Cutting force and cutting temperature measuring method and device for solid propellant shaping

Abstract

The invention discloses a cutting force and cutting temperature measuring method and device for solid propellant shaping, and belongs to the field of solid rocket engine propellant shaping machining. The cutting force and cutting temperature measuring device comprises a force and temperature measuring tool, comprises an acoustic surface wave temperature measuring module and an acoustic surface wave force measuring module which are mounted on a tool bit of the shaping tool, and is used for monitoring the cutting temperature and cutting force of the tool in real time; and the radio frequency reader system is in signal connection with the force-measuring and temperature-measuring cutter and is used for receiving, transmitting and processing the signal transmitted by the force-measuring and temperature-measuring cutter. The surface acoustic wave sensing technology is adopted, wireless and passive measurement of the cutting force and the cutting temperature of shaping machining of the solid propellant is achieved, and good anti-explosion performance and use flexibility are achieved; according to the radio frequency reader, the software radio technology is adopted, the equipment development period is short, the cost is low, and system maintenance and upgrading are facilitated; according to the method, coherent averaging can be carried out on echo signals, the signal-to-noise ratio of the signals is improved, and higher frequency estimation resolution and stability are achieved.

Description

Technical Field

[0001] The invention belongs to the field of solid rocket engine propellant shaping processing, and in particular relates to a cutting force and cutting temperature measurement method and device for solid propellant shaping. Background Art

[0002] In the aerospace field, solid rocket engines, as power devices for various launch vehicles and missile weapons, provide strong power support for their safe flight and are often referred to as the heart of launch vehicles and missiles. The solid propellant shaping process is an important part of its preparation process. At present, the propellant shaping work in my country is generally done manually, but solid propellants are flammable and explosive dangerous goods. The friction and cutting forces generated during the shaping process continuously accumulate heat. Once the ignition point is reached, it is very easy to cause safety accidents. Therefore, it is very necessary to monitor the cutting temperature and cutting force of the tool in the shaping process in real time.

[0003] In recent years, in order to achieve real-time monitoring of tool cutting temperature and cutting force during shaping, there have been many technological innovations. For example, Chinese patent application CN201420795203.X introduces a solid propellant shaping tool assembly, which uses platinum resistance to achieve accurate temperature measurement and real-time monitoring of the tool head temperature; Chinese patent application CN201810705611.4 introduces a solid fuel ultrasonic assisted shaping tool, which uses ultrasonic vibration to change the traditional cutting mode and reduce the temperature during processing; Chinese patent application CN202311831392.1 introduces a human-machine collaborative remote control system and method for solid propellant shaping and deviation compensation, which uses a micro infrared temperature sensor head to monitor the temperature of the shaping cutting area. The above temperature measurement methods all use traditional temperature sensors. Platinum resistance temperature sensors are wired active sensors that require connecting wires. The existence of connecting wires limits the flexibility of shaping, and active sensors will produce spark discharges due to static electricity, short circuits, etc., which poses a great safety hazard; infrared temperature sensors are easily blocked by chips, affecting the temperature measurement effect.

[0004] The surface acoustic wave temperature sensor is made by utilizing the property that the propagation velocity of surface acoustic waves changes with the physical and chemical properties of the piezoelectric substrate. The surface acoustic wave temperature sensor has the characteristics of wireless passivity, high sensitivity and excellent explosion-proof performance, and is very suitable for solid propellant cutting temperature measurement. In recent years, surface acoustic wave sensors have had many applications in the field of mechanical processing. For example, Chinese patent application CN201310078061.5 introduces an intelligent tool based on a surface acoustic wave sensing system, which is applied to turning tool blades to realize the measurement of cutting force and cutting temperature; Chinese patent application 202410799129.7 introduces a tool with a surface acoustic wave sensor, a tool stress monitoring method and a system; the above method does not take into account the characteristics of cutting force and cutting temperature changes, and simultaneous measurement of cutting force and cutting temperature is prone to signal crosstalk.

