Spatial extrapolation method for temperature test data of electric tools outside the space station

Abstract

The present invention discloses a spatial extrapolation method for temperature test data of an electric tool outside a space station cabin, comprising the following steps: step 1: determining the position coordinates of each temperature measuring point; step 2: obtaining the temperature test data of each measuring point; step 3: completing finite element simulation to obtain thermal simulation data of the entire finite element model; step 4: calculating the temperature simulation error at each measuring point; step 5: determining the weight function of each measuring point; step 6: calculating the distance between any node on the finite element model of the electric tool and each measuring point; step 7: calculating the temperature extrapolation result of any node on the finite element model of the electric tool; step 8: obtaining the temperature extrapolation results of all nodes on the finite element model of the electric tool. The present invention integrates temperature simulation data and temperature measuring point test data to realize spatial extrapolation of temperature test data on the entire finite element model, and has significant advantages such as a small number of temperature measuring points required, a small spatial extrapolation error, a three-dimensional extrapolation result and no spatial blind spots.

Description

Technical Field

[0001] The present invention belongs to the field of interdisciplinary technology of aerospace and testing. Specifically, the present invention mainly relates to a method for spatial extrapolation of temperature test data of electric tools outside a space station by integrating simulation data. Background Art

[0002] The space station's extravehicular power tools are a type of space station's extravehicular maintenance tools. They are used to assist astronauts in carrying out equipment replacement and maintenance work while wearing space suits on orbit. They are very important for the long-term stable operation of the space station. China's space station's extravehicular power tools (hereinafter referred to as power tools) consist of four parts: battery components (lithium batteries), motor components (including reducers), control circuits (i.e., electronic control units), housings, and extension rods. They can adapt to the complex vacuum and high and low temperature environments outside the space station, have fixed torque tightening and loosening working modes, and are equipped with a sleep mode. The realization of these working modes and functions of power tools is very sensitive to temperature. For example, the suitable working temperature range of the battery component is 0℃~40℃, while the motor component may have difficulty starting at low temperatures and may have poor performance at high temperatures. Therefore, it is very necessary to accurately and comprehensively monitor the temperature of power tools.

[0003] The temperature measurement points of electric tools are generally distributed on the motor, reducer, and battery. The number is very limited, generally not more than 10. When conducting thermal vacuum tests on the ground, some temperature measurement points can be temporarily added, but they are still spatially discretely distributed, which is not enough to fully grasp the temperature distribution state of the electric tool. The finite element simulation method can be used to comprehensively and intuitively obtain the three-dimensional temperature field of the electric tool, but due to the complex structure of the electric tool and the complex thermal environment it faces, the error of the temperature simulation data is often large. In summary, a temperature field acquisition method that can have both the accuracy of temperature test data and the spatial integrity of temperature simulation data is proposed, thereby realizing the spatial extrapolation of temperature test data. It is very important for accurately and comprehensively grasping the health status of electric tools, and it is also one of the important industry problems.

[0004] The main difficulty in realizing spatial extrapolation of power tool temperature test data lies in how to reasonably integrate simulation data and test data while retaining the advantages of both data. Summary of the invention

[0005] The purpose of the present invention is to provide a method for spatial extrapolation of temperature test data of electric tools outside the space station, and to obtain temperature data of all nodes of a finite element model with a smaller error. The core of the present invention is how to fuse temperature simulation data and test data of a small number of temperature measurement points to achieve spatial extrapolation of test data on the entire finite element model.

[0006] The present invention adopts the following technical solution:

[0007] refer toFigure 1 The steps of the spatial extrapolation method of the temperature test data of the space station's extravehicular power tools are as follows:

[0008] Step 1, determine the position coordinates of each temperature measurement point;

[0009] The position coordinates of N temperature measurement points are recorded as (x I ,y I ,z I )、(x II ,y II ,z II ),……(x θ ,y θ ,z θ ),……(x N ,y N ,z N ), where N is a positive integer.

[0010] Step 2, obtaining temperature test data of each measuring point;

[0011] The temperature test data of N measuring points are recorded as T I , T II ,……T θ ,……T N .

