Lightweight automatic feed drilling device and control method thereof

Abstract

The application discloses a kind of light automatic feed drilling device and control method thereof, device includes execution module, power module and control module being arranged at the one side of execution module, the middle part of the execution module is provided with vibration unit, the axial direction of the vibration unit is sequentially provided with stator, roller, cage and rotor, the contact surface side of the roller is corrugated surface, the other side is plane, the relative angle between the corrugated surface and the cage is phase angle, the power module includes main motor;Method includes by identifying the current following fluctuation characteristics of main motor caused by load fluctuation, predict the change of main motor current with phase angle or with time, i.e. in phase domain or time domain, so as to give the corresponding feed current compensation of main motor. By the method of current feed compensation, even under the condition of small inertia of power module, the smooth operation of motor can also be realized, the light weight of automatic feed drilling equipment is realized, and the labor load when worker holds operation is reduced.

Description

Technical Field

[0001] This invention relates to a drilling device and its control method, and more particularly to a lightweight automatic feed drilling device and its control method, belonging to the field of equipment processing. Background Technology

[0002] Bolting and riveting are the most common component connection methods in aircraft assembly. These mechanical connections require the fabrication of numerous assembly holes, making hole fabrication a crucial task in aircraft assembly. However, the hole-making process is mostly carried out on-site in limited space, making traditional CNC machine tools and industrial robots difficult to implement due to their limited accessibility. Generally, automated feed drilling equipment is used in conjunction with manual worker movement for hole making. To reduce worker workload and improve efficiency, aircraft manufacturers have placed higher demands on the lightweight design of automated feed drilling equipment.

[0003] When drilling metal materials, automatic feed drilling equipment is generally equipped with a vibration unit to ensure smooth chip removal. This causes the cutting thickness to change periodically during drilling, thereby achieving effective chip breaking. However, while improving chip removal and hole quality, this chip breaking mechanism introduces periodically varying impact drilling loads, namely torque and axial force. These impact loads increase the following error during motor operation, causing fluctuations and distortions in drilling parameters such as speed and feed per revolution, ultimately reducing hole quality and process stability.

[0004] Within a certain range, reducing the servo cycle can improve the tracking error to some extent. However, due to the response characteristics of the motor current loop, there is a limit to the reduction of the servo cycle. When the reduction exceeds the lower limit, it will actually reduce the stability of the system. To further improve the motor's tracking error, existing technologies generally increase the rotational inertia of the power module, including the motor and reduction mechanism, to weaken the acceleration effect of impact loads on the motor. However, this measure inevitably increases the weight of the power module, which contradicts the lightweight requirements of automatic feed drilling equipment. Currently, in mainstream automatic feed drilling equipment on the market, the weight of the motor accounts for more than 30% of the total weight of the handheld part, and the weight of the power module accounts for more than 65% of the total weight of the handheld part. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a lightweight automatic feed drilling device and its control method for reducing the following error during motor operation and reducing the weight of the power module.

[0006] Technical Solution: The lightweight automatic feed drilling device of the present invention includes an execution module, a power module and a control module disposed on one side of the execution module. A vibration unit is disposed in the middle of the execution module. The vibration unit has a stator, rollers, a cage and a rotor arranged axially in sequence. One side of the contact surface of the roller is a corrugated surface and the other side is a flat surface. The relative angle between the corrugated surface and the cage is a phase angle.

[0007] Furthermore, the cage is annular, and the rollers are movably disposed between the stator and the rotor, passing through the annular surface of the cage, and the rollers are evenly distributed on the cage circumferentially.

[0008] Furthermore, the corrugated surface can be disposed on the lower surface of the stator or on the upper surface of the rotor. A first probe is fixed around the periphery of the cage, a second probe is fixed around the periphery of the rotor, and a code disk is provided on the outer surface of the stator.

[0009] Furthermore, when the lower surface of the stator is a corrugated surface, the phase angle The first angle between the cage and the stator is obtained by using the first probe and the code disk.

[0010] Furthermore, when the upper surface of the rotor is a corrugated surface, the phase angle The first angle is subtracted from the second angle of the rotor relative to the stator obtained by the second probe and the code disk.

[0011] Furthermore, the vibration unit is equipped with a sensor to acquire the phase angle in real time. And transmit it to the control module; the power module includes a main motor, an auxiliary motor and a transmission gear set.

