Test device and method for testing the relaxation of shape memory alloy microwires

Abstract

The embodiment of the present application discloses a test device for testing the relaxation of shape memory alloy microwires, and the test device includes a fixture, a motion component, a sensing unit and a first sensor. The fixture is used to fix and clamp the shape memory alloy microwire. The motion component is fixedly connected to the fixture, and is used to drive the fixture to move under the drive of the motor controller. The sensing unit includes at least two sensing members, and the shape memory alloy microwire is arranged between the two sensing members. When the fixture moves, the shape memory alloy microwire contacts the sensing member and deforms. The first sensor is connected to the sensing unit, and is used to measure the force applied to the shape memory alloy microwire when it is deformed, and transmits the measured data to the terminal device to calculate the relaxation of the shape memory alloy microwire. The embodiment of the present application also provides a test method for testing the relaxation of shape memory alloy microwires. The embodiment of the present application can effectively improve the test accuracy, improve the test efficiency and is easy to use.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of testing technology, and in particular to a testing device and method for testing the relaxation of shape memory alloy microwires. Background Art

[0002] Shape memory alloy (SMA) motors usually use metal terminals and shape memory alloy microwires as actuators. The general SMA microwire remains in a relaxed state in the metal terminal, that is, there is no pulling force or tension inside the shape memory alloy microwire. In existing processing technology, the shape memory alloy microwire can be processed in the middle of the metal terminal and remain in a relaxed state. A small amount of processing error will have a significant impact on the performance of the shape memory alloy motor, so accurate relaxation testing methods are of great significance.

[0003] An existing relaxation test technology is Figure 1 As shown in , in the test frame, the fixing seat is connected to the first end of the constant current source through a lead, the fixing seat is connected to the second end of the constant current source through a lead, and the microwire is connected between the two fixing seats. This method mainly judges the actual length of the shape memory alloy microwire based on the expression of resistance. The actual resistance value of the shape memory alloy microwire is proportional to the resistivity, and its length is inversely proportional to the cross-sectional area. If the resistivity and the cross-sectional area do not change, then the length and the resistance value are in a linear proportional relationship. Thus, the length at this time can be tested. However, in the process of implementing this application, the inventor found that the above-mentioned test method has at least the following problems: in actual testing, the resistivity and the cross-sectional area will change due to temperature and memory alloy strain, and the relaxation cannot be accurately measured. In addition, using the resistance test method for testing will encounter contact problems between the probe and the microwire, which will affect the accuracy of the relaxation test. Summary of the invention

[0004] The embodiments of the present application provide a testing device and method for testing the relaxation of shape memory alloy microwires. By adopting the embodiments of the present application, the testing accuracy can be effectively improved, and the testing efficiency can be improved. The testing device is small in size and easy to use.

[0005] In a first aspect, an embodiment of the present application provides a testing device for testing the relaxation of a shape memory alloy microwire, the testing device comprising a jig, a moving component, a sensing unit and a first sensor; the jig is used to fix and clamp the shape memory alloy microwire; the moving component is fixedly connected to the jig, and is used to drive the jig to move under the drive of a motor controller; the sensing unit comprises at least two sensing members, and the shape memory alloy microwire is arranged between the at least two sensing members; when the jig moves, the shape memory alloy microwire contacts the sensing member and deforms; the first sensor is fixedly connected to the sensing unit, and is used to measure the force acting on the shape memory alloy microwire during deformation, and transmit the measured data to a terminal device to calculate the relaxation of the shape memory alloy microwire.

[0006] The embodiments of the present application can solve the problem that the existing testing technology cannot accurately measure the slack. The embodiments of the present application can effectively improve the test accuracy and the test efficiency. The test device is small in size and easy to use.

[0007] In combination with the first aspect, in a possible design, the jig includes a first protrusion and a second protrusion, and two ends of the shape memory alloy microwire are fixedly connected to the first protrusion and the second protrusion respectively. Based on such a design, the shape memory alloy microwire can be loaded and fixed on the jig, which is conducive to improving the test accuracy of the microwire relaxation.

[0008] In combination with the first aspect, in a possible design, the center point between the two sensing elements is connected to the center point of the shape memory alloy microwire. Based on such a design, aligning the center point of the sensing unit with the center point of the shape memory alloy microwire is conducive to improving the test accuracy of the microwire relaxation.

[0009] In combination with the first aspect, in a possible design, the sensing member is provided with a groove, and when the shape memory alloy microwire contacts the sensing member, the shape memory alloy microwire is held in the groove. Based on such a design, the position displacement of the shape memory alloy microwire under the action of tension is avoided, thereby affecting the accuracy of the test of the microwire relaxation.

