CN111630772B - Servo system mechanical parameter identification method, servo control system and storage device - Google Patents
Servo system mechanical parameter identification method, servo control system and storage device Download PDFInfo
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- CN111630772B CN111630772B CN201880087339.6A CN201880087339A CN111630772B CN 111630772 B CN111630772 B CN 111630772B CN 201880087339 A CN201880087339 A CN 201880087339A CN 111630772 B CN111630772 B CN 111630772B
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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
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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
- H02P21/20—Estimation of torque
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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
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/14—Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
Abstract
The invention discloses a servo system mechanical parameter identification method, a servo control system and a storage device. The method comprises the following steps: the angular acceleration of the servo motor is changed for a plurality of times; collecting current information, angular velocity information and angular position information of the servo motor at a plurality of different moments; acquiring a plurality of groups of angular position change values, angular speed change values and accumulated torque impulse values with preset sampling lengths according to the angular position information, the angular speed information and the current information of the servo motor; fitting a mechanical characteristic plane of the servo motor according to the angular position change value, the angular speed change value and the accumulated torque impulse value; and acquiring the mechanical parameters of the servo system according to the mechanical characteristic plane.
Description
Technical Field
The present invention relates to the field of servo systems, and in particular, to a method for identifying mechanical parameters of a servo system, a servo control system, and a storage device.
Background
In the control process of the servo system, the identification of the mechanical parameters of the servo system is very important, and only the mechanical parameters of the servo system are obtained, the control parameters of the servo system can be accurately adjusted, so that the purpose of accurate control is realized. The mechanical parameters of the servo system comprise rotational inertia, viscous friction coefficient, dynamic friction coefficient, unbalanced load weight torque and the like.
The traditional servo system mechanical parameter identification method adopts a model reference self-adaptive identification method, and is to compare a variable model for changing the load moment of inertia with an actual motor model until the variable model and the actual motor model reach the same output, and then the identification is considered to be completed. However, setting parameters in the variable model is difficult, such as setting the improperly identified process may not be complete or take a lot of time, and typically only the moment of inertia of the servo system can be identified, and other parameters may not be identified. Therefore, a new method for identifying mechanical parameters of a servo system is needed.
Disclosure of Invention
The invention provides a servo system mechanical parameter identification method, a servo control system and a storage device.
In order to solve the technical problems, the invention provides a technical scheme that: a method for identifying mechanical parameters of a servo system is provided, which comprises the following steps: the angular acceleration of the servo motor is changed for a plurality of times; collecting current information, angular velocity information and angular position information of the servo motor at a plurality of different moments; acquiring a plurality of groups of angular position change values, angular speed change values and accumulated torque impulse values under a preset sampling length according to the angular position information, the angular speed information and the current information of the servo motor; fitting a mechanical characteristic plane of the servo motor according to the angular position change value, the angular speed change value and the accumulated torque impulse value; and acquiring the mechanical parameters of the servo system according to the mechanical characteristic plane.
In order to solve the technical problems, the invention provides another technical scheme as follows: a servo control system is provided, comprising a processor, wherein the processor can load program instructions and execute the servo system mechanical parameter identification method.
In order to solve the technical problems, the invention provides another technical scheme as follows: an apparatus having a memory function is provided, in which program instructions are stored, which can be loaded and executed by the aforementioned servo system mechanical parameter identification method.
The beneficial effects of the invention are as follows: by collecting current information, angular velocity information and angular position information of the servo motor at different moments and utilizing the information to obtain a plurality of groups of angular velocity changes, angle changes and accumulated torque impulses of the servo motor, the mechanical characteristic plane of the servo motor can be fitted, and a plurality of mechanical parameters of the servo motor can be determined according to the mechanical characteristic plane of the servo motor. In addition, since the calculation is performed using a plurality of sub-time periods instead of each sampling timing, the influence of the system delay and the system noise on the calculation result can be reduced. Therefore, the invention can effectively and accurately identify the mechanical parameters of the servo system.
Drawings
FIG. 1 is a flowchart illustrating an embodiment of a method for identifying mechanical parameters of a servo system according to the present invention.
FIG. 2 is a flowchart illustrating a method for identifying mechanical parameters of a servo system according to another embodiment of the present invention.
FIG. 3 is a flow chart illustrating a method of acquiring a mechanical property plane of a servo motor and determining a mechanical parameter of a servo system based on a parameter of the mechanical property plane, according to one embodiment of the present invention.
FIG. 4 is a flow chart of an algorithm for implementing the method for identifying mechanical parameters of a servo system according to the present invention.
FIG. 5 is a schematic diagram of a servo control system according to an embodiment of the present invention.
FIG. 6 is a schematic diagram showing a fitted mechanical property plane of a servo system according to an embodiment of the present invention.
Fig. 7 shows a schematic representation of the intersection of the plane of mechanical properties fitted in fig. 6 with a first plane defined by the angular velocity variation and the cumulative torque coordinate axis.
