A low-power beat wave driving method for ultrasonic-assisted drilling and sampling devices

Abstract

This invention discloses a low-power traveling wave driving method for an ultrasonic-assisted drilling sampling device, comprising: a drive control system supplying a set of high-frequency sine wave signals and a set of low-frequency sine wave signals, superimposing them to form a new beat frequency wave signal; driving an ultrasonic transducer through the beat frequency signal, causing mechanical deformation of the electroceramic plate of the ultrasonic transducer, thereby exciting the longitudinal vibration of the ultrasonic drill; the traveling wave generated by the superposition of the two sets of sine waves increases the maximum amplitude while keeping the average power of the ultrasonic drill constant, further improving the efficiency of ultrasonic-assisted particle movement, reducing the critical speed of the spindle, increasing the sampling efficiency of soil particles, and reducing the overall energy consumption of the system; in addition, a passive damping section is set at the non-excitation end of the ultrasonic drill rod to absorb the traveling wave transmitted from the excitation end and avoid the generation of standing waves.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic-assisted drilling and sampling, and specifically to a low-power drive control method for an ultrasonic-assisted drilling and sampling device. Background Technology

[0002] With the continuous development of deep space exploration technology, asteroid exploration has gradually become a research hotspot. Because asteroids contain geological information from the early stages of the solar system's formation, studying them helps in understanding the formation and evolution of the solar system. In existing asteroid exploration missions, obtaining asteroid rock samples has become an important objective of deep space exploration.

[0003] Drilling sampling is an important method for obtaining rock samples. Current drilling sampling methods mainly rely on traditional sampling equipment powered by electromagnetic motors. Typically, as the drilling depth increases, the required drilling pressure and driving torque of the sampling device also increase, while soil particle accumulation can occur. However, the detector's payload and energy are limited, making it difficult to meet the ever-increasing drilling pressure and power requirements of traditional sampling equipment.

[0004] To address the problems encountered during drilling and sampling, researchers proposed an ultrasonic-assisted drilling and sampling device. This device utilizes ultrasonic vibration to assist the drill rod in transporting soil particles, effectively improving the transport efficiency. However, a single sinusoidal wave excitation does not efficiently utilize the energy of the ultrasound. Therefore, a drive control method for the ultrasonic-assisted drilling and sampling device is proposed. Summary of the Invention

[0005] To address the above problems, this invention provides a low-power drive control method for ultrasonic-assisted drilling and sampling, which can further improve the transport efficiency of soil particles and reduce energy consumption during the sampling process.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] S1. Input a set of high-frequency sine wave signals and a set of low-frequency sine wave signals, superimpose them to form a new beat frequency wave signal, and use the beat frequency signal to excite the ultrasonic transducer. The piezoelectric ceramic sheet of the ultrasonic transducer undergoes mechanical deformation, thereby exciting the longitudinal vibration of the ultrasonic drill.

[0008] The average power of the ultrasonic drill is adjusted by regulating the discontinuity period and discontinuity time of the high-frequency and low-frequency sinusoidal signals; the discontinuity period T1 and continuous time T2 of the high-frequency and low-frequency sinusoidal signals are given by the following formulas:

[0009]

[0010] Where f1 is the frequency of the low-frequency sine wave signal and f2 is the frequency of the high-frequency sine wave signal;

[0011] The low-frequency sine wave signal is determined based on the overall system structure, and its frequency is calculated using the following formula:

[0012]

[0013] Where k is the equivalent stiffness of the overall system, and m is the particle mass; the expression for the force between the particle and the ultrasonic drill during low-frequency vibration is:

[0014]

[0015] Where, k c δ represents the equivalent contact stiffness between the particle and the drill surface, and δ represents the static deformation of the particle.