[0012] This invention employs a lightweight automatic feed drilling control method for the aforementioned lightweight automatic feed drilling device. By identifying the main motor current following fluctuation characteristics caused by load fluctuations, it predicts the main motor current as a function of phase angle. Or, depending on the change with time t, i.e. in the phase domain or time domain, the corresponding feedforward current compensation is given to the main motor.

[0013] The steps for feedforward current compensation of the main motor current in the phase domain are as follows:

[0014] (a) Determine the phase angle of the vibration signal in real time based on the relative angle between the corrugated surface and the cage. And based on the phase angle The drilling process is divided into periods. If the number of sine waves on the corrugated surface is n, then the width of a single drilling period is 2π / n. Periods are distinguished by the k±x, x∈N period number.

[0015] (b) Based on the automatic feed drilling process, the drilling process is divided into the no-load stage, the drilling entry stage, the stabilization drilling stage, the drilling exit stage, and the retraction stage.

[0016] (c) A process database is established through vibration drilling tests. The process database includes the average current i0 of the main motor during the no-load stage of drilling under different tool parameters, workpiece material parameters, drilling parameters, and vibration parameters; and the average increase in main motor current Δi between adjacent cycles during the drilling stage. r Average decrease in the cutting phase angle Average increase in phase angle During the stable drilling phase, the average current i of the main motor s During the drilling phase, the average increase in main motor current Δi between adjacent cycles t Average increase in the in-cut phase angle Average decrease in phase angle In the initial stage of the tool retraction phase, the average current i of the main motor v ;

[0017] (d) During the drilling process, the main motor current i within a single drilling cycle is monitored in real time and analyzed in the phase domain to determine the current drilling state, as well as the average current of the main motor, the in-cut phase angle, and the out-cut phase angle within the current drilling cycle.

[0018] (e) Based on the current drilling status and in conjunction with the current process database, predict the average current of the main motor, the in-cut phase angle and the out-cut phase angle during the subsequent drilling cycles to be compensated.

[0019] (f) Feedforward current compensation is performed using a specified waveform, and based on the principle of equal work, i.e., the current i within a period corresponds to the phase angle Based on the principle that the integral is equal to the area of ​​the actual required current, the feedforward current parameters are calculated.

[0020] Furthermore, the criteria for determining the feedforward current parameters in the phase domain are as follows:

[0021] (f1) when i avg(k) When <= 2*i0, it is judged as the no-load stage, and the feedforward current is...

[0022] (f2) When 2*i0 avg(k) <0.9*i s When it is determined that the drilling stage has begun, the feedforward current is activated. satisfy:

[0023]

[0024] ​

[0025] i qf_avg(k+2) =i avg(k) -i0+2*Δi r ;

[0026]

[0027] (f3) When i avg(k) >=0.9*i s When the drilling is considered to have entered a stable drilling phase, the feedforward current is adjusted. satisfy:

[0028]

[0029]

[0030] i qf_avg(k+2) =i s -i0;

[0031]

[0032] (f4) When i avg(k) <0.9*i s When it is determined that the drilling phase has begun, the feedforward current is activated. satisfy:

[0033]

[0034]

[0035] i qf_avg(k+2) =i avg(k) -i0-2*Δi r , if i qf_avg(k+2) If i < 0, then let i qf_avg(k+2) =0;

[0036] like but Otherwise, let

[0037] i qf_max(k+2) =0;

[0038] (f5) When i avg(k) <2*i v When the tool retraction phase is entered, the feedforward current is adjusted.

[0039] Furthermore, another method for compensating the feedforward current in the time domain is as follows:

[0040] (h) Based on the automatic feed drilling process, the drilling process is divided into the no-load stage, the drilling entry stage, the stable drilling stage, the drilling exit stage, and the tool retraction stage. Then, the main motor current changes with time t in the continuous time domain at different stages.

[0041] (i) Through vibration drilling tests, a process database was established, including the average current i0 of the main motor during the no-load stage of drilling under different tool parameters, workpiece material parameters, drilling parameters, and vibration parameters; and the average increase in main motor current Δi between adjacent cycles during the drilling stage. r The average increase in actual cutting time per cycle Δt r During the stable drilling phase, the average current i of the main motor s During the drilling phase, the average increase in main motor current Δi between adjacent cycles t The average decrease in actual cutting time per cycle Δt t In the initial stage of the retraction phase, the average current i of the main motor v ;

[0042] (j) Based on the drilling speed r and the number of sinusoidal waves n on the corrugated surface, the approximate value of the vibration period T = 2 / (r*n) is calculated.