Fig. 8 shows a schematic representation of the intersection of the mechanical property plane fitted in fig. 6 with a second plane defined by the angular position change and the cumulative torque coordinate axis.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The mechanical equations of motion for a typical servomotor are as follows:
wherein T is e Representing the torque of the motor, T f Represents kinetic friction moment, T G Representing the unbalanced load moment, J represents the sum of the moment of inertia of the servo motor and the moment of inertia of the load translated to the motor shaft, and B represents the viscous coefficient of friction. The present invention proposes a method for identifying the mechanical parameters in the above equation.
Referring to fig. 1, fig. 1 is a flowchart illustrating an embodiment of a method for identifying mechanical parameters of a servo system according to the present invention. The method comprises the following steps:
s101: the angular acceleration of the servo motor is changed a plurality of times.
In step S101, the angular acceleration of the servo motor is changed a plurality of times to perform a test. The angular acceleration of the servo motor may be varied by providing a corresponding set of position, velocity or current loops in the servo control loop. By changing the angular acceleration of the servo motor a plurality of times, the servo motor can be operated at different angular speeds and reach a plurality of different angular positions during the operation of the servo motor. It will be appreciated that the test procedure for making multiple changes to the angular acceleration of the servo motor may be performed only once. In order to improve the accuracy of identification and eliminate or reduce the influence of random errors, multiple tests can be performed, and the angular acceleration of the servo motor can be changed multiple times in each test process.
Alternatively, according to some embodiments, the angular position of the servo motor may be changed from zero to a specified angle by changing the angular acceleration and angular jerk (i.e., the derivative of the angular acceleration) of the servo motor during each test, and during this time the angular speed of the servo motor gradually increases from zero and finally gradually decreases to zero again. Therefore, the angle position change curve of the servo motor is S-shaped, the whole system can be started and stopped stably, and the impact on the connecting structure of the servo system is small.
S102: and collecting current information, angular velocity information and angular position information of the servo motor at a plurality of different moments.
In the running process of the servo motor, current information, angular velocity information and angular position information of the servo motor at a plurality of different moments are collected. Such information may be measured directly, for example by a current sensor. The information may also be calculated indirectly, for example by integrating the angular acceleration to obtain the angular velocity and integrating the angular velocity to obtain the angular position. Alternatively, the intervals of each acquisition may be uniform, for example, with a fixed sampling frequency, or the sampling frequency of the acquisition may be dynamically adjusted during operation of the servo motor.
S103: and acquiring a plurality of groups of angle position change values, angle speed change values and accumulated torque impulse values under the preset sampling length according to the angle position information, the angle speed information and the current information of the servo motor.
The preset sampling length may represent the number of sampling points, for example, if the preset sampling length is 10, it is explained that 10 sampling points are grouped and the change value of the angular position, the change value of the angular velocity and the accumulated torque impulse value of each group are calculated respectively. The change in angular position and the change in angular velocity of each set of sampling points may be calculated using the difference in angular position between the last point and the first point in each set of sampling points and the difference in angular velocity. In addition, since the torque of the servo motor is proportional to the current (Q-axis current), the torque value of each point in each set of sampling points can be calculated, and the accumulated torque impulse value of the servo motor in each time period can be obtained by integrating the time interval between each point. Therefore, according to the angular position information, the angular speed information and the current information of the servo motor, a plurality of groups of angular position change values, angular speed change values and accumulated torque impulse values under the preset sampling length can be obtained.
In some embodiments, the starting time and the sampling length may be preset so as to divide the data points acquired during the test into multiple groups. The starting time can be set to be the time when the servo motor starts to operate, for example, the time when the angular position of the servo motor is zero, or the starting time can be set to be the time when the servo motor starts to operate for a period of time in order to avoid disturbance during starting, at this time, the rotating speed of the servo motor is gradually increased, and the interference of the non-linear phenomenon of friction during low-speed rotation on the test is avoided. The sampling length may be the number of sampling points, the sampling length being at least equal to 2, i.e. a time period comprising at least two sampling data points. For example, if the angle of the sampling point at the starting time is k and the sampling length is set to m, the whole test process can be divided into a plurality of sub-time periods, and the angles of the sampling points included in each sub-time period are respectively k to k+m-1, k+m to k+2m-1, k+2m to k+3m-1, and the like, so that all the sampling points are included. The data obtained at the sampling points in each time period can be used to calculate a set of angular position change values, angular velocity change values, and accumulated torque impulse values in step S103.