[0005] The surface acoustic wave temperature sensor requires a radio frequency reader for identification. However, the hardware circuit of the traditional radio frequency reader is complex and difficult to upgrade and maintain. Therefore, a software radio platform is used to develop a surface acoustic wave radio frequency reader. Summary of the invention

[0006] The purpose of the present invention is to provide a cutting force and cutting temperature measurement method and device for solid propellant shaping, so as to realize wireless passive real-time monitoring of cutting temperature and cutting force of solid propellant shaping processing, and solve the problems of insufficient processing flexibility and potential safety hazards of existing force and temperature measuring tools.

[0007] The technical solution adopted by the present invention is:

[0008] A cutting force and cutting temperature measuring device for solid propellant shaping, comprising:

[0009] The force and temperature measuring tool comprises a surface acoustic wave temperature measuring module and a surface acoustic wave force measuring module installed on the shaping tool head, and is used for real-time monitoring of the tool cutting temperature and cutting force;

[0010] The radio frequency reader system is connected with the force and temperature measuring tool signal to transmit, receive and process the signal transmitted by the force and temperature measuring tool.

[0011] A method for measuring cutting force and cutting temperature of a solid propellant shaping device, wherein the radio frequency reading steps of the surface acoustic wave temperature sensor are as follows:

[0012] Step 1: The host computer generates a digital baseband signal;

[0013] Step 2: The software radio platform converts the digital baseband signal into analog digital form;

[0014] Step 3: The software radio platform generates a carrier signal and mixes it with the baseband signal to obtain an excitation signal;

[0015] Step 4: The software radio platform transmits an excitation signal through the copper rod antenna;

[0016] Step 5: The surface acoustic wave temperature sensor or the surface acoustic wave strain gauge of the shaping tool head is excited to send out an echo signal;

[0017] Step 6: The software radio platform receives the echo signal through the copper rod antenna;

[0018] Step 7: The software radio platform down-converts the echo signal to obtain an echo baseband signal;

[0019] Step 8: The software radio platform converts the analog baseband signal into digital form and uploads it to the host computer for storage;

[0020] Step 9: Repeat steps 1 to 8 until 50 echo signals are collected;

[0021] Step 10: The host computer performs coherent averaging and frequency estimation on the 50 echo signals;

[0022] Step 11: Repeat steps 1 to 10 until all SAW temperature sensors or SAW strain gauges are read;

[0023] Step 12: Analyze and demodulate the data on the host computer to achieve force and temperature measurement.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention adopts surface acoustic wave sensing technology to realize wireless passive measurement of cutting force and cutting temperature in solid propellant shaping processing, and has good explosion-proof performance and ease of use;

[0026] 2. The radio frequency reader of the present invention adopts software radio technology, which has a short equipment development cycle, low cost, and is easy to maintain and upgrade the system;

[0027] 3. The present invention can perform coherent averaging on echo signals, thereby improving the signal-to-noise ratio and having higher frequency estimation resolution and stability.

[0028] 4. The software radio platform of the present invention continuously transmits excitation signals and receives sensor echo signals, and a single-pole double-throw radio frequency switch controls the timing of transmission and reception, thereby realizing time-sharing transmission and reception using one antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is an exploded diagram of the force and temperature measuring tool of the present invention;

[0030] Figure 2 is a schematic diagram of a radio frequency reader system of the present invention;

[0031] Figure 3is a diagram of a surface acoustic wave sensor array of the present invention;

[0032] Figure 4 yes Figure 3 AA section view;

[0033] Figure 5 The temperature measurement impedance matching and power distribution circuit of the present invention;

[0034] Figure 6 is a schematic diagram of a force sensing unit of the present invention;

[0035] Figure 7 yes Figure 6 BB cross-section diagram;

[0036] Figure 8 The force measurement impedance matching and power distribution circuit of the present invention;

