Calculation method of torque-speed characteristics of annular traveling wave ultrasonic motor considering stator tooth structure

Abstract

The present invention discloses a method for calculating the torque and speed characteristics of an annular traveling wave type ultrasonic motor taking into account the stator tooth structure, comprising: obtaining basic parameters of the annular traveling wave type ultrasonic motor and structural parameters of the stator teeth, calculating the torque and speed characteristics of the annular traveling wave type ultrasonic motor and the stator tooth structure, and N The corresponding motor output torque T L ; Judgment and rotor speed N The corresponding motor output torque T L The size of T L >0, reset the rotor speed N The value of and calculate the rotor speed N The corresponding motor output torque T L ;like T L ≤0, end the calculation; according to the speed of all rotors in the calculation process N And its corresponding motor output torque T L The present invention takes into account the structural parameters of the stator teeth, can realize simple and effective calculation of the torque-speed characteristics of the annular traveling wave type ultrasonic motor, and can calculate the torque-speed characteristics of the annular traveling wave type ultrasonic motor in the design and analysis stage of the motor.

Description

Technical Field

[0001] The invention relates to a calculation method for the torque and speed characteristics of an annular traveling wave type ultrasonic motor taking into account a stator tooth structure, and belongs to the technical field of ultrasonic motors. Background Art

[0002] The circular traveling wave ultrasonic motor uses the inverse piezoelectric effect of piezoelectric ceramics to convert high-frequency alternating current into ultrasonic vibration of metal elastic body, and then converts the ultrasonic vibration of metal elastic body into the rotational motion of rotor through contact friction. Ultrasonic motor has many advantages, such as low speed and high torque, power-off self-locking, fast dynamic response, etc., and has broad application prospects in the fields of non-continuous motion, precision control, intelligent robots and so on.

[0003] Torque-speed characteristics are one of the important properties of ultrasonic motors. The calculation of the torque-speed characteristics of ultrasonic motors is difficult due to complex nonlinear problems such as contact and friction. The stator of a ring-shaped traveling wave ultrasonic motor is generally provided with a stator tooth structure to amplify the tangential vibration of the stator. The stator tooth structure makes the contact and friction problems between the stator and rotor more complicated, increasing the difficulty of accurately calculating the torque-speed characteristics of the motor. A simplified approach is to ignore the structure of the stator teeth and directly regard the stator surface as continuous, but this simplified approach often leads to large errors. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for calculating the torque-speed characteristics of an annular traveling wave type ultrasonic motor with a stator tooth structure. Considering the structural parameters of the stator teeth, a simple and effective calculation of the torque-speed characteristics of an annular traveling wave type ultrasonic motor can be achieved, and the torque-speed characteristics of an annular traveling wave type ultrasonic motor can be calculated in the design and analysis stage of the motor. To achieve the above purpose, the present invention is implemented by adopting the following technical solutions:

[0005] In a first aspect, the present invention provides a method for calculating the torque-speed characteristics of an annular traveling wave ultrasonic motor taking into account the stator tooth structure, comprising:

[0006] Obtain the basic parameters of the ring-shaped traveling wave ultrasonic motor and the structural parameters of the stator teeth;

[0007] Based on the basic parameters of the annular traveling wave ultrasonic motor, the structural parameters of the stator teeth and the preset value of the rotor speed N, the motor output torque T corresponding to the rotor speed N is calculated. L ;

[0008] Determine the motor output torque T corresponding to the rotor speed N L The size of T L > 0, increase the value of the rotor speed N and calculate the motor output torque T corresponding to the rotor speed N LIf T L ≤0, end the calculation;

[0009] According to the calculation process, all rotor speeds N and their corresponding motor output torque T L , determine the torque-speed characteristics of the ring-shaped traveling wave ultrasonic motor.

[0010] In combination with the first aspect, further, the basic parameters of the annular traveling wave ultrasonic motor include: elastic modulus E of the friction material, friction coefficient μ, stator amplitude A, stator vibration frequency f, peak number n of the stator working mode, preload F between the stator and rotor n , the average contact radius of stator and rotor r, the radial contact width of stator and rotor b, the thickness of friction material h, and the distance a from the stator tooth surface to the neutral plane.

[0011] In combination with the first aspect, further, the structural parameters of the stator teeth include: the number of stator teeth n t 、The circumferential angle θ occupied by a single stator tooth t .