In some embodiments, the sampling intervals between any adjacent two of the plurality of sets of angular position change values, angular velocity change values, and accumulated torque impulse values are uniform. The sampling interval may be preset, and when the whole test process is divided into a plurality of sub-time periods, the start time of each sub-time period may be determined according to the sampling interval, and the end time of each sub-time period may be determined according to the sampling length. For example, for the above example, the sampling interval n may be set, and then the angular labels of the sampling points included in each time period become k to k+m-1, k+n to k+n+m-1, k+2n to k+2n+m-1 … …, and in some embodiments, the sampling interval may be smaller than the sampling length, so that there may be an overlapping area between two adjacent time periods, so as to provide more groups of change values of the angular position, change values of the angular velocity, and accumulated torque impulse values for subsequent fitting, which helps to improve accuracy of subsequent fitting calculation.
S104: and fitting a mechanical characteristic plane of the servo motor according to the obtained multiple groups of angle position change values, angular velocity change values and accumulated torque impulse values.
The relationship between the angular position change value, the angular velocity change value, and the accumulated torque impulse value may reflect the mechanical characteristics of the servo system. Therefore, by fitting the plurality of sets of the angular position change value, the angular velocity change value, and the integrated torque impulse value obtained in step S103, the mechanical characteristic plane of the servo motor can be obtained. For example, in step S104, the change in the plurality of sets of angular position information, the change in the angular information, and the accumulated torque impulse value are defined as a plurality of coordinate points in space, with the angular velocity change, the angular position change, and the accumulated torque as coordinate axes, respectively. It can be seen from the combination of the mechanical motion equation of the servo system that the coordinate points obtained by the above definition should theoretically conform to the integrated equation of the mechanical motion equation of the servo system, i.e
Where ti and ti+1 represent the start and end times, respectively, of each sample length. Of course, due to various errors, the coordinate points do not completely fall on the plane defined by the equation, so that the coordinate points can be fitted, and the plane corresponding to the equation integrated by the mechanical motion equation of the servo system is obtained. The specific fitting method is not limited, and a fitting plane nearest to each coordinate point is found using, for example, a least square method.
It should be noted that in actual operation, step S105 may be performed in an actual image space, or may represent only arithmetic operations in a mathematical sense.
S105: the mechanical parameters of the servo system are determined from the parameters of the mechanical property plane.
In the previous step, the obtained plane is actually the plane corresponding to the equation after the mechanical motion equation of the servo system is integrated, so in the step, according to the obtained mechanical characteristic plane and combined with the sampling length or the time corresponding to the sampling length, the required mechanical parameter can be obtained, and the identification process of the mechanical parameter of the servo system is completed.
According to the invention, by collecting current information, angular velocity information and angular position information of the servo motor at different moments and utilizing the information to obtain a plurality of groups of angular velocity changes, angular changes and accumulated torque impulses of the servo motor, the mechanical characteristic plane of the servo motor can be fitted, and a plurality of mechanical parameters of the servo motor can be determined according to the mechanical characteristic plane of the servo motor. In addition, since the calculation is performed using a plurality of sub-time periods instead of each sampling timing, the influence of the system delay and the system noise on the calculation result can be reduced. Therefore, the invention can effectively and accurately identify the mechanical parameters of the servo system.
In some embodiments, the mechanical parameters of the servo system include a moment of inertia and a viscous friction coefficient, and step S105 may specifically include:
a) And determining a first intersection line formed by the obtained mechanical characteristic plane and a first plane, wherein the first plane is a plane defined by an angular velocity change coordinate axis and an accumulated torque impulse coordinate axis, and further determining the moment of inertia according to the slope of the first intersection line. It will be appreciated that the first intersection of the mechanical property plane with the first plane is in fact the term of the angle change in the plane equation of the mechanical propertySet to zero, due to T in the remainder e 、T f And T G Are constant and therefore the slope of the first intersection is determined by the moment of inertia J. Therefore, the moment of inertia of the servo system can be obtained by combining the time corresponding to the sampling length of each group of data.
b) And determining a second intersection line formed by the obtained mechanical characteristic plane and a second plane, wherein the second plane is a plane defined by an angle position change coordinate axis and a cumulative torque impulse coordinate axis, and further determining a viscous friction coefficient according to the slope of the second intersection line. It will be appreciated that the second intersection of the mechanical property plane with the second plane is in fact the term of the angle change in the plane equation of the mechanical propertySet to zero, due to T in the remainder f And T G Are constant, so that the slope of the second intersection is determined by the coefficient of viscous friction B. Therefore, the viscous friction coefficient of the servo system can be obtained according to the slope of the second intersecting line.
Referring to fig. 2, fig. 2 is a flowchart illustrating a mechanical parameter identification method of a servo system according to another embodiment of the invention. The method comprises the following steps:
s201: the angular acceleration of the servo motor is changed multiple times during multiple tests, wherein the servo motor is rotated forward during one portion of the test and rotated in reverse during another portion of the test.