[0043] (k) During the drilling process, the main motor current i is monitored in real time and analyzed in the time domain to determine the current drilling status, as well as the average current of the main motor, the entry time and the exit time within the current drilling cycle.

[0044] (l) Based on the current drilling status and combined with the current process database, predict the average current of the main motor, the cutting-in time and the cutting-out time in the subsequent drilling cycles to be compensated.

[0045] (m) Use the specified waveform for feedforward current compensation, and calculate the feedforward current parameters according to the principle of equal work, that is, the integral of the main motor current i with respect to time t within the period is equal to the area of ​​the actual required current.

[0046] Furthermore, the criteria for determining the feedforward current parameters in the time domain are as follows:

[0047] (m1) when i avg(k) When <= 2*i0, it is judged as the no-load stage, and the feedforward current i qf (t) = 0;

[0048] (m2) when 2*i0 avg(k) <0.9*i s When the drilling phase begins, the feedforward current i is adjusted. qf (t) satisfies:

[0049] t qf_in(k+2) =t in(k) -Δt​r ;

[0050] t qf_out(k+2) =t out(k) +Δt r ;

[0051] i qf_avg(k+2) =i avg(k) -i0+2*Δi r ;

[0052] i qf_max(k+2) =2*i qf_avg(k+2) *T / (t qf_out(k+2) -t qf_in(k+2) );

[0053] (m3) when i avg(k) >=0.9*i s When the drilling is considered to have entered a stable drilling phase, the feedforward current i... qf (t) satisfies:

[0054] t qf_in(k+2) =t in(k) ;

[0055] t qf_out(k+2) =t out(k) ;

[0056] i qf_avg(k+2) =i s -i0;

[0057] i qf_max(k+2) =2*i qf_avg(k+2) *T / (t qf_out(k+2) -t qf_in(k+2) );

[0058] (m4) when i avg(k) <0.9*i s When it is determined that the drilling phase has begun, the feedforward current i qf (t) satisfies:

[0059] t qf_in(k+2) =t in(k) +Δt r ;

[0060] t qf_out(k+2) =t out(k) -Δt r ;

[0061] i qf_avg(k+2) =i avg(k) -i0-2*Δi r , if i qf_avg(k+2) If i < 0, then let i qf_avg(k+2) =0;

[0062] If t qf_out(k+2) >t qf_in(k+2) , then i qf_max(k+2) =2*i qf_avg(k+2) *T / (t qf_out(k+2) -t qf_in(k+2) Otherwise, let i qf_max(k+2) =0;

[0063] (m5) when i avg(k) <2*i v When the tool retraction phase is entered, the feedforward current i... qf (t) = 0.

[0064] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) It reduces the following error during motor operation. It proposes a current feedforward compensation method for the impact load characteristics that change regularly during automatic feed drilling. Even under the condition of small inertia of the power module, the motor can run smoothly; (2) It reduces the weight of the power module. By lightweighting the automatic feed drilling device, the weight of the power module is avoided, and the labor load of the worker when operating by hand is reduced. Attached Figure Description

[0065] Figure 1 This is a partial exploded view of the lightweight automatic feed drilling device of the present invention;

[0066] Figure 2 This is a circumferential unfolded schematic diagram of an embodiment of the drilling device of the present invention with the corrugated surface of the stator;

[0067] Figure 3 This is a schematic diagram showing the relationship between the axial vibration displacement of the drilling device of the present invention and the angle of the cage relative to the stator;

[0068] Figure 4 This is a circumferentially unfolded schematic diagram of an embodiment of the drilling device of the present invention in which the corrugated surface of the rotor is the rotor.

[0069] Figure 5 This is a graph showing the change of the vibration drilling load signal over time under machining conditions using the control method of the present invention.

[0070] Figure 6 This is a schematic diagram showing the ideal current of the main motor at different stages during the automatic feed drilling process using the control method of the present invention.

[0071] Figure 7 This is a schematic diagram showing the correspondence between the ideal current and phase angle of the main motor at different stages during the automatic feed drilling process using the control method of the present invention.

