Low-power-consumption beat traveling wave driving method for ultrasonic-assisted drilling and sampling device

Abstract

The invention discloses a low-power-consumption beat traveling wave driving method for an ultrasonic-assisted drilling sampling device, which comprises the following steps: a driving control system gives a group of high-frequency sine wave signals and a group of low-frequency sine wave signals, and the high-frequency sine wave signals and the low-frequency sine wave signals are superposed to form new beat frequency wave signals; an ultrasonic transducer is driven through a beat frequency signal, and an electric ceramic piece of the ultrasonic transducer is subjected to mechanical deformation so as to excite longitudinal vibration of an ultrasonic drill; the maximum amplitude of beat traveling waves generated by superposition of two groups of sine waves is increased under the condition that the average power of the ultrasonic drill is not changed, so that the efficiency of ultrasonic-assisted particle movement is further improved, the critical rotating speed of a main shaft is reduced, the sampling efficiency of soil particles is improved, and the energy consumption of the whole system is reduced; in addition, a passive damping section is arranged at the non-excitation end of the ultrasonic drill rod, traveling waves transmitted from the excitation end are absorbed, and standing waves are prevented from being generated.

Description

Technical Field

[0001] The invention relates to the field of ultrasonic assisted drilling sampling, and in particular to a low-power consumption driving control method for an ultrasonic assisted drilling sampling device. Background Art

[0002] With the continuous development of deep space exploration technology, asteroid exploration has gradually become a research hotspot. Since asteroids contain geological information from the early formation of the solar system, studying asteroids helps us understand the formation and evolution of the solar system. In existing asteroid exploration missions, obtaining asteroid rock samples has become an important goal of deep space exploration.

[0003] Drilling sampling is an important way to obtain rock samples. Existing drilling sampling methods mainly rely on traditional sampling equipment with electromagnetic motors as the power source. Generally, as the drilling sampling depth increases, the required drilling pressure and driving torque of the sampling device also increase, and soil particle accumulation problems will occur. However, the payload and energy carried by the detector are limited, and it is difficult to meet the continuously increasing drilling pressure and power requirements of traditional sampling equipment.

[0004] In order to solve the problems encountered during the drilling sampling process, researchers proposed an ultrasonic-assisted drilling sampling device, which uses ultrasonic vibration to assist the drill rod in transporting soil particles, effectively improving the transportation efficiency of soil particles. However, a single sinusoidal wave excitation does not efficiently exert the energy of ultrasound. Therefore, a drive control method for an ultrasonic-assisted drilling sampling device is proposed. Summary of the invention

[0005] In view of the above problems, the present invention provides a low-power drive control method for ultrasonic-assisted drilling sampling, which is used in an ultrasonic-assisted drilling sampling device and can further improve the transportation efficiency of soil particles and reduce energy consumption during the sampling process.

[0006] To achieve the above object, 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, use the beat frequency signal to excite the ultrasonic transducer, and the piezoelectric ceramic piece of the ultrasonic transducer undergoes mechanical deformation to excite the longitudinal vibration of the ultrasonic drill;

[0008] The average power of ultrasonic drilling can be adjusted by adjusting the intermittent period and intermittent time of the high-frequency sine wave signal and the low-frequency sine wave signal; the intermittent period T of the high-frequency sine wave signal and the low-frequency sine wave signal is 1 , continuous time T 2 The following formula:

[0009]

[0010] Among them, f 1 is the frequency of the low-frequency sine wave signal, f 2 is the frequency of the high-frequency sine wave signal;

[0011] Among them, the low-frequency sine wave signal is determined according to the overall structure of the system, and the frequency calculation formula is:

[0012]

[0013] Where k is the equivalent stiffness of the whole system, and m is the mass of the particle. When vibrating at low frequency, the force between the particle and the ultrasonic drill is expressed as:

[0014]

[0015] Among them, k c is the equivalent contact stiffness between the particle and the drill surface, δ is the static deformation of the particle;

[0016] The high-frequency sine wave signal is determined according to the overall structure of the system, and the frequency calculation formula is:

[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 ultrasonic drilling is a superposition of two sets of sine waves to form a beat wave. The two sets of sine waves are:

[0020]

[0021] Among them, A 1 and A 2 is the amplitude of the two sets of sine waves, ω 1 and ω 2 are the angular velocities of the two sets of sine waves, and is the initial phase of the two sets of sine waves; the expressions of the two sets of sine waves are:

[0022]

[0023] The superposition of two sets of sine waves is:

[0024]

[0025] Among them, A 12 is the beat frequency amplitude, and it changes with time. The amplitude expression is as follows:

[0026]

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

[0028] Optionally, the ultrasonic drill includes a piezoelectric ultrasonic transducer and a spiral rod, and the transducer and the spiral rod are connected via threads.

[0029] Optionally, in order to improve the ultrasonic assisted drilling sampling effect, a passive damping structure is set at the other end of the ultrasonic drill rod as a vibration absorber to avoid the reflection of the traveling wave to form standing wave. In this embodiment, polyoxymethylene is used as a passive damping material. The transmission of the traveling wave makes the effect of ultrasonic assisted drilling sampling the same on the rod, and the effect of ultrasonic assisted drilling sampling will not be affected by the existence of standing wave nodes.

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

[0031] P=T×ω

[0032] According to the force on the particle, the equation of motion of 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 spindle motor, f b is the friction between the particle and the pore wall, f a is the friction between the particle and the drill surface, μ a is the friction coefficient between the particle and the drill surface, μ b is the friction coefficient between the particle and the drill hole, ω is the angular velocity of the ultrasonic drill, α is the helix angle of the ultrasonic drill, β is the rise angle of the actual motion 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 of gravity.

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

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

[0037] The ultrasonic drill is stimulated by a sine wave signal of ultrasonic frequency to generate longitudinal vibration. The waves on the ultrasonic drill generate standing waves due to reflection and superposition. According to the Chladni effect of ultrasound on particles, particles will gather near nodes under the action of ultrasound, where the energy transmitted to particles by ultrasound is the lowest. The auxiliary effect of ultrasound on drilling sampling will show periodic fluctuations, and the particle energy is zero at the node.

[0038] Furthermore, in order to improve the effect of ultrasonic-assisted drilling, a group of high-frequency sine wave signals and a group of low-frequency sine wave signals are applied to the ultrasonic drill through the driving control system, and the high-frequency sine wave signals and the low-frequency sine wave signals are used to drive the piezoelectric ceramic piece to undergo periodic mechanical deformation, thereby stimulating the longitudinal vibration of the ultrasonic drill;

[0039] Optionally, the frequency calculation of the ultrasonic drill involves multiple factors, including the dynamic elastic modulus, density and geometric dimensions of the sample of the material. The frequency is near the resonant frequency point of the ultrasonic drill and can excite the third-order longitudinal vibration of the ultrasonic drill;

[0040] The ultrasonic drilling frequency 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 / m 3 ).

[0043] Ultrasonic frequency vibration can produce a cavitation layer between the particles and the drill surface, reducing the friction coefficient μ between the particles and the drill surface. a , reducing the friction resistance received by particles during their ascent.

[0044] Beneficial effects:

[0045] The invention discloses a low-power consumption beat wave driving method for an ultrasonic assisted drilling sampling device, comprising: a driving control system provides a group of high-frequency sine wave signals and a group of low-frequency sine wave signals, which are superimposed to form a new beat wave signal; an ultrasonic transducer is driven by the beat signal, and an electric ceramic sheet of the ultrasonic transducer undergoes mechanical deformation to stimulate the longitudinal vibration of an ultrasonic drill; the beat wave generated by the superposition of the two groups of sine waves increases the maximum amplitude under the condition that the average power of the ultrasonic drill remains unchanged, further improves the efficiency of ultrasonic assisted particle movement, reduces the critical speed of the main shaft, increases the sampling efficiency of soil particles, and reduces the overall energy consumption of the system; in addition, a passive damping section is arranged at the non-excitation end of the ultrasonic drill rod to absorb the traveling wave transmitted from the excitation end to avoid the generation of standing waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0048] Figure 2 A schematic diagram of the ultrasonic drill provided by the present invention;