[0012] Step 3, completing finite element simulation to obtain thermal simulation data of the entire power tool finite element model;

[0013] Considering the heat consumption and thermal boundary conditions of the battery and motor in the power tool, the material characteristic parameters of each component and part are input, and the finite element model of the power tool is established. The thermal simulation data of the entire finite element model of the power tool is obtained by finite element method calculation. That is, the temperature simulation data of n nodes of the finite element model is obtained, which is recorded as T 1 ′、T 2 ', ...T k ', ...T n ′, and the simulation data at N temperature measurement points, denoted as T I ′、T′ II , ...T′ θ , ...T′ N .

[0014] This step is a commonly used method in the industry. The specific process can be found in references [201711232421, Simulation method and device for motor temperature field] and [201810340791, A thermal analysis method for switched reluctance motor based on variable density symmetric grid division], which will not be elaborated here.

[0015] Step 4, calculating the temperature simulation error at each measuring point;

[0016] The temperature simulation errors of N temperature measurement points are recorded as e I 、e II ,……e θ ,……e N , the calculation formula is T I -T′ II , T II -T′ II ,……T θ -T′ θ ,……T N -T′ N .

[0017] Step 5, determine the weight function of each measuring point;

[0018] The weight functions of the N temperature measurement points are recorded as a(ρ), b(ρ)...θ(ρ),...N(ρ), and the independent variable ρ refers to the distance from each temperature measurement point. The weight function needs to meet the requirement of monotonically decreasing as the independent variable ρ increases.

[0019] Step 6, calculating the distance between any node on the finite element model of the electric tool and each measuring point;

[0020] The coordinates of any node k on the finite element model of the power tool are (x k ,y k ,z k ), then the distance between the node k and any measuring point θ is

[0021] Step 7, calculating the temperature extrapolation result of any node on the finite element model of the power tool;

[0022] The temperature extrapolation result T of any node k on the finite element model of the power tool k From the simulation result T at node k k ′ and the weighted sum of the temperature simulation errors of the two temperature measurement points closest to node k. Taking the two nearest temperature measurement points I and II as an example, T k The expression is:

[0023] T k =T′ k +a(ρ Ik ) I +b(ρ IIk ) II

[0024] In the formula, ρ Ik and ρ IIk are the distances from node k to temperature measurement points I and II respectively.

[0025] Step 8, obtaining the temperature extrapolation results of all nodes on the power tool finite element model.

[0026] Use the method in step 7 to calculate the temperature extrapolation results T of all nodes 1 , T 2 ,……T k ,……T n .

[0027] At this point, the spatial extrapolation of the power tool temperature test data is completed.

[0028] The temperature test data in step 2 may be single test data or an average value of multiple test data.

[0029] The two most recent temperature measurement points in step 7 may also be one or more.

[0030] Among them, all the nodes described in step 8 may also be partial nodes.

[0031] Among them, the spatial extrapolation method of the temperature test data of the space station's extravehicular power tools can also be used only for the housing components, motor components and battery components of the power tools.

[0032] Compared with the prior art, the present invention has the following outstanding substantive features and significant advantages:

[0033] The present invention integrates temperature simulation data and temperature measurement point test data, and realizes the spatial extrapolation of temperature test data on the entire finite element model. It has the significant advantages of requiring a small number of temperature measurement points, small spatial extrapolation error, three-dimensional extrapolation results and no spatial blind spots. It is very suitable for conducting ground tests and on-orbit health status monitoring of space station extravehicular power tools in a fast, efficient and economical manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is an implementation flow chart of the method involved in this application;

[0035] Figure 2 It is a schematic diagram of the temperature measurement points and extrapolation points for the complete electric tool outside the space station;

[0036] Figure 3 is a schematic diagram of the weight function;

[0037] Figure 4 This is a schematic diagram of the temperature measurement points and extrapolation points for the battery of the space station's extravehicular power tools;

[0038] Figure 5 This is a schematic diagram of the temperature measurement points and extrapolation points for the motor of the space station's extravehicular power tools. DETAILED DESCRIPTION

[0039] The principles, steps and features of the present invention are further described below in conjunction with the accompanying drawings.