[0012] In combination with the first aspect, further, the motor output torque T corresponding to the rotor speed N is calculated. L , calculated by the following formula:

[0013]

[0014] In formula (1), θ t is the circumferential angle occupied by a single stator tooth, n t is the number of stator teeth; t is time, t1 is the contact start time, t2 is the contact end time, t eq1 is the first constant velocity time point, t eq2 is the second isokinetic time point.

[0015] In combination with the first aspect, further, the contact start time t1 and the contact end time t2 are calculated by the following formula:

[0016]

[0017] Among them, θ t is the circumferential angle occupied by a single stator tooth, n t is the number of stator teeth, f is the stator vibration frequency, the contact start time t1 is obtained by formula (2), and the range of the contact start time t1 is obtained by formula (3);

[0018]

[0019] The contact end time t2 is obtained by equation (4).

[0020] In combination with the first aspect, further, the first constant speed time point t eq1 and the second isokinetic time point t eq2 , calculated by the following formula:

[0021]

[0022] The first constant speed time point t calculated by judgment formula (5) eq1 With the contact start time t1, if t eq1 <t1, take t eq1 =t1; if t eq1 ≥t1, output the calculated first constant speed time point t eq1 ;

[0023]

[0024] In formula (6), f is the stator vibration frequency, t eq1 is the first constant speed time point, and the second constant speed time point t is calculated by formula (6) eq2 .

[0025] In combination with the first aspect, further, the value of the rotor speed N is increased and the motor output torque T corresponding to the rotor speed N is calculated. L include:

[0026] Add the step constant Q to the value of the rotor speed N to obtain the increased value of the rotor speed N;

[0027] According to the basic parameters of the annular traveling wave ultrasonic motor, the structural parameters of the stator teeth and the increased rotor speed N, the motor output torque T corresponding to the increased rotor speed N is calculated. L .

[0028] In combination with the first aspect, optionally, the value range of the step constant Q is 0<Q≤10.

[0029] In a second aspect, the present invention provides a calculation system for the torque and speed characteristics of an annular traveling wave ultrasonic motor taking into account the stator tooth structure, comprising:

[0030] Acquisition module: used to obtain the basic parameters of the ring-shaped traveling wave ultrasonic motor and the structural parameters of the stator teeth;

[0031] Calculation module: used to calculate the motor output torque T corresponding to the rotor speed N based on the basic parameters of the annular traveling wave ultrasonic motor, the structural parameters of the stator teeth and the preset rotor speed N. L ;

[0032] Judgment module: used to judge the motor output torque T corresponding to the rotor speed N L The size of TL > 0, increase the value of the rotor speed N and calculate the motor output torque T corresponding to the rotor speed N L If T L ≤0, end the calculation;

[0033] Torque-speed characteristic confirmation module: used to calculate all rotor speeds N and their corresponding motor output torque T during the calculation process L , determine the torque-speed characteristics of the ring-shaped traveling wave ultrasonic motor.

[0034] In a third aspect, the present invention provides a computer device, including a processor and a storage medium;

[0035] The storage medium is used to store instructions;

[0036] The processor is used to operate according to the instructions to execute the steps of the method according to the first aspect.

[0037] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the steps of the method described in the first aspect.

[0038] Compared with the prior art, the method for calculating the torque and speed characteristics of the annular traveling wave ultrasonic motor taking into account the stator tooth structure provided in the embodiment of the present invention has the following beneficial effects:

[0039] The present invention obtains basic parameters of the annular traveling wave type ultrasonic motor and structural parameters of the stator teeth, and calculates the motor output torque T corresponding to the rotor speed N based on the basic parameters of the annular traveling wave type ultrasonic motor, the structural parameters of the stator teeth and the value of the preset rotor speed N. L ; The present invention takes into account the structural parameters of the stator teeth;

[0040] The present invention determines the motor output torque T corresponding to the rotor speed N L The size of T L > 0, increase the value of the rotor speed N and calculate the motor output torque T corresponding to the rotor speed N L If T L ≤0, end the calculation; according to all rotor speeds N and their corresponding motor output torque T during the calculation process L , determine the torque-speed characteristics of the annular traveling wave type ultrasonic motor; the present invention has a simple calculation process and high calculation efficiency, and can effectively calculate the torque-speed characteristics of the annular traveling wave type ultrasonic motor in the design and analysis stage of the motor;

