An intelligent ultrasonic tool for a solid propellant robot reshaping system

Abstract

An intelligent ultrasonic cutter for a solid propellant robot shaping system belongs to the technical field of aerospace solid propellant shaping. The cutter combines ultrasonic cutting technology and an intelligent sensing system to provide force feedback and temperature feedback for robot solid propellant shaping, greatly improving machining precision and safety. The front end of the amplitude lever is fixed with a cutter head, the rear end of the amplitude lever is connected with a force measuring base, a sensitive element is fixed between the amplitude lever and the force measuring base through pre-tightening force during installation, a temperature measuring element is installed on the cutter head, and an excitation element is installed on the amplitude lever. The invention reduces the risk of cutter slip and collision caused by excessive cutting force and avoids safety hazards during the cutting process. The compactness and high integration of the overall design of the invention make the cutter have high flexibility and operation convenience in the robot solid propellant grain shaping process, and can meet the needs of precision machining and long-time high-load operation.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aerospace solid propellant shaping technology, and particularly relates to an intelligent ultrasonic cutter for a solid propellant robot shaping system. BACKGROUND

[0002] Solid rocket engine as a core equipment of space exploration, compared with liquid and gas rocket engine, has the advantages of simple structure, high stability and excellent thrust-to-weight ratio. Solid propellant has the characteristics of viscoelasticity, easy to crack, easy to burn and easy to explode, and its shaping precision is a key link to ensure its stability and reliability. The current propellant shaping methods mainly include manual shaping and mechanical shaping. In "an ultrasonic auxiliary shaping cutter for solid fuel" (application number 201810705611.4), an ultrasonic auxiliary shaping cutter for manual use is proposed for solid fuel. However, with the increasing size and complexity of solid propellant, the advantages of robot replacing manual shaping are becoming more and more obvious, and it has become one of the mainstream development directions. Robots have the advantages of high flexibility, large working space, high precision and low cost, and can freely replace end tools to complete processing, welding, handling and other types of work. Cooperating with the solid fuel shaping cutter, it can replace manual work to complete the shaping and cutting of large-size solid propellant, greatly ensuring the safety of workers and reducing labor intensity. However, there are few solid propellant shaping cutters for robot end at present, and because the robot itself cannot perceive the force and temperature during propellant shaping, it can only cut slowly with conservative parameters, cannot automatically adjust the cutting parameters according to the real-time state of the cutter, and is difficult to realize efficient and large-scale production, which seriously limits the improvement of production efficiency and manufacturing capacity.

[0003] Because of the obvious viscoelastic characteristics of solid propellant materials, elastic and plastic deformation is easy to occur during cutting processing, and the processing precision and efficiency are difficult to guarantee. The ultrasonic cutter converts electrical energy into mechanical energy through an ultrasonic transducer, amplifies the amplitude of ultrasonic vibration through an amplitude transformer, and excites the cutter head to swing back and forth in a specific direction at high frequency. Using ultrasonic cutter to process viscoelastic materials has the advantages of high cutting precision, no material deformation, small cutting force, high cutting efficiency, and good cutting edge, and is widely used in the processing of rubber, silicone and other viscoelastic materials. Therefore, using ultrasonic cutter to shape and process solid propellant can further improve cutting efficiency, reduce cutting difficulty and improve shaping precision.

[0004] Therefore, in view of the need for using robots to shape and process solid propellant, a cutter that takes into account ultrasonic processing, temperature monitoring and cutting force monitoring is needed. SUMMARY

[0005] The intelligent ultrasonic cutter for the solid propellant robot shaping system is provided, which combines ultrasonic cutting technology and an intelligent sensing system, and provides force feedback and temperature feedback for robot solid propellant shaping, and greatly improves processing precision and safety.

[0006] The technical scheme adopted by the present application is:

[0007] The intelligent ultrasonic cutter for the solid propellant robot shaping system comprises a robot flange adapter plate, a force measuring base, an amplitude-varying rod, a cutter head, an excitation element, a sensitive element and a temperature measuring element.

[0008] Compared with the prior art, the present application has the following beneficial effects:

[0009] The present application can provide force feedback and temperature feedback for robots during solid propellant grain shaping, thereby improving shaping precision and safety.