[0010] In combination with the first aspect, in a possible design, the testing device further includes a first display instrument, the first sensor is connected to the first display instrument via a cable, and the first display instrument is used to display the value of the force measured by the first sensor. Based on such a design, the value of the force measured by the first sensor can be monitored in real time through the display instrument, which is convenient for users.

[0011] In combination with the first aspect, in a possible design, the testing device further includes a first frame, and the first frame is used to fix the first sensor. Based on such a design, the first sensor can be made more stable, which is conducive to improving the test accuracy of the microfilament relaxation.

[0012] In combination with the first aspect, in a possible design, the test device further includes a calibration block, which is used to calibrate the relative position of the first frame and the motion component; the test device further includes a second sensor, which is used to sense the displacement of the fixture and transmit the sensed displacement of the fixture to a terminal device. Based on such a design, it is helpful to improve the test accuracy of the microwire relaxation.

[0013] In combination with the first aspect, in a possible design, the test device further includes a bearing plate and a shockproof base, the bearing plate is used to bear the first frame, the motion component and the first display instrument, and the shockproof base is used to suppress vibration. Based on such a design, it is helpful to improve the test accuracy of the microfilament relaxation.

[0014] In a second aspect, the present application also provides a test method for testing the relaxation of shape memory alloy microwires, the test method comprising the following steps:

[0015] The shape memory alloy microwire is fixedly clamped on the fixture;

[0016] The jig is driven to move under the drive of the motor controller;

[0017] The shape memory alloy microwire is arranged between at least two sensing elements; when the jig moves, the shape memory alloy microwire contacts the sensing elements and deforms;

[0018] The force applied to the shape memory alloy microwire during deformation is measured, and the measured data is transmitted to a terminal device to calculate the relaxation of the shape memory alloy microwire.

[0019] The embodiments of the present application can solve the problem that the existing testing technology cannot accurately measure the slack. The embodiments of the present application can effectively improve the test accuracy and the test efficiency. The test device is small in size and easy to use.

[0020] In conjunction with the second aspect, in a possible design, the test method further includes: fixing the two ends of the shape memory alloy microwire to the first protrusion and the second protrusion on the fixture respectively. Based on such a design, the shape memory alloy microwire can be loaded and fixed on the fixture, which is conducive to improving the test accuracy of the microwire relaxation.

[0021] In conjunction with the second aspect, in a possible design, the test method further includes: docking the center point between the two sensing elements with the center point of the shape memory alloy microwire. Based on such a design, aligning the center point of the sensing unit with the center point of the shape memory alloy microwire is conducive to improving the test accuracy of the microwire relaxation.

[0022] In combination with the second aspect, in a possible design, the test method further includes: when the shape memory alloy microwire contacts the sensing element, the shape memory alloy microwire is clamped in a groove of the sensing element. Based on such a design, the shape memory alloy microwire is prevented from being displaced under the action of tension, thereby affecting the accuracy of the test of the microwire relaxation.

[0023] In combination with the second aspect, in a possible design, the test method further includes: the motion component drives the fixture to rotate; wherein the rotation speed of the fixture is lower than a preset value. Based on such a design, the shape memory alloy microwire is prevented from breaking under the action of a faster rotation speed and a larger pulling force, thereby protecting the shape memory alloy microwire.

[0024] The test device and method provided in the embodiment of the present application are performed by fixing and clamping the shape memory alloy microwire on the fixture. The shape memory alloy microwire is brought into contact with at least two sensing members and deformed by controlling the rotation of the fixture. The force applied to the shape memory alloy microwire during deformation is then measured by the first sensor, and the measured data is transmitted to the terminal device to calculate the relaxation of the shape memory alloy microwire. The test device and method provided in the embodiment of the present application can effectively improve the test accuracy, improve the test efficiency, and the test device is small in size and easy to use. By adopting the embodiment of the present application, the test accuracy can be effectively improved, the test efficiency can be improved, and the test device is small in size and easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The invention is a testing device in the prior art for testing the relaxation of shape memory alloy microwires.

[0026] Figure 2 It is a schematic diagram of the connection of shape memory alloy microwires in an embodiment of the present application.

[0027] Figure 3 It is an application scenario diagram of the test device in the embodiment of the present application.

[0028] Figure 4 It is a functional module diagram of the testing device in the embodiment of the present application.

[0029] Figure 5 It is a schematic diagram of the structure of the test device in the embodiment of the present application.

[0030] Figure 6 It is another structural schematic diagram of the testing device in the embodiment of the present application.

