CN111342716A - Control method and control circuit of holder and related device - Google Patents
Control method and control circuit of holder and related device Download PDFInfo
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- CN111342716A CN111342716A CN202010244968.4A CN202010244968A CN111342716A CN 111342716 A CN111342716 A CN 111342716A CN 202010244968 A CN202010244968 A CN 202010244968A CN 111342716 A CN111342716 A CN 111342716A
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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
- H02P8/00—Arrangements for controlling dynamo-electric motors of the kind having motors rotating step by step
- H02P8/36—Protection against faults, e.g. against overheating, step-out; Indicating faults
- H02P8/38—Protection against faults, e.g. against overheating, step-out; Indicating faults the fault being step-out
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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
- H02P8/00—Arrangements for controlling dynamo-electric motors of the kind having motors rotating step by step
- H02P8/02—Arrangements for controlling dynamo-electric motors of the kind having motors rotating step by step specially adapted for single-phase or bi-pole stepper motors, e.g. watch-motors, clock-motors
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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
- H02P8/00—Arrangements for controlling dynamo-electric motors of the kind having motors rotating step by step
- H02P8/12—Control or stabilisation of current
Abstract
The invention discloses a control method of a cloud platform, a control circuit and a related device thereof, wherein the control method of the cloud platform comprises the following steps: firstly, acquiring the motion state of a cloud deck, and detecting whether the cloud deck is out of step in different modes by judging whether the motion state of the cloud deck is a static state; when the motion state of the holder is not a static state, judging whether the holder is out of step or not through the synthetic current of a motor of the holder; when the motion state of the cradle head is a static state, judging whether the cradle head is out of step or not through single-phase current of the motor; and if the tripod head is judged to be out of step, carrying out the out-of-step correction of the tripod head. Through the mode, the step-out condition of the holder is judged according to different motion states of the holder and the synthetic current and the single-phase current of the holder motor respectively, so that the detection process has a certain degree of pertinence, the detection method is simple and effective, and the real-time performance and the accuracy of the step-out detection of the holder are improved.
Description
Technical Field
The present invention relates to the field of electronic technologies, and in particular, to a control method and a control circuit for a pan/tilt head, and a related apparatus.
Background
With the development of science and technology, various pan-tilt cameras continuously appear in the visual field of people. At present, most of pan-tilt cameras drive the cameras on the pan-tilt to rotate through a motor and a transmission chain. Among them, the stepping motor is widely used in the pan-tilt camera because of its advantages of relatively simple control, low cost, no need of a position sensor to convert a motion angle, and the like.
The stepping motor is an open-loop control element for converting an electric pulse signal into angular displacement or linear displacement. The pan-tilt adopting the open-loop stepping motor is easy to cause the pan-tilt to lose step (lose pulse signals) when being subjected to external force impact (such as shaking or vibration), overlarge load (such as strong wind or artificial external force application) and high-speed moment attenuation and the like, and finally the position of the pan-tilt is inconsistent with the actual position, so that the problem that the picture of a camera on the pan-tilt deviates from the original monitoring target area occurs.
At present, in order to solve the above problems, one approach adopted in the industry is: a position encoder is added at the tail end of a motor on the holder or the tail end of the holder to form semi-closed loop or full-closed loop feedback, so that whether the holder is out of step or not is judged by detecting whether a position difference occurs between an actual position and a reference position through a position sensor; II, secondly: whether the cradle head is out of step or not is judged by detecting and counting the variance value of the current. However, in one of the above two methods, the step-out detection needs an additional position encoder, which is expensive and the higher the accuracy of the position encoder is. Secondly, the accuracy and reliability of the variance statistic value are ensured, and the current data in a period of time needs to be continuously counted, so that the data volume of the collection and the processing is large, and the time for judging the step loss is relatively long.
Disclosure of Invention
The invention provides a control method of a holder, a control circuit thereof and a related device, which are used for solving the problems of high cost and long time consumption of holder step-out detection in the prior art.
In order to solve the above technical problem, the present invention provides a method for controlling a pan/tilt head, comprising: acquiring the motion state of the holder, and judging whether the motion state is a static state; if the motion state is not the static state, judging whether the cradle head is out of step through the synthetic current of a motor of the cradle head, and if the motion state is the static state, judging whether the cradle head is out of step through the single-phase current of the motor; and if the cradle head is out of step, performing out-of-step correction.
Wherein, the step of judging whether the cloud platform is out of step through the synthetic current of the motor of cloud platform includes: acquiring first data of a holder, and calculating to obtain a first theoretical synthetic current of a motor based on the first data; acquiring real-time single-phase currents of the motor in a motion state through an analog-digital converter; summing the square values of the single-phase currents to obtain the real-time square value of the synthesized current in the motor motion state; and comparing the difference value between the square value of the synthetic current and the square value of the first theoretical synthetic current with a first preset threshold value to judge whether the holder is out of step.