[0016] The high-frequency sinusoidal signal is determined based on the overall system structure, and the frequency calculation formula is as follows:

[0017]

[0018] Where L is the effective length of the sample, E is the dynamic elastic modulus of the material, and ρ is the density of the material;

[0019] The vibration of an ultrasonic drill consists of two sets of superimposed sine waves forming a beat wave. The two sets of sine waves are:

[0020]

[0021] Where A1 and A2 are the amplitudes of the two sets of sine waves, and ω1 and ω2 are the angular velocities of the two sets of sine waves. and Let be the initial phase of the two sets of sine waves; the expressions for the two sets of sine waves are:

[0022]

[0023] The two sets of sine waves superimposed are:

[0024]

[0025] Among them, A 12 Let be the beat frequency amplitude, which varies over time. The expression for the amplitude is as follows:

[0026]

[0027] S2. The drive control system provides DC voltage to the spindle rotary motor to drive the spindle rotary motor. The output end of the motor is connected to the ultrasonic drill through the transmission shaft and the torque is transmitted through the key connection to drive the ultrasonic drill to rotate.

[0028] Optionally, the ultrasonic drill includes a piezoelectric ultrasonic transducer and a helical rod, which are connected by threads.

[0029] Optionally, to improve the ultrasonic-assisted drilling sampling effect, a passive damping structure is installed at the other end of the ultrasonic drill rod as a vibration absorber to prevent the formation of standing wave nodes due to traveling wave reflection. In this embodiment, polyoxymethylene (POM) is used as the passive damping material. The transmission of traveling waves ensures that the ultrasonic-assisted drilling sampling effect is the same on the rod, and the presence of standing wave nodes will not affect the ultrasonic-assisted drilling sampling effect.

[0030] Optionally, the spindle rotation motor is a DC electromagnetic motor, and the motor power is:

[0031] P = T × ω

[0032] Based on the forces acting on the particle, the equation of motion for the particle is:

[0033]

[0034] Among them, f b cos(α+β)=T / R=μ b mω 2 R,f a =μ a mg cosα,T is the torque of the main spindle motor, f b f is the frictional force between the particle and the pore wall. a μ is the frictional force between the particle and the drill surface. a μ is the coefficient of friction between the particle and the drill surface. b ω is the coefficient of friction between the particle and the borehole, α is the angular velocity of the ultrasonic drill, α is the helix angle of the ultrasonic drill, β is the helix angle of the actual trajectory of the particle, R is the radius of the ultrasonic drill rod, m is the mass of the particle, and g is the acceleration due to gravity.

[0035] Optionally, to ensure that soil particles can be properly discharged, the particle motion equation must satisfy: At the critical speed, the following conditions must be met: Right now:

[0036] T / R+Fsinα-mg sinα-μ a mg cosα=0

[0037] The ultrasonic drill is excited by a sinusoidal signal of ultrasonic frequency to generate longitudinal vibration. Waves on the ultrasonic drill are reflected and superimposed to form standing waves. According to the Clani effect of ultrasound on particles, particles will aggregate near the node under the influence of ultrasound, where the energy transferred to the particles is lowest. The auxiliary effect of ultrasound on drilling and sampling will exhibit periodic fluctuations, with the particle energy at the node being zero.

[0038] Furthermore, to enhance the effectiveness of ultrasonic-assisted drilling, a set of high-frequency sine wave signals and a set of low-frequency sine wave signals are applied to the ultrasonic drill through the drive control system. The high-frequency sine wave signals and the low-frequency sine wave signals drive the piezoelectric ceramic sheet to undergo periodic mechanical deformation, thereby exciting the longitudinal vibration of the ultrasonic drill.

[0039] Optionally, the frequency calculation for the ultrasonic drill involves several factors, including the material's dynamic elastic modulus, density, and sample geometry. This frequency, near the ultrasonic drill's resonant frequency, can excite the ultrasonic drill's third-order longitudinal vibration.

[0040] The frequency of an ultrasonic drill can be calculated using the following formula:

[0041]

[0042] Where L is the effective length of the sample, E is the dynamic elastic modulus of the material (Pa), and ρ is the density of the material (kg / m³). 3 ).

[0043] Ultrasonic vibrations can create a cavitation layer between the particles and the drill surface, reducing the coefficient of friction μ between the particles and the drill surface. a This reduces the frictional resistance encountered by particles during their ascent.