[0010] Compared with the prior art, the solid propellant shaping intelligent ultrasonic cutter has the following advantages:

[0011] (1) The cutting force is greatly reduced;

[0012] Compared with traditional mechanical cutters, the ultrasonic auxiliary shaping cutter effectively reduces the required cutting force through high-frequency vibration. In traditional cutting, the contact between the cutter and the workpiece is continuous, while ultrasonic vibration makes the contact between the cutter and the workpiece intermittent, reducing the compressive stress of the material. This feature significantly reduces the risk of cutter slip and collision caused by excessive cutting force, avoiding safety hazards during the cutting process. In addition, since the cutter can be easily installed on a robot mechanical arm, stable and efficient cutting can be achieved in an automated environment, further reducing the burden of manual operation.

[0013] (2) Compact structure and high integration;

[0014] Various components such as amplitude rods, excitation elements, sensitive elements, temperature measuring elements, etc. are integrated inside the cutter through ingenious layout and compact design, making full use of limited space to ensure efficient operation of the system. The cutter adopts modular design, facilitating assembly and maintenance of various components, and realizes real-time monitoring of cutting force and temperature through an efficient sensing and control system, improving machining precision and safety. The compactness and high integration of the overall design make the cutter highly flexible and easy to operate during the robot solid propellant grain shaping process, meeting the needs of precision machining and long-term high-load operation.

[0015] (3) Modular design for easy maintenance and replacement;

[0016] The cutter head adopts an L-shaped bending structure design with modular characteristics, facilitating installation, maintenance and replacement. This design makes the cutter more flexible to use, reduces damage caused by improper operation, and improves overall production efficiency. Through automated operation of the mechanical arm, the service life of the cutter can be maximized, reducing damage caused by human operation.

[0017] (4) Accurate monitoring of force and temperature during machining;

[0018] The ultrasonic wave assisted shaping cutter of the present application can monitor the changes of cutting force and temperature in real time, effectively avoid the damage of cutter or deformation of workpiece caused by excessive cutting force, and timely adjust the temperature to prevent the change of physical properties of propellant due to high temperature during machining. This precise force and temperature feedback system not only improves the machining accuracy, but also greatly improves the safety of the machining process, especially in high-risk industries to replace manual operation, reducing the risk and safety hazards of human intervention. The intelligent cutter provides strong support for robot automation operation, ensuring that the solid propellant shaping task can still be completed stably and efficiently in a long-term, high-load working environment, significantly improving the safety and stability of the overall operation. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural schematic diagram of the present application;

[0020] Figure 2 is a structural schematic diagram of the sensitive element of the present application;

[0021] Figure 3 is a structural schematic diagram of the cutter head of the present application;

[0022] Figure 4 is a schematic diagram of the installation state of the present application Figure 1 ;

[0023] Figure 5 is a schematic diagram of the installation state of the present application Figure 2 ;

[0024] 1, inner hexagonal screw one; 2, robot flange adapter plate; 3, right half shell; 4, force measuring base; 5, inner hexagonal screw two; 6, lead connector; 7, amplitude bar; 8, inner hexagonal screw three; 9, left half shell; 10, tool bit; 11, hex head bolt; 12, excitation element; 121, piezoelectric ceramic one; 13, sensitive element; 131, force measuring boss; 132, PCB electrode sheet; 133, piezoelectric ceramic two; 134, circular ring electrode sheet; 135, zirconia insulating sheet; 14, shell. DETAILED DESCRIPTION

[0025] In order to better understand the purpose, structure and function of the present application, the present application is described in further detail below in combination with the drawings.

[0026] As shown in Figures 1-5 The present application provides an intelligent ultrasonic tool for a solid propellant robot shaping system, which comprises a robot flange adapter plate 2, a force measuring base 4, an amplitude bar 7, a tool bit 10, an excitation element 12, a sensitive element 13 and a temperature measuring element; the front end of the amplitude bar 7 is fixed with the tool bit 10 through a hex head bolt 11, and the rear end of the amplitude bar 7 is connected with the force measuring base 4 through an inner hexagonal screw two 5, the upper end of the force measuring base 4 is connected with the robot flange adapter plate 2 through an inner hexagonal screw one 1, the sensitive element 13 is fixed between the amplitude bar 7 and the force measuring base 4 through the pre-tightening force during installation, the temperature measuring element is installed on the tool bit 10, and the excitation element 12 is installed on the amplitude bar 7.