[0041] The present invention performs calculations based on the basic parameters of the annular traveling wave type ultrasonic motor and the structural parameters of the stator teeth, has strong adaptability, and can calculate the torque-speed characteristics of annular traveling wave type ultrasonic motors of different sizes; the present invention can also be used for the structural design and optimization analysis of the annular traveling wave type ultrasonic motor to improve the torque-speed performance of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a flow chart of a method for calculating the torque and speed characteristics of an annular traveling wave type ultrasonic motor taking into account the stator tooth structure in the first embodiment of the present invention;

[0043] Figure 2 It is a schematic diagram of the calculation curve of the torque-speed characteristics of the annular traveling wave ultrasonic motor considering the stator tooth structure in the second embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0045] Embodiment 1:

[0046] like Figure 1 As shown, a method for calculating the torque-speed characteristics of an annular traveling wave ultrasonic motor considering the stator tooth structure includes:

[0047] Step 1: Obtain the basic parameters of the ring traveling wave ultrasonic motor.

[0048] The basic parameters of the ring-shaped traveling wave ultrasonic motor include: elastic modulus E of the friction material, friction coefficient μ, stator amplitude A, stator vibration frequency f, number of peaks n of the stator working mode, preload F between the stator and rotor n , the average contact radius of stator and rotor r, the radial contact width of stator and rotor b, the thickness of friction material h, and the distance a from the stator tooth surface to the neutral plane.

[0049] Step 2: Obtain the structural parameters of the stator teeth.

[0050] Structural parameters of stator teeth, including: Number of stator teeth n t 、The circumferential angle θ occupied by a single stator tooth t .

[0051] Step 3: Calculate the contact start time t1 by the following formula:

[0052]

[0053] The calculated contact start time t1 falls within the following range:

[0054]

[0055] In formula (2), f is the stator vibration frequency.

[0056] Step 4: Calculate the contact end time t2 by the following formula:

[0057]

[0058] In formula (3), f is the stator vibration frequency, and t1 is the contact start time.

[0059] Step 5: Assume that the initial value of the rotor speed N is 0.

[0060] Step 6: Calculate the first constant velocity time point t eq1 , calculated by the following formula:

[0061]

[0062] The first constant speed time point t calculated by judgment formula (4) eq1 With the contact start time t1, if t eq1 <t1, take t eq1 =t1; if t eq1 ≥t1, output the calculated first constant speed time point t eq1 .

[0063] Step 7: Calculate the second constant velocity time point t eq2 , calculated by the following formula:

[0064]

[0065] In formula (5), f is the stator vibration frequency, t eq1 is the first isokinetic time point.

[0066] Step 8: Calculate the motor output torque T corresponding to the rotor speed N L , calculated by the following formula:

[0067]

[0068] In formula (6), θ t is the circumferential angle occupied by a single stator tooth, n t is the number of stator teeth, t is time, t1 is the contact start time, t2 is the contact end time, t eq1 is the first constant velocity time point, t eq2 is the second isokinetic time point.

[0069] Step 9: Determine the motor output torque T corresponding to the rotor speed N L size.

[0070] If TL > 0, increase the value of the rotor speed N and calculate the motor output torque T corresponding to the rotor speed N L If T L ≤0, end the calculation.

[0071] Increasing the value of the rotor speed N includes: adding the step constant Q to the value of the rotor speed N to obtain the increased value of the rotor speed N.

[0072] The value range of the step constant Q is 0<Q≤10. The smaller the value, the more points are calculated and the higher the accuracy. Preferably, the value of Q is 5.

[0073] Step 10: According to the calculation process, all rotor speeds N and their corresponding motor output torque T L , determine the torque-speed characteristics of the ring-shaped traveling wave ultrasonic motor.

[0074] Embodiment 2:

[0075] This embodiment is a specific application scenario of the method for calculating the torque-speed characteristics of an annular traveling wave ultrasonic motor taking into account the stator tooth structure provided in Embodiment 1. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention.

[0076] Take a 60mm diameter annular traveling wave ultrasonic motor as an example. Figure 1 Provide a detailed description of each step.

[0077] Step 1: Obtain the basic parameters of the ring traveling wave ultrasonic motor.

