Variable stiffness SMA wire sleeve type wide temperature range heat regulation and control device and method

Abstract

The invention discloses a variable-stiffness SMA wire sleeve type wide-temperature-range heat regulation and control device and method, and aims to provide a stable, wide-temperature-range and quick-response temperature environment for an SMA wire so as to realize quick change and stable maintenance of the stiffness of the SMA wire. The device comprises a cold air nozzle, a refrigerating device, a temperature controller, a heat insulation material, a heating device, a copper sleeve, a memory alloy wire, an insulating sleeve and a temperature measuring device. According to the device, low-temperature gas is generated through sublimation of dry ice, the opening and closing duration of a cold air nozzle and the duty ratio of a heating wire are accurately controlled through a provided temperature control method, wide-temperature-range rapid adjustment and stable maintenance of the temperature in the sleeve are achieved, and the rigidity of the SMA wire is accurately controlled. The insulating sleeve effectively prevents the SMA wire from being in contact with the copper sleeve, ensures the accuracy of resistance measurement, realizes variable stiffness, and self-senses the mechanical state of the SMA wire at the same time. Technical support can be provided for the variable-stiffness intelligent structure, and powerful guarantee is provided for research and application of intelligent materials.

Description

Technical Field

[0001] The invention patent belongs to the field of intelligent material performance control, and particularly relates to a variable stiffness SMA wire sleeve type wide temperature range thermal control device and method. Background Art

[0002] As a new type of intelligent material, shape memory alloy wire has been widely used in many fields due to its shape memory effect and superelasticity. Especially in high-tech industries such as aerospace, medical, and automobiles, shape memory alloy wire has shown great application potential due to its light weight, high strength, and variable stiffness.

[0003] In the aerospace field, shape memory alloy wire, as a smart antenna material, can maintain stable working performance in the extremely low temperature environment of space. Its excellent temperature adaptability and shape recovery characteristics make it an ideal choice for smart material systems in space, and it can adaptively adjust its shape by changing the temperature to meet the requirements of spacecraft.

[0004] In the aviation field, shape memory alloy wires are used in small drive devices. Through precise temperature control, they can control the precise movement of the mechanism in a smaller space, which plays an important role in lightweighting. This is of great significance for optimizing aircraft structure and improving fuel efficiency.

[0005] In the medical field, shape memory alloy wire, as the core material of medical devices such as heart stents, can exert its shape recovery function in an environment with changing body temperature, help support and repair blood vessels, and has excellent biocompatibility and high strength.

[0006] In the automotive field, shape memory alloy wires are used in key components such as the vehicle's shock absorption system and oil circuit control. Through temperature-driven variable stiffness characteristics, they can achieve adaptive adjustment at different operating temperatures, thereby improving the comfort and handling of the vehicle.

[0007] However, the performance of shape memory alloy wire is greatly affected by temperature changes, and the performance differences between different alloy compositions and material types are significant. In order to ensure the functionality of shape memory alloy wire in practical applications, it is necessary to accurately control the temperature of the memory alloy wire. The present invention proposes a variable stiffness SMA wire sleeve type wide temperature range thermal regulation device and method. The device uses dry ice sublimation to generate low-temperature gas, and uses an energized heating wire to create a high-temperature environment. Through the proposed temperature control method, the opening and closing time of the cold air nozzle and the duty cycle of the energized heating wire are reasonably and efficiently controlled to achieve rapid wide temperature range adjustment and stable maintenance of the temperature in the sleeve, so that the stiffness of the shape memory wire in the sleeve can respond accurately and quickly, providing strong technical support for the future research and development of intelligent structures. Summary of the invention

[0008] The purpose of the present invention is to provide a variable-stiffness SMA wire sleeve type wide temperature range thermal control device and method. The device quickly and accurately controls the temperature of the shape memory alloy wire in the sleeve by adjusting the power-on time of the heating wire and the opening and closing time of the cold air nozzle, thereby achieving the requirement of accurate and rapid change of the stiffness of the memory alloy wire.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] A variable-rigidity SMA wire sleeve type wide-temperature range thermal control device comprises a cold air nozzle 1, a refrigeration device 2, a temperature controller 3, a thermal insulation material 4, a heating device 5, a copper sleeve 6, a memory alloy wire 7, an insulating sleeve 8 and a temperature measuring device 9.