[0040] Implementation 1:

[0041] refer to Figure 1 , Figure 2 and Figure 3 The steps for carrying out the spatial extrapolation of temperature test data using the space station extravehicular power tool as the object are as follows:

[0042] Step 1, determine the position coordinates of each temperature measurement point;

[0043] The position coordinates of the two temperature measurement points are recorded as (x I ,y I ,z I )、(x II ,y II ,z II ).

[0044] Step 2, obtaining temperature test data of each measuring point;

[0045] The temperature test data of the two measuring points are recorded as T I , T II .

[0046] Step 3, completing finite element simulation to obtain thermal simulation data of the entire power tool finite element model;

[0047] Considering the heat consumption and thermal boundary conditions of the battery and motor in the power tool, the material characteristic parameters of each component and part are input, and the finite element model of the power tool is established. The thermal simulation data of the entire finite element model of the power tool is obtained by finite element method calculation. That is, the temperature simulation data of n nodes of the finite element model is obtained, which is recorded as T 1 ′、T 2 ', ...T k ', ...T n ′, and the simulation data at two temperature measurement points, denoted as T I ′、T′ II .

[0048] This step is a commonly used method in the industry. The specific process can be found in references [201711232421, Simulation method and device for motor temperature field] and [201810340791, A thermal analysis method for switched reluctance motor based on variable density symmetric grid division], which will not be elaborated here.

[0049] Step 4, calculating the temperature simulation error at each measuring point;

[0050] The temperature simulation errors of the two temperature measurement points are recorded as e I 、e II, the calculation formula is T I -T′ II , T II -T′ II .

[0051] Step 5, determine the weight function of each measuring point;

[0052] The weight functions of the two temperature measurement points are respectively recorded as a(ρ Ik ), b(ρ IIk ), ρ Ik Refers to the distance between node k and temperature measurement point I, ρ IIk Refers to the distance between node k and temperature measurement point II. The weight function is the sigmoid function, and the expression is:

[0053]

[0054]

[0055] Step 6, calculating the distance between any node on the finite element model of the electric tool and each measuring point;

[0056] The coordinates of any node k on the finite element model of the power tool are (x k ,y k ,z k ), then the distances between the node k and the measuring points I and II are and

[0057] Step 7, calculating the temperature extrapolation result of any node on the finite element model of the power tool;

[0058] The temperature extrapolation result T of any node k on the finite element model of the power tool k From the simulation result T′ at node k k The weighted sum of the temperature simulation errors of the two temperature measurement points I and II is obtained as follows:

[0059] T k =T′ k +a(ρ Ik ) I +b(ρ IIk ) II

[0060] Step 8, obtaining the temperature extrapolation results of all nodes on the power tool finite element model.

[0061] Use the method in step 7 to calculate the temperature extrapolation results T of all nodes 1 , T 2 ,……T k ,……T n .

[0062] At this point, the spatial extrapolation of the power tool temperature test data is completed.

[0063] Implementation 2:

[0064] refer to Figure 1 , Figure 3 and Figure 4 The steps for carrying out the spatial extrapolation of temperature test data using the space station extravehicular power tool battery assembly as the object are as follows:

[0065] Step 1, determine the position coordinates of each temperature measurement point;

[0066] The position coordinates of the two temperature measurement points are recorded as (x I ,y I ,z I )、(x II ,y II ,z II ).

[0067] Step 2, obtaining temperature test data of each measuring point;

[0068] The average values ​​of multiple temperature test data at two measuring points are recorded as T I , T II .

[0069] Step 3, completing finite element simulation to obtain thermal simulation data of the entire battery assembly finite element model;

[0070] Considering the heat consumption and thermal boundary conditions of the battery assembly, the material characteristic parameters of each part are input, and the finite element model of the battery assembly is established. The thermal simulation data of the finite element model of the entire battery assembly is obtained by finite element method. That is, the temperature simulation data of n nodes of the finite element model is obtained, which is recorded as T 1 ′、T 2 ', ...T k ', ...T n ′, and the simulation data at two temperature measurement points, denoted as T I ′、T′ II .