[0072] Figure 8 This is a schematic diagram of the feedforward current in the (k+2)th cycle of the control method of the present invention;

[0073] Figure 9 This is a schematic diagram of the feedforward compensation system logic of the control method of the present invention;

[0074] Figure 10 This is a schematic diagram showing the correspondence between the ideal current of the main motor and time in the continuous time domain at different stages during the automatic feed drilling process using the control method of the present invention.

[0075] Figure 11 This is a schematic diagram of the main motor current signal under drilling load in the control method of the present invention.

[0076] Figure 12 This is a schematic diagram of the feedforward current in the (k+2)th cycle of the control method of the present invention;

[0077] Figure 13 This is a schematic diagram of the feedforward compensation system logic of the control method of the present invention. Detailed Implementation

[0078] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0079] like Figure 1 As shown, the present invention provides a lightweight automatic feed drilling device, including an execution module 1, a power module 2 and a control module 3 disposed on one side of the execution module 1. A vibration unit 4 is disposed in the middle of the execution module 1. The vibration unit 4 is provided with a stator 5, rollers 6, a cage 7 and a rotor 8 arranged axially in sequence. One side of the contact surface of the rollers 6 is a corrugated surface 9 and the other side is a plane. The relative angle between the corrugated surface 9 and the cage 7 is the phase angle.

[0080] Preferably, the cage 7 is annular, and the rollers 6 are movably disposed between the stator 5 and the rotor 8, passing through the annular surface of the cage 7. The rollers 6 are evenly distributed on the cage 7 in the circumferential direction.

[0081] Preferably, the corrugated surface 9 can be disposed on the lower surface of the stator 5 or on the upper surface of the rotor 8. The first probe 10 is fixed on the periphery of the cage 7, the second probe 11 is fixed on the periphery of the rotor 8, and the outer surface of the stator 5 is provided with a code disk 12.

[0082] Preferably, when the lower surface of the stator 5 is a corrugated surface 9, such as Figure 2 The diagram shows the circumferential unfolded view of the vibration unit 4. When the rotor 8 rotates relative to the stator 5, the rollers 6 and the cage 7 also rotate. Since the rotational speed of the rotor 8 is different from that of the cage 7, the relative positions of the rotor 8 and the rollers 6 change, resulting in periodic axial vibration. The axial vibration displacement depends on the angle of the cage relative to the stator. The first angle of the cage 7 relative to the stator 5, obtained by the first probe 10 and the code disk 12, is the phase angle. When roller 6 contacts the highest point of stator 5, the angle between the cage and the stator is calibrated to 0, which is also the maximum value of the axial vibration displacement; axial vibration displacement z v The relationship between the angle of the cage and the stator is as follows: Figure 3 As shown, n is the number of periods of the surface sinusoidal wave of the corrugated surface 9.

[0083] Preferably, when the upper surface of the rotor 8 is a corrugated surface 9, such as... Figure 4 The diagram shows the circumferential unfolding of the vibration unit 4. The phase angle is obtained by subtracting the first angle from the second angle of the rotor 8 relative to the stator 5 obtained by the second probe 11 and the encoder 12.

[0084] Preferably, the vibration unit 4 is equipped with a sensor to obtain the phase angle in real time. And transmit it to the control module 3; the power module 2 includes a main motor, an auxiliary motor and a transmission gear set.

[0085] Figure 5 The figure shows the variation of the load signal over time during vibration drilling under certain machining conditions. It can be seen from the figure that the load fluctuation during automatic feed drilling is at the same frequency as the tool vibration and strongly correlated with its phase. Therefore, the phase angle during drilling should be adjusted accordingly. The data is transmitted in real time to control module 3, which then adjusts the phase angle accordingly. The numerical values ​​and feedforward compensation algorithm provide the main motor with the required current feedforward compensation signal at the precise time, which can effectively weaken the acceleration effect of load fluctuations on the motor.

[0086] This embodiment selects the case where the lower surface of the stator 5 is a corrugated surface 9 for detailed description. The case where the upper surface of the rotor 8 is a corrugated surface 9 should also be considered within the scope of protection of this patent.

[0087] This invention provides a lightweight automatic feed drilling control method, which predicts the main motor current as a function of phase angle by identifying the main motor current following the fluctuation characteristics caused by load fluctuations. Alternatively, it can vary with time t, i.e. in the phase domain or time domain, thereby providing the main motor with corresponding feedforward current compensation.