[0031] Figure 7 It is another structural schematic diagram of the testing device in the embodiment of the present application.

[0032] Figure 8a-8c This is a state diagram of placing a shape memory alloy microwire on a fixture for testing in an embodiment of the present application.

[0033] Fig. 9 4 is a graph showing the relationship between the rotation angle and torque of the shape memory alloy microwire described in the embodiment of the present application.

[0034] Fig.10 4 is a graph showing the relationship between the rotation angle and torque of the shape memory alloy microwire in the embodiment of the present application.

[0035] Fig.11 It is a flow chart of the testing method in the embodiment of the present application.

[0036] Main component symbols

[0037] Test device 100

[0038] Terminal device 102

[0039] Control device 104

[0040] Object under test 106

[0041] Test Unit 1

[0042] Front Window 2

[0043] Door lock 4

[0044] Armrest 5

[0045] Base 6

[0046] Dual working button 7

[0047] Frame 8

[0048] Vision System 11

[0049] First sensor 12

[0050] First display instrument 13

[0051] Second display instrument 14

[0052] The first motion component 15

[0053] The second motion component 16

[0054] First rack 17

[0055] Second rack 18

[0056] Earthquake-resistant base 19

[0057] Jig 20

[0058] Second sensor 21

[0059] Loading plate 22

[0060] Sensing unit 23

[0061] Sensor 231

[0062] Groove 232

[0063] Bump 201

[0064] Terminal 202

[0065] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0067] In the description of this specification, unless otherwise specified, "plurality" means two or more. In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. The terms "include", "comprise", "have" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0068] An embodiment of the present application provides a testing device for testing the relaxation of shape memory alloy (SMA) microwires. The testing device can be applied to the relevant testing technology field of shape memory alloy motors, and can effectively improve the testing accuracy and testing efficiency. The testing device is small in size and easy to use.

[0069] A testing device for testing the relaxation of shape memory alloy microwires disclosed in the embodiments of the present application can obtain accurate relaxation values ​​of shape memory alloy microwires in a relatively short testing time.

[0070] It will be appreciated that, in one embodiment, slack may be defined as the difference between the actual length of the microfilament and the distance between the two terminals.

[0071] Specifically, see Figure 2 , which can further illustrate the definition of the relaxation of SMA filaments. Figure 2 The △L described in the figure can be used as the definition of relaxation in this article. In the design process, the relaxation parameter can affect some control performances of the controller, such as control accuracy. Therefore, the precise control and testing of the relaxation of SMA microwires is of great significance.

[0072] See also Figure 3 , Figure 3 is a structural diagram of a test system that can be applied in the embodiment of the present application. Figure 3 As shown, the test system may include a test device 100, a terminal device 102, a control device 104 and an object to be tested 106. The terminal device 102 may be a user equipment (UE), for example, a mobile phone, a tablet computer (Tablet Personal Computer), a laptop computer (Laptop Computer), a personal digital assistant (Personal Digital Assistant, referred to as PDA), a mobile Internet device (Mobile Internet Device, MID), a wearable device (Wearable Device) or a personal computer (Personal Computer, PC) and other terminal side devices. It should be noted that the specific type of the terminal device 102 is not limited in the embodiments of the present application.

[0073] Specifically, the test device 100 is connected to the control device 104 via an RS232 bus, an RS485 bus or a network cable. The terminal device 102 can also be connected to the control device 104 via an RS232 bus, an RS485 bus or a network cable. The object to be tested 106 can be loaded into the test device 100 or taken out of the test device 100.

[0074] In the specific implementation process, the control device 104 performs hardware control on the test device 100, the test device 100 can feed back test data to the control device 104, the terminal device 102 can perform algorithm control on the control device 104, and the control device 104 can transmit data back to the terminal device 102 for display.

[0075] In an embodiment of the present application, the terminal device 102 can perform the above-mentioned analysis and processing functions by configuring at least one processor and at least one memory, wherein the memory can be used to store software programs and modules, and the processor executes various application functions and data processing of the terminal device by running the software programs and modules stored in the memory.

[0076] It can be understood that the “objects to be tested” mentioned in the embodiments of the present application can all be shape memory alloy microwires.

[0077] See also Figure 4 , through the coordination of software, hardware and related steps, the precise test of the relaxation of SMA microfilaments can be achieved.

[0078] like Figure 4 As shown, in a specific embodiment, the terminal device 102 may be installed with a main control software. Specifically, the main control software may implement functions including visual detection function, test control function, test algorithm function, data analysis function, and the like.