[0011] The cold air nozzle 1 is connected to the copper sleeve 6 by welding, and the connection position is in the middle of the copper sleeve. The copper sleeve 6 is punched at the corresponding position of the welding; the heating device 5 is an energized heating wire, which is evenly spirally wound on the outer surface of the copper sleeve 6; the thermal insulation material 4 adopts thermal insulation foam to cover the outer surface of the copper sleeve 6, and silver brushed adhesive is wrapped outside the thermal insulation foam to further reduce heat radiation; holes are punched at equal intervals on the surface of the copper sleeve 6, and the temperature measuring device 9 adopts a platinum resistor and is pasted on the inner surface of the copper sleeve 6; the insulating sleeve 8 adopts polyimide material, is connected to the copper sleeve 6 by interference fit, and has an opening at the corresponding position of the cold air nozzle; the memory alloy wire 7 is placed in the middle position of the polyimide sleeve and does not contact the copper sleeve.

[0012] The refrigeration device 2 is composed of a stainless steel cylinder 202, a heat preservation barrel 201, a sealing part 203 and an electromagnetic control valve 204. The space between the stainless steel cylinder 202 and the heat preservation barrel 201 is filled with a foaming heat preservation material. A threaded hole is provided on the top of the stainless steel cylinder body, which is threadedly matched with the sealing part 203. When in use, dry ice is placed inside the stainless steel cylinder 202, and the high-pressure carbon dioxide gas generated by the sublimation of the dry ice is input to the surface of the memory alloy wire 7, so as to achieve rapid cooling inside the memory alloy wire 7 and the copper sleeve 6. The sealing part 203 has a pressure relief valve to ensure the safety of the cylinder body and a control valve to control the exhaust of the gas cylinder. The control valve and the electromagnetic control valve 204 are connected with a low-temperature resistant hose. The input end of the temperature controller 3 is connected to the temperature measuring device 9, and the output end is connected to the heating device 5 and the electromagnetic control valve 204 to control the temperature inside the copper sleeve to be constant.

[0013] A control method for a variable-rigidity SMA wire sleeve type wide-temperature range heat control device: first, dry ice is placed in a stainless steel bottle 202, and sealed with a sealing part 203, and all valves of the sealing part are closed. After the dry ice bucket is completely cooled, the target temperature of the copper sleeve is set in the temperature controller, and the electrical signal of the multi-channel temperature measuring device is collected in real time, and the average is taken as the current temperature inside the copper sleeve. At the same time, the temperature signal collected for the first time is taken as the current ambient temperature. The temperature controller dynamically selects a temperature control scheme and a temperature maintenance scheme according to the temperature difference between the current temperature and the target temperature to achieve accurate temperature control. When the difference between the current temperature and the target temperature is less than a given threshold, the temperature controller switches to the temperature maintenance scheme to keep the current temperature stable. When the temperature difference is large, the temperature control scheme is entered. In the temperature increase control scheme, the controller divides the power of the heating device into multiple gears according to the temperature difference in advance, and adjusts the heating power in real time according to the current temperature to achieve a rapid and stable temperature increase. In the temperature reduction control scheme, the controller divides the opening and closing time of the cold air per unit time into several gears according to the temperature difference to achieve a rapid and stable temperature drop. When the current temperature difference is less than a given threshold, the temperature controller uses a temperature maintenance scheme to control the casing temperature. The temperature maintenance scheme has three control strategies: high temperature maintenance, low temperature maintenance and normal temperature maintenance. When the target temperature is lower than the ambient temperature, a low temperature maintenance strategy is adopted. In this mode, the cold air nozzle is divided into multiple gears according to the target temperature. Each gear is set with a different ventilation time. At the same time, PID control is used to adjust the duty cycle of the heating device to ensure that the temperature is stable at the target value. If the target temperature is higher than the ambient temperature, a high temperature maintenance strategy is adopted. At this time, the cold air nozzle is closed, and PID controls the power of the heating device to achieve high temperature maintenance. When the target temperature is close to the ambient temperature, a normal temperature maintenance strategy is adopted. The opening and closing of the cold air nozzle and the on and off of the heating device are adjusted simultaneously through PID control to achieve stable temperature maintenance. Through the above control method, the temperature in the copper casing can be quickly adjusted and stably maintained, thereby accurately controlling the stiffness change of the shape memory alloy wire.