The method comprises the following steps of obtaining first data of a holder, and calculating to obtain a first theoretical synthetic current of a motor based on the first data, wherein the step comprises the following steps of: acquiring first data, and calculating to obtain phase current sine wave angular frequency and impedance of the motor based on the first data; acquiring a driving voltage of the motor, and acquiring second data of the motor based on a driving model of the motor; wherein the second data comprises: the load angle, the phase lag angle, the back electromotive force constant and the impedance-related angle of the motor; and calculating to obtain a first theoretical composite current by using the driving voltage, the phase current sine wave angular frequency, the second data and the impedance.
The steps of acquiring first data and calculating phase current sine wave angular frequency and impedance of the motor based on the first data specifically comprise: acquiring a pan-tilt transmission ratio, a motor pitch angle, a motor resistance value, a single-motor phase inductance and a pan-tilt movement speed; calculating to obtain phase current sine wave angular frequency of the motor by utilizing the transmission ratio of the holder, the motor pitch angle and the holder movement speed; and calculating to obtain impedance by using the phase current sine wave angular frequency, the motor resistance value and the single-motor phase inductance.
Wherein, the step of judging whether the cloud platform is out of step through the single-phase current of the motor of cloud platform includes: acquiring real-time single-phase currents of the motor in a static state through an analog-digital converter; calculating a second theoretical synthetic current through the square value of each single-phase current; acquiring third data of the motor, and calculating to obtain theoretical single-phase currents in a static state by using the third data and the second theoretical synthetic current; and comparing the difference value between any one single-phase current and the corresponding theoretical single-phase current with a second preset threshold value, and judging whether the cradle head is out of step.
The method comprises the following steps of obtaining third data of the motor, and calculating theoretical single-phase currents in a static state by using the third data, wherein the steps of: acquiring the current micro-step number and the maximum detail value of the motor; and calculating to obtain each theoretical single-phase current in the static state by using the current micro-step number, the maximum fraction value and the second theoretical composite current.
Wherein the step of performing the step-out correction comprises: the holder is in a static state; and acquiring a correct optical coupler position by using an optical coupler self-checking function of the holder so as to correct the step-out position.
Wherein, the step of utilizing the opto-coupler self-checking function of cloud platform to acquire correct opto-coupler position in order to carry out the correction of out-of-step position includes: when the out-of-step position is corrected by utilizing an optocoupler self-checking function of the holder, a user instruction is received and cached; when the cached user instruction is empty after the step-out position correction is finished, controlling the cradle head to return to the position in the static state; and when the step-out position correction is finished and the cached user instruction is not empty, controlling the movement of the holder according to the user instruction which is received recently in the cached user instruction.
In order to solve the above technical problem, the present invention further provides a control circuit of a pan/tilt head, wherein the control circuit of the pan/tilt head comprises: the processor is used for executing the control method of the tripod head according to any one of the above technical solutions.
In order to solve the above technical problem, the present invention also provides a computer-readable storage medium storing program data, which can be executed to implement the control method of the pan/tilt head according to any one of the above technical solutions.
The invention has the beneficial effects that: different from the prior art, the method provided by the invention has the advantages that the motion state of the cradle head is obtained firstly, and then the out-of-step condition of the cradle head is judged according to the different motion states of the cradle head and the synthetic current of the motor and the single-phase current of the motor respectively, so that the detection method has a certain degree of pertinence, and the detection process is simple and effective. The invention improves the accuracy and the real-time performance of the step-out detection.
Drawings
Fig. 1 is a schematic flow chart of an embodiment of a method for controlling a pan/tilt head according to the present invention;
fig. 2 is a schematic flow chart of another embodiment of the control method of the pan/tilt head provided by the invention;
FIG. 3 is a schematic structural diagram of a motor driving model in the embodiment of FIG. 2;
fig. 4 is a schematic flow chart of a control method of a pan/tilt head according to another embodiment of the present invention;
fig. 5 is a schematic structural diagram of an embodiment of a control circuit of a pan/tilt head provided by the present invention;
FIG. 6 is a schematic structural diagram of an embodiment of a computer-readable storage medium provided in the present invention.
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, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic flow chart of a method for controlling a pan/tilt head according to an embodiment of the present invention.
S11: and acquiring the motion state of the holder, and judging whether the motion state is a static state.
The current motion state of the holder is further obtained by obtaining the current speed and position of the holder, and whether the current motion state of the holder is a static state or not is judged.
When the holder is in a static state or a moving state, parameters such as back electromotive force, current waveform and the like of a holder motor have difference to a certain degree. Therefore, in this embodiment, different methods are respectively adopted to determine whether the pan/tilt is out of step according to different motion states of the pan/tilt.
S12: and if the motion state is not the static state, judging whether the cradle head is out of step through the synthetic current of a motor of the cradle head, and if the motion state is the static state, judging whether the cradle head is out of step through the single-phase current of the motor.