[0027] The excitation element 12 comprises two pieces of piezoelectric ceramic one 121 material, which are respectively installed through two opposite planes of the amplitude bar 7, the piezoelectric ceramic one 121 is connected through the same excitation signal line, and the excitation signal lines of the positive charge plane and the negative charge plane are respectively connected with the lead connector 6;

[0028] The sensitive element 13 comprises two force measuring units, which are symmetrically arranged and separated from the shell and the amplitude bar 7 by a zirconia insulating sheet 135, and the charge signals measured by the force measuring units are transmitted out through the lead connector 6;

[0029] The temperature measuring element is a thermocouple array, which is installed at the slotted part of the tool bit 10, passes through the center hole of the amplitude bar 7 through the reserved installation slot, and is connected to the lead connector 6;

[0030] As shown in Figure 1As shown, the amplitude horn 7 is provided with a shell 14, the amplitude horn 7 is located in the center of the shell 14, the excitation element 12 is located between the amplitude horn 7 and the shell 14, the shell 14 is composed of a left half shell 9 and a right half shell 3, the left half shell 9 and the right half shell 3 are both two half cuboids, and the left half shell 9 and the right half shell 3 are connected to the left and right end faces of the force measuring base 4 by the socket head cap screws 8 to complete the combination and form a cuboid shape. The end face of the rear end of the shell 14 has a wiring plug for leading out the data line bundle; the end face of the front end of the shell 14 has a through slot of the amplitude horn 7, the ultrasonic amplitude horn 7 can be installed in the through slot, and the shell 14 and the amplitude horn 7 are sealed by a sealing ring; the upper end of the shell 14 has a through slot of the force measuring base 4, the force measuring base 4 can be installed in the through slot and fixed by interference fit. The shell 14 and the force measuring base 4 are sealed by a sealing ring.

[0031] The shell 14 has two layers, which are an inner layer of aluminum alloy shell and an outer layer of insulating explosion-proof shell. The thickness of the aluminum alloy shell is greater than 8 mm, and good grounding is performed.

[0032] As shown in Figure 1 , Figure 3 The tool bit 10 adopts an L-shaped bending structure, the tail end of the tool bit 10 is a multi-hole mounting part which is fixed to the front end of the amplitude horn 7 by four hexagonal head bolts 11, and the front end of the tool bit 10 is a cutting edge with a certain inclination angle.

[0033] The cutting edge part of the tool bit 10 is used for cutting workpieces. The design of the tool bit 10 enables the cutting edge to flexibly adhere to the surface of the workpiece for precise cutting, and the inclination angle design optimizes the cutting force and the friction coefficient, improves the cutting efficiency and reduces the friction.

[0034] As shown in Figure 3 The bottom plane of the cutting edge is arranged with five temperature measuring points, the front three temperature measuring points are close to the tool tip, and the rear two temperature measuring points are slightly away from the tool tip, forming a temperature measuring array, the temperature measuring element is a thermocouple array, which is installed in the slot of the cutting edge, passes through the center hole of the amplitude horn 7, and is connected to the lead connector 6; specifically, the thermocouple filaments are buried in the root-shaped slots at the bottom of the cutting edge, pass through the center of the tail end of the tool bit 10 and out of the center hole of the amplitude horn 7, the slots on the tool bit 10 are radially and symmetrically distributed, there are five slot lines, which expand from the front tip of the tool bit 10 along the surface, the slot lines are uniformly arranged and equally spaced from each other. The shape of the slot is an elongated groove, which is consistent with the geometric shape of the tool bit 10 and naturally extends along the arc, forming a certain angle with the edge of the tool bit 10. This design ensures the functionality and structural symmetry of the slot, and enhances the overall appearance and performance of the tool bit 10.