[0037] Fig. 9 It is a radio frequency reading flow chart of the surface acoustic wave temperature sensor of the present invention;

[0038] Among them: 1. Surface acoustic wave temperature sensor array; 2. Shaping tool head; 3. Impedance matching and power distribution circuit board; 4. Force sensitive unit; 5. Grip; 6. Fastening screws; 7. Cover plate; 8. FPC antenna; 9. Copper rod antenna; 10. Single-pole double-throw RF switch; 11. Software radio platform; 12. Host computer; 13. Trapezoidal hole; 14. Force sensitive unit support beam; 15. Force sensitive unit sensitive beam; 16. Surface acoustic wave strain gauge. DETAILED DESCRIPTION

[0039] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings.

[0040] like Figure 1 , Figure 2 As shown, the present invention provides a cutting force and cutting temperature measuring device for solid propellant shaping, comprising

[0041] The force and temperature measuring tool comprises a surface acoustic wave temperature measuring module and a surface acoustic wave force measuring module installed on the shaping tool head 2, and is used for real-time monitoring of the tool cutting temperature and cutting force;

[0042] The radio frequency reader system is connected with the force and temperature measuring tool signal to receive, transmit and process the signal transmitted by the force and temperature measuring tool.

[0043] like Figure 1As shown, the surface acoustic wave temperature measurement module includes a surface acoustic wave temperature sensor array 1, a shaping tool head 2 and a temperature measurement impedance matching and power distribution circuit; the surface acoustic wave temperature sensor array 1 is deposited near the tip of the shaping tool head 2, and the surface acoustic wave temperature sensor array 1 is connected to the temperature measurement impedance matching and power distribution circuit through an extremely fine signal line covered with an insulating film, and the temperature measurement impedance matching and power distribution circuit is connected to the FPC antenna 8.

[0044] Temperature measurement impedance matching and power distribution circuit such as Figure 5 shown.

[0045] The temperature measurement impedance matching and power distribution circuit and the force measurement impedance matching and power distribution circuit are integrated on the impedance matching and power distribution circuit board 3 .

[0046] The impedance matching and power distribution circuit board 3 is mounted on the shaping tool head 2 .

[0047] The FPC antenna 8 is mounted on the handle 5 via the cover plate 7 and the fastening screws 6 .

[0048] The surface acoustic wave temperature sensor array 1 is five surface acoustic wave temperature sensors based on piezoelectric film.

[0049] like Figure 3 , Figure 4 As shown, the surface acoustic wave temperature sensor includes a piezoelectric film, interdigital electrodes and a protective layer. A 2um thick piezoelectric film is deposited at the temperature measurement array in the cutting area of ​​the shaping tool head 2. The interdigital electrodes are arranged between the piezoelectric film and the protective layer. The interdigital electrodes are connected to the temperature measurement impedance matching and power distribution circuit through signal lines.

[0050] Further, the piezoelectric substrate is a metal substrate;

[0051] Furthermore, the piezoelectric film is an AlN or ZnO film;

[0052] Furthermore, the interdigital electrode material is Pt or Al;

[0053] Further, the protective layer is diamond, SiO2 or Al2O3;

[0054] Furthermore, the surface acoustic wave temperature sensor array 1 is a 1×5 array parallel to the tip line of the shaping tool head 2 and at a distance of 5 mm.

[0055] like Figure 1 As shown, the shaping tool head 2 is in the shape of a scraper, and a 1×5 surface acoustic wave temperature sensor array 1 is deposited along the tip of the shaping tool head 2 through micro-nano processing.

[0056] like Figure 1 , Figure 2As shown, the surface acoustic wave force measurement module includes a force sensing unit 4 arranged between the shaping tool head 2 and the handle 5; the force sensing unit 4 is a metal tube as a whole, and the two ends of the force sensing unit 4 are connecting parts, which are external threads and internal threads respectively, for connecting the shaping tool head 2 and the handle 5, and the middle of the force sensing unit 4 is a sensitive part, which is a thin-walled beam structure. The material of the force sensing unit 4 is 40Cr.