When the motion state of the pan/tilt head is judged not to be a static state, namely, the motion speed of the pan/tilt head is not zero, and the position of the pan/tilt head also changes. Comparing a square value of a current synthetic current between each single-phase current of a motor of the tripod head with a square value of a theoretical synthetic current of the motor (the theoretical synthetic current refers to a theoretical maximum current value corresponding to the normal motion of the tripod head at the current speed), wherein when a difference value between the square value of the current synthetic current and the square value of the theoretical synthetic current exceeds a first preset threshold value, the tripod head is in a step-out state; and when the difference value between the square value of the current synthetic current and the square value of the theoretical synthetic current does not exceed a first preset threshold value, the holder is in a normal state. The first preset threshold may be set according to actual application.
When the motion state of the tripod head is judged to be a static state, namely the speed of the tripod head is zero and the position is unchanged, comparing the current any one single-phase current of the motor with the theoretical single-phase current corresponding to the single phase (the theoretical single-phase current refers to the theoretical current value corresponding to each single phase when the tripod head normally moves at the current position), and when the difference value between the current single-phase current and the corresponding theoretical single-phase current exceeds a second preset threshold value, the tripod head is in a step-out state; when the difference value between the current single-phase current and the theoretical single-phase current corresponding to the single phase does not exceed a second preset threshold value, the holder is in a normal state. The second preset threshold value may be determined in advance by manually pulling the pan-tilt to cause the pan-tilt to be out of step and recording an average value of the current fluctuation amount, or by directly selecting a percentage of the maximum current.
S13: and if the cradle head is out of step, performing out-of-step correction.
And after the tripod head is judged to be in the out-of-step state, the tripod head is subjected to out-of-step correction through an optical coupler arranged on the tripod head. When having the opto-coupler to carry out the step-out through the cloud platform and proofreaying and correct, the cloud platform can not restart and only carry out the step-out through the internally triggered opto-coupler self-checking module and proofreaies and correct. The purpose of performing the out-of-step correction without restarting the cradle head is to enable the cradle head to receive and cache a user instruction issued by a user in the correction process in the out-of-step correction process, so that the phenomenon that the control failure of the cradle head is influenced by the user due to the fact that the user instruction is lost due to the restart of the cradle head in the correction process is prevented, and the influence on user experience is avoided.
Through the mode, the tripod head control method judges the out-of-step condition of the tripod head through the synthetic current of the motor and the single-phase current of the motor respectively according to different motion states of the tripod head, and the detection method has certain pertinence, so that the detection process is simple and effective, and the accuracy and the real-time performance of out-of-step detection are improved. And under the condition that other devices are not added, the invention only carries out the step-out correction through the existing optocoupler in the holder, so that the holder can carry out the step-out correction under the condition of not restarting, the phenomenon that the user instruction is lost due to restarting of the holder is reduced, and the expenditure of the holder detection cost is indirectly saved.
Referring to fig. 2, fig. 2 is a schematic flow chart of another embodiment of a pan/tilt head control method according to the present invention. The present embodiment will explain detection of step-out and recovery of step-out of a pan/tilt head in a moving state. In this embodiment, the pan/tilt motor is a two-phase stepping motor. In practical application, the type of the motor can be selected according to practical situations.
S21: and acquiring the motion state of the holder, and judging that the motion state is not a static state.
The current motion state of the holder is further obtained by obtaining the current speed and position of the holder, and whether the current motion state of the holder is a static state or not is judged.
And when the current movement speed of the holder is judged to be not zero, the position of the holder is changed. Then, at this time, the pan/tilt head is not in a stationary state, i.e., the pan/tilt head is in a moving state. Wherein the pan-tilt camera is usually rotated in a horizontal direction and/or a vertical direction, respectively, when it is in motion. In this embodiment, the step-out detection will be described by taking the horizontal movement of the pan/tilt head as an example, and the vertical movement will be the same.
S22: and acquiring first data, and calculating phase current sine wave angular frequency and impedance of the motor based on the first data.
Acquiring current first data of a holder, wherein the first data comprises: transmission ratio n of cradle headConveying applianceResistance R of motor, and pitch angle theta of motorPitch of teethAnd horizontal movement velocity V of the pan/tilt head. According to the transmission ratio n of the pan-tiltConveying applianceMotor pitch angle thetaPitch of teethAnd calculating the horizontal movement speed V of the holder to obtain the phase current sine wave angular frequency w of the motor, wherein the specific calculation formula is as follows:
w＝2πf＝2πVnconveying appliance/θPitch of teeth(1)
Wherein, the transmission ratio n of the holderConveying applianceThe transmission ratio of the cradle head transmission chain, namely the degree n of the motor which theoretically needs to rotate when the cradle head rotates by 1 degreeConveying appliance(ii) a Motor pitch angle thetaPitch of teethIs the pitch angle of the tripod head motor; f is the winding sine wave frequency of the motor; the horizontal pan/tilt movement velocity V is a movement velocity in the horizontal direction of the pan/tilt. When the holder moves in the vertical direction, the moving speed V in the horizontal direction of the holder in this step is replaced with the moving speed in the vertical direction of the holder.