[0035] As shown in Figure 1As shown, the amplitude lever 7 is a positive quadrangular prism boss structure, and a cylindrical through hole is arranged in the center, which is a through hole for the data line. The thermocouple for the temperature measuring element passes through the tool bit 10 to the connector plug. The rear end of the amplitude lever 7 has a circular ring boss, and the surface of the circular ring boss is a matching surface that needs to be finely ground, which is used for the installation of the sensitive element 13.

[0036] The excitation element 12 is two rectangular piezoelectric ceramic stacks pasted on both sides of the amplitude lever 7. The positive poles of the two piezoelectric ceramics are in the same direction, and when an alternating current acts, the amplitude lever 7 is excited to bend and vibrate with the same phase.

[0037] As shown in the figure, Figure 2 The sensitive element 13 includes two force measuring units, which together complete the measurement of three-way cutting force. The two force measuring units are symmetrically distributed and include force measuring bosses 131, PCB electrode sheets 132, piezoelectric ceramics 133, circular ring electrode sheets 134, and zirconia insulating sheets 135 arranged from the center to the two ends. The negative pole of the piezoelectric ceramic 133 is in contact with the PCB electrode sheet 132, and the positive pole of the piezoelectric ceramic 133 is in contact with the circular ring electrode sheet 134.

[0038] The two force measuring units are separated from the shell 14 and the amplitude lever 7 by the zirconia insulating sheet 135. The measured charge signal is transmitted out through the lead connector 6.

[0039] As shown in the figure, Figure 2 The two force measuring bosses 131 are symmetrically integrated on both sides. The outer surface of the force measuring boss 131 is provided with four circular bosses in a rhombic distribution for applying pressure to the piezoelectric ceramic 133. The force measuring boss 131 is a stainless steel force measuring element,

[0040] The center area of the PCB electrode sheet 132 is designed with an opening. The PCB electrode sheet 132 is a single-sided circuit board printed with four conductive areas in a rhombic distribution on the side in contact with the piezoelectric ceramic 133, which can effectively conduct the charge change generated by the piezoelectric ceramic, thereby realizing the output of the electric signal. The protrusions of the force measuring boss 131 correspond one-to-one to the centers of the four conductive areas, which are slightly higher than the surrounding insulating areas and are connected to the four circular pads arranged in the center of the PCB electrode sheet 132, forming a charge conduction path to ensure that the charge change of the piezoelectric ceramic can be efficiently output to the external circuit.

[0041] The piezoelectric ceramic 133 is in the shape of a ring, and has different coating shapes on two surfaces. One surface in contact with the circular electrode sheet 134 is a complete silver plating coating, forming a continuous and uniform conductive coating to realize efficient conduction of electric charges. The other surface in contact with the PCB electrode sheet 132 is a silver plating coating covering only four conductive areas of the rhombic distribution of the PCB electrode sheet 132, which is a local silver plating layer and presents four independent arc-shaped conductive areas corresponding to the conductive areas of the PCB electrode sheet 132. The arc-shaped conductive areas are distributed in a cross symmetry and are separated by the non-silver plating areas, and are used for accurately sensing and conducting the electric charge signals generated by the stainless steel force measuring boss 131. The central opening design facilitates the passage of wires.

[0042] The force measuring unit is characterized in that the circular electrode sheet 134 is in contact with the silver full silver plating layer of the piezoelectric ceramic 133, the local silver plating layer of the piezoelectric ceramic 133 is in contact with the non-full insulation coating of the PCB electrode sheet 132, and one surface of the full insulation coating of the PCB electrode sheet 132 is in contact with the force measuring boss 131. At the same time, the four symmetrically distributed arc-shaped conductive areas of the piezoelectric ceramic 133, the four symmetrically distributed conductive areas of the PCB electrode sheet 132, and the four symmetrically distributed protrusions of the force measuring boss 131 are accurately aligned in the axial direction during installation.

[0043] The measurement method of three-direction cutting force is as follows:

[0044] Suppose that one of the signals output by the PCB electrode sheet 132 is F1, F2, F3, and F4 in clockwise order as viewed from the force measuring base 4 after passing through the charge amplifier, and the other signal output by the PCB electrode sheet 132 is F5, F6, F7, and F8 in clockwise order as viewed from the force measuring base 4 after passing through the charge amplifier. The three-direction force on the tool bit 10 can be represented as:

[0045] F x = F2 - F4 + F6 - F8

[0046] F y = F1 - F3 + F5 - F7

[0047] F z = F1 + F2 + F3 + F4 + F5 + F6 + F7 + F8.