[0078] The basic parameters of the annular traveling wave ultrasonic motor are: elastic modulus of friction material E = 6.67 × 10 8 N / m 2 , friction coefficient μ = 0.14, stator amplitude A = 2 μm, stator vibration frequency f = 41 kHz, number of peaks of stator working mode n = 9, preload F between stator and rotor n =250N, average contact radius of stator and rotor r=27mm, radial contact width of stator and rotor b=2mm, thickness of friction material h=0.5mm, distance from stator tooth surface to neutral plane a=2.5mm.

[0079] Step 2: Obtain the structural parameters of the stator teeth.

[0080] Number of stator teeth n t = 90, the circumferential angle θ occupied by a single stator tooth t =3°.

[0081] Step 3: Calculate the contact start time t1, and get t1 = -3.7655 × 10 -7 s, falls on within the range.

[0082] Step 4: Calculate the contact end time t2, and get t2 = 1.2572 × 10 -5 s.

[0083] Step 5: Assume that the initial value of the rotor speed N is 0 r / min.

[0084] Step 6: Calculate the first constant velocity time point t eq1 , when N = 0r / min, t eq1 = 0s, and t eq1 >t1.

[0085] Step 7: Calculate the second constant velocity time point t eq2 , when N = 0r / min, t eq2 =1.2195×10 -5 s.

[0086] Step 8: Calculate the motor output torque T corresponding to the rotor speed N L , when the speed N = 0r / min, the corresponding output torque T L =0.9373Nm.

[0087] Step 9: Determine the motor output torque T corresponding to the rotor speed N L size.

[0088] If T L > 0, increase the value of the rotor speed N and calculate the motor output torque T corresponding to the rotor speed N L ; If T L ≤0, end the calculation.

[0089] Increasing the value of the rotor speed N includes: adding the value of the rotor speed N to the step constant Q to obtain the increased value of the rotor speed N. In this embodiment, the step constant Q=5.0 r / min, and returning to step 6.

[0090] Step 10: According to the calculation process, all rotor speeds N and their corresponding motor output torque T L , determine the torque-speed characteristics of the ring-shaped traveling wave ultrasonic motor.

[0091] like Figure 2The torque-speed characteristic curve of the annular traveling wave ultrasonic motor considering the stator tooth structure is shown. The embodiment of the present invention uses MATLAB to write a calculation program, manually inputs the basic parameters of the annular traveling wave ultrasonic motor and the structural parameters of the stator teeth, and can quickly give the corresponding torque-speed characteristic curve.

[0092] The calculation method of the torque-speed characteristics of the annular traveling wave type ultrasonic motor of the present invention has a simple calculation process and high calculation efficiency, takes into account the structural parameters of the stator teeth, and can accurately calculate the torque-speed characteristics of the annular traveling wave type ultrasonic motor in the design and analysis stage of the motor; the present invention has strong adaptability and can calculate the torque-speed characteristics of annular traveling wave type ultrasonic motors of different sizes; the present invention can also be used for the structural design and optimization analysis of the annular traveling wave type ultrasonic motor to improve the torque-speed performance of the motor.

[0093] Embodiment three:

[0094] The embodiment of the present invention provides a calculation system for the torque and speed characteristics of an annular traveling wave ultrasonic motor taking into account the stator tooth structure, including:

[0095] Acquisition module: used to obtain the basic parameters of the ring-shaped traveling wave ultrasonic motor and the structural parameters of the stator teeth;

[0096] Calculation module: used to calculate the motor output torque T corresponding to the rotor speed N based on the basic parameters of the annular traveling wave ultrasonic motor, the structural parameters of the stator teeth and the preset rotor speed N. L ;

[0097] Judgment module: used to judge the motor output torque T corresponding to the rotor speed N L The size of T L > 0, increase the value of the rotor speed N and calculate the motor output torque T corresponding to the rotor speed N L ; If T L ≤0, end the calculation;

[0098] Torque-speed characteristic confirmation module: used to calculate all rotor speeds N and their corresponding motor output torque T during the calculation process L , determine the torque-speed characteristics of the ring-shaped traveling wave ultrasonic motor.

[0099] Embodiment 4:

[0100] An embodiment of the present invention provides a computer device, including a processor and a storage medium;

[0101] The storage medium is used to store instructions;

[0102] The processor is used to operate according to the instructions to execute the steps of the method according to the first embodiment.

[0103] Embodiment five:

[0104] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the program implements the steps of the method described in the first embodiment when executed by a processor.