After the phase current sine wave angular frequency w of the motor is obtained, the impedance Z of the motor is further calculated by using the resistance R of the motor and the phase inductance L of the single motor, and the specific formula is as follows:
the motor resistance value R is the sum of a motor phase resistor and a drive circuit H bridge conduction resistor; the single-motor phase inductance L is the phase inductance of a single motor winding.
S23: the driving voltage of the motor is obtained, second data of the motor is obtained based on a driving model of the motor, and a first theoretical synthetic current is obtained through calculation of the driving voltage, the phase current sine wave angular frequency, the second data and impedance.
And obtaining a driving voltage U of the motor, obtaining second data of the motor by using a driving model of the motor based on the driving voltage U, and calculating to obtain a first theoretical synthetic current by using the driving voltage U, the second data, the impedance Z obtained in the previous step and the phase current sine wave angular frequency w. Wherein the second data comprises: drive voltage U, load angle gamma and phase lag angle of motor
The back emf constant | C | and the angle β related to the impedance.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a motor driving model in the present embodiment.
The motor model 10 of the present embodiment includes: power supply 01, ground 02, and motor winding 05. Wherein the motor winding 05 comprises: inductor 03 and resistor 04.
Specifically, the power supply 01 generates a driving voltage U, the inductance of the inductor 03 is a single-motor phase inductor L, the resistance of the resistor 04 is a motor resistance R, the current passing through the motor model 10 is I, and a back electromotive force C is generated in the motor winding 05.
The following formula can be obtained by the motor driving model of the embodiment:
U＝I·(R+jwL)+wC (3)
wherein U, I, and C are vectors, and formula (3) is expressed by polar coordinates:
wherein gamma is a load angle for reflecting the relationship of the included angle between the rotor magnetic field and the stator magnetic field, and the load angle gamma is a given reference value (the load angle gamma is between 0 and 90 degrees and can be measured after the motor normally moves at a certain fixed speed). U shapemIs the peak value of the sine wave drive voltage, ImIs a sine wave current peak value, i.e. a first theoretical resultant current value，
I.e., the phase lag angle (i.e., the angle of the current lag voltage) | Z | is the impedance magnitude, β is the angle related to the impedance, | C | is the back emf constant, which can be obtained through practical measurement.
Both sides of equation (4) are reduced by e (jwt):
taking the phase of the motor driving voltage U as a reference, that is, making θ equal to 0, we can obtain:
the modulus I of the maximum first theoretical composite current obtained by the formula (6) in a geometric vector methodmI is:
s24: and acquiring real-time single-phase currents of the motor in the motion state through the analog-digital converter, and summing square values of the single-phase currents to obtain a real-time square value of a synthesized current of the motor in the motion state.
The analog-to-digital converter (ADC) is used to collect the current values I of the two phases of the two-phase motor A, B during the interruption of the pan-tilt timer (minimum movement period)AAnd IB。
Summing the square values of the single-phase currents to obtain the square value of the synthesized current of the motor in the current motion state, wherein the specific formula is as follows:
wherein, IP is combinedThe current is the real-time synthesized current under the motor motion state.
S25: and comparing the difference value between the square value of the synthetic current and the square value of the first theoretical synthetic current with a first preset threshold value to judge whether the holder is out of step.
By combining the present resultant current IP is combinedThe square value of (d) and the first theoretical resultant current ImIs compared with a first predetermined threshold FExercise of sportsAnd comparing to judge whether the cradle head is out of step.
When I is2 P is combined-I2 m>FExercise of sportsWhen, i.e. the resultant current IP is combinedThe square value of (d) and the first theoretical resultant current ImExceeds a first predetermined threshold FExercise of sportsThen the cradle head can be judged to be in the out-of-step state currently. Otherwise, the holder is in a normal motion state.
In this step, the modulus | I of the first theoretical composite current can be obtained through the formula (7) by obtaining the driving voltage U, the load angle γ and the driving voltage angular frequency w set by the motor and knowing the motor resistance R, the single-motor phase inductance L and the back electromotive force constant | C | of the motorm|。
In the process that the motor runs at the speed of w, when step loss occurs, the actual load angle gamma is increased to be more than 90 degrees, and according to the formula (7), the maximum value of the actual current is larger than that of the current in normal motion when step loss occurs, so that the collected combined current IP is combinedWill be compared with the first theoretical resultant current I at that speedmTherefore, the step-out can be quickly judged by comparing the synthesized current.
S26: and the cradle head is in a static state, and the correct optical coupler position is acquired by using the optical coupler self-checking function of the cradle head so as to correct the step-out position.
A Flag (a cradle head internal Flag) when the cradle head is in the out-of-step state is set. The flag can be set according to practical application, for example: when the tripod head is out of step, a mark 1 appears inside the tripod head.