[0048] All lead wire welding points in the sensitive element 13 are arranged at the center of the force measuring unit, and the lead wires of the sensitive element 13, the excitation element 12, and the temperature measuring element are led out through the through holes to the lead wire connector 6 and connected with the rear-end circuit.

[0049] The signals of the sensitive element 13 are output by two PCB electrode sheets 132 as four signals, respectively, and are connected with the lead wire connector 6 through the through holes of the force measuring base 4 by signal lines;

[0050] The signal of the temperature measuring element is transmitted from the thermocouple through the center hole of the amplitude transformer 7 in the reserved installation slot, and then passes through the center of the sensitive element 13 and the through hole of the force measuring base 4 to be connected to the lead connector 6.

[0051] The temperature measuring element is a thermocouple located at the slot of the cutter head 10. It passes through the reserved installation slot and the center hole of the amplitude transformer 7, and then passes through the center of the sensitive element 13 to be connected to the lead connector 6. When the temperature collected by the sensor of the temperature measuring element exceeds the set value required by the process, the temperature control module terminates the operation.

[0052] The signal of the excitation element 12 is inputted by the lead connector 6 through the through hole of the force measuring base 4 and connected to the plane of the corresponding excitation unit through the same excitation signal line;

[0053] like Figure 1 As shown, the excitation element 12 includes two piezoelectric ceramics 121, and the two piezoelectric ceramics 121 are respectively attached to the left and right planes of the amplitude transformer 7. The normal direction of the two relative planes is the same as the cutting direction of the tool head 10, and the positive charge planes of the two piezoelectric ceramics 121 after polarization are in the same direction. Therefore, the cutting force direction requirements required for the tool head 10 during processing and the frequency degeneracy of the two bending vibration modes can be ensured. When driven by a high-frequency voltage with the same phase amplitude, the two piezoelectric ceramics 121 excite the amplitude transformer 7 to generate ultrasonic vibrations. The amplitude transformer 7 amplifies the amplitude and transmits it to the tool head 10, causing the tool tip to vibrate ultrasonically along the normal direction of the two piezoelectric ceramics 121.

[0054] like Figure 1 As shown, threaded holes are reserved on the left and right sides of the upper end of the force measuring base 4 for fixing the left half shell 9 and the right half shell 3. The rear end of the force measuring base 4 is connected to the amplitude rod 7 through the hexagon socket screw 5 to provide pre-tightening force for the piezoelectric ceramic force measuring crystal group, and a through hole is reserved for the wire to pass through.

[0055] The assembly order of the intelligent ultrasonic tool of the solid propellant robot plastic surgery system is as follows: first, use the hexagon socket screw 2 5 to fix the order of the two force measuring units contained in the sensitive element 13 between the force measuring base 4 and the amplitude rod 7, and pass the corresponding sensitive element 13, excitation element 12, and temperature measuring element leads through the through hole of the force measuring base 4; fix the cutter head 10 with the thermocouple installed by the hexagon head bolt 11; connect all the leads to the lead connector 6, and then fix the left half shell 9 and the right half shell 3 to the amplitude rod 7 and the force measuring base 4 by the hexagon socket screw 3 8; finally, fix the robot flange adapter plate 2 to the shell 14 by the hexagon socket screw 1, and connect the external wires.

