A method for identifying dynamic torque of a drive chain

Abstract

The application provides a transmission chain dynamic torque identification method, and belongs to the field of automatic control and machinery. The method comprises the following steps: running test is performed on the transmission chain mechanism to obtain partial structural response; the transmission chain related mode shape matrix is calculated, the overall generalized coordinates of the transmission chain are calculated according to the mode shape matrix components of the measurement position and the structural response, and the generalized coordinate matrix is constructed; the modal torque at the position of the dynamic torque to be identified of the transmission chain is calculated, and the modal torque matrix is constructed; and the dynamic torque to be identified of the transmission chain is calculated according to the generalized coordinate matrix and the modal torque matrix at the position of the dynamic torque to be identified. The overall generalized coordinates of the transmission chain are obtained by using the modal superposition theory, the torque at the position which is inconvenient to directly measure can be identified, various different forms of response data can be used, the requirement for the response data is low, the calculation amount is low, the subsequent application in servo real-time control is facilitated, the method can be applied to various types of mechanical mechanisms containing transmission chains, and is of great significance to servo debugging and servo control.

Description

Technical Field

[0001] This invention relates to the fields of automatic control and mechanics, and in particular to a method for identifying dynamic torque in a transmission chain. This method can be applied to various mechanical devices and equipment containing servo transmission mechanisms to identify the dynamic torque at various positions in the transmission chain. Background Technology

[0002] In the fields of automatic control and mechanics, there is a problem of identifying "axis torque." "A shaft" can be any link in the transmission chain, such as a motor shaft, a reducer output shaft, etc.; "torque" usually refers to the internal force of the shaft, mainly the torque around the shaft. Torque is generally divided into dynamic and static components. Static torque is usually a torque with a stable amplitude and slow change, while dynamic torque has a rapidly changing amplitude, exhibiting as a vibration torque with a mean of 0. The magnitude of dynamic torque affects the accuracy of automatic control. Accurately identifying the dynamic torque on each axis greatly helps improve the accuracy of servo control.

[0003] Currently, there are several methods for identifying dynamic torque on a shaft: 1. Measurement Methods. The dynamic torque on the shaft is directly measured by placing a torque sensor or indirectly obtained by attaching a strain gauge. Both methods can only identify the dynamic torque at the sensor location, and some locations do not allow or are inconvenient to install sensors, thus limiting the effectiveness of this method.

[0004] 2. Simulation Calculation Method. First, the external boundary conditions are identified, including force and displacement boundary conditions. Then, a structural model is established using methods such as the finite element method, the external boundary conditions are input, and the dynamic torque on the shaft at different locations is calculated through simulation. This method requires the identification of external boundary conditions; however, external boundary conditions, especially force boundary conditions, are often difficult to identify accurately, which significantly impacts the accuracy of this method. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a dynamic torque identification method that includes a servo drive train. This method is based on modal theory and combines easily measurable structural response to calculate the torque on the shaft. Its modeling is relatively easy and the results are reliable, which can meet the requirements of servo control.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for identifying dynamic torque in a transmission chain includes the following steps: Step 1) Conduct an operational test on the transmission chain mechanism to obtain partial structural responses; Step 2) Calculate the mode shape matrix related to the transmission chain. Based on the mode shape matrix components and structural response at the measurement locations, calculate the overall generalized coordinates of the transmission chain and construct the generalized coordinate matrix. The generalized coordinate calculation method is as follows: ,in for The generalized coordinate vector to be determined at any given time. For the mode shape matrix, Represents a matrix Seek the generalized inverse. for The response vector measured at each time step; the generalized coordinate vectors at different times are arranged in chronological order to form a generalized coordinate matrix; Step 3) Calculate the modal torque at the dynamic torque location to be identified in the transmission chain, and construct the modal torque matrix; Step 4) Calculate the dynamic torque to be identified in the transmission chain based on the generalized coordinate matrix and modal torque matrix at the location of the dynamic torque to be identified; The method for calculating the dynamic torque to be identified in the transmission chain is as follows: ,in For the solution to be found Dynamic torque vector of the transmission chain at all times. The modal torque matrix obtained in step 3) is denoted as .