[0014] The advantages of the present invention are:

[0015] 1. Through the method of sleeve thermal regulation, a stable and controllable temperature environment is provided for the shape memory alloy wire to meet the demand for variable stiffness of the shape memory alloy wire, and a solution is provided for the research on variable stiffness intelligent structure of the shape memory alloy wire.

[0016] 2. Generate cold air through dry ice sublimation, quickly create a low-temperature environment, with less energy consumption and fast response speed.

[0017] 3. Through the proposed multi-mode and multi-speed temperature regulation method, the temperature in the casing can be rapidly regulated and stably maintained over a wide temperature range, ensuring the rapid response of the stiffness change of the shape memory alloy wire and the long-term stability of the stiffness maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the overall structure: 1. Cold air nozzle 2. Refrigeration device 3. Temperature controller 4. Thermal insulation material 5. Heating device 6. Copper casing 7. Memory alloy wire 8. Insulation casing 9. Temperature measuring device

[0019] Figure 2 Refrigeration device schematic diagram Wherein: 201. Insulated barrel 202. Stainless steel cylinder 203. Sealing parts 204. Solenoid control valve (204)

[0020] Figure 3 Control method diagram DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings:

[0022] like Figure 1 A variable stiffness superelastic shape memory alloy wire sleeve type wide temperature range thermal control device is shown, the main structure of which is composed of a cold air nozzle (1), a refrigeration device (2), a temperature controller (3), a heat insulation material (4), a heating device (5), a copper sleeve (6), a memory alloy wire (7), an insulating sleeve (8) and a temperature measuring device (9).

[0023] The cold air nozzle (1) is connected to the copper sleeve (6) by welding, and the connection position is located in the middle of the copper sleeve, and a hole is punched at the welding point. The heating device (5) is an energized heating wire, which is evenly spirally wound on the outer surface of the copper sleeve (6); the heat insulation material (4) is a heat insulation foam, which is covered on the outer surface of the copper sleeve (6), and a silver brushed adhesive is wound on the outer layer to further reduce heat radiation. The surface of the copper sleeve (6) is evenly spaced, and the temperature measuring device (9) is a platinum resistor, which is attached to the inner surface of the copper sleeve (6). The insulating sleeve (8) is a polyimide sleeve, which is connected to the copper sleeve (6) by an interference fit, and an opening is provided at the cold air nozzle. The memory alloy wire (7) is placed in the middle of the polyimide sleeve and does not contact the surface of the copper sleeve (6).

[0024] like Figure 2As shown, the refrigeration device 2 is composed of a stainless steel cylinder (202), an insulation barrel (201), a sealing part (203) and an electromagnetic control valve (204). Foaming insulation material is filled between the stainless steel cylinder (202) and the insulation barrel (201). A threaded hole is provided on the top of the stainless steel bottle body, and is threadedly matched with the sealing part (203). When in use, dry ice is placed inside the stainless steel cylinder (202). The high-pressure carbon dioxide gas generated by the sublimation of the dry ice passes through the middle of the copper sleeve (6) through the cold air nozzle (1), flows from the middle of the memory alloy wire to both sides, and finally blows out from both ends of the copper sleeve (6), thereby realizing rapid cooling of the memory alloy wire. The sealing part (203) is provided with a pressure relief valve and a control valve for controlling the exhaust of the gas cylinder. The control valve and the electromagnetic control valve (204) are connected by a low-temperature resistant hose. The input end of the temperature controller (3) is connected to the temperature measuring device (9), and the output end is connected to the heating device (5) and the electric control gas valve (204), and is used to control the temperature stability in the copper sleeve.