[0088] The specific steps for feedforward current compensation of the main motor current in the phase domain are as follows:

[0089] Step a: Determine the phase angle of the vibration signal in real time based on the relative angle between the corrugated surface 9 and the cage 7. And based on the phase angle The drilling process is divided into cycles. Let the number of sine waves on the corrugated surface 9 be n. Then the width of a single drilling cycle is 2π / n. The cycles are distinguished by the k±x, x∈N cycle number.

[0090] Step b: According to the automatic feed drilling process, such as Figure 6 The diagram shown illustrates the ideal current of the main motor. The drilling process is divided into four stages: no-load stage, drilling entry stage, stable drilling stage, drilling exit stage, and tool retraction stage. For ease of understanding, the fluctuation of the main motor current signal is simplified as a triangular waveform. Therefore, in different stages, the main motor current changes with the phase angle in the phase domain. Changes, such as Figure 7 As shown.

[0091] Step c: Establish a process database through vibration drilling tests. The process database includes the average current i0 of the main motor during the no-load stage of drilling under different tool parameters, workpiece material parameters, drilling parameters, and vibration parameters; and the average increase in main motor current Δi between adjacent cycles during the drilling stage. r Average decrease in the cutting phase angle Average increase in phase angle During the stable drilling phase, the average current i of the main motor s During the drilling phase, the average increase in main motor current Δi between adjacent cycles t Average increase in the in-cut phase angle Average decrease in phase angle In the initial stage of the tool retraction phase, the average current i of the main motor v .

[0092] Step d: During the drilling process, monitor the main motor current i in real time within a single drilling cycle, and analyze it in the phase domain to determine the current drilling state, as well as the average current of the main motor, the in-cut phase angle, and the out-cut phase angle within the current drilling cycle.

[0093] like Figure 7 As shown, the main motor current i signal sampled in the k-th cycle is analyzed in the phase domain to obtain the average current i. avg(k) ; when i avg(k) When the current is greater than 2*i0, a significant drilling load can be determined. Based on the current signal, the infeed phase angle within the current cycle can be fitted. and cut-out phase angle

[0094] Step e: Based on the current drilling status and in conjunction with the current process database, predict the average current of the main motor, the in-cut phase angle, and the out-cut phase angle during the subsequent drilling cycles to be compensated.

[0095] Step f: Perform feedforward current compensation using a specified waveform, and based on the principle of equal work, i.e., the current i within the period corresponds to the phase angle... Based on the principle that the integral is equal to the area of ​​the actual required current, the feedforward current parameters are calculated.

[0096] To ensure the effectiveness of feedforward, the phase and magnitude of the feedforward current must be as equal as possible to the actual current required to overcome the load. In practical applications, the feedforward current waveform can be approximated using various forms such as triangular waves and trapezoidal waves for engineering compensation. However, it is essential to ensure that the work done by the feedforward current is close to the energy required to overcome the drilling load, i.e., the principle of equal work. Therefore, the feedforward current in... The projected area of ​​the axis, and the relationship between the main motor current i and the phase angle during the analysis period. The integral is equal to the projected area of ​​the actual required current; this embodiment uses a triangular waveform as an example for description, but embodiments using other waveforms should also be considered within the scope of protection of this patent. Based on the analysis results of the k-th cycle, the feedforward current curve of the k+2-th cycle is calculated. like Figure 8 As shown, the overall feedforward compensation logic is as follows: Figure 9 As shown.

[0097] The criteria for determining the feedforward current parameters in the phase domain are as follows:

[0098] Determine f1: when i avg(k) When <= 2*i0, it is judged as the no-load stage, and the feedforward current is...

[0099] Determine f2: when 2*i0 avg(k) <0.9*i s When it is determined that the drilling stage has begun, the feedforward current is activated. satisfy:

[0100]

[0101]

[0102] i qf_avg(k+2) =i avg(k) -i0+2*Δi r ;

[0103]

[0104] Determine f3: when i avg(k) >=0.9*i s When the drilling is considered to have entered a stable drilling phase, the feedforward current is adjusted. satisfy:

[0105]

[0106]

[0107] i qf_avg(k+2) =i s -i0;

[0108] ​

[0109] Determine f4: when i avg(k) <0.9*i s When it is determined that the drilling phase has begun, the feedforward current is activated. satisfy:

[0110]

[0111]

[0112] i qf_avg(k+2) =i avg(k) -i0-2*Δi r , if i qf_avg(k+2) If i < 0, then let i qf_avg(k+2) =0;

[0113] like but Otherwise, let

[0114] i qf_max(k+2) =0.