[0007] Furthermore, the structural response in step 1) is linear acceleration, linear velocity, linear displacement, angular acceleration, angular velocity, or rotation angle; wherein, when the structural response is not a rotation angle, it is converted into the rotation angle of the test position around the axis according to the geometric relationship and integral relationship of the test transmission chain.

[0008] Furthermore, the mode shape matrix mentioned in step 2) is solved by theoretical calculation and finite element software.

[0009] Furthermore, the modal torque mentioned in step 3) is solved by theoretical calculation and finite element software.

[0010] Compared with existing technologies, the beneficial effects of the present invention are as follows: 1. This invention addresses the characteristics of transmission chains by utilizing modal superposition theory to obtain the overall generalized coordinates of the transmission chain, which can identify torques at positions that are inconvenient to measure directly; 2. This invention can utilize various forms of response data, has good adaptability, and has low requirements for response data; 3. The main computational work of this invention involves solving the generalized inverse of a matrix and performing two matrix multiplication operations. The computational workload is low, making it convenient for subsequent application in servo real-time control. 4. This method is applicable to various types of mechanical mechanisms containing transmission chains, and is of great significance for servo debugging and servo control. Attached Figure Description

[0011] Figure 1This is an overall flowchart of the dynamic torque identification method for a transmission chain described in this invention.

[0012] Figure 2 This is a schematic diagram of an antenna structure.

[0013] Figure 3 This is a diagram showing the change in the shaft angle of the transmission chain arm of an antenna elevation mechanism.

[0014] Figure 4 Let be the first-order generalized coordinate of the transmission chain of an antenna elevation mechanism.

[0015] Figure 5 The result is the dynamic torque identification of the motor shaft in the transmission chain of an antenna pitch mechanism. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of this invention are only used to explain this invention and are not intended to limit this invention.

[0017] Example: Taking the pitch drive train of a certain antenna as an example, the specific implementation steps are introduced.

[0018] The overall process of the method described in this invention is as follows: Figure 1 As shown, a method for identifying dynamic torque in a transmission chain includes the following steps: Step 1) Perform an operational test on the transmission chain mechanism to obtain partial structural responses.

[0019] The operational test involves identifying the torque on the shaft during equipment operation, including the transmission chain, while simultaneously measuring the structural response. The structural response can be linear acceleration, linear velocity, linear displacement, angular acceleration, angular velocity, or rotation angle, etc. Specifically, when the structural response is not a rotation angle, it should be converted into the rotation angle around the shaft at the test position based on the geometric and integral relationships of the test transmission chain.

[0020] Antenna structure form such as Figure 2 The antenna reflector 1 and the two side arms 2 are the load components of the transmission chain; the transmission chain mainly includes a reducer and a final-stage elevation reduction gear pair; the power component of the transmission chain is a motor. Sensors are added at the positions of the antenna arms, the reducer output shaft, and the motor shaft to measure changes in shaft angle. The measured response of the antenna arm shaft angle change is as follows: Figure 3 As shown.

[0021] Step 2) Calculate the mode shape matrix related to the transmission chain. Based on the mode shape matrix components and structural response, calculate the overall generalized coordinates of the transmission chain at the dynamic torque position to be identified, and construct the generalized coordinate matrix. The number of elements in the generalized coordinate vector should not be greater than the number of elements in the response vector.

[0022] The aforementioned mode shape matrix can be solved through theoretical calculations and modeling using finite element software or other simulation software. When using theoretical calculations, the transmission chain can be simplified as a multi-degree-of-freedom rotational inertia-torsion spring system, and calculations can be performed based on relevant theories of vibration dynamics. When using finite element analysis or other simulation software for modeling and solving, a model can be established based on the actual geometric dimensions and material parameters of the transmission chain, and modal analysis calculations can be performed. The order of the mode shape matrix should be determined based on the response of the transmission chain under test, and the order of the mode shape matrix should include the order corresponding to the principal vibration of the transmission chain response. The generalized coordinate calculation method is as follows: ,in for The generalized coordinate vector to be determined at any given time. For the mode shape matrix, Represents a matrix Seek the generalized inverse. for The response vector measured at each time step; the generalized coordinate vectors at different times are arranged in chronological order to form a generalized coordinate matrix; Step 3) Calculate the modal torque at the dynamic torque position to be identified in the transmission chain and construct the modal torque matrix.