[0057] like Figure 6 , Figure 7 As shown, the force measuring sensitive unit 4 is milled with two parallel planes at symmetrical positions on the side wall of the metal tube, and two trapezoidal holes 13 are opened on the two planes. The metal tube is rotated 90° along the axis to open two more trapezoidal holes 13 on the side wall, forming six support beams 14 and two sensitive beams 15. The beams between the trapezoidal holes and the milled planes are sensitive beams 15, and the remaining beams are support beams 14. Two mutually perpendicular surface acoustic wave strain gauges 16 are attached to each sensitive beam 15. The four surface acoustic wave strain gauges 16 are connected to the force measuring impedance matching and power distribution circuit, and then connected to the FPC antenna 8.

[0058] Further, the piezoelectric material of the surface acoustic wave strain gauge 16 is ST tangential quartz sheet;

[0059] Further, the material of the interdigital electrodes of the surface acoustic wave strain gauge 16 is Al;

[0060] Furthermore, the surface acoustic wave strain gauge 16 is packaged in full quartz;

[0061] Furthermore, the force measurement impedance matching and power distribution circuit, such as Figure 8 As shown;

[0062] Furthermore, to avoid crosstalk, based on the changing characteristics of cutting temperature and cutting force, it is preferred that the frequency band of the surface acoustic wave temperature sensor is 2.4 GHz and the frequency band of the surface acoustic wave strain gauge 16 is 433 MHz.

[0063] like Figure 2 As shown, the radio frequency reader system includes a copper rod antenna 9, a single-pole double-throw radio frequency switch 10, a software radio platform 11 and a host computer 12;

[0064] The host computer 12 is connected to the software radio platform 11 by signal. The software radio platform 11 adopts a dual-transmit and dual-receive full-duplex platform. Each pair of receiving end and transmitting end of the software radio platform 11 is isolated by a single-pole double-throw radio frequency switch 10. The software radio platform 11 is connected to the copper rod antenna 9 by signal.

[0065] The software radio platform 11 uses USRP B210, the single-pole double-throw radio frequency switch 10 uses QM-SW-2ST, and the USRP B210 is developed through GNURadio.

[0066] In order to isolate the transmitter and receiver and reduce the crosstalk between the transmitter and receiver, the USRP B210 turns off the receiver, continuously transmits a signal, then turns off the transmitter and continuously receives a signal. However, the USRP B210 needs about 10 microseconds to switch between transmitting and receiving, while the echo signal duration of the surface wave temperature sensor or surface acoustic wave strain gauge is usually about 15 microseconds. If the USRPB210 is used for transceiver switching, the best signal quality of the first 10 microseconds of the echo signal will be lost. Therefore, the USRP B210 is allowed to continuously transmit and receive signals, and the transmitter and receiver are isolated through the QM-SW-2ST RF switch to achieve nanosecond-level transceiver switching and minimize the loss of echo signals. At the same time, the USRP B210 is a dual-transmit and dual-receive full-duplex platform that can access the force measurement module and the temperature measurement module at the same time.

[0067] like Fig. 9 The software radio platform 11 includes

[0068] The transmitting module generates a baseband signal through a signal source. The USRP signal transmitting module generates a carrier signal and mixes it with the baseband signal to obtain an excitation signal and transmit it.

[0069] The receiving module receives the echo signal through the USRP signal receiving module, down-converts it to a baseband signal, performs digital-to-analog conversion on the baseband signal, and transmits it to the host computer for processing. The host computer performs coherent averaging, frequency estimation, and temperature demodulation on the echo signal to achieve temperature measurement.