[0079] It is understood that each function of the above software part can be executed by the corresponding hardware part. Specifically, in some embodiments, the visual inspection function can be implemented by a visual system and a test fixture, and can be executed under the loading step of the test system.

[0080] The test control function can be realized by the operating mechanism and the force sensor, and can be executed under the test control step of the test system.

[0081] The test algorithm function can be implemented by the terminal device and the control device, and can be executed under the software calculation steps of the test system.

[0082] The data analysis function can be implemented by the display and can also be performed under the data presentation step of the test system.

[0083] The motion control function can be realized by the motion mechanism and can be executed under the unloading step of the test system.

[0084] See also Figure 5 , showing a schematic diagram of a testing device 100 for testing the relaxation of shape memory alloy microwires of the present application.

[0085] In this embodiment, the testing device 100 may include a testing unit 1 , a front window 2 , a door lock 4 , an armrest 5 , a base 6 , a dual working button 7 , and an outer frame 8 .

[0086] In a specific implementation process, the front window 2 may be a window that can be flipped up and down, and the front window 2 is arranged at the end of the outer frame 8 .

[0087] Therefore, in the embodiment of the present application, the object to be tested 106, the test unit 1 or other hardware can be taken out or put in by opening and closing the front window 2. That is, when the front window 2 is opened, the object to be tested 106, the test unit 1 or other hardware can be taken out from the outer frame 8, or the object to be tested 106, the test unit 1 or other hardware can be put into the outer frame 8.

[0088] It can be understood that, in one embodiment, the front window 2 can be made of a transparent material, so when the object to be tested 106 is tested, the movement of the hardware can be observed in real time.

[0089] In one embodiment, the test unit 1 can be used to monitor, move or test the object to be tested 106. The test device 100 can also include three-sided sheet metal (not shown). The three-sided sheet metal can be used to mount some electrical components.

[0090] Therefore, the testing device 100 in the embodiment of the present application can be easily maintained, and the purpose of integrating and miniaturizing the testing device 100 can also be achieved.

[0091] In one embodiment, the door lock 4 and the handrail 5 are arranged on one side of the outer frame 8, and the door lock 4, the handrail 5 and the base 6 can also be basic components of the outer frame.

[0092] In the embodiment of the present application, the door lock 4 and the handrail 5 can be used to facilitate the assembly, maintenance and transportation of the testing device.

[0093] In one embodiment, the dual working button 7 can be used to start the testing device 100 and enable the testing device 100 to enter a testing working state.

[0094] See also Figure 6 , is a schematic diagram of the structure of the test unit 1 in the embodiment of the present application. Figure 6 As shown, in one embodiment, the test unit 1 may include a visual system 11 , a first sensor 12 , and a first display instrument 13 .

[0095] In the specific implementation process, the visual system 11 is electrically connected to the terminal device 102 via a cable (not shown in the figure). Therefore, the image captured by the visual system 11 in the embodiment of the present application can be displayed through the terminal device 102, and the user can view the test-related results through the displayed image.

[0096] In one embodiment, the object to be measured 106 can be an SMA microwire, and the first sensor 12 can measure the force applied to the SMA microwire when it is stretched or contracted. The first sensor 12 is electrically connected to the first display instrument 13 via a cable (not shown).

[0097] Therefore, the first display instrument 13 can display the force value measured by the first sensor 12. It can be understood that the first sensor 12 can feed back the test data to the control device 104 after measuring the force data of the SMA microwire.

[0098] In some embodiments, the test unit 1 may further include a second display instrument 14 , a first motion assembly 15 , a second motion assembly 16 , a first frame 17 , a second frame 18 , a seismic base 19 and a bearing plate 22 .

[0099] In the embodiment of the present application, the second display instrument 14 can be electrically connected to a testing instrument (not shown in the figure) through a cable.

[0100] It is understandable that the test instrument can be used to test the displacement value of the test unit 1 in the first direction (such as the Z direction in the three-dimensional coordinate system). The second display instrument 14 can display the displacement value of the test unit 1 in the Z direction. Therefore, the user can view the displacement of the test unit 1 in the Z direction through the second display instrument 14.

[0101] The first motion component 15 and the second motion component 16 are both connected to a motor controller (not shown in the figure). In one embodiment, the first motion component 15 and the second motion component 16 can be adjusted by the motor controller to adjust the position of the platform in four degrees of freedom XYZθ. It can be understood that the first motion component 15 can be used to adjust the position of the test unit 1 in the XY plane, and the second motion component 16 can be used to adjust the position of the test unit 1 in the Zθ plane. Wherein, θ is a rotation around the Z axis in the XY plane.