[0056] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by 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 to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. An intelligent ultrasonic tool for a solid propellant robotic shaping system, characterized by: The robot comprises a flange adapter plate (2), a force measuring base (4), an amplitude changing rod (7), a cutter head (10), an excitation element (12), a sensitive element (13) and a temperature measuring element; the front end of the amplitude changing rod (7) is fixed to the cutter head (10), the rear end of the amplitude changing rod (7) is connected to the force measuring base (4), the upper end of the force measuring base (4) is connected to the robot flange adapter plate (2), the sensitive element (13) is fixed between the amplitude changing rod (7) and the force measuring base (4), the temperature measuring element is installed on the cutter head (10), the excitation element (12) is installed on the amplitude changing rod (7), A housing (14) is provided outside the amplitude changing rod (7), the excitation element (12) is located between the amplitude changing rod (7) and the housing (14), and the rear end surface of the housing (14) has a wiring plug (6) for leading out a data harness; the upper end surface of the housing (14) has a slot for the amplitude changing rod (7), and the rear end of the housing (14) has a slot for the force measuring base (4). The cutter head (10) adopts an L-shaped bending structure, the end of the cutter head (10) is a multi-hole mounting portion, the end of the cutter head (10) is fixed to the front end of the amplitude rod (7), and the front end of the cutter head (10) is a blade with a certain inclination angle. The bottom plane of the blade is provided with a plurality of temperature measuring points to form a temperature measuring array. The temperature measuring element is a thermocouple array. The thermocouple filaments are buried in the slots at the bottom of the blade and are led out through the center of the end of the blade head (10) to the center hole of the amplitude rod (7). The slots on the blade head (10) are radially symmetrically distributed. There are five slot lines in total, which extend from the front end tip of the blade head (10) to the rear along the surface. The slot lines are evenly arranged. The horn (7) is a regular quadrangular prism boss structure with a cylindrical through hole in the center. The thermocouple for temperature measurement passes from the cutter head (10) to the wiring plug. The rear end of the horn (7) has a circular boss. The surface of the circular boss is used for the installation of the sensitive element (13). The sensitive element (13) includes two force measuring units, which together complete the measurement of the three-dimensional cutting force. The two force measuring units are symmetrically distributed and include a force measuring boss (131), a PCB electrode sheet (132), a second piezoelectric ceramic (133), a circular electrode sheet (134), and a zirconium oxide insulating sheet (135) distributed in sequence from the center to both ends. The negative electrode of the second piezoelectric ceramic (133) is in contact with the PCB electrode sheet (132), and the positive electrode of the second piezoelectric ceramic (133) is in contact with the circular electrode sheet (134).

2. The intelligent ultrasonic tool for a solid propellant robotic reshaping system according to claim 1, characterized in that: The two force measuring bosses (131) are symmetrically integrated on both sides, and the outer surface of the force measuring boss (131) is provided with four circular bosses for applying pressure to the piezoelectric ceramic 2 (133); The PCB electrode sheet (132) is printed on a single side of the circuit board, the side in contact with the force measuring boss (131) is an insulating side, and the side in contact with the piezoelectric ceramic (133) is printed with four conductive areas, the protrusions of the force measuring boss (131) correspond one-to-one to the centers of the four conductive areas of the PCB electrode sheet (132), and the conductive areas are connected to four circular pads provided in the center of the PCB electrode sheet (132); The second piezoelectric ceramic (133) is annular, and the side in contact with the annular electrode sheet (134) is completely silver-plated, and the side in contact with the PCB electrode sheet (132) is silver-plated and covers four conductive areas of the PCB electrode sheet (132).

3. The intelligent ultrasonic tool for a solid propellant robotic reshaping system according to claim 1, characterized in that: The three-way cutting force is measured as follows: Assume that the signal output by the PCB electrode sheet (132) after passing through the charge amplifier is recorded in clockwise order from the direction of the force measuring base (4) as follows: 、 、 、 The signal outputted by the other PCB electrode sheet (132) is recorded as follows in clockwise order from the direction of the force measuring base (4) after passing through the charge amplifier: 、 、 、 , it can be measured that the three-axis force on the cutter head (10) can be expressed as: 。 4. The intelligent ultrasonic tool for a solid propellant robotic reshaping system according to claim 1, characterized in that: The excitation element (12) comprises two piezoelectric ceramics (121), the two piezoelectric ceramics (121) being respectively attached to the left and right planes of the amplitude transformer (7), and the positive charge planes of the two piezoelectric ceramics (121) after polarization are oriented in the same direction.

5. The intelligent ultrasonic tool for a solid propellant robotic reshaping system according to claim 1, characterized in that: Threaded holes are reserved on the left and right sides of the upper end of the force measuring base (4) for fixing the left half shell (9) and the right half shell (3) of the shell, and the rear end of the force measuring base (4) is connected to the amplitude rod (7).

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