[0070] The control program of the software radio platform 11 includes a receiving program and a transmitting program. The transmitting program controls the software radio platform 11 to transmit an excitation signal, and the receiving program controls the software radio platform 11 to receive the sensor echo signal and demodulate the temperature / strain. In addition, the control program has a feedback link, that is, after obtaining the resonant frequency, the resonant frequency is fed back to the transmitting flow chart as the next sensor identification excitation frequency.

[0071] The echo signal of the surface wave temperature sensor or the surface acoustic wave strain gauge 16 is mixed with random noise, which will affect the accuracy of subsequent frequency estimation. In order to reduce the influence of random noise, the coherent average of 50 echo signals is performed.

[0072] The receiving program of the receiving module processes the echo signal and demodulates the temperature / strain, including coherent averaging of multiple echo signals to reduce random noise interference. Preferably, coherent averaging of 50 echo signals is performed. The calculation formula is as follows:

[0073]

[0074] in is the echo signal after coherent averaging, y i (t) is the original echo signal, u(t) is the useful signal, n i (t) is a random noise signal.

[0075] like Fig. 9 As shown, the RF reading steps of the SAW temperature sensor are as follows:

[0076] Step 1: The host computer 12 generates a digital baseband signal;

[0077] Step 2: The software radio platform 11 converts the digital baseband signal into digital-to-analog format;

[0078] Step 3: The software radio platform 11 generates a carrier signal and mixes it with the baseband signal to obtain an excitation signal;

[0079] Step 4: the software radio platform 11 transmits an excitation signal through the copper rod antenna 9;

[0080] Step 5: The surface acoustic wave temperature sensor or the surface acoustic wave strain gauge 16 of the shaping tool head 2 is excited to send out an echo signal;

[0081] Step 6: The software radio platform 11 receives the echo signal through the copper rod antenna 9;

[0082] Step 7: the software radio platform 11 down-converts the echo signal to obtain an echo baseband signal;

[0083] Step 8: The software radio platform 11 converts the analog baseband signal into digital form and uploads it to the host computer 12 for storage;

[0084] Step 9: Repeat steps 1 to 8 until 50 echo signals are collected;

[0085] Step 10: The host computer 12 performs coherent averaging and frequency estimation on the 50-segment echo signals;

[0086] Step 11: Repeat steps 1 to 10 until all SAW temperature sensors or SAW strain gauges 16 are read;

[0087] Step 12: The host computer 12 analyzes and demodulates the data to achieve force and temperature measurement.

[0088] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A cutting force and cutting temperature measuring device for solid propellant shaping, characterized in that: include The force and temperature measuring tool comprises a surface acoustic wave temperature measuring module and a surface acoustic wave force measuring module installed on a shaping tool head (2) and used for real-time monitoring of the tool cutting temperature and cutting force; The radio frequency reader system is connected with the force and temperature measuring tool signal to receive, transmit and process the signal transmitted by the force and temperature measuring tool.

2. The cutting force and cutting temperature measuring device for solid propellant shaping according to claim 1, characterized in that: The surface acoustic wave temperature measurement module comprises a surface acoustic wave temperature sensor array (1), a shaping tool head (2) and a temperature measurement impedance matching and power distribution circuit; the surface acoustic wave temperature sensor array (1) is deposited near the tip of the shaping tool head (2), the surface acoustic wave temperature sensor array (1) is connected to the temperature measurement impedance matching and power distribution circuit, and the temperature measurement impedance matching and power distribution circuit is connected to an FPC antenna (8).

3. The cutting force and cutting temperature measuring device for solid propellant shaping according to claim 2, characterized in that: The shaping tool head (2) is in the shape of a scraper, and a surface acoustic wave temperature sensor array (1) is deposited along the tip of the shaping tool head (2) through micro-nano processing.