When the tripod head is detected to be in the out-of-step state, the tripod head out-of-step mark Flag appears. After the tripod head receives the mark, the tripod head in the motion state is stopped to keep the tripod head in the static state, and then the coordinate value P of the tripod head at the stop position is recorded. And under the condition that the cradle head is not restarted, the accurate optocoupler position is found only by an optocoupler self-checking function of the internal trigger cradle head to correct the out-of-step position. And receiving and caching a user instruction while the tripod head performs out-of-step position correction. After the correction is finished, if the cached user instruction is null, returning the cradle head to the position P according to the coordinate value P; and if the cached user instruction is not empty, controlling the holder to move according to the user instruction which is received recently in the cached user instruction. At this time, the step-out correction is completed, and the cradle head normally executes the motion command subsequently issued to the cradle head.
Through the mode, whether the tripod head is out of step in the moving state can be judged only by comparing the difference value between the square value of the synthetic current and the square value of the first theoretical synthetic current with the first preset threshold value once in each minimum moving period, and the accuracy and the real-time performance of the detection of the out of step of the tripod head are improved. The calculation method reduces the calculation amount in the out-of-step processing process, so that the out-of-step judgment process is simple and effective, and the out-of-step detection efficiency is improved. Meanwhile, the step-out recovery of the invention obtains the correct optical coupler position through the optical coupler self-checking function of the holder so as to correct the step-out position.
Referring to fig. 4, fig. 4 is a schematic flow chart of a cradle head control method according to another embodiment of the present invention. The present embodiment will explain detection of loss of synchronism and recovery of loss of synchronism of the pan/tilt head in a stationary state. In this embodiment, the pan/tilt motor is a two-phase stepping motor, and in practical application, the motor can be selected according to practical situations.
S31: and acquiring the motion state of the holder, and judging that the motion state is a static state.
The current motion state of the holder is further obtained by obtaining the current speed and position of the holder, and whether the current motion state of the holder is a static state or not is judged. Wherein, the motion state of cloud platform includes: motion and stationary.
And when the current movement speed of the holder is judged to be zero, the position of the holder is not changed. Then the pan/tilt head is at rest.
Because the parameters such as the back electromotive force and the current waveform of the motor of the holder have differences to a certain extent when the holder is in a static state or a moving state, in this embodiment, different methods are respectively adopted to judge whether the holder is out of step according to different moving states of the holder.
When the pan-tilt head is in a static state, namely the phase current sine wave angular frequency w of the motor is zero, the phase current sine wave angular frequency w is substituted into the formula (7), and the calculated | Im|＝|Umi/Z is a fixed value, that is, the first theoretical synthesized current value obtained by the method of summing squares is invariable (whether the tripod head is out of step or not, whether the tripod head is manually pulled or not, and the current amplitude synthesized by each phase winding is invariable), so that whether the tripod head is out of step or not cannot be judged by the synthesized current of the motor.
S32: and acquiring real-time single-phase currents of the motor in a static state through the analog-digital converter.
The method includes the steps of directly acquiring the magnitude I of the current a-phase current and the current b-phase current of a two-phase motor through an analog-digital convertera' or/and Ib′。
S33: and calculating a second theoretical composite current through the square value of each single-phase current.
When the holder is in a moving state, each phase of current is changed according to a sine wave with a certain frequency; when the holder is in a static state, the current of each phase is always kept at a certain time point of the sine wave, and the corresponding current value is kept constant. In order to ensure the control effect, the stepping motor of this embodiment generally adopts a subdivision control, the subdivision-controlled stepping motor can divide a step angle (e.g. 0.9 degree) into 256 micro steps, and then can stop at any position of one of the micro steps by controlling two-phase currents, that is, the transient value of each phase current at the same stationary time can fall at any point on a sine wave, and the composite current value of each phase current is fixed, so that the second theoretical composite current can be obtained by measuring each single-phase current at a certain actual time.
The square value of the second theoretical composite current is obtained by adding the square values of the single-phase currents, and the second theoretical composite current I is further obtainedm'. The formula is as follows:
Im ′2＝Ia ′2+Ib ′2(9)
wherein the second theoretical synthesized current Im' can also be calculated by equation (7) of the previous embodiment, but this approach is more complicated than equation (9).
S34: and acquiring third data of the motor, and calculating to obtain each theoretical single-phase current in the static state by using the third data and the second theoretical composite current.
Obtaining the current micro-step number N of the motorStep by stepWith the maximum value of detail Nmax subdivisionAnd using the current micro-step number NStep by stepMaximum fine value Nmax subdivisionAnd a second theoretical resultant current Im' calculation to obtain each theoretical single-phase current I under static stateaAnd IbThe concrete formula is as follows:
wherein N ismax subdivisionIf the maximum fraction value is 256, for example, it indicates that 1024 micro-steps are needed when the motor current has updated one sine wave. N is a radical ofStep by stepRepresenting the specific position of the stationary moment in the sine wave for the corresponding current micro-step number in the stationary moment, wherein the value is 0-4 xNmax subdivisionTo change between.