[0025] like Figure 3 As shown, after the dry ice bucket is completely cooled, first, the target temperature of the copper sleeve (6) is set by using the temperature controller (3), and the temperature electrical signal is collected in real time by the multi-channel temperature measuring device (9), and the average value is taken as the current temperature inside the copper sleeve (6). At the same time, the temperature signal collected for the first time is used as the current ambient temperature and is saved by the temperature controller (3). The temperature controller (3) has an ambient temperature input interface, which allows the ambient temperature to be adjusted at any time as needed to ensure the flexibility of the temperature control process.

[0026] The temperature controller (3) has two control schemes: temperature regulation and temperature maintenance. An adjustable threshold is set in the controller. When the difference between the current temperature of the copper sleeve (6) and the target temperature is less than a given threshold, the temperature controller (3) automatically switches to the temperature maintenance scheme. When the difference between the current temperature and the target temperature is greater than the threshold, the temperature controller (3) activates the temperature regulation scheme.

[0027] The temperature adjustment scheme includes two adjustment methods: heating and cooling. The controller divides the adjustment power into several gears according to the temperature difference between the current temperature and the target temperature, thereby realizing rapid temperature adjustment. The temperature range and power of each gear have an adjustment interface, which can be customized by the user to meet different temperature adjustment requirements. During specific operation, the temperature controller collects the temperature signal of the temperature measuring device in real time, calculates the difference between the current temperature and the target temperature, and matches the corresponding temperature adjustment gear according to the difference, thereby realizing rapid and accurate temperature adjustment. The heating power is adjusted by the duty cycle of the heating device (5), and the cooling power is realized by the length of time that the preset cold air nozzle releases cold air per unit time.

[0028] When the temperature sensor detects that the difference between the current temperature and the target temperature is less than a given threshold, the controller automatically switches from the temperature adjustment scheme to the temperature maintenance scheme. The temperature maintenance scheme has three control strategies: high temperature maintenance, low temperature maintenance, and normal temperature maintenance. If the target temperature is lower than the ambient temperature, the low temperature maintenance strategy is adopted. If the target temperature is higher than the ambient temperature, the high temperature maintenance strategy is adopted. If the target temperature is close to the ambient temperature, the normal temperature maintenance strategy is adopted.

[0029] In low temperature maintenance mode, the temperature controller divides the cold air nozzle into several gears according to the set target temperature, and sets different ventilation time for each gear to adjust the amount of cold air released. At the same time, the controller adjusts the duty cycle of the heating device through PID control to ensure that the temperature is stable at the set target temperature. In normal temperature maintenance mode, PID control simultaneously adjusts the opening and closing of the cold air nozzle and the on and off of the heating wire to achieve stable temperature maintenance. In high temperature maintenance mode, the cold air nozzle remains closed, and the PID controller accurately adjusts the power of the heating device to achieve high temperature maintenance.

[0030] At the same time, the insulating sleeve (8) can effectively prevent the memory alloy wire from contacting the copper sleeve, so that the resistance of the memory alloy wire can be accurately measured, and the mechanical state of the memory alloy wire can be self-sensed by measuring the resistance while changing the stiffness.

Claims

1. A variable stiffness SMA wire sleeve type wide temperature range heat control device, the main structure of which is composed of a cold air nozzle (1), a refrigeration device (2), a temperature controller (3), a heat insulation material (4), a heating device (5), a copper sleeve (6), a memory alloy wire (7), an insulating sleeve (8) and a temperature measuring device (9), wherein the cold air nozzle (1) is connected to the copper sleeve (6) by welding, and the connection position is in the middle of the copper sleeve, and the copper sleeve (6) is punched at the corresponding position of the welding; the heating device (5) is an energized heating wire, which is evenly spirally wound on the copper sleeve (6). the outer surface of the copper sleeve (6); the heat-insulating material (4) is a heat-insulating foam sleeve on the outer surface of the copper sleeve (6), and a silver brushed adhesive is wrapped around the heat-insulating foam to further reduce heat radiation; holes are punched at equal intervals on the surface of the copper sleeve (6); the temperature measuring device (9) is a platinum resistor and is pasted on the inner surface of the copper sleeve (6); the insulating sleeve (8) is a polyimide sleeve, which is connected to the copper sleeve (6) by an interference fit, and a hole is opened at a position corresponding to the cold air nozzle; the memory alloy wire (7) is placed in the middle of the polyimide sleeve and does not contact the copper sleeve (6).