4. The cutting force and cutting temperature measuring device for solid propellant shaping according to claim 1, characterized in that: The surface acoustic wave force measurement module comprises a force measurement sensitive unit (4) arranged between a shaping tool head (2) and a handle (5); the force measurement sensitive unit (4) is a metal tube as a whole, the two ends of the force measurement sensitive unit (4) are connecting parts for connecting the shaping tool head (2) and the handle (5), and the middle of the force measurement sensitive unit (4) is a sensitive part.

5. The cutting force and cutting temperature measuring device for solid propellant shaping according to claim 1, characterized in that: The force sensing unit (4) of the surface acoustic wave force sensing module is formed by milling two mutually parallel planes at symmetrical positions on the side wall of a metal tube, opening two trapezoidal holes (13) on the two planes, and rotating the metal tube 90 degrees along the axis to open two more trapezoidal holes (13) on the side wall, thereby forming six support beams (14) and two sensitive beams (15), each of which is bonded with two mutually perpendicular surface acoustic wave strain gauges (16), and the four surface acoustic wave strain gauges (16) are connected to a force sensing impedance matching and power distribution circuit, and further connected to an FPC antenna (8).

6. The cutting force and cutting temperature measuring device for solid propellant shaping according to claim 1, characterized in that: The radio frequency reader system comprises a copper rod antenna (9), a single-pole double-throw radio frequency switch (10), a software radio platform (11) and a host computer (12); The host computer (12) is connected to a software radio platform (11) by signal. The software radio platform (11) adopts a dual-transmit and dual-receive full-duplex platform. Each pair of receiving ends and transmitting ends of the software radio platform (11) is isolated by a single-pole double-throw radio frequency switch (10). The software radio platform (11) is connected to a copper rod antenna (9) by signal.

7. The cutting force and cutting temperature measuring device for solid propellant shaping according to claim 6, characterized in that: The software radio platform (11) comprises The transmitting module generates a baseband signal through a signal source, and the transmitting module generates a carrier signal and mixes it with the baseband signal to obtain an excitation signal and transmit it; The receiving module receives the echo signal, down-converts it to a baseband signal, performs digital-to-analog conversion on the baseband signal, and transmits it to the host computer for processing. The host computer performs coherent averaging, frequency estimation, and temperature demodulation on the echo signal to achieve temperature measurement.

8. The cutting force and cutting temperature measuring device for solid propellant shaping according to claim 7, characterized in that: The receiving program of the receiving module performs coherent averaging on 50 echo signals, and the calculation formula is as follows: in is the echo signal after coherent averaging, y i (t) is the original echo signal, u(t) is the useful signal, n i (t) is a random noise signal.

9. A method for measuring cutting force and cutting temperature for solid propellant shaping using the cutting force and cutting temperature measuring device for solid propellant shaping according to claims 1 to 8, characterized in that: The RF reading steps of the surface acoustic wave temperature sensor are as follows: Step 1: The host computer (12) generates a digital baseband signal; Step 2: The software radio platform (11) converts the digital baseband signal into analog digital. Step 3: The software radio platform (11) generates a carrier signal and mixes it with the baseband signal to obtain an excitation signal; Step 4: The software radio platform (11) transmits an excitation signal via the copper rod antenna (9); Step 5: The surface acoustic wave temperature sensor or the surface acoustic wave strain gauge (15) of the shaping tool head (2) is excited to emit an echo signal; Step 6: The software radio platform (11) receives the echo signal through the copper rod antenna (9); Step 7: The software radio platform (11) down-converts the echo signal to obtain an echo baseband signal; Step 8: The software radio platform (11) converts the analog baseband signal into digital form and uploads it to the host computer (12) for storage; Step 9: Repeat steps 1 to 8 until 50 echo signals are collected; Step 10: The host computer (12) performs coherent averaging and frequency estimation on the 50 echo signals; Step 11: Repeat steps 1 to 10 until all the SAW temperature sensors and SAW strain gauges (16) are read; Step 12: The host computer (12) analyzes and demodulates the data to achieve force and temperature measurement.

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