[0102] As an example in the present application, the first frame 17 may be used to fix the first sensor 12 , and the second frame 18 may be used to fix the vision system 11 .

[0103] In one embodiment, the bearing plate 22 is used to bear the first motion assembly 15, the second motion assembly 16, the first frame 17, the second frame 18, the first display instrument 13 and the second display instrument 14. The anti-vibration base 19 is disposed at the bottom of the bearing plate 22, and the anti-vibration base 19 can be used to suppress vibration.

[0104] See also Figure 7 In one embodiment, the test unit 1 may further include a fixture 20 , a second sensor 21 , a sensing unit 23 and a calibration block 24 .

[0105] Specifically, the fixture 20 is a loading platform for loading and fixing the object to be tested 106. The second sensor 21 can be used as an initialization feedback device, and the second sensor 21 can be used to sense the displacement of the fixture 20, that is, the second sensor 21 can be used to calibrate the initial position of the fixture. The first machined part 25 is fixedly connected between the fixture 20 and the second motion component 16, and the second motion component 16 can control the rotation angle of the fixture 20.

[0106] In one embodiment, the first sensor 12 is fixed between the first frame 17 and the second machined component 26, and the second machined component 26 is fixed between the first sensor 12 and the sensing unit 23. It can be understood that the second machined component 26 can be fixed to the sensing unit 23 by bolts 27.

[0107] The sensing unit 23 may include at least two sensing elements 231. Figure 7 As shown, in this embodiment, only two sensing members 231 are shown as an example for illustration, but in other embodiments, the number of the sensing members 231 is not limited to 2 and can be adjusted according to actual needs. In the embodiment of the present application, the two sensing members 231 can be fixedly connected together by bolts.

[0108] It can be understood that, in one embodiment, the at least two sensing members 231 can be arranged in parallel. In other embodiments, they can also be arranged in an asymmetrical manner. This application does not make any specific limitation on this.

[0109] In one embodiment, each sensing element 231 has a groove 232 ( Figure 8c As shown in FIG. 2 , it can be understood that the sensing member 231 in the embodiment of the present application is an actuator that can be used to deform the SMA microwire and reflect the relaxation of the microwire. When the SMA microwire contacts the two sensing members 231 , the SMA microwire will be stuck in the groove 232 .

[0110] In one embodiment, the sensing element 231 may be in a hook shape. It is understood that the hook shape is not limited to a triangle, and in other embodiments, it may also be other shapes such as a semicircular arc, a semi-elliptical arc, a trapezoid, etc.

[0111] The fixture 20 is provided with at least two protrusions 201. In one embodiment, if the slack of the SMA microwire needs to be tested, the two terminals 202 of the SMA microwire can be fixed to the two protrusions 201 respectively, that is, the two terminals 202 of the object to be tested 106 can be fixed to the two protrusions 201 respectively.

[0112] In the embodiment of the present application, the calibration block 24 is a standard reference module for initialization position determination. Specifically, the calibration block 24 can be used to calibrate the first relative position of the first frame 17 and the first motion component 15, or to calibrate the first relative position of the first frame 17 and the second motion component 16. The calibration block 24 can be used as a reference, that is, the first relative position and the second relative position can be calibrated by the first sensor 12 and the second sensor 21.

[0113] See also Figure 8a-8c , Figure 8a-8c It is a state diagram of placing the object to be tested 106 on the testing unit 1 for testing.

[0114] like Figure 8a-8c As shown in FIG. 1 , the object to be tested 106 is an SMA microwire. The SMA microwire is fixed on a fixture. The SMA microwire is fixed at both ends of a receiving terminal and suspended between two terminals 202 . The SMA microwire is clamped between two sensing elements 231 .

[0115] In one embodiment, the terminal device 102 can send a control instruction to the motor controller, and the motor controller can control the movement of the second motion component 16 according to the control instruction. The movement of the second motion component 16 can be translational or rotational, and the rotation direction is not necessarily around the z-axis, but can be other directions. For example, the motor controller can control the second motion component 16 to rotate according to the control instruction, at which time, the SMA microwire will be driven to rotate relative to the sensing unit 23, and the SMA microwire will be deformed.

[0116] Thus, the first sensor 12 can measure the force applied to the SMA filament when it is deformed, and can feed back the data value of the sensed force to the control device 104 and the terminal device 102 .

[0117] See also Fig. 9 , Fig. 9is a graph showing the relationship between the rotation angle and the torque of the object to be measured 106. Fig. 9 It can be seen that when the rotation angle of the object under test 106 is less than the preset angle, since the object under test 106 is in a zero drift or fluctuation state at this time, the torque exerted on the object under test fluctuates around 0, and its fluctuation range is affected by the accuracy of the first sensor 12, the second machined part 26 and the sensing unit 23.