2. The variable stiffness SMA wire sleeve type wide temperature range thermal control device according to claim 1, characterized in that: The refrigeration device (2) is composed of a stainless steel cylinder (202), a heat preservation barrel (201), a sealing part (203) and an electromagnetic control valve (204). The space between the stainless steel cylinder (202) and the heat preservation barrel (201) is filled with a foaming heat preservation material. A threaded hole is provided on the top of the stainless steel cylinder body, which is threadedly matched with the sealing part (203). When in use, dry ice is placed inside the stainless steel cylinder (202), and high-pressure carbon dioxide gas generated by sublimation of the dry ice is blown onto the surface of the memory alloy wire (7) through the cold air nozzle (1). The sealing part (203) has a pressure relief valve for ensuring the safety of the cylinder body and a control valve for controlling the exhaust of the gas cylinder. The control valve and the electromagnetic control valve (204) are connected by a low-temperature resistant hose. The input end of the temperature controller (3) is connected to a temperature measuring device (9), and the output end is connected to a heating device (5) and the electromagnetic control valve (204), so as to control the temperature inside the copper sleeve (6) to be constant.

3. A control method for a variable stiffness SMA wire sleeve type wide temperature range thermal control device, characterized in that: The target temperature of the copper sleeve (6) is set by using a temperature controller (3), and the electrical signals of the multi-channel temperature measuring device (9) are collected in real time, and the average value is taken as the current temperature inside the copper sleeve (6), and the temperature signal collected for the first time is used as the current ambient temperature. At the same time, the temperature controller (3) retains an ambient temperature input interface, which can be adjusted at any time; the temperature controller (3) is set with two control schemes: temperature adjustment and temperature maintenance. An adjustable threshold is provided in the controller. When the difference between the current temperature of the copper sleeve (6) and the target temperature is less than a given threshold, the temperature controller (3) adopts a temperature maintenance scheme, and when the difference between the current temperature of the copper sleeve (6) and the target temperature is greater than the given threshold, the temperature controller (3) adopts a temperature maintenance scheme. When the temperature reaches a certain value, a temperature adjustment scheme is adopted; the temperature adjustment scheme includes two adjustment methods: heating and cooling. When the temperature adjustment method is adopted, the controller divides the adjustment power into several gears according to the temperature difference between the current temperature and the target temperature to achieve rapid temperature adjustment. The gear setting has an adjustable interface, and the temperature range and power of each gear can be adjusted to meet different temperature adjustment requirements. When in use, the temperature controller collects the temperature signal of the temperature measuring device in real time, calculates the difference between the current temperature and the target temperature, and matches the corresponding temperature adjustment gear to achieve rapid and accurate temperature adjustment. The heating power is transmitted through the heating device (5) The duty cycle is realized, and the cooling power is realized by presetting the length of time for the cold air nozzles in each gear to release cold air per unit time; when the temperature controller detects that the difference between the current temperature and the target temperature is less than a given threshold, the temperature sensor changes from the temperature adjustment scheme to the temperature maintenance scheme. The temperature maintenance scheme has three control strategies: high temperature maintenance, low temperature maintenance and normal temperature maintenance. When the target temperature is lower than the ambient temperature, the low temperature maintenance control strategy is adopted. When the target temperature is higher than the ambient temperature, the high temperature maintenance strategy is adopted. When the target temperature is close to the ambient temperature, the normal temperature maintenance control strategy is adopted. In the low temperature maintenance mode, the temperature controller According to the set target temperature, the cold air nozzle is divided into several gears, and a different ventilation time is set for each gear. At the same time, the duty cycle of the heating device is adjusted through PID control to ensure that the temperature is stable at the target temperature; the normal temperature maintenance strategy uses PID to simultaneously control the opening and closing of the cold air nozzle and the on and off of the heating wire to achieve stable temperature maintenance; when the high temperature maintenance strategy is adopted, the cold air nozzle remains closed, and the power of the heating device is controlled by PID to achieve high temperature maintenance. Through the above method, the temperature in the sleeve can be quickly regulated and accurately maintained, so as to achieve rapid and accurate change and maintenance of the stiffness of the memory alloy wire.

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