[0115] Determine f5: when i avg(k) <2*i v When the tool retraction phase is entered, the feedforward current is adjusted.

[0116] Another embodiment of the present invention performs feedforward current compensation on the main motor current in the phase domain, and the specific steps are as follows:

[0117] Step h: Based on the automatic feed drilling process, the ideal current diagram of the main motor is as follows: Figure 6 As shown, the drilling process is divided into the no-load stage, the drilling entry stage, the stable drilling stage, the drilling exit stage, and the tool retraction stage. For ease of understanding, the fluctuation of the main motor current signal is simplified as a triangular waveform. The corresponding relationship between the main motor current and time t in the continuous time domain for different drilling stages is as follows: Figure 10 As shown.

[0118] Step i: Establish a process database through vibration drilling tests, including tool parameters, workpiece material parameters, drilling parameters, vibration parameters, and the average current i0 of the main motor during the no-load stage of drilling; and the average increase Δi of the main motor current in adjacent cycles during the drilling entry stage. r The average increase in actual cutting time per cycle Δt r During the stable drilling phase, the average current i of the main motor s During the drilling phase, the average increase in main motor current Δi between adjacent cycles t The average decrease in actual cutting time per cycle Δt tIn the initial stage of the retraction phase, the average current i of the main motor v .

[0119] Step j: Based on the drilling speed r and the number of sinusoidal waves n on the corrugated surface 9, calculate the approximate value of the vibration period T = 2 / (r*n).

[0120] During the drilling process, the roller 6 will slide relative to the surface of the stator 5 or rotor 8, resulting in a slight deviation between the actual vibration period T' and T.

[0121] Step k: During the drilling process, monitor the main motor current i in real time and analyze it in the time domain to determine the current drilling status, as well as the average current of the main motor, the entry time, and the exit time within the current drilling cycle.

[0122] like Figure 11 As shown, the average current i over a time width T is analyzed in the time domain during the k-th cycle. avg , when i avg(k) When the current exceeds 2*i0, a significant drilling load can be identified, at which point the main motor current signal exhibits relatively obvious periodic fluctuations. Based on the signal characteristics, the current signal is divided into periods in the time domain, and the current signal within the k-th period is analyzed to obtain the average current i. avg(k) And fit the cut-in time t within the current period. in(k) and cut-out time t out(k) .

[0123] Step 1: Based on the current drilling status and combined with the current process database, predict the average current of the main motor, the entry time, and the exit time during the subsequent drilling cycles to be compensated.

[0124] Step m: Perform feedforward current compensation using a specified waveform, and calculate the feedforward current parameters based on the principle of equal work, i.e., the integral of the main motor current i with respect to time t within the cycle is equal to the area of ​​the actual required current.

[0125] To ensure the effectiveness of the feedforward, the timing and magnitude of the feedforward current must be as close as possible to the actual current required to overcome the load. In practical applications, the feedforward current waveform can be approximated using various forms such as triangular waves and trapezoidal waves for engineering compensation. However, it is necessary to ensure that the work done by the feedforward current is close to the energy required to overcome the drilling load, i.e., the principle of equal work. Therefore, the projected area of ​​the feedforward current on the time axis, the integral of the main motor current i with respect to time t within the analysis period, is equal to the area of ​​the actual required current. This embodiment uses a triangular waveform as an example for description; embodiments using other waveforms should also be considered within the scope of protection of this patent. Based on the analysis results of the kth period, the feedforward current curve i of the (k+2)th period is calculated. qf (t), such as Figure 12 As shown, the overall feedforward compensation logic is as follows: Figure 13 As shown.

[0126] The criteria for determining the feedforward current parameters in the time domain are as follows:

[0127] Determine m1: when i avg(k) When <= 2*i0, it is judged as the no-load stage, and the feedforward current i qf (t) = 0.