[0023] This embodiment establishes a finite element simulation model of the antenna based on the antenna drivetrain parameters and antenna structure, and calculates the mode shape matrix as shown in the equation. Each column of the mode shape matrix represents an order, and the elements in each row represent the mode shape matrix components of different orders at the corresponding measurement points. Based on the equation, a generalized coordinate matrix is ​​constructed, with each row corresponding to an order. The first-order generalized coordinate elements are plotted as curves as shown in the equation. Figure 4 .

[0024]

[0025] Step 3) Calculate the modal torque at the dynamic torque position to be identified in the transmission chain and construct the modal torque matrix.

[0026] The modal torque can be solved by theoretical calculations and modeling using finite element software or other simulation software.

[0027] Based on the antenna finite element simulation model in step 2), the modal torque matrix at the motor shaft position is calculated as shown in the formula.

[0028]

[0029] Step 4) Calculate the dynamic torque to be identified in the transmission chain based on the generalized coordinate matrix and modal torque matrix at the location of the dynamic torque to be identified, such as... Figure 5 As shown.

[0030] The method for calculating the dynamic torque to be identified in the transmission chain is as follows: ,in For the solution to be found Dynamic torque vector of the transmission chain at all times. The modal torque matrix obtained in step 3) is... The result obtained in step 2). Generalized coordinates of time.

[0031] In summary, this invention is based on modal superposition theory. It obtains the dynamic response of the shaft angle by testing actual transmission chains, then combines this with the mode shape matrix to obtain generalized coordinates. Finally, it utilizes modal superposition theory, combined with modal torque and generalized coordinates, to obtain the dynamic torque at the location to be identified. This method is easy to implement and can identify the dynamic torque of any shaft in the transmission chain.

[0032] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for identifying dynamic torque in a transmission chain, characterized in that, Includes the following steps: Step 1) Conduct an operational test on the transmission chain mechanism to obtain partial structural responses; Step 2) Calculate the mode shape matrix related to the transmission chain. Based on the mode shape matrix components and structural response at the measurement locations, calculate the overall generalized coordinates of the transmission chain and construct the generalized coordinate matrix. The generalized coordinate calculation method is as follows: ,in for The generalized coordinate vector to be determined at any given time. For the mode shape matrix, Represents a matrix Seek the generalized inverse. for The response vector measured at each time step; the generalized coordinate vectors at different times are arranged in chronological order to form a generalized coordinate matrix; Step 3) Calculate the modal torque at the dynamic torque location to be identified in the transmission chain, and construct the modal torque matrix; Step 4) Calculate the dynamic torque to be identified in the transmission chain based on the generalized coordinate matrix and modal torque matrix at the location of the dynamic torque to be identified; The method for calculating the dynamic torque to be identified in the transmission chain is as follows: ,in For the solution to be found Dynamic torque vector of the transmission chain at all times. The modal torque matrix obtained in step 3) is denoted as .

2. The method for identifying dynamic torque in a transmission chain according to claim 1, characterized in that, The structural response in step 1) is linear acceleration, linear velocity, linear displacement, angular acceleration, angular velocity, or rotation angle; where, when the structural response is not a rotation angle, it is converted into the rotation angle of the test position around the axis according to the geometric relationship and integral relationship of the test transmission chain.

3. The method for identifying dynamic torque in a transmission chain according to claim 1, characterized in that, The mode shape matrix mentioned in step 2) is solved by theoretical calculation and finite element software.

4. The method for identifying dynamic torque in a transmission chain according to claim 1, characterized in that, The modal torque mentioned in step 3) is solved by theoretical calculation and finite element software.

Images