In this embodiment, in order to further identify other parameters in the mechanical motion equation of the servo system, in step S201, the servo motor is rotated forward during one part of the test process and rotated backward during another part of the test process. It is to be understood that the order of forward rotation and reverse rotation of the servo motor is not limited, and for example, all the tests of forward rotation (reverse rotation) of the servo motor may be completed first and then the test of reverse rotation (forward rotation) may be performed, or the forward rotation test and the reverse rotation test may be alternately performed.
S202: and collecting current information, angular velocity information and angular position information of the servo motor at a plurality of different moments.
S203: and acquiring a plurality of groups of angle position change values, angle speed change values and accumulated torque impulse values under the preset sampling length according to the angle position information, the angle speed information and the current information of the servo motor.
Steps S202 and S203 are similar to steps S102 and S103, and are not described here again for brevity.
S204: fitting a forward mechanical characteristic plane of the servo motor by utilizing a plurality of coordinate points corresponding to forward rotation of the servo motor, and fitting a reverse mechanical characteristic plane of the servo motor by utilizing a plurality of coordinate points corresponding to reverse rotation of the servo motor.
Unlike the foregoing embodiment, in which all coordinate points are used to fit the mechanical characteristic plane of the servo system, in this embodiment, coordinate points obtained during all forward rotation tests of the servo motor are used to fit the forward rotation mechanical characteristic plane of the servo motor, and coordinate points obtained during all reverse rotation tests of the servo motor are used to fit the reverse rotation mechanical characteristic plane of the servo motor. As shown in fig. 6, since the values of the angular position changes of all the coordinate points obtained during the motor forward rotation test are positive, and the values of the angular position changes of all the coordinate points obtained during the motor reverse rotation test are negative, the two coordinate points can be easily distinguished in the coordinate system, and the forward rotation mechanical characteristic plane and the reverse rotation mechanical characteristic plane of the servo motor can be fitted respectively.
S205: the mechanical parameters of the servo system are determined from the parameters of the forward/reverse mechanical property plane.
In this embodiment, the mechanical parameters include moment of inertia, coefficient of viscous friction, off-load weight moment, and kinetic friction moment. Step S205 may specifically include:
a) Determining a first intersection line formed by a forward mechanical characteristic plane and a first plane, and determining a third intersection line formed by a reverse mechanical plane and the first plane, wherein the first plane is a plane defined by an angular velocity change coordinate axis and an accumulated torque impulse coordinate axis; and determining the moment of inertia according to the average value of the slope of the first intersecting line and the slope of the third intersecting line. The step of obtaining the moment of inertia has been explained in the previous embodiment, in which the only difference is that: since the forward mechanical property plane and the reverse mechanical property plane are used, the moment of inertia is determined using the average of the slopes of the first intersecting line and the third intersecting line. An example of the first intersection and the third intersection may refer to fig. 7.
b) And determining the accumulated value of the unbalanced load moment impulse according to the average value of the intercept of the first intersecting line on the accumulated moment impulse coordinate axis and the intercept of the third intersecting line on the accumulated moment impulse coordinate axis, and further determining the unbalanced load moment by combining the sampling length. Still referring to the above equation, the intercept of the first intersection and the third intersection on the cumulative torque axis are respectivelyAnd->Because the direction of the unbalanced load moment is unchanged no matter the motor rotates positively or reversely, namely T G1 ＝ H2 Thus, the common term for both intercepts is the integral of the unbalanced loading moment over time ti-ti+1. And combining the time corresponding to the sampling length, the unbalanced load moment of the servo system can be determined.
c) And determining the accumulated value of the kinetic friction moment according to half of the difference value between the intercept of the first intersecting line on the accumulated moment impulse coordinate axis and the intercept of the third intersecting line on the accumulated moment impulse coordinate axis, and further determining the kinetic friction moment by combining the sampling length. According to the analysis in the previous step, the intercept of the first intersection line and the third intersection line on the accumulated torque impulse coordinate axis is the integral of the kinetic friction moment in the period, and therefore, half the distance between the two intercept points represents the accumulated value of the kinetic friction moment impulse. And combining the time corresponding to the sampling length to determine the dynamic friction moment of the servo system.
d) Determining a second intersection line formed by the forward rotation mechanical characteristic plane and the second plane, and determining a fourth intersection line formed by the reverse rotation mechanical plane and the second plane, wherein the second plane is a plane defined by an angle position change coordinate axis and an accumulated torque impulse coordinate axis. And determining the viscous friction coefficient according to the average value of the slope of the second intersecting line and the slope of the fourth intersecting line. The step of obtaining the viscous friction coefficient has been explained in the foregoing embodiment, and in this embodiment, the difference is only that: since the forward mechanical property plane and the reverse mechanical property plane are used, the average value of the slopes of the second intersecting line and the fourth intersecting line is used to determine the viscous friction coefficient. An example of the second intersection and the fourth intersection may refer to fig. 8.