[0128] Determine m2: when 2*i0 avg(k) <0.9*i s When the drilling phase begins, the feedforward current i is adjusted. qf (t) satisfies:

[0129] t qf_in(k+2) =t in(k) -Δt r ;

[0130] t qf_out(k+2) =t out(k) +Δt r ;

[0131] i qf_avg(k+2) =i avg(k) -i0+2*Δi r ;

[0132] i qf_max(k+2) =2*i qf_avg(k+2) *T / (t qf_out(k+2) -t qf_in(k+2) ).

[0133] Determine m3: when i avg(k) >=0.9*i s When the drilling is considered to have entered a stable drilling phase, the feedforward current i... qf (t) satisfies:

[0134] t qf_in(k+2) =t in(k) ;

[0135] t qf_out(k+2) =t out(k) ;

[0136] i qf_avg(k+2) =i s -i0;

[0137] i qf_max(k+2) =2*i qf_avg(k+2) *T / (t qf_out(k+2) -t qf_in(k+2) ).

[0138] Determine m4: when i avg(k) <0.9*i s ​When it is determined that the drilling phase has begun, the feedforward current i qf (t) satisfies:

[0139] t qf_in(k+2) =t in(k) +Δt r ;

[0140] t qf_out(k+2) =t out(k) -Δt r ;

[0141] i qf_avg(k+2) =i avg(k) -i0-2*Δi r , if i qf_avg(k+2) If i < 0, then let i qf_avg(k+2) =0;

[0142] If t qf_out(k+2) >t qf_in(k+2) , then i qf_max(k+2) =2*i qf_avg(k+2) *T / (t qf_out(k+2) -t qf_in(k+2) Otherwise, let i qf_max(k+2) =0.

[0143] Determine m5: when i avg(k) <2*i v When the tool retraction phase is entered, the feedforward current i... qf (t) = 0.

[0144] This invention is applied to automatic feed drilling equipment with a hole-making capacity of 12mm. It can significantly improve the speed fluctuation during the drilling process. Compared with existing automatic feed drilling equipment, the hole-making capacity can be increased to 14mm under the same speed fluctuation of less than or equal to 10%. Similarly, in the design stage of automatic feed drilling equipment, based on the beneficial effects of this invention, the power module components are designed or selected with low inertia and lightweight. For automatic feed drilling equipment with a hole-making capacity of 12mm, the overall weight of the automatic feed drilling equipment can be reduced by more than 10% under the same speed fluctuation of less than or equal to 10%.

[0145] In summary, by employing current feedforward compensation to address the regularly changing impact load characteristics during automatic feed drilling, the motor can operate smoothly even with a small inertia in the power module, thereby reducing the following error during motor operation. Furthermore, by lightweighting the automatic feed drilling device, the increased weight of the power module is avoided, reducing the workload for workers performing manual operations.

Claims

1. A lightweight automatic feed drilling control method for a lightweight automatic feed drilling device, the lightweight automatic feed drilling device comprising an execution module (1), a power module (2), and a control module (3), wherein a vibration unit (4) is provided in the middle of the execution module (1), and the vibration unit (4) is provided with a stator (5), rollers (6), a cage (7), and a rotor (8) in sequence along its axial direction, characterized in that, One side of the contact surface of the roller (6) is a corrugated surface (9), and the other side is a flat surface. The relative angle between the corrugated surface (9) and the cage (7) is the phase angle. ; The lightweight automatic feed drilling control method includes the following steps: (a) The phase angle of the vibration signal is determined in real time based on the relative angle between the corrugated surface (9) and the cage (7). And according to the phase angle Divide the drilling process into cycles; (b) Based on the automatic feed drilling process, the drilling process is divided into the no-load stage, the drilling entry stage, the stable drilling stage, the drilling exit stage, and the retraction stage. (c) Establish a process database through vibration drilling tests; (d) During the drilling process, the main motor current in a single drilling cycle is monitored in real time, and the current drilling status, as well as the average current of the main motor, the in-cut phase angle and the out-cut phase angle in the current drilling cycle, are analyzed in the phase domain. (e) Based on the current drilling status and the current process database, predict the average current of the main motor, the in-cut phase angle and the out-cut phase angle during the subsequent drilling cycles to be compensated; (f) Feedforward current compensation is performed using a specified waveform, and the feedforward current parameters are calculated based on the principle of equal work, due to the phase angle Since the load is in the same frequency and strongly correlated, the control module (3) accurately provides the main motor current feedforward compensation signal according to the phase angle value and the feedforward current parameter.