S35: and comparing the difference value between any one single-phase current and the corresponding theoretical single-phase current with a second preset threshold value, and judging whether the cradle head is out of step.
The difference value between any single-phase current and the corresponding theoretical single-phase current is compared with a second preset threshold value FAt restAnd (3) comparing, judging whether the cradle head is out of step or not, taking the phase a current as an example:
when Ia′-Ia|>FAt restAnd (3) when the phase-a current is in a step-out state, namely the difference value between the phase-a current and the theoretical phase-a current exceeds a second preset threshold value, the cradle head is in a step-out state. Wherein the second preset threshold value FAt restThe current fluctuation amount can be determined in advance by manually pulling the holder to be out of step and recording the average value of the current fluctuation amount, or directly selecting the percentage of the maximum current. Otherwise, the holder is in a normal state.
S36: and acquiring a correct optical coupler position by using an optical coupler self-checking function of the holder so as to correct the step-out position.
A Flag (a cradle head internal Flag) when the cradle head is in the out-of-step state is set. The flag can be set according to practical application, for example: when the tripod head is out of step, a mark 1 appears inside the tripod head. When the Flag appears inside the pan/tilt head, the coordinate P' of the pan/tilt head in the static state at this time is recorded. And under the condition that the cradle head is not restarted, the accurate optocoupler position is found only by an optocoupler self-checking function of the internal trigger cradle head to correct the out-of-step position. And receiving and caching a user instruction while the tripod head performs out-of-step position correction. After the correction is finished, if the cached user instruction is null, the cradle head is returned to the position P 'according to the coordinate value P'; and if the cached user instruction is not empty, controlling the holder to move according to the user instruction which is received recently in the cached user instruction. At this time, the step-out correction is completed, and the cradle head normally executes the motion command subsequently issued to the cradle head.
Through the mode, the method can directly compare the difference value between each real-time single-phase current value and each theoretical single-phase current value with the second preset threshold value, so that whether the tripod head is out of step in a static state can be judged, and the accuracy and the real-time performance of the detection of the out-of-step of the tripod head are improved. The calculation method reduces the calculation amount in the out-of-step processing process, so that the out-of-step judgment process is simple and effective, and the out-of-step detection efficiency is improved. Meanwhile, the step-out recovery of the invention obtains the correct optical coupler position through the optical coupler self-checking function of the holder so as to correct the step-out position. Through the correction mode, the invention can receive and buffer the user command while finishing the step-out correction on the premise of not restarting the cradle head, thereby reducing the loss of the user command caused by restarting and ensuring that the cradle head has more accurate control effect.
Based on the same inventive concept, the present invention further provides a control circuit of a pan/tilt head, where the control circuit of the pan/tilt head can be executed to implement the control method of the pan/tilt head according to any of the above embodiments, please refer to fig. 5, where fig. 5 is a schematic structural diagram of an embodiment of the control circuit of the pan/tilt head provided by the present invention, and the control circuit of the pan/tilt head includes a processor 41 and a memory 42.
Wherein the memory 42 is adapted to store the real time resultant current, the first theoretical resultant current, the real time individual phase currents and the theoretical individual phase currents of the motor.
The processor 41 is configured to further obtain a current motion state of the pan/tilt head by obtaining a current speed and a current position of the pan/tilt head, and determine whether the current motion state of the pan/tilt head is a static state.
When the cradle head is not in the static state, the processor 41 is configured to obtain current first data of the cradle head, where the first data includes: transmission ratio n of cradle headConveying applianceMotor resistance R, drive voltage U, motor pitch angle thetaPitch of teethAnd horizontal movement velocity V of the pan/tilt head. According to the transmission ratio n of the pan-tiltConveying applianceMotor pitch angle thetaPitch of teethAnd calculating the horizontal movement speed V of the holder to obtain the phase current sine wave angular frequency w of the motor, and further calculating to obtain the impedance Z of the motor. The processor 41 is further configured to obtain a driving voltage U of the motor, obtain second data of the motor by using a driving model of the motor based on the driving voltage U, and calculate to obtain a first theoretical synthesized current I by using the driving voltage U, the second data, the impedance Z obtained in the previous step, and the phase current sine wave angular frequency wm. By combining the currents I in real timeP is combinedThe square value of (d) and the first theoretical resultant current ImIs compared with a first predetermined threshold FExercise of sportsAnd comparing to judge whether the cradle head is out of step. When the cradle head is judged to be out of step, the processor 41 receives the out-of-step mark, stops the cradle head in the moving state, keeps the cradle head in the static state, and records the coordinate value P when the cradle head is at the stop position. The cradle head is not restarted, and the accurate optocoupler position is found only through an optocoupler self-checking function of the internal trigger cradle head to carry out step-out position correction. And receiving and caching a user instruction while the tripod head performs out-of-step position correction. After the correction is finished, if the cached user instruction is null, returning the cradle head to the position P according to the coordinate value P; and if the cached user instruction is not empty, controlling the holder to move according to the latest user instruction. At this time, the step-out correction is completed, and the cradle head normally executes the motion command subsequently issued to the cradle head.