By implementing the embodiment, the moment of inertia, viscous friction coefficient, unbalanced load moment and dynamic friction moment in the mechanical characteristic parameters of the servo system can be calculated, and the defect that the moment of inertia can only be calculated in the prior art is overcome.
Since the value of the viscous friction coefficient tends to be small, it is easily disturbed by system noise. Therefore, it is necessary to perform a significant test on the coefficient of viscous friction to determine whether the obtained coefficient of viscous friction is effective. The present invention thus also provides an embodiment for significance checking the calculated coefficient of viscous friction.
Referring to fig. 3, fig. 3 is a flow chart illustrating a method for acquiring a mechanical characteristic plane of a servo motor and determining a mechanical parameter of a servo system according to a parameter of the mechanical characteristic plane according to an embodiment of the present invention. The method comprises the following steps:
s301: and respectively grouping a plurality of coordinate points in the testing process corresponding to the forward rotation of the servo motor and a plurality of coordinate points in the testing process corresponding to the reverse rotation of the servo motor according to preset grouping.
Alternatively, the method of grouping the plurality of coordinate points during the test respectively may be random grouping. Alternatively, the coordinate points obtained in each complete test process, i.e., the process of changing the position of the servo motor from zero to a specified position, may be grouped into one set.
S302: and respectively fitting a forward mechanical characteristic plane of a plurality of groups of servo motors and a reverse mechanical characteristic plane of a plurality of groups of servo motors according to the plurality of grouped coordinate points.
S303: and determining a plurality of groups of measured values of viscous friction coefficients according to the plurality of groups of forward mechanical characteristic planes and reverse mechanical characteristic planes of the servo motor, and further determining the viscous friction coefficients.
In step S302 and step S303, by a method similar to the previous embodiment, a plurality of sets of measured values of viscous friction coefficients can be determined from each set of forward mechanical property planes and each set of reverse mechanical property planes of the servo system. The measured value of the viscous friction coefficient is a value calculated according to the slope of the second intersecting line (or the average value of the slopes of the second intersecting line and the fourth intersecting line). All these calculated values of the viscous friction coefficient are averaged to obtain the desired viscous friction coefficient.
S304: t test is carried out on the viscous friction coefficient, and whether the obtained viscous friction coefficient is obviously not zero is judged.
The statistics of the single overall T-test are:
wherein the method comprises the steps ofFor the average number of samples, σ X N is the number of samples, μ is the significance standard for the T test, which is the standard deviation of the samples. Here we check if the viscous friction coefficient is significantly non-zero, so μ=0.
According to the preset threshold value, substituting the standard deviation, average value (i.e. the viscosity friction coefficient determined in the last step) and the group number of the plurality of groups of viscosity friction coefficients into the preset threshold value, and inquiring the corresponding limit value table to know whether the viscosity friction coefficient is obviously not zero.
S305: when the resulting viscous friction coefficient does not meet significantly non-zero, the viscous friction coefficient is updated using empirical values.
When the resulting viscous friction coefficient does not meet significantly non-zero, meaning that it is in fact quite likely to be an error caused by system noise, rather than a true viscous friction coefficient, the viscous friction coefficient is updated using an empirical value (e.g., 0, or the power-6 of 10).
By implementing the embodiment, whether the calculated viscous friction coefficient is caused by a system noise error or not can be judged, and the calculated viscous friction coefficient is updated according to a judgment result, so that errors are avoided.
Referring to fig. 4, fig. 4 is a flowchart illustrating an implementation algorithm of the mechanical parameter identification method of the servo system according to the present invention.
As shown in fig. 4, parameters such as acceleration and position of the servo motor are initialized (zeroed) first, and the number of tests m is set. And then generating S-curve commands of a plurality of angle positions, and controlling the servo motor to act according to the angle positions in the curve in each test process. Meanwhile, information such as angular speed change, angular position change, accumulated torque impulse value and the like is calculated in each test process, and coordinate points of forward and reverse rotation tests are stored. And after all the tests are completed, fitting the forward rotation mechanical characteristic plane and the reverse rotation mechanical characteristic plane by the obtained coordinate points, so as to obtain the required mechanical characteristic parameters of the servo system, namely moment of inertia, kinetic friction moment, unbalanced load moment of force and viscous friction coefficient. Next, T-test is performed on the coefficient of viscous friction B, and when the test result is that the coefficient of viscous friction B does not satisfy significantly non-zero, the coefficient of viscous friction B is updated with the empirical value Br, or the coefficient of viscous friction B is set to 0.
Referring to fig. 5, fig. 5 is a schematic diagram illustrating a servo control system 500 according to an embodiment of the invention. The servo control system 500 includes a communication bus 501, a processor 502, and a memory 503. The processor 502 and the memory 503 are coupled by a communication bus 501.