2. The lightweight automatic feed drilling control method according to claim 1, characterized in that, The cage (7) is annular, and the rollers (6) are movably disposed between the stator (5) and the rotor (8) through the annular surface of the cage (7). The rollers (6) are evenly distributed on the cage (7) in the circumferential direction.

3. The lightweight automatic feed drilling control method according to claim 1, characterized in that, The corrugated surface (9) can be disposed on the lower surface of the stator (5) or on the upper surface of the rotor (8). A first probe (10) is fixed on the periphery of the cage (7), a second probe (11) is fixed on the periphery of the rotor (8), and a code disk (12) is provided on the periphery surface of the stator (5).

4. The lightweight automatic feed drilling control method according to claim 3, characterized in that, When the lower surface of the stator (5) is a corrugated surface (9), the phase angle To obtain the first angle between the cage (7) and the stator (5) by means of the first probe (10) and the code disk (12).

5. The lightweight automatic feed drilling control method according to claim 4, characterized in that, When the upper surface of the rotor (8) is a corrugated surface (9), the phase angle The first angle is subtracted from the second angle of the rotor (8) relative to the stator (5) obtained by the second probe (11) and the code disk (12).

6. The lightweight automatic feed drilling control method according to claim 5, characterized in that, The vibration unit (4) is equipped with a sensor, which acquires the phase angle in real time. The power module (2) is a main motor, an auxiliary motor and a transmission gear set.

7. The lightweight automatic feed drilling control method according to claim 1, characterized in that, The criteria for determining the feedforward current parameters in the phase domain in step (f) are as follows: (f1) When the average current of the current in the current drilling state is less than or equal to twice the average no-load current, it is determined that this is the no-load stage and the feedforward current compensation is 0. (f2) When the average current during the current drilling state is greater than twice the average no-load current and less than 0.9 times the average steady current, it is determined that this is the drilling stage, and the feedforward current compensation is calculated. (f3) When the average current of the current in the current drilling state is greater than or equal to 0.9 times the average current of the steady state, it is determined that the steady drilling stage has been entered, and the feedforward current compensation is calculated. (f4) When the average current of the current in the current drilling state is less than 0.9 times the average stable current, it is determined that the drilling exit stage has been entered, and the feedforward current compensation is calculated. (f5) When the average current of the current in the current drilling state is less than twice the average retraction current, it is determined that the retraction stage has been entered and the feedforward current compensation is 0.

8. The lightweight automatic feed drilling control method according to claim 1, characterized in that, Another method for time-domain compensation of the feedforward current includes the following steps: (h) Based on the automatic feed drilling process, the drilling process is divided into the no-load stage, the drilling entry stage, the stable drilling stage, the drilling exit stage, and the tool retraction stage. (i) Establish a process database through vibration drilling tests; (j) Based on drilling speed The number of sine waves on the corrugated surface (9) Calculate the vibration period value ; (k) During the drilling process, monitor the main motor current in real time. In the time domain, the current drilling status, as well as the average current of the main motor, the entry time, and the exit time within the current drilling cycle are determined. (l) Based on the current drilling status and combined with the current process database, predict the average current of the main motor, the cutting-in time and the cutting-out time in the subsequent drilling cycles to be compensated. (m) Use the specified waveform for feedforward current compensation, and calculate the feedforward current parameters according to the principle of equal work.

9. The lightweight automatic feed drilling control method according to claim 8, characterized in that, The criteria for determining the feedforward current parameters in step (m) in the time domain are as follows: (m1) When the average current of the current in the current drilling state is less than or equal to twice the average no-load current, it is determined that this is the no-load stage, and the feedforward current compensation is 0. (m2) When the average current during the current drilling state is greater than twice the average no-load current and less than 0.9 times the average steady current, it is determined that this is the drilling stage, and the feedforward current compensation is calculated. (m3) When the average current of the current in the current drilling state is greater than or equal to 0.9 times the average current of the steady state, it is determined that the steady drilling stage has been entered, and the feedforward current compensation is calculated. (m4) When the average current during the current drilling state is less than 0.9 times the average stable current, it is determined that the drilling exit stage has begun, and the feedforward current compensation is calculated. (m5) When the average current of the current in the current drilling state is less than twice the average retraction current, it is determined that the retraction stage has been entered and the feedforward current compensation is 0.

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