[0044] Beneficial effects:

[0045] This invention discloses a low-power traveling wave driving method for an ultrasonic-assisted drilling sampling device, comprising: a drive control system supplying a set of high-frequency sine wave signals and a set of low-frequency sine wave signals, superimposing them to form a new beat frequency wave signal; driving an ultrasonic transducer through the beat frequency signal, causing mechanical deformation of the electroceramic plate of the ultrasonic transducer, thereby exciting the longitudinal vibration of the ultrasonic drill; the traveling wave generated by the superposition of the two sets of sine waves increases the maximum amplitude while keeping the average power of the ultrasonic drill constant, further improving the efficiency of ultrasonic-assisted particle movement, reducing the critical speed of the spindle, increasing the sampling efficiency of soil particles, and reducing the overall energy consumption of the system; in addition, a passive damping section is set at the non-excitation end of the ultrasonic drill rod to absorb the traveling wave transmitted from the excitation end and avoid the generation of standing waves. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of the driving method provided by the present invention;

[0048] Figure 2 This is a schematic diagram of an ultrasonic drill provided by the present invention;

[0049] Figure 3 A simplified force diagram of the particle model provided by this invention;

[0050] Figure 4 This is a schematic diagram of the superposition of two sets of signals provided by the present invention;

[0051] Figure 5 This is a schematic diagram of the beat frequency wave provided by the present invention;

[0052] Figure 6 This is a schematic diagram of a periodic discontinuous sine wave provided by the present invention. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Reference Figure 1 and Figure 2 This embodiment provides a drive control method for ultrasonic-assisted drilling and sampling, including the following steps:

[0055] First, a set of high-frequency sine wave signals and a set of low-frequency sine wave signals are input and superimposed to form a new beat frequency wave signal. The beat frequency signal is used to excite the ultrasonic transducer, and the piezoelectric ceramic sheet of the ultrasonic transducer undergoes mechanical deformation, thereby exciting the longitudinal vibration of the ultrasonic drill.

[0056] Secondly, the drive control system supplies DC voltage to the spindle rotary motor to drive the spindle rotary motor. The output end of the motor is connected to the ultrasonic drill through the transmission shaft, and the torque is transmitted through the key connection to drive the ultrasonic drill to rotate.

[0057] In this embodiment, the ultrasonic drill includes a piezoelectric ultrasonic transducer and a spiral rod, which are connected by threads.

[0058] In this embodiment, the spindle rotary motor is a DC electromagnetic motor, and the motor power is:

[0059] P = T × ω

[0060] like Figure 3 As shown, based on the forces acting on the particle, the equation of motion for the particle is:

[0061]

[0062] Among them, f b cos(α+β)=T / R=μ b mω 2 R,f a =μ a mg cosα, T is the torque of the main spindle motor, f b f is the frictional force between the particle and the pore wall. a μ is the frictional force between the particle and the drill surface. a μ is the coefficient of friction between the particle and the drill surface. b ω is the coefficient of friction between the particle and the borehole, α is the angular velocity of the ultrasonic drill, α is the helix angle of the ultrasonic drill, β is the helix angle of the actual trajectory of the particle, R is the radius of the ultrasonic drill rod, m is the mass of the particle, and g is the acceleration due to gravity.

[0063] To ensure proper discharge of soil particles, the equation of motion for the particles must satisfy: At the critical speed, the following conditions must be met: Right now:

[0064] T / R+Fsinα-mg sinα-μ a mg cosα=0

[0065] This implementation uses a 20kHz sinusoidal wave signal to excite an ultrasonic drill to generate longitudinal vibration. Waves on the ultrasonic drill are reflected and superimposed to generate standing waves. Based on the Clani effect of ultrasound on particles, particles will aggregate near the node under the influence of ultrasound, where the energy transferred to the particles is lowest. The auxiliary effect of ultrasound on drilling and sampling will exhibit periodic fluctuations, with the particle energy at the node being zero.

[0066] Furthermore, to enhance the ultrasonic-assisted drilling sampling effect, a passive damping structure is installed at the other end of the ultrasonic drill rod as a vibration absorber to prevent traveling wave reflection from forming a stationary state. In this implementation, polyoxymethylene (POM) is used as the passive damping material. Figure 2 As shown, the transmission of the traveling wave ensures that the ultrasonic-assisted drilling and sampling function is the same on the rod, and the presence of standing wave nodes will not affect the ultrasonic-assisted drilling and sampling function.