[0071] This step is a commonly used method in the industry. The specific process can be found in references [201711232421, Simulation method and device for motor temperature field] and [201810340791, A thermal analysis method for switched reluctance motor based on variable density symmetric grid division], which will not be elaborated here.

[0072] Step 4, calculating the temperature simulation error at each measuring point;

[0073] The temperature simulation errors of the two temperature measurement points are recorded as e I、e II , the calculation formula is T I -T′ II , T II -T′ II .

[0074] Step 5, determine the weight function of each measuring point;

[0075] The weight functions of the two temperature measurement points are respectively recorded as a(ρ Ik ), b(ρ IIk ), ρ Ik Refers to the distance between node k and temperature measurement point I, ρ IIk Refers to the distance between node k and temperature measurement point II. The weight function is the sigmoid function, and the expression is:

[0076]

[0077]

[0078] Step 6, calculating the distance between any node on the battery assembly finite element model and each measuring point;

[0079] The coordinates of any node k on the battery assembly finite element model are (x k ,y k ,z k ), then the distances between the node k and the measuring points I and II are and

[0080] Step 7, calculating the temperature extrapolation result of any node on the battery assembly finite element model;

[0081] The temperature extrapolation result T of any node k on the battery assembly finite element model k From the simulation result T′ at node k k The weighted sum of the temperature simulation errors of the two temperature measurement points I and II is obtained as follows:

[0082] T k =T′ k +a(ρ Ik ) I +b(ρ IIk ) II

[0083] Step 8, obtain the temperature extrapolation results of all nodes on the battery component finite element model.

[0084] Use the method in step 7 to calculate the temperature extrapolation results T of all nodes 1 , T 2 ,……T k ,……Tn .

[0085] At this point, the spatial extrapolation of the temperature test data of the space station's extravehicular power tool battery components has been completed.

[0086] Implementation 3:

[0087] refer to Figure 1 , Figure 3 and Figure 4 The steps for carrying out the spatial extrapolation of temperature test data using the motor assembly of the space station's extravehicular power tool are as follows:

[0088] Step 1, determine the position coordinates of each temperature measurement point;

[0089] The position coordinates of the two temperature measurement points are recorded as (x I ,y I ,z I )、(x II ,y II ,z II ).

[0090] Step 2, obtaining temperature test data of each measuring point;

[0091] The average values ​​of multiple temperature test data at two measuring points are recorded as T I , T II .

[0092] Step 3, completing finite element simulation to obtain thermal simulation data of the finite element model of the entire motor assembly;

[0093] Considering the heat loss and thermal boundary conditions of the motor assembly, the material characteristic parameters of each part are input, and the finite element model of the motor assembly is established. The thermal simulation data of the finite element model of the entire motor assembly is obtained by finite element method. That is, the temperature simulation data of n nodes of the finite element model is obtained, which is recorded as T 1 ′、T 2 ', ...T k ', ...T n ′, and the simulation data at two temperature measurement points, denoted as T I ′、T′ II .

[0094] This step is a commonly used method in the industry. The specific process can be found in references [201711232421, Simulation method and device for motor temperature field] and [201810340791, A thermal analysis method for switched reluctance motor based on variable density symmetric grid division], which will not be elaborated here.

[0095] Step 4, calculating the temperature simulation error at each measuring point;

[0096] The temperature simulation errors of the two temperature measurement points are recorded as e I 、e II , the calculation formula is T I -T′ II , T II -T′ II .

[0097] Step 5, determine the weight function of each measuring point;

[0098] The weight functions of the two temperature measurement points are respectively recorded as a(ρ Ik ), b(ρ IIk ), ρ Ik Refers to the distance between node k and temperature measurement point I, ρ IIk Refers to the distance between node k and temperature measurement point II. The weight function is the sigmoid function, and the expression is:

[0099]

[0100]

[0101] Step 6, calculating the distance between any node on the finite element model of the motor component and each measuring point;

[0102] The coordinates of any node k on the finite element model of the motor component are (x k ,y k ,z k ), then the distances between the node k and the measuring points I and II are and

[0103] Step 7, calculating the temperature extrapolation result of any node on the finite element model of the motor component;

[0104] The temperature extrapolation result T of any node k on the finite element model of the motor component k From the simulation result T′ at node k k The weighted sum of the temperature simulation errors of the two temperature measurement points I and II is obtained as follows:

[0105] T k =T′ k +a(ρ Ik ) I +b(ρ IIk ) II

[0106] Step 8, obtaining the temperature extrapolation results of all nodes on the finite element model of the motor component.