[0118] However, when the rotation angle of the object under test 106 is greater than or equal to a specific angle, the object under test 106 begins to generate a torque, and the change of tension or stress caused by a small deformation is linear.

[0119] See also Fig.10 During the actual testing process, the testing device 100 of the embodiment of the present application needs to execute relevant steps to achieve accurate testing of the relaxation of the object to be tested 106. Fig.10 The test steps are shown as observed from the direction perpendicular to the XY plane, specifically:

[0120] Step 1: Before testing the slack of the object 106 to be tested, fix both ends of the object 106 to be tested on the fixture 20 .

[0121] Next, the centers of the two sensing elements 231 in the XY plane are aligned with the centers of the two terminals 202 of the object to be measured 106 , and the plane where the terminals 202 are located corresponds to the grooves 232 of the sensing elements 231 .

[0122] Therefore, when the second motion component 16 starts to rotate around the Z axis, the object to be tested 106 can be clamped in the groove 232 of the sensor 231, thereby preventing the object to be tested 106 from moving, thereby improving the accuracy of the microwire relaxation test.

[0123] Step 2: The motor controller controls the second motion component 16 to rotate clockwise, thereby driving the object to be measured 106 to rotate clockwise.

[0124] It is understood that the motor controller controls the rotation speed of the second motion component 16 to be lower than a first preset value until a torque change region appears, that is, when the object to be measured 106 rotates to a certain angle, the object to be measured 106 will contact the sensing element 231 and begin to deform to a certain extent. In one embodiment, the first preset value may be 0.1 rad / s, or even lower, such as 0.01 rad / s.

[0125] At this time, the sensing unit 23 can sense the force applied to the object to be tested when it is deformed, and transmit the sensed force to the first sensor 12. The first sensor 12 can obtain the value of the force applied to the object to be tested when it is deformed, so that the first curve of the change of torque with displacement, as well as the point where the torque change begins and the point where the measurement ends can be recorded, and the test data can be fed back to the control device 104 and the terminal device 102 to analyze the test data. It can be understood that the end point of the test cannot exceed the yield strength of the material. In one embodiment, it cannot exceed one-half of the yield strength. Among them, the yield strength refers to the yield limit of the metal material when the yield phenomenon occurs, that is, the stress that resists slight plastic deformation. For metal materials without obvious yield, the stress value that produces 0.2% residual deformation is specified as its yield limit, which is called conditional yield limit or yield strength.

[0126] Step 3: The motor controller controls the second motion component 16 to rotate counterclockwise, thereby driving the object to be measured 106 to rotate counterclockwise.

[0127] It can be understood that the motor controller controls the rotation speed of the second motion component 16 to be lower than a second preset value until a region of linear torque change appears, that is, when the object to be measured 106 rotates to a certain angle, the object to be measured 106 will contact the sensing member 231 and begin to produce a certain degree of deformation. At this time, the second curve of the torque changing with the displacement, as well as the point where the torque starts to change and the point where the measurement ends can be recorded, and the test data can be fed back to the control device 104 and the terminal device 102 to analyze the test data.

[0128] Step 4: The control device 104 and the terminal device 102 calculate the value of the relaxation ΔL at this time through the recorded test data and the corresponding algorithm.

[0129] It can be understood that in the above test steps, in order to ensure the feasibility of the calculation method, the following situations may exist:

[0130] 1. Under extremely short angle changes, the deformation of SMA microfilaments is also linear;

[0131] 2. The thickness of the sensing element 231 perpendicular to the direction of the SMA microwire can be ignored;

[0132] 3. The centers of the two sensing elements 231 and the centers of the two terminals 202 are aligned;

[0133] 4. The physical properties of the wire material are uniform;

[0134] 5. The temperature effect can be ignored;

[0135] 6. Satisfy Saint-Venant’s principle of small deformation in material mechanics.

[0136] During the experiment, the test method of the embodiment of the present application and the test methods of prior art 1 and prior art 2 were used respectively to obtain relevant data on test error, test efficiency and test stability, as shown in Table 1 below.

[0137] Table 1

[0138]

[0139]

[0140] It can be seen from Table 1 above that the test method according to the embodiment of the present application has smaller test error, higher test efficiency and better test stability.

[0141] Therefore, the slack of the SMA microwire can be tested online in real time. In addition, after the production is completed, the deviation statistics of the SMA microwire processing slack value can be obtained to better improve the SMA motor process design and control the quality of the product. The test method for testing the slack of the SMA microwire adopted in the embodiment of the present application has fast test speed, high accuracy and good stability.