[0067] Furthermore, to enhance the effectiveness of ultrasonic-assisted drilling, the drive control system applies a set of high-frequency sine wave signals and a set of low-frequency sine wave signals to the ultrasonic drill. The high-frequency and low-frequency sine wave signals drive the piezoelectric ceramic sheet to undergo periodic mechanical deformation, thereby stimulating the longitudinal vibration of the ultrasonic drill.

[0068] In this embodiment, the frequency of the excitation voltage is determined to be 20kHz based on the structural dimensions and materials of the ultrasonic drill. This frequency is near the resonant frequency of the ultrasonic drill and can excite the third-order longitudinal vibration of the ultrasonic drill.

[0069] The frequency of an ultrasonic drill can be calculated using the following formula:

[0070]

[0071] Where L is the effective length of the sample, E is the dynamic elastic modulus of the material (Pa), and ρ is the density of the material (kg / m³). 3 ).

[0072] In this embodiment, ultrasonic frequency vibration can generate a cavitation layer between the particle and the drill surface, reducing the friction coefficient μ between the particle and the drill surface. a This reduces the frictional resistance encountered by particles during their ascent.

[0073] In this embodiment, the low-frequency signal is determined to have an excitation voltage frequency of 40Hz based on the overall system, and the frequency calculation formula is as follows:

[0074]

[0075] Where k is the equivalent stiffness of the overall system and m is the particle mass.

[0076] The expression for the force between the particle and the ultrasonic drill during low-frequency vibration is:

[0077]

[0078] Where, k c δ represents the equivalent contact stiffness between the particle and the drill surface, and δ represents the static deformation of the particle.

[0079] like Figure 4 The diagram shows a schematic of the excitation signal. The horizontal axis represents the excitation time, and the vertical axis represents the excitation voltage. The first curve is a high-frequency sine wave signal, the second curve is a low-frequency sine wave signal, and the third curve is the curve resulting from the superposition of the two signals.

[0080] A beat wave is formed by superimposing two sets of sine waves, such as Figure 5 As shown, this scheme can achieve higher energy for particles at their maximum amplitude, significantly enhancing the ultrasonic-assisted particle motion effect, while maintaining the average power of the ultrasonic drill at its constant value; it can also maintain the ultrasonic-assisted particle motion effect at its minimum amplitude. The two sets of sine waves are:

[0081]

[0082] Where A1 and A2 are the amplitudes of the two sets of sine waves, and ω1 and ω2 are the angular velocities of the two sets of sine waves. and Let be the initial phase of the two sets of sine waves. The expressions for the two sets of sine waves are:

[0083]

[0084] The two sets of sine waves superimposed are:

[0085]

[0086] Among them, A 12 Let be the beat frequency amplitude, which varies over time. The expression for the amplitude is as follows:

[0087]

[0088] Reference Figure 6 To reduce the energy loss of the ultrasonic drill, the low-power drive control method provided in this embodiment can use periodic intermittent sinusoidal waves to excite the ultrasonic transducer. The intermittent period T1 and continuous time T2 of the high-frequency sinusoidal signal and the low-frequency sinusoidal signal are as follows:

[0089]

[0090] Where f1 is the frequency of the low-frequency sine wave signal and f2 is the frequency of the high-frequency sine wave signal.

[0091] The average power of the ultrasonic drill is adjusted by regulating the discontinuity period and discontinuity time of the high-frequency and low-frequency sinusoidal signals. Figure 5 This is a schematic diagram of a periodically discontinuous sine wave.

[0092] The low-power beat wave driving method provided in this embodiment reduces the frictional resistance between the ultrasonic drill and the particles by superimposing high-frequency and low-frequency signals, while increasing the thrust of the particles rising, reducing the torque and critical speed of the spindle rotary motor, thereby reducing the power of the motor and reducing energy consumption during the sampling process.