[0105] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0106] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0107] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0108] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0109] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for calculating the torque-speed characteristics of an annular traveling wave ultrasonic motor taking into account the stator tooth structure, characterized in that: include: Obtain the basic parameters of the annular traveling wave ultrasonic motor and the structural parameters of the stator teeth; wherein the basic parameters of the annular traveling wave ultrasonic motor include: the elastic modulus E of the friction material, the friction coefficient μ, the stator amplitude A, the stator vibration frequency f, the number of peaks n of the stator working mode, the preload F between the stator and the rotor n , average contact radius of stator and rotor r, radial contact width of stator and rotor b, thickness of friction material h, distance a from stator tooth surface to neutral plane; Based on the basic parameters of the annular traveling wave ultrasonic motor, the structural parameters of the stator teeth and the preset value of the rotor speed N, the motor output torque T corresponding to the rotor speed N is calculated. L ; Wherein, the calculation corresponds to the motor output torque T of the rotor speed N L , calculated by the following formula: In formula (1), θ t is the circumferential angle occupied by a single stator tooth, n t is the number of stator teeth; t is time, t1 is the contact start time, t2 is the contact end time, t eq1 is the first constant velocity time point, t eq2 is the second isokinetic time point; Among them, the contact start time t1 and the contact end time t2 are calculated by the following formula: Among them, θ t is the circumferential angle occupied by a single stator tooth, n t is the number of stator teeth, f is the stator vibration frequency, the contact start time t1 is obtained by formula (2), and the range of the contact start time t1 is obtained by formula (3); The contact end time t2 is obtained by formula (4); Among them, the first constant velocity time point t eq1 and the second isokinetic time point t eq2 , calculated by the following formula: The first constant speed time point t calculated by judgment formula (5) eq1 With the contact start time t1, if t eq1 <t1, take t eq1 =t1; if t eq1 ≥t1, output the calculated first constant speed time point t eq1 ; In formula (6), f is the stator vibration frequency, t eq1 is the first constant speed time point, and the second constant speed time point t is calculated by formula (6) eq2 ; Determine the motor output torque T corresponding to the rotor speed N L The size of T L > 0, increase the value of the rotor speed N and calculate the motor output torque T corresponding to the rotor speed N L If T L ≤0, end the calculation; According to the calculation process, all rotor speeds N and their corresponding motor output torque T L , determine the torque-speed characteristics of the ring-shaped traveling wave ultrasonic motor; Among them, the value of the rotor speed N is increased and the motor output torque T corresponding to the rotor speed N is calculated L include: Add the step constant Q to the value of the rotor speed N to obtain the increased value of the rotor speed N; According to the basic parameters of the annular traveling wave ultrasonic motor, the structural parameters of the stator teeth and the increased rotor speed N, the motor output torque T corresponding to the increased rotor speed N is calculated. L .

2. The method for calculating the torque-speed characteristics of an annular traveling wave ultrasonic motor considering the stator tooth structure according to claim 1, characterized in that: The structural parameters of the stator teeth include: the number of stator teeth n t 、The circumferential angle θ occupied by a single stator tooth t .

3. A calculation system for the torque-speed characteristics of an annular traveling wave type ultrasonic motor considering the stator tooth structure based on the calculation method for the torque-speed characteristics of an annular traveling wave type ultrasonic motor considering the stator tooth structure of claim 1, characterized in that: include: Acquisition module: used to obtain the basic parameters of the ring-shaped traveling wave ultrasonic motor and the structural parameters of the stator teeth; Calculation module: used to calculate the motor output torque T corresponding to the rotor speed N based on the basic parameters of the annular traveling wave ultrasonic motor, the structural parameters of the stator teeth and the preset rotor speed N. L ; Judgment module: used to judge the motor output torque T corresponding to the rotor speed N L The size of T L > 0, increase the value of the rotor speed N and calculate the motor output torque T corresponding to the rotor speed N L If T L ≤0, end the calculation; Torque-speed characteristic confirmation module: used to calculate all rotor speeds N and their corresponding motor output torque T during the calculation process L , determine the torque-speed characteristics of the ring-shaped traveling wave ultrasonic motor.

4. A computer device, characterized in that: including processor and storage medium; The storage medium is used to store instructions; The processor is used to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 2.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 2 are implemented.

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