[0142] See also Fig.11 , Fig.11 The present invention is a flow chart of a test method for testing the relaxation of SMA microfilaments according to an embodiment of the present application. The test method may include the following steps:

[0143] Step S111, system initialization.

[0144] In the embodiment of the present application, the control device and the system are initialized before the object to be tested is tested. Specifically, the test system can automatically initialize and reset to the corresponding position according to the initial position information and the calibration information of the detection position.

[0145] Step S112, placing the object to be tested on the fixture.

[0146] Specifically, the embodiment of the present application can fix the object to be tested on the fixture. In the embodiment of the present application, the two terminals of the object to be tested can be fixed on the two protrusions on the fixture respectively, that is, the fixture loads and fixes the object to be tested. It can be understood that in some embodiments, the object to be tested can be placed on the fixture by manual loading, and the object to be tested is installed and clamped on the fixture.

[0147] Step S113, detect whether the object to be tested is loaded successfully. If yes, proceed to step S114, otherwise return to step S112.

[0148] Specifically, after the system completes initialization, it is necessary to detect whether the object to be tested is successfully loaded. In the embodiment of the present application, a visual system can be used to visually detect whether the object to be tested is successfully loaded. If the object to be tested is successfully loaded, the next step of the test process begins.

[0149] Step S114, the test starts.

[0150] In the embodiment of the present application, when it is determined that the object to be tested is successfully loaded, the object to be tested can be tested. At this time, the double working button can be pressed, and the first motion component and the second motion component will move to the corresponding test point and prepare for the preset test action.

[0151] Step S115, the fixture moves along a preset trajectory.

[0152] In an embodiment of the present application, the object to be tested can be arranged between two sensing members. When the jig rotates, the object to be tested contacts the two sensing members and deforms. Furthermore, grooves can be provided on both sensing members. Therefore, when the object to be tested contacts the two sensing members, the object to be tested can be clamped in the grooves of the sensing members.

[0153] The terminal device sends a control instruction to the motor controller, and the motor controller controls the motion component to move according to the preset action according to the received control instruction. That is, the motion component drives the fixture to rotate under the drive of the motor controller.

[0154] For example, in one embodiment, the preset trajectory motion may be a clockwise rotation or a counterclockwise rotation. For example, the motor controller may control the motion component to rotate clockwise according to the control instruction, thereby driving the object to be tested to rotate clockwise. The motor controller may also control the motion component to rotate counterclockwise according to the control instruction, thereby driving the object to be tested to rotate counterclockwise.

[0155] Step S116: The first sensor collects test data and transmits it to the terminal device for calculation.

[0156] When the fixture moves along a preset trajectory, the object to be tested is driven to move. Thus, during the displacement of the object to be tested, when the object to be tested contacts the sensing unit, the object to be tested will begin to deform to a certain extent.

[0157] At this time, the sensing unit can sense the force applied to the object to be tested when it is deformed, and transmit the sensed force to the first sensor. The first sensor can obtain the value of the force applied to the object to be tested when it is deformed. Therefore, the relevant curve of the change of torque with displacement can be recorded according to the data sensed by the first sensor, and then the relevant test data can be obtained, and the test data can be fed back to the control device and the terminal device to analyze the test data.

[0158] Step S117, calculate the test data and display the calculation results.

[0159] In the embodiment of the present application, the terminal device can calculate the relaxation value of the object to be measured through a relevant algorithm. Therefore, the user can view the calculation result through the display of the terminal device.

[0160] Step S118, determining whether the slack value of the object to be tested is within a preset range. If so, proceed to step S119, otherwise return to step S114.

[0161] After obtaining the slack of the object to be tested, the obtained slack is compared with a preset range. That is, combined with error analysis, it can be concluded whether the test result is reasonable. If the test is not within the preset range for 3 times, the test is terminated.

[0162] When the slack value of the object to be measured is not within the preset range, data analysis is required. If the point data is incorrect, reinitialization is required.

[0163] Step S119, the motion component returns to the loading origin.

[0164] In the embodiment of the present application, when it is determined that the slack value of the object to be tested is within a preset range, the test is marked as successful, and thus the test is ended, and the slack test of the next object to be tested can be performed.

[0165] The test device and method for testing the slack of SMA microfilaments provided in the embodiments of the present application can accurately measure the slack of SMA microfilaments, solving the problem of insufficient testing accuracy of existing solutions. The test device and method in the embodiments of the present application have high measurement accuracy, making it easy to measure extremely small slack.