[0107] Use the method in step 7 to calculate the temperature extrapolation results T of all nodes 1 , T2 ,……T k ,……T n .

[0108] At this point, the spatial extrapolation of the temperature test data of the motor components of the space station's extravehicular power tools has been completed.

[0109] Although the specific embodiments of the present invention are described and illustrated in detail above, it should be pointed out that various equivalent changes and modifications can be made to the above embodiments based on the concept of the present invention. As long as the functional effects produced do not exceed the spirit covered by the specification and drawings, they should all be within the protection scope of the present invention.

Claims

1. A spatial extrapolation method for temperature test data of an extravehicular electric tool of a space station, comprising: Step 1: Determine the position coordinates of each temperature measurement point, and record the position coordinates of N temperature measurement points as (x I ,y I ,z I )、(x II ,y II ,z II ),……(x θ ,y θ ,z θ ),……(x N ,y N ,z N ), wherein N is a positive integer; Step 2: Obtain the temperature test data of each temperature measuring point. The temperature test data of the N temperature measuring points are respectively recorded as T I , T II ,……T θ ,……T N ; Step 3, complete the finite element simulation to obtain the thermal simulation data of the entire power tool finite element model, consider the heat consumption and thermal boundary conditions of the battery and motor in the power tool, input the material characteristic parameters of each component and part, establish the finite element model of the power tool, and calculate the thermal simulation data of the entire power tool finite element model through the finite element method, that is, obtain the temperature simulation data of n nodes of the finite element model, recorded as T1′, T2′, ... T k ', ...T n ′, and the simulation data at the N temperature measurement points, denoted as T I ′、T II ', ...T θ ', ...T N ′; Step 4: Calculate the temperature simulation error at each measuring point. The temperature simulation errors of the N temperature measuring points are recorded as e I 、e II ,……e θ ,……e N , the calculation formula is T I -T I ′、T II -T II ', ...T θ -T θ ', ...T N -T N ′; Step 5, determine the weight function of each measuring point, the weight functions of the N temperature measuring points are respectively recorded as a(ρ), b(ρ)...θ(ρ),...N(ρ), where the independent variable ρ refers to the distance from each temperature measuring point, and the weight function needs to satisfy the independent variable ρ increasing and monotonically decreasing requirements; Step 6, calculate the distance between any node on the finite element model of the electric tool and each of the temperature measurement points, and record the coordinates of any node k on the finite element model of the electric tool as (x k ,y k ,z k ), then the distance between the node k and any of the temperature measurement points θ is Step 7, calculate the temperature extrapolation result of any node on the finite element model of the power tool, the temperature extrapolation result T of any node k on the finite element model of the power tool k From the simulation result T at node k k ′ is obtained by weighted summing of the temperature simulation errors of the two temperature measurement points closest to the node k. Taking the two nearest temperature measurement points I and II as an example, T k The expression is: T k =T k ′+a(ρ Ik )e I +b(r IIk )e II In the formula, ρ Ik and ρ IIk are the distances from node k to temperature measurement points I and II respectively; Step 8, obtaining the temperature extrapolation results of all nodes on the finite element model of the electric tool, using the method of step 7 to calculate the temperature extrapolation results T1, T2, ... T of all nodes k ,……T n .

2. The spatial extrapolation method of temperature test data of space station extravehicular power tools according to claim 1 is characterized in that: In step 2, the temperature test data may be single test data or an average value of multiple test data.

3. The spatial extrapolation method of temperature test data of space station extravehicular power tools according to claim 1 is characterized in that: The two nearest temperature measurement points in step 7 may also be one or more.

4. The spatial extrapolation method for temperature test data of an extravehicular power tool of a space station according to any one of claims 1 to 3, characterized in that: The spatial extrapolation method may also be applied only to the housing assembly, motor assembly and battery assembly of the electric tool.

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