Calculation method and system for torque-speed characteristics of circular traveling wave ultrasonic motor

Abstract

The present invention discloses a method and system for calculating the torque and speed characteristics of an annular traveling wave type ultrasonic motor. The method comprises: obtaining basic parameters of the annular traveling wave type ultrasonic motor; based on the basic parameters of the annular traveling wave type ultrasonic motor and a preset rotor speed N The value of is calculated with the rotor speed 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 , determine the torque-speed characteristics of the annular traveling wave type ultrasonic motor. The present invention 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 and system for the torque and speed characteristics of a ring-shaped traveling wave ultrasonic motor, belonging 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. It is difficult to calculate the torque-speed characteristics of ultrasonic motors due to complex nonlinear problems such as contact and friction. How to simply and effectively calculate the torque-speed characteristics of the motor in the design stage of the motor in order to analyze and optimize the performance of the motor is an urgent problem to be solved in the ring-type traveling wave ultrasonic motor. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method and system for calculating the torque-speed characteristics of a circular traveling wave type ultrasonic motor, which can realize simple and effective calculation of the torque-speed characteristics of the circular traveling wave type ultrasonic motor and can calculate the torque-speed characteristics of the circular traveling wave type ultrasonic motor 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 a circular traveling wave ultrasonic motor, comprising:

[0006] Obtain the basic parameters of the annular traveling wave ultrasonic motor, and calculate the motor output torque T corresponding to the rotor speed N based on the basic parameters of the annular traveling wave ultrasonic motor and the preset value of the rotor speed N. L ;

[0007] 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;

[0008] 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.

[0009] 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.

[0010] In combination with the first aspect, further, the motor output torque T corresponding to the rotor speed N is L , calculated by the following formula:

[0011]

[0012] In formula (1), t is time, t1 is the contact start time, t2 is the contact end time, and t eq1 is the first constant velocity time point, t eq2 is the second isokinetic time point.

[0013] In combination with the first aspect, further, the contact start time t1 is calculated by the following formula:

[0014]

[0015] And the contact start time t1 falls within the following range:

[0016]

[0017] In formula (3), f is the stator vibration frequency.

[0018] In combination with the first aspect, further, the contact end time t2 is calculated by the following formula:

[0019]

[0020] In formula (4), f is the stator vibration frequency, and t1 is the contact start time.

[0021] In combination with the first aspect, further, the first constant speed time point t eq1 , calculated by the following formula:

[0022]

[0023] 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 .

[0024] In combination with the first aspect, further, the second constant speed time point t eq2 , calculated by the following formula:

[0025]

[0026] In formula (6), f is the stator vibration frequency, t eq1 is the first isokinetic time point.

[0027] 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:

[0028] Add the step constant Q to the value of the rotor speed N to obtain the increased value of the rotor speed N;

[0029] According to the basic parameters of the annular traveling wave ultrasonic motor and the increased rotor speed N, the motor output torque T corresponding to the increased rotor speed N is calculated. L .

[0030] In combination with the first aspect, optionally, the value range of the step constant Q is 0<Q≤10.

[0031] In a second aspect, the present invention provides a system for calculating the torque and speed characteristics of a circular traveling wave ultrasonic motor, comprising:

[0032] Acquisition module: used to obtain the basic parameters of the ring-shaped traveling wave ultrasonic motor;

[0033] 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 and the preset rotor speed N. L ;

[0034] 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;

[0035] 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.

[0036] In a third aspect, the present invention provides a computer-readable storage medium storing one or more programs, characterized in that the one or more programs include instructions, which, when executed by a computing device, enable the computing device to perform any of the methods described in the first aspect.

[0037] Compared with the prior art, the method and system for calculating the torque and speed characteristics of the annular traveling wave ultrasonic motor provided by the embodiment of the present invention have the following beneficial effects:

[0038] The present invention obtains basic parameters of the annular traveling wave type ultrasonic motor, and based on the basic parameters of the annular traveling wave type ultrasonic motor and the value of the preset rotor speed N, calculates the motor output torque T corresponding to the rotor speed N. L ; 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 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;

[0039] The present invention performs calculations based on basic parameters of annular traveling wave ultrasonic motors, has strong adaptability, and can calculate the torque-speed characteristics of annular traveling wave ultrasonic motors of different sizes; the present invention can also be used for structural design and optimization analysis of annular traveling wave ultrasonic motors to improve the torque-speed performance of the motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a flow chart of a method for calculating the torque and speed characteristics of a circular traveling wave type ultrasonic motor in Embodiment 1 of the present invention;

[0041] Figure 2 It is a schematic diagram of the torque-speed characteristic calculation curve of the traveling wave type ultrasonic motor in the second embodiment of the present invention. DETAILED DESCRIPTION

[0042] 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.

[0043] Embodiment 1:

[0044] like Figure 1As shown, the calculation method of the torque-speed characteristics of the annular traveling wave ultrasonic motor includes the following steps:

[0045] Step 1: Obtain the basic parameters of the ring traveling wave ultrasonic motor.

[0046] 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.

[0047] Step 2: Calculate the contact start time t1 by the following formula:

[0048]

[0049] The calculated contact start time t1 falls within the following range:

[0050]

[0051] In formula (2), f is the stator vibration frequency.

[0052] Step 3: Calculate the contact end time t2 by the following formula:

[0053]

[0054] In formula (3), f is the stator vibration frequency and t1 is the contact start time.

[0055] Step 4: Assume that the initial value of the rotor speed N is 0.

[0056] Step 5: Calculate the first constant velocity time point t eq1 , calculated by the following formula:

[0057]

[0058] 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 .