The memory 503 stores program data, which can be loaded by the processor 502 and executed by the servo system mechanical parameter identification method of any of the above embodiments. It will be appreciated that in other embodiments, the memory 503 may be located in the same physical device as the different processors 502, but that the method of any of the above embodiments may be performed by combining the servo control system 500 with a network. It is understood that the servo control system 500 may be a control system and related devices built in the servo system, or may be an external device and system connected to the servo system, such as a computer, an industrial control device, a signal processing device, etc.
After obtaining each mechanical parameter of the servo system, the servo control system 500 can utilize the obtained parameter value to perform parameter self-tuning on the servo system and perform moment compensation according to the corresponding friction moment, thereby improving the dynamic performance and steady-state performance of the servo system.
The functions described in the above embodiments may be stored in a device having a storage function if implemented in software and sold or used as a separate product, i.e., the present invention also provides a storage device in which a program is stored. Program data in a storage device including, but not limited to, a usb disk, an optical disk, a server, a hard disk, or the like, can be executed to implement the method of acquiring frequency characteristics of a servo system in the above-described embodiments.
The foregoing description is only of embodiments of the present invention, and is not intended to limit the scope of the invention, and all equivalent structures or equivalent processes using the descriptions and the drawings of the present invention or directly or indirectly applied to other related technical fields are included in the scope of the present invention.
Claims (16)
1. A method for identifying mechanical parameters of a servo system, comprising:
the angular acceleration of the servo motor is changed for a plurality of times;
collecting current information, angular velocity information and angular position information of the servo motor at a plurality of different moments;
acquiring a plurality of groups of angular position change values, angular speed change values and accumulated torque impulse values under a preset sampling length according to the angular position information, the angular speed information and the current information of the servo motor;
fitting a mechanical characteristic plane of the servo motor according to the angular position change value, the angular speed change value and the accumulated torque impulse value;
acquiring mechanical parameters of the servo system according to the mechanical characteristic plane;
the step of fitting the mechanical characteristic plane of the servo motor according to the angular position change value, the angular velocity change value and the accumulated torque impulse value comprises the following steps: respectively taking the angular position change, the angular speed change and the accumulated torque impulse as coordinate axes, defining the multiple groups of angular position change values, the angular speed change values and the accumulated torque impulse values as multiple coordinate points in space, and fitting a mechanical characteristic plane of the servo motor by utilizing the multiple coordinate points;
the mechanical parameters include rotational inertia and viscous friction coefficient;
the step of obtaining the mechanical parameters of the servo system according to the mechanical characteristic plane comprises the following steps:
determining a first intersection line formed by the mechanical characteristic plane and a first plane, wherein the first plane is a plane defined by an angular velocity change coordinate axis and an accumulated torque impulse coordinate axis;
determining the moment of inertia according to the slope of the first intersection line;
determining a second intersection line formed by the mechanical characteristic plane and a second plane, wherein the second plane is a plane defined by the angular position change and the accumulated torque impulse coordinate axis;
and determining the viscous friction coefficient according to the slope of the second intersecting line.
2. The method of claim 1, wherein the step of varying the angular acceleration of the servo motor a plurality of times comprises:
and changing the angular acceleration and the angular jerk of the servo motor, so that the angular position of the servo motor is changed from zero to a specified angle, the angular speed of the servo motor is gradually increased from zero, and finally, the angular speed of the servo motor is gradually reduced to zero.
3. The method of claim 1, wherein:
the mechanical property plane comprises a forward mechanical property plane and a reverse mechanical property plane;
the step of fitting the mechanical characteristic plane of the servo motor by using the plurality of coordinate points comprises the following steps:
fitting a forward mechanical characteristic plane of the servo motor by utilizing the plurality of coordinate points corresponding to the forward rotation of the servo motor; and
and fitting a reverse mechanical characteristic plane of the servo motor by utilizing the plurality of coordinate points corresponding to the reverse rotation of the servo motor.
4. A method as claimed in claim 3, wherein:
the mechanical parameters comprise rotational inertia, viscous friction coefficient, unbalanced load gravity moment and dynamic friction moment;
the step of obtaining the mechanical parameters of the servo system according to the mechanical characteristic plane comprises the following steps:
determining a first intersection line formed by the forward rotation mechanical characteristic plane and a first plane and a third intersection line formed by the reverse rotation mechanical characteristic plane and the first plane, wherein the first plane is a plane defined by an angular velocity change coordinate axis and an accumulated torque impulse coordinate axis;
determining the moment of inertia according to the average value of the slope of the first intersecting line and the slope of the third intersecting line;
determining an impulse accumulation value of the unbalanced load moment according to an average value of the intercept of the first intersection line on the accumulated torque impulse coordinate axis and the intercept of the third intersection line on the accumulated torque impulse coordinate axis, and further determining the unbalanced load moment by combining the preset sampling length;
determining an impulse accumulation value of the dynamic friction torque according to half of a difference value between an intercept of the first intersection line on the accumulated torque coordinate axis and an intercept of the third intersection line on the accumulated torque coordinate axis, and further determining the dynamic friction torque by combining the preset sampling length;
determining a second intersection line formed by the forward rotation mechanical characteristic plane and a second plane and a fourth intersection line formed by the reverse rotation mechanical characteristic plane and the second plane, wherein the second plane is a plane defined by the angle position change coordinate axis and the accumulated torque impulse coordinate axis;
and determining the viscous friction coefficient according to the average value of the slope of the second intersecting line and the slope of the fourth intersecting line.