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

[0050] Figure 4 A schematic diagram of superposition of two groups of signals provided by the present invention;

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

[0052] Figure 6 Schematic diagram of the periodic discontinuous sine wave provided by the present invention. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0055] Firstly, a group of high-frequency sine wave signals and a group of low-frequency sine wave signals are input, and superimposed to form a new beat frequency wave signal, and the beat frequency signal is used to excite the ultrasonic transducer, so that the piezoelectric ceramic piece of the ultrasonic transducer undergoes mechanical deformation, thereby stimulating the longitudinal vibration of the ultrasonic drill;

[0056] Secondly, the drive control system provides a DC voltage to the spindle rotation motor to drive the spindle rotation motor. The output end of the motor is connected to the ultrasonic drill through a transmission shaft, and the torque is transmitted through a 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, and the transducer and the spiral rod are connected by threads;

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

[0059] P=T×ω

[0060] like Figure 3 As shown in the figure, according to the force applied to the particle, the equation of motion of 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 spindle motor, f b is the friction between the particle and the pore wall, f a is the friction between the particle and the drill surface, μ a is the friction coefficient between the particle and the drill surface, μ b is the friction coefficient between the particle and the drill hole, ω is the angular velocity of the ultrasonic drill, α is the helix angle of the ultrasonic drill, β is the rise angle of the actual motion 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 of gravity.

[0063] In order to ensure that soil particles can be discharged normally, the motion equation of 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 cos α = 0

[0065] In this implementation, a 20kHz sine wave signal is used to excite the ultrasonic drill to generate longitudinal vibration. The waves on the ultrasonic drill generate standing waves due to reflection and superposition. According to the Chladni effect of ultrasound on particles, the particles will gather near the nodes under the action of ultrasound, where the energy transmitted to the particles by ultrasound is the lowest. The auxiliary effect of ultrasound on drilling sampling will show periodic fluctuations, and the particle energy is zero at the nodes.

[0066] Furthermore, in order to improve the ultrasonic assisted drilling sampling effect, a passive damping structure is set at the other end of the ultrasonic drill rod as a vibration absorber to avoid the formation of standing waves due to reflection. In this embodiment, polyoxymethylene is used as a passive damping material. Figure 2 As shown, the transmission of traveling waves makes the effect of ultrasonic-assisted drilling and sampling the same on the rod, and the effect of ultrasonic-assisted drilling and sampling will not be affected by the existence of standing wave nodes.

[0067] Furthermore, in order to improve the effect of ultrasonic assisted drilling, the driving control system applies a group of high-frequency sine wave signals and a group of low-frequency sine wave signals as excitation signals to the ultrasonic drill, and the high-frequency sine wave signals and the low-frequency sine wave signals are used to drive the piezoelectric ceramic piece to undergo periodic mechanical deformation, thereby stimulating the longitudinal vibration of the ultrasonic drill;

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

[0069] The ultrasonic drilling frequency 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 / m 3 ).

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

[0073] In this embodiment, the low-frequency signal determines the frequency of the excitation voltage to be 40 Hz according to the overall system, and the frequency calculation formula is:

[0074]

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

[0076] When vibrating at low frequency, the force between the particle and the ultrasonic drill is expressed as:

[0077]

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

[0079] like Figure 4 As shown, a schematic diagram of the excitation signal is given. In the figure, the horizontal axis represents the excitation time, 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 a curve after the two signals are superimposed.

[0080] The beat wave is formed by superposition of two sets of sine waves, such as Figure 5As shown in the figure, this scheme can achieve the condition that the average power of ultrasonic drilling remains unchanged, so that the particles can obtain higher energy at the maximum amplitude, greatly improving the effect of ultrasound-assisted particle movement; the effect of ultrasound-assisted particle movement can also be maintained at the minimum amplitude. The two sets of sine waves are:

[0081]

[0082] Among them, A 1 and A 2 is the amplitude of the two sets of sine waves, ω 1 and ω 2 are the angular velocities of the two sets of sine waves, and is the initial phase of the two sets of sine waves. The expressions of the two sets of sine waves are:

[0083]

[0084] The superposition of two sets of sine waves is:

[0085]

[0086] Among them, A 12 is the beat frequency amplitude, and it changes with time. The amplitude expression is as follows:

[0087]

[0088] Reference Figure 6 In order to reduce the energy loss of ultrasonic drilling, the low-power drive control method provided in this embodiment can use periodic intermittent sine waves to excite the ultrasonic transducer, and the intermittent period T of the high-frequency sine wave signal and the low-frequency sine wave signal is 1 , continuous time T 2 The following formula:

[0089]

[0090] Among them, f 1 is the frequency of the low-frequency sine wave signal, f 2 is the frequency of the high-frequency sine wave signal.