[0059] Step 6: Calculate the second constant velocity time point t eq2 , calculated by the following formula:

[0060]

[0061] In formula (5), f is the stator vibration frequency, t eq1 is the first isokinetic time point.

[0062] Step 7: Calculate the motor output torque T corresponding to the rotor speed N L , calculated by the following formula:

[0063]

[0064] In formula (6), t is time, t1 is the contact start time, t2 is the contact end time, and t eq1 is the first constant velocity time point, t eq2 is the second isokinetic time point.

[0065] Step 8: Determine the motor output torque T corresponding to the rotor speed N L size.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] Step 9: 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.

[0070] Embodiment 2:

[0071] This embodiment is a specific application scenario of the calculation method of the torque-speed characteristics of the circular traveling wave ultrasonic motor provided in the first embodiment. 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.

[0072] Take a 60mm diameter annular traveling wave ultrasonic motor as an example. Figure 1 Provide a detailed description of each step.

[0073] Step 1: Obtain the basic parameters of the ring traveling wave ultrasonic motor.

[0074] The basic parameters of the annular traveling wave ultrasonic motor are: elastic modulus of friction material E = 6.67 × 108 N / m 2 , coefficient of friction μ = 0.14, stator amplitude A = 2 μm, stator vibration frequency f = 41 kHz, number of wave crests n of the stator working mode = 9, pre-pressure F between the stator and the rotor n = 250 N, average contact radius r between the stator and the rotor = 27 mm, radial contact width b between the stator and the rotor = 2 mm, thickness h of the friction material = 0.5 mm, distance a from the surface of the stator tooth to the neutral plane = 2.5 mm.

[0075] Step 2: Calculate the contact start time t1, and it is calculated that t1 = 3.3685×10 -7 s, which falls within the range.

[0076] Step 3: Calculate the contact end time t2, and it is calculated that t2 = 1.1858×10 -5 s.

[0077] Step 4: Set the initial value of the rotor speed N to 0 r / min.

[0078] Step 5: Calculate the first constant-speed time point t eq1 , when N = 0 r / min, it is calculated that t eq1 = 0 s. Since t eq1 < t1, therefore, take t eq1 = t1 = 3.3685×10 -7 s.

[0079] Step 6: Calculate the second constant-speed time point t eq2 , when N = 0 r / min, it is calculated that t eq2 = 1.1858×10 -5 s.

[0080] Step 7: Calculate the motor output torque T L corresponding to the rotor speed N. When the speed N = 0 r / min, the corresponding output torque T L = 0.9450 Nm.

[0081] Step 8: Judge the magnitude of the motor output torque T L corresponding to the rotor speed N.

[0082] If T L > 0, increase the value of the rotor speed N and calculate the motor output torque T L corresponding to the rotor speed N; if T L ≤ 0, end the calculation.

[0083] 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 5.

[0084] Step 9: 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.

[0085] like Figure 2 As shown, the torque-speed characteristic curve of the circular traveling wave ultrasonic motor obtained by cyclic calculation is connected to form the torque-speed characteristic curve. The embodiment of the present invention uses MATLAB to write a calculation program, manually inputs the basic parameters of the circular traveling wave ultrasonic motor, and can quickly give the corresponding torque-speed characteristic curve.

[0086] The calculation method of the annular traveling wave type ultrasonic motor torque-speed characteristics of 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; 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.

[0087] Embodiment three:

[0088] The embodiment of the present invention provides a system for calculating the torque and speed characteristics of a ring-shaped traveling wave ultrasonic motor, comprising:

[0089] Acquisition module: used to obtain the basic parameters of the ring-shaped traveling wave ultrasonic motor;

[0090] 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 and the preset rotor speed N. L ;

[0091] 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;

[0092] 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.

[0093] Embodiment 4:

[0094] An embodiment of the present invention further provides a computer-readable storage medium storing one or more programs, wherein the one or more programs include instructions, and when the instructions are executed by a computing device, the computing device executes the steps in the method described in embodiment 1.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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 a circular traveling wave ultrasonic motor, characterized in that: include: Obtain the basic parameters of the annular traveling wave ultrasonic motor; wherein 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, number of peaks n of the stator working mode, preload F between the stator and 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 and the preset rotor speed N, the motor output torque T corresponding to the rotor speed N is calculated. L ; Among them, the motor output torque T corresponding to the rotor speed N L , calculated by the following formula: In formula (1), t is time, t1 is the contact start time, t2 is the contact end time, and t eq1 is the first constant velocity time point, t eq2 is the second isokinetic time point; Among them, the contact start time t1 is calculated by the following formula: And the contact start time t1 falls within the following range: In formula (3), f is the stator vibration frequency; The contact end time t2 is calculated by the following formula: In formula (4), f is the stator vibration frequency, t1 is the contact start time; Among them, the first constant velocity time point t eq1 , 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 ; Among them, the second constant speed time point t eq2 , calculated by the following formula: In formula (6), f is the stator vibration frequency, t eq1 is the first isokinetic time point; 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 and the increased rotor speed N, the motor output torque T corresponding to the increased rotor speed N is calculated. L .

2. A system for calculating the torque-speed characteristics of a circular traveling wave type ultrasonic motor based on the method for calculating the torque-speed characteristics of a circular traveling wave type ultrasonic motor according to claim 1, characterized in that: include: Acquisition module: used to obtain the basic parameters of the ring-shaped traveling wave ultrasonic motor; 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 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.

3. A computer-readable storage medium storing one or more programs, characterized in that: The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform the method of claim 1 .

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