5. A method as claimed in claim 3, wherein:
the step of fitting the forward mechanical characteristic plane of the servo motor by using the plurality of coordinate points corresponding to the forward rotation of the servo motor, and the step of fitting the reverse mechanical characteristic plane of the servo motor by using the plurality of coordinate points corresponding to the reverse rotation of the servo motor, comprises the following steps:
respectively grouping the coordinate points corresponding to forward rotation of the servo motor and the coordinate points corresponding to reverse rotation of the servo motor according to preset grouping;
fitting a plurality of groups of forward mechanical characteristic planes of the servo motors and a plurality of groups of reverse mechanical characteristic planes of the servo motors respectively according to the plurality of coordinate points after grouping;
the step of obtaining the mechanical parameters of the servo system according to the parameters of the mechanical characteristic plane comprises the following steps:
determining a plurality of groups of second intersecting lines formed by a plurality of groups of forward rotation mechanical characteristic planes and a second plane and a plurality of groups of fourth intersecting lines formed by a plurality of groups of reverse rotation mechanical characteristic planes and the second plane, wherein the second plane is a plane defined by the angle position change coordinate axis and the accumulated torque coordinate axis;
and determining a plurality of groups of viscous friction coefficient measurement values according to the slopes of the plurality of groups of second intersecting lines and the average value of the slopes of the corresponding plurality of groups of fourth intersecting lines, and determining the viscous friction coefficient according to the average value of the plurality of groups of viscous friction coefficient measurement values.
6. The method of claim 5, further comprising, after said step of determining said coefficient of friction from an average of said plurality of sets of coefficient of friction measurements:
t test is carried out on the viscous friction coefficient, and whether the viscous friction coefficient is obviously not zero is judged;
if not, the viscous friction coefficient is updated using an empirical value.
7. The method of claim 5, wherein:
the preset packet is a random packet;
the preset group is as follows: and dividing the coordinate points obtained in the process of changing the position of the servo motor from zero to a specified position into a group in each forward rotation or reverse rotation process.
8. The method of claim 1, wherein sampling intervals between any adjacent two of the plurality of sets of angular position change values, angular velocity change values, and accumulated torque impulse values of the servo motor are uniform.
9. The method of claim 8, wherein the length of the sampling interval is less than the preset sampling length.
10. A servo control system comprising a processor, the processor being capable of loading program instructions and performing a method of servo system mechanical parameter identification, the method comprising:
the angular acceleration of the servo motor is changed for a plurality of times;
collecting current information, angular velocity information and angular position information of the servo motor at a plurality of different moments;
acquiring a plurality of groups of angular position change values, angular speed change values and accumulated torque impulse values under a preset sampling length according to the angular position information, the angular speed information and the current information of the servo motor;
fitting a mechanical characteristic plane of the servo motor according to the angular position change value, the angular speed change value and the accumulated torque impulse value;
acquiring mechanical parameters of the servo system according to the mechanical characteristic plane;
the step of fitting the mechanical characteristic plane of the servo motor according to the angular position change value, the angular velocity change value and the accumulated torque impulse value comprises the following steps:
respectively taking the angular position change, the angular speed change and the accumulated torque impulse as coordinate axes, defining the multiple groups of angular position change values, the angular speed change values and the accumulated torque impulse values as multiple coordinate points in space, and fitting a mechanical characteristic plane of the servo motor by utilizing the multiple coordinate points;
the mechanical parameters include rotational inertia and viscous friction coefficient;
the step of obtaining the mechanical parameters of the servo system according to the mechanical characteristic plane comprises the following steps:
determining a first intersection line formed by the mechanical characteristic plane and a first plane, wherein the first plane is a plane defined by an angular velocity change coordinate axis and an accumulated torque impulse coordinate axis;
determining the moment of inertia according to the slope of the first intersection line;
determining a second intersection line formed by the mechanical characteristic plane and a second plane, wherein the second plane is a plane defined by the angular position change and the accumulated torque impulse coordinate axis;
and determining the viscous friction coefficient according to the slope of the second intersecting line.
11. The servo control system of claim 10 wherein:
the mechanical property plane comprises a forward mechanical property plane and a reverse mechanical property plane;
the step of fitting the mechanical characteristic plane of the servo motor by using the plurality of coordinate points comprises the following steps:
fitting a forward mechanical characteristic plane of the servo motor by utilizing the plurality of coordinate points corresponding to the forward rotation of the servo motor; and
and fitting a reverse mechanical characteristic plane of the servo motor by utilizing the plurality of coordinate points corresponding to the reverse rotation of the servo motor.