When the cradle head is determined to be in the static state, the processor 41 is configured to obtain third data of the motor, where the third data includes: current number of microsteps NStep by stepWith the maximum value of detail Nmax subdivisionAnd using the current micro-step number NStep by stepMaximum fine value Nmax subdivisionAnd a second theoretical resultant current Im' calculation to obtain each theoretical single-phase current I under static stateaAnd Ib. The processor 41 is further configured to directly acquire the magnitude I of the current a-phase current and the current b-phase current of the two-phase motor through the analog-to-digital convertera' or/and Ib'. The difference value between any single-phase current and the corresponding theoretical single-phase current is compared with a second preset threshold value FAt restAnd comparing to judge whether the cradle head is out of step. For example: if phase a current Ia' AND theory a phase Current IaThe difference between them exceeds a second predetermined threshold value FAt restAnd the cradle head is in the out-of-step state. If phase a current Ia' AND theory a phase Current IaThe difference between them does not exceed the second preset threshold FAt restAnd the cradle head is in a normal state. When the cradle head is judged to be out of step, the processor 41 receives the out-of-step mark and records the coordinate value P' of the cradle head in the static state at the moment. The cradle head is not restarted, and the accurate optocoupler position is found only through an optocoupler self-checking function of the internal trigger cradle head to carry out step-out position correction. And the same step-out position correction is carried out on the cradle headAnd receiving and caching the user instruction. After the correction is finished, if the cached user instruction is empty, returning the cradle head to the position P 'according to the coordinate value P'; and if the cached user instruction is not empty, controlling the holder to move according to the user instruction which is received recently in the cached user instruction. At this time, the step-out correction is completed, and the cradle head normally executes the motion command subsequently issued to the cradle head.
By the mode, according to different motion states of the tripod head, when the tripod head is in the motion state, whether the tripod head is out of step in the motion state can be judged only by comparing the difference value between the square value of the synthetic current and the square value of the first theoretical synthetic current with the first preset threshold value once in each minimum motion period; when the holder is in a static state, directly comparing the difference value between each real-time single-phase current value and each theoretical single-phase current value with a second preset threshold value to judge whether the holder is out of step or not in the static state; the accuracy and the real-time performance of the detection of the step-out of the holder are improved. The calculation method reduces the calculation amount in the out-of-step processing process, so that the out-of-step judgment process is simple and effective, and the out-of-step detection efficiency is improved. Meanwhile, the step-out recovery of the invention obtains the correct optical coupler position through the optical coupler self-checking function of the holder so as to correct the step-out position. Through the correction mode, the invention can receive and buffer the user command while finishing the step-out correction on the premise of not restarting the cradle head, thereby reducing the loss of the user command caused by restarting and ensuring that the cradle head has more accurate control effect. And indirectly saves the expenditure of the detection cost of the holder.
Based on the same inventive concept, the present invention further provides a computer-readable storage medium, please refer to fig. 6, and fig. 6 is a schematic structural diagram of an embodiment of the computer-readable storage medium provided in the present invention. The computer-readable storage medium 50 has stored therein at least one program data 51, the program data 51 being adapted to implement any of the methods described above. In one embodiment, the computer-readable storage medium 50 includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
On one hand, the invention separates the instruction cache and the data cache physically, and the physical separation structure improves the data acquisition efficiency and reduces the manufacturing complexity of the microprocessor. On the other hand, the instruction cache and the data cache are logically combined, which is equivalent to enlarging the capacity of the first-level cache, thereby improving the cache hit rate.
In the embodiments provided in the present invention, it should be understood that the disclosed method and apparatus can be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, a division of a module or a unit is merely a logical division, and an actual implementation may have another division, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
Units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on this understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium, or in a part of or all of the technical solution that contributes to the prior art.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A control method of a pan/tilt head is characterized by comprising the following steps:
acquiring the motion state of the holder, and judging whether the motion state is a static state;
if the motion state is not the static state, judging whether the cradle head is out of step or not through the synthetic current of a motor of the cradle head, and if the motion state is the static state, judging whether the cradle head is out of step or not through the single-phase current of the motor;
and if the cradle head is out of step, performing out-of-step correction.
2. A method for controlling a head according to claim 1, wherein said step of determining whether said head is out of step by means of a resulting current of a motor of said head comprises:
acquiring first data of the holder, and calculating to obtain a first theoretical synthetic current of the motor based on the first data;
acquiring real-time single-phase currents of the motor in a motion state through an analog-digital converter;
summing the square values of the single-phase currents to obtain the real-time square value of the synthesized current in the motor motion state;
and comparing the difference value between the square value of the synthetic current and the square value of the first theoretical synthetic current with a first preset threshold value to judge whether the cradle head is out of step.