[0091] The average power of ultrasonic drilling can be adjusted by adjusting the intermittent period and intermittent time of high-frequency sine wave signal and low-frequency sine wave signal. Figure 5 Schematic diagram of a periodically discontinuous sine wave.

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

[0093] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, the above is only a preferred embodiment of the present invention. Since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field is within the technical scope disclosed by the present invention. For ordinary technicians in the technical field, changes or replacements that can be easily thought of should be covered within the protection scope of the present invention without departing from the principle of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A low-power beat-wave driving method for ultrasonic-assisted drilling sampling, characterized in that: The following steps are involved: 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, so that the piezoelectric ceramic piece of the ultrasonic transducer undergoes mechanical deformation, thereby exciting the longitudinal vibration of the ultrasonic drill; The average power of ultrasonic drilling can be adjusted by adjusting the intermittent period and intermittent time of the high-frequency sine wave signal and the low-frequency sine wave signal; the intermittent period T1 and the continuous time T2 of the high-frequency sine wave signal and the low-frequency sine wave signal are as follows: Among them, f1 is the frequency of the low-frequency sine wave signal, and f2 is the frequency of the high-frequency sine wave signal; Among them, the low-frequency sine wave signal is determined according to the overall structure of the system, and the frequency calculation formula is: Where k is the equivalent stiffness of the whole system, and m is the mass of the particle. When vibrating at low frequency, the force between the particle and the ultrasonic drill is expressed as: Among them, k c is the equivalent contact stiffness between the particle and the drill surface, δ is the static deformation of the particle; The high-frequency sine wave signal is determined according to the overall structure of the system, and the frequency calculation formula is: 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 ultrasonic drilling is a superposition of two sets of sine waves to form a beat wave. The two sets of sine waves are: Among them, A1 and A2 are the amplitudes of the two sets of sine waves, ω1 and ω2 are the angular velocities of the two sets of sine waves, and is the initial phase of the two sets of sine waves; the expressions of the two sets of sine waves are: The superposition of two sets of sine waves is: Among them, A 12 is the beat frequency amplitude, and it changes with time. The amplitude expression is as follows: S2. The drive control system provides a DC voltage to the spindle rotation motor to drive the spindle rotation motor. The output end of the motor is connected to the ultrasonic drill through a transmission shaft, and the torque is transmitted through a 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 comprises a piezoelectric ultrasonic transducer and a spiral rod, and the transducer and the spiral rod are connected by threads.

3. The low-power driving method for ultrasonic-assisted drilling sampling according to claim 2, characterized in that: A passive damping structure is set at the non-excitation end of the ultrasonic drill pipe as a vibration absorber to avoid standing waves caused 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 rotating motor is a DC electromagnetic motor, and the motor power is: P=T×ω According to the force on the particle, the equation of motion of 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 spindle motor, f b is the friction between the particle and the pore wall, f a is the friction between the particle and the drill surface, μ a is the friction coefficient between the particle and the drill surface, μ b is the friction coefficient between the particle and the drill hole, ω is the angular velocity of the ultrasonic drill, α is the helix angle of the ultrasonic drill, β is the rise angle of the actual motion 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 of 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 of the particle must satisfy: At the critical speed, the following conditions are met: Right now: T / R+Fsinα-mg sinα-μ a mg cosα=0 Where T is the torque of the spindle motor, μ a is the friction coefficient between the particle and the drill surface, μ b is the friction coefficient between the particle and the borehole, R is the radius of the ultrasonic drill rod, m is the mass of the particle, g is the gravitational acceleration, and α is the ultrasonic drill helix angle.

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