[0093] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. In particular, for the device embodiments, the above descriptions are merely preferred embodiments of the present invention. Since they are fundamentally similar to the method embodiments, the descriptions are relatively simple, and relevant parts can be referred to the descriptions of the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention, without departing from the principle of the present invention, should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A low-power beat wave driving method for ultrasonic-assisted drilling sampling, characterized in that, Includes the following steps: S1. Input a set of high-frequency sine wave signals and a set of low-frequency sine wave signals, superimpose them to form a new beat frequency wave signal, use the beat frequency signal to excite the ultrasonic transducer, the piezoelectric ceramic sheet of the ultrasonic transducer undergoes mechanical deformation, thereby exciting the longitudinal vibration of the ultrasonic drill; The average power of the ultrasonic drill is adjusted by regulating the discontinuity period and discontinuity time of the high-frequency and low-frequency sinusoidal signals; the discontinuity period T1 and continuous time T2 of the high-frequency and low-frequency sinusoidal signals are given by the following formulas: Where f1 is the frequency of the low-frequency sine wave signal and f2 is the frequency of the high-frequency sine wave signal; The low-frequency sine wave signal is determined based on the overall system structure, and its frequency is calculated using the following formula: Where k is the equivalent stiffness of the overall system, and m is the particle mass; the expression for the force between the particle and the ultrasonic drill during low-frequency vibration is: Where, k c δ represents the equivalent contact stiffness between the particle and the drill surface, and δ represents the static deformation of the particle. The high-frequency sinusoidal signal is determined based on the overall system structure, and the frequency calculation formula is as follows: Where L is the effective length of the drill pipe, E is the dynamic elastic modulus of the material, and ρ is the density of the material; The vibration of an ultrasonic drill consists of two sets of superimposed sine waves forming a beat wave. The two sets of sine waves are: Where A1 and A2 are the amplitudes of the two sets of sine waves, and ω1 and ω2 are the angular velocities of the two sets of sine waves. and Let be the initial phase of the two sets of sine waves; the expressions for the two sets of sine waves are: The two sets of sine waves superimposed are: Among them, A 12 Let be the beat frequency amplitude, which varies over time. The expression for the amplitude is as follows: S2. The drive control system provides DC voltage to the spindle rotary motor to drive the spindle rotary motor. The output end of the motor is connected to the ultrasonic drill through the transmission shaft and the torque is transmitted through the key connection to drive the ultrasonic drill to rotate.

2. The low-power beat wave driving method for ultrasonic-assisted drilling sampling according to claim 1, characterized in that: The ultrasonic drill includes a piezoelectric ultrasonic transducer and a spiral rod, which are connected by threads.

3. The low-power beat wave driving method for ultrasonic-assisted drilling sampling according to claim 2, characterized in that: A passive damping structure is installed at the non-excitation end of the ultrasonic drill pipe as a vibration absorber to avoid the generation of standing waves by traveling wave reflection.

4. The low-power beat wave driving method for ultrasonic-assisted drilling sampling according to claim 1, characterized in that: The spindle rotary motor is a DC electromagnetic motor with the following power: P = T × ω Based on the forces acting on the particle, the equation of motion for the particle is: Among them, f b cos(α+β)=T / R=μ b mω 2 R, f a =μ a mg cosα, T is the torque of the main spindle motor, f b f is the frictional force between the particle and the pore wall. a μ is the frictional force between the particle and the drill surface. a μ is the coefficient of friction between the particle and the drill surface. b ω is the coefficient of friction between the particle and the borehole, α is the angular velocity of the ultrasonic drill, α is the helix angle of the ultrasonic drill, β is the helix angle of the actual trajectory of the particle, R is the radius of the ultrasonic drill rod, m is the mass of the particle, and g is the acceleration due to gravity.

5. The low-power beat wave driving method for ultrasonic-assisted drilling sampling according to claim 4, characterized in that: The equation of motion for the particle must satisfy: At the critical speed, the following condition must be met: Right now: T / R+Fsinα-mg sinα-μ a mg cosα=0 Where T is the torque of the spindle motor, and μ a μ is the coefficient of friction between the particle and the drill surface. b denoted as the coefficient of friction between the particle and the borehole, R as the radius of the ultrasonic drill rod, m as the mass of the particle, g as the acceleration due to gravity, and α as the helix angle of the ultrasonic drill.

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