3. A method for controlling a head according to claim 2, wherein said step of acquiring first data of said head and calculating a first theoretical resultant current of said motor on the basis of said first data comprises:
acquiring the first data, and calculating phase current sine wave angular frequency and impedance of the motor based on the first data;
acquiring a driving voltage of the motor, and acquiring second data of the motor based on a driving model of the motor; wherein the second data comprises: a load angle, a phase lag angle, a back electromotive force constant, and an angle related to the impedance of the motor;
and calculating the first theoretical composite current by using the driving voltage, the phase current sine wave angular frequency, the second data and the impedance.
4. A method according to claim 3, wherein said step of obtaining said first data and calculating phase current sine wave angular frequency and impedance of said motor based on said first data comprises:
acquiring a pan-tilt transmission ratio, a motor pitch angle, a motor resistance value, a single-motor phase inductance and a pan-tilt movement speed;
calculating to obtain phase current sine wave angular frequency of the motor by utilizing the transmission ratio of the holder, the motor pitch angle and the holder movement speed;
and calculating to obtain the impedance by utilizing the phase current sine wave angular frequency, the motor resistance value and the single-motor phase inductance.
5. A method for controlling a head according to claim 1, wherein said step of determining whether said head is out of step by means of a single-phase current of a motor of said head comprises:
acquiring real-time single-phase currents of the motor in a static state through an analog-digital converter;
calculating a second theoretical synthetic current according to the square value of each single-phase current;
acquiring third data of the motor, and calculating to obtain theoretical single-phase currents in a static state by using the third data and the second theoretical composite current;
and comparing the difference value between any one single-phase current and the corresponding theoretical single-phase current with a second preset threshold value, and judging whether the cradle head is out of step.
6. A control method of a pan and tilt head according to claim 5, wherein said step of obtaining third data of said motor and calculating each theoretical single-phase current at rest using said third data comprises:
acquiring the current micro-step number and the maximum fine-step value of the motor;
and calculating to obtain each theoretical single-phase current in the static state by using the current micro-step number, the maximum fraction value and the second theoretical composite current.
7. A control method of a head according to claim 1, wherein said step of performing an out-of-step correction comprises:
bringing the head to the stationary state;
and acquiring a correct optical coupler position by using an optical coupler self-checking function of the holder so as to correct the step-out position.
8. A control method of a pan and tilt head according to claim 7, wherein said step of obtaining the correct opto-coupler position for out-of-step position correction by using the opto-coupler self-checking function of said pan and tilt head comprises:
when the out-of-step position correction is carried out by utilizing the optical coupling self-checking function of the holder, a user instruction is received and cached;
when the out-of-step position correction is finished and the cached user instruction is empty, controlling the cradle head to return to the position of the static state;
and when the out-of-step position correction is finished and the cached user instruction is not empty, controlling the movement of the holder according to the user instruction which is received recently in the cached user instruction.
9. A control circuit of a pan/tilt head, the control circuit comprising: a processor and a memory, said memory storing the resultant current and the single-phase current of the motor, said processor being adapted to execute the method of controlling a head according to any one of claims 1 to 8.
10. A computer-readable storage medium, characterized in that it stores program data executable to implement a control method of a head according to any one of claims 1 to 8.
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| CN1404214A (en) * | 2001-09-03 | 2003-03-19 | 三菱电机株式会社 | Step failing out detecting apparatus and method for synchronous motor, driving apparatus for motor |
| EP2023223A1 (en) * | 2007-07-24 | 2009-02-11 | Honeywell International Inc. | Apparatus and method for determining a camera's required motor holding current |
| CN101710692A (en) * | 2009-09-15 | 2010-05-19 | 珠海瑞捷电气有限公司 | Out-of-step protection method for synchronous motor |
| CN101884162A (en) * | 2007-12-03 | 2010-11-10 | 霍夫曼-拉罗奇有限公司 | Be used to discern the method and apparatus of stepping motor step-out |
| CN104038686A (en) * | 2013-03-05 | 2014-09-10 | 株式会社日立制作所 | Imaging Device, Motor Driving Device And Imaging Method |
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2020
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|---|---|---|---|---|
| CN1404214A (en) * | 2001-09-03 | 2003-03-19 | 三菱电机株式会社 | Step failing out detecting apparatus and method for synchronous motor, driving apparatus for motor |
| EP2023223A1 (en) * | 2007-07-24 | 2009-02-11 | Honeywell International Inc. | Apparatus and method for determining a camera's required motor holding current |
| CN101884162A (en) * | 2007-12-03 | 2010-11-10 | 霍夫曼-拉罗奇有限公司 | Be used to discern the method and apparatus of stepping motor step-out |
| CN101710692A (en) * | 2009-09-15 | 2010-05-19 | 珠海瑞捷电气有限公司 | Out-of-step protection method for synchronous motor |
| CN104038686A (en) * | 2013-03-05 | 2014-09-10 | 株式会社日立制作所 | Imaging Device, Motor Driving Device And Imaging Method |
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