAGE009
By means of a relational expression
Figure 699464DEST_PATH_IMAGE027
Evaluating to obtain multiple reference value pairs<
Figure 588922DEST_PATH_IMAGE028
>Wherein J is the combined moment of inertia of the motor and the load;
Figure 530333DEST_PATH_IMAGE029
the transmission ratio of a mechanical arm joint motor reducer (50);
Figure 112625DEST_PATH_IMAGE030
is the resolution of the position sensor (60);
Figure 707029DEST_PATH_IMAGE031
the number of pole pairs of the permanent magnet of the motor is set;
Figure 196917DEST_PATH_IMAGE032
is a permanent magnet flux linkage.
5. The method for detecting the initial position of the mechanical arm joint motor according to claim 1, wherein the position signal is a jump signal of a square wave type formed by the shake of the output shaft of the mechanical arm joint motor reducer (50) near the minimum resolution scale of the position sensor (60) and captured by the position sensor (60);
according to different movement directions of the motor, the value range of the jump signal of the square wave type is { x, x +1} or { x, x-1}, wherein x is an initial detection value of the position sensor (60); the proportion of x +1 or x-1 in the jump signal of the square wave type is defined as the duty ratio of a position signal;
when the value of the jumping signal of the square wave type is x +1, the jumping signal is defined as the positive direction of the duty ratio, and the duty ratio takes the positive value at the moment; and when the value of the hopping signal of the square wave type is x-1, defining the duty ratio at the moment as a negative direction and taking a negative value.
6. The method for detecting the initial position of the joint motor of the robot arm as claimed in claim 1, wherein the outputting calculates the first current pulse signal in the step S2-2
Figure 727255DEST_PATH_IMAGE016
The amount of time shift required
Figure 480447DEST_PATH_IMAGE019
Will be
Figure 565078DEST_PATH_IMAGE019
Is limited to
Figure 61918DEST_PATH_IMAGE033
。
7. The method for detecting the initial position of the mechanical arm joint motor according to claim 1, wherein in the step S2-2, the first predetermined value is set
Figure 712343DEST_PATH_IMAGE017
Is provided with
Figure 370857DEST_PATH_IMAGE034
，
Figure 739522DEST_PATH_IMAGE035
Defaults to 0.05; the control deviation of the position type PI controller (20) is
Figure 774474DEST_PATH_IMAGE036
Wherein, in the process,
Figure 544984DEST_PATH_IMAGE037
is the duty cycle of the position signal; as the output shaft of the mechanical arm joint motor reducer (50) continuously moves to the minimum resolution scale of the nearest position sensor (60), the control deviation of the position type PI controller (20) is continuously reduced, and the absolute value of the duty ratio of the position signal is finally stabilized at a first preset value
Figure 639979DEST_PATH_IMAGE017
。
8. The method for detecting the initial position of the mechanical arm joint motor according to claim 1, wherein in the step S3-2, a d-axis position is output
Figure 495939DEST_PATH_IMAGE020
Offset from actual position of motor rotor
Figure 334582DEST_PATH_IMAGE021
Is estimated by
Figure 694019DEST_PATH_IMAGE022
Outputting d-axis position at kth iteration
Figure 962845DEST_PATH_IMAGE038
Offset from actual position of motor rotor
Figure 40523DEST_PATH_IMAGE039
Is estimated by
Figure 682857DEST_PATH_IMAGE040
Update the d-axis position to
Figure 162379DEST_PATH_IMAGE041
(ii) a Integration of the output of the incremental PI controller (30)
Figure 599177DEST_PATH_IMAGE042
Will be limited to
Figure 164151DEST_PATH_IMAGE043
And the operation of magnetic pole detection on the motor rotor is omitted.
9. The method for detecting the initial position of a robot arm joint motor according to claim 1, wherein in step S3-2, the second predetermined value is set
Figure 344596DEST_PATH_IMAGE025
Is provided with
Figure 678626DEST_PATH_IMAGE044
，
Figure 286324DEST_PATH_IMAGE045
Defaults to 0.05; the control deviation of the incremental PI controller (30) is
Figure 338594DEST_PATH_IMAGE046
Wherein, in the step (A),
Figure 57151DEST_PATH_IMAGE047
is the duty cycle of the position signal; when the duty cycle of the position signal is close to
Figure 511266DEST_PATH_IMAGE025
Time of second current pulse signal
Figure 289867DEST_PATH_IMAGE023
The resulting amplitude of the motor rotor rotation approximates the magnitude of the hysteresis characteristic of the position sensor (60).
10. The method for detecting the initial position of the mechanical arm joint motor according to claim 8, wherein the incremental PI controller (30) adopts a variable coefficient method, and exponentially enlarges or reduces the control coefficient to meet the accuracy requirement of position detection.
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Citations (4)

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Publication number Priority date Publication date Assignee Title
CN101714844A (en) * 2009-11-10 2010-05-26 哈尔滨工业大学 Method for detecting initial position of magnetic pole of rotor of built-in permanent magnetic synchronous motor
CN102931903A (en) * 2012-10-18 2013-02-13 青岛斑科变频技术有限公司 Method for detecting initial position of rotor of permanent magnet synchronous motor
CN111464105A (en) * 2020-05-15 2020-07-28 华中科技大学 Method for detecting initial position of permanent magnet synchronous motor
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Publication number Priority date Publication date Assignee Title
CN101714844A (en) * 2009-11-10 2010-05-26 哈尔滨工业大学 Method for detecting initial position of magnetic pole of rotor of built-in permanent magnetic synchronous motor
CN102931903A (en) * 2012-10-18 2013-02-13 青岛斑科变频技术有限公司 Method for detecting initial position of rotor of permanent magnet synchronous motor
CN111464105A (en) * 2020-05-15 2020-07-28 华中科技大学 Method for detecting initial position of permanent magnet synchronous motor
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