12. The servo control system of claim 11 wherein:
the mechanical parameters comprise rotational inertia, viscous friction coefficient, unbalanced load gravity moment and dynamic friction moment;
the step of obtaining the mechanical parameters of the servo system according to the mechanical characteristic plane comprises the following steps:
determining a first intersection line formed by the forward rotation mechanical characteristic plane and a first plane and a third intersection line formed by the reverse rotation mechanical characteristic plane and the first plane, wherein the first plane is a plane defined by an angular velocity change coordinate axis and an accumulated torque impulse coordinate axis;
determining the moment of inertia according to the average value of the slope of the first intersecting line and the slope of the third intersecting line;
determining an impulse accumulation value of the unbalanced load moment according to an average value of the intercept of the first intersection line on the accumulated torque impulse coordinate axis and the intercept of the third intersection line on the accumulated torque impulse coordinate axis, and further determining the unbalanced load moment by combining the preset sampling length;
determining an impulse accumulation value of the dynamic friction torque according to half of a difference value between an intercept of the first intersection line on the accumulated torque coordinate axis and an intercept of the third intersection line on the accumulated torque coordinate axis, and further determining the dynamic friction torque by combining the preset sampling length;
determining a second intersection line formed by the forward rotation mechanical characteristic plane and a second plane and a fourth intersection line formed by the reverse rotation mechanical characteristic plane and the second plane, wherein the second plane is a plane defined by the angle position change coordinate axis and the accumulated torque impulse coordinate axis;
and determining the viscous friction coefficient according to the average value of the slope of the second intersecting line and the slope of the fourth intersecting line.
13. The servo control system of claim 11 wherein:
the step of fitting the forward mechanical characteristic plane of the servo motor by using the plurality of coordinate points corresponding to the forward rotation of the servo motor, and the step of fitting the reverse mechanical characteristic plane of the servo motor by using the plurality of coordinate points corresponding to the reverse rotation of the servo motor, comprises the following steps:
respectively grouping the coordinate points corresponding to forward rotation of the servo motor and the coordinate points corresponding to reverse rotation of the servo motor according to preset grouping;
fitting a plurality of groups of forward mechanical characteristic planes of the servo motors and a plurality of groups of reverse mechanical characteristic planes of the servo motors respectively according to the plurality of coordinate points after grouping;
the step of obtaining the mechanical parameters of the servo system according to the parameters of the mechanical characteristic plane comprises the following steps:
determining a plurality of groups of second intersecting lines formed by a plurality of groups of forward rotation mechanical characteristic planes and a second plane and a plurality of groups of fourth intersecting lines formed by a plurality of groups of reverse rotation mechanical characteristic planes and the second plane, wherein the second plane is a plane defined by the angle position change coordinate axis and the accumulated torque coordinate axis;
and determining a plurality of groups of viscous friction coefficient measurement values according to the slopes of the plurality of groups of second intersecting lines and the average value of the slopes of the corresponding plurality of groups of fourth intersecting lines, and determining the viscous friction coefficient according to the average value of the plurality of groups of viscous friction coefficient measurement values.
14. The servo control system of claim 13 wherein after said step of determining said coefficient of friction from an average of said plurality of sets of coefficient of friction measurements, further comprising:
t test is carried out on the viscous friction coefficient, and whether the viscous friction coefficient is obviously not zero is judged;
if not, the viscous friction coefficient is updated using an empirical value.
15. The servo control system of claim 13 wherein:
the preset packet is a random packet;
the preset group is as follows: and dividing the coordinate points obtained in the process of changing the position of the servo motor from zero to a specified position into a group in each forward rotation or reverse rotation process.
16. A device with a memory function, characterized in that program instructions are stored, which can be loaded and executed to implement the servo system mechanical parameter identification method according to any one of claims 1-9.
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| PCT/CN2018/115089 WO2020097770A1 (en) | 2018-11-12 | 2018-11-12 | Method for recognizing mechanical parameter of servo system, servo control system, and storage device |
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| CN106533291A (en) * | 2016-08-31 | 2017-03-22 | 东菱技术有限公司 | Inertia identification and load torque observation-based speed loop response improvement method |
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| CN103227611A (en) * | 2013-03-27 | 2013-07-31 | 华为技术有限公司 | Mechanical inertia identification method and device, and motor speed regulation system |
| CN104639004A (en) * | 2015-02-09 | 2015-05-20 | 华中科技大学 | Online identification method for mechanical parameters of permanent magnet synchronous motor |
| CN106330036A (en) * | 2016-09-22 | 2017-01-11 | 四川长虹电器股份有限公司 | Identification control method of rotational inertia of motor |
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