[0166] In the embodiment of the present application, since the small deformation test method utilizes the mechanical properties of small deformation of the material, in the small deformation range, the stress can change linearly, and such properties can support the completion of high-precision testing. Since the metal wire only produces a small linear deformation. Therefore, the test method of the present application will not damage the product, and the product can continue to be processed.

[0167] By adopting the embodiments of the present application, the test accuracy can be effectively improved, and the test efficiency can be improved. The test device is small in size and easy to use.

[0168] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or basic features of the present application. Therefore, as long as they are within the scope of the essence and spirit of the present application, appropriate changes and modifications made to the above embodiments should fall within the scope of protection claimed in the present application.

Claims

1. A testing device for testing the relaxation of shape memory alloy microwires, characterized in that: The testing device includes a fixture, a motion component, a sensing unit, a first sensor and a second sensor; The fixture is used to fix and clamp the shape memory alloy microwire, wherein the shape memory alloy microwire is fixed at both ends of the receiving terminal and suspended between the two terminals; The motion component is fixedly connected to the fixture and is used to drive the fixture to move under the drive of the motor controller; The sensing unit includes at least two sensing members, and the shape memory alloy microwire is disposed between the at least two sensing members; when the jig moves, the shape memory alloy microwire contacts the sensing member and deforms; The second sensor is used to sense the displacement of the fixture and transmit the measured data to the terminal device. The first sensor is fixedly connected to the sensing unit and is used to measure the force applied to the shape memory alloy microwire during deformation and transmit the measured data to the terminal device to calculate the relaxation of the shape memory alloy microwire; the relaxation is the difference between the actual length of the shape memory alloy microwire and the distance between the two terminals.

2. The testing device according to claim 1, characterized in that: The jig comprises a first protrusion and a second protrusion, and two ends of the shape memory alloy microwire are fixedly connected to the first protrusion and the second protrusion respectively.

3. The testing device according to claim 1 or 2, characterized in that: The center point between the two sensing elements is butted against the center point of the shape memory alloy microwire.

4. The testing device according to claim 1, characterized in that: The sensing element is provided with a groove, and when the shape memory alloy micro-wire contacts the sensing element, the shape memory alloy micro-wire is held in the groove.

5. The testing device according to claim 1, characterized in that: The testing device further includes a first display instrument, the first sensor is connected to the first display instrument via a cable, and the first display instrument is used to display the value of the force measured by the first sensor.

6. The testing device according to claim 5, characterized in that: The testing device further includes a first frame, and the first frame is used to fix the first sensor.

7. The testing device according to claim 6, characterized in that: The testing device further comprises a calibration block, and the calibration block is used to calibrate the relative position of the first frame and the motion component.

8. The testing device according to claim 6, characterized in that: The testing device further comprises a bearing plate and a seismic-resistant base, wherein the bearing plate is used for bearing the first frame, the moving assembly and the first display instrument, and the seismic-resistant base is used for suppressing vibration.

9. A test method for testing the relaxation of shape memory alloy microwires, characterized in that: The testing method comprises the following steps: Fixing and clamping the shape memory alloy microwire on the fixture, wherein the shape memory alloy microwire is fixed to two ends of the receiving terminal and suspended between the two ends; The jig is driven to move under the drive of the motor controller; The shape memory alloy microwire is arranged between at least two sensing elements; when the jig moves, the shape memory alloy microwire contacts the sensing elements and deforms; sensing the displacement of the fixture and transmitting the measured data to a terminal device; The force applied to the shape memory alloy microwire during deformation is measured, and the measured data is transmitted to a terminal device to calculate the relaxation of the shape memory alloy microwire; the relaxation is the difference between the actual length of the shape memory alloy microwire and the distance between the two terminals.

10. The testing method according to claim 9, characterized in that: The fixing and clamping of the shape memory alloy microwire on the fixture further comprises: The two ends of the shape memory alloy microwire are respectively fixedly connected to the first protrusion and the second protrusion on the fixture.

11. The testing method according to claim 9 or 10, characterized in that: The test method also includes: The center point between the two sensing elements is butted against the center point of the shape memory alloy microwire.

12. The testing method according to claim 9, characterized in that: The test method also includes: When the shape memory alloy micro-wire contacts the sensing element, the shape memory alloy micro-wire is clamped in the groove of the sensing element.

13. The testing method according to claim 9, characterized in that: The step of driving the fixture to move under the drive of the motor controller further comprises: The motion component drives the fixture to rotate; Wherein, the rotation speed of the fixture is lower than a preset value.

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